[20] Aristot. Metaph. E. p. 1026, b. 21: φαίνετας γάρ τό συμβεβηκὸς ἐγγύς τι τοῦ μὴ ὄντος.
There cannot be a stronger illustration of the difference between the Platonic and the Aristotelian point of view, than the fact that Plato applies the same designation to all particular objects of sense — that they are only midway between Entia and Non-Entia (Republic, v. pp. 478-479).
We thus have the counter-theory of Aristotle against the Platonic Realism. Instead of separate Universal Substances, containing in themselves full reality, and forfeiting much of that reality when they faded down into the shadowy copies called Particulars, he inverts the Platonic order, announces full reality to be the privilege of the Particular Sensible, and confines the function of the Universal to that of a predicate, in or along with the Particular. There is no doctrine that he protests against more frequently than the ascribing of separate reality to the Universal. The tendency to do this, he signalizes as a natural but unfortunate illusion, lessening the beneficial efficacy of universal demonstrative reasoning.[21] And he declares it to be a corollary from this view of the Particular as indispensable subject along with the Universal as its predicate — That the first principles of Demonstration in all the separate theoretical sciences must be obtained by Induction from particulars: first by impressions of sense preserved in the memory; then by multiplied remembrances enlarged into one experience; lastly, by many experiences generalized into one principle by the Noûs.[22]
[21] Aristot. Analyt. Poster. I. xxiv. p. 85, a. 31, b. 19.
[22] See the concluding chapter of the Analytica Posteriora.
A similar doctrine is stated by Plato in the Phædon (p. 96, B) as one among the intellectual phases that Sokrates had passed through in the course of his life, without continuing in them.
While Aristotle thus declares Induction to be the source from whence Demonstration in these separate sciences draws its first principles, we must at the same time acknowledge that his manner of treating Science is not always conformable to this declaration, and that he often seems to forget Induction altogether. This is the case not only in his First Philosophy, or Metaphysics, but also in his Physics. He there professes to trace out what he calls beginnings, causes, elements, &c., and he analyses most of the highest generalities. Yet still these analytical enquiries (whatever be their value) are usually, if not always, kept in subordination to the counter-theory that he had set up against the Platonic Realism. Complete reality resides (he constantly repeats) only in the particular sensible substances and sensible facts or movements that compose the aggregate Kosmos: which is not generated, but eternal, both as to substance and as to movement. If these sensible substances disappear, nothing remains. The beginnings and causes exist only relatively to these particulars. Form, Matter, Privation, are not real Beings, antecedent to the Kosmos, and pre-existent generators of the substances constituting the Kosmos; they are logical fragments or factors, obtained by mental analysis and comparison, assisting to methodize our philosophical point of view or conception of those substances, but incapable of being understood, and having no value of their own, apart from the substances. Some such logical analysis (that of Aristotle or some other) is an indispensable condition even of the most strictly inductive philosophy.
There are some portions of the writings of Aristotle (especially the third book De Animâ and the twelfth book of the Metaphysica) where he appears to lose sight of the limit here indicated; but, with few exceptions, we find him constantly remembering, and often repeating, the great truth formulated in his Categories: that full or substantive reality resides only in the Hoc Aliquid, with its predicates implicated with it, and that even the highest of these predicates (Second Substances) have no reality apart from some one of their particulars. We must recollect that, though Aristotle denies to the predicates a separate reality, he recognizes in them an adjective reality, as accompaniments and determinants: he contemplates all the ten Categories as distinct varieties of existence.[23] This is sufficient as a basis for abstraction, whereby we can name them and reason upon them as distinct objects of thought or points of view, although none of them come into reality except as implicated with a sensible particular. Of such reasoning Aristotle’s First Philosophy chiefly consists; and he introduces peculiar phrases to describe this distinction of reason between two different points of view, where the real object spoken of is one and the same. The frequency of the occasions taken to point out that distinction marks his anxiety to keep the First Philosophy in harmony with the theory of Reality announced in his Categories.
[23] Aristot. Metaphys. Δ. p. 1017, a. 23: ὀσαχῶς γὰρ λέγεται (τὰ σχήματα τῆς κατηγορίας), τοσαυταχῶς τὸ εἶναι σημαίνει.
The Categories of Aristotle appear to have become more widely known than any other part of his philosophy. They were much discussed by the sects coming after him; and, even when not adopted, were present to speculative minds as a scheme to be amended.[24] Most of the arguments turned upon the nine later Categories: it was debated whether these were properly enumerated and discriminated, and whether the enumeration as a whole was exhaustive.