1. 646KὍτι μὲν οὖν ἕκαστον τῶν ἐνεργείᾳ θερμῶν καὶ ψυχρῶν καὶ ξηρῶν καὶ ὑγρῶν ἢ τῷ τὴν ἄκραν δεδέχθαι ποιότητα τοιοῦτον εἶναί φαμεν ἢ ἐπικρατήσει τινὸς ἐξ αὐτῶν ἢ πρὸς τὸ σύμμετρον ὁμογενὲς παραβάλλοντες ἢ πρὸς ὁτιοῦν τῶν ἐπιτυχόντων, ἔμπροσθεν εἴρηται. δέδεικται δὲ καί, ὡς ἄν τις μάλιστα δύναιτο διαγιγνώσκειν ἀκριβῶς αὐτά. λοιπὸν δ’ ἂν εἴη περὶ τῶν δυνάμει τοιούτων διελθεῖν αὐτὸ πρότερον ἐξηγησαμένους τοὔνομα τί ποτε σημαίνει τὸ δυνάμει.
Σύντομος δὲ καὶ ῥᾴστη καὶ σαφὴς ἡ ἐξήγησις. ὃ γὰρ ἂν | 647Kὑπάρχῃ μὲν μήπω τοιοῦτον, οἷον λέγεται, πέφυκε δὲ γενέσθαι τοιοῦτον, δυνάμει φαμὲν ὑπάρχειν αὐτό, λογικὸν μὲν τὸν ἄρτι γεγενημένον ἄνθρωπον, πτηνὸν δὲ τὸν ὄρνιν, καὶ θηρατικὸν μὲν τὸν κύνα, ταχὺν δὲ τὸν ἵππον, ὅπερ ἔσεσθαι πάντως ἕκαστον αὐτῶν μέλλει μηδενὸς τῶν ἔξωθεν ἐμποδὼν αὐτῷ γενομένου, τοῦθ’ ὡς ὂν ἤδη λέγοντες. ὅθεν οἶμαι καὶ δυνάμει ταῦτα πάντα φαμὲν ὑπάρχειν, οὐκ ἐνεργείᾳ. τέλειον μὲν γάρ τι καὶ ἤδη παρὸν ἡ ἐνέργεια·
1. 646KIt was said before that each of the things that are hot, cold, dry, and wet in actuality, we say are so either by having received such a quality to an extreme degree, or through one of them dominating, or by comparison with the median of the same class, or whatever of these has happened. It has also been shown how someone is most able to recognize these accurately. It now remains to go over such things “in potentiality” (potentially),1 having first explained this term and what it sometimes signifies.
The explanation is brief, very easy, and clear. For if something | 647Kis not yet such a thing as it is called, but is of a nature to become such a thing, we say this exists “in potentiality”—a human that has just come into being is “rational” [in this sense], a bird “flying,” a dog “hunting,” or a horse “swift.” What each of these will, in all likelihood, become in the future, providing nothing external arises to prevent it, we speak as already existing. This is why, I think, we say all these things exist potentially but not actually. For “actuality” is said of something that is complete