Since then we see that of which we are speaking to be warm and operative, we thereby draw the further inference that it is not inanimate; but as, in respect of its corporeal part, we do not say that it is flesh, and bones, and hair, and all that we observe in the human being, but that potentially it is each of these things, yet does not visibly appear to be so; so also of the part which belongs to the soul, the elements of rationality, and desire, and anger, and all the powers of the soul are not yet visible; yet we assert that they have their place in it, and that the energies of the soul also grow with the subject in a manner similar to the formation and perfection of the body.

For just as a man when perfectly developed has a specially marked activity of the soul, so at the beginning of his existence he shows in himself that co-operation of the soul which is suitable and conformable to his existing need, in its preparing for itself its proper dwelling-place by means of the implanted matter; for we do not suppose it possible that the soul is adapted to a strange building, just as it is not possible that the seal impressed on wax should be fitted to an engraving that does not agree with it.

For as the body proceeds from a very small original to the perfect state, so also the operation of the soul, growing in correspondence with the subject, gains and increases with it. For at its first formation there comes first of all its power of growth and nutriment alone, as though it were some root buried in the ground; for the limited nature of the recipient does not admit of more; then, as the plant comes forth to the light and shows its shoot to the sun, the gift of sensibility blossoms in addition, but when at last it is ripened and has grown up to its proper height, the power of reason begins to shine forth like a fruit, not appearing in its whole vigour all at once, but by care increasing with the perfection of the instrument, bearing always as much fruit as the powers of the subject allow.

Ἐπειδὴ τοίνυν ἔνθερμόν τε καὶ ἐνεργὸν θεωροῦμεν τοῦτο͵ περὶ οὗ τὸν λόγον ποιούμεθα͵ τὸ μηδὲ ἄψυχον εἶναι διὰ τούτων συντεκμαιρόμεθα. Ἀλλ' ὥσπερ κατὰ τὸ σωματικὸν αὐτοῦ μέρος οὐ σάρκα φαμὲν αὐτὸ καὶ ὀστέα καὶ τρίχας καὶ ὅσα περὶ τὸ ἀνθρώπινον καθορᾶται͵ ἀλλὰ τῇ δυνάμει μὲν τούτων ἕκαστον εἶναι͵ οὔπω δὲ κατὰ τὸ ὁρώμενον φαίνεσθαι, οὕτω καὶ ἐπὶ τοῦ ψυχικοῦ μέρους οὔπω μὲν τὸ λογικὸν καὶ ἐπιθυμητικὸν καὶ θυμοειδὲς καὶ ὅσα περὶ ψυχὴν καθορᾶται͵ καὶ ἐν ἐκείνῳ χώραν ἔχειν φαμέν͵ ἀναλόγως δὲ τῆς τοῦ σώματος κατασκευῆς τε καὶ τελειώσεως͵ καὶ τὰς τῆς ψυχῆς ἐνεργείας τῷ ὑποκειμένῳ συναύξεσθαι.  

Ὥσπερ γὰρ τελειωθεὶς ὁ ἄνθρωπος ἐν τοῖς μείζοσιν ἔχει διαφαινομένην τῆς ψυχῆς τὴν ἐνέργειαν, οὕτως ἐν ἀρχῇ τῆς συστάσεως τὴν κατάλληλόν τε καὶ σύμμετρον τῇ παρούσῃ χρείᾳ συνέργειαν τῆς ψυχῆς ἐφ' ἑαυτοῦ διαδείκνυσιν͵ ἐν τῷ κατασκευάζειν αὐτὴν ἑαυτῇ διὰ τῆς ἐντεθείσης ὕλης τὸ προσφυὲς οἰκητήριον. Οὐδὲ γὰρ εἶναι δυνατὸν λογιζόμεθα͵ ἀλλοτρίαις οἰκοδομαῖς τὴν ψυχὴν ἐναρμόζεσθαι͵ ὡς οὐκ ἔστι τὴν ἐν τῷ κηρῷ σφραγίδα πρὸς ἀλλοτρίαν ἁρμοσθῆναι γλυφήν.

Καθάπερ γὰρ τὸ σῶμα ἐκ βραχυτάτου πρὸς τὸ τέλειον πρόεισιν͵ οὕτω καὶ ἡ τῆς ψυχῆς ἐνέργεια καταλλήλως ἐμφυομένη τῷ ὑποκειμένῳ͵ συνεπιδίδωσι καὶ συναύξεται. Προηγεῖται μὲν γὰρ αὐτῆς ἐν τῇ πρώτῃ κατασκευῇ οἶον ῥίζης τινὸς ἐν τῇ γῇ κατακρυφθείσης ἡ αὐξητική τε καὶ θρεπτικὴ δύναμις μόνη. Οὐ γὰρ χωρεῖ τὸ περισσότερον ἡ τοῦ δεχομένου βραχύτης. Εἶτα προελθόντος εἰς φῶς τοῦ φυτοῦ καὶ ἡλίῳ τὴν βλάστην δείξαντος͵ ἡ αἰσθητικὴ χάρις ἐπήνθησεν. Ἁδρυνθέντος δὲ ἤδη καὶ εἰς σύμμετρον μῆκος ἀναδραμόντος͵ καθάπερ τις καρπὸς διαλάμπειν ἡ λογικὴ δύναμις ἄρχεται͵ οὐ πᾶσα ἀθρόως ἐκφαινομένη, ἀλλὰ τῇ τοῦ ὀργάνου τελειώσει δι' ἐπιμελείας συναύξουσα͵ τοσοῦτον ἀεὶ καρποφοροῦσα͵ ὅσον χωρεῖ τοῦ ὑποκειμένου ἡ δύναμις.