Note 254 — V.

Topica, V. ix. p. 138, b. 27-37. οἷον ἐπεὶ ὁ εἴπας ἀέρος ἴδιον τὸ ἀναπνευστόν τῇ δυνάμει μὲν ἀπέδωκε τὸ ἴδιον (τὸ γὰρ τοιοῦτον ἴδιον οἷον ἀναπνεῖσθαι ἀναπνευστόν ἐστιν), ἀποδέδωκε δὲ καὶ πρὸς τὸ μὴ ὃν τὸ ἴδιον· καὶ γὰρ μὴ ὄντος ζῴου, οἷον ἀναπνεῖν πέφυκε τὸν ἀέρα, ἐνδέχεται ἀέρα εἶναι· οὐ μέντοι μὴ ὄντος ζῴου δυνατόν ἐστιν ἀναπνεῖν· ὥστ’ οὐδ’ ἀέρος ἔσται ἴδιον τὸ τοιοῦτον οἷον ἀναπνεῖσθαι, τότε ὅτε ζῴον οὐκ ἔσται τοιοῦτον οἷον ἀναπνεῖν. οὐκ ἂν οὖν εἴη ἀέρος ἴδιον τὸ ἀναπνευστόν.

Respirability (the proprium here discussed) being a relative term, Aristotle demands that the correlate thereof shall be named and included in setting out the proprium. If this be not done, a refutative argument may be drawn from such omission — that the respondent was not aware of the relativity. We may remark here that this objection is founded on a bad or incomplete specification of the proprium in question: it is not an objection against the reality of that proprium itself, if carefully described. The objection belongs to that class which Aristotle had discussed before, at the commencement of Book V.