Chapter 39

Substance is a thing which subsists in itself and has no need of another for its existence. And again: substance is everything that subsists in itself and does not have its existence in another—that is to say, that which is not because of any other thing, nor has its existence in another, nor has need of another to subsist, but which is in itself and is that in which the accident has its existence. Thus, color was made because of the body, that it might color it, but the body was not made because of the color. And the color exists in the body, not the body in color. For this reason the color is said to belong to the body and the body not to belong to the color. Thus, for example, although the color may often be changed and altered, yet the substance, that is to say, the body, is not changed but remains the same. Now 'substance' is so called from its 'being' (in the proper sense. On the other hand 'accident' is so called from its 'happening', and sometimes being and sometimes not being, because it is possible for the same accident to exist in the same thing or not to exist, and not only that, but for its contrary to exist there).

[25] {Περὶ οὐσίας.} Οὐσία ἐστὶ πρᾶγμα αὐθύπαρκτον μὴ δεόμενον ἑτέρου πρὸς σύστασιν: καὶ πάλιν οὐσία ἐστὶ πᾶν, ὅτιπερ αὐθυπόστατόν ἐστι καὶ μὴ ἐν ἑτέρῳ ἔχει τὸ εἶναι ἤγουν τὸ μὴ δι' ἄλλο ὂν μηδὲ ἐν ἑτέρῳ ἔχον τὴν ὕπαρξιν μηδὲ δεόμενον ἑτέρου πρὸς σύστασιν, ἀλλ' ἐν αὑτῷ ὄν, ἐν ᾧ καὶ τὸ συμβεβηκὸς ἔχει τὴν ὕπαρξιν: τὸ γὰρ χρῶμα διὰ τὸ σῶμα γέγονεν, ἵνα χρῴζῃ αὐτό, καὶ οὐ τὸ σῶμα διὰ τὸ χρῶμα. Καὶ τὸ χρῶμα ἐν τῷ σώματι ὑπάρχει καὶ οὐ τὸ σῶμα ἐν τῷ χρώματι: ὅθεν καὶ τὸ χρῶμα τοῦ σώματος λέγεται καὶ οὐ τὸ σῶμα τοῦ χρώματος. Πολλάκις τοιγαροῦν ἀλλασσομένου τοῦ χρώματος καὶ μεταβαλλομένου ἡ οὐσία οὐ μεταβάλλεται ἤγουν τὸ σῶμα, ἀλλὰ μένει τὸ αὐτό. Λέγεται δὲ οὐσία παρὰ τὸ εἶναι.