Note 98 — Chapter XXVIII · THEÆTETUS.

Plato, Theætêt. p. 186 A. καλὸν καὶ αἰσχρόν, καὶ ἀγαθὸν καὶ κακόν. Καὶ τούτων μοι δοκεῖ ἐν τοῖς μάλιστα πρὸς ἄλληλα σκοπεῖσθαι τὴν οὐσίαν, ἀναλογιζομένη (ἡ ψυχὴ) ἐν ἑαυτῇ τὰ γεγονότα καὶ τὰ παρόντα πρὸς τὰ μέλλοντα.

Base and honourable, evil and good, are here pointed out by Sokrates as most evidently and emphatically relative. In the train of reasoning here terminated, Plato had been combating the doctrine Αἴσθησις = Ἐπιστήμη. In his sense of the word αἴσθησις he has refuted the doctrine. But what about the other doctrine, which he declares to be a part of the same programme — Homo Mensura — the Protagorean formula? That formula, so far from being refuted, is actually sustained and established by this train of reasoning. Plato has declared οὐσία, ἀληθεία, ἐναντιότης, ἀγαθόν, κακόν, &c., to be a distinct class of Objects not perceived by Sense. But he also tells us that they are apprehended by the Mind through its own working, and that they are apprehended always in relation to each other. We thus see that they are just as much relative to the concipient mind, as the Objects of sense are to the percipient and sentient mind. The Subject is the correlative limit or measure (to use Protagorean phrases) of one as well as of the other. This confirms what I observed above, that the two doctrines, 1. Homo Mensura, 2. Αἴσθησις = Ἐπιστήμη, — are completely distinct and independent, though Plato has chosen to implicate or identify them.