Note 121 — Chapter III · CATEGORIÆ.

Bonitz has an instructive note upon Form and Matter, the metaphysical constituents of Prima Substantia, Hoc Aliquid, Sokrates, Kallias (see Aristot. Metaphys. Z. p. 1033, b. 24), which illustrates pertinently the relation between Predicate and Subject, the logical constituents of the same σύνολον. He observes (not. p. 327, ad Aristot. Metaph. Z. p. 1033, b. 19). “Quoniam ex duabus substantiis, quæ quidem actu sint, nunquam una existit substantia, si et formam et materiem utrumque per se esse poneremus, nunquam ex utroque existeret res definita ac sensibilis, τόδε τι. Ponendum potius, si recte assequor Aristotelis sententiam, utrumque (Form and Matter) ita ut alterum exspectet, materia ut formæ definitionem, forma ut materiam definiendam, exspectet, neutra vero per se et absolute sit.” What Bonitz says here about Matter and Form is no less true about Subject and Predicate: each is relative to the other — neither of them is absolute or independent of the other. In fact, the explanation given by Aristotle of Materia (Metaph. Z. p. 1028, b. 36) coincides very much with the Prima Essentia of the Categories, if abstracted from the Secunda Essentia. Materia is called there by Aristotle τὸ ὑποκείμενον, καθ’ οὗ τὰ ἄλλα λέγεται. ἐκεῖνο δ’ αὐτὸ μηκέτι κατ’ ἄλλο — λέγω δ’ ὕλην ἣ καθ’ αὑτὴν μήτε τὶ μήτε ποσὸν μήτε ἄλλο μηθὲν λέγεται οἷς ὥρισται τὸ ὄν (p. 1029, a. 20). ἔστι γάρ τι καθ’ οὗ κατηγορεῖται τούτων ἕκαστον, ᾧ τὸ εἶναι ἕτερον καὶ τῶν κατηγοριῶν ἑκάστῃ· τὰ μὲν γὰρ ἄλλα τῆς οὐσίας κατηγορεῖται, αὕτη δὲ τῆς ὕλης.

Aristotle proceeds to say that this Subject — the Subject for all Predicates, but never itself a Predicate — cannot be the genuine οὐσία, which must essentially be χωριστὸν καὶ τὸ τόδε τι (p. 1029, a. 28), and which must have a τί ἦν εἶναι (1029, b. 2). The Subject is in fact not true οὐσία, but is one of the constituent elements thereof, being relative to the Predicates as Correlata: it is the potentiality for Predicates generally, as Materia is the potentiality for Forms.