On the other side of the Philosophy of Mind, we have still Aristotle’s science of abstract thought, a Logic, to consider. For hundreds and thousands of years it was just as much honoured as it is despised now. Aristotle has been regarded as the originator of Logic: his logical works are the source of, and authority for the logical treatises of all times; which last were, in great measure, only special developments or deductions, and must have been dull, insipid, imperfect, and purely formal. And even in quite recent times, Kant has said that since the age of Aristotle, logic—like pure geometry since Euclid’s day—has been a complete and perfect science which has kept its place even down to the present day, without attaining to any further scientific improvements or alteration. Although logic is here mentioned for the first time, and in the whole of the history of Philosophy that is to come no other can be mentioned (for no other has existed, unless we count the negation of Scepticism), we cannot here speak more precisely of its content, but merely find room for its general characterization. The forms he gives to us come from Aristotle both in reference to the Notion and to the judgment and conclusion. As in natural history, animals, such as the unicorn, mammoth, beetle, mollusc, &c., are considered, and their nature described, so Aristotle is, so to speak, the describer of the nature of these spiritual forms of thought; but in this inference of the one from the other, Aristotle has only presented thought as defined in its finite application and aspect, and his logic is thus a natural history of finite thought. Because it is a knowledge and consciousness of the abstract activity of pure understanding, it is not a knowledge of this and that concrete fact, being pure form. This knowledge is in fact marvellous, and even more marvellous is the manner in which it is constituted: this logic is hence a work which does the greatest honour to the deep thought of its discoverer and to the power of his abstraction. For the greatest cohesive power in thought is found in separating it from what is material and thus securing it; and the strength shows itself almost more, if thus secured when it, amalgamated with matter, turns about in manifold ways and is seen to be capable of numberless alterations and applications. Aristotle also considers, in fact, not only the movement of thought, but likewise of thought in ordinary conception. The Logic of Aristotle is contained in five books, which are collected together under the name Ὀργανον.
a. The Categories (κατηγορίαι), of which the first work treats, are the universal determinations, that which is predicated of existent things (κατηγορεῖται): as well that which we call conceptions of the understanding, as the simple realities of things. This may be called an ontology, as pertaining to metaphysics; hence these determinations also appear in Aristotle’s Metaphysics. Aristotle (Categor. I.) now says: “Things are termed homonyms (ὁμώνυμα) of which the name alone is common, but which have a different substantial definition (λόγος τῆς οὐσίας); thus a horse and the picture of a horse are both called an animal.”
Thus the Notion (λόγος) is opposed to the homonym; and since Aristotle deduces herefrom τὰ λεγόμενα, of which the second chapter treats, it is clear that this last expression indicates more than mere predication, and is here to be taken as determinate Notions. “Determinate conceptions are either enunciated after a complex (κατὰ συμπλοκήν) or after an incomplex manner (ἄνευ συμπλοκῆς); the first as ‘a man conquers,’ ‘the ox runs,’ and the other as ‘man,’ ‘ox,’ ‘to conquer,’ ‘to run.’” In the first rank of this division Aristotle places τὰ ὄντα, which are undoubtedly purely subjective relations of such as exist per se, so that the relation is not in them but external to them. Now although τὰ λεγόμενα and τὰ ὄντα are again distinguished from one another, Aristotle yet again employs both λέγεται, and ἐστί of the ὄντα, so that λέγεται is predicated of a species, in relation to its particular; ἐστί is, on the contrary, employed of a universal, which is not Idea but only simple. For Aristotle says, “There are predicates (ὄντα) which can be assigned to a certain subject (καθ̓ ὑποκειμένον), yet are in no subject, as ‘man’ is predicated of ‘some certain man,’ and yet he is no particular man. Others are in a subject (ἐν ὑποκειμένῳ ἐστί) yet are not predicated of any subject (I mean by a thing being in a subject, that it is in any thing not as a part, but as unable to subsist without that in which it is), as ‘a grammatical art’ (τὶς γραμματική) is in a subject, ‘the soul,’ but cannot be predicated of any,’ or related as genus to a subject. Some are predicated of a subject (λέγεται) and are in it; science is in the soul and is predicated of the grammatical art. Some again are neither in, nor are predicated of any subject, as ‘a certain man,’ the individual, the one in number; but some of them can be in a subject like ‘a certain grammatical art.’” Instead of subject we should do better to speak of substratum, for it is that to which the Notion necessarily relates, i.e. that which is neglected in abstraction, and thus the individual opposed to the Notion. We can see that Aristotle has the difference of the genus or universal and the individual present to his mind.
The first thing which Aristotle has indicated in the foregoing is thus the genus, which is predicated of a man, but which is not in him, at least not as a particular quality; the brave man, for example, is an actual, but expressed as a universal conception. In formal logic and its conceptions and definitions there is always present opposition to an actual; and the logical actual is in itself something thought, bravery thus being, for example, a pure form of abstraction. This logic of the understanding seeks, however, in its three stages to imitate the categories of the absolute. The conception or definition is a logical actual, and thus in itself merely something thought, i.e. possible. In the judgment this logic calls a conception A the actual subject and connects with it another actual as the conception B; B is said to be the conception and A to be dependent on it—but B is only the more general conception. In the syllogism necessity is said to be simulated: even in a judgment there is a synthesis of a conception and something whose existence is assumed; in the syllogism it should bear the form of necessity, because both the opposites are set forth in a third as through the medius terminus of reason, e.g. as was the case with the mean of virtue (supra, p. 206). The major term expresses logical being and the minor term logical potentiality, for Caius is a mere potentiality for logic; the conclusion unites both. But it is to reason that life first unfolds itself, for it is true reality. What comes second in Aristotle is the universal, which is not the genus, i.e. it is not in itself the unity of universal and particular—nor is it absolute individuality and hence infinitude. This is the moment or predicate in a subject certainly, but it is not absolutely in and for itself. This relation is now expressed through οὐ λέγεται; for ὅ λέγεται is that which, as universal in itself, is likewise infinite. The third is the particular which is predicated: just as science in itself is infinite and thus the genus, e.g. of the grammatical art; but at the same time as universal, or as not individual, it is the moment of a subject. The fourth indicated by Aristotle is what is called immediate conception—the individual. The reservation that something such as a definite grammatical art is also in a subject, has no place here, for the definite grammatical art is not really in itself individual.
Aristotle, himself,[111] makes the following remarks on this matter: “When one thing is predicated (κατηγορεῖται) of another, as of a subject, whatever things are said (λέγεται) of the predicate,” i.e. what is related to it as a universal, “may be also said of the subject.” This is the ordinary conclusion; from this we see, since this matter is so speedily despatched, that the real conclusion has with Aristotle a much greater significance. “The different genera not arranged under one another (μὴ ὑπ̓ ἄλλμλα τεταγμένα), such as ‘animal’ and ‘science,’ differ in their species (διαφοράς). For instance, animals are divided into beasts, bird, fishes—but science has no such distinction. In subordinate genera, however, there may be the same distinctions; for the superior genera are predicated of the inferior, so that as many distinctions as there are of the predicate, so many will there be of the subject.”
After Aristotle had thus far spoken of what is enunciated respecting that which is connected, or the complex, he now comes to “that which is predicated without any connection,” or the incomplex; for as we saw (p. 212) this was the division which he laid down in the second chapter. That which is predicated without any connection he treats of more fully as the categories proper, in what follows; yet the work in which these categories are laid down is not to be regarded as complete. Aristotle[112] takes ten of them; “Each conception enunciated signifies either Substance (οὐσίαν), or Quality (ποιόν), or Quantity (ποσόν),” matter, “or Relation (πρός τι), or Where (ποῦ), or When (ποτέ), or Position (κεῖσθαι), or Possession (ἕχειν), or Action (ποιεῖν), or Passion (πάσχειν). None of these is considered by itself an affirmation (κατάφασις) or a negation (κατάφασις), i.e. none is either true or false.” Aristotle adds to these predicables five post predicaments, but he only ranges them all side by side.[113] The categories of relation are the syntheses of quality and quantity, and consequently they belonged to reason; but in as far as they are posited as mere relation, they belong to the understanding and are forms of finitude. Being, essence, takes the first place in them; next to it is possibility, as accident or what is caused; the two are, however, separated. In substance A is Being, B, potentiality; in the relation of causality A and B are Being, but A is posited in B as being posited in a postulation of A. A of substance is logical Being; it is its essence opposed to its existence, and this existence is in logic mere potentiality. In the category of causality the Being of A in B is a mere Being of reflection; B is for itself another. But in reason A is the Being of B as well as of A, and A is the whole Being of A as well as of B.
Aristotle[114] goes on to speak of Substance; first Substance, “in its strictest (κυριώτατα), first and chief sense” is to him the individual, the fourth class of the divisions enunciated above (pp. 212-214). “Secondary substances are those in which as species (εἴδεσι) these first are contained, that is to say, both these and the genera of these species. Of the subject both name and definition (λόγος) of all things predicated of a subject (τῶν καθ̓ ὑποκειμένον λεγομένον)—of secondary substances—are predicated; for example of the particular man, as subject, both the name and the definition of ‘man’ (living being) are also predicated. But of things which are in a subject (ἐν ὑποκειμένῳ ὄντος) it is impossible to predicate the definition of the” subordinate “subjects, yet with some we predicate the name: the definition of ‘whiteness’ thus is not of the body in which it is, but only the name. All other things however,” besides Definition (λόγος) and “in most cases name, are related to primary substances as subjects” (the individual), “or are inherent in them. Thus without the primary substances none of the rest could exist, for they are the basis (ὑποκεῖσθαι) of all else. Of secondary substances, species is more substance than genus; for it is nearer to the primary substance, and genus is predicated of the species and not the other way.” For species is here the subject, or what does not always require to be something really determined as individual, but which also signifies that which is generally speaking subordinate. “But the species are not more substance one than another, just as in primary substances one is not more substance than the other. Species and genera are likewise, before the rest” (qualities or accidents) “to be called secondary substances: the definition ‘man’ before the fact that he is ‘white’ or ‘runs.’” Abstraction has thus two kinds of objects; ‘man’ and ‘learned’ are both qualities of a certain individual; but the former only abstracts from the individuality and leaves the totality, and is thus the elevation of the individual into the rational, where nothing is lost but the opposition of reflection. “What is true of substances is also true of differences; for as synonyms (συνώνυμα) they have both name and definition in common.”
b. The second treatise is on Interpretation (περὶ ἑρμηνείας); it is the doctrine of judgments and propositions. Propositions exist where affirmation and negation, falsehood and truth are enunciated;[115] they do not relate to pure thought when reason itself thinks; they are not universal but individual.
c. The Analytics come third, and there are two parts of them, the Prior and the Posterior; they deal most fully with proof (ἀπόδειξις) and the syllogisms of the understanding. “The syllogism is a reason (λόγος) in which if one thing is maintained, another than what was maintained follows of necessity.”[116] Aristotle’s logic has treated the general theory of conclusions in the main very accurately, but they do not by any means constitute the universal form of truth; in his metaphysics, physics, psychology, &c., Aristotle has not formed conclusions, but thought the Notion in and for itself.
d. The Topics (τοπικά) which treat of ‘places’ (τόποι) come fourth; in them the points of view from which anything can be considered are enumerated. Cicero and Giordano Bruno worked this out more fully. Aristotle gives a large number of general points of view which can be taken of an object, a proposition or a problem; each problem can be directly reduced to these different points of view, that must everywhere appear. Thus these ‘places’ are, so to speak, a system of many aspects under which an object can be regarded in investigating it; this constitutes a work which seems specially suitable and requisite for the training of orators and for ordinary conversation, because the knowledge of points of view at once places in our hands the possibility of arriving at the various aspects of a subject, and embracing its whole extent in accordance with these points of view (Vol. I. p. 358). This, according to Aristotle, is the function of Dialectic, which he calls an instrument for finding propositions and conclusions out of probabilities.[117] Such ‘places’ are either of a general kind, such as difference, similarity, opposition, relation, and comparison,[118] or special in nature, such as ‘places’ which prove that something is better or more to be desired, since in it we have the longer duration of time, that which the one wise man or several would choose, the genus as against the species, that which is desirable for itself; also because it is present with the more honourable, because it is end, what approximates to end, the more beautiful and praiseworthy, &c.[119] Aristotle (Topic VIII. 2) says that we must make use of the syllogism by preference, with the dialectician, but of induction with the multitude. In the same way Aristotle separates[120] the dialectic and demonstrative syllogisms from the rhetorical and every kind of persuasion, but he counts induction as belonging to what is rhetorical.