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Philosophical Classics 
 
 Religion of Science Library No. 51 
 
 Price 40 cents (2s.) 
 
 DESCARTES' MEDITATIONS 
 AND SELECTIONS FROM THE 
 PRINCIPLES OF PHILOSOPHY 
 
 By 
 
 RENE DESCARTES 
 
 CHICAGO 
 
 THE OPEN COURT PUBLISHING COMPANY 
 
 1912 
 
RENE DESCARTES 
 
 (1596-1650) 
 
THE MEDITATIONS 
 
 SELECTIONS FROM THE PRINCIPLES 
 
 RENE DESCARTES 
 
 " (1596-1650) 
 
 TRANSLATED BY 
 
 JOHN VEITCH, LL. D. 
 
 LATE PROFESSOR OF LOGIC AND RHETORIC IN THE UNIVERSITY OF GLASGOW 
 
 WITH A PREFACE, 
 
 COPIES OF ORIGINAL TITLE PAGES, 
 
 A BIBLIOGRAPHY, AND AN ESSAY ON DESCARTES' PHILOSOPHY 
 
 BY L. LÉVY-BRUHL, MAÎTRE DE CONFÉRENCES 
 
 IN THE SORBONNE 
 
 CHICAGO 
 
 THE OPEN COURT PUBLISHING COMPANY 
 1913 
 
3\S5Z 
 

 PUBLISHERS' PREFACE. 
 
 An authorized reprint of Veitch's translation of Descartes' 
 Discourse on Method has already been published as No. 38 
 of the Religion of Science Library. The present volume is 
 a reprint of the remainder of Veitch's translations of 
 Descartes' representative speculative treatises. The Medi- 
 tations on the First Philosophy are translated entire, and 
 the preface and the first part of the Principles of Phi- 
 losophy, together with selections from the second, third and 
 fourth parts of that work, corresponding to the extracts 
 in the French edition of Gamier, are also given, as well 
 as an appendix containing part of Descartes' reply to the 
 Second Objections {vis., his formal demonstrations of the 
 existence of Deity), and Veitch's notes. The translations 
 are based on the original Latin editions of the Meditations 
 and Principles, published respectively in 1641 and 1644. 
 Both works having been translated into French during 
 Descartes' lifetime, and personally revised and corrected by 
 him, the French text is evidently deserving of the same 
 consideration as the Latin originals, and consequently, the 
 additions and variations of the French version have also 
 been given — the additions being put in square brackets in 
 the text and the variations in the footnotes. 
 
 Dr. C. Guttler, of the University of Munich, has just 
 published (Munich: C. H. Beck. 1901) a new critical and 
 annotated edition of both the Latin and French texts of 
 the Meditations, and students desirous of consulting the 
 sources may be referred to this easily accessible book. Dr. 
 Guttler made use of the copy of the original Latin edition 
 (1641), preserved in the Bibliothèque Nationale at Paris, 
 and of the copy of the original French translation by the 
 Duc de Luynes (1647) found in the University Library 
 at Gôttingen. Literal copies of the title-pages of these orig- 
 inal editions, as given in Dr. Guttler's work, are also repro- 
 duced in the present volume. The most recent French edi- 
 tion of the Meditations is that of Emile Thouverez (Paris: 
 Belin Frères. 1898). 
 
 With a view to rendering the volume as complete and 
 serviceable as possible, the publishers have added by way 
 
iv PUBLISHERS' PREFACE. 
 
 of a general introduction, Professor L. Lévy-Bruhl's essay 
 on- the philosophy of Descartes, which appeared in his 
 History of Modem Philosophy in France (Chicago: The 
 Open Court Publishing Co. 1899). A brief bibliography 
 of Cartesian literature has also been appended. 
 
 It merely remains for us to add a few remarks as to the 
 technical history of the Meditations, and to refer to the prev- 
 alent misconception that Descartes regarded his famous dic- 
 tum, Cogito, ergo sum, as having the force of a syllogism. 
 
 The first draft of the Meditations was written in 1629 
 while Descartes was sojourning at a chateau of a noble 
 family named Sjàrdama, in Franeker, a small university town 
 in Friesland. In a letter to Gibieuf, dated July 18, 1629, 
 Descartes speaks of a small metaphysical tract on which 
 he was engaged, and on April 15, 1630, he writes to Mer- 
 senne from Amsterdam that he had devoted the first nine 
 months of his stay in Holland to meditation on the prob- 
 lem as to how the proofs of the truths of metaphysics might 
 be rendered more evident than the demonstrations of geom- 
 etry. The treatise did not see the light however, until 1641. 
 In the meantime, the great work on The World was written 
 (1633) and suppressed, and the Discourse on Method and 
 the treatises on Dioptrics, Meteors, and Geometry (1637) 
 appeared. It was to offset the criticisms which were aimed 
 at these latter works by Fermât, Petit, De Roberval, Voët- 
 ius, Bourdin and others, that in 1639 Descartes took up 
 the draft of the old tract prepared ten years before, to 
 remodel it into an independent and systematic treatise on 
 metaphysics. To forestall all possible animadversions, and 
 to render his exposition explicit on all points, he submitted 
 his manuscript before printing, to a number of learned 
 men for examination and critical analysis. With the so- 
 called Objections, which these critics supplied, and Descartes' 
 answers, the book finally appeared on August 28, 1641. 
 The authors of the Objections were : Caterus, a theologian 
 of Louvain (First Objections) ; Mersenne, Desargues, and 
 anonymous critics (Second and Sixth Objections) ; Hobbes, 
 Arnauld and Gassendi (Third, Fourth and Fifth Objec- 
 tions). In later editions, other Objections were incorpor- 
 ated. The title Meditationes was chosen in contradistinc- 
 tion to the Quaestiones and Disputationes of scholastic liter- 
 ature. 
 
PUBLISHERS' PREFACE. v 
 
 The frequent misconception that Descartes regarded his 
 famous cogito, ergo sum, as having the force of a syl- 
 logism also deserves brief mention. Descartes himself, al- 
 though not always careful as to his mode of expression on 
 this point, has explicitly anticipated the objection so often 
 made to his reasoning. In Meditation II. (see pages 30-33) 
 he omits the "therefore." In his reply to Gassendi's objec- 
 tion that cogito ergo sum implies qui cogitât est, a pre- 
 judgment, Descartes says: 
 
 "The term pre-judgnient is here abused. Prejudgment 
 there is none, when the cogito ergo sum is duly considered, 
 because it then appears so evident to the mind that it can- 
 not keep itself from believing it, the moment even it begins 
 to think of it. But the principal mistake here is this, that 
 the objector supposes that the cognition of particular prop- 
 ositions is always deduced from universals, according to 
 the order of the syllogisms of logic. He thus shows that 
 he is ignorant of the way in which truth is to be sought. 
 For it is settled among philosophers, that in order to find 
 it a beginning must always be made from particular notions, 
 that afterwards the universal may be reached ; although 
 also reciprocally, universals being found, other particulars 
 may thence be deduced." Again he says: "When we ap- 
 prehend that we are thinking things, this is a first notion 
 which is not drawn from any syllogism ; and when some one 
 says, / think, hence I am, or / exist, he does not conclude 
 his existence from his thought as by force of some syl- 
 logism, but as a thing known of itself; he sees from this, 
 that if he deduced it from a syllogism, he must before- 
 hand have known this major, All that which thinks is or 
 exists. Whereas, on the contrary, this is rather taught 
 him, from the fact that he experiences in himself that it 
 cannot be that he thinks if he does not exist. For it is 
 the property of our mind to form general propositions from 
 the knowledge of particulars." 
 
 In other places, also, Descartes has made the same dis- 
 tinct assertion.* Finally, Mr. C. S. Peirce, in The Open 
 Court of June 15, 1893, cites a passage in a letter to Cler- 
 selier : 
 
 "Je pense, donc je suis, ne suppose pas la majeure, Tout 
 ce qui pense existe." T. J. McCORMACK. 
 
 La Salle, 111., September, 1901. 
 
 (♦See M. Cousin's edition, T. I., 247, 403; T. II., 74, 333.) 
 
ESSAY ON DESCARTES. 
 
 BY PROF. L. LÉVY-BRUHL. 
 
 With Descartes a new period of modern philosophy begins. 
 It is not, indeed, a beginning in a literal sense: there is no 
 such thing in the history of ideas, nor elsewhere. Descartes, 
 who came after the great scientific and philosophical illumi- 
 nation of the sixteenth century, had profited largely by it. 
 He owed much to the Italian Renaissance, and not less to 
 the Renaissance in France and in England. He was ac- 
 quainted with the discoveries of contemporary men of science, 
 such as Galileo, Torricelli, and Harvey. Even scholastic 
 philosophy, which he was to combat, left a lasting impression 
 upon his mind. 
 
 However, after we have considered all the influences, both 
 of the past and of the present, which were exercised upon 
 him, the originality of Descartes shines out all the more con- 
 spicuously, and we see the more clearly that he initiated a new 
 philosophic method. Hegel called him a hero, and this hyper- 
 bole may in a certain sense be justified. Descartes had, in- 
 deed, no vocation for martyrdom. But nature had endowed 
 him with that higher sort of courage which is love of truth 
 and devotion to science; and if the name of hero is due the 
 men whose exertions have laid open new paths for human 
 thought, Descartes is undoubtedly entitled to the name. 
 
 The attitude of Descartes toward the philosophers who pre- 
 ceded him is remarkable, — he deliberately ignores them. Al- 
 though well acquainted with their works, he builds his own 
 system as if he knew nothing of them. He wishes to depend 
 solely on his own method and reason. Not that he personally 
 holds in contempt either the ancient or the modern philoso- 
 phers. He is not so presumptuous as to believe that his mind 
 is superior to theirs. He even acknowledges that many 
 truths had been discovered before he created his method, but 
 these truths he does not wish to accept on tradition. He is 
 determined to discover them for himself. By means of his 
 vii 
 
viii ESSAY ON DESCARTES. 
 
 method he proposes to obtain these truths, no longer mixed 
 pell-mell with the mass of doubtful or erroneous opinions, 
 but set in their right places, and accompanied with their 
 proofs. Thus only do they become valuable and useful. For 
 a truth, when isolated, sporadic, and floating and unconnected 
 with the truths that have gone before it, and consequently 
 powerless to develop those that are to come after it, is of 
 slight interest in itself. To acquire such a truth is not worth 
 the trouble we must take in order to understand ancient 
 books, and the time we lose in learning the ancient languages. 
 All this time were better employed in training our reason to 
 grasp the necessary concatenation of truths as deducible one 
 from another. 
 
 This is already a first motive, and a quite sufficient one, 
 for Descartes to dispense with erudition and to take no ac- 
 count of traditional doctrine. But he has another and more 
 weighty one. He seeks not what is probable, but what is 
 true.V'Now the first requisite in finding what is true he takes 
 to be the casting aside of the philosophy taught in his time, 
 which contented itself with probability and gave no satisfac- 
 tory demonstrations. Therefore, though he occasionally re- 
 tains the vocabulary of scholasticism (for instance in the 
 greater part of his Meditations), though he even borrows 
 some of his matter from it (for instance, in the ontological 
 argument, in the theory of continuous creation), nevertheless 
 Descartes broke distinctly and completely with the method 
 and spirit of the philosophy which had been handed down 
 from antiquity through the vicissitudes of the Middle Ages 
 and the struggles of the Renaissance. Even what he seems 
 to borrow from it, he really transforms. Cartesianism not 
 only has a positive meaning, which we shall presently study, 
 but it has to begin with a critical function, and proposes first 
 of all to do away with a philosophical system which, appeal- 
 ing to substantial forms and occult causes, claimed to ex- 
 plain everything and could demonstrate nothing. 
 
 There is accordingly something more in his attitude to his 
 predecessors than a mere protest against the authoritative 
 method, — a protest which had already been raised by eloquent 
 voices in the sixteenth century and even earlier. We have in 
 
ESSAY ON DESCARTES. ix 
 
 it, in fact, a set determination to consider the generally ac- 
 cepted philosophy as null and void, and to replace it with 
 another which shall owe nothing to the former. A bold un- 
 dertaking, not merely of a reformative but of a revolutionary 
 nature. In England, Bacon, while combating the Scholastic 
 Philosophy in the matter of experimental method, neverthe- 
 less derived from it his conception of physical reality. 
 Hobbes, however much he may have freed himself from tra- 
 ditional metaphysics, is nevertheless the heir of the later great 
 English scholastics. In Germany likewise, the genius of Leib- 
 niz is one of conservatism as well as of innovation. He 
 openly disapproves of Descartes's excessive severity toward 
 scholasticism, of which, for his part, he preserves a great 
 deal, in his doctrine as well as in his terminology. Therefore 
 we see his successor Wolf restoring, so to speak, a new 
 scholastic system based on the philosophy of Leibniz. It 
 was this philosophy that Kant imbibed; and later on, after 
 Kant's Kritik, a kind of new scholasticism appeared (in the 
 school of Hegel for instance), indisputably related to that of 
 the Middle Ages. Thus, in Germany, the thread of philosoph- 
 ical tradition was never entirely broken. 
 
 In France, owing to Descartes, the case was altogether dif- 
 ferent. The Cartesian philosophy aimed at nothing less than 
 the utter destruction of its rival. It prevailed; and, as early 
 as the latter part of the seventeenth century, the victory was 
 complete. This was both favorable and unfavorable to the 
 progress of French philosophy. Of course, it was no small 
 advantage for the latter to free itself from the prestige of 
 antiquity, from the tyranny of scholasticism, to regain its 
 full independence, and to draw its inspiration freely from 
 the spirit of the mathematical and physical sciences, the in- 
 creasing power of which was a genuinely new element in the 
 life of mankind. To this the success of Cartesianism, and 
 the fact that its method persisted, even after the doctrine was 
 discarded, bear sufficient testimony. But on the other hand, 
 certain displeasing characteristics of French philosophy in 
 the eighteenth century may, at least in some measure, have 
 originated in this breaking with tradition. A taste for abstract 
 and too simple solutions, a conviction that it is sufficient to 
 
x ESSAY ON DESCARTES. 
 
 argue soundly upon evident principles in order to discover 
 the truth, even in the most complex problems of social life — 
 in short, a lack of historical spirit, with which the French 
 philosophy of that period has been reproached — all these 
 faults are owing in some measure to the spirit of Cartesianism. 
 Certain it is that Descartes and his followers, in their contest 
 with tradition, failed to appreciate its value and necessary 
 function. 
 
 Nothing is so significant in this respect as the way in which 
 these writers speak of history. As it is not a science, it 
 cannot possibly be the basis of a school. It may entertain 
 us, but it cannot really teach us. It is even liable to beget 
 false ideas, and to be an encouragement to extravagant un- 
 dertakings. And, logically speaking, whatever rests on his- 
 torical claims only is insufficiently justified. This last maxim 
 may, in practice, have most serious consequences. Descartes 
 foresaw the attempt that would be made to extend its appli- 
 cation to political and social problems. He therefore openly 
 disclaims beforehand this application, which he personally 
 refuses to make. Yet if he wishes us to abstain from criti- 
 cising existing institutions, it is in his case, as in Montaigne's, 
 for reasons of utility alone. One can easily imagine circum- 
 stances in which considerations of utility would favor the 
 other side. It is, then, a mere question of expediency. 
 
 This tendency to claim that reason alone ought to be the 
 basis of opinion, because reason alone can demonstrate it to 
 be true, and the consequent tendency to make free use of 
 rational criticism, appear in the history which Descartes gives 
 us of his mind. Of all that he learned at school, nothing 
 satisfied him except mathematics. Hardly had he freed him- 
 self from the sway of his masters (the best, he says, there 
 were then in Europe), when he deliberately set about forget- 
 ting their teaching. He speaks only with irony of the various 
 sciences, or so-called sciences : medicine, law, philosophy, as 
 they were taught in his day. He coolly turns his back on 
 belles lettres, and holds history in contempt. Geometry alone 
 found favor in his eyes ; still he wondered greatly at its being 
 used only as an object of amusement for the curious, and 
 that "on so firm a basis nothing more lofty had been estab- 
 
ESSAY ON DESCARTES. xi 
 
 lished." The ground was now cleared; Descartes could begin 
 to build. 
 
 According to some, Descartes is first of all a man of 
 science, and secondly a philosopher. According to others, 
 the philosopher in him predominates over the man of science. 
 In point of fact, philosophy and science were not separated 
 in Descartes's view. He seeks to establish the system of 
 truths accessible to man — a system which he conceived as 
 unique, and which may be figured as an endless chain. And 
 he seeks it in order to find the means of living as uprightly 
 and happily as possible. Thus the end which Descartes has 
 in view is a righteous and happy life : wherein he agrees with 
 the philosophers of his time, and, we may also say, of all 
 times. 
 
 In order to attain to this righteous and happy life, leaving 
 out of account the teachings of religion, Descartes sees no 
 sure way but the possession of truth or science. Now science, 
 in its turn, rests on metaphysics, or primary philosophy, 
 whence it derives its principles. Therefore Descartes pro- 
 poses to be a metaphysician; but this he will be for the sake 
 of science itself. Metaphysics is to him a road, but indeed a 
 road of paramount importance, since all the rest depends 
 upon the principles discovered therein. Besides, mathematics, 
 physics, and other theoretical sciences are also roads, the ter- 
 minal point lying in the applied sciences, to which they lead. 
 "The whole of philosophy," says Descartes, in the Preface to 
 the Principes de la Philosophie, "is like a tree, the roots of 
 which are metaphysics; the trunk is the science of physics; 
 and the branches shooting from that trunk are all the other 
 sciences, which may be reduced to three main ones, viz., medi- 
 cine, mechanics, and ethics, by which last I mean the highest 
 and most perfect ethics, which, since it presupposes a com- 
 plete knowledge of the other sciences, is the supreme degree 
 of wisdom." 
 
 Thus if Descartes is careful to make a distinction between 
 the sphere of action and that of knowledge, and if, before un- 
 dertaking the long and difficult task of seeking after truth, he 
 provides himself with a "provisional" ethics, which he un- 
 questioningly accepts from authority and custom, he never- 
 
xii ESSAY ON DESCARTES. 
 
 theless proclaims the principles of action to be dependent 
 upon knowledge. It is the business of reason not only to 
 enlighten, but also to guide us. Descartes, believing in the 
 future progress of mankind, considers it to be dependent on 
 the development of the sciences. We even observe, in several 
 passages, that the progress of ethics appears to him subordi- 
 nate to that of mechanics and of medicine. But these in 
 their turn depend for their advancement upon the establish- 
 ment of a sound and rigorously demonstrated physical science. 
 Thus, although science is not its own end, the fundamental 
 problem of philosophy according to Descartes is finally re- 
 duced to the problem of the establishment of science. 
 
 Now there is no breach of continuity between metaphysics 
 and physics ; on the contrary, there is a natural and neces- 
 sary transition from the one to the other. Descartes at- 
 tempted to build up a system by means of which one could 
 proceed uninterruptedly from the first principles of cognition 
 and of being, in a word, from God, down to the most specific 
 scientific proposition of physiology or of ethics, without one 
 link missing in the chain. A bold conception, which domi- 
 nates the whole system and is inseparable from the famous 
 method of Descartes. 
 
 Up to this point mathematics alone appeared to Descartes 
 worthy of being called a science. It differs from everything 
 else he had learned in the perfect lucidity of its principles, 
 in the rigorous demonstration of its propositions, and in the 
 inevitable sequence of its truths. But to what does it owe 
 these characteristics, if not to the method from which mathe- 
 maticians make it a rule never to depart? Therefore, in 
 order to establish the science or philosophy sought by Des- 
 cartes, it was sufficient to find a method that should be to 
 philosophy what the method of mathematical deduction is to 
 arithmetic, algebra and geometry. 
 
 To apply to that universal science conceived by Descartes 
 the method so effectively employed in the above-mentioned 
 sciences would evidently be the simplest solution of the prob- 
 lem proposed. But this solution is impracticable. The mathe- 
 matical method, as we see it practiced in "the analysis of the 
 ancients and the algebra of the moderns" is a special method, 
 
ESSAY ON DESCARTES. xiii 
 
 limited to the study of figures in geometry, and confined in 
 algebra to symbols and rules which hamper the mind. How 
 could one pass from these processes, which are especially 
 adapted to particular sciences, to the general method required 
 by general science or philosophy? Descartes would undoubt- 
 edly never have conceived such an audacious hope, had not a 
 great discovery of his set him on this track. He had invented 
 analytical geometry, or the method of expressing by means of 
 equations the properties of geometrical figures, or, inversely, 
 of representing determinate equations by means of geomet- 
 rical figures. In this way, Descartes substituted for the old 
 methods, which were especially adapted to algebra and geom- 
 etry as distinct branches, a general method, applicable to what 
 he called the "universal mathematical science," viz., to the 
 study of "the various ratios or proportions to be found be- 
 tween the objects of the mathematical 'sciences, hitherto re- 
 garded as distinct." Not only did this discovery mark a 
 decisive epoch in the history of mathematics, which it pro- 
 vided with an instrument of incomparable simplicity and 
 power, but it furthermore gave Descartes a right to hope 
 for the (philosophical method he was seeking. Ought not a 
 last generalization to be possible, by means of which the 
 method he had so happily discovered should become appli- 
 cable, not only to the "universal mathematical science," but 
 also to the systematic combination of all the truths which 
 our finite minds may permit us to attain? 
 
 Thus was formed in Descartes's mind the method which 
 he summed up in the Discours de la Méthode, and which was 
 destined in his plan to replace the useless and sterile ancient 
 logic . It is inexpedient here to explain these rules minutely. . 
 We must, however, observe that the first one, "Never to accept II 
 a thing as true which I do not clearly know to be such," is 
 not, properly speaking, a precept of method.! Such precepts 
 are set forth in a subsequent set of rules, where Descartes 
 successively prescribes analysis for dividing difficulties into 
 parts, and synthesis for constructing and expounding science. 
 But the first rule is quite different. It does not lay down a 
 process to be used in order to discover truth. It concerns 
 method only in so far as method is not separated from sci- 
 
xiv ESSAY ON DESCARTES. 
 
 \ ence itself (and such indeed was Descartes's meaning). If 
 I such is the case, the first step of method — or of science — must 
 be to determine accurately by what mark we can recognize 
 what is to be regarded as true, and what is to be set aside as 
 being only probable or dubious. This mark is what we call 
 evidence. This first rule may have been suggested to Des- 
 cartes, as the others were, by mathematics. Even as in his 
 method he generalized the processes used for mathematical 
 researches and demonstrations, so in this formula he laid 
 down the regulating principle to which this science owes its 
 perfection, and which was also to become the regulating prin- 
 j ciple of the new philosophy. 
 
 Thus the famous rule of "evidence" reaches far beyond the 
 ,' scope of a mere principle of method. Both from what it ex- 
 " eludes and what it implies, it may be looked upon as the 
 motto of the Cartesian philosophy. It rejects, to begin with, 
 any knowledge grounded upon authority alone (excepting the 
 truths of religion). Even though Aristotle and all his com- 
 mentators were agreed on one opinion, this would be no proof 
 of its being true; and should it really chance to be so, the 
 authority of Aristotle would count for nothing towards estab- 
 lishing its standing in science. Nothing can be admitted in 
 science but what is evident ; i. e., nothing but what is so clear 
 and plain as to leave no possible doubt, or is soundly deduced 
 I from principles which rest on such evidence. The whole 
 j system of scholasticism: metaphysics, logic, physics, thus 
 stand irretrievably condemned in toto. The so-called moral 
 sciences, which cannot attain to a degree of evidence com- 
 parable to that of mathematics, and which have to content 
 themselves with more or less strong probability, are likewise 
 rejected by the Cartesian formula; in fact, Descartes, as has 
 already been observed, had but little esteem for history and 
 erudition. 
 
 But what makes this rule of paramount importance is, that 
 it establishes reason as supreme judge of what is false or 
 true. Reason thus proclaims its own sovereign right to decide 
 without appeal. What we are to think, to believe, and to 
 do should be determined solely by evidence; and of that evi- 
 dence reason alone is judge (except in the case of urgency 
 
ESSAY ON DESCARTES. xv 
 
 compelling us to immediate action). It is true, reason being 
 identical in all men, that such truth as becomes evident to one 
 of them becomes so to all other men likewise. Therefore 
 the assent given to evidence by one mind is by implication 
 equivalent to the universal consent of mankind; so that the 
 individual reason which distinguishes between true and false 
 is precisely the universal feature in every man. 
 
 Nevertheless, Descartes felt the danger that lay in his 
 formula. He foresaw the very serious misunderstandings to 
 which it might give rise, and he endeavored to prevent these 
 by taking multifarious precautions. First of all, the truths 
 of religion are carefully set apart and withdrawn from the 
 criticism of reason. They do not fall under its jurisdiction. 
 It is not ours to examine them, but to believe them. Ac- 
 cording to Descartes, we must seek neither to adapt them to 
 our reason, nor to adapt our reason to them. They belong 
 to another domain. Then Descartes makes a distinction be- 
 tween the sphere of knowledge and that of conduct ; he sub- 
 mits to provisional ethics, which is to be replaced by defini- 
 tive ethics only when science is completed, that is to say, in 
 a still remote future. Moreover, even in the province of 
 speculative thought Descartes refrains from touching upon 
 political and social questions. He censures "those blundering 
 and restless humours" ever ready to propose unasked-for re- 
 forms. Thus, after moral and religious problems, political 
 problems in their turn are cautiously set aside. Where, then, 
 shall the absolute sovereignty of reason be exercised? In 
 philosophy, in abstract sciences, in physics ; in short, wherever 
 men generally have no other interest but that of pure truth. 
 
 Well-meant precautions these were, no doubt, but vain pre- 
 cautions, too. Let reason rule supreme over this apparently 
 limited province, and by degrees it will inyade the others. 
 If we allow it, as a principle, the right to decide without 
 appeal between falsehood and truth, it soon will admit of 
 no restrictions but those it sets of its own accord through 
 the works of a Kant or of an Auguste Comte. In fact, 
 French philosophy in the eighteenth century was in the main 
 an endeavor to apply the spirit of the Cartesian method to 
 the very objects: politics, ethics, religion, which Descartes 
 
xvi ESSAY ON DESCARTES. 
 
 had carefully set apart. By holding nothing as true until I 
 have evidence of its being so, do I not in advance deprive 
 all historical rights of the means of securing recognition; do 
 I not thereby summon all privileges, institutions, beliefs, and 
 fortunes to produce their title deeds before the bar of rea- 
 son? By solemnly paying homage to Descartes, the "As- 
 semblée Constituante" proved that the spirit of the Revolu- 
 tion was conscious of one of its chief sources. 
 
 Being now in possession of his method, did not Descartes 
 have all that was necessary to construct his philosophic sys- 
 tem with absolute mathematical certainty? No, for in 
 mathematics the foundation principles : axioms and defini- 
 tions, are so plain and evident that no reasonable mind will 
 question them. But philosophy had until his time been want- 
 ing in such principles, and the object which Descartes has 
 in view is precisely to establish them. 
 
 To attain this end, he first casts aside as false (at least 
 provisionally) all the opinions which he has hitherto held as 
 true, and which are only probable. In order to avoid tedious 
 enumerations, he proposes to consider opinions from the point 
 of view of their sources. "For instance," says he, "having 
 sometimes found my senses deceitful, I will distrust all 
 that they teach me. As I have sometimes erred with 
 regard to very simple reasoning, I will distrust the 
 results of even the most positive sciences. Lastly, I 
 may suppose that an evil genius, who is all-powerful, takes 
 delight in making me err, even when I believe I see the 
 truth most plainly. Therefore, by a voluntary effort, which 
 is always possible since I am free, I will suspend my judgment 
 even in cases where the evidence seems to me irresistible. 
 
 "Is there any proposition which is not affected by this 'hyper- 
 bolical' doubt? There is one, and one only. Let my senses 
 deceive me, let my reasonings be false, let an evil genius delude 
 me concerning things which appear to me most certain; if I 
 am mistaken, it is because I am — and this truth 'I think, there- 
 fore I am,' cogito, ergo sum,, is so self-evident and so certain 
 that the most extravagant doubt of skeptics is unable to 
 shake it." Here, then, is the first principle of philosophy 
 sought for by Descartes. And even as Archimedes asked only 
 
ESSAY ON DESCARTES. xvii 
 
 a standing-place to lift the world, so Descartes, having found 
 a quid inconcussum, an indisputable proposition, set to work 
 to erect his whole system upon this foundation. 
 
 However, if according to the custom of philosophers we dis- 
 tinguish the sphere of knowledge from that of existence, this 
 proposition, or, as it is called, Descartes's cogito, is certainly 
 first in the sphere of knowledge ; for I may have doubts about 
 whatever I may think, but about my thinking I can have no 
 doubt, even in the very moment when I doubt. But in the 
 sphere of existence the Absolute — that is, God — comes first. 
 Therefore Descartes, as soon as he had established the cogito, 
 turned to demonstrating the existence of God. He knows 
 that he thinks, but he also knows that he doubts, and therefore 
 that he is imperfect; for not knowing instead of knowing is 
 an imperfection. He therefore has an idea of perfection. 
 Whence comes this idea? Descartes examines all the con- 
 jectures which may be made as to its origin; he eliminates 
 them one after another as inadequate until one only remains, 
 viz., that the idea of perfection cannot have sprung from ex- 
 perience, that we could not have it if the all-perfect Being — 
 that is, God — did not actually exist, and that therefore this 
 idea is as "the stamp left by the workman upon his work." 
 
 Descartes was bound to demonstrate the existence of God 
 at the very outset. Otherwise, the supposition of an evil 
 genius, who was able to deceive him even when he conceived 
 things with perfect clearness, would have cast suspicion upon 
 all propositions but the cogito ; the doubt which he himself 
 had raised would have paralyzed him. In "order to do away 
 with such a supposition, Descartes at once proceeds to dem- 
 onstrate the existence of an all-perfect God, who cannot pos- 
 sibly wish to deceive us. But is not this a syllogistic circle? 
 If the plainest argument, in order to be accepted as valid, 
 needs the guaranty of God, what will guarantee the argument 
 intended to prove the existence of God? 
 
 A syllogistic circle, indeed, had not Descartes escaped from 
 it with the help of the following reasons : God's guaranty 
 is necessary, not for the sake of the evidence, which is quite 
 sufficient in itself so long as it lasts (whereof the cogito is a 
 proof) ; but in order to assure me of the truth of propositions 
 
xviii ESSAY ON DESCARTES. 
 
 which I remember having admitted as evident without remem- 
 bering for what reasons. It is necessary, in short, wherever 
 memory intervenes, but only in that case. Now if we have no 
 need of memory to know that we think, neither do we need 
 it to know that God exists. In spite of the syllogistic form 
 which Descartes gave to the proof of the existence of God, 
 this proof is rather intuitive than grounded on formal reason- 
 ing. In the act of conceiving the idea of the all-perfect Being, 
 I see at the same time the impossibility of His not existing. 
 The existence of all other things is looked upon as only pos- 
 sible ; but the existence of God appears as evidently necessary, 
 being comprised in the very notion of God. This is no argu- 
 ment, but rather an immediate apprehension. It is, as Male- 
 branche said shortly afterward, a proof "from mere vision." 
 The syllogistic circle therefore was only apparent. Descartes 
 was right in establishing the existence of God immediately 
 after the cogito. Henceforward he could in all confidence 
 make use of the faculties given him by God, who never de- 
 ceives. He only needed now to follow out his method care- 
 fully, and to link propositions together in the requisite order, 
 in order to arrive infallibly at the truth. 
 
 Now, the requisite order is, to begin with things which 
 are most general, simple and easy to grasp; that is, with the 
 primary principles from which the other truths are to be 
 deduced. Physics therefore is not to be studied until meta- 
 physics is well grounded. Acting upon this precept, Descartes 
 first established the existence of an absolute and perfect Being 
 — that is, God; for the same reason he now proceeds to 
 ascertain the essence of the soul and of the body. To reach 
 this end his starting-point is again the cogito. 
 
 I think, I am ; but what am I ? A creature that thinks ; that 
 is to say, judges, remembers, feels, imagines and wills; a being 
 whose existence is not linked to any place, nor dependent 
 upon any material thing. Descartes has just got out of his 
 universal doubt by means of the cogito. The only thing the 
 existence of which he can maintain at this point is his own 
 thought. Now, the existence of his thought does not appear 
 to him to be necessarily linked to that of his body and de- 
 pendent upon the latter. On the contrary, he may suppose 
 
ESSAY ON DESCARTES. xix 
 
 that his body does not exist and that the perception of the 
 external world and of his own members is an illusion. He 
 is even unable for the present to reject this supposition; he 
 cannot do so till later on, and even then with some difficulty. 
 Nevertheless, since he thinks, he is certain he exists. But, 
 conversely, let him for a moment suppose that he ceases to 
 think; upon this supposition he ceases to exist, although all 
 external bodies and his own body should remain real. There- 
 fore, the cognition of his own being, which is his thought, 
 by no means depends on material things, the existence of 
 which is still problematic. Therefore his whole nature is to 
 think. 
 
 "You suppose," some opponent said to Descartes, "that 
 your own body does not exist, and you say that nevertheless 
 you continue to think. But should your supposition prove 
 true — that is to say, should your body and your brain be dis- 
 solved — can you affirm that even then you would continue to 
 think?" To which Descartes answered: "I do not assert 
 this — at least not now. My present object is not to demon- 
 strate the immortality of the soul. This is a metaphysical 
 question I am not now able to solve — for I know only one 
 fact as yet, viz., that I think (and also that God exists). The 
 whole question I am examining is merely : 'What am I ?' 
 Now it appears from what has been said that my existence is 
 known to me as that of a being endowed with thought and 
 endowed only with thought; for, whilst I am as certain as 
 possible of the existence of my thought, the existence of any- 
 thing else is still wholly doubtful to me. The existence of 
 this thought may possibly be actually connected with that of 
 the brain. I know nothing about that. I am not discussing 
 that for the present. One thing is certain : I know myself 
 as a thought, and I positively do not know myself as a brain." 
 
 This is one of the leading features of the philosophy of 
 Descartes, and one which may enable us to measure his influ- 
 ence, by comparing what had been thought before him with 
 what was thought after him. The cogito of Descartes dis- 
 placed, so to speak, the axis of philosophy. To the ancients 
 and to the scholastics (theology excepted) the thinking mind 
 appeared inseparable from the universe, regarded as the object 
 
xx ESSAY ON DESCARTES. 
 
 of its thought, just as the soul itself was conceived to be the 
 "substantial form" of the living body. According to Descartes, 
 on the contrary, the existence of the thinking mind, far from 
 being dependent on any other existing thing, is the essential 
 condition of every other existence conceivable to us ; for if I 
 am certain of the existence of anything but myself, with far 
 better reason am I certain that I, who have that thought, am 
 in existence. The only reality I cannot possibly question is 
 that of my own thought. 
 
 Both the adversaries and the successors of Descartes started 
 from this point. All the modern forms of idealism, so utterly 
 different from the idealism of the ancients, have a common 
 origin in the cogito. The tempered and prudent idealism of 
 Locke, the Christian idealism of Malebranche, the skeptical 
 idealism of Hume, the transcendental idealism of Kant, the 
 absolute idealism of Fichte and many other doctrines derived 
 from these, which have appeared in our century, are all more 
 or less closely related to the foundation principle of the Car- 
 tesian philosophy. Moreover, the conception of nature in 
 modern science must also be connected with it. For, as we 
 shall see farther on, when Descartes set thought — that is, the 
 soul — so distinctly apart from everything extraneous to itself, 
 in so doing he made necessary a new conception of force and 
 life in the material world. 
 
 Now, let us add to the Cartesian formula, "I am a thing 
 which thinks," the following principle, "All that I conceive 
 clearly and distinctly is true." Then, since I conceive clearly 
 and distinctly that the nature of the body and that of the soul 
 have no attributes in common, therefore it is true that these 
 two natures or substances are separated one from the other. 
 Not only is there no need of my having any notion of the 
 body in order to comprehend the soul, but also the soul has 
 no need of the body in order to exist. 
 
 Descartes, therefore, had a right to infer that "the soul is 
 more easily known than the body." This does not mean that, 
 according to his doctrine, psychology is an easier science than 
 physics or physiology. Psychology as we conceive it has no 
 place in the system of Descartes; there is at most a mere 
 sketch of it in the Passions de l' Ame. But this maxim is 
 
ESSAY ON DESCARTES. xxi 
 
 metaphysical, not psychological. It means that there is no 
 more evident knowledge than that which the soul has of itself, 
 since there is none which it is more impossible to doubt; that 
 the body, on the contrary, is known only representatively, and 
 that, far from our being unable to doubt its existence, we 
 cannot overcome such a doubt, when once raised, save by 
 means of laborious and complicated reasonings. 
 
 In order to make all this clearer still, let us remember Des- 
 cartes's oft-repeated caution to "cast off all the impressions of 
 the senses and imagination and trust to reason alone." There 
 are not two kinds of evidence : one which tells us that the 
 sun shines, that honey is sweet, that lead is heavy; and an- 
 other which informs us that if equals be added to equals the 
 sums are equal. Only the latter proposition is self-evident; the 
 former statements, in spite of any prepossession to the con- 
 trary, are not so. The impressions of the senses are vivid, 
 but confused; we cannot account for them, and nothing can 
 warrant them to be true. The water which is warm to me 
 seems cold to you. Cold and heat, as well as all other qualities 
 pertaining to bodies, with the exception of extension, are not 
 inherent in them; they are relative to the sentient subject. 
 Therefore, if we think we know bodies by what our senses 
 teach us of them, we fall into error, as will happen every 
 time when, through overhastiness or prejudice, we form a 
 judgment before the evidence is complete. For can I not 
 have in a dream all the perceptions I now have and be as 
 firmly persuaded of their reality? But whether I am dreaming 
 or waking it is true that two and two are four, and it is true 
 that I, who think so, am in existence. 
 
 Thus, previous to philosophical reflection, nothing seems to 
 us so well known as the body and its qualities, because we 
 form images of them continually and without any difficulty; 
 whereas it is not easy for us to realize what the soul is, seeing 
 that it is not an object for the imagination to grasp. The 
 first task of the philosopher consists precisely in disengaging 
 himself from the false light of the senses and seeking the true 
 light of reason. It is an effort akin to the one demanded by 
 Plato, when he termed philosophy the science of the invisible, 
 and recommended the study of mathematics as a preparatory 
 
xxii ESSAY ON DESCARTES. 
 
 training. The body and the organs of the senses, far from 
 making us acquainted with what really is, are a hindrance 
 to the proper activity of the mind. Even matter, which we 
 fancy our hands, eyes, ears, etc., can apprehend immediately, 
 we really know only by means of our understanding. For 
 the latter alone can give us a distinct notion of it, viz., the 
 notion of a thing measurable in length, breadth and depth. 
 
 The other qualities of bodies are not really inherent in them. 
 "Look at this piece of wax; it has just been taken from the 
 hive ; it has not yet lost the sweetness of the honey it con- 
 tained; it still retains something of the fragrance of the flow- 
 ers from which it was gathered; its color, figure and size are 
 apparent; it is hard, cold, easily handled, and if you strike it 
 will give forth some sound. * * * But now, while I am 
 speaking, somebody brings it near the fire; whatever taste 
 remained in it is exhaled, the odor evaporates, its color 
 changes, its shape is lost, its size increases, it becomes liquid, 
 it is warmer, one can hardly handle it, and when we strike it, 
 it will no longer give forth a sound." And yet the same wax 
 is there. Therefore this wax was neither the honey-sweet 
 flavor, nor the pleasant flowery smell, nor the whiteness, nor 
 the form, nor the sound, but merely a body which, a short 
 time before, was apparent to my senses under these forms, 
 but now presents itself under other forms. Therefore all I 
 can conceive clearly and distinctly about this body is its ex- 
 tension. 
 
 Descartes's definition of the soul is "a thing that thinks" ; 
 of the body, "a thing that has extension." This doctrine is 
 strangely at variance with the metaphysics taught in his time. 
 The scholastic philosophers, who on this point followed the 
 teaching of Aristotle, regarded the soul as both the principle 
 of life and the principle of thought. The same soul which in 
 plants is purely nutritive, becomes locomotive, then sensitive 
 in animals, and lastly, in man, rational. And though such a 
 doctrine made the immortality of the soul a difficult thing to 
 conceive, it was no cause of embarrassment to the schoolmen, 
 for immortality to them was an object of faith, not of dem- 
 onstration. There is neither a nutritive nor a locomotive soul, 
 says Descartes. There is but one kind of soul, which is the 
 
ESSAY ON DESCARTES. xxiii 
 
 thinking soul, for feeling is thinking. Nutrition and locomo- 
 tion are explainable simply by the laws of mechanics. Ani- 
 mals, which do not think, do not feel either. They may be 
 looked upon as automatons, and the perfection of some of 
 their actions may be compared to the perfection of the work- 
 ings of a clock. After this we can no longer suppose that 
 the destiny of man after death is the same as that of flies 
 and ants. 
 
 Scholastic physics likewise assumed the existence of forces 
 and occult causes inherent in matter, and thought the specific 
 nature of certain natural phenomena could not otherwise be 
 accounted for. Here again Descartes adopts the reverse of 
 their doctrine, rejecting in toto these assumed principles, 
 forces and causes, which to him are but confused notions, 
 hypotheses convenient to sluggish minds, explanations which 
 explain nothing, but merely repeat the enunciation of the 
 problem under another form. Given matter, that is, extension 
 as considered by geometricians, he wants no other data than 
 number, motion and duration. These are sufficient, he con- 
 siders, to account for all the phenomena which take place in 
 bodies either inorganic or living. 
 
 Thus Descartes's physical science is purely rational in char- 
 acter and in scrupulous accordance with the rule of his 
 method which forbids him to "accept anything as true unless 
 it appears by evidence to be so." It tends to assume a geo- 
 metrical form, and all questions of physics are reduced, at 
 least in principle, to problems of mechanics. "Give me matter 
 and the laws of motion," says Descartes, "and I will build a 
 universe exactly like the one that we behold, with skies, stars, 
 sun and earth, and on the earth minerals, plants and animals ; 
 in short, everything that experience introduces to us, except 
 the rational soul of man." 
 
 No doubt Descartes imagined all natural phenomena, and 
 in particular those of animated beings, to be less complicated 
 than they really are. His conceptions are those of a great 
 mathematician, living at a time when physics and chemistry 
 hardly existed and when biology did not exist at all. He 
 thinks he can determine a priori the number of the fixed stars. 
 He imagines he can describe accurately the formation of the 
 
xxiv ESSAY ON DESCARTES. 
 
 foetus. He hopes, by taking due care of the human machine 
 and by repairing it when necessary, to protract the life of 
 man indefinitely, to conquer disease and even death. Scientific 
 men in our days are better acquainted with the difficulties of 
 such problems and are consequently less pretentious. But the 
 scientific ideal they aim at, though indefinitely removed from 
 that which we are considering, has remained pretty much the 
 same as Descartes conceived it : to discover the laws of every 
 phenomenon by reducing them, as far as possible, to number 
 and measure, and to discard every metaphysical hypothesis 
 meant to explain any class of physical phenomena. 
 
 This geometrical conception of the material universe was 
 repeatedly attacked by the successors of Descartes. Leibniz 
 endeavored to prove that the Cartesian definition of matter 
 was incompatible with the laws of motion. Leibniz is fond 
 of connecting Democritus and Descartes, and is wont to quote 
 them together. The parallel is an ingenious one, but should 
 not be followed up too closely. No doubt Descartes, like 
 Democritus, requires only matter and motion in order to 
 explain the genesis of the physical universe. But, to say 
 nothing of the very considerable differences between the ex- 
 planation of Democritus and that of Descartes, can anyone 
 forget that the physical science of Democritus and his meta- 
 physics are all one and the same thing? Atoms and vacuum 
 are to him the primal elements of all things, and, as was 
 objected to him by Aristotle, he does not take the trouble 
 even to explain the origin of motion. With Descartes, before 
 physics is begun a complete metaphysical system has first been 
 established, and it is from this that physics is to derive its 
 principles : the primordial laws of phenomena (for instance, 
 that light propagates itself in straight lines) are deduced from 
 God's attributes. Moreover, Descartes is not compelled by 
 his system, as Democritus is, to deny the existence of final 
 causes. On the contrary, he maintains their existence. It is 
 true that he forbids us to seek them out, but the reason is 
 that, according to him, it would be highly presumptuous in us 
 mortals to try to comprehend God's designs; the more so as 
 God's liberty is absolute and infinite, and since, in consequence, 
 His acts may be wholly unintelligible to our reason. And 
 
ESSAY ON DESCARTES. xxv 
 
 lastly, far from looking upon matter as self-existent, Descartes 
 believes that bodies, as well as all other finite things, exist only 
 by God's express will and constant help. Should this help 
 cease for an instant all bodies would at once sink back into 
 nothingness. 
 
 The mechanical character of Descartes's system, if mechan- 
 ical it be, is therefore far removed from the materialism of 
 Democritus. Descartes firmly maintained the reality of free- 
 will, to which he ascribes an essential part in his theory of 
 judgment and of error. It is only as physicist, not as philoso- 
 pher, that Descartes may be termed mechanical. But in this 
 sense nearly all men of science are so, too ; for, to use F. A. 
 Lange's striking expression : "Mechanism is an excellent 
 formula for the science of nature." 
 
 But is not, however, the strictly deductive science con- 
 ceived by Descartes very remote from the modern science of 
 nature, which employs the experimental method with so much 
 zeal and success? True, Descartes often thought deduction 
 easy when it was difficult, and possible when it was imprac- 
 ticable. But this was a question of fact, not of principle. As 
 this or that branch of science (at least, of physical science) 
 is gradually brought nearer to perfection, we see it grow from 
 the experimental into the rational. Such has long been the 
 case with astronomy and celestial mechanics, and later, suc- 
 cessively with optics, with acoustics, with hydrodynamics, with 
 the theory of heat and electricity and other fields of physics, 
 all so many confirmations of the Cartesian ideal. 
 
 Moreover, Descartes himself assigned an important rôle to 
 the experimental method. Anecdotes depict him to us as ris- 
 ing very early, in Amsterdam, in order to choose in a butcher's 
 shop the joints he wished "to anatomize at leisure"; or an- 
 swering an inquirer who wished to see his library, "Here it 
 is," at the same time pointing to a quarter of veal which 
 he was busily dissecting. In the last years of his life he de- 
 voted only a few hours a year to mathematics, and not much 
 more to metaphysics. He busied himself almost exclusively 
 with experiments in physics and physiology. How could he 
 have failed to appreciate the importance of a method which 
 he was himself so assiduously putting into practice? 
 
xxvi ESSAY ON DESCARTES. 
 
 "Anticipating causes with effects," is Descartes's felicitous 
 definition of experimenting. It clearly shows the functions he 
 ascribed to it. Were there only one way in which a certain 
 effect might be deduced from given causes, experimenting 
 would be unnecessary. But natural phenomena are so com- 
 plex, and the possible combinations of causes are so numer- 
 ous, that we may nearly always explain in several ways the 
 production of a given effect. Which is the right way? Ex- 
 periment alone can decide. Let us make a distinction between 
 science already developed and science which is developing. 
 To expound a developed science the suitable method is de- 
 duction, — descent from causes to effects. But science which 
 is developing cannot yet adopt this method; and to discover 
 unknown laws, it must employ the experimental method, must 
 anticipate causes with effects. 
 
 Descartes had written a Traite du Monde and was about to 
 publish it, when the condemnation of Galileo for heresies 
 concerning the motion of the earth altered his resolution. 
 Being, above all, desirous to work in peace, and to postpone 
 as long as he could a perhaps inevitable conflict with the 
 theologians, he published only a few fragments of his physical 
 theories, and put a summary sketch of it into the admirable 
 fifth part of the Discours de la Méthode. We must certainly 
 deplore the loss of this great work, which would throw light 
 upon many an obscure point in the Cartesian philosophy. But, 
 after all, the essential part of the doctrine did not lie here, 
 any more than in the well-known hypothesis of "vortices," 
 which the Cartesian philosophers of the eighteenth century 
 vainly tried to set up in opposition to the principle of universal 
 gravitation discovered by Newton, and with which some 
 physicists now partly agree in their theories of matter. 
 
 The main interest lies elsewhere, viz., in the perfect charac- 
 ter of the science of nature, of which Descartes had such a 
 clear and precise notion, even though he was far from being 
 able to put it into practice save in a few points (for instance, 
 by his discoveries in optics). It is said that the man who in- 
 vented the plough still walks, invisible, beside the peasant 
 who drives his own plough in our days. I might almost say 
 that, in our laboratories, Descartes stands invisible and près- 
 
ESSAY ON DESCARTES. xxvii 
 
 ent, investigating with our scientific men the laws of phe- 
 nomena. 
 
 If he had lived, would he have passed on from the sciences of 
 life to the ethical and social sciences, as he had done already 
 from mathematics to physics, and from physics to anatomy 
 and physiology? This may be doubted. To say nothing of 
 considerations of prudence, to which Descartes was most sus- 
 ceptible, he held in slight esteem the visionaries and political 
 reformers of the sixteenth century, and would have been 
 sorely vexed if any comparison had been drawn between 
 their fancies and his own doctrines. On the other hand, he 
 could not but find it extremely difficult to make social facts 
 fall in with his method, since, as Auguste Comte very aptly 
 observed, so long as biology is not sufficiently advanced, social 
 science must needs be out of the question. Now, in the time 
 of Descartes, biology was still unborn. Even ethics he does 
 not seem to have taken into deep consideration. He borrows 
 the rules of his provisional ethics from Montaigne and from 
 the Stoics. Stoicism, modified in some respects, also forms 
 the fundamental part of Descartes's moral letters to Princess 
 Elizabeth. It is a peculiarity of French philosophy, that it has 
 produced many moralists and few moral theorists. The rea- 
 son for this we shall seek elsewhere. Certain it is that Des- 
 cartes was not one of these theorists. Perhaps he believed 
 that scientific ethics (ethics not grounded on religious author- 
 ity) could not be established till the science of man was estab- 
 lished, and the connection of the physical and the moral better 
 known. To this knowledge he opened the way in his Traite 
 des Passions de l'Ame. 
 
 All the precautions taken by Descartes, all his prudence, did 
 not shield him from the attacks his philosophy was to bring 
 upon him, as being "subtle, enticing, and bold." After hes- 
 itating a long while, the Jesuits, by whom he had been 
 brought up at La Flèche, and among whom he had still some 
 friends, declared themselves against his philosophy. The sev- 
 enth series of Objections, by Father Bourdin, express the 
 opinion of this society. Descartes wrote a vigorous reply. 
 His quarrel with the Jesuits was one of his motives for not 
 living in France. He established himself in Holland, where 
 
xxviii ESSAY ON DESCARTES. 
 
 he lived a long while in undisturbed peace. But as his philos- 
 ophy spread, attention was drawn to him, and as the univer- 
 sities of the country were beginning to quarrel about his 
 theories, he felt that his life there would soon become unbear- 
 able. He therefore resolved to yield to the entreaties of 
 Queen Christina, who earnestly urged him to come to Sweden. 
 But he could not endure the severe climate of that country, 
 and hardly six months had elapsed when he died of inflam- 
 mation of the lungs. Later, his body was brought back to 
 France. 
 
 The philosophy of Descartes was in accord with the lead- 
 ing tendencies of his time. The success which attended it 
 from the moment it appeared is a proof of its opportune- 
 ness, and it is difficult to determine whether it formed, rather 
 than expressed, the spirit of the age. Doubtless it did both. 
 As has been said, the seventeenth century in France was pre- 
 eminently the "age of reason." 
 
 Aimez donc la raison ; que toujours vos écrits, 
 Empruntent d'elle seule et leur lustre et leur prix, 
 said Boileau ; yet perhaps, had it not been for the Cartesian 
 philosophy, this taste for reason might not have asserted itself 
 so earnestly and have been so perfectly conscious of its exist- 
 ence. 
 
 This philosophy of "clear ideas" prevailed in France in the 
 second half of the seventeenth century, and from France its 
 influence spread over all Europe. Though vigorously attacked 
 in the eighteenth century, both as to its metaphysics and its 
 physics, it nevertheless remained discernible even in the meth- 
 ods of its adversaries. Locke, Hume, and Condillac had not 
 the same conception of evidence as Descartes ; but their empir- 
 icism was as fond of clearness as his rationalism had been. 
 Newton combated the hypothesis of "vortices," but he pre- 
 served the Cartesian notion of a mechanical explanation of 
 physical phenomena. For a thorough-going and express ne- 
 gation of the Cartesian spirit we must go to the end of the 
 eighteenth century. Then the German romantic writers spring 
 up, and maintain that the philosophy of clear ideas is false 
 from its very principle. According to them, reality is not 
 clear, and the more satisfactory a doctrine is to the human 
 
ESSAY ON DESCARTES. xxix 
 
 understanding, the surer it is to reproduce only the surface of 
 things, while the essence of them is mysterious, intangible 
 and inexpressible. Whence it follows that religions, arts and 
 literatures are spontaneous philosophies, incomparably deeper 
 than the systems produced by the conscious labor of the un- 
 derstanding, even as the works of nature are artistically 
 superior to the articles manufactured by man. 
 
 The philosophy of Descartes, to tell the truth, affords but 
 little scope to sentiment, and still less to the imagination and 
 to the hidden and unconscious activities of the mind. It places 
 value on evidence alone, whose vivid, but glaring light, dispels 
 the chiaroscuro so dear to romantic writers. This fixed and 
 rigid purpose has its drawbacks, which were not long in mak- 
 ing their appearance among the followers of Descartes. 
 
 But apart from the fact that in Descartes himself the 
 rational effort was uncommonly sincere and vigorous, at the 
 time when this philosophy appeared it was really necessary. 
 It was a deliverer. It put an end to superannuated doctrines, 
 the domination of which was still heavily felt. It cleared 
 the ground, and set physics free, once for all, from the clogs 
 of metaphysical hypotheses. Lastly, it formulated problems 
 which needed formulation. Descartes wished to furnish 
 science not only with a powerful and flexible instrument such 
 as Bacon had already sought, but also with an unchanging 
 and immovable basis. Thence sprang the "provisional 
 doubt," with which his method bids him begin, which obliges 
 him to test all previously acquired information, and which 
 may be looked upon as the starting-point of all modern 
 theories of knowledge. For this doubt, which affects suc- 
 cessively perception, imagination, reasoning power, and stops 
 only before the immediate self-intuition of thought, is itself a 
 criticism of the faculty of knowledge. It studies it in its con- 
 nection both with the outward object and with the very mind 
 which is thinking ; in short, it heralds Kant's Critique of Pure 
 Reason. 
 
 An innovating and fruitful doctrine nearly always develops 
 in various directions. The various minds that receive it 
 gradually draw from it diverse and sometimes contradictory 
 conclusions, most of which were overlooked and would often 
 have been disapproved of by the founder of the system. This 
 
xxx ESSAY ON DESCARTES. 
 
 is perhaps even truer of Descartes than of any other philoso- 
 pher. Being chiefly preoccupied with the method and struc- 
 ture of science, he did not hesitate to leave open, at least 
 temporarily, many important questions which his method did 
 not require him to solve immediately. Thus it happened that 
 metaphysical systems very different from one another were 
 soon founded on the Cartesian principles. Spinoza adopted 
 the definition which Descartes had given of soul and matter, 
 but in thought and extension he saw only two attributes of one 
 and the same substance. Beside this pantheism, appeared the 
 idealism of Malebranche, which proceeds no less directly from 
 Descartes; for did not the latter say that "truth is the same 
 thing as being?" And does not the theory of continued crea- 
 tion lead directly to that of occasional causes? Locke, who 
 combated Descartes on the subject of innate ideas, without 
 understanding him exactly, has on the other hand many points 
 in common with him ; the very idea of inventorying and exam- 
 ining the ideas in our minds is singularly akin to the critical 
 examination of our knowledge which, in Descartes, precedes 
 the cogito. And lastly, into the idealism of Leibniz the Car- 
 tesian element enters in large measure; for instance, the 
 notion of sensation being but a dim intellection, which is the 
 central point of Leibniz's theory of knowledge, had already 
 been clearly stated by Descartes. 
 
 The philosophy of Descartes is therefore a sort of cross- 
 road whence diverge the chief ways followed by modern 
 thought. Still, outside of France, his method has not been 
 followed without restrictions, and his philosophy has been 
 accepted only to be immediately combined with other elements 
 either traditional or modern. In France, the influence has 
 been far deeper and more enduring. There, while the Car- 
 tesian philosophy may have lost its prestige rather quickly, the 
 Cartesian spirit, owing, doubtless, to its close affinity with the 
 very genius of the nation, has never disappeared, and we 
 shall recognize its influence, not only throughout the whole 
 eighteenth century and in the French Revolution, but in all 
 the greatest thinkers of the nineteenth century. 
 
CONTENTS, 
 
 PAGE 
 
 Publishers' Preface iii 
 
 Essay on the Philosophy of Descartes by Prof. L. Levy- 
 
 Bruhl vii 
 
 Title-pages of the original editions xxxi 
 
 L— THE MEDITATIONS. 
 
 Dedication i 
 
 Preface 9 
 
 Synopsis of the Meditations 15 
 
 Meditation I. 
 Of the Things of which we may Doubt 21 
 
 Meditation II. 
 
 Of the Nature of the Human Mind ; and that it is more 
 easily known than the Body 29 
 
 Meditation III. 
 Of God ; that he exists 42 
 
 Meditation IV. 
 Of Truth and Error 63 
 
 Meditation V. 
 
 Of the Essence of Material Things ; and, again, of God : 
 that he exists 75 
 
 Meditation VI. 
 
 Of the Existence of Material Things, and of the Real 
 Distinction between the Mind and Body of Man 84 
 
CONTENTS. 
 IL— THE PRINCIPLES OF PHILOSOPHY. 
 
 PAGE 
 
 Preface 107 
 
 Dedication 126 
 
 Part I. 
 Of the Principles of Human Knowledge 130 
 
 Part II. 
 Of the Principles of Material Things. Sects, i. to xxv. . 175 
 
 Part III. 
 Of the Visible World. Sects, i. to iii. — 192 
 
 Part IV. 
 
 Of the Earth. Sects, clxxxviii. to ccvii 194 
 
 Appendix 215 
 
 Notes 224 
 
 Bibliography 249 
 
THE MEDITATIONS 
 
 N>F 
 
 DESCARTES 
 
 TRANSLATED FROM THE LATIN AND COL- 
 LATED WITH THE FRENCH. 
 
Renati Des-Cartes Mitaines 
 de Frima Fhilosopbia 
 
 In qua del existentia et animœ 
 immortalitas iemonstratur. 
 
 PARISIIS 
 
 Apud Michaelem Soly, via Jacobeâ, sub signo Phœnicis. 
 
 MDCXLI. 
 
 Cum Privilegio et Approbatione Doctorum. 
 Vignette: a phoenix with the inscription, „Aeternitatl soli". 
 
Benati Dès-Cartes leditationes 
 
 In quibus Dei existentia, & animœ humanœ 
 a corpore distinctio demonstratur. 
 
 His adjunctsesunt varise objectiones doctorum virorum 
 in istas de Deo & anima demons trationes. 
 
 Cum responsionibus AuthorU. 
 
 Secunda editio septimis objectionibus antehac non 
 visis aucta. 
 
 AMSTELODAMI, 
 Apud IyUdovicum Elzevirium, 1642. 
 
 Vignette: Minerva beneath an olive tree: „Ne extra oleas". 
 
LES 
 
 Meditations Métaphysiques 
 de René Des=Cartes 
 
 TOUCHANT LA PREMIERE PHILOSOPHIE 
 
 dans lesquelles l'existence de Dieu, & la distinction 
 
 réelle entre l'âme & le corps de l'homme, 
 
 sont demonstrées. 
 
 Traduites du Latin de V Auteur par 
 M. le D. D. L. N. 8. 
 
 Et les objections faites contre ces Méditations par 
 
 diverses personnes tres-doctes, avec les réponses 
 
 de l'Auteur. 
 
 Traduites par Mr, C. L. B. 
 
 A PARIS. 
 
 Chez la Veuve Jean Camusat, 
 
 ET 
 
 Pierre le Petit, rue S. Jacques, 
 
 à la Toyson d'Or. 
 
 M. DC. XL. VII. 
 AVEC PRIVILEGE DU ROY. 
 
 Vignette: Jason with the golden fleece and the dragon: „Tegltet quo» 
 ""■ naurat". 
 
TO 
 
 THE VERY SAGE AND ILLUSTRIOUS 
 THE 
 
 DEAN AND DOCTORS OF THE SACRED 
 FACULTY OF THEOLOGY OF PARIS. 
 
 Gentlemen, 
 The motive which impels me to present this Treatise 
 to you is so reasonable, and, when you shall learn its 
 design, I am confident that you also will consider that 
 there is ground so valid for your taking it under your 
 protection, that I can in no way better recommend it 
 to you than by briefly stating the end which I pro- 
 posed to myself in it. I have always been of opinion 
 that the two questions respecting God and the Soul 
 were the chief of those that ought to be determined 
 by help of Philosophy rather than of Theology; for 
 although to us, the faithful, it be sufficient to hold as 
 matters of faith, that the human soul does not perish 
 with the body, and that God exists, it yet assuredly 
 seems impossible ever to persuade infidels of the real- 
 ity of any religion, or almost even any moral virtue, 
 unless, first of all, those two things be proved to them 
 by natural reason. And since in this life there are 
 frequently greater rewards held out to vice than to 
 virtue, few would prefer the right to the useful, if they 
 were restrained neither by the fear of God nor the ex- 
 
2 DEDICATION. 
 
 pectation of another life ; and although it is quite true 
 that the existence of God is to be believed since it is 
 taught in the sacred Scriptures, and that, on the other 
 hand, the sacred Scriptures are to be believed because 
 they come from God (for since faith is a gift of God, 
 the same Being who bestows grace to enable us to be- 
 lieve other things, can likewise impart of it to enable 
 us to believe his own existence), nevertheless, this 
 cannot be submitted to infidels, who would consider 
 that the reasoning proceeded in a circle. And, indeed, 
 I have observed that you, with all the other theolo- 
 gians, not only affirmed the sufficiency of natural rea- 
 son for the proof of the existence of God, but also, 
 that it may be inferred from sacred Scripture, that the 
 knowledge of God is much clearer than of many 
 created things, and that it is really so easy of acquisi- 
 tion as to leave those who do not possess it blame- 
 worthy. This is manifest from these words of the 
 Book of Wisdom, chap, xiii., where it is said, Howbeit 
 they are not to be excused; for if their understanding 
 was so great that they could discern the zvorld and the 
 creatures, why did they not rather find out the Lord 
 thereof ? And in Romans, chap, i., it is said that they 
 are zvithout excuse; and again, in the same place, by 
 these words, — That which may be known of God is 
 manifest in them — we seem to be admonished that all 
 which can be known of God may be made manifest by 
 reasons obtained from no other source than the in- 
 spection of our own minds. I have, therefore, thought 
 that it would not be unbecoming in me to inquire how 
 and by what way, without going out of ourselves, God 
 may be more easily and certainly known than the 
 things of the world. 
 
DEDICATION. 3 
 
 And as regards the Soul, although many have 
 judged that its nature could not be easily discovered, 
 and some have even ventured to say that human rea- 
 son led to the conclusion that it perished with the 
 body, and that the contrary opinion could be held 
 through faith alone; nevertheless, since the Lateran 
 Council, held under Leo X. (in session viii.), con- 
 demns these, and expressly enjoins Christian philoso- 
 phers to refute their arguments, and establish the 
 truth according to their ability, I have ventured to at- 
 tempt it in this work. Moreover, I am aware that 
 most of the irreligious deny the existence of God, and 
 the distinctness of the human soul from the body, for 
 no other reason than because these points, as they al- 
 lege, have never as yet been demonstrated. Now, al- 
 though I am by no means of their opinion, but, on the 
 contrary, hold that almost all the proofs which have 
 been adduced on these questions by great men, pos- 
 sess, when rightly understood, the force of demonstra- 
 tions, and that it is next to impossible to discover new, 
 yet there is, I apprehend, no more useful service to be 
 performed in Philosophy, than if some one were, once 
 for all, carefully to seek out the best of these reasons, 
 and expound them so accurately and clearly that, for 
 the future, it might be manifest to all that they are 
 real demonstrations. And finally, since many persons 
 were greatly desirous of this, who knew that I had 
 cultivated a certain Method of resolving all kinds of 
 difficulties in the sciences, which is not indeed new 
 (there being nothing older than truth), but of which 
 they were aware I had made successful use in other 
 instances, I judged it to be my duty to make trial of it 
 also on the present matter. 
 
4 DEDICATION. 
 
 Now the sum of what I have been able to accom- 
 plish on the subject is contained in this treatise. Not 
 that I here essayed to collect all the diverse reasons 
 which might be adduced as proofs on this subject, for 
 this does not seem to be necessary, unless on matters 
 where no one proof of adequate certainty is to be had ; 
 but I treated the first and chief alone in such a man- 
 ner that I should venture now to propose them as 
 demonstrations of the highest certainty and evidence. 
 And I will also add that they are such as to lead me to 
 think that there is no way open to the mind of man by 
 which proofs superior to them can ever be discovered ; 
 for the importance of the subject, and the glory of 
 God, to which all this relates, constrain me to speak 
 here somewhat more freely of myself than I have been 
 accustomed to do. Nevertheless, whatever certitude 
 and evidence I may find in these demonstrations, I 
 cannot therefore persuade myself that they are level 
 to the comprehension of all. But just as in geometry 
 there are many of the demonstrations of Archimedes, 
 Apollonius, Pappus, and others, which, though re- 
 ceived by all as highly evident and certain (because in- 
 deed they manifestly contain nothing which, consid- 
 ered by itself, it is not very easy to understand, and 
 no consequents that are inaccurately related to their 
 antecedents), are nevertheless understood by a very 
 limited number, because they are somewhat long, and 
 demand the whole attention of the reader: so in the 
 same way, although I consider the demonstrations of 
 which I here make use, to be equal or even superior 
 to the geometrical in certitude and evidence, I am 
 afraid, nevertheless, that they will not be adequately 
 understood by many, as well because they also are 
 
DEDICATION. 5 
 
 somewhat long and involved, as chiefly because they 
 require the mind to be entirely free from prejudice, 
 and able with ease to detach itself from the commerce 
 of the senses. And, to speak the truth, the ability for 
 metaphysical studies is less general than for those of 
 geometry. And, besides, there is still this difference 
 that, as in geometry, all are persuaded that nothing is 
 usually advanced of which there is not a certain dem- 
 onstration, those but partially versed in it err more 
 frequently in assenting to what is false, from a desire 
 of seeming to understand it, than in denying what is 
 true. In philosophy, on the other hand, where it is 
 believed that all is doubtful, few sincerely give them- 
 selves to the search after truth, and by far the greater 
 number seek the reputation of bold thinkers by auda- 
 ciously impugning such truths as are of the greatest 
 moment. 
 
 Hence it is that, whatever force my reasonings may 
 possess, yet because they belong to philosophy, I do 
 not expect they will have much effect on the minds of 
 men, unless you extend to them your patronage and 
 approval. But since your Faculty is held in so great 
 esteem by all, and since the name of Sorbonne is of 
 such authority, that not only in matters of faith, but 
 even also in what regards human philosophy, has the 
 judgment of no other society, after the Sacred Coun- 
 cils, received so great deference, it being the universal 
 conviction that it is impossible elsewhere to find greater 
 perspicacity and solidity, or greater wisdom and in- 
 tegrity in giving judgment, I doubt not, — if you but 
 condescend to pay so much regard to this Treatise as 
 to be willing, in the first place, to correct it (for, mind- 
 
6 DEDICATION. 
 
 fui not only of my humanity, but chiefly also of my 
 ignorance, I do not affirm that it is free from errors) ; 
 in the second place, to supply what is wanting in it, to 
 perfect what is incomplete, and to give more ample il- 
 lustration where it is demanded, or at least to indicate 
 these defects to myself that I may endeavour to rem- 
 edy them; and, finally, when the reasonings contained 
 in it, by which the existence of God and the distinction 
 of the human soul from the body are established, shall 
 have been brought to such degree of perspicuity as to 
 be esteemed exact demonstrations, of which I am as- 
 sured they admit, if you condescend to accord them 
 the authority of your approbation, and render a pub- 
 lic testimony of their truth and certainty, — I doubt 
 not, I say, but that henceforward all the errors which 
 have ever been entertained on these questions will 
 very soon be effaced from the minds of men. For 
 truth itself will readily lead the remainder of the in- 
 genious and the learned to subscribe to your judg- 
 ment; and your authority will cause the atheists, who 
 are in general sciolists rather than ingenious or 
 learned, to lay aside the spirit of contradiction, and 
 lead them, perhaps, to do battle in their own persons 
 for reasonings which they find considered demonstra- 
 tions by all men of genius, lest they should seem not 
 to understand them ; and, finally, the rest of mankind 
 will readily trust to so many testimonies, and there 
 will no longer be any one who will venture to doubt 
 either the existence of God or the real distinction of 
 mind and body. It is for you, in your singular wis- 
 dom, to judge of the importance of the establishment 
 of such beliefs, [who are cognisant of the disorders 
 
DEDICATION. 7 
 
 which doubt of these truths produces] .* But it would 
 not here become me to commend at greater length the 
 cause of God and of religion to you, who have always 
 proved the strongest support of the Catholic Church. 
 
 * The square brackets, here and throughout the volume, are 
 used to mark additions to the original of the revised French 
 translation. 
 
PREFACE TO THE READER. 
 
 1 have already slightly touched upon the questions re- 
 specting the existence of God and the nature of the 
 human soul, in the "Discourse on the Method of 
 rightly conducting the Reason, and seeking truth in 
 the Sciences," published in French in the year 1637; 
 not, however, with the design of there treating of 
 them fully, but only, as it were, in passing, that I 
 might learn from the judgments of my readers in 
 what way I should afterwards handle them : for these 
 questions appeared to me to be of such moment as to 
 be worthy of being considered more than once, and 
 the path which I follow in discussing them is so little 
 trodden, and so remote from the ordinary route, that 
 I thought it would not be expedient to illustrate it at 
 greater length in French, and in a discourse that might 
 be read by all, lest even the more feeble minds should 
 believe that this path might be entered upon by them. 
 
 But, as in the Discourse on Method, I had requested 
 all who might find aught meriting censure in my writ- 
 ings, to do me the favour of pointing it out to me, I 
 may state that no objections worthy of remark have 
 been alleged against what I then said on these ques- 
 tions, except two, to which I will here briefly reply, 
 before undertaking their more detailed discussion. 
 
 The first objection is that though, while the hu- 
 9 
 
io PREFACE TO THE READER. 
 
 man mind reflects on itself, it does not perceive 1 * that 
 it is any other than a thinking thing, it does not follow 
 that its nature or essence consists only in its being 
 a thing which thinks ; so that the word only shall ex- 
 clude all other things which might also perhaps be 
 said to pertain to the nature of the mind. 
 
 To this objection I reply, that it was not my inten- 
 tion in that place to exclude these according to the 
 order of truth in the matter (of which I did not then 
 treat), but only according to the order of thought 
 (perception) ; so that my meaning was, that I clearly 
 apprehended nothing, so far as I was conscious, as be- 
 longing to my essence, except that I was a thinking 
 thing, or a thing possessing in itself the faculty of 
 thinking. But I will show hereafter how, from the 
 consciousness that nothing besides thinking belongs to 
 the essence of the mind, it follows that nothing else 
 does in truth belong to it. 
 
 The second objection is that it does not follow, from 
 my possessing the idea of a thing more perfect than I 
 am, that the idea itself is more perfect than myself, 
 and much less that what is represented by the idea 
 exists. 
 
 But I reply that in the term idea 2 there is here some- 
 thing equivocal ; for it may be taken either materially 
 for an act of the understanding, and in this sense it 
 cannot be said to be more perfect than I, or objec- 
 tively, for the thing represented by that act, which, 
 although it be not supposed to exist out of my under- 
 standing, may, nevertheless, be more perfect than my- 
 
 *The superior numerals in the text refer to the Notes at the 
 end of this volume, where will be found some notices of the 
 various terms that appeared to require comment. 
 
PREFACE TO THE READER. n 
 
 self, by reason of its essence. But, in the sequel of 
 this treatise I will show more amply how, from my 
 possessing the idea of a thing more perfect than my- 
 self, it follows that this thing really exists. 
 
 Besides these two objections, I have seen, indeed, 
 two treatises of sufficient length relating to the present 
 matter. In these, however, my conclusions, much 
 more than my premises, were impugned, and that by 
 arguments borrowed from the commonplaces of the 
 atheists. But, as arguments of this sort can make no 
 impression on the minds of those who shall rightly 
 understand my reasonings, and as the judgments of 
 many are so irrational and weak that they are per- 
 suaded rather by the opinions on a subject that are 
 first presented to them, however false and opposed to 
 reason they may be, than by a true and solid, but sub- 
 sequently received, refutation of them, I am unwilling 
 here to reply to these strictures from a dread of being, 
 in the first instance, obliged to state them. 
 
 I will only say, in general, that all which the athe- 
 ists commonly allege in favour of the non-existence of 
 God, arises continually from one or other of these two 
 things, namely, either the ascription of human affec- 
 tions to Deity, or the undue attribution to our minds 
 of so much vigour and wisdom that we may essay to 
 determine and comprehend both what God can and 
 ought to do ; hence all that is alleged by them will oc- 
 casion us no difficulty, provided only we keep in re- 
 membrance that our minds must be considered finite, 
 while Deity is incomprehensible and infinite. 
 
 Now that I have once, in some measure, made proof 
 of the opinions of men regarding my work, I again 
 undertake to treat of God and the human soul, and at 
 
12 PREFACE TO THE READER. 
 
 the same time to discuss the principles of the entire 
 First Philosophy, without, however, expecting any 
 commendation from the crowd for my endeavours, or 
 a wide circle of readers. On the contrary, I would 
 advise none to read this work, unless such as are able 
 and willing to meditate with me in earnest, to detach 
 their minds from commerce with the senses, and like- 
 wise to deliver themselves from all prejudice ; and in- 
 dividuals of this character are, I well know, remark- 
 ably rare. But with regard to those who, without 
 caring to comprehend the order and connection of the 
 reasonings, shall study only detached clauses for the 
 purpose of small but noisy criticism, as is the custom 
 with many, I may say that such persons will not profit 
 greatly by the reading of this treatise ; and although 
 perhaps they may find opportunity for cavilling in 
 several places, they will yet hardly start any pressing 
 objections, or such as shall be deserving of reply. 
 
 But since, indeed, I do not promise to satisfy others 
 on all these subjects at first sight, nor arrogate so 
 much to myself as to believe that I have been able to 
 foresee all that may be the source of difficulty to each 
 one, I shall expound, first of all, in the Meditations, 
 those considerations by which I feel persuaded that I 
 have arrived at a certain and evident knowledge of 
 truth, in order that I may ascertain whether the rea- 
 sonings which have prevailed with myself will also be 
 effectual in convincing others. I will then reply to the 
 objections of some men, illustrious for their genius and 
 learning, to whom these Meditations were sent for 
 criticism before they were committed to the press ; for 
 these objections are so numerous and varied that I 
 
PREFACE TO THE READER. 13 
 
 venture to anticipate that nothing, at least nothing of 
 any moment, will readily occur to any mind which has 
 not been touched upon in them. 
 
 Hence it is that I earnestly entreat my readers not 
 to come to any judgment on the questions raised in 
 the Meditations until they have taken care to read the 
 whole of the Objections, with the relative Replies. 
 
SYNOPSIS OF THE SIX FOLLOWING 
 MEDITATIONS. 
 
 In the First Meditation I expound the grounds on 
 which we may doubt in general of all things, and es- 
 pecially of material objects, so long, at least, as we 
 have no other foundations for the sciences than those 
 we have hitherto possessed. Now, although the util- 
 ity of a doubt so general may not be manifest at first 
 sight, it is nevertheless of the greatest, since it delivers 
 us from all prejudice, and affords the easiest pathway 
 by which the mind may withdraw itself from the 
 senses; and, finally, makes it impossible for us to 
 doubt wherever we afterwards discover truth. 
 
 In the Second, the mind which, in the exercise of 
 the freedom peculiar to itself, supposes that no object 
 is, of the existence of which it has even the slightest 
 doubt, finds that, meanwhile, it must itself exist. And 
 this point is likewise of the highest moment, for the 
 mind is thus enabled easily to distinguish what per- 
 tains to itself, that is, to the intellectual nature, from 
 what is to be referred to the body. But since some, 
 perhaps, will expect, at this stage of our progress,, a 
 statement of the reasons which establish the doctrine 
 of the immortality of the soul, I think it proper here 
 to make such aware, that it was my aim to write noth- 
 ing of which I could not give exact demonstration, and 
 that I therefore felt myself obliged to adopt an order 
 similar to that in use among the geometers, viz., to 
 15 
 
ï6 SYNOPSIS OF THE 
 
 premise all upon which the proposition in question de- 
 pends, before coming to any conclusion respecting it. 
 Now, the first and chief pre-requisite for the knowl- 
 edge of the immortality of the soul is our being able 
 to form the clearest possible conception (conceptus — 
 concept) of the soul itself, and such as shall be abso- 
 lutely distinct from all our notions of body; and how 
 this is to be accomplished is there shown. There is 
 required, besides this, the assurance that all objects 
 which we clearly and distinctly think are true (really 
 exist) in that very mode in which we think them ; and 
 this could not be established previously to the Fourth 
 Meditation. Farther, it is necessary, for the same 
 purpose, that we possess a distinct conception of cor- 
 poreal nature, which is given partly in the Second and 
 partly in the Fifth and Sixth Meditations. And, 
 finally, on these grounds, we are necessitated to con- 
 clude, that all those objects which are clearly and dis- 
 tinctly conceived to be diverse substances, as mind and 
 body, are substances really reciprocally distinct; and 
 this inference is made in the Sixth Meditation. The 
 absolute distinction of mind and body is, besides, con- 
 firmed in this Second Meditation, by showing that we 
 cannot conceive body unless as divisible ; while, on the 
 other hand, mind cannot be conceived unless as indi- 
 visible. For we are not able to conceive the half of 
 a mind, as we can of any body, however small, so that 
 the natures of these two substances are to be held, not 
 only as diverse, but even in some measure as contra- 
 ries. I have not; however, pursued this discussion 
 further in the present treatise, as well for the reason 
 that these considerations are sufficient to show that the 
 destruction of the mind does not follow from the cor- 
 
SIX FOLLOWING MEDITATIONS. 17 
 
 ruption of the body, and thus to afford to men the hope 
 of a future life, as also because the premises from 
 which it is competent for us to infer the immortality 
 of the soul, involve an explication of the whole prin- 
 ciples of Physics : in order to establish, in the first 
 place, that generally all substances, that is, all things 
 which can exist only in consequence of having been 
 created by God, are in their own nature incorruptible, 
 and can never cease to be, unless God himself, by re- 
 fusing his concurrence to them, reduce them to noth- 
 ing; and, in the second place, that body, taken gen- 
 erally, is a substance, and therefore can never perish, 
 but that the human body, in as far as it differs from 
 other bodies, is constituted only by a certain configura- 
 tion of members, and by other accidents of this sort, 
 while the human mind is not made up of accidents, but 
 is a pure substance. For although all the accidents of 
 the mind be changed — although, for example, it think 
 certain things, will others, and perceive others, the 
 mind itself does not vary with these changes ; while, on 
 the contrary, the human body is no longer the same if 
 a change take place in the form of any of its parts : 
 from which it follows that the body may, indeed, with- 
 out difficulty perish, but that the mind is in its own 
 nature immortal. 
 
 In the Third Meditation, I have unfolded at suffi- 
 cient length, as appears to me, my chief argument for 
 the existence of God. But yet, since I was there de- 
 sirous to avoid the use of comparisons taken from ma- 
 terial objects, that I might withdraw, as far as possi- 
 ble, the minds of my readers from the senses, numer- 
 ous obscurities perhaps remain, which, however, will, 
 I trust, be afterwards entirely removed in the Replies 
 
i8 SYNOPSIS OF THE 
 
 to the Objections: thus, among other things, it may 
 be difficult to understand how the idea of a being abso- 
 lutely perfect, which is found in our minds, possesses 
 so much objective reality 3 [i. e., participates by repre- 
 sentation in so many degrees of being and perfection] 
 that it must be held to arise from a cause absolutely 
 perfect. This is illustrated in the Replies by the com- 
 parison of a highly perfect machine, the idea of which 
 exists in the mind of some workman; for as the objec- 
 tive (i. e., representative) perfection of this idea must 
 have some cause, viz., either the science of the work- 
 man, or of some other person from whom he has re- 
 ceived the idea, in the same way the idea of God, 
 which is found in us, demands God himself for its 
 cause. 
 
 In the Fourth, it is shown that all which we clearly 
 and distinctly perceive (apprehend) is true; and, at 
 the same time, is explained wherein consists the na- 
 ture of error; points that require to be known as well 
 for confirming the preceding truths, as for the better 
 understanding of those that are to follow. But, mean- 
 while, it must be observed, that I do not at all there 
 treat of Sin, that is, of error committed in the pursuit 
 of good and evil, but of that sort alone which arises in 
 the determination of the true and the false. Nor do I 
 refer to matters of faith, or to the conduct of life, but 
 only to what regards speculative truths, and such as 
 are known by means of the natural light alone. 
 
 In the Fifth, besides the illustration of corporeal na- 
 ture, taken generically, a new demonstration is given 
 of the existence of God, not free, perhaps, any more 
 than the former, from certain difficulties, but of these 
 the solution will be found in the Replies to the Objec- 
 
SIX FOLLOWING MEDITATIONS. 19 
 
 tions. I further show, in what sense it is true that the. 
 certitude of geometrical demonstrations themselves is 
 dependent on the knowledge of God. 
 
 Finally, in the Sixth, the act of the understanding 
 (intellectio) is distinguished from that of the imagin- 
 ation (imaginatio) ; the marks of this distinction are 
 described ; the human mind is shown to be really dis- 
 tinct from the body, and, nevertheless, to be so closely 
 conjoined therewith, as together to form, as it were, a 
 unity. The whole of the errors which arise from the 
 senses are brought under review, while the means of 
 avoiding them are pointed out ; and, finally, all the 
 grounds are adduced from which the existence of ma- 
 terial objects may be inferred; not, however, because 
 I deemed them of great utility in establishing what 
 they prove, viz., that there is in reality a world, that 
 men are possessed of bodies, and the like, the truth of 
 which no one of sound mind ever seriously doubted; 
 but because, from a close consideration of them, it is 
 perceived that they are neither so strong nor clear as 
 the reasonings which conduct us to the knowledge of 
 our mind and of God ; so that the latter are, of all 
 which come under human knowledge, the most certain 
 and manifest — a conclusion which it was my single 
 aim in these Meditations to establish; on which" ac- 
 count I here omit mention of the various other ques- 
 tions which, in the course of the discussion, I had oc- 
 casion likewise to consider. 
 
MEDITATIONS ON THE FIRST 
 PHILOSOPHY, 
 
 IN WHICH 
 
 THE EXISTENCE OF GOD, AND THE REAL DISTINCTION OF 
 
 MIND AND BODY, ARE DEMONSTRATED. 
 
 MEDITATION I. 
 
 OF THE THINGS OF WHICH WE MAY DOUBT. 
 
 Several years have now elapsed since I first became 
 aware that I had accepted, even from my youth, many 
 false opinions for true, and that consequently what I 
 afterwards based on such principles was highly doubt- 
 ful ; and from that time I was convinced of the neces- 
 sity of undertaking once in my life to rid myself of all 
 the opinions I had adopted, and of commencing anew 
 the work of building from the foundation, if I desired 
 to establish a firm and abiding superstructure in the 
 sciences. But as this enterprise appeared to me to be 
 one of great magnitude, I waited until I had attained 
 an age so mature as to leave me no hope that at any 
 stage of life more advanced I should be better able to 
 execute my design. On this account, I have delayed 
 so long that I should henceforth consider I was doing 
 wrong were I still to consume in deliberation any of 
 the time that now remains for action. To-day, then, 
 
22 MEDITATION I. 
 
 since I have opportunely freed my mind from all 
 cares, [and am happily disturbed by no passions], and 
 since I am in the secure possession of leisure in a 
 peaceable retirement, I will at length apply myself 
 earnestly and freely to the general overthrow of all my 
 former opinions. But, to this end, it will not be neces- 
 sary for me to show that the whole of these are false 
 — a point, perhaps, which I shall never reach; but as 
 even now my reason convinces me that I ought not the 
 less carefully to withhold belief from what is not en- 
 tirely certain and indubitable, than from what is mani- 
 festly false, it will be sufficient to justify the rejection 
 of the whole if I shall find in each some ground for 
 doubt. Nor for this purpose will it be necessary even 
 to deal with each belief individually, which would be 
 truly an endless labour ; but, as the removal from be- 
 low of the foundation necessarily involves the down- 
 fall of the whole edifice, I will at once approach the 
 criticism of the principles on which all my former be- 
 liefs rested. 
 
 All that I have, up to this moment, accepted as pos- 
 sessed of the highest truth and certainty, I received 
 either from or through the senses. 4 I observed, how- 
 ever, that these sometimes misled us ; and it is the part 
 of prudence not to place absolute confidence in that by 
 which we have even once been deceived. 
 
 But it may be said, perhaps, that, although the 
 senses occasionally mislead us respecting minute ob- 
 jects, and such as are so far removed from us as to be 
 beyond the reach of close observation, there are yet 
 many other of their informations (presentations), of 
 the truth of which it is manifestly impossible to doubt ; 
 as for example, that I am in this place, seated by the 
 
OF THE THINGS OF WHICH WE MAY DOUBT. 23 
 
 fire, clothed in a winter dressing-gown, that I hold in 
 my hands this piece of paper, with other intimations 
 of the same nature. But how could I deny that I pos- 
 sess these hands and this body, and withal escape be- 
 ing classed with persons in a state of insanity, whose 
 brains are so disordered and clouded by dark bilious 
 vapours as to cause them pertinaciously to assert that 
 they are monarchs when they are in the greatest pov- 
 erty; or clothed [in gold J and purple when destitute 
 of any covering; or that their head is made of clay, 
 their body of glass, or that they are gourds ? I should 
 certainly be not less insane than they, were I to regu- 
 late my procedure according to examples so extrava- 
 gant. 
 
 Though this be true, I must nevertheless here con- 
 sider that I am a man, and that, consequently, I am in 
 the habit of sleeping, and representing to myself in 
 dreams those same things, or even sometimes others 
 less probable, which the insane think are presented to 
 them in their waking moments. How often have I 
 dreamt that I was in these familiar circumstances, — 
 that I was dressed, and occupied this place by the fire, 
 when I was lying undressed in bed? At the present 
 moment, however, I certainly look upon this paper 
 with eyes wide awake; the head which I now move is 
 not asleep; I extend this hand consciously and with 
 express purpose, and I perceive it; the occurrences in 
 sleep are not so distinct as all this. But I cannot for- 
 get that, at other times, I have been deceived in sleep 
 by similar illusions ; and, attentively considering those 
 cases, I perceive so clearly that there exist no certain 
 marks by which the state of waking can ever be dis- 
 
24 MEDITATION I. 
 
 tinguished from sleep, that I feel greatly astonished; 
 and in amazement I almost persuade myself that I am 
 now dreaming. 
 
 Let us suppose, then, that we are dreaming, and that 
 all these particulars — namely, the opening of the eyes, 
 the motion of the head, the forth-putting of the hands 
 — are merely illusions ; and even that we really possess 
 neither an entire body nor hands such as we see. 
 Nevertheless, it must be admitted at least that the ob- 
 jects which appear to us in sleep are, as it were, 
 painted representations which could not have been 
 formed unless in the likeness of realities; and, there- 
 fore, that those general objects, at all events, — namely, 
 eyes, a head, hands, and an entire body — are not sim- 
 ply imaginary, but really existent. For, in truth, 
 painters themselves, even when they study to represent 
 sirens and satyrs by forms the most fantastic and ex- 
 traordinary, cannot bestow upon them natures abso- 
 lutely new, but can only make a certain medley of the 
 members of different animals ; or if they chance to 
 imagine something so novel that nothing at" all similar 
 has ever been seen before, and such as is, therefore, 
 purely fictitious and absolutely false, it is at least cer- 
 tain that the colours of which this is composed are 
 real. 
 
 And on the same principle, although these general 
 objects, viz. [a body], eyes, a head, hands, and the 
 like, be imaginary, we are nevertheless absolutely 
 necessitated to admit the reality at least of some other 
 objects still more simple and universal than these, of 
 which, just as of certain real colours, all those images 
 
OF THE THINGS OF WHICH WE MAY DOUBT, 25 #**** 
 
 of things, whether true and real, or false and fantas-.. ' fji/c^f^"^ 
 tic, that are found in our consciousness (cogitatio) 5 ^'^^^ 
 are formed. ftta^Wr) ^ 
 
 To this class of objects seem to belong corporeal na- 
 ture in general and its extension ; the figure of ex- 
 tended things, their quantity or magnitude, and their 
 number, as also the place in, and the time during, 
 which they exist, and other things of the same sort. 
 We will not, therefore, perhaps reason illegitimately 
 if we conclude from this that Physics, Astronomy, 
 Medicine, and all the other sciences that have for their 
 end the consideration of composite objects, are indeed 
 of a doubtful character; but that Arithmetic, Geome- 
 try, and the other sciences of the same class, which re- 
 gard merely the simplest and most general objects, 
 and scarcely inquire whether or not these are really 
 existent, contain somewhat that is certain and indubit- 
 able : for whether I am awake or dreaming, it remains 
 true that two and three make five, and that a square 
 has but four sides; nor does it seem possible that 
 truths so apparent can ever fall under a suspicion of 
 falsity [or incertitude]. 
 
 Nevertheless, the belief that there is a God who is 
 all-powerful, and who created me, such as I am, has, 
 for a long time, obtained steady possession of my 
 mind. How, then, do I know that he has not ar- 
 ranged that there should be neither earth, nor sky, nor 
 any extended thing, nor figure, nor magnitude, nor 
 place, providing at the same time, however, for [the 
 rise in me of the perceptions of all these objects, and] 
 the persuasion that these do not exist otherwise than 
 as I perceive them? And further, as I sometimes 
 think that others are in error respecting matters of 
 
26 MEDITATION I. 
 
 which they believe themselves to possess a perfect 
 knowledge, how do I know that I am not also deceived 
 each time I add together two and three, or number the 
 sides of a square, or form some judgment still more 
 simple, if more simple indeed can be imagined? But 
 perhaps Deity has not been willing that I should be 
 thus deceived, for He is said to be supremely good. 
 If, however, it were repugnant to the goodness of 
 Deity to have created me subject to constant decep- 
 tion, it would seem likewise to be contrary to his good- 
 ness to allow me to be occasionally deceived ; and yet 
 it is clear that this is permitted. Some, indeed, might 
 perhaps be found who would be disposed rather to 
 deny the existence of a Being so powerful than to be- 
 lieve that there is nothing certain. But let us for the 
 present refrain from opposing this opinion, and grant 
 that all which is here said of a Deity is fabulous: 
 nevertheless in whatever way it be supposed that I 
 reached the state in which I exist, whether by fate, or 
 chance, or by an endless series of antecedents and con- 
 sequents, or by any other means, it is clear (since to 
 be deceived and to err is a certain defect) that the 
 probability of my being so imperfect as to be the con- 
 stant victim of deception, will be increased exactly in 
 proportion as the power possessed by the cause, to 
 which they assign my origin, is lessened. To these 
 reasonings I have assuredly nothing to reply, but am 
 constrained at last to avow that there is nothing of all 
 that I formerly believed to be true of which it is im- 
 possible to doubt, and that not through thoughtless- 
 ness or levity, but from cogent and maturely consid- 
 ered reasons ; so that henceforward, if I desire to dis- 
 cover anything certain, I ought not the less carefully 
 
OF THE THINGS OF WHICH WE MAY DOUBT. 27 
 
 to refrain from assenting to those same opinions than 
 to what might be shown to be manifestly false. 
 
 But it is not sufficient to have made these observa- 
 tions ; care must be taken likewise, to keep them in re- 
 membrance. For those old and customary opinions 
 perpetually recur — long and familiar usage giving 
 them the right of occupying my mind, even almost 
 against my will, and subduing my belief; nor will I 
 lose the habit of deferring to them and confiding in 
 them so long as I shall consider them to be what in 
 truth they are, viz., opinions to some extent doubtful, 
 as I have already shown, but still highly probable, and 
 such as it is much more reasonable to believe than 
 deny. It is for this reason I am persuaded that I shall 
 not be doing wrong, if, taking an opposite judgment 
 of deliberate design, I become my own deceiver, by 
 supposing, for a time, that all those opinions are en- 
 tirely false and imaginary, until at length, having thus 
 balanced my old by my new prejudices, my judgment 
 shall no longer be turned aside by perverted usage 
 from the path that may conduct to the perception of 
 truth. For I am assured that, meanwhile, there will 
 arise neither peril nor error from this course, and that 
 I cannot for the present yield too much to distrust, 
 since the end I now seek is not action but knowledge. 
 
 I will suppose, then, not that Deity, who is sover- 
 eignly good and the fountain of truth, but that some 
 malignant demon, who is at once exceedingly potent 
 and deceitful, has employed all his artifice to deceive 
 me; I will suppose that the sky, the air, the earth, 
 colours, figures, sounds, and all external things, are 
 nothing better than the illusions of dreams, by means 
 of which this being has laid snares for my credulity; 
 
28 MEDITATION I. 
 
 I will consider myself as without hands, eyes, flesh, 
 blood, or any of the senses, and as falsely believing 
 that I am possessed of these ; I will continue resolutely 
 fixed in this belief, and if indeed by this means it be 
 not in my power to arrive at the knowledge of truth, 
 I shall at least do what is in my power, viz., [suspend 
 my judgment], and guard with settled purpose against 
 giving my assent to what, is false, and being imposed 
 upon by this deceiver, whatever be his power and 
 artifice. 
 
 But this undertaking is arduous, and a certain indo- 
 lence insensibly leads me back to my ordinary course 
 of life; and just as the captive, who, perchance, was 
 enjoying in his dreams an imaginary liberty, when he 
 begins to suspect that it is but a vision, dreads awak- 
 ening, and conspires with the agreeable illusions that 
 the deception may be prolonged ; so I, of my own ac- 
 cord, fall back into the train of my former beliefs, and 
 fear to arouse myself from my slumber, lest the time 
 of laborious wakefulness that would succeed this quiet 
 rest, in place of bringing any light of day, should 
 prove inadequate to dispel the darkness that will arise 
 from the difficulties that have now been raised. 
 
MEDITATION IL 
 
 OF THE NATURE OF THE HUMAN MIND; AND THAT IT 
 IS MORE EASILY KNOWN THAN THE BODY. 
 
 The Meditation of yesterday has filled my mind with 
 so many doubts, that it is no longer in my power to 
 forget them. Nor do I see, meanwhile, any principle 
 on which they can be resolved; and, just as if I had 
 fallen all of a sudden into very deep water, I am so 
 greatly disconcerted as to be unable either to plant my 
 feet firmly on the bottom or sustain myself by swim- 
 ming on the surface. I will, nevertheless, make an 
 effort, and try anew the same path on which I had en- 
 tered yesterday, that is, proceed by casting aside all 
 that admits of the slightest doubt, not less than if I 
 had discovered it to be absolutely false; and I will 
 continue always in this track until I shall find some- 
 thing that is certain, or at least, if I can do nothing 
 more, until I shall know with certainty that there is 
 nothing certain. Archimedes, that he might transport 
 the entire globe from the place it occupied to another, 
 demanded only a point that was firm and immoveable ; 
 so also, I shall be entitled to entertain the highest ex- 
 pectations, if I am fortunate enough to discover only 
 one thing that is certain and indubitable. 
 
 I suppose, accordingly, that all the things which I 
 
 see are false (fictitious) ; I believe that none of those 
 
 objects which my fallacious memory represents ever 
 
 existed ; I suppose that I possess no senses ; I believe 
 
 29 
 
30 MEDITATION II. 
 
 that body, figure, extension, motion, and place are 
 merely fictions of my mind. What is there, then, that 
 can be esteemed true? Perhaps this only, that there 
 is absolutely nothing certain. 
 
 But how do I know that there is not something dif- 
 ferent altogether from the objects I have now enum- 
 erated, of which it is impossible to entertain the slight- 
 est doubt? Is there not a God, or some being, by 
 whatever name I may designate him, who causes these 
 thoughts to arise in my mind ? But why suppose such 
 a being, for it may be I myself am capable of produc- 
 ing them? Am I, then, at least not something? But 
 I before denied that I possessed senses or a body; I 
 hesitate, however, for what follows from that ? Am I 
 so dependent on the body and the senses that without 
 these I cannot exist? But I had the persuasion that 
 there was absolutely nothing in the world, that there 
 was no sky and no earth, neither minds nor bodies ; 
 was I not, therefore, at the same time, persuaded that 
 I did not exist? Far from it; I assuredly existed, 
 since I was persuaded. But there is I know not what 
 being, who is possessed at once of the highest power 
 and the deepest cunning, who is constantly employing 
 all his ingenuity in deceiving me. Doubtless, then, I 
 exist, since I am deceived ; and, let him deceive me as 
 he may, he can never bring it about that I am nothing, 
 so long as I shall be conscious that I am something. 
 So that it must, in fine, be maintained, all things being 
 maturely and carefully considered, that this proposi- 
 tion (pronunciatum) I am, I exist, is necessarily true 
 each time it is expressed by me, or conceived in my 
 mind. 
 
 But I do not yet know with sufficient clearness what 
 
OF THE NATURE OF THE HUMAN MIND. 31 
 
 I am, though assured that I am ; and hence, in the next 
 place, I must take care, lest perchance I inconsider- 
 ately substitute some other object in room of what is 
 properly myself, and thus wander from truth, even in 
 that knowledge (cognition) which I hold to be of all 
 others the most certain and evident. For this reason, 
 I will now consider anew what I formerly believed 
 myself to be, before I entered on the present train of 
 thought; and of my previous opinion I will retrench 
 all that can in the least be invalidated by the grounds 
 of doubt I have adduced, in order that there may at 
 length remain nothing but what is certain and indubit- 
 able. What then did I formerly think I was? Un- 
 doubtedly I judged that I was a man. But what is a 
 man ? Shall I say a rational animal ? Assuredly not ; 
 for it would be necessary forthwith to inquire into 
 what is meant by animal, and what by rational, and 
 thus, from a single question, I should insensibly glide 
 into others, and these more difficult than the first ; nor 
 do I now possess enough of leisure to warrant me in 
 wasting my time amid subtleties of this sort. I prefer 
 here to attend to the thoughts that sprung up of them- 
 selves in my mind, and were inspired by my own na- 
 ture alone, when I applied myself to the consideration 
 of what I was. In the first place, then, I thought that 
 I possessed a countenance, hands, arms, and all the 
 fabric of members that appears in a corpse, and which 
 I called by the name of body. It further occurred to 
 me that I was nourished, that I walked, perceived, and 
 thought, and all those actions I referred to the soul; 
 but what the soul itself was I either did not stay to 
 consider, or, if I did, I imagined that it was something 
 extremely rare and subtile, like wind, or flame, or 
 
32 MEDITATION II. 
 
 ether, spread through my grosser parts. As regarded 
 the body, I did not even doubt of its nature, but 
 thought I distinctly knew it, and if I had wished to 
 describe it according to the notions I then entertained, 
 I should have explained myself in this manner: By 
 body I understand all that can be terminated by a cer- 
 tain figure ; that can be comprised in a certain place, 
 and so fill a certain space as therefrom to exclude 
 every other body; that can be perceived either by 
 touch, sight, hearing, taste, or smell; that can be moved 
 in different ways, not indeed of itself, but by some- 
 thing foreign to it by which it is touched [and from 
 which it receives the impression] ; for the power of 
 self-motion, as likewise that of perceiving and think- 
 ing, I held as by no means pertaining to the nature of 
 body; on the contrary, I was somewhat astonished to 
 find such faculties existing in some bodies. 
 
 But [as to myself, what can I now say that I am], 
 since I suppose there exists an extremely powerful, 
 and, if I may so speak, malignant being, whose whole 
 endeavours are directed towards deceiving me? Can 
 I affirm that I possess any one of all those attributes 
 of which I have lately spoken as belonging to the na- 
 ture of body? After attentively considering them in 
 my own mind, I find none of them that can properly 
 be said to belong to myself. To recount them were 
 idle and tedious. Let us pass, then, to the attributes 
 of the soul. The first mentioned were the powers of 
 nutrition and walking ; but, if it be true that I have no 
 body, it is true likewise that I am capable neither of 
 walking nor of being nourished. Perception is an- 
 other attribute of the soul; but perception too is im- 
 possible without the body : besides, I have frequently, 
 
OF THE NATURE OF THE HUMAN MIND. 33 
 
 during sleep, believed that I perceived objects which 
 I afterwards observed I did not in reality perceive. 
 Thinking is another attribute of the soul ; and here I 
 discover what properly belongs to myself. This alone 
 is inseparable from me. I am — I exist: this is cer- 
 tain; but how often? As often as I think; for per- 
 haps it would even happen, if I should wholly cease to 
 think, that I should at the same time altogether cease 
 to be. I now admit nothing that is not necessarily 
 true : I am therefore, precisely speaking, only a think- 
 ing thing, that is, a mind (mens sive animus*), under- 
 standing, or reason, — terms whose signification was 
 ■before unknown to me. I am, however, a real thing, 
 and really existent; but what thing? The answer 
 was, a thinking thing. The question now arises, am 
 I aught besides? I will stimulate my imagination 
 with a view to discover whether I am not still some- 
 thing more than a thinking being. Now it is plain I 
 am not the assemblage of members called the human 
 body; I am not a thin and penetrating air diffused 
 through all these members, or wind, or flame, or va- 
 pour, or breath, or any of all the things I can imagine ; 
 for I supposed that all these were not, and, without 
 changing the supposition, I find that I still feel assured 
 of my existence. 
 
 But it is true, perhaps, that those very things which 
 I suppose to be non-existent, because they are un- 
 known to me, are not in truth different from myself 
 whom I know. This is a point I cannot determine, 
 and do not now enter into any dispute regarding it. I 
 can only judge of things that are known to me : I am 
 conscious that I exist, and I who know that I exist in- 
 quire into what I am. It is, however, perfectly cer- 
 
34 MEDITATION II. 
 
 tain that the knowledge of my existence, thus pre- 
 cisely taken, is not dependent on things, the existence 
 of which is as yet unknown to me : and consequently 
 it is not dependent on any of the things I can feign in 
 imagination. Moreover, the phrase itself, I frame an 
 image (effingo), reminds me of my error; for I should 
 in truth frame one if I were to imagine myself to be 
 anything, since to imagine is nothing more than to 
 contemplate the figure or image of a corporeal thing; 
 but I already know that I exist, and that it is possible 
 at the same time that all those images, and in general 
 all that relates to the nature of body, are merely 
 dreams for chimeras] . From this I discover that it is 
 not more reasonable to say, I will excite my imagina- 
 tion that I may know more distinctly what I am, than 
 to express myself as follows : I am now awake, and 
 perceive something real ; but because my perception is 
 not sufficiently clear, I will of express purpose go to 
 sleep that my dreams may represent to me the object 
 of my perception with more truth and clearness. And, 
 therefore, I know that nothing of all that I can em- 
 brace in imagination belongs to the knowledge which 
 I have of myself, and that there is need to recall with 
 the utmost care the mind from this mode of thinking, 
 that it may be able to know its own nature with per- 
 fect distinctness. 
 
 But what, then, am I? A thinking thing, it has 
 been said. But what is a thinking thing? It is a 
 thing that doubts, understands, [conceives], affirms, 
 denies, wills, refuses, that imagines also, and per- 
 ceives. Assuredly it is not little, if all these proper- 
 ties belong to my nature. But why should they not 
 belong to it? Am I not that very being who now 
 
OF THE NATURE OF THE HUMAN MIND. 35 
 
 doubts of almost everything ; who, for all that, under- 
 stands and conceives certain things; who affirms one 
 alone as true, and denies the others; who desires to 
 know more of them, and does not wish to be deceived ; 
 who imagines many things, sometimes even despite 
 his will ; and is likewise percipient of many, as if 
 through the medium of the senses. Is there nothing 
 of all this as true as that I am, even although I should 
 be always dreaming, and although he who gave me 
 being employed all his ingenuity to deceive me? Is 
 there also any one of these attributes that can be prop- 
 erly distinguished from my thought, or that can be 
 said to be separate from myself? For it is of itself so 
 evident that it is I who doubt, I who understand, and 
 I who desire, that it is here unnecessary to add any- 
 thing by way of rendering it more clear. And I am 
 as certainly the same being who imagines ; for, al- 
 though it may be (as I before supposed) that nothing 
 I imagine is true, still the power of imagination does 
 not cease really to exist in me and to form part of my 
 thought. In fine, I am the same being who perceives, 
 that is, who apprehends certain objects as by the or- 
 gans of sense, since, in truth, I see light, hear a noise, 
 and feel heat. But it will be said that these presenta- 
 tions are false, and that I am dreaming. Let it be so. 
 At all events it is certain that I seem to see light, hear 
 a noise, and feel heat ; this cannot be false, and this is 
 what in me is properly called perceiving (sentire), 
 which is nothing else than thinking. From this I be- 
 gin to know what I am with somewhat greater clear- 
 ness and distinctness than heretofore. 
 
 But, nevertheless, it still seems to me, and I cannot 
 help believing, that corporeal things, whose images 
 
36 MEDITATION IL 
 
 are formed by thought, [which fall under the senses], 
 and are examined by the same, are known with much 
 greater distinctness than that I know not what part of 
 myself which is not imaginable ; although, in truth, it 
 may seem strange to say that I know and comprehend 
 with greater distinctness things whose existence ap- 
 pears to me doubtful, that are unknown, and do not 
 belong to me, than others of whose reality I am per- 
 suaded, that are known to me, and appertain to my 
 proper nature ; in a word, than myself. But I see 
 clearly what is the state of the case. My mind is apt 
 to wander, and will not yet submit to be restrained 
 within the limits of truth. Let us therefore leave the 
 mind to itself once more, and, according to it every 
 kind of liberty, [permit it to consider the objects that 
 appear to it from without] , in order thai having after- 
 wards withdrawn it from these gently and oppor- 
 tunely, [and fixed it on the consideration of its being 
 and the properties it finds in itself], it may then be the 
 more easily controlled. 
 
 Let us now accordingly consider the objects that are 
 commonly thought to be [the most easily, and like- 
 wise] the most distinctly known, viz., the bodies we 
 touch and see ; not, indeed, bodies in general, for these 
 general notions are usually somewhat more confused, 
 but one body in particular. Take, for example, this 
 piece of wax; it is quite fresh, having been but re- 
 cently taken from the bee-hive ; it has not yet lost the 
 sweetness of the honey it contained ; it still retains 
 somewhat of the odour of the flowers from which it 
 was gathered ; its colour, figure, size, are apparent (to 
 the sight) ; it is hard, cold, easily handled; and sounds 
 when struck upon with the finger. In fine, all that 
 
OF THE NATURE OF THE HUMAN MIND. 3; 
 
 contributes to make a body as distinctly known as pos- 
 sible, is found in the one before us. But, while I am 
 speaking, let it be placed near the fire — what remained 
 of the taste exhales, the smell evaporates, the colour 
 changes, its figure is destroyed, its size increases, it 
 becomes liquid, it grows hot, it can hardly be handled, 
 and, although struck upon, it emits no sound. Does 
 the same wax still remain after this change ? It must 
 be admitted that it does remain; no one doubts it, or 
 judges otherwise. What, then, was it I knew with so 
 much distinctness in the piece of wax? Assuredly, it 
 could be nothing of all that I observed by means of 
 the senses, since all the things that fell under taste, 
 smell, sight, touch, and hearing are changed, and yet 
 the same wax remains. It was perhaps what I now 
 think, viz., that this wax was neither the sweetness of 
 honey, the pleasant odour of flowers, the whiteness, 
 the figure, nor the sound, but only a body that a little 
 before appeared to me conspicuous under these forms, 
 and which is now perceived under others. But, to 
 speak precisely, what is it that I imagine when I think 
 of it in this way ? Let it be attentively considered, and, 
 retrenching all that does not belong to the wax, let us 
 see what remains. There certainly remains nothing, 
 except something extended, flexible, and movable. 
 But what is meant by flexible and movable? Is it 
 not that I imagine that the piece of wax, being round, 
 is capable of becoming square, or of passing from a 
 square into a triangular figure? Assuredly such is 
 not the case, because I conceive that it admits of an in- 
 finity of similar changes ; and I am, moreover, unable 
 to compass this infinity by imagination, and conse- 
 quently this conception which I have of the wax is not 
 
38 MEDITATION IL 
 
 the product of the faculty of imagination. But what 
 now is this extension? Is it not also unknown? for 
 it becomes greater when the wax is melted, greater 
 when it is boiled, and greater still when the heat in- 
 creases; and I should not conceive [clearly and] ac- 
 cording to truth, the wax as it is, if I did not suppose 
 that the piece we are considering admitted even of a 
 wider variety of extension than I ever imagined. I 
 must, therefore, admit that I cannot even comprehend 
 by imagination what the piece of wax is, and that it is 
 the mind alone {mens, Lat., entendement, F.) which 
 perceives it. I speak of one piece in particular ; for, as 
 tp wax in general, this is still more evident. But what 
 is the piece of wax that can be perceived only by the 
 [understanding or] mind? It is certainly the same 
 which I see, touch, imagine ; and, in fine, it is the same 
 which, from the beginning, I believed it to be. But 
 (and this it is of moment to observe) the perception 
 of it is neither an act of sight, of touch, nor of imag- 
 ination, and never was either of these, though it might 
 formerly seem so, but is simply an intuition (inspec- 
 tio) of the mind, which may be imperfect and con- 
 fused, as it formerly was, or very clear and distinct, as 
 it is at present, according as the attention is more or 
 less directed to the elements which it contains, and of 
 which it is composed. 
 
 But, meanwhile, I feel greatly astonished when I ob- 
 serve [the weakness of my mind, and] its proneness to 
 error. For although, without at all giving expression 
 to what I think, I consider all this in my own mind, 
 words yet occasionally impede my progress, and I am 
 almost led into error by the terms of ordinary lan- 
 guage. We say, for example, that we see the same 
 
OF THE NATURE OF THE HUMAN MIND. 39 
 
 wax when it is before us, and not that we judge it to 
 be the same from its retaining the same colour and 
 figure : whence I should forthwith be disposed to con- 
 clude that the wax is known by the act of sight, and 
 not by the intuition of the mind alone, were it not for 
 the analogous instance of human beings passing on in 
 the street below, as observed from a window. In this 
 case I do not fail to say that I see the men themselves, 
 just as I say that I see the wax ; and yet what do I see 
 from the window beyond hats and cloaks that might 
 cover artificial machines, whose motions might be de- 
 termined by springs? But I judge that there are hu- 
 man beings from these appearances, and thus I com- 
 prehend, by the faculty of judgment alone which is in 
 the mind, what I believed I saw with my eyes. 
 
 The man who makes it his aim to rise to knowledge 
 superior to the common, ought to be ashamed to seek 
 occasions of doubting from the vulgar forms of 
 speech : instead, therefore, of doing this, I shall pro- 
 ceed with the matter in hand, and inquire whether I 
 had a clearer and more perfect perception of the piece 
 of wax when I first saw it, and when I thought I knew 
 it by means of the external sense itself, or, at all 
 events, by the common sense (sensus communis), as it 
 is called, that is, by the imaginative faculty; or 
 whether I rather apprehend it more clearly at present, 
 after having examined with greater care, both what it 
 is, and in what way it can be known. It would cer- 
 tainly be ridiculous to entertain any doubt on this 
 point. For what, in that first perception, was there 
 distinct? What did I perceive which any animal 
 might not have perceived? But when I distinguish 
 the wax from its exterior forms, and when, as if I had 
 
40 MEDITATION II. 
 
 stripped it of its vestments, I consider it quite naked, 
 it is certain, although some error may still be found in 
 my judgment, that I cannot, nevertheless, thus appre- 
 hend it without possessing a human mind. 
 
 But, finally, what shall I say of the mind itself, that 
 is, of myself? for as yet I do not admit that I am any- 
 thing but mind. What, then ! I who seem to possess 
 so distinct an apprehension of the piece, of wax, — do I 
 not know myself, both with greater truth and certi- 
 tude, and also much more distinctly and clearly? For 
 if I judge that the wax exists because I see it, it as- 
 suredly follows, much more evidently, that I myself 
 am or exist, for the same reason : for it is possible that 
 what I see may not in truth be wax, and that I do not 
 even possess eyes with which to see anything; but it 
 cannot be that when I see, or, which comes to the same 
 thing, when I think I see, I myself who think am noth- 
 ing. So likewise, if I judge that the wax exists be- 
 cause I touch it, it will still also follow that I am ; and 
 if I determine that my imagination, or any other 
 cause, whatever it be, persuades me of the existence 
 of the wax, I will still draw the same conclusion. And 
 what is here remarked of the piece of wax, is appli- 
 cable to all the other things that are external to me. 
 And further, if the [notion or] perception of wax ap- 
 peared to me more precise and distinct, after that not 
 only sight and touch, but many other causes besides, 
 rendered it manifest to my apprehension, with how 
 much greater distinctness must I now know myself, 
 since all the reasons that contribute to the knowledge 
 of the nature of wax, or of any body whatever, mani- 
 fest still better the nature of my mind? And there 
 are besides so many other things in the mind itself 
 
OF THE NATURE OF THE HUMAN MIND. 41 
 
 that contribute to the illustration of its nature, that 
 those dependent on the body, to which I have here re- 
 ferred, scarcely merit to be taken into account. 
 
 But, in conclusion, I find I have insensibly reverted 
 to the point I desired ; for, since it is now manifest to 
 me that bodies themselves are not properly perceived 
 by the senses nor by the faculty of imagination, but by 
 the intellect alone ; and since they are not perceived 
 because they are seen and touched, but only because 
 they are understood [or rightly comprehended by 
 thought] , I readily discover that there is nothing more 
 easily or clearly apprehended than my own mind. But 
 because it is difficult to rid one's self so promptly of 
 an opinion to which one has been long accustomed, it 
 will be desirable to tarry for some time at this stage, 
 that, by long continued meditation, I may more deeply 
 impress upon my memory this new knowledge. 
 
MEDITATION III. 
 of god: that he exists. 
 
 I will now close my eyes, I will stop my ears, I will 
 turn away my senses from their objects, I will even 
 efface from my consciousness all the images of cor- 
 poreal things; or at least, because this can hardly be 
 accomplished, I will consider them as empty and false ; 
 and thus, holding converse only with myself, and 
 closely examining my nature, I will endeavour to ob- 
 tain by degrees a more intimate and familiar knowl- 
 edge of myself. I am a thinking (conscious) thing, 
 that is, a being who doubts, affirms, denies, knows a 
 few objects, and is ignorant of many, — [who loves, 
 hates], wills, refuses, — who imagines likewise, and 
 perceives ; for, as I before remarked, although the 
 things which I perceive or imagine are perhaps noth~ 
 ing at all apart from me [and in themselves], I am 
 nevertheless assured that those modes of conscious- 
 ness which I call perceptions and imaginations, in as 
 far only as they are modes of consciousness, exist in 
 me. A_nd in the little I have said I think I have sum- 
 med up all that I really know, or at least all that up 
 to this time I was aware I knew. Now, as I am en- 
 deavouring to extend my knowledge more widely, I 
 will use circumspection, and consider with care 
 whether I can still discover in myself anything fur- 
 ther which I have not yet hitherto observed. I am 
 certain that I am a thinking thing ; but do I not there- 
 42 
 
OF GOD: THAT HE EXISTS. 43 
 
 fore likewise know what is required to render me cer- 
 tain of a truth? In this first knowledge, doubtless, 
 there is nothing that gives me assurance of its truth ex- 
 cept the clear and distinct perception of what I affirm, 
 which would not indeed be sufficient to give me the as- 
 surance that what I say is true, if it could ever happen 
 that anything I thus clearly and distinctly perceived 
 should prove false ; and accordingly it seems to me 
 that I may now take as a general rule, that all that is 
 very clearly and distinctly apprehended (conceived) 
 is true. 
 
 Nevertheless I before received and admitted many 
 things as wholly certain and manifest, which yet I 
 afterwards found to be doubtful. What, then, were 
 those? They were the earth, the sky, the stars, and 
 all the other objects which I was in the habit of per- 
 ceiving by the senses. But what was it that I clearly 
 [and distinctly] perceived in them? Nothing more 
 than that the ideas and the thoughts of those objects 
 were presented to my mind. And even now I do not 
 deny that these ideas are found in my mind. But 
 there was yet another thing which I affirmed, and 
 which, from having been accustomed to believe it, I 
 thought I clearly perceived, although, in truth, I did 
 not perceive it at all ; I mean the existence of objects 
 external to me, from which those ideas proceeded, and 
 to which they had a perfect resemblance; and it was 
 here I was mistaken, or if I judged correctly, this as- 
 suredly was not to be traced to any knowledge I pos- 
 sessed (the force of my perception, Lat). 
 
 But when I considered any matter in arithmetic and 
 geometry, that was very simple and easy, as, for ex- 
 ample, that two and three added together make five, 
 
44 MEDITATION III. 
 
 and things of this sort, did I not view them with at 
 least sufficient clearness to warrant me in affirming 
 their truth? Indeed, if I afterwards judged that we 
 ought to doubt of these things, it was for no other rea- 
 son than because it occurred to me that a God might 
 perhaps have given me such a nature as that I should 
 be deceived, even respecting the matters that appeared 
 to me the most evidently true. But as often as this 
 preconceived opinion of the sovereign power of a God 
 presents itself to my mind, I am constrained to admit 
 that it is easy for him, if he wishes it, to cause me to 
 err, even in matters where I think I possess the high- 
 est evidence ; and, on the other hand, as often as I di- 
 rect my attention to things which I think I apprehend 
 with great clearness, I am so persuaded of their truth 
 that I naturally break out into expressions such as 
 these : Deceive me who may, no one will yet ever be 
 able to bring it about that I am not, so long as I shall 
 be conscious that I am, or at any future time cause it 
 to be true that I have never been, it being now true 
 that I am, or make two and three more or less than 
 five, in supposing which, and other like absurdities, I 
 discover a manifest contradiction. 
 
 And in truth, as I have no ground for believing that 
 Deity is deceitful, and as, indeed, I have not even con- 
 sidered the reasons by which the existence of a Deity 
 of any kind is established, the ground of doubt that 
 rests only on this supposition is very slight, and, so to 
 speak, metaphysical. But, that I may be able wholly 
 to remove it, I must inquire whether there is a God, as 
 soon as an opportunity of doing so shall present itself ; 
 and if I find that there is a God, I must examine like- 
 wise whether he can be a deceiver; for, without the 
 
OF GOD: THAT HE EXISTS. 45 
 
 knowledge of these two truths, I do not see that I can 
 ever be certain of anything. And that I may be en- 
 abled to examine this without interrupting the order 
 of meditation I have proposed to myself [which is, to 
 pass by degrees from the notions that I shall find first 
 in my mind to those I shall afterwards discover in it], 
 it is necessary at this stage to divide all my thoughts 
 into certain classes, and to consider in which of these 
 classes truth and error are, strictly speaking, to be 
 found. 
 
 Of my thoughts some are, as it were, images of 
 things, and to these alone properly belongs the name 
 idea; as when I think [represent to my mind] a man, 
 a chimera, the sky, an angel, or God. Others, again, 
 have certain other forms ; as when I will, fear, affirm, 
 or deny, I always, indeed, apprehend something as the 
 object of my thought, but I also embrace in thought 
 something more than the representation of the object; 
 and of this class of thoughts some are called volitions 
 or affections, and others judgments. 
 
 Now, with respect to ideas, if these are considered 
 only in themselves, and are not referred to any object 
 beyond them, they cannot, properly speaking, be false ; 
 for, whether I imagine a goat or a chimera, it is not 
 less true that I imagine the one than the other. Nor 
 need we fear that falsity may exist in the will or affec- 
 tions ; for, although I may desire objects that are 
 wrong, and even that never existed, it is still true that 
 I desire them. There thus only remain our judg- 
 ments, in which we must take diligent heed that we be 
 not deceived. But the chief and most ordinary error 
 that arises in them consists in judging that the ideas 
 which are in us are like or conformed to the things 
 
46 MEDITATION III. 
 
 that are external to us ; for assuredly, if we but con- 
 sidered the ideas themselves as certain modes of our 
 thought (consciousness), without referring them to 
 anything beyond, they would hardly afford any occa- 
 sion of error. 
 
 But, among these ideas, some appear to me to be in- 
 nate 6 , others adventitious, and others to be made by 
 myself (factitious) ; for, as I have the power of con- 
 ceiving what is called a thing, or a truth, or a thought, 
 it seems to me that I hold this power from no other 
 source than my own nature ; but if I now hear a noise, 
 if I see the sun, or if I feel heat, I have all along 
 judged that these sensations proceeded from certain 
 objects existing out of myself; and, in fine, it appears 
 to me that sirens, hippogryphs, and the like, are inven- 
 tions of my own mind. But I may even perhaps come 
 to be of opinion that all my ideas are of the class 
 which I call adventitious, or that they are all innate, or 
 that they are all factitious, for I have not yet clearly 
 discovered their true origin; and what I have here 
 principally to do is to consider, with reference to those 
 that appear to come from certain objects without me, 
 what grounds there are for thinking them like these 
 objects. 
 
 The first of these grounds is that it seems to me I 
 am so taught by nature ; and the second that I am con- 
 scious that those ideas are not dependent on my will, 
 and therefore not on myself, for they are frequently 
 presented to me against my will, — as at present, 
 whether I will or not, I feel heat ; and I am thus per- 
 suaded that this sensation or idea (sensum vel ideam) 
 of heat is produced in me by something different from 
 myself, viz., by the heat of the fire by which I sit. And 
 
OF GOD: THAT HE EXISTS. 
 
 47 
 
 it is very reasonable to suppose that this object im- 
 presses me with its own likeness rather than any other 
 thing. 
 
 But I must consider whether these reasons are suf- 
 ficiently strong and convincing. When I speak of be- 
 ing taught by nature in this matter, I understand by 
 the word nature only a certain spontaneous impetus 
 that impels me to believe in a resemblance between 
 ideas and their objects, and not a natural light that af- 
 fords a knowledge of its truth. But these two things 
 are widely different ; for what the natural light shows 
 to be true can be in no degree doubtful, as, for exam- 
 ple, that I am because I doubt, and other truths of the 
 like kind: inasmuch as I possess no other faculty 
 whereby to distinguish truth from error, which can 
 teach me the falsity of what the natural light declares 
 to be true, and which is equally trustworthy ; but with 
 respect to [seemingly] natural impulses, I have ob- 
 served, when the question related to the choice of right 
 or wrong in action, that they frequently led me to take 
 the worse part; nor do I see that I have any better 
 ground for following them in what relates to truth 
 and error. Then, with respect to the other reason, 
 which is that because these ideas do not depend on my 
 will, they must arise from objects existing without me, 
 I do not find it more convincing than the former ; for, 
 just as those natural impulses, of which I have lately 
 spoken, are found in me, notwithstanding that they are 
 not always in harmony with my will, so likewise it 
 may be that I possess some power not sufficiently 
 known to myself capable of producing ideas without 
 the aid of external objects, and, indeed, it has always 
 hitherto appeared to me that they are formed during 
 
48 MEDITATION III. 
 
 sleep, by some power of this nature, without the aid of 
 aught external. And, in fine, although I should grant 
 that they proceeded from those objects, it is not a 
 necessary consequence that they must be like them. 
 On the contrary, I have observed, in a number of in- 
 stances, that there was a great difference between the 
 object and its idea. Thus, for example, I find in my 
 mind two wholly diverse ideas of the sun; the one, 
 by which it appears to me extremely small, draws its 
 origin from the senses, and should be placed in the 
 class of adventitious ideas; the other, by which it 
 seems to be many times larger than the whole earth, 
 is taken up on astronomical grounds, that is, elicited 
 from certain notions born with me, or is framed by 
 myself in some other manner. These two ideas can- 
 not certainly both resemble the same sun; and reason 
 teaches me that the one which seems to have imme- 
 diately emanated from it is the most unlike. And 
 these things sufficiently prove that hitherto it has not 
 been from a certain and deliberate judgment, but only 
 from a sort of blind impulse, that I believed in the ex- 
 istence of certain things different from myself, which, 
 by the organs of sense, or by whatever other means it 
 might be, conveyed their ideas or images into my mind 
 [and impressed it with their likenesses]. 
 
 But there is still another way of inquiring whether, 
 of the objects whose ideas are in my mind, there are 
 any that exist out of me. If ideas are taken in so far 
 only as they are certain modes of consciousness, I do 
 not remark any difference or inequality among them, 
 and all seem, in the same manner, to proceed from 
 myself ; but, considering them as images, of which one 
 represents one thing and another a different, it is evi- 
 
OF GOD: THAT HE EXISTS. 49 
 
 dent that a great diversity obtains among them. For, 
 without doubt, those that represent substances are 
 something more, and contain in themselves, so to 
 speak, more objective reality [that is, participate by 
 representation in higher degrees of being or perfec- 
 tion], than those that represent only modes or acci- 
 dents ; and again, the idea by which I conceive a God 
 [sovereign], eternal, infinite, [immutable]-, all-know- 
 ing, all-powerful, and the creator of all things that are 
 out of himself, — this, I say, has certainly in it more 
 objective reality than those ideas by which finite sub- 
 stances are represented. 
 
 Now, it is manifest by the natural light that there 
 must at least be as much reality in the efficient and to- 
 tal cause as in its effect; for whence can the effect 
 draw its reality if not from its cause? and how could 
 the cause communicate to it this reality unless it pos- 
 sessed it in itself? And hence it follows, not only 
 that what is cannot be produced by what is not, but 
 likewise that the more perfect, — in other words, that 
 which contains in itself more reality, — cannot be the 
 effect of the less perfect: and this is not only evi- 
 dently true of those effects, whose reality is actual or 
 formal, but likewise of ideas, whose reality is only 
 considered as objective. Thus, for example, the stone 
 that is not yet in existence, not only cannot now com- 
 mence to be, unless it be produced by that which pos- 
 sesses in itself, formally or eminently 7 , all that enters 
 into its composition, [in other words, by that which 
 contains in itself the same properties that are in the 
 stone, or others superior to them] ; and heat can only 
 be produced in a subject that was before devoid of it, 
 by a cause that is of an order [degree or kind], at 
 
SO MEDITATION III. 
 
 least as perfect as heat; and so of the others. But 
 further, even the idea of the heat, or of the stone, can- 
 not exist in me unless it be put there by a cause that 
 contains, at least, as much reality as I conceive exist- 
 ent in the heat or in the stone : for, although that cause 
 may not transmit into my idea anything of its actual 
 or formal reality, we ought not on this account to im- 
 agine that it is less real ; but we ought to consider 
 that, [as every idea is a work of the mind], its nature 
 is such as of itself to demand no other formal reality 
 than that which it borrows from our consciousness, of 
 which it is but a mode, [that is, a manner or way of 
 thinking] . But in order that an idea may contain this 
 objective reality rather than that, it must doubtless de- 
 rive it from some cause in which is found at least 
 as much formal reality as the idea contains of objec- 
 tive; for, if we suppose that there is found in an idea 
 anything which was not in its cause, it must of course 
 derive this from nothing. But, however imperfect may 
 be the mode of existence by which a thing is objec- 
 tively [or by representation] in the understanding by 
 its idea, we certainly cannot, for all that, allege that 
 this mode of existence is nothing, nor, consequently, 
 that the idea owes its origin to nothing. Nor must it 
 be imagined that, since the reality which is considered 
 in these ideas is only objective, the same reality need 
 not be formally (actually) in the causes of these ideas, 
 but only objectively: for, just as the mode of existing 
 objectively belongs to ideas by their peculiar nature, 
 so likewise the mode of existing formally appertains 
 to the causes of these ideas (at least to the first and 
 principal), by their peculiar nature. And although 
 an idea may give rise to another idea, this regress can- 
 
OF GOD: THAT HE EXISTS. 51 
 
 not, nevertheless, be infinite ; we must in the end reach 
 a first idea, the cause of which is, as it were, the arche- 
 type in which all the reality [or perfection] that is 
 found objectively [or by representation] in these ideas 
 is contained formally [and in act] . I am thus clearly 
 taught by the 'natural light that ideas exist in me as 
 pictures or images, which may in truth readily fall 
 short of the perfection of the objects from which they 
 are taken, but can never contain anything greater or 
 more perfect. 
 
 And in proportion to the time and care with which 
 I examine all those matters, the conviction of their 
 truth brightens and becomes distinct. But, to sum 
 up, what conclusion shall I draw from it all? It is 
 this; — if the objective reality [or perfection] of any 
 one of my ideas be such as clearly to convince me, that 
 this same reality exists in me neither formally nor emi- 
 nently, and if, as follows from this, I myself cannot be 
 the cause of it, it is a necessary consequence that I am 
 not alone in the world, but that there is besides myself 
 some other being who exists as the cause of that idea ; 
 while, on the contrary, if no such idea be found in my 
 mind, I shall have no sufficient ground of assurance 
 of the existence of any other being besides myself ; for, 
 after a most careful search, I have, up to this moment, 
 been unable to discover any other ground. 
 
 But, among these my ideas, besides that which rep- 
 resents myself, respecting which there can be here no 
 difficulty, there is one that represents a God; others 
 that represent corporeal and inanimate things; others 
 angels ; others animals ; and, finally, there are some 
 that represent men like myself. But with respect to 
 the ideas that represent other men, or animals, or 
 
52 MEDITATION III. 
 
 angels, I can easily suppose that they were formed by 
 the mingling and composition of the other ideas which 
 I have of myself, of corporeal things, and of God, al- 
 though there were, apart from myself, neither men, 
 animals, nor angels. And with regard to the ideas of 
 corporeal objects, I never discovered in them anything 
 so great or excellent which I myself did not appear 
 capable of originating ; for, by considering these ideas 
 closely and scrutinising them individually, in the same 
 way that I yesterday examined the idea of wax, I find 
 that there is but little in them that is clearly and dis- 
 tinctly perceived. As belonging to the class of things 
 that are clearly apprehended, I recognise the follow- 
 ing, viz., magnitude or extension in length, breadth, 
 and depth; figure, which results from the termination 
 of extension ; situation, which bodies of diverse figures 
 preserve with reference to each other; and motion or 
 the change of situation; to which may be added sub- 
 stance, duration, and number. But with regard to 
 light, colours, sounds, odours, tastes, heat, cold, and 
 the other tactile qualities, they are thought with so 
 much obscurity and confusion, that I cannot determine 
 even whether they are true or false ; in other words, 
 whether or not the ideas I have of these qualities are 
 in truth the ideas of real objects. For although I be- 
 fore remarked that it is only in judgments that formal 
 falsity, or falsity properly so called, can be met with, 
 there may nevertheless be found in ideas a certain ma- 
 terial falsity, which arises when they represent what is 
 nothing as if it were something. Thus, for example, 
 the ideas I have of cold and heat are so far from being 
 clear and distinct, that I am unable from them to dis- 
 cover whether cold is only the privation of heat, or 
 
OF GOD: THAT HE EXISTS. 53 
 
 heat the privation of cold ; or whether they are not real 
 qualities : and since, ideas being as it were images, there 
 can be none that does not seem to us to represent 
 some object, the idea which represents cold as some- 
 thing real and positive will not improperly be called 
 false, if it be correct to say that cold is nothing but a 
 privation of heat; and so in other cases. To ideas of 
 this kind, indeed, it is not necessary that I should as- 
 sign any author besides myself: for if they are false, 
 that is, represent objects that are unreal, the natural 
 light teaches me that they proceed from nothing; in 
 other words, that they are in me only because some- 
 thing is wanting to the perfection of my nature ; but if 
 these ideas are true, yet because they exhibit to me so 
 little reality that I cannot even distinguish the object 
 represented from non-being, I do not see why I should 
 not be the author of them. 
 
 With reference to those ideas of corporeal things 
 that are clear and distinct, there are some which, as ap- 
 pears to me, might have been taken from the idea I 
 have of myself, as those of substance, duration, num- 
 ber, and the like. For when I think that a stone is a 
 substance, or a thing capable of existing of itself, and 
 that I am likewise a substance, although I conceive that 
 I am a thinking and non-extended thing, and that the 
 stone, on the contrary, is extended and unconscious, 
 there being thus the greatest diversity between the two 
 concepts, — yet these two ideas seem to have this in 
 common that they both represent substances. In the 
 same way, when I think of myself as now existing, and 
 recollect besides that I existed some time ago, and 
 when I am conscious of various thoughts whose num- 
 ber I know, I then acquire the ideas of duration and 
 
54 MEDITATION III. 
 
 number, which I can afterwards transfer to as many 
 objects as I please. With respect to the other quali- 
 ties that go to make up the ideas of corporeal objects, 
 viz., extension, figure, situation, and motion, it is true 
 that they are not formally in me, since I am merely a 
 thinking being ; but because they are only certain modes 
 of substance, and because I myself am a substance, it 
 seems possible that they may be contained in me emi- 
 nently. 
 
 There only remains, therefore, the idea of God, in 
 which I must consider whether there is anything that 
 cannot be supposed to originate with myself. By the 
 name God, I understand a substance infinite, [eternal, 
 immutable], independent, all-knowing, all-powerful, 
 and by which I myself, and every other thing that ex- 
 ists, if any such there be, were created. But these 
 properties are so great and excellent, that the more at- 
 tentively I consider them the less I feel persuaded that 
 the idea I have of them owes its origin to myself alone. 
 And thus it is absolutely necessary to conclude, from 
 all that I have before said, that God exists : for though 
 the idea of substance be in my mind owing to this, that 
 I myself am a substance, I should not, however, have 
 the idea of an infinite substance, seeing I am a finite 
 being, unless it were given me by some substance in 
 reality infinite. 
 
 And I must not imagine that I do not apprehend the 
 infinite by a true idea, but only by the negation of the 
 finite, in the same way that I comprehend repose and 
 darkness by the negation of motion and light: since, 
 on the contrary, I clearly perceive that there is more 
 reality in the infinite substance than in the finite, and 
 therefore that in some way I possess the perception 
 
OF GOD: THAT HE EXISTS. 55 
 
 (notion) of the infinite before that of the finite, that is, 
 the perception of God before that of myself, for how 
 could I know that I doubt, desire, or that something 
 is wanting to me, and that I am not wholly perfect, if 
 I possessed no idea of a being more perfect than my- 
 self, by comparison of which I knew the deficiencies of 
 my nature? 
 
 And it cannot be said that this idea of God is per- 
 haps materially false, and consequently that it may 
 have arisen from nothing, [in other words, that it may 
 exist in me from my imperfection], as I before said 
 of the ideas of heat and cold, and the like : for, on the 
 contrary, as this idea is very clear and distinct, and 
 contains in itself more objective reality than any other, 
 there can be no one of itself more true, or less open to 
 the suspicion of falsity. 
 
 The idea, I say, of a being supremely perfect, and 
 infinite, is in the highest degree true ; for although, per- 
 haps, we may imagine that such a being does not exist, 
 we cannot, nevertheless, suppose that his idea repre- 
 sents nothing real, as I have already said of the idea 
 of cold. It is likewise clear and distinct in the highest 
 degree, since whatever the mind clearly and distinctly 
 conceives as real or true, and as implying any perfec- 
 tion, is contained entire in this idea. And this is true, 
 nevertheless, although I do not comprehend the infinite, 
 and although there may be in God an infinity of things 
 that I cannot comprehend, nor perhaps even compass 
 by thought in any way ; for it is of the nature of the 
 infinite that it should not be comprehended by the 
 finite ; and it is enough that I rightly understand this, 
 and judge that all which I clearly perceive, and in 
 which I know there is some perfection, and perhaps 
 
56 MEDITATION III. 
 
 also an infinity of properties of which I am ignorant, 
 are formally or eminently in Gocl, in order that the idea 
 I have of him may become the most true, clear, and 
 distinct of all the ideas in my mind. 
 
 B'ut perhaps I am something more than I suppose 
 myself to be, and it may be that all those perfections 
 which I attribute to God, in some way exist potentially 
 in me, although they do not yet show themselves, and 
 are not reduced to act. Indeed, I am already con- 
 scious that my knowledge is being increased [and per- 
 fected] by degrees ; and I see nothing to prevent it 
 from thus gradually increasing to infinity, nor any 
 reason why, after such increase and perfection, I 
 should not be able thereby to acquire all the other per- 
 fections of the Divine nature ; nor, in fine, why the 
 power I possess of acquiring those perfections, if it 
 really now exist in me, should not be sufficient to pro- 
 duce the ideas of them. Yet, on looking more closely 
 into the matter, I discover that this cannot be ; for, in 
 the first place, although it were true that my knowledge 
 daily acquired new degrees of perfection, and although 
 there were potentially in my nature much that was not 
 as yet actually in it, still all these excellences make not 
 the slightest approach to the idea I have of the Deity, 
 in whom there is no perfection merely potentially [but 
 all actually] existent; for it is even an unmistakeable 
 token of imperfection in my knowledge, that it is aug- 
 mented by degrees. Further, although my knowledge 
 increase more and more, nevertheless I am not, there- 
 fore, induced to think that it will ever be actually infi- 
 nite, since it can never reach that point beyond which 
 it shall be incapable of further increase. But I con- 
 ceive God as actually infinite, so that nothing can be 
 
OF GOD: THAT HE EXISTS. 57 
 
 added to his perfection. And, in fine, I readily per- 
 ceive that the objective being of an idea cannot be pro- 
 duced by a being that is merely potentially existent, 
 which, properly speaking, is nothing, but only by a 
 being existing formally or actually. 
 
 And, truly, I see nothing in all that I have now said 
 which it is not easy for any one, who shall carefully 
 consider it, to discern by the natural light; but when 
 I allow my attention in some degree to relax, the vision 
 of my mind being obscured, and, as it were, blinded 
 by the images of sensible objects, I do not readily re- 
 member the reason why the idea ôf a being more per- 
 fect than myself, must of necessity have proceeded 
 from a being in reality more perfect. On this account 
 I am here desirous to inquire further, whether I, who 
 possess this idea of God, could exist supposing there 
 were no God. And I ask, from whom could I, in that 
 case, derive my existence? Perhaps from myself, or 
 from my parents, or from some other causes less per- 
 fect than God ; for anything more perfect, or even 
 equal to God, cannot be thought or imagined. But if 
 I [were independent of every other existence, and] 
 were myself the author of my being, I should doubt 
 of nothing, I should desire nothing, and, in fine, no per- 
 fection would be awanting to me; for I should have 
 bestowed upon myself every perfection of which I pos- 
 sess the idea, and I should thus be God. And it must 
 not be imagined that what is now wanting to me is per- 
 haps of more difficult acquisition than that of which I 
 am already possessed ; for, on the contrary, it is quite 
 manifest that it was a matter of much higher difficulty 
 that I, a thinking being, should arise from nothing, 
 than it would be for me to acquire the knowledge of 
 
58 MEDITATION III. 
 
 many things of which I am ignorant, and which are 
 merely the accidents of a thinking substance ; and cer- 
 tainly, if I possessed of myself the greater perfection 
 of which I have now spoken, [in other words, if I were 
 the author of my own existence], I would not at least 
 have denied to myself things that may be more easily 
 obtained, [as that infinite variety of knowledge of 
 which I am at present destitute] . I could not, indeed, 
 have denied to myself any property which I perceive 
 is contained in the idea of God, because there is none 
 of these that seems to me to be more difficult to make 
 or acquire ; and if there were any that should happen 
 to be more difficult to acquire, they would certainly ap- 
 pear so to me (supposing that I myself were the source 
 of the other things I possess), because I should dis- 
 cover in them a limit to my power. And though I 
 were to suppose that I always was as I now am, I 
 should not, on this ground, escape the force of these 
 reasonings, since it would not follow, even on this sup- 
 position, that no author of my existence needed to be 
 sought after. For the whole time of my life may be 
 divided into an infinity of parts, each of which is in no 
 way dependent on any other ; and, accordingly, because 
 I was in existence a short time ago, it does not follow 
 that I must now exist, unless in this moment some 
 cause create me anew as it were, — that is, conserve me. 
 In truth, it is perfectly clear and evident to all who 
 will attentively consider the nature of duration, that 
 the conservation of a substance, in each moment of its 
 duration, requires the same power and act that would 
 be necessary to create it, supposing it were not yet in 
 existence ; so that it is manifestly a dictate of the nat- 
 ural light that conservation and creation differ merely 
 
OF GOD: THAT HE EXISTS. 59 
 
 in respect of our mode of thinking [and not in reality]. 
 All that is here required, therefore, is that I interrogate 
 myself to discover whether I possess any power by 
 means of which I can bring it about that I, who now 
 am, shall exist a moment afterwards ; for, since I am 
 merely a thinking thing (or since, at least, the precise 
 question, in the meantime, is only of that part of my- 
 self), if such a power resided in me, I should, without 
 doubt, be conscious of it; but I am conscious of no 
 such power, and thereby I manifestly know that I am 
 dependent upon some being different from myself. 
 
 But perhaps the being upon whom I am dependent, 
 is not God, and I have been produced either by my 
 parents, or by some causes less perfect than Deity. 
 This cannot be : for, as I before said, it is perfectly evi- 
 dent that there must at least be as much reality in the 
 cause as in its effect; and accordingly, since I am a 
 thinking thing, and possess in myself an idea of God, 
 whatever in the end be the cause of my existence, it 
 must of necessity be admitted that it is likewise a 
 thinking being, and that it possesses in itself the idea 
 and all the perfections I attribute to Deity. Then it 
 may again be inquired whether this cause owes its 
 origin and existence to itself, or to some other cause. 
 For if it be self-existent, it follows, from what I have 
 before laid down, that this cause is God; for, since it 
 possesses the perfection of self -existence, it must like- 
 wise, without doubt, have the power of actually pos- 
 sessing every perfection of which it has the idea, — in 
 other words, all the perfections I conceive to belong to 
 God. But if it owe its existence to another cause than 
 itself, we demand again, for a similar reason, whether 
 this second cause exists of itself or through some other, 
 
6o MEDITATION III. 
 
 until, from stage to stage, we at length arrive at an ul- 
 timate cause, which will be God. And it is quite man- 
 ifest that in this matter there can be no infinite regress 
 of causes, seeing that the question raised respects not 
 so much the cause which once produced me, as that 
 by which I am. at this present moment conserved. 
 
 Nor can it be supposed that several causes concurred 
 in my production, and that from one I received the 
 idea of one of the perfections I attribute to Deity, and 
 from another the idea of some other, and thus that all 
 those perfections are indeed found somewhere in the 
 universe, but do not all exist together in a single being 
 who is God; for, on the contrary, the unity, the sim- 
 plicity or inseparability of all the properties of Deity, 
 is one of the chief perfections 1 conceive him to pos- 
 sess ; and the idea of this unity of all the perfections of 
 Deity could certainly not be put into my mind by any 
 cause from which I did not likewise receive the ideas 
 of all the other perfections ; for no power could enable 
 me to embrace them in an inseparable unity, without 
 at the same time giving me the knowledge of what they 
 were [and of their existence in a particular mode] : 
 
 Finally, with regard to my parents [from whom it 
 appears I sprung] , although all that I believed respect- 
 ing them be true, it does not, nevertheless, follow that 
 I am conserved by them, on even that I was produced 
 by them, in so far as I am a thinking being. All that, 
 at the most, they contributed to my origin was the giv- 
 ing of certain dispositions (modifications) to the mat- 
 ter in which I have" hitherto judged that I or my mind, 
 which is what alone I now consider to be myself, is en- 
 closed; and thus there can here be no difficulty with 
 respect to them, and it is absolutely necessary to con- 
 
OF GOD: THAT HE EXISTS. 61 
 
 elude from this alone that I am, and possess the idea 
 of a being absolutely perfect, that is, of God, that his 
 existence is most clearly demonstrated. 
 
 There remains only the inquiry as to the way in 
 which I received this idea from God ; for I have not 
 drawn it from the senses, nor is it even presented to 
 me unexpectedly, as is usual with the ideas of sensible 
 objects, when these are presented or appear to be pre- 
 sented to the external organs of the senses ; it is not 
 even a pure production or fiction of my mind, for it is 
 not in my power to take from or add to it ; and conse- 
 quently there but remains the alternative that it is in- 
 nate, in the same way as is the idea of myself. And, 
 in truth, it is not to be wondered at that God, at my 
 creation, implanted this idea in me, that it might serve, 
 as it were, for the mark of the workman impressed on 
 his work; and it is not also necessary that the mark 
 should be something different from the work itself; 
 but considering only that God is my creator, it is highly 
 probable that he in some way fashioned me after his 
 own image and likeness, and that I perceive this like- 
 ness, in which is contained the idea of God, by the same 
 faculty by which I apprehend myself, — in other words, 
 when I make myself the object of. reflection, I not only 
 find that I am an incomplete, fimperfect] and depend- 
 ent being, and one who unceasingly aspires after some- 
 thing better and greater than he is ; but, at the same 
 time, I am assured likewise that he upon whom I am 
 dependent possesses in himself all the goods after 
 which I aspire, [and the ideas of which I find in my 
 mind], and that not merely indefinitely and potentially, 
 but infinitely and actually, and that he is thus God. 
 And the whole force of the argument of which I have 
 
62 MEDITATION III. 
 
 here availed myself to establish the existence of God, 
 consists in this, that I perceive I could not possibly be 
 of such a nature as I am, and yet have in my mind the 
 idea of a God, if God did not in reality exist, — this 
 same God, I say, whose idea is in my mind — that is, a 
 being who possesses all those lofty perfections, of 
 which the mind may have some slight conception, with- 
 out, however, being able fully to comprehend them — 
 and who is wholly superior to all defect, [and has noth- 
 ing that marks imperfection] : whence it is sufficiently 
 manifest that he cannot be a deceiver, since it is a dic- 
 tate of the natural light that all fraud and deception 
 spring from some defect. 
 
 But before I examine this with more attention, and 
 pass on to the consideration of other truths that may 
 be evolved out of it, I think it proper to remain here 
 for some time in the contemplation of God himself — 
 that I may ponder at leisure his marvellous attributes 
 — and behold, admire, and adore the beauty of this 
 light so unspeakably great, as far, at least, as the 
 strength of my mind, which is to some degree dazzled 
 by the sight, will permit. For just as we learn by faith 
 that the supreme felicity of another life consists in the 
 contemplation of the Divine majesty alone, so even now 
 we learn from experience that a like meditation, though 
 incomparably less perfect, is the source of the highest 
 satisfaction of which we are susceptible in this life. 
 
MEDITATION IV. 
 
 OF TRUTH AND ERROR. 
 
 I have been habituated these bygone days to detach 
 my mind from the senses, and I have accurately ob- 
 served that there is exceedingly little which is known 
 with certainty respecting corporeal objects, — that we 
 know much more of the human mind, and still more of 
 God himself. I am thus able now without difficulty 
 to abstract my mind from the contemplation of [sensi- 
 ble of] imaginable objects, and apply it to those which, 
 as disengaged from all matter, are purely intelligible. 
 And certainly the idea I have of the human mind in 
 so far as it is a thinking thing, and not extended in 
 length, breadth, and depth, and participating in none 
 of the properties of body, is incomparably more dis- 
 tinct than the idea of any corporeal object ; and when 
 I consider that I doubt, in other words, that I am an 
 incomplete and dependent being, the idea of a complete 
 and independent being, that is to say of God, occurs 
 to my mind with so much clearness and distinctness, 
 — and from the fact alone that this idea is found in me, 
 or that I who possess it exist, the conclusions that God 
 exists, and that my own existence, each moment of its 
 continuance, is absolutely dependent upon him, are so 
 manifest, — as to lead me to believe it impossible that 
 the human mind can know anything with more clear- 
 ness and certitude. And now I seem to discover a 
 path that will conduct us from the contemplation of 
 63 
 
64 MEDITATION IV. 
 
 the true God, in whom are contained all the treasures 
 of science and wisdom, to the knowledge of the other 
 things in the universe. 
 
 For, in the first place, I discover that it is impossible 
 for him ever to deceive me, for in all fraud and deceit 
 there is a certain imperfection : and although it may 
 seem that the ability to deceive is a mark of subtlety 
 or power, yet the will testifies without doubt of malice 
 and weakness ; and such, accordingly, cannot be found 
 in God. In the next place, I am conscious that I pos- 
 sess a certain faculty of judging [or discerning truth 
 from error], which I doubtless received from God, 
 along with whatever else is mine ; and since it is im- 
 possible that he should will to deceive me, it is likewise 
 certain that he has not given me a faculty that will ever 
 lead me into error, provided I use it aright. 
 
 And there would remain no doubt on this head, did 
 it not seem to follow from this, that I can never there- 
 fore be deceived ; for if all I possess be from God, and 
 if he planted in me no faculty that is deceitful, it seems 
 to follow that I can never fall into error. Accord- 
 ingly, it is true that when I think only of God (when 
 I. look upon myself as coming from God, Fr.), and 
 turn wholly to him, I discover [in myself] no cause 
 of error or falsity : but immediately thereafter, recur- 
 ring to myself, experience assures me that I am never- 
 theless subject to innumerable errors. When I come 
 to inquire into the cause of these, I observe that there 
 is not only present to my consciousness a real and pos- 
 itive idea of God, or of a being supremely perfect, but 
 also, so to speak, a certain negative idea of nothing, — 
 in other words, of that which is at an infinite distance 
 from every sort of perfection, and that I am, as it were, 
 
OF TRUTH AND ERROR. 65 
 
 a mean between God and nothing, or placed in such a 
 way between absolute existence and non-existence, that 
 there is in truth nothing in me to lead me into error, 
 in so far as an absolute being is my creator ; but that, 
 on the other hand, as I thus likewise participate in some 
 degree of nothing or of non-being, in other words, as 
 I am not myself the supreme Being, and as I am want- 
 ing in many perfections, it is not surprising I should 
 fall into error. And I hence discern that error, so far 
 as error is not something real, which depends for its 
 existence on God, but is simply defect; and therefore 
 that, in order to fall into it, it is not necessary God 
 should have given me a faculty expressly for this end, 
 but that my being deceived arises from the circum- 
 stance that the power which God has given me of dis- 
 cerning truth from error is not infinite. 
 
 Nevertheless this is not yet quite satisfactory ; for er- 
 ror is not a pure negation, [in other words, it is not the 
 simple deficiency or want of some knowledge which is 
 not due] , but the privation or want of some knowledge 
 which it would seem I ought to possess. But, on con- 
 sidering the nature of God, it seems impossible that 
 he should have planted in his creature any faculty not 
 perfect in its kind, that is, wanting in some perfection 
 due to it : for if it be true, that in proportion to the 
 skill of the maker the perfection of his work is greater, 
 what thing can have been produced by the supreme 
 Creator of the universe that is not absolutely perfect 
 in all its parts ? And assuredly there is no doubt that 
 God could have created me such as that I should never 
 be deceived ; it is certain, likewise, that he always wills 
 what is best ; is it better, then, that I should be capa- 
 ble of being: deceived than that I should not ? 
 
66 MEDITATION IV. 
 
 Considering this more attentively, the first thing that 
 occurs to me is the reflection that I must not be sur- 
 prised if I am not always capable of comprehending 
 the reasons why God acts as he does ; nor must I doubt 
 of his existence because I find, perhaps, that there are 
 several other things besides the present respecting 
 which I understand neither why nor how they were 
 created by him; for, knowing already that my nature 
 is extremely weak and limited, and that the nature of 
 God, on the other hand, is immense, incomprehensible, 
 and infinite, I have no longer any difficulty in discern- 
 ing that there is an infinity of things in his power 
 whose causes transcend the grasp of my mind : and 
 this consideration alone is sufficient to convince me, 
 that the whole class of final causes is of no avail in 
 physical [or natural] things; for it appears to me that 
 I cannot, without exposing myself to the charge of 
 temerity, seek to discover the [impenetrable] ends of 
 Deity. 
 
 It further occurs to me that we must not consider 
 only one creature apart from the others, if we wish to 
 determine the perfection of the works of Deity, but 
 generally all his creatures together; for the same ob- 
 ject that might perhaps, with some show of reason, be 
 deemed highly imperfect if it were alone in the world, 
 may for all that be the most perfect possible, consid- 
 ered as forming part of the whole universe: and al- 
 though, as it was my purpose to doubt of everything, 
 I only as yet know with certainty my own existence 
 and that of God, nevertheless, after having remarked 
 the infinite power of Deity, I cannot deny that he may 
 have produced many other objects, or at least that he 
 is able to produce them, so that I may occupy a place 
 
OF TRUTH AND ERROR. 67 
 
 in the relation of a part to the great whole of his crea- 
 tures. 
 
 Whereupon, regarding myself more closely, and 
 considering what my errors are (which alone testify to 
 the existence of imperfection in me), I observe that 
 these depend on the concurrence of two causes, viz., 
 the faculty of cognition which I possess, and that of 
 election or the power of free choice, — in other words, 
 the understanding and the will. For by the under- 
 standing alone, I [neither affirm nor deny anything, 
 but] merely apprehend (percipio) the ideas regarding 
 which I may form a judgment; nor is any error, prop- 
 erly so called, found in it thus accurately taken. And 
 although there are perhaps innumerable objects in the 
 world of which I have no idea in my understanding, it 
 cannot, on that account, be said that I am deprived of 
 those ideas [as of something that is due to my nature], 
 but simply that I do not possess them, because, in 
 truth, there is no ground to prove that Deity ought to 
 have endowed me with a larger faculty of cognition 
 than he has actually bestowed upon me; and however 
 skilful a workman I suppose him to be, I have no rea- 
 son, on that account, to think that it was obligatory on 
 him to give to each of his works all the perfections 
 he is able to bestow upon some. Nor, moreover, can 
 I complain that God has not given me freedom of 
 choice, or a will sufficiently ample and perfect, since, 
 in truth, I am conscious of will so ample and extended 
 as to be superior to all limits. And what appears to 
 me here to be highly remarkable is that, of all the 
 other properties I possess, there is none so great and 
 perfect as that I do not clearly discern it could be still 
 greater and more perfect. For, to take an example, if 
 
68 MEDITATION IV. 
 
 I consider the faculty of understanding which I pos- 
 sess, I find that it is of very small extent, and greatly 
 limited, and at the same time I form the idea of an- 
 other faculty of the same nature, much more ample 
 and even infinite ; and seeing that I can frame the idea 
 of it, I discover, from this circumstance alone, that it 
 pertains to the nature of God. In the same way, if I 
 examine the faculty of memory or imagination, or any 
 other faculty I possess, I find none that is not small 
 and circumscribed, and in God immense [and infinite]. 
 It is the faculty of will only, or freedom of choice, 
 which I experience to be so great that I am unable to 
 conceive the idea of another that shall be more ample 
 and extended ; so that it is chiefly my will which leads 
 me to discern that I bear a certain image and simili- 
 tude of Deity. For although the faculty of will is in- 
 comparably greater in God than in myself, as well in 
 respect of the knowledge and power that are con- 
 joined with it, and that render it stronger and more 
 efficacious, as in respect of the object, since in him it 
 extends to a greater number of things, it does not, 
 nevertheless, appear to me greater, considered in itself 
 formally and precisely: for the power of will consists 
 only in this, that we are able to do or not to do the 
 same thing (that is, to affirm or deny, to pursue or 
 shun it), or rather in this alone, that in affirming or 
 denying, pursuing or shunning, what is proposed to us 
 by the understanding, we so act that we are not con- 
 scious of being determined to a particular action by 
 any external force. For, to the possession of freedom, 
 it is not necessary that I be alike indifferent towards 
 each of two contraries ; but, on the contrary, the more 
 I am inclined towards the one, whether because I 
 
OF TRUTH AND ERROR. 69 
 
 clearly know that in it there is the reason of truth and 
 goodness, or because God thus internally disposes my 
 thought, the more freely do I choose and embrace it; 
 and assuredly divine grace and natural knowledge, 
 very far from diminishing liberty, rather augment and 
 fortify it. But the indifference of which I am con- 
 scious when I am not impelled to one side rather than 
 to another for want of a reason, is the lowest grade of 
 liberty, and manifests defect or negation of knowledge 
 rather than perfection of will ; for if I always clearly 
 knew what was true and good, I should never have 
 any difficulty in determining what judgment I ought 
 to come to, and what choice I ought to make, and I 
 should thus be entirely free without ever being in- 
 different. 
 
 From all this I discover, however, that neither the j 
 power of willing, which I have received from God, is/ 
 of itself the source of my errors, for it is exceedingly 
 ample and perfect in its kind; nor even the power of 
 understanding, for as I conceive no object unless by 
 means of the faculty that God bestowed upon me, all 
 that I conceive is doubtless rightly conceived by me, 
 and it is impossible for me to be deceived in it. 
 
 Whence, then, spring my errors? They arise from 
 this cause alone, that I do not restrain the will, which 
 is of much wider range than the understanding, within 
 the same limits, but extend it even to things I do not 
 understand, and as the will is of itself indifferent to 
 such, it readily falls into error and sin by choosing the 
 false in room of the true, and evil instead of good. 
 
 For example, when I lately considered whether 
 aught really existed in the world, and found that be- 
 cause I considered this question, it very manifestly fol- 
 
70 MEDITATION IV. 
 
 lowed that I myself existed, I could not but judge that 
 what I so clearly conceived was true, not that I was 
 forced to this judgment by any external cause, but 
 simply because great clearness of the understanding 
 was succeeded by strong inclination in the will ; and I 
 believed this the more freely and spontaneously in pro- 
 portion as I was less indifferent with respect to it. 
 But now I not only know that I exist, in so far as I 
 am a thinking being, but there is likewise presented to 
 my mind a certain idea of corporeal nature; hence I 
 am in doubt as to whether the thinking nature which 
 is in me, or rather which I myself am, is different from 
 that corporeal nature, or whether both are merely one 
 and the same thing, and I here suppose that I am as 
 yet ignorant of any reason that would determine me to 
 adopt the one belief in preference to the other : whence 
 it happens that it is a matter of perfect indifference to 
 me which of the two suppositions I affirm or deny, or 
 whether I form any judgment at all in the matter. 
 
 This indifference, moreover, extends not only to 
 things of which the understanding has no knowledge 
 at all, but in general also to all those which it does not 
 discover with perfect clearness at the moment the will 
 is deliberating upon them; for, however probable the 
 conjectures may be that dispose me to form a judg- 
 ment in a particular matter, the simple knowledge that 
 these are merely conjectures, and not certain and in- 
 dubitable reasons, is sufficient to lead me to form one 
 that is directly the opposite. Of this I lately had 
 abundant experience, when I laid aside as false all that 
 I had before held for true, on the single ground that I 
 could in some degree doubt of it. But if I abstain from 
 judging of a thing when I do not conceive it with suf- 
 
OF TRUTH AND ERROR. 71 
 
 ficient clearness and distinctness, it is plain that I act 
 rightly, and am not deceived ; but if I resolve to deny 
 or affirm, I then do not make a right use of my free 
 will; and if I affirm what is false, it is evident that I 
 am deceived : moreover, even although I judge accord- 
 ing to truth, I stumble upon it by chance, and do not 
 therefore escape the imputation of a wrong use of my 
 freedom ; for it is a dictate of the natural light, that the 
 knowledge of the understanding ought always to pre- 
 cede the determination of the will. 
 
 And it is this wrong use of the freedom of the will 
 in which is found the privation that constitutes the 
 form of error. Privation, I say, is found in the act, in 
 so far as it proceeds from myself, but it does not exist 
 in the faculty which I received from God, nor even in 
 the act, in so far as it depends on him ; for I have as- 
 suredly no reason to complain that God has not given 
 me a greater power of intelligence or more perfect 
 natural light than he has actually bestowed, since it is 
 of the nature of a finite understanding not to compre- 
 hend many things, and of the nature of a created un- 
 derstanding to be finite ; on the contrary, I have every 
 reason to render thanks to God, who owed me nothing, 
 for having given me all the perfections I possess, and 
 I should be far from thinking that he has unjustly de- 
 prived me of, or kept back, the other perfections which 
 he has not bestowed upon me. 
 
 I have no reason, moreover, to complain because he 
 has given me a will more ample than my understand- 
 ing, since, as the will consists only of a single element, 
 and that indivisible, it would appear that this faculty 
 is of such a nature that nothing could be taken from it 
 [without destroying it] ; and certainly, the more exten- 
 
72 MEDITATION IV. 
 
 sive it is, the more cause I have to thank the goodness 
 of him who bestowed it upon me. 
 
 And, finally, I ought not also to complain that God 
 concurs with me in forming the acts of this will, or the 
 judgments in which I am deceived, because those acts 
 are wholly true and good, in so far as they depend on 
 God ; and the ability to form them is a higher degree 
 of perfection in my nature than the want of it would 
 be. With regard to privation, in which alone consists 
 the formal reason of error and sin, this does not re- 
 quire the concurrence of Deity, because it is not a 
 thing [or existence], and if it be referred to God as to 
 its cause, it ought not to be called privation, but nega- 
 tion, [according to the signification of these words in 
 the schools]. For in truth it is no imperfection in 
 Deity that he has accorded to me the power of giving 
 or withholding my assent from certain things of which 
 he has not put a clear and distinct knowledge in my 
 understanding; but it is doubtless an imperfection in 
 me that I do not use my freedom aright, and readily 
 give my judgment on matters which I only obscurely 
 and confusedly conceive. 
 
 I perceive, nevertheless, that it was easy for Deity 
 so to have constituted me as that I should never be de- 
 ceived, although I still remained free and possessed of 
 a limited knowledge, viz., by implanting in my under- 
 standing a clear and distinct knowledge of all the ob- 
 jects respecting which I should ever have to delib- 
 erate ; or simply by so deeply engraving on my mem- 
 ory the resolution to judge of nothing without previ- 
 ously possessing a clear and distinct conception of it, 
 that I should never forget it. And I easily understand 
 that, in so far as I consider myself as a single whole, 
 
OF TRUTH AND ERROR. 73 
 
 without reference to any other being in the universe, I 
 should have been much more perfect than I now am, 
 had Deity created me superior to error; but I cannot 
 therefore deny that it is not somehow a greater perfec- 
 tion in the universe, that certain of its parts are not 
 exempt from defect, as others are, than if they were all 
 perfectly alike. 
 
 And I have no right to complain because God, who 
 placed me in the world, was not willing that I should 
 sustain that character which of all others is the chief 
 and most perfect; I have even good reason to remain 
 satisfied on the ground that, if he has not given me the 
 perfection of being superior to error by the first means 
 I have pointed out above, which depends on a clear and 
 evident knowledge of all the matters regarding which 
 I can deliberate, he has at least left in my power the 
 other means, which is, firmly to retain the resolution 
 never to judge where the truth is not clearly known to 
 me: for, although I am conscious of the weakness of 
 not being able to keep my mind continually fixed on 
 the same thought, I can nevertheless, by attentive and 
 oft-repeated meditation, impress it so strongly on my 
 memory that I shall never fail to recollect it as often 
 as I require it, and I. can acquire in this way the habi- 
 tude of not erring ; and since it is in being superior to 
 error that the highest and chief perfection of man con- 
 sists, I deem that I have not gained little by this day's 
 meditation, in having discovered the source of error 
 and falsity. 
 
 And certainly this can be no other than what I have 
 now explained: for as often as I so restrain my will 
 within the limits of my knowledge, that it forms no 
 judgment except regarding objects which are clearly 
 
74 MEDITATION IV. 
 
 and distinctly represented to it by the understanding, 
 I can never be deceived ; because every clear and dis- 
 tinct conception is doubtless something, and as such 
 cannot owe its origin to nothing, but must of necessity 
 have God for its author — God, I say, who, as su- 
 premely perfect, cannot, without a contradiction, be 
 the cause of any error; and consequently it is neces- 
 sary to conclude that every such conception [or judg- 
 ment] is true. Nor have I merely learned to-day what 
 I must avoid to escape error, but also what I must do 
 to arrive at the knowledge of truth ; for I will as- 
 suredly reach truth if I only fix my attention suffi- 
 ciently on all the things I conceive perfectly, and sepa- 
 rate these from others which I conceive more con- 
 fusedly and obscurely : to which for the future I shall 
 give diligent heed. 
 
MEDITATION V. 
 
 OF THE ESSENCE OF MATERIAL THINGS ,* AND, AGAIN, OF 
 GOD ; THAT HE EXISTS. 
 
 Several other questions remain for consideration re- 
 specting the attributes of God and my own nature or 
 mind. I will, however, on some other occasion per- 
 haps resume the investigation of these. Meanwhile, 
 as I have discovered what must be done and what 
 avoided to arrive at the knowledge of truth, what I 
 have chiefly to do is to essay to emerge from the state 
 of doubt in which I have for some time been, and to 
 discover whether anything can be known with cer- 
 tainty regarding material objects. But before con- 
 sidering whether such objects as I conceive exist with- 
 out me, I must examine their ideas in so far as these 
 are to be found in my consciousness, and discover 
 which of them are distinct and which confused. 
 
 In the first place, I distinctly imagine that quantity 
 which the philosophers commonly call continuous, or 
 the extension in length, breadth, and depth that is in 
 this quantity, or rather in the object to which it is at- 
 tributed. Further, I can enumerate in it many diverse 
 parts, and attribute to each of these all sorts of sizes, 
 figures, situations, and local motions ; and, in fine, I 
 can assign to each of these motions all degrees of 
 duration. And I not only distinctly know these things 
 when I thus consider them in general ; but besides, by 
 a little attention, I discover innumerable particulars 
 75 
 
76 MEDITATION V. 
 
 respecting figures, numbers, motion, and the like, 
 which are so evidently true, and so accordant with my 
 nature, that when I now discover them I do not so much 
 appear to learn anything new, as to call to remem- 
 brance what I before knew, or for the first time to re- 
 mark what was before in my mind, but to which I had 
 not hitherto directed my attention. And what I here 
 find of most importance is, that I discover in my mind 
 innumerable ideas of certain objects, which cannot be 
 esteemed pure negations, although perhaps they pos- 
 sess no reality beyond my thought, and which are not 
 framed by me though it may be in my power to think, 
 or not to think them, but possess true and immutable 
 natures of their own. As, for example, when I im- 
 agine a triangle, although there is not perhaps and 
 never was in any place in the universe apart from my 
 thought one such figure, it remains true nevertheless 
 that this figure possesses a certain determinate nature, 
 form, or essence, which is immutable and eternal, and 
 not framed by me, nor in any degree dependent on 
 my thought ; as appears from the circumstance, that 
 diverse properties of the triangle may be demonstrated, 
 viz., that its three angles are equal to two right, that 
 its greatest side is subtended by its greatest angle, and 
 the like, which, whether I will or not, I now clearly 
 discern to belong to it, although before I did not at all 
 think of them, when, for the first time, I imagined a 
 triangle, and which accordingly cannot be said to have 
 been invented by me. Nor is it a valid objection to 
 allege, that perhaps this idea of a triangle came into 
 my mind by the medium of the senses, through my 
 having seen bodies of a triangular figure; for I am 
 able to form in thought an innumerable variety of 
 
OF THE ESSENCE OF MATERIAL THINGS. 77 
 
 figures with regard to which it cannot be supposed that 
 they were ever objects of sense, and I can nevertheless 
 demonstrate diverse properties of their nature no less 
 than of the triangle, all of which are assuredly true 
 since I clearly conceive them: and they are therefore 
 something, and not mere negations; for it is highly 
 evident that all that is true is something, [truth being 
 identical with existence] ; and I have already fully 
 shown the truth of the principle, that whatever is 
 clearly and distinctly known is true. And although 
 this had not been demonstrated, yet the nature of my 
 mind is such as to compel me to assent to what I 
 clearly conceive while I so conceive it; and I recollect 
 that even when I still strongly adhered to the objects 
 of sense, I reckoned among the number of the most 
 certain truths those I clearly conceived relating to 
 figures, numbers, and other matters that pertain to 
 arithmetic and geometry, and in general to the pure 
 mathematics. 
 
 But now if because I can draw from my thought the 
 idea of an object, it follows that all I clearly and dis- 
 tinctly apprehend to pertain to this object, does in 
 truth belong to it, may I not from this derive an argu- 
 ment for the existence of God ? It is certain that I no 
 less find the idea of a God in my consciousness, that is, 
 the idea of a being supremely perfect, than that of any 
 figure or number whatever : and I know with not less 
 clearness and distinctness that an [actual and] eternal 
 existence pertains to his nature than that all which is 
 demonstrable of any figure or number really belongs 
 to the nature of that figure or number ; and, therefore, 
 although all the conclusions of the preceding Medita- 
 tions were false, the existence of God would pass with 
 
7 8 MEDITATION V. 
 
 me for a truth at least as certain as I ever judged any 
 truth of mathematics to be, although indeed such a 
 doctrine may at first sight appear to contain more 
 sophistry than truth. For, as I have been accustomed 
 in every other matter to distinguish between existence 
 and essence, I easily believe that the existence can be 
 separated from the essence of God, and that thus God 
 may be conceived as not actually existing. But, never- 
 theless, when I think of it more attentively, it appears 
 that the existence can no more be separated from the 
 essence of God, than the idea of a mountain from that 
 of a valley, or the equality of its three angles to two 
 right angles, from the essence of a [rectilineal] tri- 
 angle; so that it is not less impossible to conceive a 
 God, that is, a being supremely perfect, to whom exist- 
 ence is awanting, or who is devoid of a certain perfec- 
 tion, than to conceive a mountain without a valley. 
 
 But though, in truth, I cannot conceive a God unless 
 as existing, any more than I can a mountain without a 
 valley, yet, just as it does not follow that there is any 
 mountain in the world merely because I conceive a 
 mountain with a valley, so likewise, though I conceive 
 God as existing, it does not seem to follow on that ac- 
 count that God exists ; for my thought imposes no 
 necessity on things; and as I may imagine a winged 
 horse, though there be none such, so I could perhaps 
 attribute existence to God, though no God existed. 
 But the cases are not analogous, and a fallacy lurks 
 under the semblance of this objection: for because I 
 cannot conceive a mountain without a valley, it does 
 not follow that there is any mountain or valley in ex- 
 istence, but simply that the mountain or valley, 
 whether they do or do not exist, are inseparable from 
 
OF THE ESSENCE OF MATERIAL THINGS. 79 
 
 each other ; whereas, on the other hand, because I can- 
 not conceive God unless as existing, it follows that ex- 
 istence is inseparable from him, and therefore that he 
 really exists : not that this is brought about by my 
 thought, or that it imposes any necessity on things, 
 but, on the contrary, the necessity which lies in the 
 thing itself, that is, the necessity of the existence of 
 God, determines me to think in this way : for it is not 
 in my power to conceive a God without existence, that 
 is, a being supremely perfect, and yet devoid of an ab- 
 solute perfection, as I am free to imagine a horse with 
 or without wings. 
 
 Nor must it be alleged here as an objection, that it is 
 in truth necessary to admit that God exists, after hav- 
 ing supposed him to possess all perfections, since exist- 
 ence is one of them, but that my original supposition 
 was not necessary; just as it is not necessary to think 
 that all quadrilateral figures can be inscribed in the 
 circle, since, if I supposed this, I should be constrained 
 to admit that the rhombus, being a figure of four sides, 
 can be therein inscribed, which, however, is manifestly 
 false. This objection is, I say, incompetent; for al- 
 though it may not be necessary that I shall at any time 
 entertain the notion of Deity, yet each time I happen 
 to think of a first and sovereign being, and to draw, so 
 to speak, the idea of him from the storehouse of the 
 mind, I am necessitated to attribute to him all kinds of 
 perfections, though I may not then enumerate them all, 
 nor think of each of them in particular. And this 
 necessity is sufficient, as soon as I discover that exist- 
 ence is a perfection, to cause me to infer the existence 
 of this first and sovereign being : just as it is not nec- 
 essary that I should ever imagine any triangle, but 
 
8o MEDITATION V. 
 
 whenever I am desirous of considering a rectilineal 
 figure composed of only three angles, it is absolutely 
 necessary to attribute those properties to it from which 
 it is correctly inferred that its three angles are not 
 greater than two right angles, although perhaps I may 
 not. then advert to this relation in particular. But 
 when I consider what figures are capable of being in- 
 scribed in the circle, it is by no means necessary to hold 
 that all quadrilateral figures are of this number; on 
 the contrary, I cannot even imagine such to be the case, 
 so long as I shall be unwilling to accept in thought 
 aught that I do not clearly and distinctly conceive: 
 and consequently there is a vast difference between 
 false suppositions, as is the one in question, and the 
 true ideas that were born with me, the first and chief 
 of which is the idea of God. For indeed I discern on 
 many grounds that this idea is not factitious, depend- 
 ing simply on my thought, but that it is the representa- 
 tion of a true and immutable nature : in the first place, 
 because I can conceive no other being, except God, to 
 whose essence existence [necessarily] pertains; in the 
 second, because it is impossible to conceive two or 
 more gods of this kind ; and it being supposed that one 
 such God exists, I clearly see that he must have existed 
 from all eternity, and will exist to all eternity ; and 
 finally, because I apprehend many other properties in 
 God, none of which I can either diminish or change. 
 
 But, indeed, whatever mode of probation I in the 
 end adopt, it always returns to this, that it is only the 
 things I clearly and distinctly conceive which have the 
 power of completely persuading me. And although, 
 of the objects I conceive in this manner, some, indeed, 
 are obvious to every one, while others are only dis- 
 
OF THE ESSENCE OF MATERIAL THINGS. 81 
 
 covered after close and careful investigation ; never- 
 theless, after they are once discovered, the latter are 
 not esteemed less certain than the former. Thus, for 
 example, to take the case of a right-angled triangle, al- 
 though it is not so manifest at first that the square of 
 the base is equal to the squares of the other two sides, 
 as that the base is opposite to the greatest angle; never- 
 theless, after it is once apprehended, we are as firmly- 
 persuaded of the truth of the former as of the latter. 
 And, with respect to God, if I were not pre-occupied 
 by prejudices, and my thought beset on all sides by the 
 continual presence of the images of sensible objects, I 
 should know nothing sooner or more easily than the 
 fact of his being. For is there any truth more clear 
 than the existence of a Supreme Being, or of God, see- 
 ing it is to his essence alone that [necessary and eter- 
 nal] existence pertains? And although the right con- 
 ception of this truth has cost me much close thinking, 
 nevertheless at present I feel not only as assured of it 
 as of what I deem most certain, but I remark further 
 that the certitude of all other truths is so absolutely 
 dependent on it, that without this knowledge it is im- 
 possible ever to know anything perfectly. 
 
 For although I am of such a nature as to be unable, 
 while I possess a very clear and distinct apprehension 
 of a matter, to resist the conviction of its truth, yet be- 
 cause my constitution is also such as to incapacitate me 
 from keeping my mind continually fixed on the same 
 object, and as I frequently recollect a past judgment 
 without at the same time being able to recall the 
 grounds of it, it may happen meanwhile that other rea- 
 sons are presented to me which would readily cause me 
 to change my opinion, if I did not know that God ex- 
 
82 MEDITATION V. 
 
 isted ; and thus I should possess no true and certain 
 knowledge, but merely vague and vacillating opinions. 
 Thus, for example, when I consider the nature of the 
 [rectilineal] triangle, it most clearly appears to me, 
 who have been instructed in the principles of geom- 
 etry, that its three angles are equal to two right angles, 
 and I find it impossible to believe otherwise, while I 
 apply my mind to the demonstration ; but as soon as I 
 cease from attending to the process of proof, although 
 I still remember that I had a clear comprehension of it, 
 yet I may readily come to doubt of the truth demon- 
 strated, if I do not know that there is a God : for I may 
 persuade myself that I have been so constituted by na- 
 ture as to be sometimes deceived, even in matters 
 which I think I apprehend with the greatest evidence 
 and certitude, especially when I recollect that I fre- 
 quently considered many things to be true and certain 
 which other reasons afterwards constrained me to 
 reckon as wholly false. 
 
 But after I have discovered that God exists, seeing 
 I also at the same time observed that all things depend 
 on him, and that he is no deceiver, and thence inferred 
 that all which I clearly and distinctly perceive is of 
 necessity true : although I no longer attend to the 
 grounds of a judgment, no opposite reason can be al- 
 leged sufficient to lead me to doubt of its truth, pro- 
 vided only I remember that I once possessed a clear 
 and distinct comprehension of it. My knowledge of it 
 thus becomes true and certain. And this same knowl- 
 edge extends likewise to whatever I remember to have 
 formerly demonstrated, as the truths of geometry and 
 the like : for what can be alleged against them to lead 
 me to doubt of them? Will it be that my nature is 
 
OF THE ESSENCE OF MATERIAL THINGS. 83 
 
 such that I may be frequently deceived ? But I al- 
 ready know that I cannot be deceived in judgments of 
 the grounds of which I possess a clear knowledge. 
 Will it be that I formerly deemed things to be true and 
 certain which I afterwards discovered to be false ? But 
 I had no clear and distinct knowledge of any of those 
 things, and, being as yet ignorant of the rule by which 
 I am assured of the truth of a judgment, I was led to 
 give my assent to them on grounds which I afterwards 
 discovered were less strong than at the time I imagined 
 them to be. What further objection, then, is there? 
 Will it be said that perhaps I am dreaming (an objec- 
 tion I lately myself raised), or that all the thoughts of 
 which I am now conscious have no more truth than the 
 reveries of my dreams? But although, in truth, I 
 should be dreaming, the rule still holds that all which 
 is clearly presented to my intellect is indisputably true. 
 And thus I very clearly see that the certitude and 
 truth of all science depends on the knowledge alone of 
 the true God, insomuch that, before I knew him, I 
 could have no perfect knowledge of any other thing. 
 And now that I know him, I possess the means of ac- 
 quiring a perfect knowledge respecting innumerable 
 matters, as well relative to God himself and other in- 
 tellectual objects as to corporeal nature, in so far as it 
 is the object of pure mathematics [which do not con- 
 sider whether it exists or not]. 
 
MEDITATION VI. 
 
 OF THE EXISTENCE OF MATERIAL THINGS, AND OF THE 
 
 REAL DISTINCTION BETWEEN THE MIND AND BODY 
 
 OF MAN. 
 
 There now only remains the inquiry as to whether 
 material things exist. With regard to this question, I 
 at least know with certainty that such things may exist, 
 in as far as they constitute the object of the pure 
 mathematics, since, regarding them in this aspect, I 
 can conceive them clearly and distinctly. For there 
 can be no doubt that God possesses the power of pro- 
 ducing all the objects I am able distinctly to conceive, 
 and I never considered anything impossible to him, un- 
 less when I experienced a contradiction in the attempt 
 to conceive it aright. Further, the faculty of imagina- 
 tion which I possess, and of which I am conscious that 
 I make use when I apply myself to the consideration of 
 material things, is sufficient to persuade me of their 
 existence: for, when I attentively consider what im- 
 agination is, I rind that! it is simply a certain applica- 
 tion of the cognitive faculty (facilitas cognoscitiva) to 
 a body which is immediately present to it, and which 
 therefore exists. 
 
 And to render this quite clear, I remark, in the first 
 place, the difference that subsists between imagination 
 and pure intellection [or conception]. For example, 
 when I imagine a triangle I not only conceive (intel- 
 ligo) that it is a figure comprehended by three lines, 
 84 
 
OF THE EXISTENCE OF MATERIAL THINGS. 85 
 
 but at the same time also I look upon (intueor) these 
 three lines as present by the power and internal appli- 
 cation of my mind (acie mentis), and this is what I call 
 imagining. But if I desire to think of a chiliogon, I 
 indeed rightly conceive that it is a figure composed of 
 a thousand sides, as easily as I conceive that a triangle 
 is a figure composed of only three sides ; but I cannot 
 imagine the thousand sides of a chiliogon as I do the 
 three sides of a triangle, nor, so to speak, view them as 
 present [with the eyes of my mind]. And although, 
 in accordance with the habit I have of always imagin- 
 ing something when I think of corporeal things, it may 
 happen that, in conceiving a chiliogon, I confusedly 
 represent some figure to myself, yet it is quite evident 
 that this is not a chiliogon, since it in no wise differs 
 from that which I would represent to myself, if I were 
 to think of a myriogon, or any other figure of many 
 sides ; nor would this representation be of any use in 
 discovering and unfolding the properties that consti- 
 tute the difference between a chiliogon and other poly- 
 gons. But if the question turns on a pentagon, it is 
 quite true that I can conceive its figure, as well as that 
 of a chiliogon, without the aid of imagination ; but I 
 can likewise imagine it by applying the attention of my 
 mind to its five sides, and at the same time to the area 
 which they contain. Thus I observe that a special ef- 
 fort of mind is necessary to the act of imagination, 
 which is not required to conceiving or understanding 
 (ad intelligendum) ; and this special exertion of mind 
 clearly shows the difference between imagination and 
 pure intellection (imaginatio et intellect™ pur a). I 
 remark, besides, that this power of imagination which 
 I possess, in as far as it differs from the power of con- 
 
86 MEDITATION VI. 
 
 ceiving, is in no way necessary to my [nature or] es- 
 sence, that is, to the essence of my mind ; for although 
 I did not possess it, I should still remain the same that 
 I now am, from which it seems we may conclude that 
 it depends on something different from the mind. And 
 I easily understand that, if some body exists, with 
 which my mind is so conjoined and united as to be 
 able, as it were, to consider it when it chooses, it may 
 thus imagine corporeal objects; so that this mode of 
 thinking differs from pure intellection only in this re- 
 spect, that the mind in conceiving turns in some way 
 upon itself, and considers some one of the ideas it pos- 
 sesses within itself ; but in imagining it turns towards 
 the body, and contemplates in it some object conformed 
 to the idea which it either of itself conceived or appre- 
 hended by sense. I easily understand, I say, that 
 imagination may be thus formed, if it is true that there 
 are bodies ; and because I find no other obvious mode 
 of explaining it, I thence, with probability, conjecture 
 that they exist, but only with probability ; and although 
 I carefully examine all things, nevertheless I do not 
 find that, from the distinct idea of corporeal nature I 
 have in my imagination, I can necessarily infer the 
 existence of any body. 
 
 But I am accustomed to imagine many other objects 
 besides that corporeal nature which is the object of the 
 pure mathematics, as, for example, colours, sounds, 
 tastes, pain, and the like, although with less distinct- 
 ness ; and, inasmuch as I perceive these objects much 
 better by the senses, through the medium of which and 
 of memory, they seem to have reached the imagination, 
 I believe that, in order the more advantageously to 
 examine them, it is proper I should at the same time 
 
OF THE EXISTENCE OF MATERIAL THINGS. 87 
 
 examine what sense-perception is, and inquire whether 
 from those ideas that are apprehended by this mode of 
 thinking (consciousness), I cannot obtain a certain 
 proof of the existence of corporeal objects. 
 
 And, in the first place, I will recall to my mind the 
 things I have hitherto held as true, because perceived 
 by the senses, and the foundations upon which my be- 
 lief in their truth rested ; I will, in the second place, 
 examine the reasons that afterwards constrained me to 
 doubt of them ; and, finally, I will consider what of 
 them I ought now to believe. 
 
 Firstly, then, I perceived that I had a head, hands, 
 feet, and other members composing that body which I 
 considered as part, or perhaps even as a whole, of my- 
 self. I perceived further, that that body was placed 
 among many others, by which it was capable of being 
 affected in diverse ways, both beneficial and hurtful ; 
 and what was beneficial I remarked by a certain sensa- 
 tion of pleasure, and what was hurtful by a sensation 
 of pain. And, besides this pleasure and pain, I was 
 likewise conscious of hunger, thirst, and other appe- 
 tites, as well as certain corporeal inclinations towards 
 joy, sadness, anger, and similar passions. And, out of 
 myself, besides the extension, figure, and motions of 
 bodies, I likewise perceived in them hardness, heat, and 
 the other tactile qualities, and, in addition, light, 
 colours, odours, tastes, and sounds, the variety of 
 which gave me the means of distinguishing the sky, 
 the earth, the sea, and generally all the other bodies, 
 from one another. And certainly, considering the 
 ideas of all these qualities, which were presented to my 
 mind, and which alone I properly and immediately per- 
 ceived, it was not without reason that I thought I per- 
 
88 MEDITATION VI. 
 
 ceived certain objects wholly different from my 
 thought, namely, bodies from which those ideas pro- 
 ceeded ; for I was conscious that the ideas were pre- 
 sented to me without my consent being required, so 
 that I could not perceive any object, however desirous 
 I might be, unless it were present to the organ of sense ; 
 and it was wholly out of my power not to perceive it 
 when it was thus present. And because the ideas I 
 perceived by the senses were much more lively and 
 clear, and even, in their own way, more distinct than 
 any of those I could of myself frame by meditation, or 
 which I found impressed on my memory, it seemed 
 that they could not have proceeded from myself, and 
 must therefore have been caused in me by some other 
 objects ; and as of those objects I had no knowledge be- 
 yond what the ideas themselves gave me, nothing was 
 so likely to occur to my mind as the supposition that 
 the objects were similar to the ideas which they caused. 
 And because I recollected also that I had formerly 
 trusted to the senses, rather than to reason, and that 
 the ideas which I myself formed were not so clear as 
 those I perceived by sense, and that they were even for 
 the most part composed of parts of the latter, I was 
 readily persuaded that I had no idea in my intellect 
 which had not formerly passed through the senses. 
 Nor was I altogether wrong in likewise believing that 
 that body which, by a special right, I called my own, 
 pertained to me more properly and strictly than any of 
 the others ; for in truth, I could never be separated 
 from it as from other bodies : I felt in it and on account 
 of it all my appetites and affections, and in fine I was 
 affected in its parts by pain and the titillation of pleas- 
 ure, and not in the parts of the other bodies that were 
 
OF THE EXISTENCE OF MATERIAL THINGS. 89 
 
 separated from it. But when I inquired into the rea- 
 son why, from this I know not what sensation of pain, 
 sadness of mind should follow, and why from the sen- 
 sation of pleasure joy should arise, or why this inde- 
 scribable twitching of the stomach, which I call hun- 
 ger, should put me in mind of taking food, and the 
 parchedness of the throat of drink, and so in other 
 cases, I was unable to give any explanation, unless that 
 I was so taught by nature; for there is assuredly no 
 affinity, at least none that I am able to comprehend, be- 
 tween this irritation of the stomach and the desire of 
 food, any more than between the perception of an ob- 
 ject that causes pain and the consciousness of sadness 
 which springs from the perception. And in the same 
 way it seemed to me that all the other judgments I had 
 formed regarding the objects of sense, were dictates of 
 nature; because I remarked that those judgments were 
 formed in me, before I had leisure to weigh and con- 
 sider the reasons that might constrain me to form 
 them. 
 
 But, afterwards, a wide experience by degrees 
 sapped the faith I had reposed in my senses ; for I fre- 
 quently observed that towers, which at a distance 
 seemed round, appeared square when more closely 
 viewed, and that colossal figures, raised on the summits 
 of these towers, looked like small statues, when viewed 
 from the bottom of them ; and, in other instances with- 
 out number, I also discovered error in judgments 
 founded on the external senses ; and not only in those 
 founded on the external, but even in those that rested 
 on the internal senses ; for is there aught more internal 
 than pain ? and yet I have sometimes been informed by 
 parties whose arm or leg had been amputated, that 
 
go MEDITATION VI. 
 
 they still occasionally seemed to feel pain in that part 
 of the body which they had lost, — a circumstance that 
 led me to think that I could not be quite certain even 
 that any one of my members was affected when I felt 
 pain in it. And to these grounds of doubt I shortly 
 afterwards also added two others of very wide gener- 
 ality : the first of them was that I believed I never per- 
 ceived anything when awake which I could not oc- 
 casionally think I also perceived when asleep, and as I 
 do not believe that the ideas I seem to perceive in my 
 sleep proceed from objects external to me, I did not 
 any more observe any ground for believing this of such 
 as I seem to perceive when awake ; the second was that 
 since I was as yet ignorant of the author of my being, 
 or at least supposed myself to be so, I saw nothing to 
 prevent my having been so constituted by nature as 
 that I should be deceived even in matters that appeared 
 to me to possess the greatest truth. And, with respect 
 to the grounds on which I had before been persuaded 
 of the existence of sensible objects, I had no great diffi- 
 culty in finding suitable answers to them ; for as nature 
 seemed to incline me to many things from which reason 
 made me averse, I thought that I ought not to confide 
 much in its teachings. And although the perceptions 
 of the senses were not dependent on my will, I did not 
 think that I ought on that ground to conclude that they 
 proceeded from things different from myself, since per- 
 haps there might be found in me some faculty, though 
 hitherto unknown to me, which produced them. 
 
 But now that I begin to know myself better, and to 
 discover more clearly the author of my being, I do not, 
 indeed, think that I ought rashly to admit all which the 
 senses seem to teach, nor, on the other hand, is it my 
 
OF THE EXISTENCE OF MATERIAL THINGS. 91 
 
 conviction that I ought to doubt in general of their 
 teachings. 
 
 And, firstly, because I know that all which I clearly 
 and distinctly conceive can be produced by God exactly 
 as I conceive it, it is sufficient that I am able clearly 
 and distinctly to conceive one thing apart from another, 
 in order to be certain that the one is different from the 
 other, seeing they may at least be made to exist sepa- 
 rately, by the omnipotence of God ; and it matters not 
 by what power this separation is made, in order to be 
 compelled to judge them different; and, therefore, 
 merely because I know with certitude that I exist, and 
 because, in the meantime, I do not observe that aught 
 necessarily belongs to my nature or essence beyond my 
 being a thinking thing, I rightly conclude that my es- 
 sence consists only in my being a thinking thing, [or a 
 substance whose whole essence or nature is merely 
 thinking]. And although I may, or rather, as I will 
 shortly say, although I certainly do possess a body with 
 which I am very closely conjoined; nevertheless, be- 
 cause, on the one hand, I have a clear and distinct idea 
 of myself, in as far as I am only a thinking and unex- 
 tended thing, and as, on the other hand, I possess a 
 distinct idea of body, in as far as it is only an extended 
 and unthinking thing, it is certain that I, [that is, my 
 mind, by which I am what I am], is entirely and truly 
 distinct from my body, and may exist without it. 
 
 Moreover, I find in myself diverse faculties of think- 
 ing that have each their special mode: for example, I 
 find I possess the faculties of imagining and perceiv- 
 ing, without which I can indeed clearly and distinctly 
 conceive myself as entire, but I cannot reciprocally con- 
 ceive them without conceiving myself, that is to say, 
 
92 MEDITATION VI. 
 
 without an intelligent substance in which they reside, 
 for [in the notion we have of them, or to use the terms 
 of the schools] in their formal concept, they comprise 
 some sort of intellection ; whence I perceive that they 
 are distinct from myself as modes are from things. I 
 remark likewise certain other faculties, as the power of 
 changing place, of assuming diverse figures, and the 
 like, that cannot be conceived and cannot therefore 
 exist, any more than the preceding, apart from a sub- 
 stance in which they inhere. It is very evident, how- 
 ever, that these faculties, if they really exist, must be- 
 long to some corporeal or extended substance, since in 
 their clear and distinct concept there is contained some 
 sort of extension, but no intellection at all. Farther, 
 I cannot doubt but that there is in me a certain passive 
 faculty of perception, that is, of receiving and taking 
 knowledge of the ideas of sensible things; but this 
 would be useless to me, if there did not also exist in 
 me, or in some other thing, another active faculty capa- 
 ble of forming and producing those ideas. But this 
 active faculty cannot be in me [in as far as I am but a 
 thinking thing], seeing that it does not presuppose 
 thought, and also that those ideas are frequently pro- 
 duced in my mind without my contributing to it in any 
 way, and even frequently contrary to my will. This 
 faculty must therefore exist in some substance differ- 
 ent from me, in which all the objective reality of the 
 ideas that are produced by this faculty, is contained 
 formally or eminently, as I before remarked ; and this 
 substance is either a body, that is to say, a corporeal 
 nature in which is contained formally [and in effect] 
 all that is objectively [and by representation] in those 
 ideas ; or it is God himself, or some other creature, of 
 
OF THE EXISTENCE OF MATERIAL THINGS. 93 
 
 a rank superior to body, in which the same is contained 
 eminently. But as God is no deceiver, it is manifest 
 that he does not of himself and immediately communi- 
 cate those ideas to me, nor even by the intervention of 
 any creature in which their objective reality is not for- 
 mally, but only eminently, contained. For as he has 
 given me no faculty whereby I can discover this to be 
 the case, but, on the contrary, a very strong inclination 
 to believe that those ideas arise from corporeal objects, 
 I do not see how he could be vindicated from the 
 charge of deceit, if in truth they proceeded from any 
 other source, or were produced by other causes than 
 corporeal things : and accordingly it must be con- 
 cluded, that corporeal objects exist. Nevertheless 
 they are not perhaps exactly such as we perceive by the 
 senses, for their comprehension by the senses is, in 
 many instances, very obscure and confused ; but it is at 
 least necessary to admit that all which I clearly and 
 distinctly conceive as in them, that is, generally speak- 
 ing, all that is comprehended in the object of specula- 
 tive geometry, really exists external to me. 
 
 But with respect to other things which are either only 
 particular, as, for example, that the sun is of such a 
 size and figure, etc., or are conceived with less clearness 
 and distinctness, as light, sound, pain, and the like, al- 
 though they are highly dubious and uncertain, never- 
 theless on the ground alone that God is no deceiver, 
 and that consequently he has permitted no falsity in 
 my opinions which he has not likewise given me a 
 faculty of correcting, I think I may with safety con- 
 clude that I possess in myself the means of arriving at 
 the truth. And, in the first place, it cannot be doubted 
 that in each of the dictates of nature there is some 
 
94 MEDITATION VI. 
 
 truth : for by nature, considered in general, I now un- 
 derstand nothing more than God himself, or the order 
 and disposition established by God in created things ; 
 and by my nature in particular I understand the assem- 
 blage of all that God has given me. 
 
 But there is nothing which that nature teaches me 
 more expressly [or more sensibly] than that I have a 
 body which is ill affected when I feel pain, and stands 
 in need of food and drink when I experience the sensa- 
 tions of hunger and thirst, etc. And therefore I ought 
 not to doubt but that there is some truth in these infor- 
 mations. 
 
 Nature likewise teaches me by these sensations of 
 pain, hunger, thirst, etc., that I am not only lodged in 
 my body as a pilot in a vessel, but that I am besides so 
 intimately conjoined, and as it were intermixed with it, 
 that my mind and body compose a certain unity. For 
 if this were not the case, I should not feel pain when 
 my body is hurt, seeing I am merely a thinking thing, 
 but should perceive the wound by the understanding 
 alone, just as a pilot perceives by sight when any part 
 of his vessel is damaged ; and when my body has need 
 of food or drink, I should have a clear knowledge of 
 this, and not be made aware of it by the confused sen- 
 sations of hunger and thirst : for, in truth, all these sen- 
 sations of hunger, thirst, pain, etc., are nothing more 
 than certain confused modes of thinking, arising from 
 the union and apparent fusion of mind and body. 
 
 Besides this, nature teaches me that my own body is 
 surrounded by many other bodies, some of which I 
 have to seek after, and others to shun. And indeed, as 
 I perceive different sorts of colours, sounds, odours, 
 tastes, heat, hardness, etc., I safely conclude that there 
 
OF THE EXISTENCE OF MATERIAL THINGS. 95 
 
 are in the bodies from which the diverse perceptions of 
 the senses proceed, certain varieties corresponding to 
 them, although, perhaps, not in reality like them ; and 
 since, among these diverse perceptions of the senses, 
 some are agreeable, and others disagreeable, there can 
 be no doubt that my body, or rather my entire self, in 
 as far as I am composed of body and mind, may be 
 variously affected, both beneficially and hurtfully, by 
 surrounding bodies. . 
 
 But there are many other beliefs which, though 
 seemingly the teaching of nature, are not in reality so, 
 but which obtained a place in my mind through a habit 
 of judging inconsiderately of things. It may thus 
 easily happen that such judgments shall contain error : 
 thus, for example, the opinion I have that all space in 
 which there is nothing to affect [or make an impression 
 on] my senses is void ; that in a hot body there is some- 
 thing in every respect similar to the idea of heat in my 
 mind ; that in a white or green body there is the same 
 whiteness or greenness which I perceive ; that in a bit- 
 ter or sweet body there is the same taste, and so in other 
 instances ; that the stars, towers, and all distant bodies, 
 are of the same size and figure as they appear to our 
 eyes, etc. But that I may avoid everything like indis- 
 tinctness of conception, I must accurately define what I 
 properly understand by being taught by nature. For 
 nature is here taken in a narrower sense than when it 
 signifies the sum of all the things which God has given 
 me ; seeing that in that meaning the notion compre- 
 hends much that belongs only to the mind [to which I 
 am not here to be understood as referring when I use 
 the term nature] ; as, for example, the notion I have of 
 the truth, that what is done cannot be undone, and all 
 
gô MEDITATION VI. 
 
 the other truths I discern by the natural light [without 
 the aid of the body] ; and seeing that it comprehends 
 likewise much besides that belongs only to body, and is 
 not here any more contained under the name nature, as 
 the quality of heaviness, and the like, of which I do not 
 speak, — the term being reserved exclusively to desig- 
 nate the things which God has given to me as a being 
 composed of mind and body. But nature, taking the 
 term in the sense explained, teaches me to shun what 
 causes in me the sensation of pain, and to pursue what 
 affords me the sensation of pleasure, and other things 
 of this sort ; but I do not discover that it teaches me, in 
 addition to this, from these diverse perceptions of the 
 senses, to draw any conclusions respecting external ob- 
 jects without a previous [careful and mature] consid- 
 eration of them by the mind ; for it is, as appears to me, 
 the office of the mind alone, and not of the composite 
 whole of mind and body, to discern the truth in those 
 matters. Thus, although the impression a star makes 
 on my eye is not larger than that from the flame of a 
 candle, I do not, nevertheless, experience any real or 
 positive impulse determining me to believe that the star 
 is not greater than the flame ; the true account of the 
 matter being merely that I have so judged from my 
 youth without any rational ground. And, though on 
 approaching the fire I feel heat, and even pain on ap- 
 proaching it too closely, I have, however, from this no 
 ground for holding that something resembling the heat 
 I feel is in the fire, any more than that there is some- 
 thing similar to the pain ; all that I have ground for be- 
 lieving is, that there is something in it, whatever it may 
 be, which excites in me those sensations of heat or pain. 
 So also, although there are spaces in which I find noth- 
 
OF THE EXISTENCE OF MATERIAL THINGS. 97 
 
 ing to excite and affect my senses, I must not therefore 
 conclude that those spaces contain in them no body ; for 
 I see that in this, as in many other similar matters, I 
 have been accustomed to pervert the order of nature, 
 because these perceptions of the senses, although given 
 me by nature merely to signify to my mind what things 
 are beneficial and hurtful to the composite whole of 
 which it is a part, and being sufficiently clear and dis- 
 tinct for that purpose, are nevertheless used by me as 
 infallible rules by which to determine immediately the 
 essence of the bodies that exist out of me, of which they 
 can of course afford me only the most obscure and con- 
 fused knowledge. 
 
 But I have already sufficiently considered how it hap- 
 pens that, notwithstanding the supreme goodness of 
 God, there is falsity in my judgments. A difficulty, 
 however, here presents itself, respecting the things 
 which I am taught by nature must be pursued or 
 avoided, and also respecting the internal sensations in 
 which I seem to have occasionally detected error, [and 
 thus to be directly deceived by nature] : thus, for exam- 
 ple, I may be so deceived by the agreeable taste of some 
 viand with which poison has been mixed, as to be in- 
 duced to take the poison. In this case, however, nature 
 may be excused, for it simply leads me to desire the 
 viand for its agreeable taste, and not the poison, which 
 is unknown to it ; and thus we can infer nothing from 
 this circumstance beyond that our nature is not om- 
 niscient ; at which there is assuredly no ground for sur- 
 prise, since, man being of a finite nature, his knowl- 
 edge must likewise be of limited perfection. But we 
 also not unfrequently err in that to which we are di- 
 rectly impelled by nature, as is the case with invalids 
 
98 MEDITATION VI. 
 
 who desire drink or food that would be hurtful to them. 
 It will here, perhaps, be alleged that the reason why 
 such persons are deceived is that their nature is cor- 
 rupted; but this leaves the difficulty untouched, for a 
 sick man is not less really the creature of God than a 
 man who is in full health ; and therefore it is as repug- 
 nant to the goodness of God that the nature of the 
 former should be .deceitful as it is for that of the latter 
 to be so. And, as a clock, composed of wheels and 
 counter weights, observes not the less accurately all the 
 laws of nature when it is ill made, and points out the 
 hours incorrectly, than when it satisfies the desire of 
 the maker in every respect ; so likewise if the body of 
 man be considered as a kind of machine, so made up 
 and composed of bones, nerves, muscles, veins, blood, 
 and skin, that although there were in it no mind, it 
 would still exhibit the same motions which it at present 
 manifests involuntarily, and therefore without the aid 
 of the mind, [and simply by the dispositions of its or- 
 gans], I easily discern that it would also be as natural 
 for such a body, supposing it dropsical, for example, 
 to experience the parchedness of the throat that is 
 usually accompanied in the mind by the sensation of 
 thirst, and to be disposed by this parchedness to move 
 its nerves and its other parts in the way required for 
 drinking, and thus increase its malady and do itself 
 harm, as it is natural for it, when it is not indisposed to 
 be stimulated to drink for its good by a similar cause ; 
 and although looking to the use for which a clock was 
 destined by its maker, I may say that it is deflected 
 from its proper nature when it incorrectly indicates the 
 hours, and on the same principle, considering the ma- 
 chine of the human body as having been formed by God 
 
OF THE EXISTENCE OF MATERIAL THINGS. 99 
 
 for the sake of the motions which it usually manifests, 
 although I may likewise have ground for thinking that 
 it does not follow the order of its nature when the 
 throat is parched and drink does not tend to its preser- 
 vation, nevertheless I yet plainly discern that this latter 
 acceptation of the term nature is very different from the 
 other ; for this is nothing more than a certain denomi- 
 nation, depending entirely on my thought, and hence 
 called extrinsic, by which I compare a sick man and an 
 imperfectly constructed clock with the idea I have of a 
 man in good health and a well made clock; while by 
 the other acceptation of nature is understood something 
 which is truly found in things, and therefore possessed 
 of some truth. 
 
 But certainly, although in respect of a dropsical 
 body, it is only by way of exterior denomination that 
 we say its nature is corrupted, when, without requiring 
 drink, the throat is parched ; yet, in respect of the com- 
 posite whole, that is, of the mind in its union with the 
 body, it is not a pure denomination, but really an error 
 of nature, for it to feel thirst when drink would be hurt- 
 ful to it : and, accordingly, it still remains to be consid- 
 ered why it is that the goodness of God does not pre- 
 vent the nature of man thus taken from being falla- 
 cious. 
 
 To commence this examination accordingly, I here 
 remark, in the first place, that there is a vast difference 
 between mind and body, in respect that body, from its - 
 nature, is always divisible, and that mind is entirely 
 indivisible. For in truth, when I consider the mind, 
 that is, when I consider myself in so far only as I am 
 a thinking thing, I can distinguish in myself no parts, 
 but I very clearly discern that I am somewhat abso- 
 
ioo MEDITATION VI. 
 
 lutely one and entire ; and although the whole mind 
 seems to be united to the whole body, yet, when a foot, 
 an arm, or any other part is cut off, I am conscious that 
 nothing has been taken from my mind ; nor can the 
 faculties of willing, perceiving, conceiving, etc., prop- 
 erly be called its parts, for it is the same mind that is 
 exercised [all entire] in willing, in perceiving, and in 
 conceiving, etc. But quite the opposite holds in cor- 
 poreal or extended things ; for I cannot imagine any 
 one of them [how small soever it may be], which I 
 cannot easily sunder in thought, and which, therefore, 
 I do not know to be divisible. This would be suffi- 
 cient to teach me that the mind or soul of man is en- 
 tirely different from the body, if I had not already been 
 apprised of it on other grounds. 
 
 I remark, in the next place, that the mind does not 
 immediately receive the impression from all the parts of 
 the body, but only from the brain, or perhaps even from 
 one small part of it, viz., that in which the common 
 sense (sensus communis) is said to be, which as often 
 as it is affected in the same way, gives rise to the same 
 perception in the mind, although meanwhile the other 
 parts of the body may be diversely disposed, as is 
 proved by innumerable experiments, which it is un- 
 necessary here to enumerate. 
 
 I remark, besides, that the nature of body is such 
 that none of its parts can be moved by another part a 
 little removed from the other, which cannot likewise be 
 moved in the same way by any one of the parts that lie 
 between those two, although the most remote part does 
 not act at all. As, for example, in the cord a, b, c, d, 
 [which is in tension], if its last part d, be pulled, the 
 first part a, will not be moved in a different way than 
 
OF THE EXISTENCE OF MATERIAL THINGS, iox 
 
 it would be were one of the intermediate parts b or c 
 to be pulled, and the last part d meanwhile to remain 
 fixed. And in the same way, when I feel pain in the 
 foot, the science of physics teaches me that this sensa- 
 tion is experienced by means of the nerves dispersed 
 over the foot, which, extending like cords from it to 
 the brain, when they are contracted in the foot, con- 
 tract at the same time the inmost parts of the brain in 
 which they have their origin, and excite in these parts 
 a certain motion appointed by nature to cause in the 
 mind a sensation of pain, as if existing in the foot : but 
 as these nerves must pass through the tibia, the leg, the 
 loins, the back, and neck, in order to reach the brain, it 
 may happen that although their extremities in the foot 
 are not affected, but only certain of their parts that pass 
 through the loins or neck, the same movements, never- 
 theless, are excited in the brain by this motion as would 
 have been caused there by a hurt received in the foot, 
 and hence the mind will necessarily feel pain in the 
 foot, just as if it had been hurt ; and the same is true 
 of all the other perceptions of our senses. 
 
 I remark, finally, that as each of the movements that 
 are made in the part of the brain by which the mind is 
 immediately affected, impresses it with but a single sen- 
 sation, the most likely supposition in the circumstances 
 is, that this movement causes the mind to experience, 
 among all the sensations which it is capable of impress- 
 ing upon it, that one which is the best fitted, and gen- 
 erally the most useful for the preservation of the 
 human body when it is in full health. But experience 
 shows us that all the perceptions which nature has 
 given us are of such a kind as I have mentioned ; and 
 accordingly, there is nothing found in them that does 
 
102 MEDITATION VI. 
 
 not manifest the power and goodness of God. Thus, 
 for example, when the nerves of the foot are violently 
 or more than usually Shaken, the motion passing 
 through the medulla of the spine to the innermost parts 
 of the brain affords a sign to the mind on which it ex- 
 periences a sensation, viz., of pain, as if it were in the 
 foot, by which the mind is admonished and excited to 
 do its utmost to remove the cause of it as dangerous 
 and hurtful to the foot. It is true that God could have 
 so constituted the nature of man as that the same mo- 
 tion in the brain would have informed the mind of 
 something altogether different: the motion might, for 
 example, have been the occasion on which the mind be- 
 came conscious of itself, in so far as it is in the brain, 
 or in so far as it is in some place intermediate between 
 the foot and the brain, or, finally, the occasion on which 
 it perceived some other object quite different, what- 
 ever that might be ; but nothing of all this would have 
 so well contributed to the preservation of the body as 
 that which the mind actually feels. In the same way, 
 when we stand in need of drink, there arises from this 
 want a certain parchedness in the throat that moves its 
 nerves, and by means of them the internal parts of the 
 brain ; and this movement affects the mind with the sen- 
 sation of thirst, because there is nothing on that oc- 
 casion which is more useful for us than to be made 
 aware that we have need of drink for the preservation 
 of our health ; and so in other instances. 
 
 Whence it is quite manifest that, notwithstanding 
 the sovereign goodness of God, the nature of man, in 
 so far as it is composed of mind and body, cannot but 
 be sometimes fallacious. For, if there is any cause 
 which excites, not in the foot, but in some one of the 
 
OF THE EXISTENCE OF MATERIAL THINGS. 103 
 
 parts of the nerves that stretch from the foot to the 
 brain, or even in the brain itself, the same movement 
 that is ordinarily created when the foot is ill affected, 
 pain will be felt, as it were, in the foot, and the sense 
 will thus be naturally deceived ; for as the same move- 
 ment in the brain can but impress the mind with the 
 same sensation, and as this sensation is much more fre- 
 quently excited by a cause which hurts the foot than by 
 one acting in a different quarter, it is reasonable that it 
 should lead the mind to feel pain in the foot rather than 
 in any other part of the body. And if it sometimes 
 happens that the parchedness of the throat does not 
 arise, as is usual, from drink being necessary for the 
 health of the body, but from quite the opposite cause, 
 as is the case with the dropsical, yet it is much better 
 that it should be deceitful in that instance, than if, on 
 the contrary, it were continually fallacious when the 
 body is well-disposed ; and the same holds true in other 
 cases. 
 
 And certainly this consideration is of great service, 
 not only in enabling me to recognize the errors to 
 which my nature is liable, but likewise in rendering it 
 more easy to avoid or correct them : for, knowing that 
 all my senses more usually indicate to me what is true 
 than what is false, in matters relating to the advantage 
 of the body, and being able almost always to make 
 use of more than a single sense in examining the same 
 object, and besides this, being able to use my memory 
 in connecting present with past knowledge, and my un- 
 derstanding which has already discovered all the causes 
 of my errors, I ought no longer to fear that falsity 
 maybe met with in what is daily presented to me by the 
 senses. And I ought to reject all the doubts of those 
 
104 'MEDITATION VI. 
 
 bygone days, as hyperbolical and ridiculous, especially 
 the general uncertainty respecting sleep, which I could 
 not distinguish from the waking state : for I now find 
 a very marked difference between the two states, in re- 
 spect that our memory can never connect our dreams 
 with each other and with the course of life, in the way 
 it is in the habit of doing with events that occur when 
 we are awake. And, in truth, if some one, when I am 
 awake, appeared to me all of a sudden and as suddenly 
 disappeared, as do the images I see in sleep, so that I 
 could not observe either whence he came or whither he 
 went, I should not without reason esteem it either a 
 spectre or phantom formed in my brain, rather than a 
 real man. But when I perceive objects with regard to 
 which I can distinctly determine both the place whence 
 they come, and that in which they are, and the time at 
 which they appear to me, and when, without interrup- 
 tion, I can connect the perception I have of them with 
 the whole of the other parts of my life, I am perfectly 
 sure that what I thus perceive occurs while I am awake 
 and not during sleep. And I ought not in the least de- 
 gree to doubt of the truth of those presentations, if, 
 after having called together all my senses, my memory, 
 and my understanding for the purpose of examining 
 them, no deliverance is given by any one of these facul- 
 ties which is repugnant to that of any other : for since 
 God is no deceiver, it necessarily follows that I am not 
 herein deceived. But because the necessities of action 
 frequently oblige us to come to a determination before 
 we have had leisure for so careful an examination, it 
 must be confessed that the life of man is frequently 
 obnoxious to error with respect to individual objects ; 
 and we must, in conclusion, acknowledge the weakness 
 of our nature. 
 
SELECTIONS 
 
 THE PRINCIPLES OF PHILOSOPHY 
 
 DESCARTES 
 
 TRANSLATED FROM THE LATIN AND COLLATED 
 WITH THE FRENCH 
 
LETTER OF THE AUTHOR 
 
 TO THE 
 FRENCH TRANSLATOR OF THE PRINCIPLES OF PHILO- 
 SOPHY SERVING FOR A PREFACE. 
 
 Sir, — The version of my principles which you have 
 been at pains to make, is so elegant and finished as to 
 lead me to expect that the work will be more generally 
 read in French than in Latin, and better understood. 
 The only apprehension I entertain is lest the title 
 should deter some who have not been brought up to 
 letters, or with whom philosophy is in bad repute, be- 
 cause the kind they were taught has proved unsatisfac- 
 tory ; and this makes me think that it will be useful to 
 add a preface to it for the purpose of showing what the 
 matter of the work is, what end I had in view in writ- 
 ing it, and what utility may be derived from it. But 
 although it might be my part to write a preface of this 
 nature, seeing I ought to know those particulars better 
 than any other person, I cannot nevertheless prevail 
 upon myself to do anything more than merely to give 
 a summary of the chief points that fall, as I think, to be 
 discussed in it : and I leave it to your discretion to pre- 
 sent to the public such part of them as you shall judge 
 proper. 
 
 I should have desired, in the first place, to explain in 
 it what philosophy is, by commencing with the most 
 common matters, as, for example, that the word 
 107 
 
io8 LETTER OF THE AUTHOR. 
 
 philosophy signifies the study of wisdom, and that 
 by wisdom is to be understood not merely pru- 
 dence in the management of affairs, but a perfect 
 knowledge of all that man can know, as well for 
 the conduct of his life as for the preservation of his 
 health and the discovery of all the arts, and that knowl- 
 edge to subserve these ends must necessarily be de- 
 duced from first causes ; so that in order to study the 
 acquisition of it (which is properly called philosophiz- 
 ing), we must commence with the investigation of 
 those first causes which are called Principles. Now 
 these principles must possess two conditions: in the 
 first place, they must be so clear and evident that the 
 human mind, when it attentively considers them, cannot 
 doubt of their truth ; in the second place, the knowl- 
 edge of other things must be so dependent on them as 
 that though the principles themselves may indeed be 
 known apart from what depends on them, the latter 
 cannot nevertheless be known apart from the former. 
 It will accordingly be necessary thereafter to endeavour 
 so to deduce from those principles the knowledge of 
 the things that depend on them, as that there may be 
 nothing in the whole series of deductions which is not 
 perfectly manifest. God is in truth the only being who 
 is absolutely wise, that is, who possesses a perfect 
 knowledge of all things ; but we may say that men are 
 more or less wise as their knowledge of the most im- 
 portant truths is greater or less. And I am confident 
 that there is nothing, in what I have now said, in which 
 all the learned do not concur. 
 
 I should, in the next place, have proposed to con- 
 sider the utility of philosophy, and at the same time 
 have shown that, since it embraces all that the human 
 
LETTER OF THE AUTHOR. 109 
 
 mind can know, we ought to believe that it is by it we 
 are distinguished from savages and barbarians, and 
 that the civilisation and culture of a nation is regulated 
 by the degree in which true philosophy flourishes in it, 
 and, accordingly, that to contain true philosophers is 
 the highest privilege a state can enjoy. Besides this, 
 I should have shown that, as regards individuals, it is 
 not only useful for each man to have intercourse with 
 those who apply themselves to this study, but that it is 
 incomparably better he should himself direct his atten- 
 tion to it ; just as it is doubtless to be preferred that a 
 man should make use of his own eyes to direct his 
 steps, and enjoy by means of the same the beauties of 
 colour and light, than that he should blindly follow the 
 guidance of another ; though the latter course is cer- 
 tainly better than to have the eyes closed with no guide 
 except one's self. But to live without philosophizing 
 is in truth the same as keeping the eyes closed without 
 attempting to open them ; and the pleasure of seeing all 
 that sight discloses is not to be compared with the satis- 
 faction afforded by the discoveries of philosophy. And, 
 finally, this study is more imperatively requisite for the 
 regulation of our manners, and for conducting us 
 through life, than is the use of our eyes for directing 
 our steps. The brutes, which have only their bodies 
 to conserve, are continually occupied in seeking sources 
 of nourishment ; but men, of whom the chief part is 
 the mind, ought to make the search after wisdom their 
 principal care, for wisdom is the true nourishment of 
 the mind ; and I feel assured, moreover, that there are 
 very many who would not fail in the search, if they 
 would but hope for success in it, and knew the de- 
 gree of their capabilities for it. There is no mind, 
 
no LETTER OF THE AUTHOR. 
 
 how ignoble soever it be, which remains so firmly 
 bound up in the objects of the senses, as not some- 
 time or other to turn itself away from them in the 
 aspiration after some higher good, although not 
 knowing frequently wherein that good consists. The 
 greatest favourites of fortune — those who have health, 
 honours, and riches in abundance — are not more 
 exempt from aspirations of this nature than others ; nay, 
 I am persuaded that these are the persons who sigh the 
 most deeply after another good greater and more per- 
 fect still than any they already possess. But the supreme 
 good, considered by natural reason without the light of 
 faith, is nothing more than the knowledge of truth 
 through its first causes, in other words, the wisdom of 
 which philosophy is the study. And, as all these par- 
 ticulars are indisputably true, all that is required to 
 gain assent to their truth is that they be well stated. 
 
 But as one is restrained from assenting to these doc- 
 trines by experience, which shows that they who make 
 pretensions to philosophy are often less wise and rea- 
 sonable than others who never applied themselves to 
 the study, I should have here shortly explained where- 
 in consists all the science we now possess, and what are 
 the degrees of wisdom at which we have arrived. The 
 first degree contains only notions so clear of them- 
 selves that they can be acquired without meditation ; 
 the second comprehends all that the experience of the 
 senses dictates ; the third, that which the conversation 
 of other men teaches us ; to which may be added as the 
 fourth, the reading, not of all books, but especially of 
 such as have been written by persons capable of con- 
 veying proper instruction, for it is a species of conver- 
 sation we hold with their authors. And it seems to me 
 
LETTER OF THE AUTHOR. in 
 
 that all the wisdom we in ordinary possess is acquired 
 only in these four ways ; for I do not class divine reve- 
 lation among them, because it does not conduct us by 
 degrees, but elevates us at once to an infallible faith. 
 
 There have been, indeed, in all ages great minds who 
 endeavoured to find a fifth road to wisdom, incompar- 
 ably more sure and elevated than the other four. The 
 path they essayed was the search of first causes and 
 true principles, from which might be deduced the rea- 
 sons of all that can be known by man ; and it is to them 
 the appellation of philosophers has been more especially 
 accorded. I am not aware that there is any one of 
 them up to the present who has succeeded in this enter- 
 prise. The first and chief whose writings we possess, 
 are Plato and Aristotle, between whom there was no 
 difference, except that the former, following in the 
 footsteps of his master, Socrates, ingenuously con- 
 fessed that he had never yet been able to find anything 
 certain, and that he was contented to write what seemed 
 to him probable, imagining, for this end, certain prin- 
 ciples by which he endeavoured to account for the other 
 things. Aristotle, on the other hand, characterised by 
 less candour, although for twenty years the disciple of 
 Plato, and with no principles beyond those of his mas- 
 ter, completely reversed his mode of putting them, and 
 proposed as true and certain what it is probable he him- 
 self never esteemed as such. But these two men had 
 acquired much judgment and wisdom by the four pre- 
 ceding means, qualities which raised their authority 
 very high, so much so that those who succeeded them 
 were willing rather to acquiesce in their opinions, than 
 to seek better for themselves. The chief question 
 among their disciples, however, was as to whether we 
 
ii2 LETTER OF THE AUTHOR. 
 
 ought to doubt of all things or hold some as certain, — 
 a dispute which led them on both sides into extrava- 
 gant errors ; for a part of those who were for doubt, ex- 
 tended it even to the actions of life, to the neglect of the 
 most ordinary rules required for its conduct ; those, on 
 the other hand, who maintained the doctrine of cer- 
 tainty, supposing that it must depend upon the senses, 
 trusted entirely to them. To such an extent was this 
 carried by Epicurus, that it is said he ventured to af- 
 firm, contrary to all the reasonings of the astronomers, 
 that the sun is no larger than it appears. 
 
 It is a fault we may remark in most disputes, that, as 
 truth is the mean between the two opinions that are 
 upheld, each disputant departs from it in proportion to 
 the degree in which he possesses the spirit of contradic- 
 tion. But the error of those who leant too much to the 
 side of doubt, was not followed for any length of time, 
 and that of the opposite party has been to some extent 
 corrected by the doctrine that the senses are deceitful 
 in many instances. Nevertheless, I do not know that 
 this error was wholly removed by showing that certi- 
 tude is not in the senses, but in the understanding alone 
 when it has clear perceptions ; and that while we only 
 possess the knowledge which is acquired in the first 
 four grades of wisdom, we ought not to doubt of the 
 things that appear to be true in what regards the con- 
 duct of life, nor esteem them as so certain that we can- 
 not change our opinions regarding them, even though 
 constrained by the evidence of reason. 
 
 From ignorance of this truth, or, if there was any 
 one to whom it was known, from neglect of it, the ma- 
 jority of those who in these later ages aspired to be 
 philosophers, blindly followed Aristotle, so that they 
 
LETTER OF THE AUTHOR. 113 
 
 frequently corrupted the sense of his writings, and at- 
 tributed to him various opinions which he would not 
 recognise as his own were he now to return to the 
 world ; and those who did not follow him, among whom 
 are to be found many of the greatest minds, did yet not 
 escape being imbued with his opinions in their youth, 
 as these form the staple of instruction in the schools ; 
 and thus their minds were so preoccupied that they 
 could not rise to the knowledge of true principles. 
 And though I hold .all the philosophers in esteem, and 
 am unwilling to incur odium by my censure, I 
 can adduce a proof of my assertion, which I 
 do not think any of them will gainsay, which 
 is, that they all laid down as a principle what 
 they did not perfectly know. For example, I 
 know none of them who did not suppose that 
 there was gravity in terrestrial bodies ; but al- 
 though experience shows us very clearly that bodies 
 we call heavy descend towards the center of the 
 earth, we do not, therefore, know the nature of grav- 
 ity, that is, the cause or principle in virtue of which 
 bodies descend, and we must derive our knowledge of 
 it from some other source. The same may be said 
 of a vacuum and atoms, of heat and cold, of dryness 
 and humidity, and of salt, sulphur, and mercury, and 
 the other things of this sort which some have adopted 
 as their principles. But no conclusion deduced from 
 a principle which is not clear can be evident, even al- 
 though the deduction be formally valid ; and hence it 
 follows that no reasonings based on such principles 
 could lead them to the certain knowledge of any one 
 thing, nor consequently advance them one step in the 
 search after wisdom. And if they did discover any 
 
114 LETTER OF THE AUTHOR. 
 
 truth, this was due to one or other of the four 
 means above mentioned. Notwithstanding this, I am 
 in no degree desirous to lessen the honour which each 
 of them can justly claim ; I am only constrained to say, 
 for the consolation of those who have not given their 
 attention to study, that just as in travelling, when we 
 turn our back upon the place to which we were going, 
 we recede the farther from it in proportion as we pro- 
 ceed in the new direction for a greater length of time 
 and with greater speed, so that, though we may be af- 
 terwards brought back to the right way, we cannot 
 nevertheless arrive at the destined place as soon as if 
 we had not moved backwards at all ; so in philosophy, 
 when we make use of false principles, we depart the 
 farther from the knowledge of truth and wisdom ex- 
 actly in proportion to the care with which we cultivate 
 them, and apply ourselves to the deduction of diverse 
 consequences from them, thinking that we are philoso- 
 phizing well, while we are only departing the farther 
 from the truth ; from which it must be inferred that 
 they who have learned the least of all that has been 
 hitherto distinguished by the name of philosophy are 
 the most fitted for the apprehension of truth. 
 
 After making those matters clear, I should, in the 
 next place, have desired to set forth the grounds for 
 holding that the true principles by which we may reach 
 that highest degree of wisdom wherein consists the 
 sovereign good of human life, are those I have pro- 
 posed in this work ; and two considerations alone are 
 sufficient to establish this — the first of which is, that 
 these principles are very clear, and the second, that we 
 can deduce all other truths from them ; for it is only 
 these two conditions that are required in true princi- 
 
LETTER OF THE AUTHOR. 115 
 
 pies. But I easily prove that they are very clear; 
 firstly, by a reference to the manner in which I found 
 them, namely, by rejecting all propositions that were in 
 the least doubtful, for it is certain that such as could 
 not be rejected by this test when they were attentively 
 considered, are the most evident and clear which the 
 human mind can know. Thus by considering that he 
 who strives to doubt of all is unable nevertheless to 
 doubt that he is while he doubts, and that what reasons 
 thus, in not being able to doubt of itself and doubting 
 nevertheless of everything else, is not that which we 
 call our body, but what we name our mind or thought, 
 I have taken the existence of this thought for the first 
 principle, from which I very clearly deduced the fol- 
 lowing truths, namely, that there is a God who is the 
 author of all that is in the world, and who, being the 
 source of all truth, cannot have created our understand- 
 ing of such a nature as to be deceived in the judgments 
 it forms of the things of which it possesses a very clear 
 and distinct perception. Those are all the principles of 
 which I avail myself touching immaterial or metaphys- 
 ical objects, from which I most clearly deduce these 
 other principles of physical or corporeal things, 
 namely, that there are bodies extended in length, 
 breadth, and depth, which are of diverse figures and are 
 moved in a variety of ways. Such are in sum the 
 principles from which I deduce all other truths. The 
 second circumstance that proves the clearness of these 
 principles is, that they have been known in all ages, and 
 even received as true and indubitable by all men, with 
 the exception only of the existence of God, which has 
 been doubted by some, because they attributed too 
 
n6 LETTER OF THE AUTHOR. 
 
 much to the perceptions of the senses, and God can 
 neither be seen nor touched. 
 
 But, though all the truths which I class among my 
 principles were known at all times, and by all men, 
 nevertheless, there has been no one up to the pres- 
 ent, who, so far as I know, has adopted them as prin- 
 ciples of philosophy : in other words, as such that we 
 can deduce from them the knowledge of whatever else 
 is in the world. It accordingly now remains for me 
 to prove that they are such ; and it appears to me that I 
 cannot better establish this than by the test of experi- 
 ence : in other words, by inviting readers to peruse the 
 following work. For, though I have not treated in it 
 of all matters — that being impossible — I think I have 
 so explained all of which I had occasion to treat, that 
 they who read it attentively will have ground for the 
 persuasion that it is unnecessary to seek for any other 
 principles than those I have given, in order to arrive at 
 the most exalted knowledge of which the mind of man 
 is capable ; especially if, after the perusal of my writ- 
 ings, they take the trouble to consider how many di- 
 verse questions are therein discussed and explained, 
 and, referring to the writings of others, they see how 
 little probability there is in the reasons that are ad- 
 duced in explanation of the same questions by princi- 
 ples different from mine. And that they may the more 
 easily undertake this, I might have said that those im- 
 bued with my doctrines have much less difficulty in 
 comprehending the writings of others, and estimating 
 their true value, than those who have not been so im- 
 bued ; and this is precisely the opposite of what I before 
 said of such as commenced with the ancient philosophy, 
 
LETTER OF THE AUTHOR. 117 
 
 namely, that the more they have studied it the less fit 
 are they for rightly apprehending the truth. 
 
 I should also have added a word of advice regarding 
 the manner of reading this work, which is, that I 
 should wish the reader at first to go over the whole of 
 it, as he would a romance, without greatly straining 
 his attention, or tarrying at the difficulties he may per- 
 haps meet with in it, with the view simply of knowing 
 in general the matters of which I treat ; and that after- 
 wards, if they seem to him to merit a more careful ex- 
 amination, and he feel a desire to know their causes, he 
 may read it a second time, in order to observe the con- 
 nection of my reasonings ; but that he must not then 
 give it up in despair, although he may not everywhere 
 sufficiently discover the connection of the proof, or un- 
 derstand all the reasonings — it being only necessary to 
 mark with a pen the places where the difficulties occur, 
 and continue to read without interruption to the end; 
 then, if he does not grudge to take up the book a third 
 time, I am confident he will find in a fresh perusal the 
 solution of most of the difficulties he will have marked 
 before ; and that, if any still remain, their solution will 
 in the end be found in another reading. 
 
 I have observed, on examining the natural constitu- 
 tions of different minds, that there are hardly any so 
 dull or slow of understanding as to be incapable of ap- 
 prehending good opinions, or even of acquiring all the 
 highest sciences, if they be but conducted along the 
 right road. And this can also be proved by reason ; 
 for, as the principles are clear, and as nothing ought to 
 be deduced from them, unless most manifest inferences, 
 no one is so devoid of intelligence as to be unable to 
 comprehend the conclusions that flow from them. 
 
n8 LETTER OF THE AUTHOR. 
 
 But, besides the entanglement of prejudices, from 
 which no one is entirely exempt, although it is they 
 who have been the most ardent students of the false 
 sciences that receive the greatest detriment from 
 them, it happens very generally that people of ordin- 
 ary capacity neglect to study from a conviction that 
 they want ability, and that others, who are more ardent, 
 press on too rapidly : whence it comes to pass that they 
 frequently admit principles far from evident, and draw 
 doubtful inferences from them. For this reason, I 
 should wish to assure those who are too distrustful of 
 their own ability that there is nothing in my writings 
 which they may not entirely understand, if they only 
 take the trouble to examine them ; and I should wish, 
 at the same time, to warn those of an opposite tendency 
 that even the most superior minds will have need of 
 much time and attention to remark all I designed to 
 embrace therein. 
 
 After this, that I might lead men to understand the 
 real design I had in publishing them, I should have 
 wished here to explain the order which it seems to me 
 one ought to follow with the view of instructing him- 
 self. In the first place, a man who has merely the vul- 
 gar and imperfect knowledge which can be acquired 
 by the four means above explained, ought, before all 
 else, to endeavour to form for himself a code of morals 
 sufficient to regulate the actions of his life, as well for 
 the reason that this does not admit of delay as because 
 it ought to be our first care to live well. In the next 
 place, he ought to study Logic, not that of the schools, 
 for it is only, properly speaking, a dialectic which teaches 
 the mode of expounding to others what we already 
 know, or even of speaking much, without judgment, of 
 
LETTER OF THE AUTHOR. 119 
 
 what we do not know, by which means it corrupts 
 rather than increases good sense — but the logic which 
 teaches the right conduct of the reason with the view 
 of discovering the truths of which we are ignorant ; 
 and, because it greatly depends on usage, it is desirable 
 he should exercise himself for a length of time in prac- 
 tising its rules on easy and simple questions, as those 
 of the mathematics. Then, when he has acquired some 
 skill in discovering the truth in these questions, he 
 should commence to apply himself in earnest to true 
 philosophy, of which the first part is Metaphysics, con- 
 taining the principles of knowledge, among which is 
 the explication of the principal attributes of God, of the 
 immateriality of the soul, and of all the clear and sim- 
 ple notions that are in us ; the second is Physics, in 
 which, after finding the true principles of material 
 things, we examine, in general, how the whole universe 
 has been framed ; in the next place, we consider, in par- 
 ticular, the nature of the earth, and of all the bodies 
 that are most generally found upon it, as air, water, 
 fire, the loadstone and other minerals. In the next 
 place, it is necessary also to examine singly the nature of 
 plants, of animals/ and above all of man, in order that 
 we may thereafter be able to discover the other sciences 
 that are useful to us. Thus, all Philosophy is like a 
 tree, of which Metaphysics is the root, Physics the 
 trunk, and all the other sciences the branches that grow 
 out of this trunk, which are reduced to three principal, 
 namely, Medicine, Mechanics, and Ethics. By the 
 science of Morals, I understand the highest and most 
 perfect which, presupposing an entire knowledge of the 
 other sciences, is the last degree of wisdom. 
 
 But as it is not from the roots or the trunks of trees 
 
120 LETTER OF THE AUTHOR. 
 
 that we gather the fruit, but only from the extremities 
 of their branches, so the principal utility of philosophy 
 depends on the separate uses of its parts, which we can 
 only learn last of all. But, though I am ignorant of al- 
 most all these, the zeal I have always felt in endeavour- 
 ing to be of service to the public, was the reason why 
 I published, some ten or twelve years ago, certain Es- 
 says on the doctrines I thought I had acquired. The 
 first part of these Essays was a "Discourse on the 
 Method of rightly conducting the Reason, and seeking 
 Truth in the Sciences," in which I gave a summary of 
 the principal rules of logic, and also of an imperfect 
 ethic, which a person may follow provisionally so long 
 as he does not know any better. The other parts were 
 three treatises : the first of Dioptrics, the second of Me- 
 teors, and the third of Geometry. In the Dioptrics, I 
 designed to show that we might proceed far enough in 
 philosophy as to arrive, by its means, at the knowledge 
 of the arts that are useful to life, because the invention 
 of the telescope, of which I there gave an explanation, 
 is one of the most difficult that has ever been made. In 
 the treatise of Meteors, I desired to exhibit the differ- 
 ence that subsists between the philosophy I cultivate 
 and that taught in the schools, in which the same mat- 
 ters are usually discussed. In fine, in the Geometry, 
 I professed to demonstrate that I had discovered many 
 things that were before unknown, and thus afford 
 ground for believing that we may still discover many 
 others, with the view of thus stimulating all to the in- 
 vestigation of truth. Since that period, anticipating 
 the difficulty which many would experience in appre- 
 hending the foundations of the Metaphysics, I endeav- 
 oured to explain the chief points of them in a book of 
 
LETTER OF THE AUTHOR. 121 
 
 Meditations, which is not in itself large, but the size of 
 which has been increased, and the matter greatly illus- 
 trated, by the Objections which several very learned 
 persons sent to me on occasion of it, and by the Re- 
 plies which I made to them. At length, after it ap- 
 peared to me that those preceding treatises had suffi- 
 ciently prepared the minds of my readers for the 
 Principles of Philosophy, I also published it ; and I 
 have divided this work into four parts, the first of 
 which contains the principles of human knowledge, and 
 which may be called the First Philosophy, or Meta- 
 physics. That this part, accordingly, may be properly 
 understood, it will be necessary to read beforehand the 
 book of Meditations I wrote on the same subject. The 
 other three parts contain all that is most general in 
 Physics, namely, the explication of the first laws or 
 principles of nature, and the way in which the heavens, 
 the fixed stars, the planets, comets, and generally the 
 whole universe, were composed ; in the next place, the 
 explication, in particular, of the nature of this earth, 
 the air, water, fire, the magnet, which are the bodies 
 we most commonly find everywhere around it, and of 
 all the qualities we observe in these bodies, as light, 
 heat, gravity, and the like. In this way, it seems to 
 me, I have commenced the orderly explanation of the 
 whole of philosophy, without omitting any of the mat- 
 ters that ought to precede the last which I discussed. 
 But to bring this undertaking to its conclusion, I 
 ought hereafter to explain, in the same manner, the na- 
 ture of the other more particular bodies that are on the 
 earth, namely, minerals, plants, animals, and especially 
 man ; finally, to treat thereafter with accuracy of Medi- 
 cine, Ethics, and Mechanics. I should require to do 
 
122 LETTER OF THE AUTHOR. 
 
 this in order to give to the world a complete body of 
 philosophy ; and I do not yet feel myself so old, — I do 
 not so much distrust my strength, nor do I find myself 
 so far removed from the knowledge of what remains, 
 as that I should not dare to undertake to complete this 
 design, provided I were in a position to make all the 
 experiments which I should require for the basis and 
 verification of my reasonings. But seeing that would 
 demand a great expenditure, to which the resources 
 of a private individual like myself would not be 
 adequate, unless aided by the public, and as I have no 
 ground to expect this aid, I believe that I ought for the 
 future to content myself with studying for my own in- 
 struction, and posterity will excuse me* if I fail hereaf- 
 ter to labour for them. 
 
 Meanwhile, that it may be seen wherein I think I 
 have already promoted the general good, I will here 
 mention the fruits that may be gathered from my Prin- 
 ciples. The first is the satisfaction which the mind 
 will experience on finding in the work many truths be- 
 fore unknown ; for although frequently truth does not 
 so greatly affect our imagination as falsity and fiction, 
 because it seems less wonderful and is more simple, yet 
 the gratification it affords is always more durable and 
 solid. The second fruit is, that in studying these prin- 
 ciples we will become accustomed by degrees to judge 
 better of all the things we come in contact with, and 
 thus be made wiser, in which respect the effect will be 
 quite the opposite of the common philosophy, for we 
 may easily remark in those we call pedants that it ren- 
 ders them less capable of rightly exercising their rea- 
 son than they would have been if they had never known 
 it. The third is, that the truths which they contain, 
 
LETTER OF THE AUTHOR. 123 
 
 being highly clear and certain, will take away all 
 ground of dispute, and thus dispose men's minds to 
 gentleness and concord ; whereas the contrary is the ef- 
 fect of the controversies of the schools, which, as they 
 insensibly render those who are exercised in them more 
 wrangling and opinionative, are perhaps the prime 
 cause of the heresies and dissensions that now harass 
 the world. The last and chief fruit of these Principles 
 is, that one will be able, by cultivating them, to dis- 
 cover many truths I myself have not unfolded, and 
 thus passing by degrees from one to another, to 
 acquire in course of time a perfect knowledge of 
 the whole of philosophy, and to rise to the highest 
 degree of wisdom. For just as all the arts, though in 
 their beginnings they are rude and imperfect, are yet 
 gradually perfected by practice, from their containing 
 at first something true, and whose effect experience 
 evinces ; so in philosophy, when we have true principles, 
 we cannot fail by following them to meet sometimes 
 with other truths ; and we could not better prove the 
 falsity of those of Aristotle, than by saying that men 
 made no progress in knowledge by their means during 
 the many ages they prosecuted them. 
 
 I well know that there are some men so precipitate 
 and accustomed to use so little circumspection in what 
 they do, that, even with the most solid foundations, 
 they could not rear a firm superstructure ; and as it is 
 usually those who are the readiest to make books, they 
 would in a short time mar all that I have done, and in- 
 troduce uncertainty and doubt into my manner of phil- 
 osophizing, from which I have carefully endeavoured 
 to banish them, if people were to receive their writings 
 as mine, or as representing my opinions. I had, not 
 
124 LETTER OF THE AUTHOR. 
 
 long ago, some experience of this in one of those who 
 were believed desirous of following me the most 
 closely,* and one too of whom I had somewhere said 
 that I had such confidence in his genius as to believe 
 that he adhered to no opinions which I should not be 
 ready to avow as mine ; for he last year published a 
 book entitled "Fundamenta Physicse," in which, al- 
 though he seems to have written nothing on the sub- 
 ject of Physics and Medicine which he did not take 
 from my writings, as well from those I have published 
 as from another still imperfect on the nature of ani- 
 mals, which fell into his hands ; nevertheless, because 
 he has copied them badly, and changed the order, and 
 denied certain metaphysical truths upon which all 
 Physics ought to be based, I am obliged wholly to dis- 
 avow his work, and here to request readers not to at- 
 tribute to me any opinion unless they find it expressly 
 stated in my own writings, and to receive no opinion as 
 true, whether in my writings or elsewhere, unless they 
 see that it is very clearly deduced from true principles. 
 I well know, likewise, that many ages may elapse ere 
 all the truths deducible from these principles are 
 evolved out of them, as well because the greater num- 
 ber of such as remain to be discovered depend on cer- 
 tain particular experiments that never occur by chance, 
 but which require to be investigated with care and ex- 
 pense by men of the highest intelligence, as because it 
 will hardly happen that the same persons who have the 
 sagacity to make a right use of them, will possess also 
 the means of making them, and also because the ma- 
 jority of the best minds have formed so low an estimate 
 
 * Regius; see La Vie de M. Descartes, réduite en abrégé 
 (Baillet). Liv. vii., chap. vii. — T. 
 
LETTER OF THE AUTHOR. 125 
 
 of philosophy in general, from the imperfections they 
 have remarked in the kind in vogue up to the present 
 time, that they cannot apply themselves to the search 
 after truth. 
 
 But, in conclusion, if the difference discernible be- 
 tween the principles in question and those of every 
 other system, and the great array of truths deducible 
 from them, lead them to discern the importance of con- 
 tinuing the search after these truths, and to observe the 
 degree of wisdom, the perfection and felicity of life, to 
 which they are fitted to conduct us, I venture to believe 
 that there will not be found one who is not ready to la- 
 bour hard in so profitable a study, or at least to favour 
 and aid with all his might those who shall devote them- 
 selves to it with success. 
 
 The height of my wishes is, that posterity may some- 
 time behold the happy issue of it, etc. 
 
TO THE MOST SERENE PRINCESS, 
 
 ELIZABETH, 
 
 ELDEST DAUGHTER OF FREDERICK, KING OF BOHEMIA, 
 
 COUNT PALATINE, AND ELECTOR OF THE 
 
 SACRED ROMAN EMPIRE. 
 
 Madam, — The greatest advantage I have derived from 
 the writings which I have already published, has arisen 
 from my having, through means of them, become 
 known to your Highness, and thus been privileged to 
 hold occasional converse with one in whom so many 
 rare and estimable qualities are united, as to lead me 
 to believe I should do service to the public by proposing 
 them as an example to posterity. It would ill become 
 me to flatter, or to give expression to anything of 
 which I had no certain knowledge, especially in the 
 first pages of a work in which I aim at laying down the 
 principles of truth. And the generous modesty that is 
 conspicuous in all your actions, assures me that the 
 frank and simple judgment of a man who only writes 
 what he believes will be more agreeable to you than the 
 ornate laudations of those who have studied the art of 
 compliment. For this reason, I will give insertion to 
 nothing in this letter for which I have not the certainty 
 both of experience and reason ; and in the exordium, as 
 in the rest of the work, I will write only as becomes 
 a philosopher. There is a vast difference between real 
 and apparent virtues ; and there is also a great discrep- 
 ancy between those real virtues that proceed from an 
 126 
 
DEDICATION. 127 
 
 accurate knowledge of the truth, and such as are accom- 
 panied with ignorance or error. The virtues I call appar- 
 ent are only, properly speaking, vices, which, as they are 
 less frequent than the vices that are opposed to them, 
 and are farther removed from them than the inter- 
 mediate virtues, are usually held in higher esteem than 
 those virtues. Thus, because those who fear dangers 
 too much are more numerous than they who fear them 
 too little, temerity is frequently opposed to the vice of 
 timidity, and taken for a virtue, and is commonly more 
 highly esteemed than true fortitude. Thus, also, the 
 prodigal are in ordinary more praised than the liberal ; 
 and none more easily acquire a great reputation for 
 piety than the superstitious and hypocritical. With re- 
 gard to true virtues, these do not all proceed from true 
 knowledge, for there are some that likewise spring 
 from defect or error ; thus, simplicity is frequently the 
 source of goodness, fear of devotion, and despair of 
 courage. The virtues that are thus accompanied with 
 some imperfections differ from each other, and have 
 received diverse appellations. But those pure and per- 
 fect virtues that arise from the knowledge of good 
 alone are all of the same nature, and may be comprised 
 under the single term wisdom. For, whoever owns the 
 firm and constant resolution of always using his reason 
 as well as lies in his power, and in all his actions of do- 
 ing what he judges to be best, is truly wise, as far 
 as his nature permits ; and by this alone he is just, 
 courageous, temperate, and possesses all the other vir- 
 tues, but so well balanced as that none of them appears 
 more prominent than another : and for this reason, al- 
 though they are much more perfect than the virtues 
 that blaze forth through the mixture of some defect, 
 
128 DEDICATION. 
 
 yet, because the crowd thus observes them less, they 
 are not usually extolled so highly. Besides, of the two 
 things that are requisite for the wisdom thus described, 
 namely, the perception of the understanding and the 
 disposition of the will, it is only that which lies in the 
 will which all men can possess equally, inasmuch as the 
 understanding of some is inferior to that of others. 
 But although those who have only an inferior under- 
 standing may be as perfectly wise as their nature per- 
 mits, and may render themselves highly acceptable to 
 God by their virtue, provided they preserve always a 
 firm and constant resolution to do all that they shall 
 judge to be right, and to omit nothing that may lead 
 them to the knowledge of the duties of which they are 
 ignorant; nevertheless, those who preserve a constant 
 resolution of performing the right, and are especially 
 careful in instructing themselves, and who possess also 
 a highly perspicacious intellect, arrive doubtless at a 
 higher degree of wisdom than others ; and I see that 
 these three particulars are found in great perfection in 
 your Highness. P'or, in the first place, your desire of 
 self-instruction is manifest, from the circumstance that 
 neither the amusements of the court, nor the accus- 
 tomed mode of educating ladies, which ordinarily 
 condemns them to ignorance, have been sufficient to 
 prevent you from studying with much care all that 
 is best in the arts and sciences ; and the incomparable 
 perspicacity of your intellect is evinced by this, that 
 you penetrated the secrets of the sciences and acquired 
 an accurate knowledge of them in a very short period. 
 But of the vigour of your intellect I have a still 
 stronger proof, and one peculiar to myself, N in that I 
 have never yet met any one who understood so gener- 
 
DEDICATION. 129 
 
 ally and so well as yourself all that is contained in my 
 writings. For there are several, even among men of 
 the highest intellect and learning, who find them very 
 obscure. And I remark, in almost all those who are 
 versant in Metaphysics, that they are wholly dis- 
 inclined from Geometry ; and, on the other hand, that 
 the cultivators of Geometry have no ability for the in- 
 vestigations of the First Philosophy : insomuch that I 
 can ^av with truth I know but^one mind, and th at is 
 your own, to which both studies are alike congenial, 
 and which I therefore, with propriety, designate in- 
 comparable. But what most of all enhances my ad- 
 miration is, that so accurate and varied an acquaintance 
 with the whole circle of the sciences is not found in 
 some aged doctor who has employed many years in 
 contemplation, but in a Princess still young, and whose 
 countenance and years would more fitly represent one 
 of the Graces than a Muse or the sage Minerva. In 
 conclusion, I not only remark in your Highness all that 
 is requisite on the part of the mind to perfect and sub- 
 lime wisdom, but also all that can be required on the 
 part of the will or the manners, in which benignity and 
 gentleness are so conjoined with majesty that, though 
 fortune has attacked you with continued injustice, it 
 has failed either to irritate or crush you. And this 
 constrains me to such veneration that I not only think 
 this work due to you, since it treats of philosophy 
 which is the study of wisdom, but likewise feel not 
 more zeal for my reputation as a philosopher than 
 pleasure in subscribing myself, — 
 
 Of your most Serene Highness, 
 The most devoted servant, 
 
 DESCARTES. 
 
THE PRINCIPLES OF PHILOSOPHY, 
 
 PART I. 
 
 OF THE PRINCIPLES OF HUMAN KNOWLEDGE. 
 
 I. Th^ax jii orcjer to s^ek ^ tr u th . Jt is ne cesjp.rvjQt^gJn 
 
 the course of our life, to doubt as far as possible, of all 
 
 As we were at one time children, and as we formed 
 various judgments regarding the objects presented to 
 our senses, when as yet we had not the entire use of 
 our reason, numerous prejudices stand in the way of 
 our arriving at the knowledge of truth ; and of these it 
 seems impossible for us to rid ourselves, unless we un- 
 dertake, once in our lifetime, to doubt of all those 
 things in which we may discover even the smallest sus- 
 picion of uncertainty. 
 
 II. That we ought also to consider as false all that 
 is doubtful. 
 
 Moreover, it will be useful likewise to esteem as false 
 the things of which we shall be able to doubt, that we 
 may with greater clearness discover what possesses 
 most certainty and is the easiest to know. 
 
 III. That we ought not meanwhile-tn make use of 
 doubt in the conduct of life. 
 
 In the meantime, it is to be observed that we are to 
 avail ourselves of this general doubt only while en- 
 gaged in the contemplation of truth. For, as far as 
 concerns the conduct of life, we are very frequently 
 130 
 
PART I. 131 
 
 obliged to follow opinions merely probable, or even 
 sometimes, though of two courses of action we may 
 not perceive more probability in the one than in the 
 other, to choose one or other, seeing the opportunity of 
 acting would not unfrequently pass away before we 
 could free ourselves from our doubts. 
 
 IV. Why we may doubt^ of ^ensibjf ^'hingp.. 
 
 Accordingly, since we now only design to apply our- 
 selves to the investigation of truth, we will doubt, first, 
 whether of all the things that have ever fallen under 
 our senses, or which we have ever imagined, any one 
 really exist ; in the first place, because we know by ex- 
 perience that the senses sometimes err, and it would be 
 imprudent to trust too much to what has even once de- 
 ceived us ; secondly, because in dreams we perpetually 
 seem to perceive or imagine innumerable objects which 
 have no existence. And to one who has thus resolved 
 upon a general doubt, there appear no marks by which 
 he can with certainty distinguish sleep from the waking 
 state. 
 
 V. Why—we may also doubt of mat hematic al dem-^ 
 onstrat iqnfi . 
 
 We will also doubt of the other things we have before 
 held as most certain, even of the demonstrations of 
 mathematics, and of their principles which we have 
 hitherto deemed selfrevident ; in the first place, because 
 we have sometimes seen men fall into error in such 
 matters, and admit as absolutely certain and self evi- 
 dent what to us appeared false, but chiefly because we 
 have learnt that God who created us is all-powerful ; 
 for we do not yet know whether perhaps it was his will 
 to create us so that we are always deceived, even in the 
 things we think we know best : since this does not ap- 
 
132 THE PRINCIPLES OF PHILOSOPHY. 
 
 pear more impossible than our being occasionally de- 
 ceived, which, however, as observation teaches us, is 
 the case. And if we suppose that an all-powerful God 
 is not the author of our being, and that we exist of our- 
 selves or by some other means, still, the less powerful 
 we suppose our author to be, the greater reason will we 
 have for believing that we are not so perfect .as that we 
 may not be continually deceived. 
 
 VI. That we possess a free-will, by which we can 
 withhold our assent from what is doubtful, and thu§ 
 avoid error. „ 
 
 But meanwhile, whoever in the end may be the au- 
 thor of our being, and however powerful and deceitful 
 he may be, we are nevertheless conscious of a freedom, 
 by which we can refrain from admitting to a place in 
 our belief aught that is not manifestly certain and un- 
 doubted, and thus guard against ever being deceived. 
 
 VII. That we cannot doubt of our existence while 
 we doubt, and that this is the first knowledge we ac- 
 quire when we philosophize in order. 
 
 While we thus reject all of which we can entertain 
 the smallest doubt, and even imagine that, it is false, 
 we easily indeed suppose that there is neither God, nor 
 sky, nor bodies, and that we ourselves even have 
 neither hands nor feet, nor, finally, a body ; but we can- 
 not in the same way suppose that we are not while we 
 doubt of the truth of these things ; for there is a re- 
 pugnance in conceiving that what thinks does not exist 
 at the very time when it thinks. Accordingly, the 
 knowledge, / think, therefore I am, is the first and 
 most certain that occurs to one who philosophizes 
 orderly. 
 
 VIII. That we hence discover the distinction be- 
 
PART I. 133 
 
 tween the mind and the body, or between a thinking 
 and corporeal thing. 
 
 And this is the best mode of discovering the nature 
 of the mind, and its distinctness from the body: for 
 examining what we are, while supposing, as we now 
 do, that there is nothing really existing apart from our 
 thought, we clearly perceive that neither extension, nor 
 figure, nor local motion,* nor anything similar that can 
 be attributed to body, pertains to our nature, and noth- 
 ing save thought alone ; and, consequently, that the 
 notion we have of our mind precedes that of any cor- 
 poreal thing, and is more certain, seeing we still doubt 
 whether there is any body in existence, while we al- 
 ready perceive that we think. 
 
 IX. What thought (cogitatio) is. 
 
 By the word thought, I understand all that which so 
 takes place in us that we of ourselves are immediately 
 conscious of it ; and, accordingly, not only to under- 
 stand (intelligere, entendre), to will (velle), to im- 
 agine (imaginari) , but even to perceive (sentir e, sen- 
 tir), are here the same as to think (cogitare, penser). 
 For if I say, I see, or, I walk, therefore I am ; and if I 
 understand by vision or walking the act of my eyes or 
 of my limbs, which is the work of the body, the con- 
 clusion is not absolutely certain, because, as is often 
 the case in dreams, I may think that I see or walk, al- 
 though I do not open my eyes or move from my place, 
 and even, perhaps, although I have no body: but, if I 
 mean the sensation itself, or consciousness of seeing or 
 walking, the knowledge is manifestly certain, because 
 
 * Instead of "local motion," the French has "existence in 
 any place." 
 
134 THE PRINCIPLES OF PHILOSOPHY. 
 
 it is then referred to the mind, which alone perceives 
 or is conscious that it sees or walks.* 
 
 X. That the notions which are simplest and self- 
 evident, are obscured by logical définitions ; and that 
 such are not to be reckoned among the cognitions ac- 
 quired by study, [but as born with us] . 
 
 I do not here explain several other terms which I 
 have used, or design to use in the sequel, because their 
 meaning seems to me sufficiently self-evident. And I 
 frequently remarked that philosophers erred in at- 
 tempting to explain, by logical definitions, such truths 
 as are most simple and self-evident ; for they thus only 
 rendered them more obscure. And when I said that 
 the proposition, I think, therefore I am, is of all others 
 the first and most certain which occurs to one philoso- 
 phizing orderly, I did not therefore deny that it was 
 necessary to know what thought, existence, and certi- 
 tude are, and the truth that, in order to think it is nec- 
 essary to be, and the like ; but, because these are the 
 most simple notions, and such as of themselves afford 
 the knowledge of nothing existing, I did not judge it 
 proper there to enumerate them. 
 
 XL How we can know our mind more clearly than 
 our body. 
 
 But now that it may be discerned how the knowl- 
 edge we have of the mind not only precedes, and has 
 greater certainty, but is even clearer, than that we 
 have of the body, it must be remarked, as a matter 
 that is highly manifest by the natural light, that to 
 nothing no affections or qualities belong; and, accord- 
 ingly, that where we observe certain affections, there 
 
 * In the French, "which alone has the power of perceiving, 
 or of being conscious in any other way whatever." 
 
PART I. 135 
 
 a thing or substance to which these pertain, is neces- 
 sarily found. The same light also shows us that we 
 know a thing or substance more clearly in proportion 
 as we discover in it a greater number of qualities. 
 Now, it is manifest that we remark a greater number 
 of qualities in our mind than in any other thing; for 
 there is no occasion on which we know anything what- 
 ever when we are not at the same time led with much 
 greater certainty to the knowledge of our own mind. 
 For example, if I judge that there is an earth because 
 I touch or see it, on the same ground, and with still 
 greater reason, I must be persuaded that my mind 
 exists ; for it may be, perhaps, that I think I touch the 
 earth while there is one in existence ; but it is not pos- 
 sible that I should so judge, and my mind which thus 
 judges not exist ; and the same holds good of whatever 
 object is presented to our mind. 
 
 XII. How it happens that every one does not come 
 equally to know this. 
 
 Those who have not philosophized in order have had 
 other opinions on this subject, because they never dis- 
 tinguished with sufficient care the mind from the body. 
 For, although they had no difficulty in believing that 
 they themselves existed, and that they had a higher 
 assurance of this than of any other thing, nevertheless, 
 as they did not observe that by themselves, they ought 
 here to understand their minds alone [when the ques- 
 tion related to metaphysical certainty] ; and since, on 
 the contrary, they rather meant their bodies which 
 they saw with their eyes, touched with their hands, 
 and to which they erroneously attributed the faculty 
 of perception, they were prevented from distinctly ap- 
 prehending the nature of the mind. 
 
136 THE PRINCIPLES OF PHILOSOPHY. 
 
 XIII. In what sense the knowledge of other things 
 depends upon the knowledge of God. 
 
 But when the mind, which thus knows itself but is 
 still in doubt as to all other things, looks around on 
 all sides, with a view to the farther extension of its 
 knowledge, it first of all discovers within itself the 
 ideas of many things ; and while it simply contem- 
 plates them, and neither affirms nor denies that there 
 is anything beyond itself corresponding to them, it is 
 in no danger of erring. The mind also discovers cer- 
 tain common notions out of which it frames various 
 demonstrations that carry conviction to such a degree 
 as to render doubt of their truth impossible, so long as 
 we give attention to them. For example, the mind 
 has within itself ideas of numbers and figures, and it 
 has likewise among its common notions the principle 
 that if equals be added to equals the wholes will be 
 equal, and the like ; from which it is easy to demon- 
 strate that the three angles of a triangle are equal to 
 two right angles, etc. Now, so long as we attend to 
 the premises from which this conclusion and others 
 similar to it were deduced, we feel assured of their 
 truth; but, as the mind cannot always think of these 
 with attention, when it has the remembrance of a con- 
 clusion without recollecting the order of its deduction, 
 and is uncertain whether the author of its being has 
 created it of a nature that is liable to be deceived, even 
 in what appears most evident, it perceives that there is 
 just ground to distrust the truth of such conclusions, 
 and that it cannot possess any certain knowledge until 
 it has discovered its author. 
 
 XIV. That we may validly infer the existence of 
 
PART I. 137 
 
 God from necessary existence being comprised in the 
 concept we have of him. 
 
 When the mind afterwards reviews the different 
 ideas that are in it, it discovers what is by far the chief 
 among them — that of a Being omniscient, all-power- 
 ful, and absolutely perfect ; and it observes that in this 
 idea there is contained not only possible and contin- 
 gent existence, as in the ideas of all other things which 
 it clearly perceives, but existence absolutely necessary 
 and eternal. And just as because, for example, the 
 equality of its three angles to two right angles is neces- 
 sarily comprised in the idea of a triangle, the mind is 
 firmly persuaded that the three angles of a triangle 
 are equal to two right angles ; so, from its perceiving 
 necessary and eternal existence to be comprised in the 
 idea which it has of an all-perfect Being, it ought 
 manifestly to conclude that this all-perfect Being 
 exists. 
 
 XV. That necessary existence is not in the same 
 way comprised in the notions which we have of other 
 things, but merely contingent existence. 
 
 The mind will be still more certain of the truth of 
 this conclusion, if it consider that it has no idea of any 
 other thing in which it can discover that necessary ex- 
 istence is contained ; for, from this circumstance alone, 
 it will discern that the idea of an all-perfect Being has 
 not been framed by itself, and that it does not repre- 
 sent a chimera, but a true and immutable nature, which 
 must exist since it can only be conceived as necessarily 
 existing. 
 
 XVI. That prejudices hinder many from clearly 
 knowing the necessity of the existence of God. 
 
 Our mind would have no difficulty in assenting to 
 
138 THE PRINCIPLES OF PHILOSOPHY. 
 
 this truth, if it were, first of all, wholly free from pre- 
 judices; but as we have been accustomed to distin- 
 guish, in all other things, essence from existence, and 
 to imagine at will many ideas of things which neither 
 are nor have been, it easily happens, when we do not 
 steadily fix our thoughts on the contemplation of the 
 all-perfect Being, that a doubt arises as to whether the 
 idea we have of him is not one of those which we 
 frame at pleasure, or at least of that class to whose 
 essence existence does not pertain. 
 
 XVII. That the greater objective (representative) 
 perfection there is in our idea of a thing, the greater 
 also must be the perfection of its cause. 
 
 When we further reflect on the various ideas that' 
 are in us, it is easy to perceive that there is not much 
 difference among them, when we consider them sim- 
 ply as certain modes of thinking, but that they are 
 widely different, considered in reference to the objects 
 they represent ; and that their causes must be so much 
 the more perfect according to the degree of objective 
 perfection contained in them.* For there is no differ- 
 ence between this and the case of a person who has the 
 idea of a machine, in the construction of which great 
 skill is displayed, in which circumstances we have a 
 right to inquire how he came by this idea, whether, for 
 example, he somewhere saw such a machine con- 
 structed by another, or whether he was so accurately 
 taught the mechanical sciences, or is endowed with 
 such force of genius, that he was able of himself to in- 
 vent it, without having elsewhere seen anything like 
 it ; for all the ingenuity which is contained in the idea 
 
 * "as what they represent of their object has more perfection." 
 — French. 
 
PART I. 139 
 
 objectively only, or as it were in a picture, must exist 
 at least in its first and chief cause, whatever that may 
 be, not only objectively or representatively, but in 
 truth formally or eminently. 
 
 XVIII. That the existence of God may be again 
 inferred from the above. 
 
 Thus, because we discover in our minds the idea of 
 God, or of an all-perfect Being, we have a right to in- 
 quire into the source whence we derive it ; and we will 
 discover that the perfections it represents are so im- 
 mense as to render it quite certain that we could only 
 derive it from an all-perfect Being; that is, from a 
 God really existing. For it is not only manifest by 
 the natural light that nothing cannot be the cause of 
 anything whatever, and that the more perfect cannot 
 arise from the less perfect, so as to be thereby pro- 
 duced as by its efficient and total cause, but also that 
 it is impossible we can have the idea or representation 
 of anything whatever, unless there be somewhere, 
 either in us or out of us, an original which comprises, 
 in reality, all the perfections that are thus represented 
 to us ; but, as we do not in any way find in ourselves 
 those absolute perfections of which we have the idea, 
 we must conclude that they exist in some nature dif- 
 ferent from ours, that is, in God, or at least that they 
 were once in him ; and it most manifestly follows [from 
 their infinity] that they are still there. 
 
 XIX. That, although we may not comprehend the 
 nature of God, there is yet nothing which we know so 
 clearly as his perfections. 
 
 This will appear sufficiently certain and manifest to 
 those who have been accustomed to contemplate the 
 idea of God, and to turn their thoughts to his infinite 
 
140 THE PRINCIPLES OF PHILOSOPHY. 
 
 perfections ; for, although we may not comprehend 
 them, because it is of the nature of the infinite not to 
 be comprehended by what is finite, we nevertheless 
 conceive them more clearly and distinctly than mate- 
 rial objects, for this reason, that, being simple, and un- 
 obscured by limits,* they occupy our mind more fully. 
 
 XX. That we are not the cause of ourselves, but 
 that this is God, and consequently that there is a God. 
 
 But, because every one has not observed this, and 
 because, when we have an idea of any machine in 
 which great skill is displayed, we usually know with 
 sufficient accuracy the manner in which we obtained 
 it, and as we cannot even recollect when the idea we 
 have of a God was communicated to us by him, seeing 
 it was always in our minds, it is still necessary that we 
 should continue our review, and make inquiry after 
 our author, possessing, as we do, the idea of the in- 
 finite perfections of a God : for it is in the highest de- 
 gree evident by the natural light, that that which knows 
 something more perfect than itself, is not the source 
 of its own being, since it would thus have given to it- 
 self all the perfections which it knows ; and that, con- 
 sequently, it could draw its origin from no other being 
 than from him who possesses in himself all those per- 
 fections, that is, from God. 
 
 XXI. That the duration alone of our life is suffi- 
 cient to demonstrate the existence of God. 
 
 * After limits, "what of them we do conceive is much less 
 confused. There is, besides, no speculation more calculated 
 to aid in perfecting our understanding, and which is more 
 important than this, inasmuch as the consideration of an ob- 
 ject that has no limits to its perfections fills us with satisfac- 
 tion and assurance." — French. 
 
PART I. 141 
 
 The truth of this demonstration will clearly appear, 
 provided we consider the nature of time, or the dura- 
 tion of things ; for this is of such a kind that its parts 
 are not mutually dependent, and never co-existent ; 
 and, accordingly, from the fact that we now are, it 
 does not necessarily follow that we shall be a moment 
 afterwards, unless some cause, viz., that which first 
 produced us, shall, as it were, continually reproduce 
 us, that is, conserve us. For we easily understand 
 that there is no power in us by which we can conserve 
 ourselves, and that the being who has so much power 
 as to conserve us out of himself, must also by so much 
 the greater reason conserve himself, or rather stand 
 in need of being conserved by no one whatever, and, in 
 fine, be God. 
 
 XXII. That in knowing the existence of God, in 
 the manner here explained, we likewise know all his 
 attributes, as far as they can be known by the natural 
 light alone. 
 
 There is the great advantage in proving the exist- 
 ence of God in this way, viz., by his idea, that we at 
 the same time know what he is, as far as the weakness 
 of our nature allows; for, reflecting on the idea we 
 have of him which is born with us, we perceive that he 
 is eternal, omniscient, omnipotent, the source of all 
 goodness and truth, creator of all things, and that, in 
 fine, he has in himself all that in which we can clearly 
 discover any infinite perfection or good that is not 
 limited by any imperfection. 
 
 XXIII. That God is not corporeal, and does not 
 perceive by means of senses as we do, or will the evil 
 of sin. 
 
 For there are indeed many things in the world that 
 
142 THE PRINCIPLES OF PHILOSOPHY. 
 
 are to a certain extent imperfect or limited, though 
 possessing also some perfection; and it is accordingly 
 impossible that any such can be in God. Thus, look- 
 ing to corporeal nature,* since divisibility is included 
 in local extension, and this indicates imperfection, it is 
 certain that God is not body. And although in men it 
 is to some degree a perfection to be capable of perceiv- 
 ing by means of the senses, nevertheless since in every 
 sense there is passivityf which indicates dependency, 
 we must conclude that God is in no manner possessed 
 of senses, and that he only understands and wills, not, 
 'however, like us, by acts in any way distinct, but al- 
 ways by an act that is one, identical, and the simplest 
 possible, understands,wills, and operates all, that is, all 
 things that in reality exist; for he does not will the 
 evil of sin, seeing this is but the negation of being. 
 
 XXIV. That in passing from the knowledge of 
 God to the knowledge of the creatures, it is necessary 
 to remember that our understanding is finite, and the 
 power of God infinite. 
 
 But as we know that God alone is the true cause of 
 all that is or can be, we will doubtless follow the best 
 way of philosophizing, if, from the knowledge we 
 have of God himself, we pass to the explication of the 
 things which he has created, and essay to deduce it 
 from the notions that are naturally in our minds, for 
 we will thus obtain the most perfect science, that is, 
 the knowledge of effects through their causes. But 
 
 * In the French, "since extension constitutes the nature of 
 body." 
 
 t In the French, "because our perceptions arise from im- 
 pressions made upon us from another source," i. e., than our- 
 selves. 
 
PART I. 143 
 
 that we may be able to make this attempt with suf- 
 ficient security from error, we must use the precaution 
 to bear in mind as much as possible that God, who is 
 the author of things, is infinite, while we are wholly 
 finite. 
 
 XXV. That we must believe all that God has re- 
 vealed, although it may surpass the reach of our 
 faculties. 
 
 Thus, if perhaps God reveal to us or others, matters 
 concerning himself which surpass the natural powers 
 of our mind, such as the mysteries of the incarnation 
 and of the trinity, we will not refuse to believe them, 
 although we may not clearly understand them; nor 
 will we be in any way surprised to find in the immens- 
 ity of his nature, or even in what he has created, many 
 things that exceed our comprehension. 
 
 XXVI. That it is not needful to enter into dis- 
 putes* regarding the infinite, but merely to hold all that 
 in which we can find no limits as indefinite, such as the 
 extension of the world, the divisibility of the parts of 
 matter, the number of the stars, etc. 
 
 We will thus never embarrass ourselves by disputes 
 about the infinite, seeing it would be absurd for us who 
 are finite to undertake to determine anything regarding 
 it, and thus as it were to limit it by endeavouring to 
 comprehend it. We will accordingly give ourselves 
 no concern to reply to those who demand whether the 
 half of an infinite line is also infinite, and whether an 
 infinite number is even or odd, and the like, because 
 it is only such as imagine their minds to be infinite who 
 seem bound to entertain questions of this sort. And, 
 for our part, looking to all those things in which in cer- 
 * "to essay to comprehend the infinite." — French. 
 
144 THE PRINCIPLES OF PHILOSOPHY. 
 
 tain senses, we discover no limits, we will not, there- 
 fore, affirm that they are infinite, but will regard them 
 simply as indefinite. Thus, because we cannot imagine 
 extension so great that we cannot still conceive greater, 
 we will say that the magnitude of possible things is 
 indefinite, and because a body cannot be divided into 
 parts so small that each of these may not be conceived 
 as again divided into others still smaller, let us regard 
 quantity as divisible into parts whose number is in- 
 definite ; and as we cannot imagine so many stars that 
 it would seem impossible for God to create more, let 
 us suppose that their number is indefinite, and so in 
 other instances. 
 
 XXVII. What difference there is between the in- 
 definite and the infinite. 
 
 And we will call those things indefinite rather than 
 infinite, with the view of reserving to God alone the 
 appellation of infinite ; in the first place, because not 
 only do we discover in him alone no limits on any side, 
 but also because we positively conceive that he admits 
 of none ; and in the second place, because we do not in 
 the same way positively conceive that other things are 
 in every part unlimited, but merely negatively admit 
 that their limits, if they have any, cannot be discovered 
 by us. 
 
 XXVIII. That we must examine, not the final, but 
 the efficient, causes of created things. 
 
 Likewise, finally, we will not seek reasons of natural 
 things from the end which God or nature proposed to 
 himself in their creation (i. e., final causes),* for we 
 
 * " We will not stop to consider the ends which God pro- 
 posed to himself in the creation of the world, and we will en- 
 tirely reject from our philosophy the search of final causes." — 
 French. 
 
PART I. 145 
 
 ought not to presume so far as to think that we are 
 sharers in the counsels of Deity, but, considering him 
 as the efficient cause of all things, let us endeavour to 
 discover by the natural light* which he has planted in 
 us, applied to those of his attributes of which he has 
 been willing we should have some knowledge, what 
 must be concluded regarding those effects we perceive 
 by our senses ; bearing in mind, however, what has been 
 already said, that we must only confide in this natural 
 light so long as nothing contrary to its dictates is re- 
 vealed by God himself.f 
 
 XXIX. That God is not the cause of our errors. 
 The first attribute of God which here falls to be 
 
 considered, is that he is absolutely veracious and the 
 source of all light, so that it is plainly repugnant for 
 him to deceive us, or to be properly and positively the 
 cause of the errors to which we are consciously sub- 
 ject ; for although the address to deceive seems to be 
 some mark of subtlety of mind among men, yet with- 
 out doubt the will to deceive only proceeds from malice 
 or from fear and weakness, and consequently cannot 
 be attributed to God. 
 
 XXX. That consequently all which we clearly per- 
 ceive is true, and that we are thus delivered from the 
 doubts above proposed. 
 
 Whence it follows, that the light of nature, or 
 faculty of knowledge given us by God, can never com- 
 pass any object which is not true, in as far as it attains 
 to a knowledge of it, that is, in as far as the object is 
 clearly and distinctly apprehended. For God would 
 
 * " Faculty of reasoning." — French. 
 
 t The last clause, beginning "bearing in mind," is omitted 
 in the French. 
 
146 THE PRINCIPLES OF PHILOSOPHY. 
 
 have merited the appellation of a deceiver if he had 
 given us this faculty perverted, and such as might lead 
 us to take falsity for truth [when we used it aright]. 
 Thus the highest doubt is removed, which arose from 
 our ignorance on the point as to whether perhaps our 
 nature was such that we might be deceived even in 
 those things that appear to us the most evident. The 
 same principle ought also to be of avail against all the 
 other grounds of doubting that have been already 
 enumerated. For mathematical truths ought now to 
 be above suspicion, since these are of the clearest. 
 And if we perceive anything by our senses, whether 
 while awake or asleep, we will easily discover the truth 
 provided we separate what there is of clear and dis- 
 tinct in the knowledge from what is obscure and con- 
 fused. There is no need that I should here say more 
 on this subject, since it has already received ample 
 treatment in the metaphysical Meditations; and what 
 follows will serve to explain it still more accurately. 
 
 XXXI. That our errors are, in respect of God, 
 merely negations, but, in respect of ourselves, priva- 
 tions. 
 
 But as it happens that we frequently fall into error, 
 although God is no deceiver, if we desire to inquire 
 into the origin and cause of our errors, with a view to 
 guard against them, it is necessary to observe that they 
 depend less on our understanding than on our will, 
 and that they have no need of the actual concourse of 
 God, in order to their production; so that, when con- 
 sidered in reference to God, they are merely negations, 
 but in reference to ourselves, privations. 
 
 XXXII. That there are only two modes of think- 
 
PART I. 147 
 
 ing in us, viz., the perception of the understanding and 
 the action of the will. 
 
 For all the modes of thinking of which we are con- 
 scious may be referred to two general classes, the one 
 of which is the perception or operation of the under- 
 standing, and the other the volition or operation of the 
 will. Thus, to perceive by the senses (sentire), to 
 imagine, and to conceive things purely intelligible, 8 
 are only different modes of perceiving (percipiendi) ; 
 but to desire, to be averse from, to affirm, to deny, to 
 doubt, are different modes of willing. 
 
 XXXIII. That we never err unless when we judge 
 of something which we do not sufficiently apprehend. 
 
 When we apprehend anything we are in no danger 
 of error, if we refrain from judging of it in any way; 
 and even when we have formed a judgment regarding 
 it, we would never fall into error, provided we gave 
 our assent only to what we clearly and distinctly per- 
 ceived ; but the reason why we are usually deceived, is 
 that we judge without possessing an exact knowledge 
 of that of which we judge. 
 
 XXXIV. That the will as well as the understand- 
 ing is required for judging. 
 
 I admit that the understanding is necessary for 
 judging, there being no room to suppose that we can 
 judge of that which we in no way apprehend; but the 
 will also is required in order to our assenting to what 
 we have in any degree perceived. It is not necessary, 
 however, at least to form any judgment whatever, that 
 we have an entire and perfect apprehension of a thing ; 
 for we may assent to many things of which we have 
 only a very obscure and confused knowledge. 
 
 XXXV. That the will is of greater extension than 
 
148 THE PRINCIPLES OF PHILOSOPHY. 
 
 the understanding, and is thus the source of our 
 errors. 
 
 Further, the perception of the intellect extends only 
 to the few things that are presented to it, and is always 
 very limited : the will, on the other hand, may, in a cer- 
 tain sense, be said to be infinite, because we observe 
 nothing that can be the object of the will of any other, 
 even of the unlimited will of God, to which ours can- 
 not also extend, so that we easily carry it beyond the 
 objects we clearly perceive ; and when we do this, it is 
 not wonderful that we happen to be deceived. 
 
 XXXVI. That our errors cannot be imputed to 
 God. 
 
 But although God has not given us an omniscient 
 understanding, he is not on this account to be con- 
 sidered in any wise the author of our errors, for it is 
 of the nature of created intellect to be finite, and of 
 finite intellect not to embrace all things. 
 
 XXXVII. That the chief perfection of man is his 
 being able to act freely or by will, and that it is this 
 which renders him worthy of praise or blame. 
 
 That the will should be the more extensive is in har- 
 mony with its nature ; and it is a high perfection in 
 man to be able to act by means of it, that is, freely.; 
 and thus in a peculiar way to be the master of his own 
 actions, and merit praise or blame. For self-acting 
 machines are not commended because they perform 
 with exactness all the movements for which they were 
 adapted, seeing their motions are carried on neces- 
 sarily ; but the maker of them is praised on account of 
 the exactness with which they were framed, because he 
 did not act of necessity, but freely ; and, on the same 
 principle, we must attribute to ourselves something 
 
PART I. 149 
 
 more on this account, that when we embrace truth, we 
 do so not of necessity, but freely. 
 
 XXXVIII. That error is a defect in our mode of 
 acting, not in our nature ; and that the faults of their 
 subjects may be frequently attributed to other masters, 
 but never to God. 
 
 It is true, that as often as we err, there is some de- 
 fect in our mode of action or in the use of our liberty, 
 but not in our nature, because this is always the same, 
 whether our judgments be true or false. And al- 
 though God could have given to us such perspicacity 
 of intellect that we should never have erred, we have, 
 notwithstanding, no right to demand this of him ; for, 
 although with us he who was able to prevent evil and 
 did not is held guilty of it, God is not in the same way 
 to be reckoned responsible for our errors because he 
 had the power to prevent them, inasmuch as the do- 
 minion which some men possess over others has been 
 instituted for the purpose of enabling them to hinder 
 those under them from doing evil, whereas the do- 
 minion which God exercises over the universe is per- 
 fectly absolute and free. For this reason we ought to 
 thank him for the goods he has given us, and not com- 
 plain that he has not blessed us with all which we know 
 it was in his power to impart. 
 
 XXXIX. That the liberty of our will is self-evi- 
 dent. 
 
 Finally, it is so manifest that we possess a free will, 
 capable of giving or withholding its assent, that this 
 truth must be reckoned among the first and most com- 
 mon notions which are born with us. This, indeed, 
 has already very clearly appeared, for when essaying 
 to doubt of all things, we went so far as to suppose 
 
150 THE PRINCIPLES OF PHILOSOPHY. 
 
 even that he who created us employed his limitless 
 power in deceiving us in every way, we were conscious 
 nevertheless of being free to abstain from believing 
 what was not in every respect certain and undoubted. 
 But that of which we are unable to doubt at such a time 
 is as self-evident and clear as any thing we can ever 
 know^ 
 
 XL. That it is likewise certain that God has fore- 
 ordained all things. 
 
 But because what we have already discovered of 
 God, gives us the assurance that his power is so im- 
 mense that we would sin in thinking ourselves capable 
 of ever doing anything which he had not ordained be- 
 forehand, we should soon be embarrassed in great 
 difficulties if we undertook to harmonise the pré-or- 
 dination of God with the freedom of our will, and en- 
 deavoured to comprehend both truths at once. 
 
 XLI. How the freedom of our will may be recon- 
 ciled with the Divine pre-ordination. 
 
 But, in place of this, we will be free from these em- 
 barrassments if we recollect that our mind is limited, 
 while the power of God, by which he not only knew 
 from all eternity what is or can be, but also willed and 
 pre-ordained it, is infinite. It thus happens that we 
 possess sufficient intelligence to know clearly and dis- 
 tinctly that this power is in God, but not enough to 
 comprehend how he leaves the free actions of men in- 
 determinate ; and, on the other hand, we have such con- 
 sciousness of the liberty and indifference which exists 
 in ourselves, that there is nothing we more clearly or 
 perfectly comprehend: [so that the omnipotence of 
 God ought not to keep us from believing it]. For it 
 would be absurd to doubt of that of which we are fully 
 
PART I. 151 
 
 conscious, and which we experience as existing in our- 
 selves, because we do not comprehend another matter 
 which, from its very nature, we know to be incompre- 
 hensible. 
 
 XLII. How, although we never will to err, it is 
 nevertheless by our will that we do err. 
 
 But now since we know that all our errors depend 
 upon our will, and as no one wishes to deceive himself, 
 it may seem wonderful that there is any error in our 
 judgments at all. It is necessary to remark, however, 
 that there is a great difference between willing to be 
 deceived, and willing to yield assent to opinions in 
 which it happens that error is found. For though 
 there is no one who expressly wishes to fall into error, 
 we will yet hardly find any one who is not ready to as- 
 sent to things in which, unknown to himself, error 
 lurks ; and it even frequently happens that it is the de- 
 sire itself of following after truth that leads those not 
 fully aware of the order in which it ought to be sought 
 for, to pass judgment on matters of which they have 
 no adequate knowledge, and thus to fall into error. 
 
 XLIII. That we shall never err if we give our as- 
 sent only to what we clearly and distinctly perceive. 
 
 But it is certain we will never admit falsity for 
 truth, so long as we judge only of that which we 
 clearly and distinctly perceive; because, as God is no 
 deceiver, the faculty of knowledge which he has given 
 us cannot be fallacious, nor, for the same reason, the 
 faculty of will, when we do not extend it beyond the 
 objects we clearly know. And even although this 
 truth could not be established by reasoning, the minds 
 of all have been so impressed by nature as spontan- 
 
152 THE PRINCIPLES OF PHILOSOPHY. 
 
 eously to assent to whatever is clearly perceived, and 
 to experience an impossibility to doubt of its truth. 
 
 XLIV. That we uniformly judge improperly when 
 we assent to what we do not clearly perceive, although 
 our judgment may chance to be true ; and that it is 
 frequently our memory which deceives us by leading 
 us to believe that certain things were formerly suffi- 
 ciently understood by us. 
 
 It is likewise certain that, when we approve of any 
 reason which we do not apprehend, we are either de- 
 ceived, or, if we stumble on the truth, it is only by 
 chance, and thus we can never possess the assurance 
 that we are not in error. I confess it seldom happens 
 that we judge of a thing when we have observed we 
 do not apprehend it, because it is a dictate of the 
 natural light never to judge of what we do not know. 
 But we most frequently err in this, that we presume 
 upon a past knowledge of much to which we give our 
 assent, as to something treasured up in the memory, 
 and perfectly known to us ; whereas, in truth, we have 
 no such knowledge. 
 
 XLV. What constitutes clear and distinct percep- 
 tion. 
 
 There are indeed a great many persons who, through 
 their whole lifetime, never perceive anything in a way 
 necessary for judging of it properly; for the knowl- 
 edge upon which we can establish a certain and in- 
 dubitable judgment must be not only clear, but also 
 distinct. I call that clear which is present and mani- 
 fest to the mind giving attention to it, just as we are 
 said clearly to see objects when, being present to the 
 eye looking on, they stimulate it with sufficient force, 
 
PART I. 153 
 
 and it is disposed to regard them; but the distinct is 
 that which is so precise and different from all other ob- 
 jects as to comprehend in itself only what is clear.* 
 
 XLVI. It is shown, from the example of pain, that 
 a perception may be clear without being distinct, but 
 that it cannot be distinct unless it is clear. 
 
 For example, when any one feels intense pain, the 
 knowledge which he has of this pain is very clear, but 
 it is not always distinct; for men usually confound it 
 with the obscure judgment they form regarding its 
 nature, and think that there is in the suffering part 
 something similar to the sensation of pain of which 
 they are' alone conscious. And thus perception may 
 be clear without being distinct, but it can never be dis- 
 tinct without likewise being clear. 
 
 XLVII. That, to correct the prejudices of our early 
 years, we must consider what is clear in each of our 
 simplet notions. 
 
 And, indeed, in our early years, the mind was so im- 
 mersed in the body, that, although it perceived many 
 things with sufficient clearness, it yet knew nothing 
 distinctly; and since even at that time we exercised 
 our judgment in many matters, numerous prejudices 
 were thus contracted, which, by the majority, are never 
 afterwards laid aside. But that we may now be in a 
 position to get rid of these, I will here briefly enum- 
 erate all the simple notions of which our thoughts are 
 composed, and distinguish in each what is clear from 
 what is obscure, or fitted to lead into error. 
 
 XLVIII. That all the objects of our knowledge are 
 
 * "what appears manifestly to him who considers it as he 
 ought." — French. 
 t "first." — French. 
 
154 THE PRINCIPLES OF PHILOSOPHY. 
 
 to be regarded either (i) as things or the affections 
 of things: or (2) as eternal truths; with the enumera- 
 tion of things. 
 
 Whatever objects fall under our knowledge we con- 
 sider either as things or the affections of things,* or as 
 eternal truths possessing no existence beyond our 
 thought. Of the first class the most general are sub- 
 stance, duration, order, number, and perhaps also some 
 others, which notions apply to all the kinds of things. 
 I do not, however, recognise more than two highest 
 kinds (summa genera) of things; the first of intellec- 
 tual things, or such as have the power of thinking, in- 
 cluding mind or thinking substance and its properties ; 
 the second, of material things, embracing extended 
 substance, or body and its properties. Perception, 
 volition, and all modes as well of knowing as of will- 
 ing, are related to thinking substance ; on the other 
 hand, to extended substance we refer magnitude, or ex- 
 tension in length, breadth, and depth, figure, motion, 
 situation, divisibility of parts themselves, and the like. 
 There are, however, besides these, certain things of 
 which we have an internal experience that ought not 
 to be referred either to the mind of itself, or to the body 
 alone, but to the close and intimate union between 
 them, as will hereafter be shown in its place. Of this 
 class are the appetites of hunger and thirst, etc., and 
 also the emotions or passions of the mind which are 
 not exclusively mental affections, as the emotions of 
 anger, joy, sadness, love, etc. ; and, finally, all the sen- 
 
 * Things and the affections of things are (in the French) 
 equivalent to "what has some (1. e. a real) existence," as op- 
 posed to the class of "eternal truths," which have merely an 
 ideal existence. 
 
PART I. 155 
 
 sations, as of pain, titillation, light and colours, sounds, 
 smells, tastes, heat, hardness, and the other tactile 
 qualities. 
 
 XLIX. That the eternal truths cannot be thus 
 enumerated, but that this is not necessary. 
 
 What I have already enumerated we are to regard 
 as things, or the qualities or modes of things. We 
 now come to speak of eternal truths. When we ap- 
 prehend that it is impossible a thing can arise from 
 nothing, this proposition, ex nihilo nihil fit, is not con- 
 sidered as somewhat existing, or as the mode of a 
 thing, but as an eternal truth having its seat in our 
 mind, and is called a common notion or axiom. Of 
 this class are the following : — It is impossible the same 
 thing can at once be and not be; what is done cannot 
 be undone ; he who thinks must exist while he thinks ; 
 and innumerable others, the whole of which it is in- 
 deed difficult to enumerate, but this is not necessary, 
 since, if blinded by no prejudices, we cannot fail to 
 know them when the occasion of thinking them occurs. 
 
 L. That these truths are clearly perceived, but not 
 equally by all men, on account of prejudices. 
 
 And, indeed, with regard to these common notions, 
 it is not to be doubted that they can be clearly and dis- 
 tinctly known, for otherwise they would not merit this 
 appellation : as, in truth, some of them are not, with re- 
 spect to all men, equally deserving of the name, because 
 they are not equally admitted by all : not, however, 
 from this reason, as I think, that the faculty of knowl- 
 edge of one man extends farther than that of another, 
 but rather because these common notions are opposed 
 to the prejudices of some, who, on this account, are not 
 able readily to embrace them, even although others, 
 
156 THE PRINCIPLES OF PHILOSOPHY. 
 
 who are free from those prejudices, apprehend them 
 with the greatest clearness. 
 
 LI. What substance is, and that the term is not ap- 
 plicable to God and the creatures in the same sense. 
 
 But with regard to what we consider as things or 
 the modes of things, it is worth while to examine each 
 of them by itself. By substance we can conceive noth- 
 ing else than a thing which exists in such a way as to 
 stand in need of nothing beyond itself in order to its 
 existence. And, in truth, there can be conceived but 
 one substance which is absolutely independent, and that 
 is God. We perceive that all other things can exist 
 only by help of the concourse of God. And, accord- 
 ingly, the term substance does not apply to God and 
 the creatures univocally, to adopt a term familiar in 
 the schools ; that is, no signification of this word can 
 be distinctly understood which is common to God and 
 them. 
 
 LII. That the term is applicable univocally to the 
 mind and the body, and how substance itself is known. 
 
 Created substances, however, whether corporeal or 
 thinking, may be conceived under this common con- 
 cept ; for these are things which, in order to their exist- 
 ence, stand in need of nothing but the concourse of 
 God. But yet substance cannot be first discovered 
 merely from its being a thing which exists independ- 
 ently, for existence by itself is not observed by us. 
 We easily, however, discover substance itself from any 
 attribute of it, by this common notion, that of nothing 
 there are no attributes, properties, or qualities: for, 
 from perceiving that some attribute is present, we infer 
 that some existing thing or substance to which it may 
 be attributed is also of necessity present. 
 
PART I. 157 
 
 LUI. That of every substance there is one princi- 
 pal attribute, as thinking of the mind, extension of the 
 body. 
 
 But, although any attribute is sufficient to lead us to 
 the knowledge of substance, there is, however, one 
 principal property of every substance, which constitutes 
 its nature or essence, and upon which all the others de- 
 pend. Thus, extension in length, breadth, and depth, 
 constitutes the nature of corporeal substance; and 
 thought the nature of thinking substance. For every 
 other thing that can be attributed to body, presupposes 
 extension, and is only some mode of an extended 
 thing ; as all the properties we discover in the mind are 
 only diverse modes of thinking. Thus, for example, 
 we cannot conceive figure unless in something ex- 
 tended, nor motion unless in extended space, nor imagi- 
 nation, sensation, or will, unless in a thinking thing. 
 But, on the other hand, we can conceive extension 
 without figure or motion, and thought without imagi- 
 nation or sensation, and so of the others ; as is clear to 
 any one who attends to these matters. 
 
 LIV. How we may have clear and distinct notions 
 of the substance which thinks, of that which is cor- 
 poreal, and of God. 
 
 And thus we may easily have two clear and distinct 
 notions or ideas, the one of created substance, which 
 thinks, the other of corporeal substance, provided we 
 carefully distinguish all the attributes of thought from 
 those of extension. We may also have a clear and 
 distinct idea of an uncreated and independent thinking 
 substance, that is, of God, provided we do not suppose 
 that this idea adequately represents to us all that is in 
 God, and do not mix up with it anything fictitious, but 
 
158 THE PRINCIPLES OF PHILOSOPHY. 
 
 attend simply to the characters that are comprised in 
 the notion we have of him, and which we clearly know 
 to belong to the nature of an absolutely perfect Being. 
 For no one can deny that there is in us such an idea of 
 God, without groundlessly supposing that there is no 
 knowledge of God at all in the human mind. 
 
 LV. How duration, order, and number may be also 
 distinctly conceived. 
 
 We will also have most distinct conceptions of dura- 
 tion, order, and number, if, in place of mixing up with 
 our notions of them that which properly belongs to the 
 concept of substance, we merely think that the duration 
 of a thing is a mode under which we conceive this 
 thing, in so far as it continues to exist; and, in like 
 manner, that order and number are not in reality dif- 
 ferent from things disposed in order and numbered, 
 but only modes under which we diversely consider 
 these things. 
 
 LVI. What are modes, qualities, attributes. 
 
 And, indeed, we here understand by modes the same 
 with what we elsewhere designate attributes or quali- 
 ties. But when we consider substance as affected or 
 varied by them, we use the term modes ; when from 
 this variation it may be denominated of such a kind, 
 we adopt the term qualities [to designate the different 
 modes which cause it to be so named] ; and, finally, 
 when we simply regard these modes as in the substance, 
 we call them attributes. Accordingly, since God must 
 be conceived as superior to change, it is not proper to 
 say that there are modes or qualities in him, but sim- 
 ply attributes ; and even in created things that which is 
 found in them always in the same mode, as existence 
 
PART I. 159 
 
 and duration in the thing which exists and endures, 
 ought to be called attribute and not mode or quality. 
 
 LVII. That some attributes exist in the things to 
 which they are attributed, and others only in our 
 thought ; and what duration and time are. 
 
 Of these attributes or modes there are some which 
 exist in the things themselves, and others that have 
 only an existence in our thought ; thus, for example, 
 time, which we distinguish from duration taken in its 
 generality, and call the measure of motion, is only a 
 certain mode under which we think duration itself, for 
 we do not indeed conceive the duration of things that 
 are moved to be different from the duration of things 
 that are not moved : as is evident from this, that if two 
 bodies are in motion for an hour, the one moving 
 quickly and the other slowly, we do not reckon more 
 time in the one than in the other, although there may 
 be much more motion in the one of the bodies than in 
 the other. But that we may comprehend the duration 
 of all things under a common measure, we compare 
 their duration with that of the greatest and most regu- 
 lar motions that give rise to years and days, and which 
 we call time ; hence what is so designated is nothing 
 superadded to duration, taken in its generality, but a 
 mode of thinking. 
 
 LVIII. That number and all universals are only 
 modes of thought. 
 
 In the same way number, when it is not considered 
 as in created things, but merely in the abstract or in 
 general, is only a mode of thinking; and the same is 
 true of all those general ideas we call universals. 
 
 LIX. How universals are formed ; and what are the 
 
i6o THE PRINCIPLES OF PHILOSOPHY. 
 
 five common, viz., genus, species, difference, property, 
 and accident. 
 
 Universals arise merely from our making use of one 
 and the same idea in thinking of all individual objects 
 between which there subsists a certain likeness ; and 
 when we comprehend all the objects represented by 
 this idea under one name, this term likewise becomes 
 universal. For example, when we see two stones, and 
 do not regard their nature farther than to remark that 
 there are two of them, we form the idea of a certain 
 number, which we call the binary ; and when we after- 
 wards see two birds or two trees, and merely take no- 
 tice of them so far as to observe that there are two of 
 them, we again take up the same idea as before, which 
 is, accordingly, universal ; and we likewise give to this 
 number the same universal appellation of binary. In 
 the same way, when we consider a figure of three sides, 
 we form a certain idea, which we call the idea of a 
 triangle, and we afterwards make use of it as the uni- 
 versal to represent to our mind all other figures of three 
 sides. But when we remark more particularly that of 
 figures of three sides, some have a right angle and 
 others not, we form the universal idea of a right-an- 
 gled triangle, which being related to the preceding as 
 more general, may be called species ; and the right an- 
 gle the universal difference by which right-angled 
 triangles are distinguished from all others ; and farther, 
 because the square of the side which sustains the right 
 angle is equal to the squares of the other two sides, and 
 because this property belongs only to this species of 
 triangles, we may call it the universal property of the 
 species. Finally, if we suppose that of these triangles 
 some are moved and others not, this will be their uni- 
 
PART I. 161 
 
 versai accident ; and, accordingly, we commonly reckon 
 five universals, viz., genus, species, difference, prop- 
 erty, accident. 
 
 LX. Of distinctions ; and first of the real. 
 
 But number in things themselves arises from the 
 distinction there is between them: and distinction is 
 threefold, viz., real, modal, and of reason. The real 
 properly subsists between two or more substances ; and 
 it is sufficient to assure us that two substances are 
 really mutually distinct, if only we are able clearly and 
 distinctly to conceive the one of them without the other. 
 For the knowledge we have of God renders it certain 
 that he can effect all that of which we have a distinct 
 idea: wherefore, since we have now, for example, the 
 idea of an extended and corporeal substance, though 
 we as yet do not know with certainty whether any sucK 
 thing is really existent, nevertheless, merely because 
 we have the idea of it, we may be assured that such 
 may exist ; and, if it really exists, that every part which 
 we can determine by thought must be really distinct 
 from the other parts of the same substance. In the 
 same way, since every one is conscious that he thinks, 
 and that he in thought can exclude from himself every 
 other substance, whether thinking or extended, it is 
 certain that each of us thus considered is really dis- 
 tinct from every other thinking and corporeal sub- 
 stance. And although we suppose that God united a 
 body to a soul so closely that it was impossible to form 
 a more intimate union, and thus made a composite 
 whole, the two substances would remain really distinct, 
 notwithstanding this union ; for with whatever tie God 
 connected them, he was not able to rid himself of the 
 power he possessed of separating them, or of conserv- 
 
i62 THE PRINCIPLES OF PHILOSOPHY. 
 
 ing the one apart from the other, and the things which 
 God can separate or conserve separately are really dis- 
 tinct. 
 
 LXI. Oi the modal distinction. 
 
 There are two kinds of modal distinctions, viz., that 
 between the mode properly so-called and the substance 
 of which it is a mode, and that between two modes of 
 the same substance. Of the former we have an exam- 
 ple in this, that we can clearly apprehend substance 
 apart from the mode which we say differs from it; 
 while, on the other hand, we cannot conceive this mode 
 without conceiving the substance itself. There is, for 
 example, a modal distinction between figure or motion 
 and corporeal substance in which both exist; there is 
 a similar distinction between affirmation or recollection 
 and the mind. Of the latter kind we have an illustra- 
 tion in our ability to recognise the one of. two modes 
 apart from the other, as figure apart from motion, and 
 motion apart from figure ; though we cannot think of 
 either the one or the other without thinking of the 
 common substance in which they adhere. If, for ex- 
 ample, a stone is moved, and is withal square, we can, 
 indeed, conceive its square figure without its motion, 
 and reciprocally its motion without its square figure ; 
 but we can conceive neither this motion nor this figure 
 apart from the substance of the stone. As for the dis- 
 tinction according to which the mode of one substance 
 is different from another substance, or from the mode 
 of another substance, as the motion of one body is dif- 
 ferent from another body or from the mind, or as mo- 
 tion is different from doubt, it seems to me that it 
 should be called real rather than modal, because these 
 modes cannot be clearly conceived apart from the 
 
PART I. 163 
 
 really distinct substances of which they are the modes. 
 
 LXII. Of the distinction of reason (logical dis- 
 tinction). 
 
 Finally, the distinction of reason is that between a 
 substance and some one of its attributes, without which 
 it is impossible, however, we can have a distinct con- 
 ception of the substance itself; or between two such 
 attributes of a common substance, the one of which we 
 essay to think without the other. This distinction is 
 manifest from our inability to form a clear and dis- 
 tinct idea of such substance, if we separate from it 
 such attribute ; or to have a clear perception of the one 
 of two such attributes if we separate it from the other. 
 For example, because any substance which ceases to 
 endure ceases also to exist, duration is not distinct 
 from substance except in thought (ratione) ; and in 
 general all the modes of thinking which we consider 
 as in objects differ only in thought, as well from the 
 objects of which they are thought as from each other 
 in a common object.* It occurs, indeed, to me that I 
 have elsewhere classed this kind of distinction with the 
 modal (viz., towards the end of the Reply to the First 
 Objections to the Meditations on the First Philoso- 
 phy) ; but there it was only necessary to treat of these 
 distinctions generally, and it was sufficient for my pur- 
 pose at that time simply to distinguish both of them 
 from the real. 
 
 LXIII. How thought and extension may be dis- 
 
 * "and generally all the attributes that lead us to entertain 
 different thoughts of the same thing, such as, for example, 
 the extension of body and its property of divisibility, do not 
 differ from the body which is to us the object of them, or from 
 each other, unless as we sometimes confusedly think the one 
 without thinking the other. — French. 
 
IÔ4 THE PRINCIPLES OF PHILOSOPHY. 
 
 tinctly known, as constituting, the one the nature of 
 mind, the other that of body. 
 
 Thought and extension may be regarded as consti- 
 tuting the natures of intelligent and corporeal sub- 
 stance ; and then they must not be otherwise conceived 
 than as the thinking and extended substances them- 
 selves, that is, as mind and body, which in this way are 
 conceived with the greatest clearness and distinctness. 
 Moreover, we more easily conceive extended or think- 
 ing substance than substance by itself, or with the 
 omission of its thinking or extension. For there is 
 some difficulty in abstracting the notion of substance 
 from the notions of thinking and extension, which, in 
 truth, are only diverse in thought itself ~(l e., logically 
 different) ; and a concept is not more distinct because 
 it comprehends fewer properties, but because we ac- 
 curately distinguish what is comprehended in it from 
 all other notions. 
 
 LXIV. How these may likewise be distinctly con- 
 ceived as modes of substance. 
 
 Thought and extension may be also considered as 
 modes of substance ; in as far, namely, as the same 
 mind may have many different thoughts, and the same 
 body, with its size unchanged, may be extended in sev- 
 eral diverse ways, at one time more in length and less 
 in breadth or depth, and at another time more in 
 breadth and less in length ; and then they are modally 
 distinguished from substance, and can be conceived not 
 less clearly and distinctly, provided they be not re- 
 garded as substances or things separated from others, 
 but simply as modes of things. For by regarding 
 them as in the substances of which they are the modes, 
 we distinguish them from these substances, and take 
 
PART I. 165 
 
 them for what in truth they are : whereas, on the other 
 hand, if we wish to consider them apart from the sub- 
 stances in which they are, we should by this itself re- 
 gard them as self -subsisting things, and thus confound 
 the ideas of mode and substance. 
 
 LXV. How we may likewise know their modes. 
 
 In the same way we will best apprehend the diverse 
 modes of thought, as intellection, imagination, recol- 
 lection, volition, etc., and also the diverse modes of ex- 
 tension, or those that belong to extension, as all figures, 
 the situation of parts and their motions, provided we 
 consider them simply as modes of the things in which 
 they are ; and motion as far as it is concerned, pro- 
 vided we think merely of locomotion, without seeking 
 to know the force that produces it, and which never- 
 theless I will essay to explain in its own place. 
 
 LXVI. How our sensations, affections, and appe- 
 tites may be clearly known, although we are frequently 
 wrong in our judgments regarding them. 
 
 There remain our sensations, affections, and appe- 
 tites, of which we may also have a clear knowledge, if 
 we take care to comprehend in the judgments we form 
 of them only that which is precisely contained in our 
 perception of them, and of which we are immediately 
 conscious. There is, however, great difficulty in ob- 
 serving this, at least in respect of sensations ; because 
 we have all, without exception, from our youth judged 
 that all the things we perceived by our senses had an 
 existence beyond our thought, and that they were en- 
 tirely similar to the sensations, that is, perceptions, we 
 had of them. Thus when, for example, we saw a cer- 
 tain colour, we thought we saw something occupying 
 a place out of us, and which was entirely similar to 
 
i66 THE PRINCIPLES OF PHILOSOPHY. 
 
 that idea of colour we were then conscious of; and 
 from the habit of judging in this way, we seemed to 
 see this so clearly and distinctly that we esteemed it 
 (i, e., the externality of the colour) certain and in- 
 dubitable. 
 
 LXVII. That we are frequently deceived in our 
 judgments regarding pain itself. 
 
 The same prejudice has place in all our other sensa- 
 tions, even in those of titillation and pain. For though 
 we are not in the habit of believing that there exist out 
 of us objects that resemble titillation and pain, we do 
 not nevertheless consider these sensations as in the 
 mind alone, or in our perception, but as in the hand, 
 or foot, or some other part of our body. There is no 
 reason, however, to constrain us to believe that the 
 pain, for example, which we feel, as it were, in the 
 foot is something out of the mind existing in the foot, 
 or that the light which we see, as it were, in the sun. 
 exists in the sun as it is in us. Both these beliefs are 
 prejudices of our early years, as will clearly appear in 
 the sequel. 
 
 LXVIII. How in these things what we clearly con- 
 ceive is to be distinguished from that in which we may 
 be deceived. 
 
 But that we may distinguish what is clear in our sen- 
 sations from what is obscure, we ought most carefully 
 to observe that we possess a clear and distinct knowl- 
 edge of pain, colour, and other things of this sort, 
 when we consider them simply as sensations or 
 thoughts; but that, when they are judged to be certain 
 things subsisting beyond our mind, we are wholly una- 
 ble to form any conception of them. Indeed, when 
 ■any one tells us that he sees colour in a body or feels 
 
PART I. 167 
 
 pain in one of his limbs, this is exactly the same as if 
 he said that he there saw or felt something of the na- 
 ture of which he was entirely ignorant, or that he did 
 not know what he saw or felt. For although, when 
 less attentively examining his thoughts, a person may 
 easily persuade himself that he has some knowledge of 
 it, since he supposes that there is something resem- 
 bling that sensation of colour or of pain of which he is 
 conscious ; yet, if he reflects on what the sensation of 
 colour or pain represents to him as existing in a 
 coloured body or in a wounded member, he will find 
 that of such he has absolutely no knowledge. 
 
 LXIX. That magnitude, figure, etc., are known far 
 differently from colour, pain, etc. 
 
 What we have said above will be more manifest, 
 especially if we consider that size in the body perceived, 
 figure, motion (at least local, for philosophers by 
 fancying other kinds of motion have rendered its na- 
 ture less intelligible to themselves), the situation of 
 parts, duration, number, and those other properties 
 which, as we have already said, we clearly perceive in 
 all bodies, are known by us in a way altogether differ- 
 ent from that in which we know what colour is in the 
 same body, or pain, smell, taste, or any other of those 
 properties which I have said above must be referred to 
 the senses. For although when we see a body we are 
 not less assured of its existence from its appearing 
 figured than from its appearing coloured,* we yet 
 know with far greater clearness its property of figure 
 than its colour. 
 
 LXX. That we may judge of sensible things in two 
 
 * " by the colour we perceive on occasion of it." — French. 
 
168 THE PRINCIPLES OF PHILOSOPHY. 
 
 ways, by the one of which we avoid error, by the other 
 fall into it. 
 
 It is thus manifest that to say we perceive colours in 
 objects is in reality equivalent to saying we perceive 
 something in objects and are yet ignorant of what it is, 
 except as that which determines in us a certain highly 
 vivid and clear sensation, which we call the sensation 
 of colours. There is, however, very great diversity in 
 the manner of judging: for so long as we simply judge 
 that there is an unknown something in objects (that is, 
 in things such as they are, from which the sensation 
 reached us), so far are we from falling into error that, 
 on the contrary, we thus rather provide against it, for 
 we are less apt to judge rashly of a thing which we 
 observe we do not know. But when we think we per- 
 ceive colours in objects, although we are in reality ig- 
 norant of what we then denominate colour, and are 
 unable to conceive any resemblance between the col- 
 our we suppose to be in objects, and that of which we 
 are conscious in sensation, yet because we do not ob- 
 serve this, or becausethere are in objects several prop- 
 erties, as size, figure, number, etc., which, as we clearly 
 know, exist, or may exist in them as they are perceived 
 by our senses or conceived by our understanding, we 
 easily glide into the error of holding that what is called 
 colour in objects is something entirely resembling the 
 colour we perceive, and thereafter of supposing that 
 we have a clear perception of what is in no way per- 
 ceived by us. 
 
 LXXI. That the chief cause of our errors is to be 
 found in the prejudices of our childhood. 
 
 And here we may notice the first and chief cause of 
 our errors. In early life the mind was so closely 
 
PART I. 169 
 
 bound to the body that it attended to nothing beyond 
 the thoughts by which it perceived the objects that 
 made impression on the body : nor as yet did it refer 
 these thoughts to anything existing beyond itself, but 
 simply felt pain when the body was hurt, or pleasure 
 when anything beneficial to the body occurred, or if 
 the body was so highly affected that it was neither 
 greatly benefited nor hurt, the mind experienced the 
 sensations we call tastes, smells, sounds, heat, cold, 
 light, colours, and the like, which in truth are repre- 
 sentative of nothing existing out of our mind, and 
 which vary according to the diversities of the parts 
 and modes in which the body is affected.* The mind 
 at the same time also perceived magnitudes, figures, 
 motions, and the like, which were not presented to it 
 as sensations but as things or the modes of things ex- 
 isting, or at least capable of existing out of thought, 
 although it did not yet observe this difference between 
 these two kinds of perceptions. And afterwards when 
 the machine of the body, which has been so fabricated 
 by nature that it can of its own inherent power move 
 itself in various ways, by turning itself at random on 
 every side, followed after what was useful and avoided 
 what was detrimental ; the mind, which was closely 
 connected with it, reflecting on the objects it pursued 
 or avoided, remarked, for the first time, that they ex- 
 isted out of itself, and not only attributed to them 
 magnitudes, figures, motions, and the like, which it 
 apprehended either as things or as the modes of things, 
 
 * "which vary according to the diversities of the move- 
 ments that pass from all parts of our body to the part of the 
 brain to which it (the mind) is closely joined and united." — 
 French. 
 
170 THE PRINCIPLES OF PHILOSOPHY. 
 
 but, in addition, attributed to them tastes, odours, and 
 the other ideas of that sort, the sensations of which 
 were caused by itself ;* and as it only considered other 
 objects in so far as they were useful to the body, in 
 which it was immersed, it judged that there was 
 greater or less reality in each object, according as the 
 impressions it caused on the body were more or less 
 powerful. Hence arose the belief that there was more 
 substance or body in rocks and metals than in air or 
 water, because the mind perceived in them more hard- 
 ness and weight. Moreover, the air was thought to 
 be merely nothing so long as we experienced no agi- 
 tation of it by the wind, or did not feel it hot or cold. 
 And because the stars gave hardly more light than the 
 slender flames of candles, we supposed that each star 
 was but of this size. Again, since the mind did not 
 observe that the earth moved on its axis, or that its 
 superficies was curved like that of a globe, it was on 
 that account more ready to judge the earth immovable 
 and its surface flat. And our mind has been imbued 
 from our infancy with a thousand other prejudices of 
 the same sort which afterwards in our youth we for- 
 got we had accepted without sufficient examination, 
 and admitted as possessed of the highest truth and 
 clearness, as if they had been known by means of our 
 senses, or implanted in us by nature. 
 
 LXXII. That the second cause of our errors is that 
 we cannot forget these prejudices. 
 
 And although now in our mature years, when the 
 mind, being no longer wholly subject to the body, is 
 not in the habit of referring all things to it, but also 
 
 * "which it perceived on occasion of them" (•£ e., of exter- 
 nal objects). — French. 
 
PART I. 171 
 
 seeks to discover the truth of things considered in 
 themselves, we observe the falsehood of a great many 
 of the judgments we had before formed; yet we ex- 
 perience a difficulty in expunging them from our mem- 
 ory, and, so long as they remain there, they give rise 
 to various errors. Thus, for example, since from our 
 earliest years we imagined the stars to be of very small 
 size, we find it highly difficult to rid ourselves of this 
 imagination, although assured by plain astronomical 
 reasons that they are of the greatest, — so prevailing is 
 the power of preconceived opinion. 
 
 LXXIII. The third cause is, that we become fa- 
 tigued by attending to those objects which are not 
 present to the senses ; and that we are thus accustomed 
 to judge of these not from present perception but from 
 pre-conceived opinion. 
 
 Besides, our mind cannot attend to any object with- 
 out at length experiencing some pain and fatigue ; and 
 of all objects it has the greatest difficulty in attending 
 to those which are present neither to the senses nor 
 to the imagination: whether for the reason that this 
 is natural to it from its union with the body, or be- 
 cause in our early years, being occupied merely with 
 perceptions and imaginations, it has become more fa- 
 miliar with, and acquired greater facility in thinking 
 in those modes than in any other. Hence it also hap- 
 pens that many are unable to conceive any substance 
 except what is imaginable and corporeal, and even sen- 
 sible. For they are ignorant of the circumstance, that 
 those objects alone are imaginable which consist in ex- 
 tension, motion, and figure, while there are many oth- 
 ers besides these that are intelligible; and they per- 
 suade themselves that nothing can subsist but body, 
 
172 THE PRINCIPLES OF PHILOSOPHY. 
 
 and, finally, that there is no body which is not sensible. 
 And since in truth we perceive no object such as it is 
 by sense alone [but only by our reason exercised upon 
 sensible objects], as will hereafter be clearly shown, 
 it thus happens that the majority during life perceive 
 nothing unless in a confused way. 
 
 LXXIV. The fourth source of our errors is, that we 
 attach our thoughts to words which do not express 
 them with accuracy. 
 
 Finally, since for the use of speech we attach all our 
 conceptions to words by which to express them, and 
 commit to memory our thoughts in connection with 
 these terms, and as we afterwards find it more easy 
 to recall the words than the things signified by them, 
 we can scarcely conceive anything with such distinct- 
 ness as to separate entirely what we conceive from the 
 words that were selected to express it. On this ac- 
 count the majority attend to words rather than to 
 things ; and thus very frequently assent to terms with- 
 out attaching to them any meaning, either because 
 they think they once understood them, or imagine they 
 received them from others by whom they were cor- 
 rectly understood. This, however, is not the place to 
 treat of this matter in detail, seeing the nature of the 
 human body has not yet been expounded, nor the ex- 
 istence even of body established ; enough, neverthe- 
 less, appears to have been said to enable one to distin- 
 guish such of our conceptions as are clear and distinct 
 from those that are obscure and confused. 
 
 LXXV. Summary of what must be observed in or- 
 der to philosophize correctly. 
 
 Wherefore if we would philosophize in earnest, and 
 give ourselves to the search after all the truths we are 
 
PART I. 173 
 
 capable of knowing, we must, in the first place, lay 
 aside our prejudices ; in other words, we must take 
 care scrupulously to withhold our assent from the 
 opinions we have formerly admitted, until upon new 
 examination we discover that they are true. We 
 must, in the next place, make an orderly review of the 
 notions we have in our minds, and hold as true all and 
 only those which we will clearly and distinctly appre- 
 hend. In this way we will observe, first of all, that 
 we exist in so far as it is our nature to think, and at 
 the same time that there is a God upon whom we de- 
 pend; and after considering his attributes we will be 
 able to investigate the truth of all other things, since 
 God is the cause of them. Besides the notions we 
 have of God and of our mind, we will likewise find that 
 we possess the knowledge of many propositions which 
 are eternally true, as, for example, that nothing can- 
 not be the cause of anything, etc. We will farther 
 discover in our minds the knowledge of a corporeal 
 or extended nature that may be moved, divided, etc., 
 and also of certain sensations that affect us, as of pain, 
 colours, tastes, etc., although we do not yet know the 
 cause of our being so affected; and, comparing what 
 we have now learne'd, by examining those things in 
 their order, with our former confused knowledge of 
 them, we will acquire the habit of forming clear and 
 distinct conceptions of all the objects we are capable 
 of knowing. In these few precepts seem to me to be 
 comprised the most general and important principles 
 of human knowledge. 
 
 LXXVI. That we ought to prefer the Divine au- 
 thority to our perception ;* but that, apart from things 
 * " reasonings." — French. 
 
174 THE PRINCIPLES OF PHILOSOPHY. 
 
 revealed, we ought to assent to nothing that we do not 
 clearly apprehend. 
 
 Above all, we must impress on our memory the in- 
 fallible rule, that what God has revealed is incompar- 
 ably more certain than anything else ; and that we 
 ought to submit our belief to the Divine authority 
 rather than to our own judgment, even although per- 
 haps the light of reason should, with the greatest clear- 
 ness and evidence, appear to suggest to us something 
 contrary to what is revealed. But in things regarding 
 which there is no revelation, it is by no means con- 
 sistent with the character of a philosopher to accept 
 as true what he has not ascertained to be such, and 
 to trusf more to the senses, in other words, to the in- 
 considerate judgments of childhood than to the dic- 
 tates of mature reason. 
 
PART IL 
 
 OF THE PRINCIPLES OF MATERIAL THINGS. 
 
 I. The grounds on which the existence of material 
 things may be known with certainty. 
 
 Although we are all sufficiently persuaded of the ex- 
 istence of material things, yet, since this was before 
 called in question by us, and since we reckoned the per- 
 suasion of their existence as among the prejudices of 
 our childhood, it is now necessary for us to investigate 
 the grounds on which this truth may be known with 
 certainty. In the first place, then, it cannot be doubted 
 that every perception we have comes to us from some 
 object different from our mind; for it is not in our 
 power to cause ourselves to experience one perception 
 rather than another, the perception being entirely de- 
 pendent on the object which affects our senses. It 
 may, indeed, be matter of inquiry whether that object 
 be God, or something different from God ; but because 
 we perceive, or rather, stimulated by sense, clearly and 
 distinctly apprehend, certain matter extended in length, 
 breadth, and thickness, the various parts of which have 
 different figures and motions, and give rise to the sen- 
 sation we have of colours, smells, pain, etc., God would, 
 without question, deserve to be regarded as a deceiver, 
 if he directly and of himself presented to our mind the 
 idea of this extended matter, or merely caused it to 
 be presented to us by some object which possessed 
 neither extension, figure, nor motion. For we clearly 
 175 
 
176 THE PRINCIPLES OF PHILOSOPHY. 
 
 conceive this matter as entirely distinct from God, and 
 from ourselves, or our mind ; and appear even clearly 
 to discern that the idea of it is formed in us on occasion 
 of objects existing out of our minds, to which it is 
 in every respect similar. But since God cannot de- 
 ceive us, for this is repugnant to his nature, as has 
 been already remarked, we must unhesitatingly con- 
 clude that there exists a certain object extended in 
 length, breadth, and thickness, and possessing all those 
 properties which we clearly apprehend to belong to 
 what is extended. And this extended substance is 
 what we call body or matter. 
 
 II. How we likewise know that the human body is 
 closely connected with the mind. 
 
 We ought also to conclude that a certain body is 
 more closely united to our mind than any other, be- 
 cause we clearly observe that pain and other sensations 
 affect us without our foreseeing them ; and these, the 
 mind is conscious, do not arise from itself alone, nor 
 pertain to it, in so far as it is a thing which thinks,but 
 only in so far as it is united to another thing extended 
 and movable, which is called the human body. But 
 this is not the place to treat in detail of this matter. 
 
 III. That the perceptions of the senses do not teach 
 us what is in reality in things, but what is beneficial or 
 hurtful to the composite whole of mind and body. 
 
 It will be sufficient to remark that the perceptions 
 of the senses are merely to be referred to this intimate 
 union of the human body and mind, and that they usu- 
 ally make us aware of what, in external objects, may 
 be useful or adverse to this union, but do not present 
 to us these objects as they are in themselves, unless 
 occasionally and by accident. For, after this obser- 
 
PART II. 177 
 
 vation, we will without difficulty lay aside the preju- 
 dices of the senses, and will have recourse to our 
 understanding alone on this question by reflecting 
 carefully on the ideas implanted in it by nature. 
 
 IV. That the nature of body consists not in weight 
 hardness, colour and the like, but in extension alone. 
 
 In this way we will discern that the nature of mat- 
 ter or body, considered in general, does not consist in 
 its being hard, or ponderous, or coloured, or that 
 which affects our senses in any other way, but simply 
 in its being a substance extended in length, breadth, 
 and depth. For with respect to hardness, we know 
 nothing of it by sense farther than that the parts of 
 hard bodies resist the motion of our hands on coming 
 into contact with them ; but if every, time our hands 
 moved towards any part, all the bodies in that place 
 receded as quickly as our hands approached, we 
 should never feel hardness ; and yet we have no rea- 
 son to believe that bodies which might thus recede 
 would on this account lose that which makes them 
 bodies. The nature of body does not, therefore, con- 
 sist in hardness. In the same way, it may be 
 shown that weight, colour, and all the other qualities 
 of this sort, which are perceived in corporeal matter, 
 may be taken from it, itself meanwhile remaining en- 
 tire : it thus follows that the nature of body depends 
 on none of these. 
 
 V. That the truth regarding the nature of body is 
 obscured by the opinions respecting rarefaction and 
 a vacuum with which we are pre-occupied. 
 
 There still remain two causes to prevent its being 
 fully admitted that the true nature of body consists in 
 extension alone. The first is the prevalent opinion, 
 
178 THE PRINCIPLES OF PHILOSOPHY. 
 
 that most bodies admit of being so rarefied and con- 
 densed that, when rarefied, they have greater exten- 
 sion than when condensed; and some even have sub- 
 tilized to such a degree as to make a distinction be- 
 tween the substance of body and its quantity, and be- 
 tween quantity itself and extension. The second cause 
 is this, that where we conceive only extension in 
 length, breadth, and depth, we are not in the habit of 
 saying that body is there, but only space and further 
 void space, which the generality believe to be a mere 
 negation. 
 
 VI. In what way rarefaction takes place. 
 
 But with regard to rarefaction and condensation, 
 whoever gives his attention to his own thoughts, and 
 admits nothing of which he is not clearly conscious, 
 will not suppose that there is anything in those proc- 
 esses further than a change of figure in the body rare- 
 fied or condensed : so that, in other words, rare bodies 
 are those between the parts of which there are num- 
 erous distances filled with other bodies; and dense 
 bodies, on the other hand, those whose parts approach- 
 ing each other, either diminish these distances or take 
 them wholly away, in the latter of which cases the 
 body is rendered absolutely dense. The body, how- 
 ever, when condensed, has not, therefore, less exten- 
 sion than when the parts embrace a greater space, 
 owing to their removal from each other, and their dis- 
 persion into branches. For we ought not to attribute 
 to it the extension of the pores or distances which its 
 parts do not occupy when it is rarefied, but to the 
 other bodies that fill these interstices; just as when 
 we see a sponge full of water or any other liquid, we 
 do not suppose that each part of the sponge has on 
 
PART IL 179 
 
 this account greater extension than when compressed 
 and dry, but only that its pores are wider, and there- 
 fore that the body is diffused over a larger space. 
 
 VII. That rarefaction cannot be intelligibly ex- 
 plained unless in the way here proposed. 
 
 And indeed I am unable to discover the force of the 
 reasons which have induced some to say that rarefac- 
 tion is the result of the augmentation of the quantity 
 of body, rather than to explain it on the principle ex- 
 emplified in the case of a sponge. For although when 
 air or water is rarefied we do not see any of the pores 
 that are rendered large, or the new body that is added 
 to occupy them, it is yet less agreeable to reason to 
 suppose something that is unintelligible for the pur- 
 pose of giving a verbal and merely apparent explana- 
 tion of the rarefaction of bodies, than to conclude, be- 
 cause of theit rarefaction, that there are pores or dis- 
 tances between the parts which are increased in size, 
 and filled with some new body. Nor ought we to re- 
 frain from assenting to this explanation, because we 
 perceive this new body by none of our senses, for 
 there is no reason which obliges us to believe that we 
 should perceive by our senses all the bodies in exist- 
 ence. And we see that it is very easy to explain rare- 
 faction in this manner, but impossible in any other; 
 for, in fine, there would be, as appears to me, a mani- 
 fest contradiction in supposing that any body was in- 
 creased by a quantity or extension which it had not 
 before, without the addition to it of a new extended 
 substance, in other words, of another body, because 
 it is impossible to conceive any addition of extension 
 or quantity to a thing without supposing the addition 
 
i8o THE PRINCIPLES OF PHILOSOPHY. 
 
 of a substance having quantity or extension, as will 
 more clearly appear from what follows. 
 
 VIII. That quantity and number differ only in 
 thought (ratione) from that which has quantity and 
 is numbered. 
 
 For quantity differs from extended substance, and 
 number from what is numbered, not in reality but 
 merely in our thought; so that, for example, w é e may 
 consider the whole nature of a corporeal substance 
 which is comprised in a space of ten feet, although we 
 do not attend to this measure of ten feet, for the ob- 
 vious reason that the thing conceived is of the same 
 nature in any part of that space as in the whole ; and, 
 on the other hand, we can conceive the number ten, 
 as also a continuous quantity of ten feet, without 
 thinking of this determinate substance, because the 
 concept of the number ten is manifestly the same 
 whether we consider a number of ten feet or ten of any- 
 thing else ; and we can conceive a continuous quantity 
 of ten feet without thinking of this or that determin- 
 ate substance, although we cannot conceive it without 
 some extended substance of which it is the quantity. 
 It is in reality, however, impossible that any, even the 
 least part, of such quantity or extension, can be taken 
 away, without the retrenchment at the same time of 
 as much of the substance, nor, on the other hand, can 
 we lessen the substance, without at the same time tak- 
 ing as much from the quantity or extension. 
 
 IX. That corporeal substance, when distinguished 
 from its quantity, is confusedly conceived as some- 
 thing incorporeal. 
 
 Although perhaps some express themselves other- 
 wise on this matter, I am nevertheless convinced that 
 
PART IL 181 
 
 they do not think differently from what I have now 
 said: for when they distinguish (corporeal) substance 
 from extension or quantity, they either mean nothing 
 by the word (corporeal) substance, or they form in 
 their minds merely a confused idea of incorporeal sub- 
 stance, which they falsely attribute to corporeal, and 
 leave to extension the true idea of this corporeal sub- 
 stance ; which extension they call an accident, but with 
 such impropriety as to make it easy to discover that 
 their words are not in harmony with their thoughts. 
 
 X. Wliat space or internal place is. 
 
 Space or internal place, and the corporeal substance 
 which is comprised in it, are not different in reality, 
 but merely in the mode in which they are wont to be 
 conceived by us. For, in truth, the same extension 
 in length, breadth, and depth, which constitutes space, 
 constitutes body ; and the difference between them lies 
 only in this, that in body we consider extension as 
 particular, and conceive it to change with the body ; 
 whereas in space we attribute to extension a generic 
 unity, so that after taking from a certain space the 
 body which occupied it, we do not suppose that we 
 have at the same time removed the extension of the 
 space, because it appears to us that the same extension 
 remains there so long as it is of the same magnitude 
 and figure, and preserves the same situation in respect 
 to certain bodies around it, by means of which we 
 determine this space. 
 
 XI. How space is not in reality different from cor- 
 poreal substance. 
 
 And indeed it will be easy to discern that it is the 
 same extension which constitutes the nature of body 
 as of space, and that these two things are mutually di- 
 
i8a THE PRINCIPLES OF PHILOSOPHY. 
 
 verse only as the nature of the genus and species dif- 
 fers from that of the individual, provided we reflect 
 on the idea we have of any body, taking a stone for 
 example, and reject all that is not essential to the na- 
 ture of body. In the first place, then, hardness may 
 be rejected, because if the stone were liquefied or re- 
 duced to powder, it would no longer possess hard- 
 ness, and yet would not cease to be a body; colour 
 also may be thrown out of account, because we have 
 frequently seen stones so transparent as to have no 
 colour ; again, we may reject weight, because we have 
 the case of fire, which, though very light, is still a 
 body; and, finally, we may reject cold, heat, and all 
 the other qualities of this sort, either because they 
 are not considered as in the stone, or because, with 
 the change of these qualities, the stone is not supposed 
 to have lost the nature of body. After this examina- 
 tion we will find that nothing remains in the idea of 
 body, except that it is something extended in length, 
 breadth, and depth; and this something is comprised 
 in our idea of space, not only of that which is full of 
 body, but even of what is called void space. 
 
 XII. How space differs from body in our mode of 
 conceiving it. 
 
 There is, however, some difference between them 
 in the mode of conception; for if we remove a stone 
 from the space or place in which it was, we conceive 
 that its extension also is taken away, because we 
 regard this as particular, and inseparable from the 
 stone itself: but meanwhile we suppose that the same 
 extension of place in which this stone was remains, 
 although the place of the stone be occupied by wood, 
 water, air, or by any other body, or be even supposed 
 
PART IL 183 
 
 vacant, because we now consider extension in general, 
 and think that the same is common to stones, wood, 
 water, air, and other bodies, and even to a vacuum 
 itself, if there is any such thing, provided it be of the 
 same magnitude and figure as before, and preserve 
 the same situation among the external bodies which 
 determine this space. 
 
 XIII. What external place is. 
 
 The reason of which is, that the words place and 
 space signify nothing really different from body which 
 is said to be in place, but merely designate its magni- 
 tude, figure, and situation among other bodies. For 
 it is necessary, in order to determine this situation, 
 to regard certain other bodies which we consider as 
 immovable; and, according as we look to different 
 bodies, we may see that the same thing at the same 
 time does and does not change place. For example, 
 when a vessel is being carried out to sea, a person sit- 
 ting at the stern may be said to remain always in one 
 place, if we look to the parts of the vessel, since with 
 respect to these he preserves the same situation; and 
 on the other hand, if regard be had to the neighbour- 
 ing shores, the same person will seem to be perpetually 
 changing place, seeing he is constantly receding from 
 one shore and approaching another. And besides, if 
 we suppose that the earth moves, and that it makes 
 precisely as much way from west to east as the vessel 
 from east to west, we will again say that the person 
 at the stern does not change his place, because this 
 place will be determined by certain immovable points 
 which we imagine to be in the heavens. But if at 
 length we are persuaded that there are no points really 
 immovable in the universe, as will hereafter be shown 
 
i84 THE PRINCIPLES OF PHILOSOPHY. 
 
 to be probable, we will thence conclude that nothing 
 has a permanent place unless in so far as it is fixed 
 by our thought. 
 
 XIV. Wherein place and space differ. 
 
 The terms place and space, however, differ in sig- 
 nification, because place more expressly designates 
 situation than magnitude or figure, while, on the other 
 hand, we think of the latter when we speak of space. 
 For we frequently say that a thing succeeds to the 
 place of another, although it be not exactly of the 
 same magnitude or figure; but we do not therefore 
 admit that it occupies the same space as the other ; 
 and when the situation is changed we say that the 
 place also is changed, although there are the same 
 magnitude and figure as before : so that when we say 
 that a thing is in a particular place, we mean merely 
 that it is situated in a determinate way in respect of 
 certain other objects ; and when we add that it occu- 
 pies such a space or place, we understand besides that 
 it is of such determinate magnitude and figure as ex- 
 actly to fill this space. 
 
 XV. How external place is rightly taken for the 
 superficies of the surrounding body. 
 
 And thus we never indeed distinguish space from 
 extension in length, breadth, and depth ; we sometimes, 
 however, consider place as in the thing placed, and at 
 other times as out of it. Internal place indeed differs 
 in no way from space ; but external place may be taken 
 for the superficies that immediately surrounds the thing 
 placed. It ought to be remarked that by superficies 
 we do not here understand any part of the surround- 
 ing body, but only the boundary between the surround- 
 ing and surrounded bodies, which is nothing more than 
 
PART II. 185 
 
 a mode ; or at least that we speak of superficies in gen- 
 eral which is no part of one body rather than another, 
 but is always considered the same, provided it retain 
 the same magnitude and figure. For although the 
 whole surrounding body with its superficies were 
 changed, it would not be supposed that the body which 
 was surrounded by it had therefore changed its place, 
 if it meanwhile preserved the same situation with re- 
 spect to the other bodies that are regarded as immov- 
 able. Thus, if we suppose that a boat is carried in 
 one direction by the current of a stream, and impelled 
 by the wind in the opposite with an equal force, so 
 that its situation with respect to the banks is not 
 changed, we will readily admit that it remains in the 
 same place, although the whole superficies which sur- 
 rounds it is incessantly changing. 
 
 XVI. That a vacuum or space in which there is 
 absolutely no body is repugnant to reason. 
 
 With regard to a vacuum, in the philosophical sense 
 of the term, that is, a space in which there is no sub- 
 stance, it is evident that such does not exist, seeing 
 the extension of space or internal place is not differ- 
 ent from that of body. For since from this alone, that 
 a body has extension in length, breadth, and depth, 
 we have reason to conclude that it is a substance, it 
 being absolutely contradictory that nothing should 
 possess extension, we ought to form a similar infer- 
 ence regarding the space which is supposed void, viz., 
 that since there is extension in it there is necessarily 
 also substance. 
 
 XVII. That a vacuum in the ordinary use of the 
 term does not exclude all body. 
 
 And, in truth, by the term vacuum in its common 
 
i86 THE PRINCIPLES OF PHILOSOPHY. 
 
 use, we do not mean a place or space in which there 
 is absolutely nothing, but only a place in which there 
 is none of those things we presume ought to be there. 
 Thus, because a pitcher is made to hold water, it is 
 said to be empty when it is merely filled with air; or 
 if there are no fish in a fish-pond, we say there is 
 nothing in it, although it be full of water ; thus a ves- 
 sel is said to be empty, when, in place of the merchan- 
 dise which it was designed to carry, it is loaded with 
 sand only, to enable it to resist the violence of the 
 wind; and, finally, it is in the same sense that we say 
 space is void when it contains nothing sensible, al- 
 though it contain created and self -subsisting matter; 
 for we are not in the habit of considering the bodies 
 near us, unless in so far as they cause in our organs 
 of sense, impressions strong enough to enable us to 
 perceive them. And if, in place of keeping in mind 
 what ought to be understood by these terms a vacuum 
 and nothing, we afterwards suppose that in the space 
 we called a vacuum, there is not only no sensible ob- 
 ject, but no object at all, we will fall into the same 
 error as if, because a pitcher in which there is noth- 
 ing but air, is, in common speech, said to be empty, 
 we were therefore to judge that the air contained in 
 it is not a substance {res subsistens). 
 
 XVIII. How the prejudice of an absolute vacuum 
 is to be corrected. 
 
 We have almost all fallen into this error from the 
 earliest age, for, observing that there is no necessary 
 connection between a vessel and the body it contains, 
 we thought that God at least could take from a vessel 
 the body which occupied it, without it being necessary 
 that any other should be put in the place of the one 
 
PART IL 187 
 
 removed. But that we may be able now to correct 
 this false opinion, it is necessary to remark that there 
 is in truth no connection between the vessel and the 
 particular body which it contains, but that there is an 
 absolutely necessary connection between the concave 
 figure of the vessel and the extension considered gen- 
 erally which must be comprised in this cavity ; so that 
 it is not more contradictory to conceive a mountain 
 without a valley than such a cavity without the ex- 
 tension it contains, or this extension apart from an 
 extended substance, for, as we have often said, of 
 nothing there can be no extension. And accordingly, 
 if it be asked what would happen were God to remove 
 from a vessel all the body contained in it, without per- 
 mitting another body to occupy its place, the answer 
 must be that the sides of the vessel would thus come 
 into proximity with each other. For two bodies must 
 touch each other when there is nothing between them, 
 and it is manifestly contradictory for two bodies to 
 be apart, in other words, that there should be a dis- 
 tance between them, and this distance yet be nothing; 
 for all distance is a mode of extension, and cannot 
 therefore exist without an extended substance. 
 
 XIX. That this confirms what was said of rarefac- 
 tion. 
 
 After we have thus remarked that the nature of cor- 
 poreal substance consists only in its being an extended 
 thing, and that its extension is not different from that 
 which we attribute to space, however empty, it is easy 
 to discover the impossibility of any one of its parts in 
 any way whatsoever occupying more space at one time 
 than at another, and thus of being otherwise rarefied 
 than in the way explained above ; and it is easy to per- 
 
i88 THE PRINCIPLES OF PHILOSOPHY. 
 
 ceive also that there cannot be more matter or body in 
 a vessel when it is filled with lead or gold, or any other 
 body however heavy and hard, than when it but con- 
 tains air and is supposed to be empty : for the quan- 
 tity of the parts of which a body is composed does not 
 depend on their weight or hardness, but only on the 
 extension, which is always equal in the same vase. 
 
 XX. That from this the non-existence of atoms 
 may likewise be demonstrated. 
 
 We likewise discover that there cannot exist any 
 atoms or parts of matter that are of their own nature 
 indivisible. For however small we suppose these parts 
 to be, yet because they are necessarily extended, we 
 are always able in thought to divide any one of them 
 into two or more smaller parts, and may accordingly 
 admit their divisibility. For there is nothing we can 
 divide in thought which we do not thereby recognize 
 to be divisible; and, therefore, were we to judge it in- 
 divisible our judgment would not be in harmony with 
 the knowledge we have of the thing ; and although we 
 should even suppose that God had reduced any particle 
 of matter to a smallness so extreme that it did not 
 admit of being further divided, it would nevertheless 
 be improperly styled indivisible, for though God had 
 rendered the particle so small that it was not in the 
 power of any creature to divide it, he could not how- 
 ever deprive himself of the ability to do so, since it is 
 absolutely impossible for him to lessen his own om- 
 nipotence, as was before observed. Wherefore, abso- 
 lutely speaking, the smallest extended particle is al- 
 ways divisible, since it is such of its very nature. 
 
 XXI. It is thus also demonstrated that the exten- 
 sion of the world is indefinite. 
 
PART II. 189 
 
 We further discover that this world or the whole 
 (universitas) of corporeal substance, is extended with- 
 out limit, for wherever we fix a limit, we still not only 
 imagine beyond it spaces indefinitely extended, but 
 perceive these to be truly imaginable, in other words, 
 to be in reality such as we imagine them ; so that they 
 contain in them corporeal substance indefinitely ex- 
 tended, for, as has been already shown at length, the 
 idea of extension which we conceive in any space what- 
 ever is plainly identical with the idea of corporeal sub- 
 stance. 
 
 XXII. It also follows that the matter of the heavens 
 and earth is the same, and that there cannot be a plur- 
 ality of worlds. 
 
 And it may also be easily inferred from all this that 
 the earth and heavens are made of the same matter; 
 and that even although there were an infinity of 
 worlds, they would all be composed of this matter ; 
 from which it follows that a plurality of worlds is im- 
 possible, because we clearly conceive that the matter 
 whose nature consists only in its being an extended 
 substance, already wholly occupies all the imaginable 
 spaces where these other worlds could alone be, and we 
 cannot find in ourselves the idea of any other matter. 
 
 XXIII. That all the variety of matter, or the di- 
 versity of its forms, depends on motion. 
 
 There is therefore but one kind of matter in the 
 whole universe, and this we know only by its being ex- 
 tended. All the properties we distinctly perceive to 
 belong to it are reducible to its capacity of being di- 
 vided and moved according to its parts; and accord- 
 ingly it is capable of all those affections which we per- 
 ceive can arise from the motion of its parts. For the 
 
190 THE PRINCIPLES OF PHILOSOPHY. 
 
 partition of matter in thought makes no change in it ; 
 but all variation of it, or diversity of form, depends on 
 motion. The philosophers even seem universally to 
 have observed this, for they said that nature was the 
 principle of motion and rest, and by nature they under- 
 stood that by which all corporeal things become such 
 as they are found in experience. 
 
 XXIV. What motion is, taking the term in its 
 common use. 
 
 But motion (viz., local, for I can conceive no other 
 kind of motion, and therefore I do not think we ought 
 to suppose there is any other in nature), in the ordi- 
 nary sense of the term, is nothing more than the action 
 by which a body passes from one place to another. 
 And just as we have remarked above that the same 
 thing may be said to change and not to change place 
 at the same time, so also we may say that the same 
 thing is at the same time moved and not moved. Thus, 
 for example, a person seated in a vessel which is set- 
 ting sail, thinks he is in motion if he look to the shore 
 that he has left, and consider it as fixed ; but not if he 
 regard the ship itself, among the parts of which he 
 preserves always the same situation. Moreover, be- 
 cause we are accustomed to suppose that there is no 
 motion without action, and that in rest there is the 
 cessation of action, the person thus seated is more 
 properly said to be at rest than in motion, seeing he is 
 not conscious of being in action. 
 
 XXV. What motion is properly so called. 
 
 But if, instead of occupying ourselves with that 
 which has no foundation, unless in ordinary usage, we 
 desire to know what ought to be understood by mo- 
 tion according to the truth of the thing, we may say, 
 
PART IL 191 
 
 in order to give it a determinate nature, that it is the 
 transporting of one part of matter or of one body from 
 the vicinity of those bodies that are in immediate con- 
 tact with it, or which we regard as at rest, 9 to the 
 vicinity of other bodies. By a body as a part of mat- 
 ter, I understand all that which is transferred together, 
 although it be perhaps composed of several parts, 
 which in themselves have other motions; and I say 
 that it is the transporting and not the force or action 
 which transports, with the view of showing that mo- 
 tion is always in the movable thing, not in that which 
 moves ; for it seems to me that we are not accustomed 
 to distinguish these two things with sufficient accur- 
 acy. Farther, I understand that it is a mode of the 
 movable thing, and not a substance, just as figure is 
 a property of the thing figured, and repose of that 
 which is at rest. 
 
PART III. 
 
 OF THE VISIBLE WORLD. 
 
 I. That we cannot think too highly of the works of 
 God. 
 
 Having now ascertained certain principles of mate- 
 rial things, which were sought, not by the prejudices 
 of the senses, but by the light of reason, and which 
 thus possess so great evidence that we cannot doubt of 
 their truth, it remains for us to consider whether from 
 these alone we can deduce the explication of all the 
 phenomena of nature. We will commence with those 
 phenomena that are of the greatest generality, and 
 upon which the others depend, as, for example, with 
 the general structure of this whole visible world. But 
 in order to our philosophizing aright regarding this, 
 two things are first of all to be observed. The first is, 
 that we should ever bear in mind the infinity of the 
 power and goodness of God, that we may not fear fall- 
 ing into error by imagining his works to be too great, 
 beautiful, and perfect, but that we may, on the con- 
 trary, take care lest, by supposing limits to them of 
 which we have no certain knowledge, we appear to 
 think less highly than we ought of the power of God. 
 
 II. That we ought to beware lest, in our presump- 
 tion, we imagine that the ends which God proposed to 
 himself in the creation of the world are understood by 
 us. 
 
 The second is, that we should beware of presuming 
 192 
 
PART III. 193 
 
 too highly of ourselves, as it seems we should do if we 
 supposed certain limits to the world, without being as- 
 sured of their existence either by natural reasons or by 
 divine revelation, as if the power of our thought ex- 
 tended beyond what God has in reality made ; but like- 
 wise still more if we persuaded ourselves that all 
 things were created by God for us only, or if we 
 merely supposed that we could comprehend by the 
 power of our intellect the ends which God proposed to 
 himself in creating the universe. 
 
 III. In what sense it may be said that all things 
 were created for the sake of man. 
 
 For although, as far as regards morals, it may be a 
 pious thought to believe that God made all things for 
 us, seeing we may thus be incited to greater gratitude 
 and love toward him ; and although it is even in some 
 sense true, because there is no created thing of which 
 we cannot make some use, if it be only that of exercis- 
 ing our mind in considering it, and honouring God on 
 account of it, it is yet by no means probable that all 
 things were created for us in this way that God had no 
 other end in their creation ; and this supposition would 
 be plainly ridiculous and inept in physical reasoning, 
 for we do not doubt but that many things exist, or 
 formerly existed and have now ceased to be, which 
 were never seen or known by man, and were never of 
 use to him. 
 
PART IV. 
 
 OF THE EARTH. 
 
 CLXXXVIII. Of what is to be borrowed from 
 disquisitions on animals and man to advance the 
 knowledge of material objects. 
 
 I should a'dd nothing farther to this the Fourth Part 
 of the Principles of Philosophy, did I purpose carry- 
 ing out my original design of writing a Fifth and 
 Sixth Part, the one treating of things possessed of 
 life, that is, animals and plants, and the other of man. 
 But because I have not yet acquired sufficient knowl- 
 edge of all the matters of which I should desire to 
 treat in these two last parts, and do not know whether 
 I shall ever have sufficient leisure to finish them, I will 
 here subjoin a few things regarding the objects of our 
 senses, that I may not, for the sake of the latter, delay 
 too long the publication of the former parts, or of what 
 may be desiderated in them, which I might have re- 
 served for explanation in those others: for I have 
 hitherto described this earth, and generally the whole 
 visible world, as if it were merely a machine in which 
 there was nothing at all to consider except the figures 
 and motions of its parts, whereas our senses present to 
 us many other things, for example colours, smells, 
 sounds, and the like, of which, if I did not speak at all, 
 it would be thought I had omitted the explication of 
 the majority of the objects that are in nature. 
 194 
 
PART IV. 195 
 
 CLXXXIX. What perception (sensus) is, and how 
 we perceive. 
 
 We must know, therefore, that although the human 
 soul is united to the whole body, it has, nevertheless, 
 its principal seat in the brain, where alone it not only 
 understands and imagines, but also perceives ; and this 
 by the medium of the nerves, which are extended like 
 threads from the brain to all the other members, with 
 which they are so connected that we can hardly touch 
 any one of them without moving the extremities of 
 some of the nerves spread over it; and this motion 
 passes to the other extremities of those nerves which 
 are collected in the brain round the seat of the soul,* 
 as I have already explained with sufficient minuteness 
 in the fourth chapter of the Dioptrics. But the move- 
 ments which are thus excited in the brain by the nerves 
 variously affect the soul or mind, which is intimately 
 conjoined with the brain, according to the diversity of 
 the motions themselves. And the diverse affections of 
 the mind or thoughts that immediately arise from these 
 motions, are called perceptions of the senses (sensuum 
 perceptiones), or, as we commonly speak, sensations 
 (sensus) . 
 
 CXC. Of the distinction of the senses ; and, first, of 
 the internal, that is, of the affections of the mind 
 (passions), and the natural appetites. 
 
 The varieties of these sensations depend, firstly, on 
 the diversity of the nerves themselves, and, secondly, 
 of the movements that are made in each nerve. We 
 have not, however, as many different senses as there 
 are nerves. We can distinguish but seven principal 
 
 * " common sense." — French. 
 
iç6 THE PRINCIPLES OF PHILOSOPHY. 
 
 classes of nerves, of which two belong to the internal, 
 and the other five to the external senses. The nerves 
 which extend to the stomach, the oesophagus, the 
 fauces, and the other internal parts that are subservient 
 to our natural wants, constitute one of our internal 
 senses. This is called the natural appetite (appetitus 
 naturalis). The other internal sense, which embraces 
 all the emotions (commotiones) of the mind or pas- 
 sions, and affections, as joy, sadness, love, hate, and 
 the like, depends upon the nerves which extend to the 
 heart and the parts about the heart, and are exceed- 
 ingly small ; for, by way of example, when the blood 
 happens to be pure and well tempered, so that it di- 
 lates in the heart more readily and strongly than usual, 
 this so enlarges and moves the small nerves scattered 
 around the orifices, that there is thence a correspond- 
 ing movement in the brain, which affects the mind' 
 with a certain natural feeling of joy; and as often as 
 these same nerves are moved in the same way, al- 
 though this is by other causes, they excite in our mind 
 the same feeling (sensus, sentiment). Thus, the im- 
 agination of the enjoyment of a good does not contain 
 in itself the feeling of joy, but it causes the animal 
 spirits to pass from the brain to the muscles in which 
 these nerves are inserted ; and thus dilating the orifices 
 ôf the heart, it also causes these small nerves to move 
 in the way appointed by nature to afford the sensation 
 of joy. Thus, when we receive news, the mind first 
 of all judges of it, and if the news be good, it rejoices 
 with that intellectual joy (gaudium intellectuale) 
 which is independent of any emotion (commotio) of 
 the body, and which the Stoics did not deny to their 
 wise man [although they supposed him exempt from 
 
PART IV. 197 
 
 all passion]. But as soon as this joy passes from the 
 understanding to the imagination, the spirits flow from 
 the brain to the muscles that are about the heart, and 
 there excite the motion of the small nerves, by means 
 of which another motion is caused in the brain, which 
 affects the mind with the sensation of animal joy 
 (laetitia animalis). On the same principle, when the 
 blood is so thick that it flows but sparingly into the 
 ventricles of the heart, and is not there sufficiently di- 
 lated, it excites in the same nerves a motion quite dif- 
 ferent from the preceding, which, communicated to the 
 brain, gives to the mind the sensation of sadness, al- 
 though the mind itself is perhaps ignorant of the cause 
 of its sadness. And all the other causes which move 
 these nerves in the same way may also give to the 
 mind the same sensation. But the other movements 
 of the same nerves produce other effects, as the feel- 
 ings of love, hate, fear, anger, etc., as far as they are 
 merely affections or passions of the mind; in other 
 words, as far as they are confused thoughts which the 
 mind has not from itself alone, but from its being 
 closely joined to the body, from which it receives im- 
 pressions ; for there is the widest difference between 
 these passions and the distinct thoughts which we have 
 of what ought to be loved, or chosen, or shunned, etc., 
 [although these are often enough found together]. 
 The natural appetites, as hunger, thirst, and the others, 
 are likewise sensations excited in the mind by means 
 of the nerves of the stomach, fauces, and other parts, 
 and are entirely different from the will which we have 
 to eat, drink, [and to do all that which we think proper 
 for the conservation of our body] ; but, because this 
 
198 THE PRINCIPLES OF PHILOSOPHY. 
 
 will or appetition almost always accompanies them, 
 they are therefore named appetites. 
 
 CXCI. Of the external senses ; and first of touch. 
 
 We commonly reckon the external senses five in 
 number, because there are as many different kinds of 
 objects which move the nerves and their organs, and 
 an equal number of kinds of confused thoughts ex- 
 cited in the soul by these emotions. In the first place, 
 the nerves terminating in the skin of the whole body 
 can be touched through this medium by any terrene 
 objects whatever, and moved by these wholes, in one 
 way by their hardness, in another by their gravity, in 
 a third by their heat, in a fourth by their humidity, 
 etc. — and in as many diverse modes as they are either 
 moved or hindered from their ordinary motion, to that 
 extent are diverse sensations excited in the mind, from 
 which a corresponding number of tactile qualities de- 
 rive their appellations. Besides this, when these 
 nerves are moved a little more powerfully than usual, 
 but not nevertheless to the degree by which our body 
 is in any way hurt, there thus arises a sensation of titil- 
 lation, which is naturally agreeable to the mind, be- 
 cause it testifies to it of the powers of the body with 
 which it is joined, [in that the latter can suffer the ac- 
 tion causing this titillation, without being hurt]. But 
 if this action be strong enough to hurt our body in any 
 way, this gives to our mind the sensation of pain. 
 And we thus see why corporeal pleasure and pain, al- 
 though sensations of quite an opposite character, arise 
 nevertheless from causes nearly alike. 
 
 CXCII. Of taste. 
 
 In the second place, the other nerves scattered over 
 the tongue and the parts in its vicinity are diversely 
 
PART IV. 199 
 
 moved by the particles of the same bodies, separated 
 from each other and floating in the saliva in the 
 mouth, and thus cause sensations of diverse tastes ac- 
 cording to the diversity of figure in these particles.* 
 
 CXCIII. Of smell. 
 
 Thirdly, two nerves also or appendages of the brain, 
 for they do not go beyond the limits of the skull, are 
 moved by the particles of terrestrial bodies, separated 
 and flying in the air, not indeed by all particles indif- 
 ferently, but by those only that are sufficiently subtle 
 and penetrating to enter the pores of the bone we call 
 the spongy, when drawn into the nostrils, and thus to 
 reach the nerves. From the different motions of these 
 particles arise the sensations of the different smells. 
 
 CXCIV. Of hearing. 
 
 Fourthly, there are two nerves within the ears, so 
 attached to three small bones that are mutually sus- 
 taining, and the first of which rests on the small mem- 
 brane that covers the cavity we call the tympanum of 
 the ear, that all the diverse vibrations which the sur- 
 rounding air communicates to this membrane are 
 transmitted to the mind by these nerves, and these vi- 
 brations give rise, according to their diversity, to the 
 sensations of the different sounds. 
 
 CXCV. Of sight. 
 
 Finally, the extremities of the optic nerves, compos- 
 ing the coat in the eyes called the retina, are not moved 
 by the air nor by any terrestrial object, but only by the 
 globules of the second element, 10 whence we have the 
 sense of light and colours : as I have already at suffi- 
 
 * In the French this section begins, "Taste, after touch the 
 grossest of the senses," etc. 
 
200 THE PRINCIPLES OF PHILOSOPHY. 
 
 cient length explained in the Dioptrics and treatise of 
 Meteors.* 
 
 CXCVI. That the soul perceives only in so far as it 
 is in the brain. 
 
 It is clearly established, however, that the soul does 
 not perceive in so far as it is in each member of the 
 body, but only in so far as it is in the brain, where 
 the nerves by their movements convey to it the diverse 
 actions of the external objects that touch the parts 
 of the body in which they are inserted. For, in the 
 first place, there are various maladies, which, though 
 they affect the brain alone, yet bring disorder upon, 
 or deprive us altogether of the use of, our senses, just 
 as sleep, which affects the brain only, and yet takes 
 from us daily during a great part of our time the fac- 
 ulty of perception, which afterwards in our waking 
 state is restored to us. The second proof is, that 
 though there be no disease in the brain, [or in the 
 members in which the organs of the external senses 
 are], it is nevertheless sufficient to take away sensa- 
 tion from the part of the body where the nerves ter- 
 minate, if only the movement of one of the nerves that 
 extend from the brain to these members be obstructed 
 in any part of the distance that is between the two. 
 And the last proof is, that we sometimes feel pain as 
 if in certain of our members, the cause of which, how- 
 ever, is not in these members where it is felt, but some- 
 where nearer the brain, through which the nerves pass 
 that give to the mind the sensation of it. I could es- 
 tablish this fact by innumerable experiments; I will 
 
 * In the French this section begins, "Finally, sight is the 
 most subtle of all the senses," etc. 
 
PART IV. 201 
 
 here, however, merely refer to one of them. A girl 
 suffering from a bad ulcer in the hand, had her eyes 
 bandaged whenever the surgeon came to visit her, not 
 being able to bear the sight of the dressing of the 
 sore; and, the gangrene having spread, after the ex- 
 piry of a few days the arm was amputated from the 
 elbow [without the girl's knowledge] ; linen cloths tied 
 one above the other were substituted in place of the 
 part amputated, so that she remained for some time 
 without knowing that the operation had been per- 
 formed, and meanwhile she complained of feeling va- 
 rious pains, sometimes in one finger of the hand that 
 was cut off, and sometimes in another. The only ex- 
 planation of this is, that the nerves which before 
 stretched downwards from the brain to the hand, and 
 then terminated in the arm close to the elbow, were 
 there moved in the same way as they required to be 
 moved before in the hand for the purpose of impressing 
 on the mind residing in the brain the sensation of pain 
 in this or that finger. [And this clearly shows that 
 the pain of the hand is not felt by the mind in so far 
 as it is in the hand, but in so far as it is in the brain.] 
 
 CXCVII. That the nature of the mind is such that 
 from the motion alone of body the various sensations 
 can be excited in it. 
 
 In the next place, it can be proved that our mind 
 is of such a nature that the motions of the body alone 
 are sufficient to excite in it all sorts of thoughts, with- 
 out it being necessary that these should in any way re- 
 semble the motions which give rise to them, and es- 
 pecially that these motions can excite in it those con- 
 fused thoughts called sensations (sensus, sensationes) . 
 For we see that words, whether uttered by the voice or 
 
202 THE PRINCIPLES OF PHILOSOPHY. 
 
 merely written, excite in our minds all kinds of 
 thoughts and emotions. On the same paper, with the 
 same pen and ink, by merely moving the point of the 
 pen over the paper in a particular way, we can trace 
 letters that will raise in the minds of our readers the 
 thoughts of combats, tempests, or the furies, and the 
 passions of indignation and sorrow ; in place of which, 
 if the pen be moved in another way hardly different 
 from the former, this slight change will cause thoughts 
 widely different from the above, such as those of re- 
 pose, peace, pleasantness, and the quite opposite pas- 
 sions of love and joy. Some one will perhaps object 
 that writing and speech do not immediately excite in 
 the mind any passions, or imaginations of things dif- 
 ferent from the letters and sounds, but afford simply 
 the knowledge of these, on occasion of which the mind, 
 understanding the signification of the words, after- 
 wards excites in itself the imaginations and passions 
 that correspond to the words. But what will be said 
 of the sensations of pain and titillation? The motion 
 merely of a sword cutting a part of our skin causes 
 pain, [but does not on that account make us aware of 
 the motion or figure of the sword] . And it is certain 
 that this sensation of pain is not less different from the 
 motion that causes it, or from that of the part of our 
 body which the sword cuts, than are the sensations we 
 have of colour, sound, odour, or taste. On this ground 
 we may conclude that our mind is of such a nature that 
 the motions alone of certain bodies can also easily ex- 
 cite in it all the other sensations, as the motion of a 
 sword excites in it the sensation of pain. 
 
 CXCVIII. That by our senses we know nothing of 
 
PART IV. 203 
 
 external objects beyond their figure [or situation], 
 magnitude, and motion. 
 
 Besides, we observe no such difference between the 
 nerves as to lead us to judge that one set of them con- 
 vey to the brain from the organs of the external senses 
 anything different from another, or that anything at 
 all reaches the brain besides the local motion of the 
 nerves themselves. And we see that local motion alone 
 causes in us not only the sensation of titillation and of 
 pain, but also of light and sounds. For if we receive 
 a blow on the eye of sufficient force to cause the vibra- 
 tion of the stroke to reach the retina, we see numerous 
 sparks of fire, which, nevertheless, are not out of our 
 eye ; and when we stop our ear with our finger, we hear 
 a humming sound, the cause of which can only pro- 
 ceed from the agitation of the air that is shut up within 
 it. Finally, we frequently observe that heat [hardness, 
 weight], and the other sensible qualities, as far as they 
 are in objects, and also the forms of those bodies that 
 are purely material, as, for example, the forms of fire, 
 are produced in them by the motion of certain other 
 bodies, and that these in their turn likewise produce 
 other motions in other bodies. And we can easily con- 
 ceive how the motion of one body may be caused by 
 that of another, and diversified by the size, figure, and 
 situation of its parts, but we are wholly unable to con- 
 ceive how these same things (viz., size, figure, and 
 motion), can produce something else of a nature en- 
 tirely different from themselves, as, for example, those 
 substantial forms and real qualities which many philos- 
 ophers suppose to be in bodies ; nor likewise can we 
 conceive how these qualities or forms possess force to 
 cause motions in other bodies. But since we know, 
 
204 THE PRINCIPLES OF PHILOSOPHY. 
 
 from the nature of our soul, that the diverse motions 
 of body are sufficient to produce in it all the sensations 
 which it has, and since we learn from experience that 
 several of its sensations are in reality caused by such 
 motions, while we do not discover that anything be- 
 sides these motions ever passes from the organs of the 
 external senses to the brain, we have reason to conclude 
 that we in no way likewise apprehend that in external 
 objects, which we call light, colour, smell, taste, sound, 
 heat or cold, and the other tactile qualities, or that 
 which we call their substantial forms, unless as the va- 
 rious dispositions of these objects which have the 
 power of moving our nerves in various ways.* 
 
 CXCIX. That there is no phenomenon of nature 
 whose explanation has been omitted in this treatise. 
 
 And thus it may be gathered, from an enumeration 
 that is easily made, that there is no phenomenon of na- 
 ture whose explanation has been omitted in this 
 treatise; for beyond what is perceived by the senses, 
 there is nothing that can be considered a phenomenon 
 of nature. But leaving out of account motion, magni- 
 tude, figure, [and the situation of the parts of each 
 body], which I have explained as they exist in body, 
 we perceive nothing out of us by our senses except 
 light, colours, smells, tastes, sounds, and the tactile 
 qualities ; and these I have recently shown to be noth- 
 ing more, at least so far as they are known to us, than 
 certain dispositions of the objects, consisting in magni- 
 tude, figure, and motion. 
 
 CC. That this treatise contains no principles which 
 
 * " the diverse figures, situations, magnitudes, and motions 
 of their parts." — French. 
 
PART IV. 305 
 
 are not universally received; and that this philosophy 
 is not new, but of all others the most ancient and com- 
 mon. 
 
 But I am desirous also that it should be observed 
 that, though I have here endeavoured to give an ex- 
 planation of the whole nature of material things, I 
 have nevertheless made use of no principle which was 
 not received and approved by Aristotle, and by the 
 other philosophers of all ages ; so that this philosophy, 
 so far from being new, is of all others the most ancient 
 and common : for I have in truth merely considered 
 the figure, motion, and magnitude of bodies, and 
 examined what must follow from their mutual con- 
 course on the principles of mechanics, which are con- 
 firmed by certain and daily experience. But no one 
 ever doubted that bodies are moved, and that they are 
 of various sizes and figures, according to the diversity 
 of which their motions also vary, and that from mutual 
 collision those somewhat greater than others are di- 
 vided into many smaller, and thus change figure. We 
 have experience of the truth of this, not merely by a 
 single sense, but by several, as touch, sight, and hear- 
 ing: we also distinctly imagine and understand it. 
 This cannot be said of any of the other things that fall 
 under our senses, as colours, sounds, and the like ; for 
 each of these affects but one of our senses, and merely 
 impresses upon our imagination a confused image of 
 itself, affording our understanding no distinct knowl- 
 edge of what it is. 
 
 CCI. That sensible bodies are composed of insensi- 
 ble particles. 
 
 But I allow many particles in each body that are 
 perceived by none of our senses, and this will not per- 
 
206 THE PRINCIPLES OF PHILOSOPHY. 
 
 haps be approved of by those who take the senses for 
 the measure of the knowable. [We greatly wrong 
 human reason, however, as appears to me, if we sup- 
 pose that it does not go beyond the eye-sight] ; for no 
 one can doubt that there are bodies so small as not to 
 be perceptible by any of our senses, provided he only 
 consider what is each moment added to those bodies 
 that are being increased little by little, and what is 
 taken from those that are diminished in the same way. 
 A tree increases daily, and it is impossible to conceive 
 how it becomes greater than it was before, unless we at 
 the same time conceive that some body is added to it. 
 But who ever observed by the senses those small bodies 
 that are in one day added to a tree while growing? 
 Among the philosophers at least, those who hold that 
 quantity is indefinitely divisible, ought to admit that in 
 the division the parts may become so small as to be 
 wholly imperceptible. And indeed it ought not to be 
 a matter of surprise, that we are unable to perceive 
 very minute bodies ; for the nerves that must be moved 
 by objects to cause perception are not themselves very 
 minute, but are like small cords, being composed of a 
 quantity of smaller fibres, and thus the most minute 
 bodies are not capable of moving them. Nor do I think 
 that any one who makes use of his reason will deny 
 that we philosophize with much greater truth when 
 we judge of what takes place in those small bodies 
 which are imperceptible from their minuteness only, 
 after the analogy of what we see occurring in those we 
 do perceive, [and in this way explain all that is in na- 
 ture, as I have essayed to do in this treatise], than 
 when we give an explanation of the same things by in- 
 venting I know not what novelties, that have no rela- 
 
PART IV, 207 
 
 tion to the things we actually perceive, [as first matter, 
 substantial forms, and all that grand array of qualities 
 which many are in the habit of supposing, each of 
 which is more difficult to comprehend than all that is 
 professed to be explained by means of them]. 
 
 CCII. That the philosophy of Democritus is not 
 less different from ours than from the common.* 
 
 But it may be said that Democritus also supposed 
 certain corpuscles that were of various figures, sizes, 
 and motions, from the heaping together and mutual 
 concourse of which all sensible bodies arose; and, 
 nevertheless, his mode of philosophizing is commonly 
 rejected by all. To this I reply that the philosophy of 
 Democritus was never rejected by any one, because he 
 allowed the existence of bodies smaller than those we 
 perceive, and attributed to them diverse sizes, figures, 
 and motions, for no one can doubt that there are in 
 reality such, as we have already shown ; but it was re- 
 jected, in the first place, because he supposed that these 
 corpuscles were indivisible, on which ground I also re- 
 ject it; in the second place, because he imagined 
 there was a vacuum about them, which I show to be im- 
 possible ; thirdly, because he attributed gravity to these 
 bodies, of which I deny the existence in any body, in 
 so far as a body is considered by itself, because it is a 
 quality that depends on the relations of situation and 
 motion which several bodies bear to each other; and, 
 finally, because he has not explained in particular how 
 all things arose from the concourse of corpuscles alone, 
 or, if he gave this explanation with regard to a few of 
 them, his whole reasoning was far from being coherent, 
 
 * " that of Aristotle or the others." — French. 
 
208 THE PRINCIPLES OF PHILOSOPHY. 
 
 [or such as would warrant us in extending the same 
 explanation to the whole of nature]. This, at least, is 
 the verdict we must give regarding his philosophy, if 
 we may judge of his opinions from what has been 
 handed down to us in writing. I leave it to others to 
 determine whether the philosophy I profess possesses 
 a valid coherency, [and whether on its principles we 
 can make the requisite number of deductions ; and, in- 
 asmuch as the consideration of figure, magnitude, and 
 motion has been admitted by Aristotle and by all the 
 others, as well as by Democritus, and since I reject all 
 that the latter has supposed, with this single exception, 
 while I reject generally all that has been supposed by 
 the others, it is plain that this mode of philosophizing 
 has no more affinity with that of Democritus than of 
 any other particular sect]. 
 
 CCIII. How we may arrive at the knowledge of the 
 figures, [magnitudes], and motions of the insensible 
 particles of bodies. 
 
 But, since I assign determinate figures, magnitudes, 
 and motions to the insensible particles of bodies, as if 
 I had seen them, whereas I admit that they do not fall 
 under the senses, some one will perhaps demand how I 
 have come by my knowledge of them. [To this I re- 
 ply, that I first considered in general all the clear and 
 distinct notions of material things that are to be found 
 in our understanding, and that, finding no others ex- 
 cept those of figures, magnitudes, and motions, and of 
 the rules according to which these three things can be 
 diversified by each other, which rules are the principles 
 of geometry and mechanics, I judged that all the 
 knowledge man can have of nature must of necessity 
 be drawn from this source; because all the other no- 
 
PART IV. 209 
 
 tions we have of sensible things, as confused and ob- 
 scure, can be of no avail in affording us the knowl- 
 edge of anything out of ourselves, but must serve 
 rather to impede it] . Thereupon, taking as my ground 
 of inference the simplest and best known of the princi- 
 ples that have been implanted in our minds by nature, 
 I considered the chief differences that could possibly 
 subsist between the magnitudes, and figures, and situa- 
 tions of bodies insensible on account of their smallness 
 alone, and what sensible effects could be produced by 
 their various modes of coming into contact ; and after- 
 wards, when I found like effects in the bodies that we 
 perceive by our senses, I judged that they could have 
 been thus produced, especially since no other mode of 
 explaining them could be devised. And in this matter 
 the example of several bodies made by art was of great 
 service to me : for I recognize no difference between 
 these and natural bodies beyond this, that the effects of 
 machines depend for the most part on the agency of 
 certain instruments, which, as they must bear some 
 proportion to the hands of those who make them, are 
 always so large that their figures and motions can be 
 seen; in place of which, the effects of natural bodies 
 almost always depend upon certain organs so minute 
 as to escape our senses. And it is certain that all the 
 rules of mechanics belong also to physics, of which it 
 is a part or species, [so that all that is artificial is withal 
 natural] : for it is not less natural for a clock, made of 
 the requisite number of wheels, to mark the hours, than 
 for a tree, which has sprung from this or that seed, to 
 produce the fruit peculiar to it. Accordingly, just as 
 those who are familiar with automata, when they are 
 
2io THE PRINCIPLES OF PHILOSOPHY. 
 
 informed of the use of a machine, and see some of its 
 parts, easily infer from these the way in which the 
 others, that are not seen by them, are made; so from 
 considering the sensible effects and parts of natural 
 bodies, I have essayed to determine the character of 
 their causes and insensible parts. 
 
 CCIV. That, touching the things which our senses 
 do not perceive, it is sufficient to explain how they can 
 be, [and that this is all that Aristotle has essayed]. 
 
 But here some one will perhaps reply, that although 
 I have supposed causes which could produce all natural 
 objects, we ought not on this account to conclude that 
 they were produced by these causes; for, just as the 
 same artisan can make two clocks, which, though they 
 both equally well indicate the time, and are not differ- 
 ent in outward appearance, have nevertheless nothing 
 resembling in the composition of their wheels ; so 
 doubtless the Supreme Maker of things has an infinity 
 of diverse means at his disposal, by each of which he 
 could have made all the things of this world to appear 
 as we see them, without it being possible for the human 
 mind to know which of all these means he chose to em- 
 ploy. I most freely concede this ; and I believe that I 
 have done all that was required, if the causes I have as- 
 signed are such that their effects accurately correspond 
 to all the phenomena of nature, without determining 
 whether it is by these or by others that they are ac- 
 tually produced. And it will be sufficient for the use 
 of life to know the causes thus imagined, for medicine, 
 mechanics, and in general all the arts to which the 
 knowledge of physics is of service, have for their end 
 only those effects that are sensible, and that are accord- 
 
PART IV. 2ii 
 
 ingly to be reckoned among the phenomena of nature.* 
 And lest it should be supposed that Aristotle did, or 
 professed to do, anything more than this, it ought to be 
 remembered that he himself expressly says, at the com- 
 mencement of the seventh chapter of the first book of 
 the Meteorologies, that, with regard to things which 
 are not manifest to the senses, he thinks to adduce 
 sufficient reasons and demonstrations of them, if he 
 only shows that they may be such as he explains 
 them.f 
 
 CCV. That nevertheless there is a moral certainty 
 that all the things of this world are such as has been 
 here shown they may be. 
 
 But nevertheless, that I may not wrong the truth 
 by supposing it less certain than it is, I will here dis- 
 tinguish two kinds of certitude. The first is called 
 moral, that is, a certainty sufficient for the conduct of 
 life, though, if we look to the absolute power of God, 
 what is morally certain may be false. [Thus, those 
 who never visited Rome do not doubt that it is a city 
 of Italy, though it might be that all from whom they 
 got their information were deceived]. Again, if any 
 one, wishing to decipher a letter written in Latin char- 
 acters that are not placed in regular order, bethinks 
 
 * " have for their end only to apply certain sensible bodies 
 to each other in such a way that, in the course of natural 
 causes, certain sensible effects may be produced ; and we will 
 be able to accomplish this quite as well by considering the 
 series of certain causes thus imagined, although false, as if 
 they were the true, since this series is supposed similar as far 
 as regards sensible effects." — French. 
 
 \ 'Enel ôè irspî tûv àfavûv tt) aladrjaei vofii^ofiev licavûç àKoôeôsïxdai 
 Kara rbv Myov, èàv elç to âvvarov àvayâywjuev, è/c re tûv vvv <j>aivo/uévuv 
 vnolâfioi tcç âv ùôe wepî tovtuv fiâXidTa av/u(3aivecv. Merewp a. 7. — T. 
 
212 THE PRINCIPLES OF PHILOSOPHY. 
 
 himself of reading a B wherever an A is found, and a 
 C wherever there is a B, and thus of substituting in 
 place of each letter the one which follows it in the or- 
 der of the alphabet, and if by this means he finds that 
 there are certain Latin words composed of these, he 
 will not doubt that the true meaning of the writing is 
 contained in these words, although he may discover 
 this only by conjecture, and although it is possible that 
 the writer of it did not arrange the letters on this 
 principle of alphabetical order, but on some other, and 
 thus concealed another meaning in it : for this is so im- 
 probable [especially when the cipher contains a num- 
 ber of words] as to seem incredible. But they who ob- 
 serve how many things regarding the magnet, fire, and 
 the fabric of the whole world, are here deduced from a 
 very small number of principles, though they deemed 
 that I had taken them up at random and without 
 grounds, will yet perhaps acknowledge that it could 
 hardly happen that so many things should cohere if 
 these principles were false. 
 
 CCVI. That we possess even more than a moral 
 certainty of it. 
 
 Besides, there are some, even among natural, things 
 which we judge to be absolutely certain. [Absolute 
 certainty arises when we judge that it is impossible a 
 thing can be otherwise than as we think it]. This cer- 
 tainty is founded on the metaphysical ground, that, as 
 God is supremely good and the source of all truth, the 
 faculty of distinguishing truth from error which he 
 gave us, cannot be fallacious so long as we use it 
 aright, and distinctly perceive anything by it. Of this 
 character are the demonstrations of mathematics, the 
 knowledge that material things exist, and the clear tea- 
 
PART IV. 213 
 
 sonings that are formed regarding them. The results 
 I have given in this treatise will perhaps be admitted 
 to a place in the class of truths that are absolutely cer- 
 tain, if it be considered that they are deduced in a con- 
 tinuous series from the first and most elementary prin- 
 ciples of human knowledge; especially if it be suffi- 
 ciently understood that we can perceive no external ob- 
 jects unless some local motion be caused by them in our 
 nerves, and that such motion cannot be caused by the 
 fixed stars, owing to their great distance from us, un- 
 less a motion be also produced in them and in the whole 
 heavens lying between them and us : for these points 
 being admitted, all the others, at least the more general 
 doctrines which I have advanced regarding the world 
 or earth [e. g., the fluidity of the heavens, Part III., §. 
 XLVL], will appear to be almost the only possible ex- 
 planations of the phenomena they present. 
 
 CCVII. That, however, I submit all my opinions 
 to the authority of the church. 
 
 Nevertheless, lest I should presume too far, I affirm 
 nothing, but submit all these my opinions to the 
 authority of the church and the judgment of the more 
 sage ; and I desire no one to believe anything I may 
 have said, unless he is constrained to admit it by the 
 force and evidence of reason. 
 
APPENDIX. 
 
 (From the Reply to the Second Objections — Latin, 1670. pp. 
 85-91. French, Gamier. Tom. II., pp. 74-84.) 
 
 REASONS WHICH ESTABLISH THE EXISTENCE OF GOD, 
 AND THE DISTINCTION BETWEEN THE MIND AND 
 BODY OF MAN, DISPOSED IN GEOMETRICAL ORDER. 
 DEFINITIONS. 
 
 I. By the term thought (cogitatio, pensée), I comprehend 
 all that is in us, so that we are immediately conscious of it. 
 Thus, all the operations of the will, intellect, imagination, and 
 senses, are thoughts. But I have used the word immediately 
 expressly to exclude whatever follows or depends upon our 
 thoughts ; for example, voluntary motion has, in truth, thought 
 for its source (principle), but yet it is not itself thought. 
 [Thus, walking is not a thought, but the perception or knowl- 
 edge we have of our walking is.] 
 
 II. By the word idea I understand that form of any thought, 
 by the immediate perception of which I am conscious of that 
 same thought; so that I can express nothing in words, when 
 I understand what I say, without making it certain, by this 
 alone, that I possess the idea of the thing that is signified by 
 these words. And thus I give the appellation idea not to the 
 images alone that are depicted in the phantasy; on the con- 
 trary, I do not here apply this name to them, in so far as 
 they are in the corporeal phantasy, that is to say, in so far 
 as they are depicted in certain parts of the brain, but only in 
 so far as they inform the mind itself, when turned towards 
 that part of the brain. 
 
 III. By the objective reality of an idea I understand the 
 entity or being of the thing represented by the idea, in so far 
 as this entity is in the idea ; and, in the same manner, it may 
 be called either an objective perfection, or objective artifice, 
 
 215 
 
2i6 APPENDIX. 
 
 etc. (artiûcium objectivum). For all that we conceive to be 
 in the objects of the ideas is objectively [or by representation] 
 in the ideas themselves. 
 
 IV. The same things are said to be formally in the objects 
 of the ideas when they are in them such as we conceive them ; 
 and they are said to be in the objects eminently when they are 
 not indeed such as we conceive them, but are so great that 
 they can supply this defect by their excellence. 
 
 V. Everything in which there immediately resides, as in a 
 subject, or by which there exists any object we perceive, that 
 is, any property, or quality, or attribute of which we have 
 in us a real idea, is called substance. For we have no other 
 idea of substance, accurately taken, except that it is a thing 
 in which exists formally or eminently this property or quality 
 which we perceive, or which is objectively in some one of our 
 ideas, since we are taught by the natural light that nothing can 
 have no real attribute. 
 
 VI. The substance in which thought immediately resides 
 is here called mind (mens, esprit). I here speak, however, 
 of mens rather than of anima, for the latter is equivocal, being 
 frequently applied to denote a corporeal object. 
 
 VII. The substance which is the immediate subject of local 
 extension, and of the accidents that presuppose this exten- 
 sion, as figure, situation, local motion, etc., is called body. 
 But whether the substance which is called mind be the same 
 with that which is called body, or whether they are two di- 
 verse substances, is a question to be hereafter considered. 
 
 VIII. The substance which we understand to be supremely 
 perfect, and in which we conceive nothing that involves any 
 defect, or limitation of perfection, is called God. 
 
 IX. When we say that some attribute is contained in the 
 nature or concept of a thing, this is the same as if we said 
 that the attribute is true of the thing, or that it may be af- 
 firmed of the thing itself. 
 
 X. Two substances are said to be really distinct, when each 
 of them may exist without the other. 
 
 POSTULATES. 
 
 1st. I request that my readers consider how feeble are the 
 reasons that have hitherto led them to repose faith in their 
 
APPENDIX. 217 
 
 senses, and how uncertain are all the judgments which they 
 afterwards founded on them; and that they will revolve this 
 consideration in their mind so long and so frequently, that, 
 in fine, they may acquire the habit of no longer trusting so 
 confidently in their senses ; for I hold that this is necessary to 
 render one capable of apprehending metaphysical truths. 
 
 2d. That they consider their own mind, and all those of its 
 attributes of which they shall find they cannot doubt, though 
 they may have supposed that all they ever received by the 
 senses was entirely false, and that they do not leave off con- 
 sidering it until they have acquired the habit of conceiving 
 it distinctly, and of believing that it is more easy to know than 
 any corporeal object. 
 
 3d. That they diligently examine such propositions as are 
 self-evident, which they will find within themselves, as the 
 following: — That the same thing cannot at once be and not 
 be ; that nothing cannot be the efficient cause of anything, and 
 the like; — and thus exercise that clearness of understanding 
 that has been given them by nature, but which the perceptions 
 of the senses are wont greatly to disturb and obscure — exercise 
 it, I say, pure and delivered from the objects of sense; for in 
 this way the truth of the following axioms will appear very 
 evident to them. 
 
 4th. That they examine the ideas of those natures which con- 
 tain in them an assemblage of several attributes, such as the na- 
 ture of the triangle, that of the square, or of some other figure ; 
 as also the nature of mind, the nature of body, and above all 
 that of God, or of a being supremely perfect. And I request 
 them tq observe that it may with truth be affirmed that all 
 these things are in objects, which we clearly conceive to be 
 contained in them : for example, because that, in the nature of 
 the rectilineal triangle, this property is found contained — viz., 
 that its three angles are equal to two right angles, and that in 
 the nature of body or of an extended thing, divisibility is com- 
 prised (for we do not conceive any extended thing so small 
 that we cannot divide it, at least in thought)— it is true that 
 the three angles of a rectilineal triangle are equal to two right 
 angles, and that all body is divisible. 
 
 5th. That they dwell much and long on the contemplation 
 
2i8 APPENDIX. 
 
 of the supremely perfect Being, and, among other things, con- 
 sider that in the ideas of all other natures, possible existence 
 is indeed contained, but that in the idea of God is contained 
 not only possible but absolutely necessary existence. For, 
 from this alone, and without any reasoning, they will discover 
 that God exists : and it will be no less evident in itself than 
 that two is an equal and three an unequal number, with other 
 truths of this sort. For there are certain truths that are thus 
 manifest to some without proof, which are not comprehended 
 by others without a process of reasoning. 
 
 6th. That carefully considering all the examples of clear 
 and distinct perception, and all of obscure and confused, of 
 which I spoke in my Meditations, they accustom themselves to 
 distinguish things that are clearly known from those that are 
 obscure, for this is better learnt by example than by rules; 
 and I think that I have there opened up, or at least in some 
 degree touched upon, all examples of this kind. 
 
 7th. That readers adverting to the circumstance that they 
 never discovered any falsity in things which they clearly con- 
 ceived, and that, on the contrary, they never found, unless by 
 chance, any truth in things which they conceived but obscurely, 
 consider it to be wholly irrational, if, on acount only of certain 
 prejudices of the senses, or hypotheses which contain what is 
 unknown, they call in doubt what is clearly and distinctly con- 
 ceived by the pure understanding; for they will thus readily 
 admit the following axioms to be true and indubitable, though 
 I confess that several of them might have been much better 
 unfolded, and ought rather to have been proposed as theorems 
 than as axioms, if I had desired to be more exact. 
 
 AXIOMS OR COMMON NOTIONS. 
 
 I. Nothing exists of which it cannot be inquired what is the 
 cause of its existing; for this can even be asked respecting 
 God; not that there is need of any cause in order to his ex- 
 istence, but because the very immensity of his nature is the 
 cause or reason why there is no need of any cause of his exisr 
 tence. 
 
 II. The present time is not dependent on that which im- 
 mediately preceded it; for this reason, there is not need of a 
 less cause for conserving a thing than for at first producing it. 
 
APPENDIX. 219 
 
 III. Any thing or any perfection of a thing actually existent 
 cannot have nothing, or a thing non-existent, for the cause of 
 its existence. 
 
 IV. All the reality or perfection which is in a thing is 
 found formally or eminently in its first and total cause. 
 
 V. Whence it follows likewise, that the objective reality of 
 our ideas requires a cause in which this same reality is con- 
 tained, not simply objectively, but formally or eminently. And 
 it is to be observed that this axiom must of necessity be ad- 
 mitted, as upon it alone depends the knowledge of all things, 
 whether sensible or insensible. For whence do we know, for 
 example, that the sky exists? Is it because we see it? But 
 this vision does not affect the mind unless in so far as it is 
 an idea, and an idea inhering in the mind itself, and not an 
 image depicted on the phantasy; and, by reason of this idea, 
 we cannot judge that the sky exists unless we suppose that 
 every idea must have a cause of its objective reality which 
 is really existent; and this cause we judge to be the sky it- 
 self, and so in the other instances. 
 
 VI. There are diverse degrees of reality, that is, of entity 
 [or perfection] : for substance has more reality than accident 
 or mode, and infinite substance than finite; it is for this rea- 
 son also that there is more objective reality in the idea of 
 substance than in that of accident, and in the idea of infinite 
 than in the idea of finite substance. 
 
 VII. The will of a thinking being is carried voluntarily and 
 freely, for that is of the es.sence of will, but nevertheless in- 
 fallibly, to the good that is clearly known to it; and, there- 
 fore, if it discover any perfections which it does not possess, 
 it will instantly confer them on itself if they are in its power ; 
 [for it will perceive that to possess them is a greater good than 
 to want them.] 
 
 VIII. That which can accomplish the greater or more diffi- 
 cult, can also accomplish the less or the more easy. 
 
 IX. It is a greater and more difficult thing to create or 
 conserve a substance than to create or conserve its attributes 
 or properties; but this creation of a thing is not greater or 
 more difficult than its conservation, as has been already said. 
 
 X. In the idea or concept of a thing existence is contained, 
 
220 APPENDIX. 
 
 because we- are unable to conceive anything unless under the 
 form of a thing which exists ; but with this difference that, in 
 the concept of a limited thing, possible or contingent existence 
 is alone contained, and in the concept of a being sovereignly- 
 perfect, perfect and necessary existence is comprised. 
 
 PROPOSITION I. 
 
 The existence of God is known from the consideration of 
 his nature alone. 
 
 DEMONSTRATION. 
 
 To say that an attribute is contained in the nature or in the 
 concept of a thing, is the same as to say that this attribute 
 is true of this thing, and that it may be affirmed to be in it. 
 (Definition IX.) 
 
 But necessary existence is contained in the nature or in the 
 concept of God (by Axiom X.) 
 
 Hence it may with truth be said that necessary existence is 
 in God, or that God exists. 
 
 And this syllogism is the same as that of which I made use 
 in my reply to the sixth article of these objections; and its 
 conclusion may be known without proof by those who are free 
 from all prejudice, as has been said in Postulate V. But 
 because it is not so easy to reach so great perspicacity of 
 mind, we shall essay to establish the same thing by other 
 modes. 
 
 PROPOSITION II. 
 
 The existence of God is demonstrated, a posteriori, from 
 this alone, that his idea is in us. 
 
 DEMONSTRATION. 
 
 The objective reality of each of our ideas requires a cause 
 in which this same reality is contained, not simply objectively, 
 but formally or eminently (by Axiom V.) 
 
 But we have in us the idea of God (by Definitions II and 
 VIII), and of this idea the objective reality is not contained 
 in us, either formally or eminently (by Axiom VI), nor can 
 it be contained in any other except in God himself (by Defi- 
 nition VIII). 
 
 Therefore this idea of God which is in us demands God for 
 its cause, and consequently God exists (by Axiom III). 
 
APPENDIX. 
 
 PROPOSITION III. 
 
 The existence of God is also demonstrated from this, that 
 we ourselves, who possess the idea of him, exist. 
 
 DEMONSTRATION. 
 
 If I possessed the power of conserving myself, I should 
 likewise have the power of conferring, a fortiori, on myself, 
 all the perfections that are awanting to me (by Axioms VIII 
 and IX), for these perfections are only attributes of substance 
 whereas I myself am a substance. 
 
 But I have not the power of conferring on myself these 
 perfections, for otherwise I should already possess them (by 
 Axiom VII). 
 
 Hence, I have not the power of self-conservation. 
 
 Further, I cannot exist without being conserved, so long as 
 I exist, either by myself, supposing I possess the power, or 
 by another who has this power (by Axioms I and II). 
 
 But I exist, and yet I have not the power of self-conserva- 
 tion, as I have recently proved. Hence I am conserved by 
 another. 
 
 Further, that by which I am conserved has in itself formally 
 or eminently all that is in me (by Axiom IV). 
 
 But I have in me the perception of many perfections that are 
 awanting to me, and that also of the idea of God (by Defini- 
 tions II and VIII). Hence the perception of these same per- 
 fections is in him by whom I am conserved. 
 
 Finally, that same being by whom I am conserved cannot 
 have the perception of any perfections that are awanting to 
 him, that is to say, which he has not in himself formally or 
 eminently (by Axiom VII) ; for having the power of con- 
 serving me, as has been recently said, he should have, a for- 
 tiori, the power of conferring these perfections on himself, if 
 they were awanting to him (by Axioms VIII and IX). 
 
 But he has the perception of all the perfections which I 
 discover to be wanting to me, and which I conceive can be in 
 God alone, as I recently proved: 
 
 Hence he has all these in himself, formally or eminently, 
 and thus he is God. 
 
APPENDIX. 
 
 COROLLARY. 
 
 God has created the sky and the earth and all that is therein 
 contained; and besides this he can make all the things which 
 we clearly conceive in the manner in which we conceive them. 
 
 DEMONSTRATION. 
 
 All these things clearly follow from the preceding proposi- 
 tion. For in it we have proved the existence of God, from 
 its being necessary that some one should exist in whom are 
 contained formally or eminently all the perfections of which 
 there is in us any idea. 
 
 But we have in us the idea of a power so great, that by the 
 being alone in whom it resides, the sky and the earth, etc., 
 must have been created, and also that by the same being all the 
 other things which we conceive as possible can be produced. 
 
 Hence, in proving the existence of God, we have also proved 
 with it all these things. 
 
 PROPOSITION IV. 
 
 The mind and body are really distinct. 
 
 DEMONSTRATION. 
 
 All that we clearly conceive can be made by God in the 
 manner in which we conceive it (by foregoing Corollary). 
 
 But we clearly conceive mind, that is, a substance which 
 thinks, without body, that is to say, without an extended sub- 
 stance (by Postulate II) ; and, on the other hand, we as 
 clearly conceive body without mind (as every one admits). 
 
 Hence, at least, by the omnipotence of God, the mind can 
 exist without the body, and the body without the mind. 
 
 Now, substances which can exist independently of each 
 other, are really distinct (by Definition X). 
 
 But the mind and the body are substances (by Definitions 
 V, VI, and VII), which can exist independently of each other, 
 as I have recently proved : 
 
 Hence the mind and the body are really distinct. 
 
 And it must be observed that I have here made use of the 
 omnipotence of God in order to found my proof on it, not 
 that there is need of any extraordinary power in order to sep- 
 
APPENDIX. 223 
 
 arate the mind from the body, but for this reason, that, as I 
 have treated of God only in the foregoing propositions, I could 
 not draw my proof from any other source than from him: 
 and it matters very little by what power two things are sep- 
 arated in order to discover that they are really distinct. 
 
NOTES. 
 
 I. TO PERCEIVE — PERCEPTION — p. 10. 
 
 The term perception {perceptio) has a much wider significa- 
 tion in the writings of Descartes and the Cartesians than in 
 the literature of the schools of philosophy in our times. Per- 
 ception is, at present, used to denote the immediate knowledge 
 we obtain through sense, or even still further restricted to the 
 apprehension of what have been called the primary qualities 
 of matter; with the Cartesians, and the older philosophers 
 generally, the word is employed in the same sense in which 
 we use consciousness, to denote an act of mind by which we 
 merely apprehend or take note of the object of thought or 
 consciousness, considered as distinguished from any affirma- 
 tion or negation (judgment) regarding it. Accordingly, in 
 Cartesian literature perception is synonymous with cogtiition, 
 when, in the narrower sense of the term, it is said to consist 
 in the apprehension of a thing, or in the immediate conscious- 
 ness of that which is known, as opposed to judgment and rea- 
 soning. It thus includes both the representative knowledge of 
 imagination (and with the Cartesians, of sense), and the 
 mediate or representative knowledge given in a notion or con- 
 cept ; for we cannot, either in imagination or conception, rep- 
 resent without being conscious of the representation, i. e., 
 without perceiving or immediately apprehending it. Per- 
 cipere in Cartesian literature is thus, with greater or less 
 propriety, considered as equivalent to cognoscere, intelligere 
 (in the narrower sense of these terms), rem menti propositam 
 concipere, intueri; cogitatione sibi representare; rerum ideas 
 intueri; res per ideas videre ; rem per intellectus ideam intueri, 
 cernere; ret ideam in intellectu habere. Perceptio is properly 
 synonymous with perceptio simplex, apprehensio seu appre- 
 hensio simplex (q. prehensio objecti ab intellectu) intellectio 
 224 
 
NOTES. 225 
 
 simplex, visio simplex, cognitio, and less properly with con- 
 ceptus, notio, idea rei. In logical language, the character of 
 perception is expressed by saying that the act has for its ob- 
 ject a thema simplex, i. e., in the language of Descartes, either 
 substance or attribute, as opposed to the thema conjunctum 
 seu compositum, or notionum complexity per aMrmationem 
 et negationem, i. e., enunciatio, or, in the language of Des- 
 cartes, a truth. — Prin. of Phil., P. I., § 48. Claubergius, Op. 
 P. I., pp. 334, 503. (Ed. 1691.) Flenderus, Log. Cont. Claub. 
 111. §§ 1.5. (4th Ed.) 
 
 To illustrate more particularly the nature and sphere of per- 
 ception, as the term is used in the Cartesian school, it is neces- 
 sary to attend to the division of the phenomena of conscious- 
 ness, adopted by Descartes, and current among his followers. 
 Descartes divides all our thoughts (cogitationes) — and with 
 him thought is the general name for each mode or phaenome- 
 non of consciousness — into two grand classes, viz., the Ac- 
 tivities and Passivities of mind (actiones et passiones sive 
 affectus animac), the distinguishing element of these two 
 classes being, that in the former case the mind of itself de- 
 termines its own modification; in the latter it is determined to 
 it, by some action, to wit, foreign from the will. The first 
 class embraces all the acts of the Will, or the volitions, (voli- 
 tiones sive operationes voluntatis) , inasmuch as all such modi- 
 fications of mind are considered by him as determinable, and 
 actually determined, by the power of free choice or will, i. 
 e., by the mind itself; and under volition (i. e., to use the 
 language of his followers, latio quaedam animi tendens ad 
 objectum in idea propositum) he comprehends judgment and 
 will proper (velle et nolle), according as the object is re- 
 garded under the notions of the true and the false, or of the 
 good and the bad. To the second class he refers all the Cog- 
 nitive acts of the mind, considered merely as apprehensive of 
 their objects (perceptiones sive operationes intellectus) , inas- 
 much as our apprehensions are not made arbitrarily, or at the 
 pleasure of our will, but determined by their objects, and are 
 thus, in a sense, passions or passivities. In this way all the 
 acts, whether of sense, memory, imagination, or the pure in- 
 tellect, are but different modes of perceiving; for in each 
 
226 NOTES. 
 
 we only know as we are conscious of, or apprehend, the ob- 
 ject of the act. Further, as each mental modification has a 
 reality for us only in so far as we actually apprehend or are 
 conscious of it, it is plain that, in every actual mode of mind, 
 there is involved a consciousness, or, in the Cartesian lan- 
 guage, a perception; and thus we are said to perceive not only 
 when in sense we apprehend by idea or representation extension 
 or figure — the qualities of somewhat lying beyond ourselves, 
 or the representative object in imagination, but likewise when 
 we are conscious of the forth-putting of an act of will or of 
 being affected by joy or hope. More particularly as, according 
 to the Cartesian doctrine, the consciousness of a modification 
 of mind, a volition, for example, is, though in thought (ra- 
 tione) separable, not really distinct from this modification it- 
 self, all modes of mind whatsoever, as participating of con- 
 sciousness, are, in a sense, perceptions; for this implies nothing 
 more than that they exist in consciousness. In this sense 
 perception is not contrasted with, but comprehends volition, 
 though extending further. As some modifications of mind, 
 however, though only manifesting themselves through knowl- 
 edge, are yet not apprehension simply or even knowledge, but 
 to use his own phrase, have other forms, as volition, we may 
 consider them in reference to these other characters; and as, 
 on the Cartesian doctrine, these characters are negative of each 
 other, we thus obtain classes not only in opposition, but in 
 fundamental contrast. These distinguishing characteristics 
 are, as we have seen, the qualities of activity and of passivity, 
 which thus afford two grand divisions of the mental modifica- 
 tions, called respectively volitions and perceptions. 
 
 That perception was only logically discriminated from its 
 object on the doctrine of Descartes, will be manifest from 
 what follows: — 
 
 " I observe (he says) that whatever is done, or recently hap- 
 pens, is generally called by the philosophers passion, in re- 
 spect of the subject to which it happens, and action in respect of 
 that which causes it to take place, so that, although agent and 
 patient are often very diverse, action and passion nevertheless 
 remain one and the same thing, having these two names by 
 
NOTES. 227 
 
 reason of the two different subjects to which it can be re- 
 ferred."— De Pass. P. I. Art. 1. 
 
 '" Our perceptions are of two species : some have the mind 
 for their cause, and others the body. Those that have the 
 mind for their cause are the perceptions of our volitions, and 
 of all our imaginations that depend on it ; for it is certain that 
 we cannot will anything without perceiving by the same means 
 that we zvill it; and, although in respect of our mind it may 
 be an action to will a thing, we may say that it is also in it 
 a passion to perceive that it wills; nevertheless, because this 
 perception and volition are only in reality the same thing, the 
 denomination is always made from the more noble, and thus 
 we are not accustomed to call it a passion, but simply an 
 action." — Ibid. Art. 19. Con. on the Note in general. Art. 
 17. Prin. of Phil., P. I., § 32. Med. III., page 45. Ep., 
 P. IL, CXV., quoted below. Hamilton's Reid. Note D, pp. 
 876, 877. Compare note II, Idea. 
 
 Under the head of perception it may be necessary to remark 
 farther that the term perception (perceptio) is not used in 
 reference to sense without the adjunct sensus or sensuum — the 
 terms in this relation being sensus, sensatio, idea, and the verb 
 sentire not percipere. 
 
 11. idea — p. 10. 
 
 The meaning attached to the term idea in the writings of 
 Descartes is by no means uniform or constant. The first 
 grand distinction in the signification of the word arises from 
 its application by Descartes to denote indifferently a material 
 ■or a mental modification ; and this in relation to sense and 
 imagination. Considered with respect to these faculties, idea 
 is sometimes applied to designate the impression on the brain 
 or material organism generally, to which the idea proper or 
 mental modification is attached, and at other times to mark 
 the mental modification itself, regarded as the object of the 
 faculty. As instances of the former application of the word, 
 we may adduce the following passages : — "Ideam quam formant 
 hi spiritus." — Tract, de Homine, § 84. "Glandula ideas ob- 
 jectorum, quae in aliorum sensuum organa agunt, aeque facile 
 recipere possit." — Ibid, § 85. "Ideas quas sensus externi in 
 phantasiam mittunt." — Diopt. cap. iv. § 6. To obviate the am- 
 
228 NOTES. 
 
 biguity incidental to this twofold and quite opposite use of 
 the term, De la Forge, an eminent Cartesian, denominated the 
 movement in the organism species, or corporeal species, re- 
 serving idea for the modification of the mind alone. — Traité 
 de l'Esprit de l'Homme, chap. x. p. 99. Hamilton's Reid, p. 
 834. 
 
 Descartes himself, indeed, in the course of the controver- 
 sies to which his speculations gave rise, became aware of the 
 necessity of distinguishing in expression the material from 
 the mental idea; and in order to this he seems occasionally 
 disposed to refuse the appellation idea to the material modi- 
 fication, while he more frequently uses the term image 
 (imago), than idea in this relation. One of these passages 
 I shall quote, not only in proof of this, but also as establishing 
 the fact of the reality and distinctness of the material and 
 mental modifications. "I do not simply (he says) call by 
 the name idea the images that are depicted in the phantasy; 
 on the contrary, I do not call them by this name in so far as 
 they are in the corporeal phantasy; but I designate generally 
 by the term idea all that is in our mind when we conceive a 
 thing in whatever manner we may conceive it." — Lett, lxxv., 
 Gamier, torn. iv. p. 319. 
 
 It should be observed, however, that by idea in the sense 
 of corporeal species, Descartes did not mean a picture, like- 
 ness, or image of the object existing in the brain, but simply 
 a certain organic movement, or agitation of the nerves, de- 
 termined by the object and communicated to the brain, the 
 seat of the sensus communis. This purely material modifica- 
 tion had, on the one hand, not necessarily any resemblance 
 to the object which was the cause of it, and therefore was not 
 representative of it ; nor, on the other, should it be supposed 
 that it in any way resembled, far less was identical with, the 
 (mental) idea connected with it, since notwithstanding cer- 
 tain loose statements, there is sufficient ground to hold that, 
 on the doctrine of Descartes, the corporeal impression was 
 no object of perception or consciousness at all. As these are 
 points of essential importance towards a right comprehension 
 of the philosophy of Descartes, I may be allowed to enter 
 somewhat into detail ; and first of all, I shall refer to the pas- 
 
NOTES. 229 
 
 sages in which he has distinctly laid down the doctrines here 
 attributed to him. 
 
 " That the ideas which the external senses send into the 
 phantasy, are not images of the objects; or at least that there 
 is no need of their being like them. 
 
 " It must be observed, besides, that the mind does not stand 
 in need of images sent from objects to the brain in order to 
 perceive (as is the generally received opinion of the philoso- 
 phers) ; or at least that the nature of these images is to be 
 conceived far otherwise than is commonly done. For, as 
 philosophers consider in them nothing beyond their resem- 
 blance to the objects they represent, they are unable to show 
 how these images can be formed by the objects, and received 
 into the organs of the external senses, and finally transmitted 
 by the nerves to the brain. And they had no ground to sup- 
 pose there were such images, beyond observing that our 
 thought can be efficaciously excited by a picture to conceive 
 the object pictured; from which it appeared to them that the 
 mind must be, in the same way, excited to apprehend the ob- 
 jects which affect the senses, by means of certain small images 
 delineated in our head. Whereas we ought to consider that 
 there are many things besides images that can excite our 
 thoughts; as, for example, words and signs which in no way 
 resemble the things they signify. And if, that we may depart 
 as little as possible from the commonly received opinions, we 
 may be allowed to concede that the objects we perceive are 
 really depicted in the brain, we must at least remark that no 
 image is ever absolutely like to the object it represents; for 
 in that case there would be no distinction between the object 
 and its image; but that a partial likeness (rudem similitudi- 
 nem) is sufficient, and that frequently even the perfection of 
 images consists in their not resembling the objects as far as 
 they might. Thus, we see that engravings formed merely by 
 the placing of ink here and there on paper, represent to us 
 forests, cities, men, and even battles and tempests ; and yet of 
 the innumerable qualities of these objects which they exhibit 
 to our thought, there is none except the figure of which they 
 really bear the likeness. And it is to be remarked that even 
 this likeness is very imperfect, since on a plane surface they 
 
230 NOTES. 
 
 represent to us bodies variously rising and sinking; and even 
 that according to the rules of perspective, they frequently rep- 
 resent circles better by ovals than by other circles, and squares 
 by rhombi than by other squares, and so on in other instances ; 
 so that in order to the absolute perfection of the image, and 
 the accurate delineation of the object, the former more fre- 
 quently requires to be unlike the latter." — Diopt. cap. iv. § 6 C. 
 § 7. Prin. of Phil., p. iv. §§ 197, 198. 
 
 " Whoever has well comprised (says Descartes in contra- 
 vention of the doctrine of Regius, that all our common no- 
 tions owe their origin to observation and tradition), the ex- 
 tent and limits of our senses, and what precisely by their 
 means can reach our faculty of thinking, must admit that no 
 idea or objects are represented to us by them such as we 
 form them by thought; so that there is nothing in our ideas 
 that is not natural to the mind or to the faculty of thinking 
 which it possesses, if we but except certain circumstances that 
 pertain only to experience ; for example, it is experience alone 
 that leads us to judge that such and such ideas, which are 
 now present to the mind, are related to certain objects that 
 are out of us ; not in truth that those things transmitted them 
 into our mind by the organs of the senses such as we perceive 
 them; but because they transmitted something which gave oc- 
 casion to our mind, by the natural faculty it possesses, to form 
 them at that time rather than at another. For, as our author 
 himself avers in article 19, in accordance with the doctrine 
 of my Principles, nothing can come from external objects to 
 our mind by the medium of the senses, except certain cor- 
 poreal movements ; but neither these movements themselves 
 nor the figures arising from them, are conceived by us such 
 as they are in the organs of sense, as I have amply explained 
 in the Dioptrics : whence it follows that even the ideas of 
 motion and figures are naturally in us. And much more the 
 ideas of pain, colours, sounds, and of other similar things, 
 must be natural to us, to the end that our mind, on occasion 
 of certain corporeal movements, with which they have no re- 
 semblance, may be able to represent them to itself." — Remarks 
 on the Programme of Regius, Ep. P. i. xcix, (Ed. 1668), or 
 torn. iv. Lett, xxxviii. of Garnier's Ed. 
 
NOTES. 231 
 
 "Finally, I hold that all those (ideas) which involve no 
 negation or affirmation, are innate in us, for the organs of the 
 senses convey nothing to us of the same character as the idea 
 which is formed on occasion of them, and thus the idea must 
 have been previously in us." — Ep. P. ii. lv., or Garnier's Ed. 
 torn. iv. Lett. lxix. 
 
 " Whence do we know that the sky exists? Is it because we 
 see it? But this vision does not affect the mind unless in so 
 far as it is an idea, and an idea inhering in the mind itself, 
 and not an image depicted on the phantasy." — App. Ax. 5. p. 
 219. 
 
 " / hold that there is no other difference between the mind 
 and its ideas than between a piece of wax and the diverse 
 figures of which it is capable. And since the receiving diverse 
 figures is not properly an action in the wax, but a passion; so 
 it seems to me to be also a passion in the mind that it receives 
 this or that idea; and I consider that except its voli- 
 tions it has no actions, but that its ideas are induced upon 
 it, partly by objects affecting the senses, partly by the impres- 
 sions that are in the brain, and partly also by the dispositions 
 which have gone before in the mind itself, and by the move- 
 ments of its will." — Ep. P. i. cxv. 
 
 " The mind always receives these (its perceptions) from the 
 things represented by them." — De Pass. Part i. Art. 17. 
 
 Among Cartesians, compare De la Forge, De l'Esprit de 
 l'Homme, cap. x. Geulinx, Dictata in Prin. Phil. P. iv. § 189. 
 Malebranche, Recherche de la Vérité, Liv. ii. ; De l'Imagina- 
 tion, chap. v. § 1 ; also Liv. i. Des Sens, chap. x. § 5. 
 
 I am aware that some maintain that Descartes held the 
 material impression to be an object of consciousness, an opin- 
 ion to which both Reid and Stewart incline (see Reid's Essays 
 on the Intellectual Powers ; Essay ii., chap. viii. ; Stewart's 
 Dissertation, note N. p. 245; Elements, Part i. chap, i., note, 
 p. 45, ed. 1850.) That such is not the doctrine of Descartes, is 
 manifest from the passages already cited. It may be necessary, 
 however, in order to a fuller consideration of the question, to 
 refer to those doubtful statements which at first sight appear 
 to give some countenance to the supposition. 
 
 I shall, first of all, quote and give references to what seem 
 the strongest of the ambiguous passages. "I easily under- 
 
232 NOTES. 
 
 stand," he says, "that if some body exists with which my mind 
 is so united as to be able, as it were, to consider it when it 
 chooses, it may thus imagine corporeal objects, so that this 
 mode of thinking differs from pure intellection only in this 
 respect, that the mind in conceiving, turns in some way upon 
 itself, and considers some one of the ideas it possesses within 
 itself; but, in imagining, it turns toward the body, and con- 
 templates in it some object conformed to the idea which it 
 either conceived of itself or apprehended by sense." — Med. 
 vi., page 86. 
 
 " The former, or corporeal species which must be in the 
 brain in order to imagination, are not thoughts; but the op- 
 eration of the mind imagining or turning towards these species, 
 is a thought." — Ep. p. ii. liv. (De Pass. p. i., art. 35. Ap- 
 pendix, Def. ii., p. 215). 
 
 These and similar passages might seem, at first sight, to 
 countenance the supposition, that Descartes admitted a knowl- 
 edge of the corporeal species or organic impression. Such an 
 interpretation is, however, rash and untenable, were there no 
 other ground for rejecting it, save the various contradictions 
 of the principles of the philosophy of which it is supposed to 
 form a part, for these are so many and so manifest, that we 
 could hardly suppose such a thinker as Descartes to have al- 
 lowed them to escape his notice. Before showing that the 
 passages in themselves do not really warrant the interpretation 
 here referred to, I shall point out its general inconsistency, 
 not only with the main principle, but with certain particular 
 doctrines of Cartesianism, and these the most important and 
 distinctive. 
 
 In the first place, then, had Descartes admitted a knowledge 
 of the material impression, either in sense or imagination, and, 
 be it observed, an immediate knowledge is the only supposable, 
 he must have allowed an immediate consciousness of matter, 
 for the corporeal species is a material object. But this would 
 have been to contradict the fundamental principle of his philos- 
 ophy, according to which, mind, on account of its absolute 
 diversity from body, is supposed to be able to hold no im- 
 mediate converse with matter, but only to be cognisant of it 
 by means of its own modifications, determined hyperphysically 
 on occasion of certain affections of the body with which it is 
 
NOTES. 233 
 
 conjoined. And thus, if the mind be immediately cognisant of 
 the corporeal species, what occupies the prominent and distinc- 
 tive place in Cartesianism, — viz., the host of mental ideas rep- 
 resentative of the outward object, becomes forthwith the 
 superfluity and excrescence of the system ; for if the mind can 
 take immediate cognisance of the corporeal species, i. e. of 
 matter, why postulate a mental representation in order to the 
 perception of the outward object? 
 
 But in the second place, whether the material impression be 
 an object of consciousness or not, Descartes must still be held 
 to allow the existence of a mental modification or idea. The 
 species, therefore, on the hypothesis that it is an object of 
 consciousness, is either really identical with the mental idea, 
 or it is different from it. To take the former supposition, or 
 that of the identity of the material and mental modifications, 
 it will follow that mind and matter are no longer distinguish- 
 able, are no longer diverse substances, seeing their modifica- 
 tions coincide — a tenet no less at variance with the entire 
 course of the speculations of Descartes, than is the doctrine 
 from which it flows with the numerous explicit statements, in 
 which he declares the total diversity of the material and men- 
 tal ideas, as modifications of substances in themselves distinct. 
 But the organic impression, if not identical with, must be di- 
 verse from, the mental idea. Now as, on the hypothesis in 
 question, the material idea is perceived, and as the mental is 
 likewise an object of perception, there must be in each of the 
 faculties of sense and imagination a two- fold object. For such 
 a doctrine, there is not the shadow of a ground in all the writ- 
 ings of Descartes. 
 
 But, in the third place, let it be supposed that Descartes did 
 not allow the existence of mental ideas at all, and therefore 
 only a single object in perception, and that the organic impres- 
 sion, even with this gratuitous allowance a palpable contra- 
 diction in the doctrine of the philosopher would arise. The 
 organic impression, in order to constitute the representative 
 idea of the object, must represent the object, not suggest it 
 or represent it materially (materialiter), as a natural sign, for 
 the object could not be simply suggested to the mind or thus 
 represented, without appearing in a mental modification or 
 idea, which is contrary to the hypothesis. But an object that 
 
234 NOTES. 
 
 is material, and at the same time representative, must, if it 
 represent by itself, represent intentionally (intentionaliter) ; 
 in other words, it must resemble the object it represents, or 
 be the image or likeness of it. It is the property of mind 
 alone to be capable of representing something different from 
 itself, or even quite opposed, in a modification not at all re- 
 sembling the thing represented; as, for example, an extended 
 object in an unextended modification. But the resemblance 
 of the material idea to the outward object, is a doctrine ex- 
 plicitly denied by Descartes. — (Vide Remarks on Programme 
 of Regius, quoted above, Prin. of Phil., p. iv., §§ 197, 198.) 
 
 But finally, the whole hypothesis makes Descartes contradict 
 not only his own doctrine of representation, but destroy the 
 general conditions of any representative doctrine whatever; 
 for, as the only ground on which a doctrine of representation 
 can be supposed necessary, is that the mind is not immediately 
 percipient of the outward object, if Descartes at the same time 
 holds that the representation, itself material and an object ex- 
 ternal to the mind, because existing in the brain, is perceived, 
 he must allow to the mind, at first hand, that power on the 
 denial of the existence of which the assertion of the need 
 of a representative object is founded. 
 
 These considerations are, I think, sufficient to show, that it 
 is at least highly improbable, that Descartes meant in the pas- 
 sages quoted to allow to the mind a consciousness of the or- 
 ganic impression in sense and imagination. To have done so, 
 would have been to fill his philosophy with anomalies and 
 contradictions of the most palpable kind. 
 
 But let us attend shortly to the passages themselves, to dis- 
 cover whether they render such an interpretation of them im- 
 perative. In the passages quoted, the mind is said to turn it- 
 self towards the species, and these again are said to inform 
 (informare) the mind. 
 
 With regard to the first phrase, conversion towards the 
 species, it will be found, by a reference to the passages in 
 which it occurs, that it is always used as descriptive of the 
 acts of sense and imagination, when these are spoken of in 
 contrast to the act of the pure intellect, or that faculty whose 
 exercise is independent of all organic impression ; and then 
 the contrast indicated is in the origin or source of the ideas, 
 
NOTES. 235 
 
 or objects of these faculties, those of sense and imagination 
 having their (remote) source in body, — those of intellect, their 
 (immediate) origin in the mind itself. In this way, all that 
 conversion towards the species indicates, is merely that the 
 mind does not receive certain ideas directly from itself but is 
 in some way dependent for at least their actual presence on 
 certain . conditions of the bodily organism. And this, it is 
 manifest, does not necessarily imply the consciousness by the 
 mind of the organic impression. 
 
 Again, the corporeal species may in its turn be said to 
 inform the mind (informare mentem), inasmuch as it is to 
 it the mental modification or idea, viewed apart from its hy- 
 perphysical origin, is immediately attached, and on occasion of 
 which it is revealed to consciousness; and this on the law of 
 the union of mind and body, as parts of the same whole. In 
 the same sense, Deity is said to inform the mind, in so con- 
 stituting it as that in the course of the development of its 
 powers, the knowledge of himself should naturally arise. 
 
 But, in the second place, the species may, in a literal sense, 
 be said to inform the mind, for the word, in its strict accep- 
 tation, merely denotes the giving a particular form or shape 
 to a thing; and in the Cartesian phraseology, the spiritual no- 
 tions or mental ideas' were but the different forms of the mind 
 in which its acts were clothed, limited, and determined. — Vide 
 Appendix, Def. ii. p. 215. De la Forge, De l'Esprit, chap, x., 
 p. 131 and passim. Claub. Op. p. ii., p. 606. 
 
 The doctrine of Descartes on this point seems to be well 
 put by Chauvin, when, after noticing the doctrines of certain 
 of the Peripatetics regarding species, he says: — "There are, 
 however, among more recent philosophers, not a few who re- 
 tain the nomenclature of species impressa and expressa. But 
 with them the species impressa is nothing more than a certain 
 motion impressed either mediately or immediately, by exter- 
 nal objects, on -the parts of the body, and thence by the nerves 
 transmitted to the brain, or a certain commotion of the fibres 
 of the brain, proceeding from the agitation of the animal spirits 
 flowing in the brain; which, as they have no resemblance to 
 the objects of nature, are esteemed representamens of these 
 things, on no other account than because the mind on occasion 
 of them [i. e., the motions], makes the things present to itself, 
 
236 NOTES. 
 
 and contemplates the same in its own ideas therefrom arising. 
 * * * * But the species expressa is nothing more than that 
 notion of the mind which is expressed on the presence of 
 the species impressa, and by attention to and inspection (intui- 
 iione) of which the thing itself is known." — Lexicon Rationale, 
 Species, (1692). Con. Prin. of Phil., part iv. §§ 189, 197, 198. 
 
 But lastly, the whole ambiguity is probably due to the ex- 
 treme timidity of the philosopher, and his anxious solicitude 
 to bring the results of his own independent reflection into an 
 apparent harmony with the opinions generally received in his 
 time; which led him frequently to clothe his really new doc- 
 trines in the current forms of expression. 
 
 There is thus, not even on the special ground of the am- 
 biguous passages themselves, any reason to suppose that Des- 
 cartes ever departed from a doctrine essential to the con- 
 sistency of his philosophy, viz., the non-consciousness of the 
 organic impression. So much for idea as a material or organic 
 modification. 
 
 We must now, however, consider idea in reference to mind, 
 ». e., as an object of consciousness. In this relation the funda- 
 mental notion to be attached to the term, as used by Descartes 
 and the Cartesians, is that of a representative thought, or an 
 object of consciousness, in and by the knowledge of which we 
 become aware of something distinct from this object itself. 
 Idea, Descartes says, is to be taken "pro omni re cogitatâ 
 quatenus habet tantum esse objectivum in intellectu." — Diss, de 
 Meth P. iv. note. "Idea est ipsa res cogitatio quatenus est ob- 
 jective in intellectu." Again, idea is "cogitato tanquam rei 
 imago." — Con. Med. iii. 45, and Works passim. De La Forge, 
 De l'Esprit, chap. x. pp. 128, 131. 
 
 It is necessary, however, with a view to an adequate under- 
 standing of the Cartesian philosophy, to distinguish the two 
 aspects under which the same idea was viewed by Descartes 
 and his followers. The mental idea, while really one and indi- 
 visible, was considered in two logically distinct relations, viz., 
 both as an object and as a medium of knowledge, that is, in 
 reference to the mind knowing and the object known. This 
 distinction is made by Descartes in several passages of the 
 Meditations. Thus, "If ideas are taken in so far only as they 
 are certain modes of consciousness, I do not remark any dif- 
 
NOTES. 237 
 
 ference or inequality among them, and all seem in the same 
 manner to proceed from myself; but considering them as im- 
 ages, of which one represents one thing and another a differ- 
 ent, it is evident that a great diversity obtains among them." — 
 Med. iii. p. 48. Preface of Med. p. 10. 
 
 This distinction of idea as act and as representative ob- 
 ject, pervades the whole body of Cartesian literature. Thus, 
 to take an example, "Every concept or idea," says Clauberg, 
 "has a twofold dependence ; the one from the conceiving and 
 thinking intellect, in as far as it is an act; the other from the 
 thing conceived or like, of which, to wit, it is the representa- 
 tion or image, or whence it is struck out by imitation." — Op. 
 P. ii. p. 607 (Ed. 1691). Con. De la Forge, De l'Esprit, chap. 
 x. pp. 128, 131. Flenderus, Logica Contracta Claubergiana 
 (4th ed.) § 5, P- 12. 
 
 Idea has thus with the Cartesians a twofold relation or de- 
 pendence (realitas, perfectio, esse, dependentia). In so far as 
 it is an act or mode of the mind (operatio mentis, intellectus) , 
 idea possesses a formal and proper being {esse formate sen 
 proprium) ; in so far as it is the representation of the object 
 thought (imago rei cogitatae), or in the place of that object 
 (in vice illius), it has an objective or vicarious being (esse 
 objectivum sive vicarium). Again, idea, as standing in this 
 double relation or dependence, is said to have a twofold cause, 
 viz., an efficient and an exemplary. In so far as a mode of 
 consciousness, the idea has its efficient cause in intellect or in 
 the mind itself (uti operans suae operationis causa) ; in so far 
 as representative, the object is the exemplary cause, standing 
 in relation to the idea as the archetype to the ectype, the prin- 
 cipal to the vicarious. 
 
 It is the discrimination of idea as a mental operation or 
 representative object, which affords the logical distinction of 
 perception and idea, to be met with on all hands in Cartesian 
 literature. "By the term idea," says Descartes himself, "I un- 
 derstand that form of any thought by the immediate perception 
 of which I am conscious of that same thought." — Appendix, 
 Def. ii. p. 215. 
 
 " I have said," says Arnauld, "that I take perception and 
 idea for the same thing. It should be observed, however, that 
 this thing, although one, has two relations ; the one to the mind 
 
238 NOTES. 
 
 which it modifies, the other to the thing perceived, in so far 
 as it is objectively in the mind, and that the word perception 
 more distinctly marks the former relation, and idea the latter. 
 Thus, the perception of a square marks more directly my mind 
 as perceiving a square; and the idea of a square marks more 
 directly the square in so far as it is objectively in my mind." — 
 Des Vraies et des Fausses Idées, chap. v. Def. 6. Con. De la 
 Forge, De l'Esprit, chap. x. pp. 128, 140. 
 
 It should be observed, however, with regard to this distinc- 
 tion of idea and perception, that with Descartes perception is 
 sometimes used where, in accordance with the propriety of 
 language, we should have expected idea. Thus he says, "The 
 mind always receives these (its perceptions) from the things 
 represented by them." (De Pass., P. i. Art. 17.) On the 
 other hand, we find idea where, in accordance with his gen- 
 eral nomenclature, we should have looked for perception. 
 "When I will and fear, because at the same time I perceive 
 that I will and fear, the volition itself and fear are reckoned 
 by me among ideas." — Ob. et Resp. Tertiae, Ob. v. p. 98 (Ed. 
 1670). 
 
 Looking to ideas as the immediate objects of knowledge or 
 perception, and considering them in relation to the faculties 
 of which they are the objects, they may be classed as ideas 
 of sense, of imagination, and of the pure intellect, in the ex- 
 ercise of each of which powers we are said to be apprehensive 
 or percipient of ideas. But, as the objects of these powers, 
 ideas differ both in their origin, and according to the character 
 of the objects they represent. In the first relation, ideas arise 
 either simply from the mind, as those of the pure intellect, or 
 from the mind on occasion of body, modified by the corporeal 
 species, as those of sense and imagination. Considered as to 
 their origin, the ideas of sense and imagination thus stand in 
 contrast to those of the pure intellect, for in sense and imagin- 
 ation there is always a physical impression or corporeal species 
 as the cause or occasion of the mental idea; whereas the in- 
 tellect, as deriving its ideas from the mind itself, has no need 
 of a material organ or of corporeal species. The ideas of 
 sense and imagination, while they agree in being the result, 
 though hyperphysically determined, of a physical antecedent 
 in the form of the corporeal species, and thus in both depend- 
 
NOTES. 239 
 
 ing on the bodily organism, nevertheless differ in this, that 
 the species to which the idea is attached is in the case of sense 
 immediately dependent on the presence and action of external 
 objects; while in imagination it depends only remotely on ex- 
 ternal objects, and proximately on the will, the memory, and 
 the action of the animal spirits. 
 
 But the chief contrast of ideas arises from the character of 
 the objects they represent. In this relation, on the Cartesian 
 doctrine, ideas fall into two great classes. The first compre- 
 hends all ideas of the individual and picturable, in other words, 
 all the objects of sense and imagination; the second contains 
 all our notions of the general, relative, or unpicturable — in 
 other words, the ideas of the pure intellect. (Con. Med. vi. 
 pp. 84-89; Prin. of Phil. P. i. §73. Lett, lxxv., vol. iv. p. 
 318 of Garnier's éd., or vol. vi., L. lxii. duod. éd. De la 
 Forge, De l'Esprit, chap, xviii. pp. 298-302.) — Under sense it 
 should be observed that idea, in the writings of Descartes as 
 well as of others in the Cartesian school, denotes indifferently 
 the apprehension of the primary and the sensations of the sec- 
 ondary qualities of matter. Thus, Descartes speaks of the sen- 
 sation or idea (sensus vel idea) of colour and heat. Male- 
 branche limited idea (idée) to the apprehension of the pri- 
 mary, reserving sentiment to designate the sensations of the 
 secondary qualities. — As the secondary qualities on their sub- 
 jective side were held by the Cartesians to be merely modifi- 
 cations of the percipient subject, and not to exist in nature as 
 in consciousness, idea as applied to them (which was not gen- 
 erally the case out of the writings of Descartes), was not rep- 
 resentative. Vide Prin. of Phil. P. i. §§ 69, 70, 71. 
 
 in. objective reality — (reaiitas objectiva) — p. 18. 
 After what has been already said of the twofold relation of 
 idea in the philosophy of Descartes, it is unnecessary to add 
 much by way of explanation of the term objective reality. 
 This, as we have said, denotes that aspect of a representative 
 thought in which it is considered in relation to the object rep- 
 resented; hence the object is said to possess objective reality 
 in so far as it exists by representation in thought (quatenus ob- 
 jicitur intellectui) . This use of the term objective, it will be 
 remarked, is precisely opposed to the more modern (Kantian) 
 acceptation of the same word, and corresponds, to a certain 
 
240 NOTES. 
 
 extent, with the counter-term subjective; for objective reality 
 (i. e., the reality of representation) is in truth a subjective 
 reality. 
 
 It may be of importance to note the two relations from 
 which the representative reality of an idea is distinguished in 
 Cartesian literature, with their appropriate designations. In 
 the first place, the representative perfection (being) of an 
 idea, was distinguished from the object of the idea in so far 
 as it possessed an absolute existence, or existence independent 
 of thought. In this relation the object was said to possess 
 realitas actualis, formalis, as opposed to realitas objectiva. 
 {Con. Med. iii. pp. 49; Med. vi. p. 92.) The object as 
 it exists in nature was by other philosophers, and among these 
 by some of the Cartesians, called ens principale, reale, funda- 
 mentale (quasi fundamentum ideae). 
 
 In the second place, the representative being of an idea was 
 distinguished from its relation to the mind of which it is the 
 act, and in this aspect idea, so far as act, was said to possess 
 esse reale, materiale, formale (q. forma quaedam mentis, and 
 this in contrast with objectivum) , proprium; in relation to the 
 object represented, it was said to possess esse intentionale, 
 formale (and this in contrast with materiale), objectivum, 
 vicarium; these are the strictly contrasted appellations. The 
 esse objectivum was also called representativum, cognitum, in 
 mente, tanquam in imagine, per imitationem. Con. Claub. Op. 
 P. ii. pp. 607-617. Hamilton's Reid, pp. 806, 807. 
 iv. from or through the senses — (vel a sensibus vel per sen- 
 sus) — p. 22. 
 
 "From the senses, that is, from sight, by which I first per- 
 ceived light, and then by its aid colours, figures, magnitudes, 
 and all similar things ; through the senses, that is, through 
 hearing, in apprehending the words of men." — Claubergius, in 
 h. loc. Op. P. ii. p. 1 182. 
 
 v. thought — (cogitatio, pensée; cogitare, penser) — p. 25. 
 
 Thought, (cogitatio, pensée), is, in the Cartesian phrase- 
 ology, applied to designate all that takes place within us, of 
 which we are immediately conscious, i. e., all the modifications 
 of the mind or thinking principle. Thought is thus but another 
 term for consciousness, and embraces all the acts of the will, 
 
NOTES. 241 
 
 the intellect, the imagination, and senses. — Med. iii. p. 45; 
 Prin. of Phil. P. i. § 9; Resp. ad. Sec. Object. Def. i. (Ap- 
 pendix p. 215.) 
 
 " Thought," says De la Forge, "I take for that perception, 
 consciousness, or internal knowledge which each of us feels 
 immediately by himself when he perceives what he does or 
 what passes in him." — De l'Esprit, chap. iii. p. 14, chap. vi. 
 p. 54. Arnauld, Des Vraies et des Fausses Idées, chap. v. 
 def. i. 
 
 " Mens," says Claubergius, "si vult cogitât, si non vult cog- 
 itât, si amat cogitât, si odit cogitât, si affirmât cogitât, si negat 
 cogitât, si dubitat cogitât, si demonstrat cogitât, somniando 
 cogitât, vigilando cogitât, sentiendo cogitât, imaginando cogi- 
 tât, &c, atque ita in qualibet ejus functione cogitatio involvi- 
 tur."— Op. P. ii. p. 600 ; P. i. p. 188 ; Log. P. i. § 102. 
 
 Consciousness is thus, in the doctrine of the Cartesians, the 
 general condition of our mental modifications, and in no way 
 really distinct from the activities and passivities of which it 
 is the condition. Though, in a sense already explained (as 
 opposed to volition), perception is said to be contained under 
 consciousness as its genus, they are yet nearly convertible 
 terms. The difference between the two forms of expression 
 seems to be, that thought, while embracing all the modifica- 
 tions of mind, whether volitions or perceptions, is not dis- 
 tinguished from the former as a passivity, while perception is. 
 Thought, as thus denoting a mental modification both in its 
 active and passive relation, marks the opposition and contrast 
 of the modification to its negative, the extended, i. e., matter, 
 while viewed as a perception the phenomenon is regarded 
 mainly in reference to its simple existence in consciousness, 
 or as an apprehended property of mind. It seems to be in ac- 
 cordance with this view that the mind is uniformly spoken of 
 as res cogitans (not percipiens) when opposed to its negative, 
 the unthinking and extended. 
 
 vi. innate ideas — (ideae innatae) — p. 46. 
 
 By innate idea, Descartes meant merely a mental modifica- 
 tion which, existing in the mind antecedently to all experience, 
 possesses, however, only a potential existence, until, on oc- 
 
242 NOTES. 
 
 casion of experience, it is called forth into actual conscious- 
 ness. 
 
 It is worthy of remark, in connection with the question of 
 innate ideas, that the chief ground on which Descartes holds 
 that certain of our judgments are prior to experience and na- 
 tive to the mind, is the impossibility of deriving them as uni- 
 versal from individual corporeal movements, which, if efficient, 
 could give rise to modifications merely individual. 
 
 It will be seen, however, from the passages quoted below, and 
 from a comparison of them with the passage quoted at pp. 229- 
 231, of these notes, that Descartes held a much wider doctrine 
 of innate ideas than the modern, and one the principle of which 
 could not fail sooner or later to result in the doctrine of Oc- 
 casional Causes, to explain the connection between the cor- 
 poreal antecedent, which had no causal power, and the rise of 
 the mental modification into actual consciousness. 
 
 The following is the article (xii.) in the Programme of 
 Regius which gave occasion to Descartes to make an explicit 
 statement of his doctrine of innate ideas. 
 
 " Mens," says Regius, " non indiget ideis, vel notionibus, vel 
 axiomatibus innatis : sed sola ejus facultas cogitandi, ipsi, ad 
 actiones suas peragendas, sufficit." On this Descartes remarks: 
 "In this article he (Regius) appears to differ from me merely 
 in words ; for when he says that the mind has no need of ideas, 
 or notions, or axioms that are innate [or naturally impressed 
 upon it], and meanwhile concedes to it a faculty of thinking 
 (that is, a faculty natural to it or innate), he affirms my doc- 
 trine in effect, though denying it in word. For I have never 
 either said or thought that the mind has need of innate (nat- 
 ural) ideas, which are anything different from its faculty of 
 thinking; but when I remarked that there were in me certain 
 thoughts which did not proceed from external objects, nor 
 from the determination of my will, but from the faculty of 
 thinking alone which is in me, that I might distinguish the 
 notions or ideas, which are the forms of these thoughts, from 
 others adventitious or factitious, I called them innate in the 
 same sense in which we say that generosity is innate in certain 
 families, in others certain diseases, as gout or gravel, not that, 
 therefore, the infants of those families labour under those 
 
NOTES. 243 
 
 diseases in the womb of the mother, but because they are born 
 with a certain disposition or faculty of contracting them." 
 
 Again, on Art. xiii., he says — "What supposition is more 
 absurd than that all the common notions which are in the mind 
 arise from these corporeal motions, and cannot exist without 
 them? I should wish our author to show me what that cor- 
 poreal movement is which can form any common notion in our 
 mind ; for example, — that the things which are the same with a 
 third are the same with each other, or the like. For all those 
 motions are particular; but these notions are universal, and 
 possess no affinity with motions, nor any relation to them." 
 
 " He (Regius) proceeds, in Article xiv., to affirm that the 
 very idea of God which is in us arises not from our faculty 
 of thinking, in which it is innate, but from divine revelation, 
 or tradition, or the observation of things. We shall easily 
 discover the error of this assertion, if we consider that a thing 
 can be said to be from another, either because that other is its 
 proximate and primary cause, or because it is simply the re- 
 mote and accidental, which, in truth, gives occasion to the 
 primary to produce its own effect at one time rather than 
 at another. Thus, all workmen are the primary and prox- 
 imate causes of their own works ; but they who commission 
 them, or offer payment for the execution of the works, 
 are the accidental and remote causes, because the works 
 would not perhaps have been done without the order. It 
 cannot be doubted but that tradition or the observation of 
 things is the remote cause, inviting us to attend to the idea 
 of God which we possess, and to exhibit it in presence to 
 our thought. But that it is the proximate cause (effectrix) 
 of that idea can be alleged only by one who holds that we 
 can know nothing of God beyond the word God, or the 
 corporeal figure exhibited to us by painters in their rep- 
 resentations of God. Inasmuch as observation, if it be of 
 sight, presents nothing of its own proper power to the mind 
 except pictures, and pictures whose whole variety is de- 
 termined solely by that of certain corporeal movements, as 
 our author himself teaches; if it be of hearing, observation 
 presents nothing but words and sounds; if of the other 
 senses, it presents nothing that can be related to God. And, 
 
244 NOTES. 
 
 indeed, it is manifest to every one that sight properly and by 
 itself presents nothing except pictures, and hearing nothing 
 but words or sounds; so that all which we think beyond 
 these words or pictures, as the signifkates of them, are 
 represented to us by ideas coming from no other source than 
 our faculty of thinking, and therefore natural to it; that is 
 always existing in us in power. For to be in any faculty is 
 not to be in act but in power only, because the very word 
 faculty designates nothing but power." — Lett, xxxviii. Gar- 
 nier's Ed. Tom. iv. Not. in Prog. Latin (1670), p. 175. 
 
 On the celebrated question (says De la Forge) as to 
 whether the ideas of the mind are born with it, or acquired, 
 I reply that they are both one and other. They are born 
 with it, not only because it has never received them from 
 the senses, but also because it is created with the faculty of 
 thinking and forming them, which is the proximate and prin- 
 cipal cause of them; in the same way that we say gout or 
 gravel is natural to certain families, when the members of 
 them bring with them proximate dispositions to those mala- 
 dies. But those ideas are acquired, and not natural, if by 
 natural we understand that they are in the substance of the 
 soul as in a conservatory, in the manner in which pictures are 
 disposed in a gallery, that we may consider them as we please ; 
 for there is none of them in particular that needs to be ac- 
 tually present to our mind, which, being a thinking substance, 
 can have nothing actually present to it of which it has no 
 knowledge. It is for this reason they are contained in the 
 mind only in power, and not in act." — De l'Esprit, chap, x., 
 pp. 143, 144. Con. Clauberg. on Med. iii. Op., P. i., 391. 
 
 vu. formally and eminently {formaliter, eminetiter) — p. 
 49- 
 Besides the application of the word formal already noticed, 
 viz. (i),Jn opposition to objective, to denote the object as 
 it exists in nature; and (2) as a synonyme for objective in 
 contrast to material, to denote the idea so far as it is a rep- 
 resentation, there is still another use of the term in the writ- 
 ings of Descartes and in the Cartesian literature. In this third 
 application, formal is opposed to eminent, and refers to the 
 relation of cause and effect. The contrast indicated by these 
 
NOTES. 245 
 
 terms in this relation is in regard to the manner in which a 
 cause is said to contain its effect. A cause, as the sum of 
 the perfection or reality of its effect, may contain this reality 
 in either of two ways, and must in one of them. On the one 
 hand, if the perfection of the effect be contained in the cause 
 in the same mode in which it exists in the effect, or, if the 
 cause be only possessed, in this respect, of equal perfection 
 with the effect, the reality of the effect is said to be in the 
 cause formally (formaliter, q. d. secundum eandem formam 
 et rationem). Thus, the print of the foot has formally the 
 quantity and figure of the foot, and is thus formally in its 
 cause. In the same way, any absolute perfection is formally 
 in God. On the other hand, if the effect be contained in the 
 cause, not as it is in itself, or according to its intrinsic form, 
 essence, or proper definition, but in a higher grade or mode 
 of perfection (gradu, modo eminentiori) , it is said to be in 
 its cause eminently. In this sense the Divine intellect con- 
 tains the human, since God knows, but without the imperfec- 
 tions incident to the exercise of our faculties of cognition. 
 A cause containing eminently thus contains all the reality of 
 the effect more perfectly than the effect itself. This distinc- 
 tion, borrowed from the schoolmen, has an important appli- 
 cation, in the philosophy of Descartes, to the question of the 
 proof of the existence of God through his idea. — Con. Med. 
 iii., p. 48, etc. Appendix, def. iv., p. 216; Ax. iv., p. 219 
 Spinoza, Prin. Phil. Cart, P. i., vol. i., p. 16. (Paulus.) 
 Clauberg. Exercit. vi., p. 613, § 5, 6. (Ed. 1691.) Flender. 
 Log., § 50. Chauvin, Lex. Rat., voc. Continere. De Vries, 
 (Anti-Cart.) Exercit. vi., § 4, pp. 55, 56. (Ed. 1695.) 
 
 vin. pure intellection (intellectio pura) — p. 147. 
 
 Intelligence, understanding (intellectus) , is the general 
 name in Cartesian literature of the powers of cognition in 
 contrast to those of will ; and in this sense the term compre- 
 hends all the acts, whether of sense, memory, imagination, or 
 of intellect proper. But intelligence has, besides its general, 
 a special and restricted signification ; and this especially when 
 the qualifying epithet pure is joined with it. Pure intellection 
 {intellectio pura) denotes not knowledge in general, but the 
 knowledge, whether individual or general, of the mental phse- 
 
2 4 6 NOTES. 
 
 nomena, and generally of all those objects we are capable of 
 thinking in the narrower sense of the word, but cannot imag- 
 ine, or hold up to our mind in an image or picture. In a 
 word, with the Cartesians the pure understanding is the fac- 
 ulty of the unpicturahle, imagination of the picturable. 
 Whatever knowledge, therefore, we may be able to reach of 
 mind or of God, — of body in its general relations, or in such 
 of its properties as are either too great or too minute for 
 apprehension by sense, — of those judgments which are native 
 to the mind — falls within the province of the pure intellect. 
 
 It should be observed that in this faculty, according to its 
 application, there is knowledge either without or with ideas 
 — in other words, either an immediate or a mediate knowl- 
 edge. It is by the pure intellect alone that we take cognisance 
 of our own mind in its phamomena, and these we can imme- 
 diately, or without idea, apprehend. But of everything dis- 
 tinct from ourselves which we know by the intellect, we can 
 have but a mediate knowledge, or a knowledge by idea. The 
 distinction of the ideas of the imagination and the intellect, 
 is nearly similar to the distinction of thoughts into those of 
 the individual and general, or of intuitions (in the older sense 
 of the term), and notions or concepts. — Con. Note ii., Idea. 
 Med. iv. p. 64. Med. vi. pp. 84-86. Prin. of Phil., § 73. 
 Lett, lxxv., Gamier, torn. iv. p. 318 (or lxii. of vol. vi. Ed. 
 i2mo.) Ep. P. i., xxx. Reg. ad Direct. Ing., R. xii. De la 
 Forge, De l'Esprit, chap, xviii, pp. 298-302. Hamilton's Reid, 
 p. 291. Note. 
 
 ix. motion — p. 191. 
 
 The following section of the Principles is added to those 
 given in the text, from its bearing logically and historically 
 on the doctrine of Occasional Causes as arising out of Car- 
 tesianism : — 
 
 " That God is the primary cause of motion ; and that he al- 
 ways preserves the same quantity of motion in the universe. 
 
 " After having thus adverted to the nature of motion, it is 
 necessary to consider its cause, and that the twofold: firstly, 
 the universal and primary, which is the general cause of all 
 the motions in the world; and secondly, the particular, by 
 which it happens that each of the parts of matter acquires 
 
NOTES. 247 
 
 the motion which it had not before. And with respect to the 
 general cause, it seems manifest to me that it is none other 
 than God himself, who, in the beginning, created matter along 
 with motion and rest, and now by his ordinary concourse 
 alone preserves in the whole the same amount of motion and 
 rest that he then placed in it. For although motion is noth- 
 ing in the matter moved but its mode, it has yet a certain and 
 determinate quantity, which we easily understand may remain 
 always the same in the whole universe, although it changes 
 in each of the parts of it. So that, in truth, we may hold, 
 when a part of matter is moved with double the quickness of 
 another, and that other is twice the size of the former, that 
 there is just precisely as much motion, but no more, in the 
 less body as in the greater; and that in proportion as the mo- 
 tion of any one part is reduced, so is that of some other and 
 equal portion accelerated. We also know that there is per- 
 fection in God, not only because he is in himself immutable, 
 but because he operates in the most constant and immutable 
 manner possible : so that with the exception of those muta- 
 tions which manifest experience, or divine revelation renders 
 certain, and which we perceive or believe are brought about 
 without any change in the Creator, we ought to suppose no 
 other in his works, lest there should thence arise ground for 
 concluding inconstancy in God himself. Whence it follows 
 as most consonant to reason, that merely because God di- 
 versely moved the parts of matter when he first created them, 
 and now preserves all that matter, manifestly in the same 
 mode and on the same principle on which he first created it, 
 he also always preserves the same quantity of motion in the 
 matter itself." — Part ii. § 36. 
 
 X. SECOND ELEMENT — p. IQÇ>. 
 
 " Thus we may reckon upon having already discovered two 
 diverse forms in matter, which may be taken for the forms 
 of the first two elements of the visible world. The first is 
 that of the scraping {raclure) which must have been separated 
 from the other parts of matter, when they were rounded, and 
 is moved with so much velocity that the force alone of its 
 agitation is sufficient to cause it, in its contact with other 
 bodies, to be broken and divided by them into an infinity 
 
24 8 NOTES. 
 
 of small particles that are of such a figure as always exactly 
 to fill all the holes and small interstices which they find 
 around these bodies. The other is, that of all the rest of the 
 matter whose particles are spherical and very small in com- 
 parison of the bodies we see on the earth, but nevertheless 
 possess some determinate quantity, so that they can be di- 
 vided into others much smaller; and we will still find in ad- 
 dition a third form in some parts of matter, to wit, in those 
 which, on account of their size and figure, cannot be so easily 
 moved as the preceding; and I will endeavour to show that 
 all the bodies of the visible world are composed of these three 
 forms, which are found in matter, as of three diverse ele- 
 ments, to wit, that the sun and the fixed stars have the form 
 of the first of these elements, the heavens that of the second, 
 and the earth with the planets and comets that of the third. 
 For since the sun and the fixed stars emit light, since the 
 heavens transmit it, and since the earth, the planets, and 
 comets reflect it, it appears to me I have ground for these 
 three differences, [luminousness, transparency, and opacity 
 or obscurity, which are the chief we can relate to the sense of 
 sight], in order to distinguish the three elements of the visible 
 world." — Prin. of Phil. Part. iii. ? § 52. Con. Chauvin, Lex. 
 Rat., Art. Elementum. 
 
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