Galen also recognizes five Categories; but not the same five as Plotinus. He makes a new list, formed partly out of the Aristotelian ten, partly out of the Stoic four:— Οὐσία, ποσόν, ποιόν, πρός τι, πρό τι πὼς ἔχον.[140]
[140] Schol. ad Categor. p. 49, a. 30.
The latter portion of this Aristotelian treatise, on the Categories or Predicaments, consists of an Appendix, usually known under the title of ‘Post-Predicamenta;’[141] wherein the following terms or notions are analysed and explained — Opposita, Prius, Simul, Motus, Habere.
[141] Andronikus and other commentators supposed the Post-Predicamenta to have been appended to the Categoriæ by some later hand. Most of the commentators dissented from this view. The distinctions and explanations seem all Aristotelian.
Of Opposita, Aristotle reckons four modes, analogous to each other, yet not different species under the same genus:[142] — 1. Relative-Opposita — Relatum and Correlatum. 2. Contraria. 3. Habitus and Privatio. 4. Affirmatio and Negatio.
[142] Categ. p. 11, b. 16: περὶ δὲ τῶν ἀντικειμένων, ποσαχῶς εἴωθεν ἀντικεῖσθαι ῥητέον. See Simpl. in Schol. p. 81, a. 37-b. 24. Whether Aristotle reckoned τὰ ἀντικείμενα a true genus or not, was debated among the commentators. The word ποσαχῶς implies that he did not; and he treats even the term ἐναντία as a πολλαχῶς λεγόμενον, though it is less wide in its application than ἀντικείμενα, which includes Relata (Metaphys. I. p. 1055, a. 17). He even treats στέρησις as a πολλαχῶς λεγόμενον (p. 1055, a. 34).
Αἱ ἀντιθέσεις τέσσαρες, the four distinct varieties of τὰ ἀντικείμενα are enumerated by Aristotle in various other places:— Topic. ii. p. 109, b. 17; p. 113, b. 15; Metaphys. I. p. 1055, a. 38. In Metaphys. Δ. p. 1018, a. 20, two other varieties are added. Bonitz observes (ad Metaph. p. 247) that Aristotle seems to treat this quadripartite distribution of Opposita, “tanquam certum et exploratum, pariter ac causarum numerum,â€� &c.
These four modes of opposition have passed from the Categoriæ of Aristotle into all or most of the modern treatises on Logic. The three last of the four are usefully classed together, and illustrated by their contrasts with each other. But as to the first of the four, I cannot think that Aristotle has been happy in the place which he has assigned to it. To treat Relativa as a variety of Opposita, appears to me an inversion of the true order of classification; placing the more comprehensive term in subordination to the less comprehensive. Instead of saying that Relatives are a variety of the Opposite, we ought rather to say that Opposites are varieties of the Relative. We have here another proof of what has been remarked a few pages above; the narrow and inadequate conception which Aristotle formed of his Ad Aliquid or the Relative; restricting it to cases in which the describing phrase is grammatically elliptical.[143] The three classes last-mentioned by Aristotle (1. Contraria, 2. Habitus and Privatio, 3. Affirmatio and Negatio) are truly Opposita; in each there is a different mode of opposition, which it is good to distinguish from the others. But the Relatum and its Correlatum, as such, are not necessarily Opposite at all; they are compared or conceived in conjunction with each other; while a name, called relative, which connotes such comparison, &c., is bestowed upon each. Opposita fall under this general description, as parts (together with other parts not Opposita) of a larger whole. They ought properly to be called Opposite-Relativa: the phrase Relative-Opposita, as applied to Relatives generally, being discontinued as incorrect.[144]
[143] Categ. p. 11, b. 24.