§9.2ἐπεὶ δʼ αἱ μὲν ἐν τοῖς ἀψύχοις ἐνυπάρχουσιν ἀρχαὶ τοιαῦται, αἱ δʼ ἐν τοῖς ἐμψύχοις καὶ ἐν ψυχῇ καὶ τῆς ψυχῆς ἐν τῷ λόγον ἔχοντι, δῆλον ὅτι καὶ τῶν δυνάμεων αἱ μὲν ἔσονται ἄλογοι αἱ δὲ μετὰ λόγου·
Since some of these principles are inherent in inanimate things, and others in animate things, and in the soul, and in the rational part of the soul, it is clear that of potentialities too, some will be irrational and others accompanied by reason.
διὸ πᾶσαι αἱ τέχναι καὶ αἱ ποιητικαὶ ἐπιστῆμαι δυνάμεις εἰσίν· ἀρχαὶ γὰρ μεταβλητικαί εἰσιν ἐν ἄλλῳ ἢ ᾗ ἄλλο.
Therefore all arts and productive sciences are potentialities; for they are principles of change in another thing or in the thing itself qua other.
καὶ αἱ μὲν μετὰ λόγου πᾶσαι τῶν ἐναντίων αἱ αὐταί, αἱ δὲ ἄλογοι μία ἑνός, οἷον τὸ θερμὸν τοῦ θερμαίνειν μόνονʼ ἡ δὲ ἰατρικὴ νόσου καὶ ὑγιείας.
And all those which are accompanied by reason are the same potentialities for contrary effects, while each of the irrational ones is for one effect; e.g., heat is only for heating, but the medical art is for both disease and health.
αἴτιον δὲ ὅτι λόγος ἐστὶν ἡ ἐπιστήμη, ὁ δὲ λόγος ὁ αὐτὸς δηλοῖ τὸ πρᾶγμα καὶ τὴν στέρησιν, πλὴν οὐχ ὡσαύτως, καὶ ἔστιν ὡς ἀμφοῖν ἔστι δʼ ὡς τοῦ ὑπάρχοντος μᾶλλον, ὥστʼ ἀνάγκη καὶ τὰς τοιαύτας ἐπιστήμας εἶναι μὲν τῶν ἐναντίων, εἶναι δὲ τοῦ μὲν καθʼ αὑτὰς τοῦ δὲ μὴ καθʼ αὑτάς·
The reason for this is that science is a formula (logos), and the same formula discloses both the thing and its privation, though not in the same way, and is in one sense of both, and in another sense rather of the positive state; so that such sciences must indeed be of contraries, but of the one essentially and of the other not essentially.
καὶ γὰρ ὁ λόγος τοῦ μὲν καθʼ αὑτὸ τοῦ δὲ τρόπον τινὰ κατὰ συμβεβηκός· ἀποφάσει γὰρ καὶ ἀποφορᾷ δηλοῖ τὸ ἐναντίον· ἡ γὰρ στέρησις ἡ πρώτη τὸ ἐναντίον, αὕτη δὲ ἀποφορὰ θατέρου.
For indeed the formula is of the one essentially, but of the other in a way accidentally; for it discloses the contrary by negation and removal; for the primary privation is the contrary, and this is the removal of the other.
ἐπεὶ δὲ τὰ ἐναντία οὐκ ἐγγίγνεται ἐν τῷ αὐτῷ, ἡ δʼ ἐπιστήμη δύναμις τῷ λόγον ἔχειν, καὶ ἡ ψυχὴ κινήσεως ἔχει ἀρχήν, τὸ μὲν ὑγιεινὸν ὑγίειαν μόνον ποιεῖ καὶ τὸ θερμαντικὸν θερμότητα καὶ τὸ ψυκτικὸν ψυχρότητα, ὁ δʼ ἐπιστήμων ἄμφω.
But since contraries do not occur in the same thing, and science is a potentiality by virtue of having a formula, and the soul has a principle of motion, [therefore] while that which is healthy produces only health, and that which heats produces only heat, and that which cools produces cold, the scientific person produces both.
λόγος γάρ ἐστιν ἀμφοῖν μέν, οὐχ ὁμοίως δέ, καὶ ἐν ψυχῇ ἣ ἔχει κινήσεως ἀρχήν· ὥστε ἄμφω ἀπὸ τῆς αὐτῆς ἀρχῆς κινήσει πρὸς ταὐτὸ συνάψασα·
For there is a formula of both, though not in the same way, and it is in a soul which has a principle of motion; so that the soul will move both from the same principle, having connected them to the same thing.
διὸ τὰ κατὰ λόγον δυνατὰ τοῖς ἄνευ λόγου δυνατοῖς ποιεῖ τἀναντία· μιᾷ γὰρ ἀρχῇ περιέχεται, τῷ λόγῳ.
Therefore, things capable according to reason produce contrary effects to those capable without reason; for they are held together by one principle, namely the formula.
φανερὸν δὲ καὶ ὅτι τῇ μὲν τοῦ εὖ δυνάμει ἀκολουθεῖ ἡ τοῦ μόνον ποιῆσαι ἢ παθεῖν δύναμις, ταύτῃ δʼ ἐκείνη οὐκ ἀεί· ἀνάγκη γὰρ τὸν εὖ ποιοῦντα καὶ ποιεῖν, τὸν δὲ μόνον ποιοῦντα οὐκ ἀνάγκη καὶ εὖ ποιεῖν.
And it is also clear that to the potentiality of doing a thing well there follows the potentiality of merely doing or being acted upon, but the latter is not always followed by the former; for it is necessary that he who does a thing well should also do it, but it is not necessary that he who merely does it should also do it well.