tU- v* ,-. 1 . ^ 'V 6 ^ ^ '%<£- ^ ^ : W vO ©^ <*• ^ ^ / V ,. ''U. ' * * s s ' 4° . % 4, y ,0 Digitized by the Internet Archive in 2011 with funding from The Library of Congress http://www.archive.org/details/courseofphilosopOOIoua A OF PHILOSOPHY. EMBRACING LOGIC, METAPHYSICS AND ETHICS. DESIGNED AS A TEXT-BOOK FOR THE USE OF SCHOOLS.. > by - /: ?^~?~: Rev. A. Louage, C. S. OS ^ - '<- ^ PROFESSOR IN THE UNIVERSITY OF NOTRE DAME. BALTIMOEE: KELLY, PIET & COMPANY. 1873. THE LIBRARY OF CONGRESS WASHINGTOW Entered, according to an Act of Congress, in the year 1873, by KELLY, PIET & COMPANY, In the Office of the Librarian of Congress, at Washington. PREFACE T is the unanimous opinion of those best qualified to judge, that a knowledge of the first principles of Philosophy is necessary to complete any course of classical or scientific studies. Experience as well as reason teaches that those who complete their edu- cation with a course of sound Philosophy, thus acquire an accurate method for the continuation of their studies, for the instruction of others, or for the pursuit of any calling to which they may devote their talents. The man who learns what truth is, learns also to love it ; and will not be easily led astray by the sys- tems of error which are everywhere paraded before him, labelled with the false appellation of Philos- ophy : he despises the contradictions of pseudo- philosophers, he abhors the repulsive doctrines of the wicked, and avoids with care the corruption of morals which always accompanies them. Every- where and always he perceives the presence of the Divinity, and is accordingly filled with awe and reverence : he sees also, with consolation, the excel- lence of his own soul and its future destiny, and not only preserves it from the contamination of vice, but also adorns it with every virtue ;• thus conscientiously discharging all the duties of his station in life, he must ascend higher and higher in the scale of being, 4 PREFACE. When we thus point out the abundant and inesti- mable fruits of Philosophy, it is evident that we do not speak of that so-called Philosophy which ignores the light of Divine revelation, but of that true Christian Philosophy which is guided as far as pos- sible by reason, but which freely admits the light of faith where that of reason fails : for, as we shall see, reason alone is not capable of completely solving some of the most serious problems which concern the salvation of man. The young man who, while at college, has either wholly neglected to study the rules of judging and knowing, or who has not engraven them deeply on his mind, wanders without a guide through dark and devious ways, and is " carried about by every wind of doctrine. ' ' He reads indiscriminately every book, good or bad, that chance throws in his way, and peruses them with little attention or reflection. Hence he fills his mind with imperfect notions of things, without any order ; everywhere he sees con- tradictory systems, and in the midst of this general darkness he remains uncertain of the truth, and even becomes doubtful of the very existence of cer- titude. Soon the truth of religion appears to him as not sufficiently proved ; and, owing to the preju- dices to which he has yielded, he begins to deny that there is any excellence in virtue or any turpitude in vice. Passions rise in his heart, which, not being restrained, but rather flattered and excited by many causes, soon lead to deplorable results ; for they shake his reason, which is already weak and deprived of its natural support, they destroy the vigor of his PREFACE. O physical system, they deprave his nature, and finally carry the unfortunate youth to utter destruction. That this is not an overdrawn picture is plain to any one who chooses to look around him with an unprejudiced eye; and it shows conclusively the importance of a knowledge of the primary principles of Philosophy. On this knowledge, in truth, de- pends the progress which we shall make in science, the solidity of our mind ; our love of truth and detestation of falsehood, our sagacity in choosing what is best, the integrity of our morals, the peace of families, the well-being of society, in a word, our happiness both in public and in private life. The teacher, therefore, who is incompetent, neg- ligent or dishonest, is the cause of an irreparable loss to those under his care ; while he who is learned, diligent and consistent in his instruction, sows in the minds of those committed to his charge the seeds of truth and virtue which will bring forth an abun- dant harvest of the richest fruits of a good education. To attain so desirable an end, the pupil should be guided, not by obscure and uncertain precepts, but by those which are established upon the clearest principles of reason : even as a child as yet unac- quainted with the way is guided, not by the hand of an ignorant or a dangerous man, but by that of his father. We do not approve of the method of teaching Philosophy by lecture ; for long lectures, however well developed, are not always understood by the student and are very easily forgotten : we are rather in favor of placing in the hands of the pupil a b PREFACE. small but comprehensive text-book, which, he can readily commit to memory, and easily retain. Such a text-book should be concise without being obscure, so that the attention of the student may be sufficiently attracted and exercised ; but, more than all, a book written for this object should be exact. An elementary book of this kind is not often found ; indeed it may be doubted whether one pos- sessing all the qualities mentioned above exists in any modern tongue. Some excellent compendiums written in the Latin language have been published since 1825 ; but they cannot serve our purpose, which requires a manual of Philosophy adapted par- ticularly to the wants of those who are not acquainted with the classics. To unlock the treasures of Phi- losophy for them, we concluded that it would be well to prepare a text-book having as far as possible the requisites mentioned above. During the preparation of our manual we have diligently consulted the best works on the subject ; and we now submit the result of our labors in the form of an elementary text-book on Philosophy, which we trust will meet the requirements of those for whom it is intended : and may God grant that, owing to the good intentions of the author, this book may be the means of advancing the best interests of the youths for whom it was written. S. K D. B. INTRODUCTORY. BEFOBE entering the sanctuary of Philosophy, a few words are necessary by way of introduc- tion. We shall arrange these preliminary remarks under four heads. Under the first we shall give the Definitions of several woeds of common occurrence : under the second we shall examine the Definitions of Philosophy: under the third we shall give the Divisions of Philosophy : and under the fourth we shall say something of Argument. I. Definitions of Words. A being or thing is that which exists or may exist : it is therefore twofold, real or possible. Existence is the real union of the parts or attri- butes which constitute a being. Possibility is the agreement of the attributes which constitute a being, in such a way that its existence does not involve any contradiction. The attributes are the qualities of a being : they are essential or constitutive when the thing cannot exist without them, and accidental when the thing can exist without them. The essence of a being; consists of the collection of O INTRODUCTORY. its essential or necessary attributes. The essence of a thing is also called its nature ; although the word nature is more extensive than essence, since the nature of a being sometimes includes its accidental as well as its essential attributes. Nature is also used to signify the whole collection of corporeal beings. A genus is a collection of beings having one or more attributes common to each. A genus must be sufficiently general to be divided into subordinate classes, called species. A species, therefore, is a collection of beings be- longing to one and the same genus, but having par- ticular and constitutive properties by which they are distinguished from any other collection of beings of the same genus. For example, being, the most general genus, is divided into two species, corporeal and incorporeal beings. These two species are each divided into other species, and consequently they are genera with reference to the subsequent divisions. Corpo- real bodies form two species, things with life and things without life. Things with life, considered -with reference to a further division, form a genus which is divided into two species, animals and vege- tables. The genus may be either remote or proximate. It is remote when there is at least one division inter- vening between the species and the genus referred to. For instance, when I say, Man is a rational being, the genus, being, is remote ; but it is proxi- iinate when I say, Man is a rational animal. INTRODUCTORY. 9 Each species must have an essential attribute which makes it distinct from every other species of the same genus : this attribute is called the difference. When this difference consists of an attribute which separates every being of the species from every being of another species, it is called the specific difference. We have an example of this difference in the follow- ing definition, Man is a rational animal, where the word rational indicates the specific difference, dis- tinguishing man from any other species of the genus animal. Individuals are those beings to which, considered separately, the same genus and the same difference pertain. In Ontology we shall give the definitions of Sub- stance, Modification, Subject and Object, also of Order and Relation. Science is a series of notions deduced from princi- ples firmly established, disposed in a methodical order and referring to one and the same object. Science is either subjective or objective; subjective when we consider it as existing in our own minds, and objective when we consider it as existing in the object contemplated : it is again either speculative or practical. Practical science is the source of art . Art is the application of science to external things, according to determined rules. We will here ob- serve that the same species of knowledge may be at. the same time a science and an art. Arithmetic and Geometry, considered in themselves, are sciences ; but applied to external things they are arts. Logic, 1* 10 INTRODUCTORY. considered in itself, is a science ; but applied to trie investigation of truth and its manifestation, accord- ing to determined rules, as in the method of Aris- totle, it is the Art of Eeasoning, or the Art of Thinking. Knowledge, in general, is the representation taking place in the mind, of something, in some manner ; it differs very little from idea, as we shall see. It is intuitive when the object appears so clearly to our intellect that we perceive it without reasoning, and discursive when we need some de- monstration to perceive the object. Knowledge has for its objects either natural or supernatural things. Faith, in general, is the assent of the mind to some truth, on the testimony of another person. When this assent is founded upon the authority of G-od, it is Divine Faith ; it is Human Faith when established upon the testimony of men. II. Definitions of Philosophy. It often becomes necessary to give definitions, in order to avoid obscurity or uncertainty. A defini- tion is an explanation of a word or of a tiling. The definition of a word is said to be etymological when its origin is given, and significative when its mean- ing is explained. The definition of a thing is that which shows the nature of the thing. It may be merely descriptive, and then the definition is called imperfect; or it INTRODUCTORY. 11 may be accurate and perfect, and this only deserves the name of definition. Description is suitable to oratory, but definition belongs especially to Philos- ophy : it gives precisely what is necessary in order that the thing may be understood and distinguished from every other thing, by enumerating its essential qualities. Three conditions are requisite to a perfect defini- tion : 1st, It must be clear, that is, free from any obscure or ambiguous expression ; 2nd, It must be orief, that is, free from all unnecessary words ; and 3d, It must give the 'proximate genus and the specific difference. When these three conditions are found, the definition applies to the thing defined, and to nothing else, so that the thing and its definition are reciprocals. Philosophy has been defined as "the science of things knowable by the light of reason," or "the science of reason." But these definitions, while they distinguish Phi- losophy from theology, do not separate it from the physical and mathematical sciences ; and in our day these sciences have been so far extended that they have ceased to belong to Philosophy, as it is now taught in the schools. The following definition of Philosophy might consequently be accepted : ' ' The science of supersensible things knowable by the light of reason." This definition has the three requisite marks : it is clear, short, and contains the proximate genus, "science," and the specific difference, "super- sensible," which word distinguishes Philosophy from the physical sciences, and "knowable by the 12 INTRODUCTORY. light of reason," which words distinguish Philos- ophy from theology. III. Divisions of Philosophy. Division, in general, is the distribution of a whole into its parts. A whole is that which is formed of parts really or logically distinct. The whole is said to be metaphysical, jjhysical or logical, according as its parts belong to one or other of these orders. The division, to be accurate, must have these three conditions : 1st, It must be adequate, that is, it must include as many members as there are in the whole which is to be divided ; 2nd, It must be distinct, that is, one part must not be included in an- other ; 3d, The parts must be proximate, otherwise there would be confusion, the following division, for instance, would be wrong : Living beings are divided into three classes, men, beasts and plants. A prox- imate division would be : Living beings are divided into two classes, animals and vegetables, and so continue, always giving first the proximate, or nearest, division, and the subdivisions in like order. Philosophy, as we have learned, is the science of supersensible things. In order to proceed method- ically in the acquisition of this science, we must first give the rules for the investigation of truth, and then investigate the things which form the object of this science, beginning with the most important, namely, God and the soul. The nature of God and the soul being known, we may examine the relations existing between God and the soul, between the soul INTRODUCTORY. 13 and the body, and finally the relations of men to each other considered as social beings. We have then three parts which form the Divisions of Phi- losophy: namely, Logic, Metaphysics, and Ethics. IV. Argument. The different points to be treated under this head will be given in Logic. We will here say only a few words in regard to equivocal propositions, which we may sometimes' have to deal with. 1st. We must distinguish and point out clearly the equivocal expressions. 2nd. If these expressions are not clear of them- selves, we must define and explain them. 3d. We must concede the proposition in the sense in which it is true, and deny it in the sense in which it is false ; and in both cases give our reasons for doing so, if necessary. A COURSE OF PHILOSOPHY. PART I.— LOGIC. LOGIC. Definition — Division. FOR the acquisition of science the human mind must first be provided with rules, and so be enabled to avoid error and establish truth on the solid foundation of reason. The word philosophy, as we have seen, is as uni- versal as the word science itself, and logic is the key of this science. Logic is consequently the first part of Philosophy, the part which treats of the first efforts of the human mind to discover truth, and afterwards gives rules by which this truth may be demonstrated. We may therefore define Logic to be, "The science which directs the operations of our mind in the investigation and demonstration of truth/' When this science is put in practice it becomes "The Art of Reasoning," which words may be ac- cepted as a definition of logic, considered as an art. In the foregoing definitions we find the three re- quisite conditions of a good definition : 1st, clearness, 2nd, conciseness, and 3d, reciprocity, that is, the proximate genus and the specific difference are given. 18 LOGIC. The natural order observed by the mind in the investigation of truth may be described as follows : We first represent objects*to ourselves, we next judge of them, we then compare our judgments and draw conclusions, and, finally, we arrange these conclu- sions in a certain order. Hence we have in the science of logic four different .parts or divisions ; the first treating of our Ideas of objects, the second of our Judgments concerning those ideas, the third of our Eeasoning concerning the judgments, and the fourth of the Method in which we dispose of the con- clusions of our reasoning. As soon as we have considered these four divisions of the science we shall apply it to a the investigation of the existence of truth, or Certitude ; and, logically speaking, this question comes first. Is there any- thing certain, is there any certitude? and, if so, how can Ave prove its existence ? Although this question, in reality, forms the introduction to the study of Philosophy, since without an affirmative answer to it we cannot make one step in the science, yet some authors treat it as a part of logic ; and we adopt this plan as more convenient, and shall therefore treat of certitude as the fifth part of logic. FIRST DISSERTATION. ON IDEAS. An idea may be considered as existing either in the mind or out of it : consequently this first disser- tation may be divided into two chapters. LOGIC. 19 CHAPTEK FIKST. Of Ideas Considered as Existing in the Mind. " An idea is the mere representation in the mind of some object." We cannot, therefore, have an idea of nothing ; for nothing has no property or attri- bute by which it might be represented in the mind. The definition- of an idea being given, we have now to examine, 1st, the division of ideas, 2nd, their properties, and 3d, the operations of our mind in regard to them. §1. The Division oe Ideas. r In regard to their origin, some authors divide ideas into three classes : First, innate ideas, or those born 'with us ; second, adventitious ideas, or those coming to us from various causes in the course of time ; and third, factitious ideas, or those formed by ourselves. In regard to their object, we have, first, the idea of substance, when we consider the substance of a thing as abstracted from its modifications ; second, the idea of modification, when we consider the mod- ifications of a thing as abstracted from its substance (these two ideas are called abstract ideas) ; and, third, the idea of modified substance, which is called a concrete idea. Concrete ideas may be produced by sensation or by the imagination. They are produced by sensa- tion when they represent objects which strike our senses and which, therefore, really exist : they are produced by the imagination when they represent 20 LOGIC. objects which, may exist, hut which do not strike our senses. All these ideas are called ideas of sensible things when their objects are sensible things ; and they are called ideas of intellectual things when the objects which they represent cannot affect the senses : the ideas of moral things belong to this second class. An idea is simple when the object represented can- not be divided, as, "an affirmation ;" complex when the object is qualified, as, " a good man ;" compound when the object may be divided into several parts, as, "a horse," " a tree ;" collective, when the object is a unity formed of several objects belonging to the same species, as, "an army;" universal when the object represents all the beings of the same species, as, " man in general;" particular when the object represents only a part of the beings belonging to the same species, as, "several men;" singular when the object refers to one individual of a collection, as, "Peter," "John;" and adequate when the object appears with all its attributes : God only has ade- quate ideas, we have but inadequate ones. §11. Properties of Ideas. Ideas are, first, either true or false. They are true when they conform with their objects, false when they do not. But since this conformity is always with the objects as represented in our minds, and not as they may be in reality, we may, with this explanation, admit the opinion of those who pretend that there are no false ideas. Ideas are, in the second place, either clear or obscure, and these LOGIC. 21 words need no explanation. Thirdly, they are either distinct or confused. An idea is distinct when it can be readily separated from any other idea, as the idea of "a certain house" or of "a certain per- son;" and it is confused when the object cannot be distinctly determined. If I say, " Many persons are standing at a distance from me, and I cannot see whether they are armed or not, ' ' I have a confused idea. . ' The comprehension of an idea signifies the sum of the attributes which constitute the nature of the object. The comprehension of the idea of man in- cludes everything necessary to constitute a man, as man, thus distinguishing him from everything else, as a tree or a stone. The extension of an idea signifies the whole collec- tion of the individuals which the same idea embraces. The extension of the idea of man includes all those beings that have the human nature, that is, all men. § III. Opeeations of the Mind in Begaed to Ideas. The principal operations of the mind in reference to ideas are attention, abstraction and comparison. Attention is that operation of the mind by which we lay our ideas, as it were, before the eyes of the mind, in order to examine them with care and master them. Attention and reflection constitute the foundation of science and the source of learn- ing. Abstraction is that operation of the mind by which we consider one or more qualities of an object, the other qualities being laid aside. Abstraction is not 22 LOGIC. only possible and even easy of attainment, out it is also necessary. Having examined several qualities and found that they belong to a certain object, if we unite these qualities in order to form this object again, we per- form an operation which is called synthesis : on the contrary, if an object is given us to study, and we divide it into its parts, examining successively each part, we perform an operation which is called analy- sis. We may, therefore, see that analysis is a de- composition, while synthesis is a recomposition. When, in order to form a species, we collect several individuals having Common properties, we perform an operation which is called generalization. When we consider two or more ideas, in order to find their consistency or their inconsistency, we per- form an operation which is called comparison. This operation is, of course, the most important ; without it we could not improve in any branch of science or art. CHAPTER SECOND. Of Ideas Considered as Existing Out or the Mind. There are three ways by which we may express what we represent to our mind, namely, gestures, speech and writing ; and these three are designated by the general appellation of signs. For the development of this chapter see the re- marks on the "Origin of Language," in experi- mental Psychology. LOGIC. 23 SECOND DISSERTATION. ON JUDGMENT. When the mind after having compared two ideas declares their consistency or their inconsistency, it makes a judgment. Consequently c ' Judgment is that operation of the mind hy which it pronounces on the consistency or the inconsistency of two ideas, or declaring that a certain quality exists or does not exist in a certain object. We may readily under- stand that our errors proceed from mistaken judg- ments only, for we cannot err in perceiving or in feeling. Here again we may consider judgment as existing either in the mind or out of it, and consequently this dissertation is also divided into two chapters. CHAPTEK FIKST.~ Of Judgment Considered as Existing in the Mind. Judgment is a positive act of the mind, and not a mere sensation, as Condillac said, or a perception, according to the opinion of Mallebranche. It is an act, since we judge and pronounce, and we can do neither without acting ; it is, besides, a simple act, since it consists of an affirmation or a negation, and, consequently, cannot be divided. Judgment is very probably produced both by the intellect and by the will. A judgment is either necessary or free. A neces- sary judgment is one formed when the mind is so strongly impelled to judge that it cannot refrain from judging. ' ' I exist, " is a necessary judgment. 24 LOGIC. A free judgment is one which the mind is not forced to pronounce. A judgment is, in the second place, either true or false, depending on the fact as to whether the things are, or are not, as the mind declares them to he. Thirdly, a judgment is certain when it is estab- lished on an infallible foundation, as, "Our Lord died," "Bodies exist/' Fourthly, a judgment is evident when it rests upon a clear and distinct perception of the consistency or the inconsistency of two ideas, as, "Two and two equal four." Lastly, a probable judgment is one established on trustworthy, but not infallible, reasons, as, " It is probable that a sick man will recover when several good physicians are of opinion that such will be the "case." CHAPTEE SECOND. Of Judgment Considered as Existing out of the Mind. "When we express our judgment we form what is called a proposition. To constitute a proposition three terms are necessary, a subject, a verb, and an attribute, one or even two of which may be under- stood. In every proposition the attribute always expresses a notion more extensive than the subject. Aristotle gives ten classifications of attributes, which he calls cle categoriis ; Kant gives but four. Nothing is more obscure and less useful than such classifica- tions. A proposition is universal when the subject is taken LOGIC. 25 in all its extension, as, " Every substance is divisi- ble/' "No spirit is mortal." A proposition is particular when the subject is not taken in its full extension, as, "Some men are learned." Even such expressions as "All young men are fickle" are but particular propositions. A proposition is singular when the subject is but one individual, as, " Cassar was a great general." A proposition is affirmative when the attribute is declared to be consistent with the subject, negative when declared inconsistent. The following axioms in reference to affirmative and negative propositions are given in this connec- tion ; we shall need them farther on : 1st Axiom. The attribute of an affirmative propo- sition is taken in its entire comprehension, but not in its entire extension ; consequently, the attribute of an affirmative proposition is a particular term. For example, if I say "All angels are spirits," the attribute ' ' spirits ' ' is taken in its entire compre- hension, but not in its entire extension ; for other beings than angels may be spirits. 2d Axiom. The attribute of a negative proposition is not taken in its entire comprehension, but is taken in its entire extension ; consequently, the attribute of a negative proposition is a universal term. For example, if I say, "A man is not a stone," the at- tribute ' ' stone ' ' is not taken in its entire compre- hension, since both "man" and "stone" have the comprehension of material substance ; but it is taken in its whole extension, for no stone whatever is a man. A proposition is grammatical when we consider 2 26 LOGIC. only the terms as abstracted from the sense, and logical when we consider the proposition as having a determined sense. The sense of a logical proposition may be proper or foreign: it is proper, or natural, when we give to the words their ordinary meaning ; and it is foreign when we give to the terms a signification which is not their own. The sense may also be either divided or composite ; or, to use the Latin expressions, the proposition may be taken either in sensu diviso or in sensu composite. For instance, if I say, "The blind may see," the proposition is true in sensu diviso, but false in sensu composito. In the first sense the proposition means, "The blind, if restored to sight, may see ;" in the second it means, "The blind, though remaining blind, may see." In the course of this work we shall have more to say of this distinction. A proposition is true when it declares its subject to be as it is in reality, as, " God is powerful ;" and false when it declares its subject to be as it is not in reality, as, " God is cruel." Sometimes a proposition has two senses, and then it is called equivocal. To obtain the true sense of a proposition it is often necessary to stake the propo- sition in a different manner, to change the order in which the terms have been first presented ; some- times also when two propositions are given and compared it becomes necessary to judge of the con- trary or the contradictory of one of them: it is therefore necessary for us to learn something of the conversion and the opposition of propositions. LOGIC. 27 §1. Conversion of Propositions. The conversion of a proposition is the changing of it into another proposition of the same -meaning. This conversion is simple when the whole attribute is substituted for the subject, and the subject for the attribute ; and it is accidental when a part only of the attribute takes the place of the subject. The following rules must be observed in the con- version of propositions : Kule I. The quality and the quantity of the prop- osition must be retained in the conversion. Rule II. A universal negative proposition and a particular affirmative proposition may both be conr- verted by simple conversion : for, in the first, both terms are universal (2d Axiom), and in the second, both are particular (1st Axiom); consequently, the quality and the quantity are kept in the conversion. Examples of simple conversion : No man is a stone ; no stone is a man, Some men are good persons ; some good persons are men. Rule III. A universal affirmative proposition cannot be converted by simple conversion, for its attribute is a particular term (1st Axiom) ; except in necessary and reciprocal statements, that is, when they are identical in regard to the sense, as is the case in definitions. For example, " All priests are men" is not equivalent to "All men are priests" but to "Some men are priests." But "All circles are round" is equivalent to its reciprocal, "All round figures are circles." Rule IV. A particular negative proposition cannot 28 LOGIC. be converted either simply or accidentally ; for such a conversion would violate the first rule, by chang- ing the quality or the quantity of one of the terms. §11. Opposition of Propositions. When I say "Peter is a learned man," and " Pe- ter is not a learned man," I have two propositions which are opposite. Opposition is, therefore, the negation in one prop- osition, and the affirmation in another, of the same attribute, concerning the same subject and with the same reference. Consequently, in these two propo- sitions, " Peter is good" and "Paul is not good," there is no opposition ; nor is there .any opposition in the following, "Peter is learned in philosophy" and "Peter is not learned in theology." To con- clude, two propositions are in opposition when one of them denies what the other affirms. It follows that two negative propositions cannot be in opposition. Two propositions are said to be contrary when in one of them more is said than is necessary to refute the other. Example : "All men are just. No man is just." Two propositions are called contradictory when in one is said precisely what is necessary to refute the other ; as, " All men are just. A certain man is not just." Evidently, two contradictory propositions cannot both be either true or false ; for, if so, the same thing wQiild be and not be at the same time ; that is, the same attribute would be consistent and not consistent with the subject, which is absurd. logic. 29 As a corollary, since two contradictory proposi- tions cannot be true and false at the same time, it follows that when one is true the other is false, and vice versa. Two contrary propositions cannot both be true at the same time, but both may be false : for, as two contradictory propositions cannot both be true at the same time, since in one of them is said precisely what is sufficient for the refutation of the other ; so, a fortiori, two contrary propositions cannot both be true at the same time, since in one of those proposi- tions more is said than is needed for the refutation of the other : also, since, in one of the two contrary propositions more is said than is necessary to refute the other, there may be a middle term which is the true one ; and consequently the two contrary propo- sitions may both be false. Examples: " All men are just. No man is just," — both false. The middle term, "some men," is the true subject ; and "some men are just " is the true proposition. THIRD DISSERTATION. ON EE ASOJSTING . When after comparing several judgments we draw a conclusion from them we are said to reason. Rea- soning is, therefore, an act of the mind deducing a judgment from other judgments ; and when expressed in words it forms an Argument. Argument then is to reasoning what the proposition is to judgment, namely, its formal expression in words. 30 LOGIC. Seasoning is said to be immediate when no com- parison is needed, and mediate when a comparison is necessary. Reasoning affects only formal truth ; hence, if we assume a false principle we shall, by good reasoning, deduce a false conclusion. There are many sorts of argument, of which the syllogism is the most common. We shall divide this dissertation into five chap- ters. In the first we shall treat of the syllogism and its rules ; in the second, of the different kinds of syllogisms ; in the third, of the forms of argument other than the syllogism ; in the fourth, of sophisms ; and in the fifth, of the sources of sophisms. CHAPTER FIRST. Of the Syllogism and its Rules. The syllogism is an argument consisting of three propositions so arranged that from the first two, called the premises, the third necessarily follows as a conclusion. In every syllogism there are three terms, the major, or greater, the minor, or less, and the middle. The major term is the attribute of the conclusion, of which the minor is the subject : as we have already learned, the attribute is always a greater term than the subject. The middle term, which is the term of comparison, is not found in the conclusion. The first proposition of the syllogism is called the major proposition, because it contains the major term ; the second is called the minor, because it con- LOGIC. 31 tains the minor term ; and the third, which, as we have just seen, contains both the major and the minor term, is called the conclusion. The major and the minor are together called the premises, or the antecedent; and the conclusion is also called the consequent. Example : Middle Term. Major Term. "*| Major. All bad men are miserable ; Premises, or Minor Term. Middle Term. ( Antecedents. Minor. All tyrants are bad men ; J Conclusion. All tyrants are miserable. Conse- quent. The minor premise may precede the major. Eules of the Syllogism : 1st. The syllogism must have but three terms. 2d. No term must be greater in the conclusion than it is in the premises. 3d. The middle term must be at least once a gen- eral term. 4th. No conclusion can be deduced from two pre- mises which are either negative or particular. 5th. Two affirmative propositions cannot produce a negative conclusion. 6th. The conclusion follows the weaker premise. That is, when one of the premises is a negative prop- osition the conclusion will be negative, and when one of the premises is a particular proposition the conclusion will be particular. Examples of faulty syllogisms : Against Rule 1st. Every man is a spirit; 32 LOGIC. Every substance is divisible. — -Four terms, no con- clusion. Against Rule 2d. Every animal is a living being ; Every animal is a substance ; Every substance is a living being. Every substance, in the conclusion, is a general term, and it is a particular one in the minor. Against Rule 3d. Every man is an animal ; Every brute is an animal; Every man is a brute. The middle term is taken twice in a particular sense and with a different reference, which consti- tutes two different terms, consequently, there are four terms in the premises. Against Rule 4th. No man is a stone ; Man is not marble. — No conclusion. Against Rule 6th. The Italians are soft ; The Italians are men ; Hence (some) men are soft. This syllogism is good, but the following would be wrong : No man is a stone. Marble is stone. Marble is man. Syllogisms may be divided into four classes accord- ing to the position of the middle term. LOGIC. 33 In the first class — The middle term is the subject of the major and the attribute of the minor. In the second class — -The middle term is the attri- bute of both premises. In the third class — The middle term is the subject of both premises. In the fourth class — The middle term is the at- tribute of the major and the subject of the minor. In the first two classes we may have four cases, or forms of syllogism ; in the third class we may have six forms ; and in the fourth, five forms. Each of these cases, or forms, is designated by a word con- taining three vowels. The first two vowels indicate the quantity of the premises, and the third indicates the quantity of the consequent. There are, as we have seen, four kinds of proposi- tions, which are indicated as follows : 1st. Universal affirmative — by the vowel a. 2d. Particular affirmative — by the vowel i. 3d. Universal negative — by the vowel e. 4th. Particular negative — by the vowel o. We will illustrate the use of these vowels by two examples : Middle First. All virtuous men are happy Middle. I f ^Uq All good men are virtuous ; One form of the first class. All good men are happy. Second. Middle. ^ C)r\Q No vicious conduct is praiseworthy; ? ' term Middle. ^ of the All truly heroic conduct is praiseworthy ; ( '-, J '■ | second No truly heroic conduct is vicious. J class. 2* d4 LOGIC. In the first example, "both of the premises and the conclusion are universal affirmative propositions, and, "by the notation given above, must each be indi- cated by the vowel a. Hence the word used to desig- nate this example must contain the vowel a three times. Barbara is the word used for this purpose. In the second example, the major premise is uni- versal negative, and therefore indicated by e; the minor is universal affirmative, and hence indicated by a; while the conclusion, universal negative, is designed by e: the word celarent, therefore, desig- nates the form represented by this example. It will now be enough, without further explana- tion, to give the words used to designate each form in the four classes of svllo2;isms : 1st Class. 2d Class. 3d Class. 4th Class. Barbara, Celarent, Darapti, Bramantip, Cesare, Camestres, Disamis, Camenes, Darii, Festino, Datisi, Dimaris, Ferio. Fakoro. Felapton, Fesapo, Dokamo, Fresison. Feriso. CHAPTER SECOND. Of the Different Sorts of Syllogisms. The syllogism may be simple, complex, or com- pound. The simple syllogism is that of which we have treated in the preceding chapter. A complex syllogism is one whose conclusion contains complex terms ; it may always be reduced to a simple syllo- gism. LOGIC. 35 Example : f Divine law obliges us to honor the pas- p i J tors of the Church ; 1 '" | Benedict is a pastor of the Church ; [_ Hence, divine law obliges us to honor him. This syllogism is equivalent to the following : f Our pastors ought to be honored ; Simple. A Benedict is our pastor ; [Hence, he ought to be honored. The syllogism is compound when the major is a conditional, disjunctive, or negative conjunctive proposition. I. The major is conditional when it consists of two parts, the one called the antecedent and the other the consequent, united by if. In this case, when we concede the antecedent in the minor we must affirm the consequent in the conclusion, and when we deny the consequent in the minor we must also deny the antecedent in the conclusion — verum prius, ergo et poster ius ; falsum consequens, ergo et antecedens — that is, the first being true, the second is true ; and the second being false, the first is also false. Example : If Peter is wise he will stay away from gambling houses ; 1st. But Peter is wise ; hence, he will stay away, &c. 2d. But Peter will not stay away, &c; hence, Peter is not, &c. II. The major is disjunctive when it consists of two or more parts incompatible with one. another, and united by either — or. In this case, when one LOGIC part is affirmed in the minor the other is denied in the conclusion. The parts forming the major must be contradictory propositions. Example : We must either restrain our passions or yield to them ; But we must restrain them (since reason and re- ligion teach us to do so) : Hence, we must not yield to them. Since the two propositions forming the major ought to he contradictories, there should he no mid- dle term between them. Example : We must either obey governments commanding evil to be done, or we must revolt against them : But we must not obey governments commanding evil. &c: Hence, we must revolt against them. Here, the major term, which should consist of two contradictories, is made up of two contraries, both of which, as we have seen, may be false : hence the error in this example. The truth is contained in a middle proposition. "We must suffer persecution.'"' III. The major is negative conjunctive when it consists of two contrary propositions. In this case, when we affirm in the minor we must deny in the conclusion, for both propositions cannot be true ; but if we deny in the minor we cannot absolutely affirm in the conclusion, for two contrary proposi- tions may both be false. The rule is. therefore, s follows : One part ought to be affirmed in the minor and the other denied in the conclusion. LOGIC. 61 Example : No one can serve God and mammon ; The avaricious man serves mammon ; Hence, lie does not serve God. CHAPTER THIRD. Of the Forms of Argument other than the Syllogism. 1st. The EntJiymeme. — This is an abbreviated syllogism, in which one of the premises is omitted. Example : God is good ; Henee he should be loved. The major, " We should love those who are good," is omitted. 2d. The Epichireme.- — This is a syllogism whose major and minor are accompanied with proofs. The substance of Cicero's beautiful " Oration tor Milo" is given in the following Epichireme : It is lawful to kill those who lie in wait to kill us (this is proved by the natural law and by the laws of nations — many examples) ; But Clodius lay in wait to kill Milo (this is proved fey the number of armed men who accompanied Clodius, his absence from Rome .at the time of the attack, &c); Hence, it was lawful for Milo to kill Clodius. An Epichireme may be reduced to a single syllo- gism. 3d. The Sorites.- — This is an accumulation of prop- ositions, so connected that, the attribute of each is 38 LOGIC. made the subject of that which follows, and the sub- ject of the first becomes the attribute of the last. The propositions must be well " chained/'" so that there may be no middle term between the attribute of one proposition and the subject of the following ; and no equivocal proposition should be employed. Example : Avaricious men desire manv things, Those who desire many things are in need of many things, Those who are in need of many things are dissat- isfied with their condition, Those who are dissatisfied with their condition are not happy ; Hence, avaricious men are not happy. 4th. The Dilemma.- — This is an argument in which we conclude of the whole major, which is generally a disjunctive proposition, what we have concluded of each j>art. It is called a horned argu- ment, because it strikes on both sides. Example : When the wicked die, either they are utterly destroyed or their souls are immortal : If they are utterly destroyed there is no hope of eternal happiness for them ; If their souls are immortal there is also no hope of eternal happiness for them, since God is just ; Hence, there is no hope of happiness for the wicked after death. To have the dilemma good no middle term must be possible in the major, and the conclusion must be true after each part. LOGIC. * 39 5th. Induction or Enumeration.- — This is an argu- ment in which the major is an enumeration of partic- ulars, from which a universal conclusion is deduced. That the argument may be absolutely conclusive, the enumeration must be complete. 6th. The Example. — This is a common form of argument in which a single conclusion is drawn from a single proposition. This may be done in three ways : by' similitude, or comparison {a pari), by opposition, or contrast (e contrario), and by su- periority (a fortiori) . Examples : 1st. apari. God forgave David when he repented ; a pari, He will forgive me. . 2d. e contrario. Intemperance is hurtful to health ; e contrario, Temperance is favorable to health. • 3d. a fortiori. John's conversation for even one hour is tedious ; a fortiori, it would be tedious for a whole day. CHAPTER FOURTH. Of Sophisms. The word sophism comes from the G-reek sophizo, which signifies to teach ivisdom; and the Greek noun sophismos means wise invention. From this etymol- ogy it is easy to understand that the word sophism had not in the beginning the meaning which it has at present. Men of subtle intellects, falsely called philosophers, have abused their powers of reasoning so far as to construct a theory for reasoning falsely, a theory by which fallacies are logically established 40 LOGIC. as if they were truths. This is what is now called sophistry. A sophism, then, is a false reasoning, with the intention of deceiving. "When the sophism results from ignorance in the reasoner, it is called a paralogism. Aristotle divides sophisms into three classes : 1st. formal sophisms ; 2d. material sophisms, or sophisms extra dictionem ; and 3d. verbal sophisms, in dictione, that is, sophisms existing in the words used. Formal sophisms are syllogisms badly constructed. Of these we have already spoken. Material sophisms are the following : (a) Ignoraiitia elenchi, which may be translated, "ignorance of the subject." This occurs when we prove what is not in question, or what is not denied by our opponents ; also when we suppose them to be actuated by principles which they disavow, or when we draw from their words or actions inferences which they would not admit. This sophism is of common occurrence ; it comes from precipitation, prejudice, and feelings of pride or hatred towards our oppo- nents, but still more from equivocation in terms not well defined. In order to avoid this last source of error, we must know both the precise sense and the exact extent of the expressions used by our oppo- nents. (b) Petitio principii, or "begging the question." * This species of false reasoning takes place when we suppose as proved that which is to be proved. There is no substantial difference between this sophism and that called the vicious circle (circulus vitiosus), or arguing in a circle, which consists in proving two LOGIC. 41 propositions by one another, neither of them being otherwise proved. Examples : The earth is immovable, because the sun moves around it. Evidence is infallible, because God is infinitely true ; and God is infinitely true, because it is evi- dent, &c. (c) Non causa pro causa, or "Not the cause for the cause." This sophism occurs whenever we give as the cause of some effect that which is not its cause. This happens frequently, especially in the case of "Post hoc, ergo propter hoc," — after this, therefore on account of this. (d) Imperfect enumeration . No explanation needs to be given of this kind of false argument. (e) Fallacy of objection. This sophism results when we consider as a cause, or as an essential, that which is only an accident. The following are examples of the fallacy of ob- jection : (1) Philosophy rendered many men impious ; then philosophy is a bad thing. (2) False miracles have been believed; then no faith ought to be given to miracles, &c. Verbal sophisms, or sophisms in dictione, are the following : (a) Fallacy of division and composition. Passing from a distributive to a collective sense in the use of words. Example : Two and one are . even and odd ; 42 LOGIC. But two and one are three ; Therefore three is even and odd. One and two are even and odd when divided (in sensu diviso), but not when united (in sensu compos- ite)). This distinction is the only one to he given in such cases. We may see that in the above sophism there are four terms : two and one are taken in sensu diviso, or distributively, in the major ; and in sensu composite, or collectively, in the minor. Hence the syllogism involves an error against the 1st rule. 2d. Passing from a collective to a distributive sense ; or attributing to several parts of a collection what is true only of the collection itself. Example : The Apostles were twelve ; Peter and James were Apostles ; Therefore Peter and James were twelve. Here again we have four terms in the premises. The Apostles are taken together (in sensu composite) in the major ; and separately (in sensu diviso) in the minor, — and no conclusion can be drawn. (b) Fallacy of accident. This consists in assert- ing something of a subject in a general sense, in one of the premises ; while in the other premise we con- nect with that subject some accidental peculiarity. Example : You now have the same feet that you always had ; But you once had small feet ; Therefore you now have small feet. Putting this sophism in the form of a regular syl- logism, we shall perceive that there are four terms in the premises. L G I c . 43 Your present feet are those of your childhood ; The feet of your childhood were small feet ; Therefore your present feet are small feet. In the major, the u feet of childhood" means the essence of those feet, while in the minor it means their form or shape. Hence the middle term being taken in two different senses we have four terms in the premises and can draw no conclusion. Besides these two kinds of verbal sophisms, we have (c) that of Equivocation, (d) that of Amphib- ology, and (e) that of Figure. Example of a sophism of figure : No creature laughs but man ; But a meadow laughs ; Hence a meadow is a man. We may observe that ' ' meadow ' ' is first taken in a figurative sense and then in a literal. Doctor Ubaghs, speaking of these last three so- phisms (c, d, and e), says that they do not deserve to be mentioned, since they could embarrass no one but a child or a person of very dull mind. CHAPTEK FIFTH. Of the Sources of Sophisms. The sources of sophisms are : 1st. Precipitation. We are liable to commit a sophism whenever we pronounce a judgment on any- thing which we have not well considered or which is not sufficiently well known. 2d. Prejudice. In this case we form a judgment •in accordance with our wishes and without previous examination. 44 LOGIC. 3d. Our passions. There are impressions vio- lently agitating our mind and forcing it in different directions. 4th. Our senses. The senses have been given to lis by G-od that" we may judge of external bodies, not as they are in themselves, but as they appear to us. 5th. Our imagination. The imagination is that faculty of the mind which pictures to itself material objects that do not affect the senses. Although the human mind is very imperfect, still it would never be deceived if we always acted pru- dently in the investigation of truth, abstaining from judging until the truth shows itself manifestly to the mind. We should then be ignorant of many things, and know others imperfectly ; but we should not err. FOURTH DISSERTATION. ON METHOD . We have now explained the notions of Ideas, the nature of Judgment and of Reasoning, and we have given rules for judging and reasoning correctly. It remains for us to examine in what order we should arrange these mental operations for the investigation and manifestation of truth. This arrangement and order is called Method, or ' ' The way we must go in order to reach the end we have in view." Definition. — Method is that operation of the mind by which we dispose our thoughts in that order which is most suitable for detecting the truth which LOGIC. 45 we do not know and showing it as soon as we know it. Evidently the necessity of method shows the weak- ness of our mind ; but without it progress cannot be made, nor can pleasure be found, in the reading of books or the teaching of masters. Method being the application of the science of logic, is consequently an art ; and this art is ac- quired rather by practice and experience than by precept, and it depends more on the rectitude and attention of our mind than on rules. Division. — Some authors divide method into two kinds, the analytic and the synthetic. This division cannot be accepted ; for, according to it, the analytic method, which is the same as the method of induc- tion, would proceed always by analysis ; but this would too much restrict the method of induction, in which we have to proceed as much by synthesis as by analysis, as experience shows. We must then take a more accurate division. There are two divisions of method, or two methods ; the method of invention, which comprises observa- tion and induction ; and the method of demonstra- tion, or dialectics. 1st Division, the Method of Invention. The difference between observation and induction may be stated thus : When our attention is directed towards a phenomenon or a fact, in order only to know it, we make an observation ; but when that attention is directed to the same fact or phenomenon, in order to discover some law, or to deduce some 46 LOGIC. conclusion from principles, we make, in the first case, an induction, and in the second, a deduction. Observation is consequently a serious attention of the mind, in order to know some fact, which fact may be either exterior or interior. In order to observe well, four operations are ne- cessary : First, attention ; and this attention must be intense, persevering, and free from prejudice ; second, distinct perception of the fact, that is, we must determine well the circumstances of its exist- ence, and its essential elements ; third, analysis, which should be complete, the examination being minute and exhaustive ; and fourth, synthesis, which should also be complete, the recapitulation being made in proper order. These rules ougbt to be fol- lowed not only in observing but also in making ex- periments. Induction, which always supposes previous observ- ation, is an oj>eration of the mind inducing us to affirm of things not observed that which we have observed in similar things. Four conditions are necessary in order that the induction may be good : " First, abstraction ; second, comparison: third, generalization (This, as we have seen, signifies the discovery of a quality common to several similar objects ; and this common quality serves as a distinguishing mark for the class in which all the similar objects are contained. Classi- fication is the formation of these classes, and we may see that generalization affords the materials for classi- fication.); and fourth, induction, properly so called, • which is the extension of the common quality di.s- LOGIC. 47 covered by generalization to other objects of a similar kind. Note. — This method leads lis to a certain knowl- edge of the truth. There are other modes of inves- tigation which lead us, no£ to a sure, but to a more or less probable knowledge of the truth ; these are : analogy, hypothesis and the calculation of proba- bilities. Analogy is an operation of the mind attributing to one object some quality observed in another. Example : A certain medicine has proved to be good for a certain sick person ; analogy would lead us to believe that it would be good for another person sick in like manner. Analogy must be grounded on obvious resem- blance, and the resemblance must have necessary connection with the conclusion which we draw. Hence the science called cranioscopy, and others of that kind, are false. Hypothesis is the supposition of a cause, in order to explain several effects of which the cause is con- cealed. An hypothesis is also called & postulate. Example : The hypothesis of the existence of a neutral electric fluid in all bodies, in order to ex- plain electric phenomena. Hypotheses are very useful, but subject to many serious inconveniences. In order to proceed wisely when we form an hypothesis, we must first examine well the case which we wish to explain by hypothe- sis, and notice all its circumstances ; for the degree of probability of an hypothesis depends on the num.- 48 LOGIC. ber of circumstances which it explains : and, in the second place, we should chose out of those circum- stances that which is most important, and try to explain it by the hypothesis ; hut although our hy- pothesis may explain this most important circum- stance, yet if it he in contradiction to any other circumstance it must he rejected. The calculation of probabilities, so far as it has reference to philosophy, will he spoken of in several other places, especially in Ethics. 2d Division, the Method of Demonstration, or Dialectics. To demonstrate is to prove ; and a demonstration is an argument in which the truth of a proposition is deduced from one or more propositions which are known to be true. The proposition from which the conclusion is drawn is called the principle of the demonstration ; and as this principle may be either sure or probable, the deduction will be accordingly either certain or only probable. The parts of a demonstration are as follows : 1st. The question, or proposition to be demon- strated. When the question is concerning a truth to be demonstrated, it is called a theorem, a thesis, or simply a proposition ; and when it is concerning a truth to be discovered, it is called ^.problem. The question must be defined, divided into its parts, precise, and well arranged. Example : The question is, is the human soul immortal ? Immortality must be defined ; and the question must be divided into its two parts concern- ing internal immortalitv and external immortality. LOGIC. 49 The first part of the question may be passed over, as evident ; and then the real question comes, which is, whether the soul, after the death of the body, will pass to another life, a life without end. We next arrange this question into its two parts, (a) _ whether the soul, on leaving the body, will pass to another life, and (b) whether that life is eternal. 2d. The principle of the demonstration. This principle, or these principles, must be certain and connected with the question. They may be axioms, or facts of experience, or simply postulates. These two first parts, the question and the principle, are called the matter of the demonstration. 3d. The form of the demonstration, or the con- nection of the conclusion with the principle. This connection must first be accurate, that is, nothing should be used in the argument which does not be- long to the question ; and second, it must be clear. The demonstration may be : 1st. Analytical, ascending, going from the ques- tion to some general principle ; or synthetical, de- scending, starting from some general principle and coming to the question. 2d. Direct, or indirect. 3d. A 'priori, the effects being proved by the cause ; or a posteriori, the cause being proved by the effects. 4th. Absolute, resulting from a true principle ; or relative, grounded on a principle admitted as true by our opponent, whether really true or not. This last demonstration does not prove that the conclu- sion is absolutely true, but only that it cannot be 50 LOGIC. denied by those who admit the principle on which it is based : it is therefore called the argumentum ad hominem. FIFTH DISSERTATION. ON CEETITUDB. CHAPTER FIRST. Preliminary Notions — Definitions. Certitude is the firm adhesion of the mind to the truth made known to it. Certitude is at the same time a state and an act of the mind. As a state it may be defined to be, a disposition by which the mind tends to adhere firmly to the known truth. Truth is, " that which is." Truth is either ne- cessary or contingent. Necessary truth is that which cannot but be, and which cannot but be as it is. Such is the truth of the existence of God. A contingent truth is one which, although it may exist, yet might not have existed, or might have existed in a different manner. Truth cannot be known by the intellect unless it is cognoscible. That by which truth is cognoscible, or rendered capable of being perceived by the intel- lect, is called evidence. Evidence has an objective sense, as the term has been used by all good philos- ophers ; although some have pretended that evidence being a perception has only a subjective sense. Certitude is subjective when considered as existing in the mind ; and it is objective when considered as LOGIC. 51 existing in the object, in which case it is the same as truth itself, inasmuch as it is surely known, or inasmuch as it is the object of our certitude. Evidently subjective certitude cannot exist with- out the objective, but objective certitude may exist without the subjective. Evidence is also subjective as well as objective. Objective evidence is that which is perceived by the mind ; it is objective evidence that is defined above. Objective evidence is the visibility of truth, and sub- jective evidence is the vision of truth. Certitude is implicit, that is direct, common or spontaneous, when the mind adheres to the truth from what is only an implicit knowledge of the mo- tion or cause which determines that adhesion. Cer- titude is explicit, philosophical or scientific, when the mind adheres to the truth from an explicit knowledge of the motion or cause which determines that adhesion. Both implicit and explicit certitude are true. Certitude is immediate when the evidence of the truth is intuitive, and mediate when the evidence is discursive, or the result of a course of reasoning. Evidence is itself immediate or intuitive when a truth manifests itself to the mind without the aid of another truth, as in the axiom. The whole is greater than any of its parts ; and it is mediate or discursive when truth is made manifest by the aid of reasoning. Note. — Mediate evidence is formed from that which is immediate, and requires more labor from our minds for its perception. 52 LOGIC. It is not possible by noting the manner in which the perception takes place in our mind to fix the line between intuitive and discursive evidence ; we must, for this purpose, accept the definitions and take them as rules for making the distinction be- tween the two kinds of evidence. A primary truth is one which is intuitively evi- dent ; and a secondary truth is one which is discur- sively evident. Metaphysical certitude is that which is based upon the essence of things, and which can on no hy- pothesis be different from what it is. Physical certitude is that which is based upon the laws of nature, and which cannot be other than it is except by a miracle. Moral certitude is that which is based upon the laws of our moral constitution, and which cannot be otherwise without affecting the condition of human- ity. In regard to the subject, certitude is one and the same for all, though it admits of several degrees' in the clearness of our perception of the truth and in the intensity of our adhesion to it. CHAPTEE SECOND. Of the Criterion of Certitude. A criterion is a sign by which something may be distinguished from everything else ; consequently, the criterion of certitude is the sign by which certi- tude is perfectly distinguished from error. Evident- ly such a sign must exist, but in order to proceed LOUIC. 5d methodically let us first examine what is the crite- rion of truth. I. Proposition. Objective evidence is the criterign of truth. To prove this proposition we proceed as follows : That which is so evidently the characteristic of truth that it cannot be attributed to falsehood, is the criterion of truth. Such a characteristic is objective evidence, — that is, the property by which truth is cognoscible to our minds, and consequently by which truth -is distin- guished from what is not truth ; for if evidence could be attributed to falsehood as well as to truth it would not be that by which what is true is distin- guished from what is not true. Hence, evidence, taken objectively, is the criterion of truth. In order to meet objections that may be brought against this proposition, let us observe that there is a difference between judging and perceiving. We judge sometimes that such a thing is so and so, and perceive afterwards that we have made a mistake. In the first case we judge erroneously of something, which afterwards, on account of evidence, wejperceive exactly as it is. II. The criterion of certitude differs from the criterion of truth. The criterion of truth is the character proper to truth, and consequently some- thing essentially objective ; but the criterion of cer- titude is the character proper to our knowledge, and consequently something both objective and subjec- tive. It is, after all, the criterion of truth applied 54 LOGIC. to our mind, the criterion of truth being the cause of our certitude. In order to determine in what the criterion of certitude consists, let us first see what are the con- ditions or marks which ought to he found in such a criterion. This criterion ought to he : 1st, necessarily con- nected with truth; 2d, known by itself; and 3d, universal, that is, it ought to he the last reason of certitude. Proposition. A clear perception is the only crite- rion of certitude. Argument : That is a criterion of certitude which has the requisite qualities for establishing such a criterion ; But a clear perception has such qualities ; Hence, a clear perception is the criterion of cer- titude. Proof of the minor. 1st. Such a clear perception has a necessary connection with truth ; what we clearly perceive is evident, and it cannot be evident, as we have said, unless it be true. 2d. It is some- thing known by itself, since it is a perception ; for nothing is more known to us than what we see. 3d. It is the last reason of certitude ; for the last reason which we can give for our certitude is this : " I see," ' 1 1 percei ve clearly . ' ' We have said that this clear perception is the only motive of certitude ; for the other motives of certi- tude, of which we shall speak hereafter, are all grounded on this criterion. The last reason which we bring forward is always, "I see clearly/' LOGIC. 55 CHAPTEE THIRD. Of the Existence of Certitude. Some philosophers have altogether denied the existence of certitude, while others have estahlished erroneous systems concerning its attributes. The following are the schools which we shall refute by the exposition of the true philosophical doctrine concerning the existence and the motives of certitude : 1st. Universal or subjective scepticism, also called Pyrrhonism. This denies, or at least doubts, the existence of subjective certitude ; and since one who doubts his own existence may doubt anything this subjective scepticism is called universal scepticism. This was the system of the sophist Pyrrho and his disciples, and also of the " new sceptics,'' a sect that renewed the errors of Pyrrho at the beginning of the Christian era. Among modern philosophers Montaigne, Bayle and Hume have indirectly adhered to the same system. 2nd. Objective scepticism, or Kantism. This is the doctrine of those who accept subjective, but reject objective certitude. It is the system of the modern German school, represented by Kant, Hermes and Fichte. Some French philosophers, of the school of Jouffroy, have accepted the doctrine of Kant with modifications. 3d. Idealism and Empiricism. The idealists are those philosophers who, extolling too much the cer- titude of pure reason, destroy in part the certitude of experience. Berkeley and Mallebranche are the chief representatives of this system. Descartes ad- 5G LOGIC. liered more or less to the system of Mallebranche, and he was also of opinion that the perception of the senses, of itself, could not produce certitude. The empiricists reject the certitude of pure reason, and teach that sensation is the only cause of certi- tude ; they are also called materialists and sensists. Of this class were Condillac and Helvetius, and in our time Augustus Comte, Littre, &c. 4th. Historical scepticism. This is the system of all those who attack historical certitude. It is of two kinds, general, when it rejects all historical certitude, and particular when it refuses to admit some particular historical fact. We find this sys- tem, in regard to its principles, in Bayle, and in the writings of Craig, a Scotch mathematician, and also of Laplace and Lacroix. A branch of this system has been called the theory of Mythism, which is mythism applied to history and religion. Philosophers, or rather infidel writers, try to explain in a mythical way the best authenti- cated facts of history. This system appears in the dangerous writings of Vico, Michelet, Dupuis, Vol- ney, Strauss, Hegel, and, lately, Kenan. 5th. Bationalisin. This is the doctrine of those who do not admit any revealed truth, and try to explain in a natural manner the miracles and mys- teries of revealed religion. We shall see hereafter that revelation is possible, that it is an infallible motive of judging, that the doctrine revealed by God may be perceived by human reason, &c. The system of rationalism is widespread. It has been taught in France by Cousin, Jouffroy and Damiron. LOGIC . 57 6th. Fideism. This is the doctrine of several philosophers who think that genuine certitude can- not be obtained except by faith, either human or divine. As we may see, it is directly opposed to rationalism. To this system belongs (a) the doctrine of Huet, who taught that reason, of itself, cannot give true certitude, but must be assisted by divine faith, and also (b) the doctrine of Lamennais, the author of the famous book "Essai sur 1' Indifference," who was of opinion that what he calls "individual reason" cannot give us true certitude, but that what he calls "general reason" is necessary for this purpose. Lamennais' s system is founded on a vicious circle; for the reasons which determined him to reject indi- vidual reason must also determine him to reject general reason, which, after all, is composed of indi- vidual reasons. The whole system rests upon ob- scure and inaccurate definitions and explanations. It created much excitement in the beginning on account of its novelty and obscurity, and also on account of the talent of its author. 6th. Traditionalism, or the system of those who think that tradition, that is, revelation made to man and handed down by the testimony of men, is necessary to us in order that we should have certain knowledge of truths of the natural order. Dr. Bon- netty was the author of this system, which was con- demned in the provincial council of Rheims, France, in 1853, the condemnation being apj)roved by Pope Pius IX., who, at the same time, condemned the following errors : 58 LOGIC. (a) They err who teach that human reason is, by its nature, inimical to divine revelation, or opposed to it. (b) They err who teach that the force of human reason, in the present condition of our fallen nature, has been almost destroyed, or rendered powerless. (c) They err who teach that no interior power has been left man by which he may acquire truth, or that all truths and notions come to us from exte- rior source, by speech and revelation. (d) They err who affirm that man cannot with his reasoning powers perceive and demonstrate cer- tain truths of the metaphysical and moral order. (e) They err who teach that man cannot naturally admit any metaphysical or moral truth, unless he has first believed by an act of supernatural faith, through divine revelation. (f) They err who do not admit a distinction be- tween the natural divine law and the positive divine law. Having named and described the systems accord- ing to which certitude is either disfigured or its existence totally denied, it now remains that we should affirm and demonstrate it. For this purpose the following propositions are stated and demon- strated : First Proposition. — Certitude Exists. It is certain that certitude exists if there are any truths which the mind accepts without any fear of erring ; for then it perceives these truths clearly, and this clear perception is the criterion of certitude. LOGIC. 59 But there are such truths; for when we say "Two and two are equal to four," the mind accepts the fact without any fear of erring. Hence certitude exists. Second Proposition. The existence of certitude is a fact which cannot he rigidly demonstrated, hut which nevertheless becomes clearly manifest on mere statement or rep- resentation to the mind. Certitude is a fact which cannot he demonstrated, if it he necessary for its demonstration that we should take as a principle that which is to he demonstrated. But such is the case in regard to the existence of certitude ; for to demonstrate it we should first have to take as granted certain premises, — which assump- tion would of itself suppose the existence of certitude ; hut this would he the petitio principii, or begging the question. It is enough then to show or state the existence of certitude ; for this is so clear of itself that no one can seriously doubt it when thus pre- sented to the mind. Third Proposition. No one can doubt the existence of certitude with- out falling into a contradiction. He who supposes in the premises what he wishes to deny in the conclusion, contradicts himself. But such is the case with one denying the existence of certitude ; for his conclusion would be the affirma- tion of his belief in the. non-existence of certitude, and as an affirmation is the expression of a certitude it follows that he contradicts himself. 60 LOGIC. Sceptics bring many objections against tbis tbesis. They say tbat we may find arguments both for and against every proposition, and that therefore we must doubt; and, again, that the human mind is fallible and knows nothing fully, and that for this reason also we should doubt. It is true that we must sometimes doubt, but not always ; and hence certitude does exist. When they add that perhaps life is a dream, we need not stop to answer them. This thesis refutes both subjective and objective scepticism. CHAPTEK FOUETH. Of the Motives of Certitude. A motive, in general, is that which disposes the mind to adhere firmly to some truth. . We have seen that evidence clearly perceived is the general motive of certitude ; but this evidence affects the mind diversely in regard to its adhesion to the truth, according to the different orders of truth. Hence, there are different motives, which we shall examine successively : First Motive. — The Certitude of Pure Reasox. Pure reason, or simply reason, is the faculty by which our mind perceives wbat is absolutely neces- sary. We have already seen what is meant by a necessary truth, and have shown that the evidence which pertains to necessary truth is the evidence of contradiction, that is., an evidence which does not allow us to suppose that the truth is other than it is without contradicting ourselves, or saying implic- LOGIC, 61 itly that the same, thing may be and not be at the same time. Eeason has for its principle all necessary truths, that is all truths which are intuitively evident. These truths are the sources from which all other truths are derived, and it is on this account that they are called the principles of pure reason. These principles have been also called axioms ; and, although some writers have made a distinction be- tween axioms and principles, we shall consider the two words as synonimous. We may define an axiom, or principle of pure reason, to be a necessary and self-evident truth, from which other truths proceed. These principles are : 1st. The principle of iden- tity or essence; namely, "What is, is." This is the same as the principle of contradiction ; namely, " The same thing cannot be and not be at the same time," a principle implicitly contained in every necessary truth. 2nd. The principle of equality and inequality; namely, "Two things which are each equal to a third are equal to each other," and " Two things, of which one is equal to a third, while the other is not equal to this third, are unequal to each other." 3d. The principle of substance ; namely, "The mode supposes the substance." 4th. The principle of casuality ; namely, "That which has a beginning has a cause." These axioms being given, we prove the following Proposition. — Pure reason gives certitude of neces- sary truths. (a) This proposition is clear according to the 62 LOGIC. very definition of reason. Season is a perception ; but if the mind could never adhere to truth, reason would at the same time he a perception and not a perception. It would he a perception according to the hypothesis, and it would not be a perception because we should always doubt ; that is, the same thing would, at the same time, both be and not be, which involves a contradiction. Hence, when reason perceives clearly it gives true certitude. (b) This proposition cannot be seriously opposed, if it be false argument to suppose as true what we attack as false. But such is the case with any ar- gument contrived against the legitimacy of reason, since he who would argue against reason would sup- pose that reasoning is a lawful mode for the attain- ment of certitude. Second Motive. — Consciousness. Consciousness is the interior feeling by which our mind is aware of its present condition or state. Proposition. — Consciousness produces a true certi- tude in regard to our interior feelings and affections. Consciousness gives a true certitude, if there is a necessary connection between it and the truth of the judgments formed by it. But such is the case, since the object and the subject are the same individual ; consequently, consciousness cannot be deceived, although it may deceive. Hence consciousness gives true certitude ; and the judgments formed by it concerning .the appearances of things which have affected it are essentially true, since they express the present state of the soul. LOGIC. G3 Here again, we cannot demonstrate the truth, but simply show it ; for any truth which we could bring forward as a principle of demonstration would rest on reason and on consciousness, which latter is aware of the evidence produced in our' mind. These two motives, reason and consciousness, are, as we see, chained together. Our own existence is, in regard to ourselves, the first truth known of itself, or self-evident. Third Motive. — The Evidence of the Senses. The evidence of the senses is that invincible pro- pensity which induces us to refer our sensations to the bodies which, according to our convictions, have been the causes of them ; and by which, therefore, we judge of the existence of the bodies themselves. Our senses lead us into many errors and illusions, and consequently some philosophers have refused to acknowledge that our senses may give us true certitude. Hence the origin of objective scepticism, of idealism and of traditionalism. Against those philosophers we establish the following Proposition.- — By the evidence of the senses we can judge infallibly of the existence of bodies in general. That* is infallibly true which we are irresistibly forced by nature to believe as true. But we are irresistibly forced by nature to believe in the truth of the existence of bodies in general, which we per- ceive by our senses. Hence, by the evidence of the senses we can judge infallibly of the existence of bodies in general. We prove the minor as follows : A propensity 64 LOGIC. ■which is universal, constant, and irresistible may be considered to be the effect of truth, or the voice of nature, and consequently to exclude every doubt. But that propensity by which we are led to judge of the existence of bodies in general is universal, con- stant and irresistible. It is universal, since we find it in all men ; constant, for all men have it during their whole life ; and irresistible, since we cannot overcome it whatever efforts we make. It is then the voice of nature, the expression of truth. Indirect demonstration. — If there "were no bodies, there would be no difference between the phantoms of our imagination and real bodies ; but we know that this difference does exist, and hence bodies must exist. The evidence of the senses, according to the more probable opinion, gives immediate certitude ; and, consequently, in regard to the strength of the con- viction produced in our mind, the certitude given by the evidence of the senses is equal to that given by reason or by consciousness, from which it differs only in regard to the object, which is metaphysical in one case and physical in the other. The propensity by which we are led to believe in the existence of bodies in general, will also enable us to judge in favor of the existence of bodies and external events, in particular ; for the same argu- ment may be brought forward in this second part of the thesis as in the first. But in this case four con- ditions are required in order that the evidence of the senses may be an infallible motive of certitude : 1st. The organs of sense must be sound and in their, normal condition. LOGIC. G5 2nd. The bodies themselves must he within the limits of the perception of our senses. 3d. Nothing must intervene between the organs of sense and the bodies, so as to interfere with the ordinary laws of their action. 4th. Each of the senses must be exerted upon an object upon which it can properly act. These conditions being observed, the evidence of the senses gives a true certitude in judging of the relative properties of bodies in particular, but not of their essence ; that is, we may judge of them as they appear to us, but not as they are, in themselves. Fourth Motive. — The Consent of Mankind in Things of the Moral Order. By the consent of mankind, we do not mean una- nimity, or metaphysical universality, but that gene- ral consent which is called moral, being the consent of the greater and sounder part of mankind. This consent is the result of common sense, and common sense is nothing else than that general knowledge of first notions or principles which is found in all men. In order that such a consent may be a criterion of certitude, it must be constant, uniform, reasonable,. and not indifferent in regard to its object. Proposition. — The consent of mankind, ivith the conditions prescribed above, is an infallible motive of judging, in regard to several moral truths. 1st. Either such a consent ought to be admitted as a criterion of certitude, or some private opinion should be preferred to it ; but such a preference 66 LOGIC. would be absurd, and therefore the general consent must be admitted. 2nd. A man who would defend an opinion contrary to common sense ought to defend it with irresistible arguments ; but he could not find such arguments, (a) in his reason, for his reason must be in harmony with universal reason ; nor (b) in the consent of mankind, for he rejects this motive of certitude : he would, then, be obliged to admit this consent or be in contradiction with himself. 3d. Direct argument. — It would be absurd to ad- mit that the majority of men, and most sound part of humanity, would deceive, or could be deceived ; but if one should deny the proposition under consid- eration this absurdity would result. Consequently the general consent must be accepted as an expression of the truth. 4th. This consent has been accepted in all ages and at all times as an infallible motive of judging. To show this, it will be sufficient to quote the fol- lowing, from Cicero : ' ' What is established upon the laws of nature must be true, if anything is true ; but a general consent of mankind, which is constant, uniform, and refers to something of great import- ance, as the existence of a Supreme Being, the ne- cessity of worshiping the Deity, &c, is the voice of nature. To solve any objections to this proposition,, we have only to refer to the four conditions already indicated. . LOGIC. 67 Fifth Motive. — The Testimony of Men. As we have already said, we can judge by our senses only of those facts which we have witnessed : for other facts we must rely on the testimony of men. But, by its nature, such testimony is not necessarily infallible ; and we have to examine under what con- ditions it may be considered an infallible motive of certitude. We shall first give some general notions concerning the facts, the witnesses, and the conditions which the testimony must have in order to be an infallible motive of certitude. (A) The facts may be first, contemporaneous or past ; second, public or private ; third, of great or of little importance ; fourth, favorable to the views of the people, or opposed to them ; fifth, clear or ob- scure ; and sixth, natural or supernatural. (B) The witnesses may be, first, eye-witnesses or historical witnesses ; and second, contemporaneous with the events or posterior to them. (C) The testimony, in order to be an infallible motive of certitude, must have the following condi- tions : First, the fact must be possible ; second,, it must be important ; third, there must be several witnesses who were not deceived, who would not deceive, and who could not deceive, even if they wished ; and fourth, these witnesses must speak clearly and be clearly understood. Bayle and his followers have attacked the legiti- macy of the testimony of men as an infallible motive of certitude, and have gone so far as to deny the possibility of establishing with certainty the truth 68 LOGIC. of any historical fact. This system has been called Historical Pyrrhonism ; and it must he rejected, for the following reasons : First, it is as much repug- nant to the nature and moral disposition of men as is Universal Scepticism ; second, it is opposed to reason, which naturally admits that several wit- nesses cannot be deceived in regard to the substance of an important fact, and that they would not and could not deceive : this second part is grounded (a) on the love of truth which is natural to man and (b) on the principle of veracity or the inclination which all men have to speak this truth : the impossibility of deceiving may come from the fact itself, and this takes place when many relate a fact which is hurtful or useless to them, or one concerning which their previous interests are divided ; or the impossibility may come from the nature of the testimony, as when many persons relate the event in the same way, even in the smallest details ; or, again, it may come from the character of the witnesses, and is very clear when they are all honest. Pyrrhonism must, in the third place, be rejected because its acceptance would result in the subversion of religion, of society and of private rights. The truth of religion is established by facts ; while society rests upon a system of customs, laws and forms of government, which, in regard to their origin, are based on tradition, or the testimony of men ; and private rights, so far as their origin is concerned, depend upon titles and documents handed down from generation to generation by the testimony of men. Bayle's doctrine must therefore be rejected. LOGIC. 69 From what has "been said, it is indirectly proved that the testimony of men is sufficient authority for the existence of facts of which we have not been eye- witnesses, including historical facts. We have now to proceed to the direct proof of the proposition that the testimony of men is an infallible motive of certitude in regard to facts. As the facts may be either natural or supernatural, it is evident that the question at issue is a double one ; we shall therefore examine it in two sections. § I. Authority of the testimony of men concerning natural facts. 1st. Proposition.— The testimony of men is an in- fallible motive of judging of contemporaneous facts. We may judge that a fact is true when the wit- nesses have not been deceived, and when they would not and could not deceive. But such is the case with facts which are contemporaneous and of great importance. This minor has been fully developed in the preceding remarks ; therefore the testimony of men is an infallible motive, &c. Note. — When we speak of facts we mean the sub- stance of them, for we may be deceived in regard to secondary circumstances. It is not necessary that the number of the wit- nesses should be great, provided, 1st, that they are honest, 2nd, that their account is uniform, 3d, that they persevere in giving the same testimony at all times, and 4th, that it is evident they are not influ- enced by motives of interest or pleasure, or that their interests are divided, or that the fact is opposed to 70 LOGIC. their interests, or tliat the fact is of such notoriety that any fraud might be detected by other contem- porary witnesses, v TTe may accept the evidence of even one eye-wit- ness when he is entirely trustworthy and when the fact which he relates is in necessary connection with other known facts, and especially when the witness is of great wisdom and virtue, and still more if he attests by miracles the truth of his testimony. The objections to this first proposition, given under different forms, are expressed in the following major: "If the testimony of one man gives only probability, the testimony of several men will give only several probabilities, but no certainty.''' We deny the major ; the amount of probabilities is not to the point : the question is not concerning the value of testimonies taken separately, but concerning the value of testimonies taken together. Consequently the objection is a sophism, which we have called ignorant ia elenclu, or a mistaking of the question at issue. 2d. Proposition.— The testimony of men is some- times an infallible motive of judging of past events. Argument : The testimony of men is an infallible motive of judging of past facts, provided there be several means by which truth comes to us. But such is the case, the means being : tradition, history and monuments. The force of the argument from tradition comes, first, from the moral impossibility that many men have been deceived, or that they have deceived ; this has been sufficiently developed already : and, second, LOGIC. 71 from the argument of prescription, according to which the actual existence of a tradition or a uni- versal custom, the reason for which cannot be given unless the fact on which it is based he accepted, makes it necessary to accept the fact ; for such a tra- dition could not originate in error or falsehood, it not being possible in regard to facts of a serious na- ture and having a serious consequence, that an error should have either suddenly appeared or slowly grown through centuries without some protestation against the falsehood. "We are therefore justified in assenting to the truth of a fact which is attested by tradition : the argument is considered good even in respect to moral obligations. History must be authentic, true and entire. The authenticity of a book may be established by Oral and written tradition, and also by an examination of the book itself. A book is authentic when its style is the same as the style of other books known to be by the same author, and when the contents of the book are in harmony with the known views, doctrines and opinions of the author. An historical work is true when the facts related, whether con- temporaneous or past, are of great importance, are public in their nature, and are not contradicted by any historian of the same period. A history is known to be entire, when a comparison with the original manuscripts, or the first printed editions, shows no omission or alteration of statements in regard to important circumstances. When such a comparison cannot be made, we may judge by the unity of style and plan, and the satisfactory connec- tion of events, that the work is entire. 72 LOGIC. In regard to monuments, it is necessary that they should have a necessary connection with the events commemorated, whether erected at the same time or afterwards. It is objected that a certitude cannot be perfect which is diminishing gradually by the lapse of time and the loss of titles, which rests upon the testi- mony of witnesses less trustworthy than eye-wit- nesses, which becomes less clear as the date of the facts becomes more remote, and which, finally, has often been the source of deception. We answer, that a certitude once established is always a certi- tude ; and though it may not afterwards affect our sensibilities so deeply, nevertheless its intrinsic na- ture is not thereby changed^ and we always have sufficient means to detect a falsification when this takes place. §11. Authority of the testimony of men concern- ing supernatural facts. A supernatural fact differs from a natural fact only with reference to the cause and the manner of its production. In regard to the effect, or the fact itself, it is a natural one. With this explanation, we proceed to demonstrate the following Proposition.- — The testimony of men is an infallible motive of judging of supernatural facts . The truth of supernatural facts may be established by the testimony of men, provided this 'testimony has the same force for proving such facts, that it has for proving natural facts. But such is the case ; for, as we said in the introduction to this proposi- tion, and this assertion is denied by no one, a super- LOGIC. T3 natural fact, in regard to its effect and exterior motive, is only a natural fact, and consequently can be established by similar proof, so that we might here repeat the argument already given in regard to natural facts. The testimony of men is true, when many witnesses relate the same fact, whether this be a miracle or a mere natural fact, provided it be evident that these witnesses have not been de- ceived and have not deceived. Hence the testimony of men is an infallible motive, &c. The objections to this proposition rest upon the following assertion : A miracle is impossible. In this assertion there is an implied contradiction ; for to pretend that all the witnesses to the miracles of our Lord were deceived or did deceive, is to assert a miracle in the moral order greater than the facts which are denied. From what has been said, we may understand what is meant by authority: It is the motive by which we judge of those things which we do not know ourselves. Authority is human when it is the source of human faith or belief, and divine when our adhesion to it constitutes divine or supernatural faith. Sixth Motive. — Memory. Memory is that faculty by which we recall to mind feelings that are past. Proposition. — Memory is an infallible motive of judging of a past state of the mind of which we have a clear recollection. 4 74 LOGIC. This proposition cannot be proved : it can only be explained. I. There is certitude where there is a clear per- ception of a truth .; but by memory, when our recol- lection is distinct, we have such a perception. Hence we have certitude. II. Judgments based upon a universal, constant and irresistible propensity are infallible.* This is admitted by every one ; and were it not true we might doubt of everything, even of God himself. But by memory we form Judgments which are based upon an irresistible, constant and universal pro- pensity ; these judgments are therefore infallible. Hence memory is an infallible motive_, &c. Memory, like consciousness,, produces an imme- diate certitude, and consequently cannot be demon- strated, since the demonstration should rest on memory itself. It is, in fact, by memory that we call to mind the very first principles, the bases, of every demonstration. Seventh Motive. — Induction or Analogy. We reason by induction when we pass from phe- nomena observed and known to phenomena which are neither known nor observed. The following definition of induction may therefore be given : In- duction is the operation by which, from several par- ticular phenomena, the mind concludes the existence of a general law of nature. The principle of induction rests upon the laws of nature. These laws may be summed up in these three axioms : 1st. There exists a constant and gen- LOGIC. Vo- meral order in the things which have been created, that is, in nature ; 2nd. Every natural cause follows a certain order in the production of its effects ; 3d. The same natural cause, placed in the same circum- stances, produces the same effect. We may now proceed to establish the following proposition concerning the principle of induction. Proposition. — A persuasion of the constancy and generality of the laws of nature is an infallible motive of certitude. x What is born with us must be in harmony with the truth, and consequently an infallible motive of certitude ; for if a persuasion natural to our mind could be false, the very constitution of the mind itself would be false, which would be the destruction of all certitude. But a persuasion of the constancy and generality of the laws of nature is innate ; for it is universal, irresistible, and anterior to reason itself, as we see in the case of children, who instinctively avoid what is hurtful ; such a persuasion is therefore an infallible motive of certitude. We have seen, from the exposition of the princi- ples of induction, that there are in nature general laws ; but is it possible to have a true certitude in regard to the existence of the laws of nature in par- ticular ? In order to solve this question we proceed to establish this Proposition. — Induction sometimes gives time certi- tude concerning the laws of nature in particular. We have true certitude when we clearly perceive some truth, and when we may affirm it without any fear of erring. But by induction we know surely, 76 LOGIC. and consequently perceive clearly, the existence of some laws of nature in particular ; for instance, that fire will burn wood, melt lead, &c; and we affirm the existence of these laws without any fear of erring. Certitude, then, sometimes gives us true certitude, 230 CONTENTS. FIRST DISSERTATION.— ON IDEAS. Chapter Ferst. Of Ideas considered as existing in the mind 10 I I. — Division of Ideas 19 § II. — Properties of Ideas 20 § III. — Operations of the mind in regard to Ideas 21 Chapter Second. Of Ideas considered out of the mind , 22 SECOND DISSERTATION.— ON JUDGMENT. Chapter First. Of Judgment considered as existing in the mind 23 Chapter Second. Of Judgment considered as existing out of the mind 24 § I. — Conversion of Propositions 27 \ II. — Opposition of Propositions 28 THIRD DISSERTATION.— ON REASONING:. Chapter First. Of the SyllogiSni and its rules 30 Chapter Secoxd. Of the different sorts of Syllogisms 34 Chapter Third. Of the forms of argument other than the Syllogism 37 Chapter Fourth. Of Sophisms 39 CONTENTS. 231 Chapter Fifth. Of the sources of Sophisms 43 FOURTH DISSERTATION.— ON METHOD. First Division, the Method of Invention 45 Second Division, the Method of Demonstration, or Dialectics 48 FIFTH DISSERTATION— ON CERTITUDE. Chapteb First. Preliminary notions — Definitions 50 Chapter Second. Of the Criterion of Certitude 52 Chapter Third. Of the Existence of Certitude 55 Chapter Fourth. Of the Motives of Certitude 60 1st Motive — The Certitude of pure reason 60 2nd Motive — Consciousness 62 3d Motive — The evidence of the senses 63 4th Motive — The consent of mankind in things of the moral order 65 5th Motive — The testimony of men 67 § I . — Authority of such testimony concerning natural facts 69 § II. — Authority of the same testimony concerning supernatural facts , 72 6th Motive— Memory 73 7th Motive — Induction or analogy 74 Appendix— Probability 76 232 CONTENTS. PART SECOND— METAPHYSICS. FIRST DISSERTATION.— ON ONTOLOGY. Chapter First. Of the notion, essence, possibility of a being in general 82 Chapter Second. Of the causes and the effects of beings 85 Chapter Third. Of the different species of being 89 Article First. — Substance and modification 89, Article Second. — Infinite and finite substances 91 Article Third. — Material and spiritual substances 92 Chapter Fourth. Of the properties of being 93 Chapter Fifth. Of space and time 97 SECOND DISSERTATION.— ON THEODICY. part first.— the existexce of god. Chapter First. Of Atheism 101 § 1st. — Is it prudent to remain indifferent concerning the existence of God? 101 § 2nd. — Are there any evils resulting from the adoption of the theory of the Atheists? 103 I 3d.— Is Theism better than Atheism ? 104 § 4th. — Is Theism safer than Atheism? 104 § 5th. — Is Atheism worse than Polytheism? 104 CONTENTS. 233 Chapter Second. Of the proofs of the existence of God 105 Article First.- — Metaphysical argument 105 Article Second. — Physical argument 109 Article Third. — Moral argument 112 part second.— the attributes of god. Chaptek First. Of the unity of God 116 Article First. — The unity of God proved against the Polytheists 116 Article Second — The unity of God against the Dualists 118 Article Third. — The origin of evil under a being infi- nitely good 119 Chapter Second. Of the eternity of God 121 CnAPTER Third. Of the immutability of God 122 Chapter Fourth. Of the liberty of God 122 Article First. — The existence of the liberty of God 123 Article Second. — Pantheism 124 Article Third. — Optimism 126 Chapter Fifth. Of the omnipotence and independence of God 128 Chapter Sixth. Of the simplicity of God 129 Chapter Seventh. Of the immensity of God ..,.,. 130 234 CONTENTS. Chapter Eighth. Of the knowledge of God 131 Chapter. Ninth. Of the wisdom of God 133 Chapter Tenth. Of the sanctity and veracity of God 134 Chapter Eleventh. Of the goodness and happiness of God 134 Chapter Twelfth. Of the justice of God 135 Chapter Thirteenth. Of the providence of God 135 Article First. — The existence of providence 135 Article Second. — Consequences of the existence of prov- idence in regard to the free actions of men 137 THIRD DISSERTATION.— ON PSYCHOLOGY. part first— experimental psychology. Chapter First. Of sensibility 141 (A) Physical sensibility 142 (a) Organic impressions 143 (b) Sensations 143 (c) Appetite 143 (B) Interior sensibility 144 (a) Personal affections 144 (b) Social desires 145 (c) Sentiments involving some conception of pure reason 145 CONTENTS. 235 Chapter Second. Of the intellect 146 Article First. — The perceptive faculties 146 (A) Experimental perceptions 146 (B) Rational perceptions, or pure reason 147 Article Second. — The reflective faculties — Language... 148 (a) General notions 148 (b) Language considered in relation to thought 149 (c) Origin of language 150 1st. The question of fact 150 2nd. The question of possibility 151 Article Third. — The nature and origin of our ideas . . • 152 1st. The nature of our ideas 152 2nd. The origin of our ideas 153 (a) System of the Sensists 154 (b) The doctrine of innate ideas ^155 (c) The doctrine of the intuition of God 156 Chapter Third. Of activity 157 The freedom of the human soul 158 part second.— rational psychology. Chapter First. Of the nature of the human soul, or of its spirituality 161 Chapter Second. Of the union of the soul with the body 164 Chapter Third. Of the destiny of the soul 169 Chapter Fourth. Of the souls of animals 170 Article First.— The faculties of the souls of animals. . . . 170 Article Second. — The nature and destiny of the souls of animals 172 236 CONTENTS. PART THIRD.— ETHICS ; OR, MORAL PHILOSOPHY. FIRST DISSERTATION.— ON HUMAN ACTIONS IN GENERAL. Chapter First. Of the difference between good and bad actions 178 Art cle First. — The difference between moral good and moral evil 179 Article Second — The obligations of doing good and avoiding evil, or the existence of the natural law 181 Article Third. — The promulgation of this natural law. . 184 Article Fourth. — The immutability of the natural law. . 186 Article Fifth. — The sanction of the natural lav/. 187 Chapter Second. Of the principles of good and bad actions 190 Chapter Third. Rules for distinguishing good from bad actions 191 SECOND DISSERTATION.— ON HUMAN ACTIONS IN PARTICULAR. Chapter First. Of the duties of men towards God < 193 Article First.— The necessity of religious worship 193 Article Second.— The causes which induce men either to neglect or to corrupt the worship of God 197 Chapter Second. Of the duties of man towards himself ■ 197 Article First.— The obligation of preserving the life of the body • • • • 1£ ^ CONTENTS. 237 Article Second. — The obligation of cultivating the facul- ties of the mind 203 (a) The culture of the intellect 203 (b) The culture of the sensibility 207 (c) The culture of the will. 208 Chapter Third. Duties of man towards his fellow men 203 (A) Destiny of man for the state of society ..... 209 (B) Consequences resulting from the state of society: Inequality of conditions in life — right of property 211 DUTIES OF MEN IX THEIR RELATIONS WITH SOCIETY. Article First. — Duties of men in relation to domestic society 215 (a) Conjugal society * 215 (b) Parental society 216 (c) Herile society £16 Article Second. — The duties of men in relation to civil society 216 I. Civil society considered in itself 217 (A) Nature of civil society and its various forms 217 (B) The supreme power in civil society 218 (a) Characteristics and attributes of the supreme power 218 (b) Origin and foundation of the supreme power 218 (c) Means by which it is acquired 219 (d) Causes for which supreme power may be taken from a ruler 221 II. Duties of men considered as members of civil so- ciety 222 Article Third. — Duties of men towards one another. . . . 223 I. Positive duties , 223 II. Negative duties — Duels 223 " ^ . x ^ -, ©~. ,V ^"V •J* ^ ** $> " T A ^ " 3WI V* 5 % O0 x 7 > V A x K ■K->rX = fli <^, C,S ,v- .1* **% v v >- V \ v ^': ,% J\* *' ,; oo^ ^ c5>'