HOME UNIVERSITY LIBRARY HOME UNIVERSITY LIBRARY OF MODERN KNOWLEDGE No. 96 Editors : HERBERT FISHER, M.A., F.B.A. PROF. GILBERT MURRAY, LlTT.D., LL.D., F.B.A. PROF. J. ARTHUR THOMSON, M.A. PROF. WILLIAM T. BREWSTER, M.A. A complete classified list of the volumes of THE HOME UNIVERSITY LIBRARY already published will be found at the back of this book. A HISTORY OF PHILOSOPHY BY CLEMENT C. J. WEBB NEW YORK HENRY HOLT AND COMPANY LONDON WILLIAMS AND NORGATE REPLACING CONTENTS CHAP. PACK I PHILOSOPHY AND ITS HISTORY . . 7 II PLATO AND HIS PREDECESSORS . 14 III ARISTOTLE AND OTHER SUCCESSORS OF PLATO ..... 47 IV PHILOSOPHY AND THE RISE OF CHRISTIANITY .... 78 V PHILOSOPHY DURING THE MINORITY OF MODERN EUROPE . . .111 VI PHILOSOPHY AT THE COMING OF AGE OF MODERN EUROPE . . . 127 VII DESCARTES AND HIS SUCCESSORS . 143 VIII LOCKE AND HIS SUCCESSORS . . 171 IX KANT AND HIS CONTEMPORARIES . 186 X THE SUCCESSORS OF KANT . . 210 BIBLIOGRAPHY s 2 ^2 INDEX 255 A HISTORY OF PHILOSOPHY CHAPTER I PHILOSOPHY AND ITS HISTORY " WISE I may not call them ; for that is a great name which belongs to God alone: lovers of wisdom or philosophers is their modest and befitting title." So speaks Socrates in Plato's Phcedrus of the genuine teachers of mankind, who, whether they be poets or law- givers or dialecticians like Socrates himself, know what they are talking about, and can distinguish what is really good from what is only apparently so, preferring what can be shown to be true to what is merely plausible and attractive. The word Philosophy has in the course of its long history been used now in a wider, now in a narrower sense; but it has constantly stood for inquiry not so much after certain particular facts as after the fundamental character of this world in which we find ourselves, and of the kind of life which in such a world it behoves us to live. Sometimes a distinction has been drawn between natural and moral philosophy, ac- cording as attention is directed to the world, or to our life uv it. In English books of a 8 A HISTORY OF PHILOSOPHY hundred years ago " philosopher " more often than not meant a " natural philosopher," and " philosophy " what we should nowadays call " natural science." This may be explained by the fact that it was at that time a prevalent view in this country that, apart from what could be learned from a supernatural revelation, the inductive and mathematical methods used in the natural sciences were the only means we had for discovering the nature of the world; while (apart again from duties prescribed by supernatural authority) it was man's chief task to be, in Bacon's words, the " minister and interpreter " of that " Nature " whose ways by those methods he endeavoured to search out. On the other hand, in popular language a " philosopher " often means no more than a person who in the conduct of his life is not at the mercy of circumstance. It is, no doubt, suggested that this is so because he has come to know the sort of world he has to do with, and so is not to be taken by surprise, whatever happens to him; yet the stress is laid rather on his behaviour than on the knowledge which has made it possible. Nowadays, we do not so commonly speak of " natural philosophy " as of " natural science " ; and an astronomer or a physicist, a chemist or a biologist, we should not call a philosopher, unless, over and above his special researches, he were also to engage in some PHILOSOPHY AND ITS HISTORY 9 speculation as to the fundamental nature of the one world in which there is mind as well as matter, unity as well as multiplicity, individuality as well as general laws, and were to put to himself such questions as these : How are matter and mind mutually related? How can what is one be also many, and what is many be also one ? What is an individual ? How can what is not individual be real ? and yet how can we describe any individual at all except in terms which might at any rate be applicable to other individuals as well? Such questions may be provoked by the investigations of the natural sciences, but cannot be decided by the methods used in those investigations. So long as a scientific investigator does not raise questions of this kind, he cannot, in our sense of the word, be called a philosopher ; though he may perhaps be so called, if, having raised them, he arrives after consideration at the conclusion that they are unanswerable and therefore not worth raising again. - Philosophy, says Plato, begins with wonder ; and, certainly, no kind of animal could learn to philosophize but one whose nature it was not to take things as they come, but to ask after the why and the wherefore of each, taking for granted that each has a why and a wherefore, and seeing in whatever happens to him (though he might not put it in this language) A 2 10 A HISTORY OF PHILOSOPHY no isolated fact, but an instalment of a single experience, a feature of a single encompassing reality, within which all else that had hap- pened or might happen would also be included. But we should hardly call this wonder or curiosity by the name of Philosophy until it had passed beyond the childish stage at which it could find satisfaction in mere stories, such as we find in the mythologies of all nations, which explain the origin of the world on the analogy of processes familiar to us as happen- ing within the world, but which we cannot conceive as taking place outside of the world. As Prof. Burnet has observed (Early Greek Philosophy, p. 10), the real advance made by the men whom we reckon as the founders of European philosophy " was that they left off telling tales. They gave up the hopeless task of describing what was when as yet there was nothing, and asked instead what all things really are now." The men of whom he is here speaking are the members of a school of inquirers who in the sixth century before our era flourished at Miletus, a prosperous city founded by Ionian Greeks on the coast of Asia Minor. It is with these men that our history of philosophy must begin. It is doubtful whether a philosophy properly so called, that is a systematic inquiry into the true nature of the world, set on foot merely for the sake of knowing the truth about PHILOSOPHY AND ITS HISTORY 11 it, can be shown to have originated anywhere independently of the ancient Greeks. Speaking of social life, Mr. Marett has said (Anthropology, p. 185) : "To break through custom by the sheer force of reflection, and so to make rational progress possible, was the intellectual feat of one people, the ancient Greeks; and it is at least highly doubtful if, without their leader- ship, a progressive civilization would have existed to-day." To the same people we owe, in like manner, that disuse of mere customary repetition of traditional explanations of the world's origin and structure, in favour of free speculation and investigation, which has made possible science and philosophy, as we now understand those words. Hence we are justi- fied in beginning our history of philosophy with the earliest group of Greek thinkers with whose theories we have any acquaintance. And even were there better evidence than there is of the existence of a genuine philo- sophy wholly independent of that which arose among the Greeks, it would still be impossible within the compass of the present book to attempt more than a description of that succession of thinkers who stand in a direct historical connexion with the development of modern European thought and knowledge; and the first in that succession are undoubtedly the ancient Greek philosophers. With the Greek philosophers, therefore, our 12 A HISTORY OF PHILOSOPHY history will begin. From their time onward to our own, there has been carried on within the sphere of European civilization a constant discussion of the kind of problems which we call philosophical, with a conscious reference to the conclusions reached by the chief Greek thinkers. This discussion has been at differ- ent times carried on more or less actively, more or less freely, more or less strictly within the lines laid down by its originators. There have been, as Bacon has said, waste and desert tracts of time, wherein the fruits of civilization, philosophy among them, have not been able to flourish. During these the discussion of philosophical problems has flagged; those who carried it on at all have but repeated the old arguments, and even of the old arguments themselves many have been forgotten or misunderstood. Again, the discussion has not always been carried on with perfect freedom, without fear of the issue, " whithersoever," to use a phrase of Plato's, " the argument may lead us." It has sometimes been supposed that a super- natural authority has on certain points en- lightened us with information which we could not contradict without committing the sin of disloyalty to a divine teacher. Sometimes, again, the very increase of knowledge as to the views of earlier philosophers has hindered those that came after from thinking questions PHILOSOPHY AND ITS HISTORY 13 out for themselves. Sometimes, on the other hand, new experiences, religious, moral, politi- cal, economic, scientific, aesthetic, have given a new direction to men's thoughts, and turned their attention away from the teaching of their predecessors to the facts; whether to facts which those predecessors had also had before them, or to others which had not been within their ken. At such times there has often been loss as well as gain. Mistakes which had long ago been corrected have been revived; and old confusions have been given a new lease of life under new names. Thus, this History of Philosophy, which we shall attempt to summarize, although it is the history of a discussion constantly carried on from the sixth century before the Christian era to the twentieth century after it, is not the history of a discussion in which every point made is made once for all, or every step taken is a step forward. Rather, it is the history of a discussion subject to interruption by practical affairs, interspersed with digres- sions more or less irrelevant to its main topic, conducted now slackly and now keenly, by disputants of very various abilities. Yet, when we survey it as a whole, we shall find that it is a discussion in which a real progress can be detected; and in which even inter- ruptions and digressions have proved refreshing and suggestive. 14, A HISTORY OF PHILOSOPHY CHAPTER II PLATO AND HIS PREDECESSORS THE problem upon which the philosophers of Miletus fixed their attention was that of change. Things were always coming into being and passing away, and yet they did not come from nothing, or pass away into nothing. The spectacle of the world was not a spectacle of new beginnings and utter vanishings; it was, rather, a spectacle of perpetual trans- formation but transformation of what? What was this one thing which took so many various shapes? That was the question which the earliest Greek philosophers set themselves to solve. The oldest of them whose name has come down to us, Thales, said that it was water. The next, Anaximander, said that it was a boundless or infinite substance out of which are segregated, so to speak, the different sub- stances with which we have to do ; not only water, which Thales had supposed to be the primary matter, but fire, which is its opposite and ever wages against it a truceless war. The third, Anaximenes, identified this primi- tive substance with air, or rather with mist or vapour, which could either be rarefied and heated into fire or condensed and cooled into water. All these three philosophers were PLATO AND HIS PREDECESSORS 15 citizens of Miletus, and all flourished in the sixth century before our era. Early in the next century, in the year 494 B.C., the in- vading Persians destroyed Miletus, and the Milesian school came to an end in its original home. But, at the not far distant city of Ephesus, there was then living a philosopher who must be reckoned as the successor of the Milesians. This was Heraclitus, whom later tradition called the " weeping philosopher," because, it was said, he always found in human life matter for tears, whereas Democritus (of whom we have yet to speak) found rather matter for laughter. Heraclitus saw in fire the primary sub- stance. Do we not see how flame is per- petually nourished by fuel, and how it perpetually passes into smoke ? The swiftness of flame, moreover, is so great that we may without absurdity think that man's swift thought is of like nature with it; and the confusion introduced into our wits by over- much liquor may seem to confirm the sus- picion. " The dry soul is the best," he said; and when we speak nowadays of the " dry light of science," the phrase is an echo of this ancient theory. The mind in ourselves is, then, a part of the eternal fire; and to this eternal fire can thus be attributed the power of thinking which characterizes our minds. But the great importance of Hera- 16 A HISTORY OF PHILOSOPHY clitus in the history of philosophy is not due to this new answer of his to the old question about the primary substance. It is due to the stress which he laid on the unceasing process of flux or change in which, as he held, all things were involved. As the hymn compares Time, so Heraclitus compared the course of nature to "an ever-rolling stream." You cannot step twice, he said, into the same river; for the water into which you first stepped will by now have flowed on, and other water will have taken its place. Now, it is easy to see that this doctrine of a universal flux involves very serious consequences for any one who should, above all things, desire knowledge. For how is knowledge possible if there is nothing that abides as it is; if, as soon as any statement is made, nay, before it is out of the speaker's mouth, it has ceased to be true? It was said that consistent Heracliteans renounced speech, and took to pointing instead. They criticized, we are told, their master Heraclitus himself as not having gone far enough in his saying that a man could not step twice into the same river ; for, said they, he could not do it once, since not for one instant did it remain the same river. It was to a certain Cratylus, who flourished a hundred years after Heraclitus himself, that these rigorous deductions from the doctrine of the universal flux are attributed; PLATO AND HIS PREDECESSORS 17 and of this Cratylus Plato (b. 427, d. 347) was in his youth a disciple. What he learned from this teacher concerning the flux in which all such things as can be perceived by the senses are involved, and concerning the con- sequent impossibility of really knowing them, stirred him up, it would seem, to seek else- where for something which should not be thus ever in process of becoming something else, but should admit of being known to be, essentially and permanently, of a certain nature. We must here note that Plato took the flux of Heraclitus to involve only such things as the senses could apprehend. This was because Heraclitus and his contem- poraries had recognized no reality which was not corporeal. They were not, indeed, materialists, in the sense in which that word implies the express denial that there is any reality which is not corporeal ; for no definite suggestion that such a reality exists had yet been made. They had not drawn a distinc- tion which to us is apt to seem fundamental ; they did not deny to mind the property of filling space, which belongs to matter; nor did they deny to matter the property of thinking, which belongs to mind. To Hera- clitus the soul could be dry, and fire could be wise. In what direction did Plato, in his dissatis- faction, a hundred years after Heraclitus, with 18 A HISTORY OF PHILOSOPHY the Ephesian philosopher's doctrine of the universal flux, and the consequences, so un- acceptable to an ardent aspirant after know- ledge, which Cratylus deduced from it, look for an abiding object whereof there could be a true knowledge? He looked, we are told, in a direction which had been indicated to him by Socrates. Socrates the Athenian (b. about 470, d. 399) was one of several among the greatest teachers of our race who have left no writings of their own behind them, and whose teachings are known to us only through the reports of others, reports which it is not always easy to reconcile with one another even in points of great importance. In the case of Socrates, the chief of these reports are a caricature by the comic poet Aristophanes in his play The Clouds, which was first represented when Socrates was about fifty years old ; a book of reminiscences (usually called the Memora- bilia) written after the death of Socrates by the distinguished soldier Xenophon, the leader and historian of the famous retreat of the ten thousand Greek mercenaries in 401 B.C. from the Persian highlands to the sea; and the Dialogues of Plato. Plato, like Aristophanes and Xenophon and Socrates himself, was a native of Athens. As quite a young man he had become a disciple of Socrates, and when, in later life, he composed the wonderful PLATO AND HIS PREDECESSORS 19 presentations of philosophical arguments in dramatic form which have made him immortal, he introduced his old master into most of them as the chief interlocutor, putting into his mouth (as we cannot doubt) not only what Socrates himself had said or might have said, but also the results to which, though Socrates himself might not have recognized them, Plato himself had been led in following up the trains of reflection which the talk of Socrates had started in his mind. Of these three reports, the earliest makes fun of Socrates as the centre of a rational- istic movement, which, to the old-fashioned Athenian conservatives whose mouthpiece the poet makes himself, seemed, in its en- couragement of novel theories about the nature of the universe and of a reckless delight in clever argument, no matter how unrighteous the cause which it was used to support, to be fraught with the utmost danger to religion and morality. In sharp contrast with this, Xenophon presents us with the picture of one whose death robbed all lovers of virtue of their most helpful friend, a man pre-eminent for piety and self-control, an enemy to all idle speculations which did not tend to make men good householders and good citizens. The more elaborate picture drawn by Plato helps us to understand how these two very different portraits might recall the same man to those 20 A HISTORY OF PHILOSOPHY who knew him. In an age of intellectual ferment none could be more fittingly taken as the representative of the spiritual unrest than this man of extraordinary originality and force, the effects of whose conversation could be compared to the electric shock given by the torpedo-fish, and whose personality, rough and ungainly though he was, had so strange an attraction for the most brilliant of the Athenian youth who in talk with him learned to be dissatisfied with commonplace ambitions and conventional acquiescence in things as they were. Yet those who kept company with him knew that he was no unprincipled dealer in idle and startling paradoxes; that, in carrying on as he did a rigorous cross- examination of all pretenders to knowledge, under which the most noted representatives of " advanced thinking " in his day were made to seem mere plausible praters about things of which they were ignorant, he was inspired by the conviction of a divine mission ; While the simplicity of his own life presented to the world a noble pattern of victorious self- control and cheerful freedom from the tyran- nous wants that make the worldly man's life a perpetual slavery. In Plato's Socrates we find at once the revolutionary impulse, pro- ceeding from an awakened spirit of intellectual adventure, which we miss in Xenophon's; and the moral inspiration which it was not in PLATO AND HIS PREDECESSORS 21 accordance with the purpose of Aristophanes to include in his picture of the arch-corrupter of ingenuous youth. It was as a corrupter of youth, and as one who denied his country's gods, that Aristo- phanes presented Socrates upon the stage; and it was in the same character that in 399 B.C., when he was over seventy years old, he was accused and sentenced to die by the drinking of a cup of hemlock. Very likely, he would not have been so condemned had he, according to the custom allowed by Athenian law, admitted a measure of guilt, and proposed for himself some lesser, yet considerable, punishment instead of the capi- tal penalty proposed by his prosecutors ; for, although a poor man himself, he had wealthy disciples, who would gladly have paid a heavy fine on his behalf. Nay, had he consented to let his friends contrive his escape from prison, it is likely that it could have been effected without difficulty, and he could have spent the remnant of his days in a comfortable exile. But he would not admit that he had deserved any penalty; though under protest he 'so far yielded to his friends' entreaty as to name a fine (of no great amount), he plainly said that the treatment which was really due to him was an honourable provision at the public expense as a benefactor to his country; and when, after this refusal to declare himself 22 A HISTORY OF PHILOSOPHY against his conscience to be anything but innocent, the death sentence was pronounced, he would not by evading it turn his back in his old age on the duty, which he had ever thought and practised, of filial submission to his country's laws. Of the closing scenes of his life Plato has given us in his Apology, Crito, and Phcedo a picture which, as a pattern of piety and courage in the presence of death, is one of the spiritual treasures of our race. It would seem that neither of the two charges brought against him was true in its most obvious sense; but there was plausi- bility in both. What were the grounds alleged for the accusation of irreligion, we have no distinct information. But although, according to our evidence, religious noncon- formity was no characteristic of Socrates, yet even apart from probable failure in the popular mind (as in the Aristophanic cari- cature) to distinguish between various forms of the movement of free thought, of which Socrates was the most conspicuous figure, and the consequent attribution to him of a destructive rationalism with which he had little sympathy his talk of a divine mission and of supernatural warnings peculiar to himself might well suggest that he was not content with the religion of his neighbours. Possibly also there were rumours of friendly relations existing between him and circles PLATO AND HIS PREDECESSORS 23 known to profess initiation in religious mys- teries or secret rites unconnected with the State system of worship. As to the cor- ruption of the youth, we may well believe, on the word of those who knew the facts, that the remarkable influence exercised over boys and young men by Socrates was one which made for righteousness and self-control, and yet admit that suspicion might naturally be aroused by the intimate association with him in their youth of men (such as Alcibiades and Critias) who had afterwards become notorious for the unscrupulousness and disloyalty of their political careers. Nor, indeed, can the dissatisfaction with the failings of his own state, which, loyal citizen as he was alike in his life and in his death, Socrates certainly felt and expressed, have counted for nothing in unsettling his disciples' allegiance to the standards recognized by their fellow country- men. It is noteworthy that, of his two chief apologists, Plato in many respects preferred to the constitution of Athens that of her rival Sparta, and Xenophon actually passed from the Athenian into the Spartan service. There are few among the celebrated men of history with whose personal appearance and habits we are so well acquainted as with those of Socrates. Some reference to these is not out of place even in so brief a history of philosophy as this; for in his person Plato, 24 A HISTORY OF PHILOSOPHY the greatest of writing philosophers, saw incarnate the ideal of the philosophic life. The contrast between his ugly exterior and the nobility of his spirit profoundly impressed a people like the Athenians, who were peculiarly susceptible and none more so than Socrates himself to the charm which is added to intercourse with a beautiful soul when it is housed in a beautiful body. In a famous passage of Plato's Banquet, Alcibiades com- pares his master to an image of the grotesque and pot-bellied satyr Silenus, which, when opened, is found to contain the beautiful figure of some god. The same dialogue gives us a vivid account of Socrates' extraordinary powers of endurance and self-control, which enabled him to endure without defeat alike the utmost rigours of military service and the sharpest temptations of the flesh; to remain at the end of a drinking bout, in which he had by no means abstained from his share of the wine to which his companions had suc- cumbed, as sober and clear-headed as ever; and during a campaign to meditate in com- plete abstraction from all surroundings through a whole winter's day and night. This singular capacity of rising above the weaknesses of other men was united in Socrates with a social charm, a keen humour, a critical perspicacity, which made it impossible to disregard him as an inhuman ascetic or an unpractical dreamer. PLATO AND HIS PREDECESSORS 25 His imposing personality, unaided as it was by rank or wealth or beauty, presented philosophy to the world in her native dignity ; and the would-be philosopher, whether at- tracted more by the " rigour of the game " of thinking things out, or by the desire to be independent of the changes and chances of this mortal life, could find either ideal exempli- fied in the great Athenian. We have now to consider how it was that Socrates (as has been said) showed Plato the way out of the doubt of the very possibility of true knowledge into which he had been plunged by his assent to the doctrine of Heraclitus that all things were in a perpetual flux. We have seen that Socrates was con- temporary with, and was regarded at Athens as representative of, a widespread rational- istic movement. The leaders of this move- ment were a class of men of whom we generally speak collectively as " the Sophists." The word " sophist," which we now use to signify a dishonest reasoner, meant properly no more than a professor of wisdom or knowledge. To his contemporaries, Socrates was himself a " sophist " ; and it is as the arch-sophist that he is caricatured by Aristophanes. But the title was one which Socrates did not care to claim. To the possession of wisdom he made no pretensions, only to the love of it ; when an enthusiastic disciple told him on the authority 26 A HISTORY OF PHILOSOPHY of the Delphic oracle that he was the wisest of men, he was seriously perplexed; and the constant cross-examination, to which he pro- ceeded to devote himself, of all pretenders to wisdom that he could find, he represented as undertaken from a sense of religious duty, in order to satisfy himself as to the meaning of the God. The result of this cross-examination was a conviction that these pretenders knew no more than himself ; and he concluded that he was, as the oracle had said, wiser than other men, not because he knew more, but because he was aware, as they were not, of his own ignorance. Further, it seemed to him that, even if one had possessed wisdom, it would have been wrong to make of it a means of worldly profit. The profession of it in this way by his contemporaries had led them to prefer popularity to thoroughness. Living by the applause of the public, they must needs say what the public liked. The Public itself was the great Sophist, in the bad sense which his disciple Plato probably learned from him to give to the word, and which it still bears, of one who loves gainful plausibility rather than the genuine truth, which makes men free indeed, but not rich. He himself charged no fees for his instructions, and remained a poor man to the end. Hence, while the world at large took Socrates for a notable sophist, his followers PLATO AND HIS PREDECESSORS 27 came to regard him as the great antagonist of those who could properly be so called. These were men who, for the most part, had detached themselves from civil ties and wandered from place to place (unlike Socrates who, except on military service, never left Athens), gathering pupils who hoped to learn from them the arts of persuasion by which they might achieve success in their respective commonwealths. Men associated with their instructions the spread of a notion that the distinction be- tween right and wrong was not natural and permanent, but merely conventional, so that (as seemed, indeed, to be the case in view of the great variety of customs obtaining in different places) what was right in one region was wrong in another, and what was wrong under one set of circumstances became right when they were changed. It appeared im- possible any longer to identify (as simple old- fashioned folk were apt to do) right conduct with a particular set of customary or tra- ditional rules of behaviour, without being brought up at once against exceptional cases, in which the rules would not hold. This disquieting criticism of familiar ways of thinking could not be permanently checked by refusing to consider these exceptional cases. It was the distinctive feature of Socrates' teaching that he sought by further thinking and discussion to heal the hurt that 28 A HISTORY OF PHILOSOPHY thinking and discussion had done to simple faith in moral principles. This is right, or just, or brave here and now that there and then the other under those other circum- stances. Well and good ; but, if these state- ments are to have any meaning at all, right, just, brave must mean the same in each case. We may, for example, admire some man's honesty on some particular occasion; yet we should readily admit that we might be mistaken as to his motives, and that a fuller acquaintance with them might make it plain that there was nothing to admire. I thought (we should say) that he was honest ; but I fear I was mistaken. But we should resent the suggestion that we did not know what honesty was ; and, if we did not, how could we recog- nize it or even mistakenly think that we recognized it, in the particular case before us ? Hence our great business is to make clear to ourselves what we mean by these predicates (as they are called in logic, a science which owes much to these discussions) right, just, brave and the rest and to fix our meaning by a definition of each. It was this assertion by Socrates that there were permanent natures of justice, courage, and so forth, which it was the purpose of framing definitions to express, that showed Plato a way of deliverance from the doubts about the possibility of knowledge induced PLATO AND HIS PREDECESSORS 29 in him by the Heraclitean doctrine. For these natures were not objects of the bodily senses. What I perceive with the bodily senses on each occasion is only a particular man or action in which I think I recognize a nature which I know ; but this nature itself is an object, not of the senses, but of the under- standing. There is, then (so Plato concluded), beside the world of sensible things, for ever shifting and changing, and even at once great and small, hot and cold (for such terms are always relative), so that what is said of them at any time is never lastingly, never wholly true, another world of eternal forms or natures, about which we can have knowledge properly so called, a knowledge which is pre- supposed in the very opinions which are all we can have about the things which are apprehended by the bodily senses. For I cannot even mistake another man for you, unless I know you; nor can I guess, even wrongly, that such and such an act or man is honest, unless I know what honesty is. Socrates (we are told) had confined his sug- gestions on this subject to the sphere of morality, that is to such definable natures as have been already instanced, to which it concerns all men to conform their actions, and with which it is thus of practical impor- tance that they should be familiar. Plato, at any rate, carried the line of thought further, 30 A HISTORY OF PHILOSOPHY as he might easily do. For as, in order to think that this or that act is just, we must know what justice is; so, also, in order to think that the line A B is straight or that the lines A B and C D are equal, we must know what straightness or what equality is. Here, too, there is a permanent nature, apprehended by the understanding, not by the senses, which does not become, even while we speak of it, something else than what we are saying that it is. These permanent natures, discovered by Socrates in his efforts to find an abiding object for our moral judgments, which should not be at the mercy of custom and circum- stance, became the corner-stone of Plato's philosophy, and are called by him Forms or, to use the Greek word, Ideas. This word Idea is familiar to us; but in modern English it usually means something very different from what it meant to Plato. With us, it means something in our minds which may or may not correspond to an independent reality outside of them. With him, it meant the form not the mere out- ward shape, but the inner essential structure or nature of anything, which made it the kind of thing it was. Even when it was what we call a corporeal or material thing^ it was not the senses (which have only to do with super- ficial appearances) that could take account of this inner essential nature. The Form or PLATO AND HIS PREDECESSORS 31 Idea is, therefore, the proper object, not of the senses, but of the understanding. Yet we must be careful to remember that this does not mean that it is what we call a " notion " or " concept," something which has its being only in the mind ; it is that of which we have a notion or concept, but which does not by any means depend for its existence upon our thinking of it. We may help ourselves to remember this by recalling the way in which the modern man of science commonly regards the ." laws of nature " which it is his task to discover. He does not think of them, of course, as bodily substances which he per- ceives or might perceive with his senses ; but neither does he think that their existence depends upon his or any one being aware of them. His " science " consists in ascertaining and describing what they are. If his senses report anything inconsistent with an ascer- tained law, he is more inclined to suspect that they are deceived than that the law is not what his understanding (starting, no doubt, from experiences got by means of the senses) has made it out to be. It would not, indeed, be correct to say that what Plato meant by Ideas is just what the modern man of science means by " laws of nature " ; but the con- sideration of our attitude towards the latter may help us to understand Plato's view of the former. The Ideas of Plato are the 32 A HISTORY OF PHILOSOPHY eternal natures, whatever they be, which constitute the inner reality of the universe, and which alone can be objects of true know- ledge. They are not perceptible by the senses ; they can be apprehended by the understanding only. But, just as we com- monly take the things which the senses v per- ceive to have an existence quite independent of our perception of them, so the Platonic Ideas are no product of the mental activity by means whereof we apprehend them; they are rather its presupposition. It was said of Bacon that he " would light his torch at every man's candle." The saying is eminently true also of Plato, whose genius found stimulus and suggestion in the teaching of many predecessors beside Heraclitus and Socrates. Thus, he owed much to the Pytha- goreans, with some of whom his master Socrates seems to have lived on terms of friendship. This school of thinkers took their name from Pythagoras, who was born in the middle of the sixth century at Samos, an island off that coast of Asia Minor where the earliest Greek philosophers taught, but who spent the latter part of his life among the Greek colonies to which Southern Italy owed its title of Magna Graecia, or Greater Greece. * Pythagoras left, it would seem, no writings behind him, but was the founder of a religious society, which in one city of that region, PLATO AND HIS PREDECESSORS 33 Crotona, succeeded in acquiring for a time the supreme control of the commonwealth. The Milesian school of thinkers had been at no pains to connect their philosophy with the popular religion; though they spoke of " gods," they meant by the words not con- scious beings to be worshipped, but merely the principal elements of the system of material nature. But Pythagoras was the leader of a religious revival which, if, on the one hand, it brought into new prominence certain superstitious beliefs and practices of primitive, not to say savage, origin, on the other hand deepened the sense of individual dignity and responsibility by its doctrine of the immortality and transmigration of souls. He was at the same time, like the Milesians themselves, a man of science, and is reckoned as the founder of the science of geometry and as the discoverer of the musical octave. Among those who in Plato's day called them- selves Pythagoreans, there lived on both the tradition of mathematical and musical studies, and the tradition of a serious interest in the destiny of individual souls. The latter tra- dition was connected with the speculations and fancies contained in certain books which passed under the name of the mythical musician Orpheus, to whom legend attributed a special knowledge of the secrets of the world beyond the grave. 34 A HISTORY OF PHILOSOPHY On both its mathematical and its religious sides, Pythagoreanism exercised a consider- able influence upon Plato. He was himself a great mathematician, and is said to have put this inscription over the door of his lecture* room : " No admission to any one ignorant of Geometry." His account of the Ideas, eternal natures which do not come into being or pass away, nor are in any way affected by the lapse of time, had been in many respects anticipated by the Pythagorean doctrine that the ultimate essence of reality was to be sought in Numbers. To this doctrine Pytha- goras' discovery that musical harmonies de- pend upon musical proportions perhaps first gave occasion; and the progress of natural science, which was perpetually extending the range of exact measurement, and describing in mathematical formulas an ever-increasing number of natural phenomena, would con- tinually confirm it. Among the eternal natures which Plato called Ideas must certainly be included many natures beside those of the numbers and figures with which the mathe- matician deals; yet we know that Plato himself, and still more the first generation of his followers, were wont, in the spirit of the Pythagoreans, to speak of them all, whenever they could, in mathematical language. A like relationship to that which connects Plato's doctrine of Ideas with the Pythagorean PLATO AND HIS PREDECESSORS 35 doctrine of Numbers connects his doctrine of the Soul with the Pythagorean speculations on its immortality and transmigrations. For Plato, the Soul is the link between the eternal and unchanging world of the Ideas, which by its understanding or reason it is able to appre- hend and survey, and the world in which birth and death, death and birth, succeed one another in a perpetual cycle. Of the movement and change which characterize this inferior world, the living Soul is, according to Plato, the cause; for it is the only thing, he holds, that we can think of as spontaneously moving itself and originating movement in other things : bodies can only move when pushed by others, or when, as in living beings, set going by a soul or principle of life within them. Plato could not think but that the Soul must share the eternity of those Ideas in the apprehension whereof lay its essential nature and function as a mind or intelligence ; while, although the individual beings, which in the course of the cycle of birth and death are incessantly coming into existence or passing away, can lay no claim to permanence, the cycle itself and the Soul which is the principle of its perpetual movement are with- out beginning or end. But this immortal or eternal Soul is the Anima mundi, or Soul of the world; it is not your individual soul or mine; for these belong to the cycle of birth 36 A HISTORY OF PHILOSOPHY and death, and include, along with the appre- hension of the eternal Ideas, all sorts of imaginations and desires which have their origin in the perishable bodies with which our souls are associated. What, then, did Plato hold concerning the origin and destiny of your soul or mine? In trying to answer this question, it is necessary to remind ourselves that, in Plato's view, Philosophy is the apprehension of eternal and unchanging natures, and the only questions which she can properly be called upon to answer are questions about these, and not about the past history or future prospects of anything which is affected by the lapse of time. There must be, of course, a true answer to questions of this latter kind; but all that Philosophy can say of them is that neither of the past nor of the future can anything be true which is not in accordance with what she knows of the eternal and un- changing natures. Hence, in cases where there is at hand no historian or prophet who can tell us what has been or is to be, we must be content to fashion for ourselves a " myth " or story, of which it is required only that it should nowhere contradict what we know to be the eternal nature of things. The Dialogues of Plato contain a number of such " myths," which suggest answers to questions of just this sort questions about the creation of the PLATO AND HIS PREDECESSORS 37 world, or the origin of society, or the destiny of the individual soul. For these last, Plato drew upon the traditions connected with the name of Orpheus, and the kindred specula- tions of Pythagoras and his followers. There is no reason to doubt that, while giving rein to his imagination in the details, he really believed as a matter of probable opinion, though not (since it concerned the world of vicissitude) as a part of the knowledge attainable by philo- sophical discussion properly so called, that even individual souls never wholly perished. The apparent recognition of truth when presented to the individual for the first time as when we say of the solution of a mathe- matical problem, " Yes, I see that is right " seemed to him best explained by the sup- position that one is really recalling what had been known to us in a previous state of existence, but since forgotten. Perhaps every soul passed through a series of re-incarnations, in which the nature of each new birth was determined by the moral character acquired in the one preceding. A somewhat similar belief forms an important article of the Buddhist creed; which, however, sets before its followers the hope of an ultimate deliver- ance, through the accumulation of merit in successive lives, from the necessity of being born again at all. Plato, since he does not regard life in Buddhist fashion as necessarily 38 A HISTORY OF PHILOSOPHY an evil, does not speculate upon such an escape from the cycle of birth and death. But he is earnestly concerned to insist that the eternal nature of things requires the destiny of any soul to be decided according to its deserts. The doctrine that the gods can be bribed by money spent on sacrifices to let the sinner off the consequences of his sin excites his strongest indignation; and, when he uses the language of the Orphic poems about an initiation which has the promise of a better life to come, he makes it plain that he has in mind no admission to assist as performer or spectator at external ceremonies, but the entry upon the life of a true philosopher, in which the eternal nature of goodness is understood and the conduct of life conformed thereto. Beside the Pythagoreans, another school of philosophers, which had arisen later on in the same part of the Greek world, must be reckoned among those to which Plato was specially indebted. This was the Eleatic school, so called from the south Italian town of Elea or Velia, of which its first teacher, Parmenides, was a citizen. Plato introduces him, in a dialogue which bears his name, as visiting Athens when Socrates was a very young man, that is, in the middle of the fifth century B.C. In dealing with the same problem as Heraclitus, Parmenides took \ PLATO AND HIS PREDECESSORS 39 exactly the opposite line. Movement and change, which Heraclitus saw everywhere, he will have to be nowhere. Wherever we seem to find them, we are victims of an illusion. If we think of what we mean by moving, whatever moves must move into some un- occupied space. It is true that it may do this by pushing out some other occupant; but if there were no unoccupied space any- where, no movement could begin at all. Parmenides seems to have considered that to speak of a space where there was nothing at all would imply that " nothing " was " something." This appeared to him to be unthinkable; and he was sure that nothing unthinkable could be real; and, indeed, we do commonly assume that in making a thing intelligible to ourselves we are finding out what it really is. Hence, he did not shrink from saying that movement and change of every kind were illusory, and that what really existed must be one unchanging, unmoving thing, the same everywhere and in every direction, without any distinction of parts in its unbroken unity. Our senses present us, it must be admitted, with a very different sort of world; but the senses, which, as all men admit, often deceive us, are not to be trusted ; we must correct them by our reason, which can make nothing of a world of change. We can understand how Plato, who himself 40 A HISTORY OF PHILOSOPHY had found no satisfaction for the aspirations of his reason in the theory of a world wherein was nothing but change, would be disposed to sympathize with Parmenides. Indeed, in his own doctrine each single Idea or eternal nature stands to the many sensible things or facts, in which it is as it were repeated over and over again, although mixed up with other and even opposite characteristics, very much as the one Reality of Parmenides stands to the illusory world of manifold changing and moving things which the senses put before us. But in Plato there is not only one eternal nature, but many; there is, therefore, a multiplicity and difference in the real and intelligible world as well as the world of con- fused appearance which the senses perceive; and, moreover, in Plato this world of appear- ance is not a mere illusion; it is "between being and not being " ; it is really there before us, though it seems to be what it is not ; it is not, as Parmenides had made it out to be, sheer " not-being," without reality of any kind. Parmenides' denial of the reality of so ob- vious a fact as movement no doubt seemed to his contemporaries highly paradoxical. A pupil of his, Zeno by name, sought to defend his master's paradox by showing that, when we try to understand this obvious fact of movement, we find it at least as para- doxical as Parmenides' doctrine that there is PLATO AND HIS PREDECESSORS 41 really no such thing. For example, if the swift-footed Achilles should run a race with a tortoise, it would at first seem easy to show that he must soon outstrip it. But let us see. Suppose Achilles to run ten times as fast as the tortoise, and the tortoise to have a hundred yards start. When Achilles has covered the hundred yards, the tortoise will be ten ahead ; when Achilles has covered the ten, it will be one yard ahead; when Achilles has covered the one yard, the tenth of a yard ; and so on, to infinity. Another of Zeno's puzzles is that of the moving arrow. At any instant of the time during which it is in motion, it will be at rest in a particular place ; a cinematograph film might represent its flight by a series of instantaneous photographs in each of which it would so appear. When, then, does it move from one of these successive positions to the next ? These and similar puzzles have proved of much importance as helping to show that extension in space and duration in time must both be regarded as continuous, and not as discrete, quantities; that is, they are not made up of points and instants as a number is made up of units. Such a discussion of familiar notions, in- tended to bring out their difficulties by seeing what will follow if one admits the position of any one with whom one is arguing, is what the Greeks called dialectic, and of dialectic B 2 42 A HISTORY OF PHILOSOPHY Zeno was considered the inventor. Socrates was a master of this art, and Plato was so convinced that it was the proper method, not of finding out particular facts, but of getting to the bottom of whatever view it brought forward, that he sometimes used the word dialectic for the science of the ultimate nature of reality, which we call Philosophy. In his Dialogues, the various positions from which he starts are put dramatically into the mouths of men who might naturally hold them. His earlier dialogues are suggested by the argu- ments of Socrates about the meaning of justice, courage, piety, and the like ; in the later, where he is often concerned with more abstract con- ceptions, such as unity, identity, difference, and so forth, he is conscious that he is engaged on problems more like those which occupied the Eleatics. Accordingly Socrates is no longer unquestionably the central figure of the piece ; Parmenides himself or an " Eleatic stranger " takes a part in the discussion no less important than his. One more predecessor of Plato must here be mentioned Anaxagoras, who lived in the earlier half of the fifth century B.C. He was, like the Milesian philosophers before him, an Ionian Greek of Asia Minor, but lived for some years at Athens as the friend and adviser of the great statesman Pericles. He was at last, however, forced to leave that city, PLATO AND HIS PREDECESSORS 43 for the boldness of his speculations concerning the sun and moon, which he regarded not as divine beings but as bodies made of the same kind of stuff as the earth under our feet, had incurred the suspicion of the Athenian demo- cracy. That democracy, then, as in the case of Socrates a generation later, showed itself impatient of freedom of thought on subjects touching the religion of the State. Especially this was so when, as with both Anaxagoras and Socrates, this free thinking was practised in circles the distinction of whose members rendered uneasy a sensitive public, ready to scent political danger in any kind of social or personal superiority whatever. The early attempts to explain the world about us by pointing to some single primitive substance, of which one could assert that everything at bottom was just this, had failed to account for the variety which the actual world exhibits. " It takes," as the English proverb says in another connexion, " all sorts to make a world." How are we, then, the better off for an explanation which mentions only one sort? Anaxagoras allowed that things were originally of different sorts ; but these different sorts were, he thought, all at first mixed up together in a confused mass or chaos, from which they were afterwards sorted out, and a proper place assigned to each. To what was this sorting out to be ascribed ? Anaxagoras 44 A HISTORY OF PHILOSOPHY replied: "To Mind or Intelligence." This answer, we are told, made, when he first met with it, a great impression upon Socrates. It seemed to him a new and a more hopeful way than those suggested by other thinkers of explaining the wonderful order which we find in the world. To use an illustration of later date, if we were to find on the sea-shore a thing of complicated structure, the like of which we had never seen before, our curiosity would be satisfied if we learned that its struc- ture enabled it to show the time of day, and that it was made by an intelligent human being who had designed it for that very purpose. Socrates, indeed, complained that Anaxagoras, having spoken of Intelligence as the general cause of the order of the world, did not go on to explain the details of its arrangement by the purposes they served. He tried to do this for himself, and was thus among the earliest of those who have set them- selves to trace as best they could, in the adapta- tion of the bodies of men and animals to their mode of life, evidence that they are the handiwork of a wise and beneficent creator. Plato was in close sympathy with his master here. When we are puzzled by anything which we observe, we try to find some way of regarding it which will puzzle us no longer, and at the same time show us why it puzzled us before. We trust our intelligence more PLATO AND HIS PREDECESSORS 45 than our senses, and are ready to say that the thing before us is really what we can under- stand, though it may still look very different. It is thus that we rise from the world which the senses perceive to the world of Ideas or eternal natures, wherein is no inconsistency or contradiction, but all is intelligible. There are, as we have seen, many such Ideas or eternal natures. Have they nothing to do with one another ? The mind in quest of the intelligible will not be content to think so. It can only rest when it has found them all to be members of a single system, in which each has a place assigned to it by a principle which determines the function, the good of each. The vision of such a principle, an " Idea of the Good," is the ultimate goal of our intel- lectual endeavour. Such a principle can be no mere creation of our fancy, unless the long quest to which is due the attainment of all our knowledge, whether that by which we distinguish the common objects of everyday life from mere reflections, shadows, imitations of them, or the exacter knowledge which we call science, has from the first been all astray. For we have always assumed that only what satisfies our intelligence can be real. And our intelligence cannot be satisfied unless it be assured that, in the last resort, it is no accident that things are intelligible, but that, if we have discovered what they are by 46 A HISTORY OF PHILOSOPHY following this clue, our justification is that Intelligence, akin to the intelligence which has hitherto guided our search, is the ground at once of their being what they are, and of their being known to us as they are ; in other words, that there is immanent in them a divine plan, which is revealing itself to us, as, in the adventurous spirit of Socrates, we " follow the argument whithersoever it lead us." Since only through acquaintance with this universal plan can a sure foundation be obtained for that knowledge of the due place of each of the several functions the perform- ance of which make up the life of an organized community of men and except in an organ- ized community human beings cannot develop their spiritual capacities the rulers of such communities should, in Plato's judgment, be philosophers. In his greatest work, the Re- public, he has sketched the training which would provide the State with " guardians " so qualified. It is no merely intellectual training which he describes. It was characteristic of him not to think of the life of thought as something apart from the life of feeling or of will. The genuine philosopher will bring to the contemplation of the Supreme Goodness not only a mind trained in the exact sciences, but a passionate enthusiasm learned in the school of the love which beauty kindles in the young, and an unselfish public spirit SUCCESSORS OF PLATO 47 ingrained by military discipline and by the habit of a comradeship in which a man (or a woman, for Plato's " guardians " may be of either sex) may call nothing his or her own not even (strange and monstrous as it seems to us) wife or husband, parent or child. When Plato died in 347 B.C., he left behind him at Athens a college of his own foundation, called by the name already belonging to the place in which it was established, the Academy. This institution, whose name has come to be a synonym for " learned society," became from the first a centre of scientific and philo- sophical activity. It was the nucleus of what in a later age developed into what we should call a university, and its corporate existence lasted until the confiscation of its endowments by the Emperor Justinian in A.D. 529. Among the young men who studied at this college under the founder himself, the most celebrated was he who became that founder's chief critic and the great rival of his fame, Aristotle of Stagira in Thrace. CHAPTER III ARISTOTLE AND OTHER SUCCESSORS OF PLATO IT has been said that every one is born either a Platonist or an Aristotelian ; and the names of the two great Greek philosophers 48 A HISTORY OF PHILOSOPHY are often opposed to one another as repre- sentative of two contrasted and incompatible types of mind. Plato, it is thought, stands for the " mystical " or " idealistic " type, which supposes the facts of life to mean more than meets the eye or ear, and overleaps the bounds which nature has set to experience, in order to speculate on things which are guessed to lie beyond. Aristotle, on the other hand, is taken for the champion of a more cautious method, which, holding fast by the rules of a strict logic and keeping close to the facts of experience, reaches positive results, verifiable by observation and experiment, and which shuns the regions of vague speculation in which the Platonist, it is said, loves to expatiate. As in Raphael's cartoon of the School of Athens, Plato points upward to heaven, Aristotle downward to the earth. A closer acquaintance with the great writers in question might probably shake the reader's confidence in the accuracy of this popular view. He^would find Plato at once a severer reasoner and a more practical moralist than it would suggest; while he might be led to doubt whether Aristotle's temperance in speculation and condescension to the ideals of ordinary men had not been exaggerated. Aristotle (b. 384, d. 322) was a member of Plato's college, but became dissatisfied with the style of thought and teaching which pre- SUCCESSORS OF. PLATO 49 vailed there, and left it to found a similar institution of his own, in a place called the Lyceum; whence what in England is called a " public school " is called to-day in France a Lyce. But, though he thus separated him- self from those who had been his fellow scholars, Aristotle always, in his philosophical writings, starts from the position of a Platonist, and proceeds to develop his own views in the form of a criticism of those Platonic doctrines with which he found himself unable to agree. Hence, the first impression made upon a student is that of a perpetual opposition to Plato; the fundamental agreement in many respects between the pupil and his master is less observed, because it is, naturally, less insisted upon. Aristotle agreed with Plato that the objects of knowledge, properly so called, were the permanent natures of things, which are apprehended not by the senses but by the understanding. These he called " Forms, 9 * as Plato had done; but, while Plato had employed almost indifferently two very similar Greek words with this meaning, one of which was " Idea," Aristotle rarely made use of this latter word, except when referring to the special views of Plato concerning them. Hence it is that the word " Idea " has in the tradition of philosophy become especially asso- ciated with Plato. Aristotle took exception 50 A HISTORY OF PHILOSOPHY to the language, used by Plato and by most of his school, which represented the permanent natures of beings in the world around us as though they existed separately from the individual things which " partook of " them or " copied " them. Plato himself had, indeed, been aware of the inadequacy of these ways of stating the relation of the many things which there may be of any one kind to the nature which we recognize in them all, and which we can consider by itself apart from any particular instance of it. We may call this relation " participation " ; but we do not suppose the nature in question to be parcelled out among the instances of it so that, of many beings that we call, say, " great " or " small," each should have only a part of greatness or smallness dealt out to it, as, when several men take refuge under one sail, each is covered by a different bit of it. Or we may call the relation of this common nature to the instances of it " imitation." But, if I suppose the fact that you and I are both men to be explicable only by saying that we are both copies of one pattern, of an archetypal man, we shall have next to explain the likeness of each of us to that same pattern by saying that there is some further pattern, from which you or I and the archetypal man are copied, and so on to infinity. Perhaps the best answer to these SUCCESSORS OF PLATO 51 difficulties would be that with the relation of a particular instance of a certain nature to that nature we are just as familiar as we are with the relation of a part to a whole or of a copy to its original. We do not under- stand any one of these the less because we cannot describe it in terms of another; or understand it the better because we try so to describe it. But if this was what Plato meant us to infer from the fact that he admitted the difficulties of such descriptions, while holding fast to his assertion that the natures of which there were many instances were yet real on their own account, he did not so plainly draw the conclusion as to make his followers re- nounce the questionable language about the particulars being copies of the common nature which he himself had sometimes used, or to satisfy Aristotle that this questionable language did not need to be decisively repudi- ated, if we were to reach a true comprehension of the relation of the common nature to the particular instances of it. Aristotle did not suppose, as many have done, that the common nature could be dis- missed as no more than a notion or concep- tion of ours. This suggestion is actually put by Plato, in his dialogue Parmenides, into the mouth of the youthful Socrates. Parmenides at once disposes of it by the pertinent question : "Is it a notion of nothing?" We should 52 A HISTORY OF PHILOSOPHY have, if we admitted it, to allow that the natural sciences, which deal almost wholly with characteristics common to many individuals, were a mere mind-play of ours, and could make no pretension to deal with realities independent of our minds. Aristotle, at any rate, did not deny that the Forms or per- manent natures of things were independent of our minds. But he distinguished in the nature of things characteristics which were substantial (such as humanity) from char- acteristics which were only attributive (such as greatness, whiteness, wisdom, and the like). The latter were only real as belonging to the former ; while of the substantial forms them- selves he held that only in our discourse were they ever separated from the individual beings whose essential natures they were. Each individual being, indeed, might be said to have its own " form " ; in the case of a man this is what we otherwise call his " soul." His body, considered apart from the soul or principle of life to which it owes the structure and functions which entitle it to be called a body, is the opposite of the " form " ; it is the " matter." When several things are of the same " kind " or " species " (Aristotle here uses the same word which we have hitherto translated by " form "), no statement of permanent scientific value can be made of one such thing, as a member of the species, SUCCESSORS OF PLATO 53 which cannot as well be made of another. The predicates in such statements, which will hold of many individuals, he called " uni- versals," as opposed to " particulars " ; and hence we often speak of Plato's Ideas, or Aristotle's Forms, or whatever corresponds to these predicates, as " universals." It is only, according to Aristotle, in the sublunary world that there are many indi- viduals belonging to one and the same species. This is because bodies -below the moon are composed of a material compounded out of four kinds of substance, earth, water, air and fire, the recognition of which as elements was due to Empedocles, a very influential fifth- century philosopher, whose home was Sicily, and who, according to a legend (which Matthew Arnold took for the subject of a well-known poem), threw himself into the crater of Etna, in order that so complete a disappearance might encourage the belief that he had been translated without dying to the company of the gods. These four elements, themselves due to combinations of what were regarded as the four fundamental qualities, hot with its opposite cold, and moist with its opposite dry, were tempered together in various pro- portions to form various bodies, which in view of the constant opposition between their constituents could have no lasting stability, and must therefore be perishable. Hence the 54 A HISTORY OF PHILOSOPHY multiplication of individuals, through the succession of which the species, though not the individual, could realize the immortality after which all things are consciously or un- consciously striving. In the higher regions of the universe, each individual heavenly body, being made not of this composite matter, but wholly of a superior stuff, the " quintessence " or fifth element, is imperishable, and is the sole individual of its kind, not needing to secure immortality by begetting another indi- vidual of the same nature as itself. This summary sketch will sufficiently show that it was chiefly to the phenomena of organic life that Aristotle's attention was directed; and it was to them, also, that he went for a clue whereby to explain what he held to be the eternal circular motion of the heavens. Where motion is due, as in inanimate bodies, to impact, the impinging body must itself have been moved by the impact of another, and so on for ever. But in living beings we find another kind of motion. Plato, too, had sought for the ultimate source of move- ment in a living soul which moved itself. But Aristotle did not think the motion of living beings could be strictly described as self-movement. Their movement has always a cause beyond itself which acts on them not by pushing their bodies, but by exciting their desires, and need not itself be in motion at all. SUCCESSORS OF PLATO 55 For desire may be of an object which does not reciprocate it, or is even unconscious of it. In the last resort, then, all motion must go back to an unmoved mover, who moves by exciting a desire which in turn brings about a movement of the living being in whom it is excited. And so, for Aristotle, " Tis love, 'tis love that makes the world go round." The unmoved mover of the universe is God. God, as supremely good, moves the world as the beloved moves the lover; but he does not reciprocate the love that draws all else toward him. The only activity which can be attributed to such a being, perfect and in need of nothing beyond himself, is that of knowledge ; and the only object of knowledge which is not unworthy of him is his own eternally perfect nature. God is not the maker of the world, which is itself eternal ; nor yet is he its soul ; he is rather the perfect being which it yearns, so far as it can, to imitate. In the case of things which are not eternal, and are subject (as the heavens, in Aristotle's view, are not) to that kind of change, from a more imperfect to a more perfect form, which we call development, he always seeks the ground of the earliest stages in the result towards which they tend. This is often called his " teleology," or explanation of things by their end or " final cause." The final cause of organic beings is commonly 56 A HISTORY OF PHILOSOPHY sought by him not in their utility to man, but in their own perfection after their kind. Aristotle distinguished four kinds of cause : the material, the formal, the efficient, the final. Thus, fully to explain the origin of a house, we should have to mention the bricks and stones out of which it was built, the form they have been made to assume, the builder who arranged them thus, and the purpose of shelter which as so arranged they are enabled to serve. But on closer inspection all these, except the first, tend to coincide. For the builder is only a cause of the house so far as his mind conceived and his hands carried out the design of it ; and it is only the particular kind of shelter that a house (and not, for example, a tent) affords which such a dis- position of the material is fitted to provide. The efficient and final causes are thus as could be shown even more clearly in the case of a work not of art, but of nature, such as an organism alike aspects of the formal cause. Thus this fourfold scheme does but elabor- ate the more fundamental distinction of two factors in all beings that are not eternal; a matter, which is capable of becoming what when invested with the form it actually becomes, and this form, in virtue of which we call the thing of that kind by the specific (not the individual) name belonging to it. (It is here to be remembered that kind. SUCCESSORS OF PLATO 57 species, form are but different renderings of one and the same Greek word.) What has itself a form or characteristic nature of its own (e. g. marble) may become in its turn the matter or material of something else (e. g. a statue). We can never come face to face with mere matter; apart from some form or other, it would have no character, would be nothing at all. On the other hand, God is pure form without matter, since in his perfect life are no unrealized capacities, to be dis- tinguished as matter from the spiritual activity of knowledge which is his essence. This activity of knowledge, which is the only one in Aristotle's view attributable without absurdity to God, he naturally regarded as the highest possible to man. Accordingly, in his Ethics the godlike life of knowledge is that in which man realizes his noblest capacity, whereby he is distinguished from all other denizens of the earth, and finds therein his greatest happiness. Only because man, in whom an animal nature is conjoined with the pure intellect, cannot lead this life without intermission, does human happiness involve also the exercise of the social and civic virtues. Man is, indeed, by nature a social animal ; he is always found living in some sort of society, if only that of husband, wife, and children. But what Aristotle held to be the highest kind of life was onlv to be found in civilized 58 A HISTORY OF PHILOSOPHY communities of free citizens, such as, to his knowledge, men of Greek race alone had shown themselves capable of forming. What is the best constitution for such a community he sets himself in his Politics to inquire. Although it was with a pupil of his own, Alexander the Great, that there begins for the Greek world a new period, in which the old city-states were reduced to subordinate membership in large empires, Aristotle does not seem to have anticipated the changed course which events were about to take. He still pictured a civilized state as a small independent commonwealth, occupying a single city with its adjacent territory, and not too large to allow of all its citizens taking a personal part in public affairs. Leisure for this purpose was to be secured to the citizens by the institution of domestic slavery, which Aris- totle regarded as based upon the natural incapacity of some men for self-government. Whole nations exhibited this natural incapa- city by setting up, when left to themselves, a despotic ruler, to whom all the rest stood in a servile relation. In the free common- wealth, political equality should correspond to real equality. To any member of the community who (like the " heroes " of Carlyle) should be marked out by an intrinsic supe- riority to all the rest as their natural ruler, SUCCESSORS OF PLATO 59 he others ought to submit. Inequalities of wealth should not be ignored. With Plato's abolition of private property in the ruling class of his ideal state Aristotle was not in sympathy. The end which Plato had in view, the realization of the proverb that " friends have all things in common " would not, Aristotle thought, be attained by such an arrangement. It is true that, in the intimacy of a close friendship, a man may know himself able without question to use what is his friend's as though it were his own ; but this is quite a different matter from the common use by two men of something to one of whom it belongs no more than it does to the other; for such common use neither implies, nor does it always tend to produce, any particular friendship among those who enjoy it. Aristotle does not, then, exclude the possibility of one free citizen being richer than another. Wealth, he holds, gives to its possessors a " stake in the country," which entitles them to a privileged position, sufficient to save them from lying at the mercy of those who have nothing, but not such as to enable them to reduce their poorer fellow-citizens to helpless dependence. Various real inequalities having thus ob- tained due recognition, the general principle of government approved by Aristotle is that equal citizens should rule and be ruled, turn 60 A HISTORY OF PHILOSOPHY and turn about. If Aristotle does not, like Plato, desire to place the control of the State in the hands of philosophers, who are to order the concerns of the public in the light of their knowledge of the supreme principle of order in the universe, this is not because he takes a less exalted view of the functions of philosophy, but rather be- cause he regards human conduct as belong- ing altogether to the world of change and decay, and hence as no concern of the higher philosophy, which deals with the eternal and immutable. Thus, he does not bring into so close a connexion as did Plato the lives of contemplation and of action, the man of science and the man of affairs. This is of a piece with his general tendency to find fault with Plato for laying stress on unity, on what things have in common, to the neglect of equally real and important differences. He regards himself as called to insist especially upon the latter. Each main department of knowledge, he holds, has principles of its own, which it shares .with no other. There are, indeed, prin- ciples which obtain in all departments; of these, the most universally applicable is the " principle of contradiction," which says that nothing can be said at once to be and not to be the same thing at the same time in the same sense. But in no department can SUCCESSORS OF PLATO 61 we gain positive knowledge by the help of these alone without taking into account the peculiar nature of its subject-matter. Thus Aristotle was led to render a great service to the progress of science by delimiting the spheres of its different departments, and mapping out the field of knowledge between them; while, by insisting on the importance as a preliminary to them all of a study of the general conditions under which proof in any department is to be reached, and of such methods of inquiry as can be employed in all, he became the founder of the system of logic which formed for many centuries the basis of philosophical instruction in Europe. His detailed examination of one very common type of reasoning or inference gave it a place in the tradition of the schools as the pattern of all sound reasoning to which it may be questioned whether it was really entitled. This was what is known as the Syllogism ; as an example of which, in the form considered by Aristotle as the most perfect, we may give this : " Beings which