CHAPTER III.

THE ‘ORGANON’ OF ARISTOTLE.

Organon,” or “the instrument,” was, as we have said, the name given by Aristotle’s ancient editors to his collective works on Logic. And from this of course Bacon took the title of ‘Novum Organum,’ or “the new instrument,” for his own work, in which the principles and method of modern science were to be developed. We find the ‘Organon’ of Aristotle, as it stands in our editions, to consist of six treatises, respectively entitled ‘Categories,’ ‘On Interpretation,’ ‘First Series of Analytics,’ ‘Second Series of Analytics,’ ‘Topics,’ and ‘Fallacies.’ The two first of these are quite short, both together filling less than 60 pages, but they have been more read and commented on, especially in the middle ages, than all the rest of Aristotle put together. Thousands of scholars, who considered themselves staunch Aristotelians, and as such fought the battle of Nominalism against the Platonists, knew not a word of Aristotle beyond these two treatises. And yet, unfortunately, it is open to considerable doubt whether either of the two was actually written by Aristotle himself.

During the first periods of his life, Aristotle had gradually forged the chief doctrines of his philosophy, and a peculiar set of terms in which they were embodied. When he came to write continuously, in his third period, he often assumed these doctrines and terms as already known, having doubtless given them considerable publicity in oral discourse, if not in essays and short treatises which have now been lost. And thus it frequently happens that we meet with terms and doctrines the meaning of which has to be gathered by implication, as it is never explicitly stated. This is the case with Aristotle’s celebrated doctrine of “the Categories,” to which he repeatedly refers, without ever telling us clearly what position in his system it is meant to hold. Perhaps the simplest account of this doctrine is to say that it sprang from an analysis and classification, made by Aristotle, of the things which men speak of. “Category,” in Greek, meant “speaking of” something. Now, when we speak of anything, we shall find (so Aristotle implies) that we are either speaking of “a substance,”—as, for instance, of a particular man; or else that we are asserting something to be the case about something else. And what we can assert about anything else must be either (1) some “quality” it possesses; (2) its “quantity;” (3) some “relation” in which it stands; (4) the “place” of its existence; (5) the “time” of its existence; (6) its “action,” or what it does; (7) its “passion,” or what is done to it; (8) its “attitude;” or (9) its “habit” or dress. “Substance,” and the above nine modes of speaking of it make up the list of the Ten Categories, as enumerated by Aristotle in his ‘Topics’ (I. 9), and also in the little treatise which professes to treat especially of this subject.

A complete classification of the things which we can speak of must include everything that we can think of, and therefore all the world. But the “Ten Categories” of Aristotle cannot fail to strike us as a curious summary of all things in heaven and earth. Attitude and Habit, or Dress, the 9th and 10th “Categories,” are so exclusively human that we are surprised to find them introduced among genera of far wider application. Some critics say that the list is both redundant in one way and deficient in another. They say that it is redundant because the whole thing might be cut down to two heads—Substance and Relation; and deficient because to none of the “Categories” could mental states and feelings be appropriately assigned. However, Aristotle might perhaps have said that they came under Quality, Action, or Passion, as the case might be. In other parts of his works he gives enumerations of the “Categories,” naming 8, 6, or 4, instead of 10. In one place (‘Met.’ VI. iv.) he names the first five “Categories,” with “Motion” added as a sixth. This last would certainly, according to his view, include the various operations of the mind. On the whole, Aristotle does not appear to have laid much stress on his table of “Categories” as containing an exhaustive division of all things. Probably at first this table was the result of a study in language, made at a time when logical and even grammatical distinctions were in their infancy. Aristotle took the idea of a particular man—say Callias—and called this “Substance,” and then tried how many different kinds of assertions could be made about him; and when he had reduced these to 9, he was perhaps pleased, because “Substance,” and the 9 kinds of assertion made about it, made up 10 “Categories,” and 10 is a perfect number. He afterwards dropped this particular number, and the “Categories” which had been brought in at the end of the list to eke it out. He seems always to have thought a classification of the ways in which we speak of things to be useful for obtaining clear notions. But he was far too sensible to apply his original table of “Ten Categories” as a Procrustean bed for measuring everything in the universe. At the same time it must be confessed that it has been prevalently thought that he did so. Thus Bacon contemptuously accused him of “constructing the world out of his ‘Categories.’” But this arose very much from the fact that the first book of the ‘Organon’ was read out of all proportion more than Aristotle’s great philosophical treatises, and so it came about that the Aristotelian schoolmen attached an exaggerated importance to the table of which it treats, and their sins have been imputed to the Stagirite himself.

The little book before us, which has exercised so much influence, might be described as a logical monograph on the characteristics of some of the “Categories.” After naming the ten, without any account of the manner in which they are arrived at, it discusses to a certain extent the first four only. Then some chapters are appended, which may or may not have been originally a separate paper, on the different ways in which things are called “opposite,” &c. There are two or three hypotheses possible about the book entitled ‘Categories.’ Either it was an early essay written by Aristotle himself, and preserved among his MSS; or it consists of notes from his school, made by some scholar during his lifetime; or else it is the work of some Peripatetic, drawn up after his death, when the making of such tracts had become a fashion. Style is not a sufficient guide in such a question, because the Peripatetics closely imitated the manner of their master. The chief reason for thinking that this book cannot have been his is on account of the extreme nominalism of its doctrine. Aristotle in the ‘Metaphysics’ (VI. vii. 4) asserts that the universal is the “first substance,” while the individual has a secondary and derivative existence; but it is asserted in the ‘Categories’ that the individual is the first substance, and that if individuals were swept away universals would cease to exist. Aristotle may have said this in the early days of his antagonism against Plato;—if so, he seems to have reverted in maturer life to something nearer approaching, though distinguishable from, Plato’s view. There are, however, unphilosophical and un-Aristotelian things in the book — as, for instance, the saying (‘Cat.’ vii. 21) that “if knowledge ceased to exist, the thing known might still remain.” All this looks like the work of a clever but somewhat materialistic follower of the Peripatetic school.

The book which we find standing second in the ‘Organon,’ is the little treatise ‘On Interpretation,’ or, as it might be called, ‘On Language as the interpreter of Thought.’ Its subject is that which in Logic is called the “proposition,”—that is to say, it treats of sentences which affirm or deny something. Modern Logic is divided into three parts, treating respectively of terms, propositions, and syllogisms; and it might for a moment be supposed that the three works, ‘Categories,’ ‘On Interpretation,’ and ‘Analytics,’ correspond to these three divisions. But this is only superficially the case; for the ‘Categories’ does not treat generally of simple terms, it only touches on some characteristics of the names of Substances, Qualities, Quantities, and Relations. And the book, ‘On Interpretation’ is not a prelude to the ‘Analytics;’ it is a separate logical monograph on some of the characteristics of propositions, containing, at the same time, some remarks on words, as fit or unfit to become terms — on indefinite words, “syn-categorematic” words, &c. The great merit of this little treatise is undeniable, especially when considered as containing matter, which though now long accepted and perfectly trite, was in a great measure new in the time of Aristotle, and which served towards the clearing up of many a confusion. All those clear statements about the nature of the proposition; on what is meant by “contrariety” and “contradiction;” on “modal propositions,” or propositions in which the amount of certainty is expressed by the words “necessarily” or “probably;” and other points which the reader will find in the second part of Whately’s ‘Logic,’ are taken almost verbatim from this treatise. There is one point of which Whately was especially fond—namely, that “truth” is the attribute of a proposition or assertion and of nothing else, except in a metaphorical way. This comes from the work before us, where it is laid down as the first characteristic of a proposition that it must be either true or false. A distinction, however, is here drawn, for propositions admit the idea of time. Now, it is the case with regard to propositions of past and present time—for instance, “it is raining,” or “it rained yesterday”—that they must either be true or false; but with regard to future propositions this is not the case; for suppose we say “there will be a battle to-morrow between the Turks and Servians”—this may be probable or improbable, but it is neither true nor false. Obviously, there is no existing fact with which to compare such propositions, and thus to pronounce on their truth or falsehood. But it is argued here that if future propositions, or prophecies, could be pronounced to be certainly true, it would do away with human agency and freewill. This may seem hardly worth enunciating, but it was new at the time when this book was written.

The writer, in considering “modal propositions,” which assert things as necessary, probable, or possible, introduces some discussion on “possibility,” and mentions three heads of the possible. Ordinarily, things in this world are first possible, and then become realised, or actual; but there is another class of things which are always actual, and the possibility in them is only latent or implied—such are the “first substances” which have existed from all eternity; and thirdly, there is a class of. things which always seem possible, and yet can never be realised—for instance, the greatest number or the least quantity, which, while we speak of them, no one can ever say that he has reached. In this passage we find ourselves rather in the region of Metaphysics than of logic, and it is remarkable that here the phrase “first substances” is used, not, as in the ‘Categories,’ to denote ordinary individual existences on the earth, but as a term to denote the eternal, primeval substances which have never not been, such as, in Aristotle’s view, were the stars, and sun, and planets.

The treatise ‘On Interpretation’ was evidently not written at the same time with the ‘Categories,’ or is by a different author, and on a different plane of thought. It is more philosophical and more Aristotelian; it quotes both the ‘Analytics’ and the work ‘On the Soul,’ and therefore cannot be an early production of the Stagirite’s. There is a tradition that Andronicus of Ehodes held that this treatise was not written by Aristotle at all, while Ammonius, a great commentator, argued in favour of its genuineness. Their arguments, which have been preserved, do not seem conclusive one way or the other. Perhaps the only reason against considering this to have been the writing of Aristotle himself is, that while it obviously is as late as the period of his great treatises, it is not in the manner of those treatises. On the whole, it seems safest to conclude that this little book must consist of the notes of Aristotle’s oral teaching upon the elementary bases of Logic, faithfully recording his ideas, and often the very words which he had used.

We may set aside, then, the ‘Categories’ and the ‘Interpretation’ as of doubtful origin, and as at all events not having been originally intended for the place which they have so long held in the forefront of the writings of Aristotle. We turn to that which was, so far as we know, in reality the opening treatise of the Aristotelian Encyclopædia—namely, the ‘Topics;’ and there is some peculiarity to be remarked in the very fact that the subject with which it deals should have been the first to be taken in hand. We know that Aristotle founded, and all but completed, the science of Logic; but we are apt to forget that, when he began to write, the very idea that there was, or could be, such a science had never come into anybody’s head. What philosophers then knew about, and practised, and formulated, was not Logic, or the science of the laws of reasoning, but Dialectic, or the art of discussion. This art was by no means confined to philosophers, but it was the fashion of the day, and was widely and constantly in use in Athenian society, as an intellectual game or fencing-match. The dialogues of Plato give us dramatic specimens of the encounter of wits which might be seen exhibited in numerous Athenian circles from the middle of the fifth century B.C. down to the time of Aristotle. That restless and intellectual people who, three and a half centuries later, were described as “spending their time in nothing else but either to tell or to hear some new thing,” were at an earlier period possessed by an insatiate appetite for discussion and controversy, whether with a view to truth or to mere victory over an opponent. Dialectic then, as an art, was thoroughly recognised, and all but universally practised, yet still the fundamental principles on which it must rest had never yet been properly drawn out, and Aristotle seems to have felt it to be the first task for one who would build up the entire fabric of knowledge, to lay down the laws of Dialectic as the art and science of method. “Dialectic,” he says, “is useful for three things: for exercise of the mind, for converse with other men, and for knowing how to question and handle the principles of philosophy.” And the object of his ‘Topics’ is, as he tells us, “to discover a method by which we shall be able to reason from probabilities on any given question, and to defend a position without being driven to contradict our own assertions.”

Properly speaking, Dialectic, as defined by Aristotle, ought not to come first in the order of sciences, for it is a kind of applied reasoning; it is reasoning applied to that which is not certain, but only probable. Therefore the general principles of reasoning should be drawn out first, and then these should be shown in application to the certainties of science, after which a subordinate branch might be added on reasoning upon probabilities. Aristotle, however, as we have said, did not set out with the conception of Logic, or the science of reasoning, as existing by itself. This only gradually dawned upon him, and it was out of his researches in Dialectic that he was led to develop the idea of Logic. It was in thinking out the rules of Dialectic that Aristotle discovered the principles of the Syllogism, and he was justly proud of the discovery. There are only two passages in all his extant writings in which he speaks of himself: one is that in which he apologises for differing from Plato, “because truth must be preferred to one’s friend;” the other is the passage at the end of the ‘Fallacies’ (which is a sort of appendix to the ‘Topics’), where he refers to his services to Dialectic. “In regard to the process of syllogising,” he says, “I found positively nothing said before me: I had to work it out for myself by long and laborious research.”

The discovery of the structure of the syllogism—that is to say, of the forms in which men do, and must, reason about a great many things in life, was of course very useful for dialectical purposes, both for exposing fallacy in others and for keeping one’s self straight in controversy. But Aristotle, while in the course of writing his treatise on Dialectic, seems to have been impressed with the independent importance of the theory of the Syllogism, and of the necessity for a simple, unapplied Logic. So, after completing seven books of his ‘Topics,’ he dropped the subject, and went on to write his first and second series of ‘Analytics;’ and it was only after he had finished these two great works that he returned to complete the ‘Topics,’ by the addition of an eighth book.

The ‘Topics,’ as their name implies, are the books “treating of places,” and “places” are seats of arguments, or matters in which arguments may be found. Aristotle in a long course of observation and analysis had apparently noted down the heads of reasonings most likely to be available for either attack or defence in dialectical controversy, and he here sets these forth in seven books. His object is to educate the reader to be a skilful dialectician in Athenian arenas. He names the four chief instruments for this purpose: 1st, To make a large collection of propositions—i.e., authoritative sayings, whether of great men or of the many; 2d, To study the different senses in which terms are used; 3d, To detect differences; 4th, To note resemblances. The last three out of these four suggestions are expanded at great length, and Aristotle tells us how to use various logical distinctions, here brought forward for the first time, in pulling to pieces the arguments of an opponent—for instance, how to use the heads of predicables (genus, differentia, proprium, and accidens), or the categories, or the several kinds of logical opposition, for this purpose. The first seven books of the ‘Topics’ scarcely touch at all upon dialectical method, they are quite taken up with a wearisome and seemingly endless list of heads of argumentation. The eighth book, written later, adds some counsel upon the arrangement and marshalling of your arguments, whether you be the respondent defending a thesis, or the interrogator who attacks it. Some of these pieces of advice might be characterised as “dodges;” for instance, when we are told how to conceal from our adversary what we want to prove, till we have got him to admit something which would really imply the point we are aiming at. In Dialectic, as in love and war, almost everything was fair. And yet Aristotle concludes his treatise by saying, “You must, however, take care not to carry on this exercise with every one, especially with a vulgar-minded man. With some persons the dispute cannot fail to take a discreditable turn. When the respondent tries to make a show of escaping by unworthy manœuvres, the questioner on his part must be unscrupulous also in syllogising; but this is a disgraceful scene. To keep clear of such abusive discourse, you must be cautious not to discourse with commonplace, unprepared respondents.”

Athenian Dialectic has passed away, though it had a faint and clumsy revival in the “Disputations” of the middle ages. Even as a preparation for ordinary controversy and debate, it is questionable whether a study of Aristotle’s ‘Topics’ would nowadays be found useful, except so far as the logical distinctions which it contains might sharpen the intellect. But this latter result might equally well be attained by studying the ordinary logics into which all those distinctions have been transplanted. The ‘Topics,’ at the time when it was written, was a work of original penetration, and of vast accumulative labour. Aristotle perhaps ought to have foreseen that it would not be worth his while to reduce Athenian Dialectic to a methodised system, but he did not; and much of what he accumulated for one purpose, came to have great value for another. The chief merit of the ‘Topics’ of Aristotle is, that while intended to be the permanent regulator of Dialectic, it became in reality the cradle of Logic.

Aristotle himself did not use the word “Logic,” which was probably invented afterwards by the Stoics; he spoke of “Analytic,” by which he meant the science of analysing the forms of reasoning. We come now to his ‘Prior and Posterior’ (or First and Second Series of) ‘Analytics.’ In these works he has produced nothing temporary, or of merely antiquarian interest, but an addition to human knowledge as complete in itself, as permanent, and as irrefragable, as the Geometry of Euclid. It is true that Aristotle did not cover and exhaust the entire field in reasoning, just as Euclid did not exhaust the theory of all the properties of space. But so far as he went Aristotle was perfect. His work took its origin out of the examination of dialectical controversies, which, at the time when he wrote, much predominated over all that we should think worthy of the name of physical science, and therefore his aim was limited to the analysis of deductive reasonings. But men still reason deductively, and will always do so; during a great part of life we are employed, not in finding out new laws of nature, but in applying what we knew before, in appealing to general beliefs, or supposed classes of facts, and in drawing our positive or negative conclusions accordingly. To all this process, whenever it occurs, the ‘Analytics’ of Aristotle are as applicable as the principles of Geometry are to every fresh mensuration.

Aristotle invented the word “Syllogism,” for the process of putting two assertions together and out of them deducing a third. This word indeed existed before in Greek literature, but in a general sense, meaning “computation,” “reckoning” or “consideration.” But Aristotle stamped it with the technical meaning which it has ever since borne. In introducing the word, however, it must not be supposed that he introduced, or invented, the process of reasoning to which he applied it, or that he ever pretended to do so. Yet he has been ridiculed, as if this had been the case—as for instance by Locke, who says that it would be strange if God had made men two-legged, and left it to Aristotle to make them rational! The grammarian who first distinguished nouns from verbs and gave them their names, did not invent nouns and verbs, but only called attention to their existence in language; and he who first made rules of syntax was only recording the ways in which men naturally speak and write, not making innovations in language; and so Aristotle with his “Syllogism” only clearly pointed out a process which had always, though unconsciously, been carried on. There is no doubt that, ever since they have possessed reason at all, men have made syllogisms, though, like M. Jourdain making prose, they have for the most part been unaware of it.

The ‘First Series of Analytics’ is entirely devoted to the theory of the Syllogism, with a few collateral discussions. It has no connection with the treatise ‘On Interpretation,’ from which, in phraseology and some points of doctrine, it differs. It is a work which must excite our wonder if we consider the serried mass of observations which it contains, and the absolutely complete way in which it constructs a science and provides for it an appropriate nomenclature. Though countless generations of commentators and school-men have been busy with the ‘Analytics,’ and many modem philosophers have independently treated of Logic, none of them have been able to add a single point of any importance to Aristotle’s theory of deductive reasoning. The ‘Analytics’ are of course not light reading. The style is severely scientific, and concisely expository; not a single grace of ornament, not a superfluous word, is admitted. As Aristotle introduced into these treatises a copious use of the letters A, B, C, to denote the three terms of the syllogism, many parts read like Euclid with the diagrams omitted. It is not necessary to attempt any further description of the contents, or to give here an account of the figures and moods of syllogisms, of conversion of propositions, reduction of syllogisms to the first figure, and the rest, because all these things have found their way into modern compendiums. Are they not written in Aldrich, and Mansel, and Whately, and many other books?

Yet there is one passage of the ‘Prior Analytics’ which we must quote in bare justice to Aristotle. Owing to the too exclusive study of his logical works in the middle ages, and owing to modern writers identifying him with the absurdities of his followers, an idea arose that he, like the least judicious of the schoolmen, thought that all reasoning should be through syllogisms, that nature could be expounded by means of syllogisms, and that syllogisms were a source of knowledge. Hence came protests like that of Bacon, that “the syllogism is unequal to the subtlety of nature.” But nothing could be further from the truth than the whole idea. The reader may be assured that on a point of this kind Aristotle was as sensible as Lord Bacon or John Stuart Mill. After showing that syllogisms are constantly used, and after analysing their form, and showing on what their validity depends, he proceeds to make some remarks on the way in which the major premiss, or general statement in the syllogism, is to be obtained. He says (‘Prior Anal.’ I. xxx.): “There is the same course to be pursued in philosophy, and in every science or branch of knowledge. You must study facts. Experience alone can give you general principles on any subject. This is the case in astronomy, which is based on the observation of astronomical phenomena; and it is the case with every branch of science or art. When the facts in each branch are brought together, it will be the province of the logician to set out the demonstrations in a manner clear and fit for use. When the investigation into nature is complete, you will be able in some cases to exhibit a demonstration; in other cases you will have to say that demonstration is not attainable.” Bacon knew very little Aristotle at first hand; and he cannot have known this passage, else its overwhelming good sense must have stopped many of his remarks. And Aristotle in practice was quite true to the principles here announced. In his ‘Ethics,’ ‘Politics,’ and ‘Physics,’ he does not pedantically drag in the syllogism, but masses facts together, and makes penetrating remarks upon them, and discusses freely, by means of analogy, comparison, and intuition, very much as the ablest writers of the present day would do.

At the same time it must be admitted that, after fully explaining the deductive process, he left the theory of the inductive process, by which general laws are ascertained, almost entirely unexplored. He briefly observes (‘Prior Anal.’ II. xxiii.) that “induction, or the syllogism that arises from it, consists in proving the major term of the middle by means of the minor.” In other words, suppose that we are proving that animals without a gall are long-lived, we do so through our knowledge that man, the horse, and the mule have no gall. Now, in a natural deductive syllogism, we should say—

All animals without a gall are long-lived;
Man, the horse, and the mule, have no gall;
Therefore they are long-lived.

“Long-lived” is here the major term; but in the inductive process we prove it of the middle term, “animals without a gall,” by means of the minor term, “man, the horse, and the mule.” So we require to state the inductive syllogism thus:—

Man, the horse, and the mule are long-lived;
Man, the horse, and the mule are animals without a gall;
Therefore (all) animals without a gall are long-lived.

Aristotle adds that, for the validity of this reasoning, you require to have an intuition in your reason that “man, the horse, and the mule” are, or adequately represent, the whole class of animals without a gall. This is, in fact, the crucial question in the inductive process—Do the instances you have got adequately represent the whole class of similar instances, so as to give you the key to a law of nature? For instance, if it is found that in two or three cases a particular treatment cures the cholera, how can you tell whether the induction is adequate, and that you are justified in asserting, as a general principle, that “such and such a treatment cures the cholera”? Modern logic tells us that a statement of the kind requires verification; and modern writers, such as Bacon, Whewell, and Mill, are at great pains to point out the best methods of verification,—which after all consist in observing and experimenting further; in eliminating all accidental circumstances; in recording, and, if possible, accounting for, the facts which go against your principle; and, finally, in either rejecting it as unproven, or bringing it out as completely established after passing through the ordeal of thorough examination. But the minute and cautious methods of experiment and observation which have gradually come into use among scientific men in modern times were unknown in the days of Aristotle; so it is not to be wondered at that, having so much else to think of, he did not enter upon this field of inquiry. He tells us repeatedly that we must draw our general principles from familiarity with particular facts; but instead of suggesting methods of verification for the validity of those principles, he merely says that they must have the sanction of our reason. It seems to have been his idea that, after gathering facts up to a certain point, a flash of intuition would supervene, telling us, “This is a law.” Such, no doubt, has often been the case, as in Newton’s famous discovery of the law of gravitation from seeing an apple fall. Yet still, in the ordinary course of science, verification ought always to be at hand. And Aristotle, in omitting to provide for this, left a blank in his theory of the acquirement of knowledge.

Aristotle, like Plato, drew a strong line of demarcation between matters in which you can have, and those in which you cannot have, certainty; in other words, between the region of opinion and the region of science. Syllogistic reasoning is applicable both to certainties and probabilities, and as such it had been formally drawn out in the ‘First Analytics.’ Its application by means of Dialectic to matters of opinion had been set forth (in anticipation of the natural order of treatment) in the ‘Topics;’ and now Aristotle proceeded in his ‘Second Series of Analytics’ to write the logic of science, and to exhibit the syllogism as the organ of demonstration.

The attitude of Science is of course different from that of Dialectic. In Dialectic two disputants are required, one of whom is to maintain a thesis, while the other by questioning is to endeavour to draw from him some admission which shall be repugnant to that thesis. In Science, on the other hand, we are not to suppose two disputants, but a teacher and a learner. Thus the ‘Second Analytics’ begin with the words—“All teaching and all intellectual learning arises out of previously existing knowledge.” This points at once to a characteristic of Aristotle’s view of Science. In modem times we associate Science most commonly with the idea of the inductive accumulation of knowledge; and thus we talk of “scientific inquiry;” but Aristotle thinks of Science as deductive and expository, and identifies it with “teaching.” If we look at the specimens of scientific reasoning which he gives us in this book, we shall find that a large proportion of them are taken from Geometry. Next to this, the science most frequently appealed to is Astronomy. But he also mentions Arithmetic, Optics, Mechanics, Stereometry, Harmonics, and Medicine. Sometimes he refers to questions of Natural History, and at other times to questions of Botany. He even applies his scientific method to Ethics, and shows how we are to obtain a definition of the virtue of magnanimity, by observing the leading characteristics of those who are called magnanimous. The Sciences are not classified here, but a comparative scale of perfection among them is indicated; and those are generally laid down to be the most perfect Sciences which are the most elementary and abstract. But with all this leaning towards an ideal of pure and abstract science, it is remarkable how much the Sciences of Observation are considered in this book, and what an enlightened and modern atmosphere breathes through many parts of it.

In developing his idea of Science, Aristotle takes occasion to controvert several opinions which had found vogue in his day. One of these was that everything in Science could be proved. Some men had a notion that you could go back ad infinitum in proving the principles from which your science was deduced: “This principle was true because of that, and that because of something else, and so on for ever.” Others fancied that by a kind of circular reasoning the propositions of Science might all be made to prove each other. “No,” says Aristotle, “Science must commence from something that is not proved at all.” Science must start from im-mediate principles—i.e., principles that cannot be established by any middle term, or, in other words, by any syllogistic reasoning. The axioms of Euclid may give us a specimen of such principles, but, according to Aristotle, each science had its own “primary universal, and immediate principles;” these principles, we are distinctly told, are not innate, but the source of them is the Nous or Reason, which (as we have seen) attains them intuitively, when sufficiently advised, so to speak, by a course of inductive observation. Again, Aristotle brings out here his opposition to Plato’s theory of Ideas: he says, that it is not necessary for Science that the Ideas of things should have a separate existence, but only that universal ideas, or genera, should be capable of being predicated of many individuals. This view seems to correspond with what, in modern times, has been called Conceptualism, and which is a compromise between Nominalism and Realism.

These, however, are metaphysical distinctions. Another point more closely belonging to the Logic of Science is brought out against Plato—namely, the separateness of the Sciences, which follows from each Science having its own appropriate principles. Plato conceived, or appeared to do so, that from the principles of Philosophy (i.e., Metaphysics), right doctrines of Ethics and Politics could be deduced. Hence he said, “It will never be well with the State till the kings are philosophers, or the philosophers kings.” Aristotle, on the other hand, considered the speculative conception of the good, as entertained by a metaphysician, to be quite distinct from the practical conception of the good which occupies the statesman or the moralist. In many ways this demarcation by Aristotle of the separate spheres of different Sciences, gave rise to great clearness of view.

The Logic of Science deals, as might be expected, with the method of defining things,—that is, of saying what they are. But we do not here find the scholastic idea of definition, per genus et differentiam, by stating the class to which a thing belongs, and the characteristic which separates it from the rest of that class. Aristotle takes the more real and thorough position that, to define a thing adequately, you must state its cause. “Science itself,” he says, “is knowledge of a cause.” But what is cause? There are four kinds: the “formal,” which is the whole nature of a thing, being the sum of the other three causes; the “material,” or the antecedents out of which the thing arises; the “efficient,” or motive power; and the “final,” or object aimed at. Speaking generally, the causes most in use for scientific definitions are the efficient and the final. We define an eclipse of the moon by its efficient cause,—the interposition of the earth. We define a house by its final cause,—a structure for the sake of shelter.

One quotation, as a specimen, may conclude these glimpses of the ‘Later Analytics,’ or Aristotle’s Logic of Science: “Nature,” he says, “presents a, perpetual cycle of occurrences. When the earth is wet with rain, an exhalation rises; when an exhalation rises, a cloud forms; when a cloud forms, ram follows, and the earth is saturated: so that the same term recurs after a cycle of transformations. Every occurrence has another for its consequent, and this consequent another, and so on, till we are brought round to the primary occurrence.”

After finishing his ‘Later Analytics,’ Aristotle seems to have taken up Rhetoric, and to have written the main part of his treatise on that subject. He then reverted to Dialectic, and completed his exposition of it by writing his book on ‘Sophistical Confutations,’ which now stands as the conclusion of the ‘Organon.’ The matter treated of in this book has a close connection with that treated of in the ‘Topics.’ The practice of Dialectic at Athens had given scope to a class, which gradually arose, of professional and paid disputants, or professors and teachers of the art of controversy. This professional class, who were called the “Sophists,” got a bad name in antiquity; and Aristotle treats them disparagingly as mere charlatans. Thus while Contentiousness is arguing for victory, he describes Sophistry as arguing for gain. The Sophist, according to Aristotle, tried to confute people and make them look foolish, employing for this purpose, not fair arguments, but quibbles and fallacies; and all this was done in order to be thought clever and to get pupils. An amusing picture of this sort of process is given in Plato’s dialogue called ‘Euthydemus,’ where two professionals are represented as bamboozling with verbal tricks an ingenuous youth, until Socrates by his dialectical acumen and superior wit rescues the victim from his tormentors, and turns the tables upon them. The following is a specimen of the “sophistical confutations” in ‘Euthydemus:’ “Who learn, the wise or the unwise?” “The wise,” is the reply; given with blushing and hesitation. “And yet when you learned you did not know and were not wise.” “Who are they who learn the dictation of the grammar-master, the wise boys or the foolish boys?” “The wise.” “Then after all the wise learn.” “And do they learn what they know or what they do not know?” “The latter.” “And dictation is a dictation of letters?” “Yes.” “And you know letters?” “Yes.” “Then you learn what you know.” “But is not learning acquiring knowledge?” “Yes.” “And you acquire that which you have not got already?” “Yes.” “Then you learn that which you did not know.” [1]

Plato’s picture is, doubtless, a caricature, exaggerating the fallacious practice of the lower sort of professional disputants to be met with in those days at Athens. But the dialogue ‘Euthydemus’ seems to have suggested to the scientific mind of Aristotle the idea of classifying all the fallacies that had been or could be employed in argument, and the ‘Sophistical Confutations’ is the result. To the value of this book it makes no difference how far the quibbles and deceptive reasonings adduced had been actually used by certain definite individuals for mercenary purposes, or whether, historically speaking, the professional “Sophists” of Greece were as bad as Plato had represented them. Putting the “Sophists” of Greece quite out of consideration, fallacy, whether voluntary or involuntary, will still remain, and is still always incident to human reasoning. And this it is which Aristotle undertakes to classify. It might be thought that errors in reasoning were infinite in number, and incapable of being reduced to definite species; but this is not the case, because every unsound reasoning is the counterfeit of some sound reasoning, and only gains credence as such. But the forms of sound reasoning are strictly limited in number, and therefore the forms of fallacy must be limited also. Ambiguity in language is, of course, one main source of fallacy; and fallacy arises whenever either the major, the minor, or the middle term of a syllogism is used with a double meaning. It will be seen above that the quibblers in ‘Euthydemus’ employ the terms “wise,” “learn,” and “know” in double senses so as to cause confusion.

Aristotle’s account of the fallacies attaching to syllogistic or deductive reasoning is complete and exhaustive, and has been the source of all that has subsequently been written on the subject. The fallacies of amphibolia, accidens, a dicto secundum quid ad dictum simpliciter, ignoratio elenchi, petitio principii, consequens, non causa pro causa, and plures interrogationes have become the property of modern times, with names Latinised from those by which Aristotle first distinguished them; and in Whately’s, and other compendiums, they may be found duly explained. It is true that Aristotle does not investigate the sources of error attaching to the inductive process; the “idols of the tribe” and “of the den” he left for Bacon to denounce; and the fallacies of “inspection,” “colligation,” and the rest to be supplied by Whewell and Mill. But with regard to this, it must be observed that he treats of the doctrine of Fallacies as supplementary, not to the Logic of Science, but to Dialectic. All through the ‘Sophistical Confutations’ we have a background of Hellenic disputation,—the questioner and the answerer are hotly engaged, and the bystanders keenly interested,—Aristotle in analysing fallacy is primarily contributing artistic rules for the conduct of the game. The local and temporary object has passed away, and much of the original importance of the book has accordingly been lost; but the distinctions which were here for the first time drawn out have passed over into Logic, and have doubtless contributed somewhat to clear up the thought and language of Europe.


  1. See Professor Jowett’s Introduction to ‘Euthydemus’ in his ‘Dialogues of Plato,’ i.p. 184, 2d ed.