1011 b 25 καθ᾿ ἑνὸς ὁτιοῦν. δῆλον δὲ πρῶτον μὲν ὁρι- σαμένοις τί τὸ ἀληθὲς καὶ ψεῦδος. τὸ μὲν γὰρ λέγειν τὸ ὂν μὴ εἶναι ἢ τὸ μὴ ὂν εἶναι ψεῦδος, τὸ δὲ τὸ ὂν εἶναι καὶ τὸ μὴ ὂν μὴ εἶναι ἀληθές, ὥστε καὶ ὁ λέγων εἶναι ἢ μὴ ἀληθεύσει ἢ ψεύσεται. ἀλλ᾿ οὔτε τὸ ὂν λέγεται μὴ εἶναι ἢ εἶναι οὔτε τὸ 30 μὴ ὄν. ἔτι ἤτοι1 μεταξὺ ἔσται τῆς ἀντιφάσεως ὥσπερ τὸ φαιὸν μέλανος καὶ λευκοῦ, ἢ ὡς τὸ μηδέτερον ἀνθρώπου καὶ ἵππου. εἰ μὲν οὖν οὕτως, οὐκ ἂν μεταβάλλοι (ἐκ μὴ ἀγαθοῦ γὰρ εἰς ἀγαθὸν μεταβάλλει, ἢ ἐκ τούτου εἰς μὴ ἀγαθόν)· νῦν δ᾿ ἀεὶ φαίνεται. οὐ γὰρ ἔστι μεταβολὴ ἀλλ᾿ 35 ἢ εἰς τὰ ἀντικείμενα καὶ μεταξύ. εἰ δ᾿ ἔστι 1012 aμεταξύ, καὶ οὕτως εἴη ἄν τις εἰς λευκὸν οὐκ ἐκ μὴ λευκοῦ γένεσις· νῦν δ᾿ οὐχ ὁρᾶται. ἔτι πᾶν τὸ διανοητὸν καὶ νοητὸν ἡ διάνοια ἢ κατάφησιν ἢ ἀπόφησιν—τοῦτο δ᾿ ἐξ ὁρισμοῦ δῆλον—ὅταν ἀληθεύῃ ἢ ψεύδηται· ὅταν μὲν ὡδὶ συνθῇ φᾶσα ἢ 5 ἀποφᾶσα, ἀληθεύει, ὅταν δὲ ὡδί, ψεύδεται. Ἔτι παρὰ πάσας δεῖ εἶναι τὰς ἀντιφάσεις, εἰ μὴ λόγου ἕνεκα λέγεται· ὥστε καὶ οὔτε ἀληθεύσει τις οὔτ᾿ οὐκ ἀληθεύσει· καὶ παρὰ τὸ ὂν καὶ τὸ μὴ ὂν ἔσται, ὥστε καὶ παρὰ γένεσιν καὶ φθορὰν μεταβολή τις ἔσται. Ἔτι ἐν ὅσοις γένεσιν ἡ ἀπόφασις 10 τὸ ἐναντίον ἐπιφέρει, καὶ ἐν τούτοις ἔσται, οἷον
must either assert or deny one thing, whatever it excluded middle. may be. This will be plain if we first define truth and falsehood. To say that what is is not, or that what is not is, is false; but to say that what is is, and what is not is not, is true; and therefore also he who says that a thing is or is not will say either what is true or what is false. But neither what is nor2 what is not is said not to be or to be. Further, an intermediate between contraries will be intermediate either as grey is between black and white, or as “neither man nor horse” is between man and horse. If in the latter sense, it cannot change (for change is from not-good to good, or from good to not-good); but in fact it is clearly always changing; for change3 can only be into the opposite and the intermediate. And if it is a true intermediate, in this case too there would be a kind of change into white not from not-white; but in fact this is not seen.a Further, the understanding either affirms or denies every object of understanding or thought (as is clear from the definitionb) whenever it is right or wrong. When, in4 asserting or denying, it combines the predicates in one way, it is right; when in the other, it is wrong.
Again, unless it is maintained merely for argument’s sake, the intermediate must exist beside all contrary terms; so that one will say what is neither true nor false. And it will exist beside what is and what is not; so that there will be a form of change beside generation and destruction.
Again, there will also be an intermediate in all5 classes in which the negation of a term implies the contrary assertion; e.g., among numbers there will