Aristotle: De Interpretatione (On Interpretation)

εἶναι· καὶ γὰρ τούτου ἀπόφασις τὸ μὴ ἐνδεχόμενον εἶναι. Καὶ ἐπὶ τῶν ἄλλων δὲ ὁμοιοτρόπως, οἷον ἀναγκαίου τε καὶ ἀδυνάτου. Γίνεται γὰρ ὥσπερ ἐπ᾿ ἐκείνων τὸ εἶναι καὶ τὸ μὴ εἶναι προσθέσεις, τὰ δ᾿ ὑποκείμενα πράγματα τὸ μὲν λευκὸν τὸ δ᾿ ἄνθρωπος; οὕτως ἐνταῦθα τὸ μὲν εἶναι καὶ μὴ εἶναι ὡς ὑποκείμενον γίνεται, τὸ δὲ δύνασθαι καὶ τὸ ἐνδέχεσθαι προσθέσεις διορίζουσαι, ὥσπερ ἐπ᾿ ἐκείνων τὸ εἶναι καὶ μὴ εἶναι, τὸ ἀληθὲς καὶ τὸ ψεῦδος, ὁμοίως αὗται ἐπὶ τοῦ εἶναι δυνατὸν καὶ εἶναι οὐ δυνατόν. Τοῦ δὲ δυνατὸν μὴ εἶναι ἀπόφασις οὐ τὸ οὐ δυνατὸν εἶναι, ἀλλὰ τὸ οὐ δυνατὸν μὴ εἶναι, καὶ τοῦ δυνατὸν εἶναι οὐ τὸ δυνατὸν μὴ εἶναι, ἀλλὰ τὸ μὴ δυνατὸν εἶναι. Διὸ καὶ ἀκολουθεῖν ἂν δόξειαν ἀλλήλαις αἱ τοῦ δυνατὸν εἶναι καὶ δυνατὸν μὴ εἶναι· τὸ γὰρ αὐτὸ δυνατὸν εἶναι καὶ μὴ εἶναι· οὐ γὰρ ἀντιφάσεις ἀλλήλων αἱ τοιαῦται, τὸ δυνατὸν εἶναι καὶ δυνατὸν μὴ εἶναι. Ἀλλὰ τὸ δυνατὸν εἶναι καὶ μὴ δυνατὸν εἶναι οὐδέποτε ἐπὶ τοῦ αὐτοῦ ἅμα ἀληθεύονται· ἀντίκεινται γάρ. Οὐδέ γε τὸ δυνατὸν μὴ εἶναι καὶ οὐ δυνατὸν μὴ εἶναι οὐδέποτε ἅμα ἐπὶ τοῦ αὐτοῦ ἀληθεύονται. Ὁμοίως δὲ καὶ τοῦ ἀναγκαῖον εἶναι ἀπόφασις οὐ τὸ ἀναγκαῖον μὴ εἶναι, ἀλλὰ τὸ μὴ ἀναγκαῖον εἶναι· τοῦ δὲ ἀναγκαῖον μὴ εἶναι τὸ μὴ ἀναγκαῖον μὴ εἶναι. Καὶ τοῦ ἀδύνατον εἶναι οὐ τὸ ἀδύνατον μὴ εἶναι, ἀλλὰ τὸ μὴ ἀδύνατον εἶναι· τοῦ δὲ ἀδύνατον μὴ εἶναι τὸ οὐκ ἀδύνατον μὴ εἶναι. Καὶ καθόλου δέ, ὥσπερ εἴρηται, τὸ μὲν εἶναι καὶ μὴ εἶναι δεῖ τιθέναι ὡς τὰ ὑποκείμενα, κατάφασιν δὲ καὶ ἀπόφασιν ταῦτα ποιοῦντα πρὸς τὸ εἶναι καὶ μὴ εἶναι. συντάττειν. Καὶ ταύτας οἴεσθαι χρὴ εἶναι τὰς ἀντικειμένας φάσεις, δυνατόν — οὐ δυνατόν, ἐνδεχόμενον — οὐκ ἀνδεχόμενον, ἀδύνατον — οὐκ ἀδύνατον, ἀναγκαῖον — οὐκ ἀναγκαῖον, ἀληθές — οὐκ ἀληθές.

Καὶ αἱ ἀκολουθήσεις δὲ κατὰ λόγον γίνονται οὕτω τιθεμένοις·