Plato, Laws 668a

ἀληθεῖ—καὶ δὴ καὶ πᾶσαν ἰσότητα· οὐ γὰρ εἴ τῳ δοκεῖ ἢ μή τις χαίρει τῳ, τό γε ἴσον ἴσον οὐδὲ τὸ σύμμετρον ἂν εἴη σύμμετρον ὅλως—ἀλλὰ τῷ ἀληθεῖ πάντων μάλιστα, ἥκιστα δὲ ὁτῳοῦν ἄλλῳ; παντάπασι μὲν οὖν. οὐκοῦν μουσικήν γε πᾶσάν φαμεν εἰκαστικήν τε εἶναι καὶ μιμητικήν; τί μήν; ἥκιστʼ ἄρα ὅταν τις μουσικὴν ἡδονῇ φῇ κρίνεσθαι, τοῦτον ἀποδεκτέον τὸν λόγον, καὶ ζητητέον ἥκιστα ταύτην

or of untrue opinion, nor indeed should any kind of equality be so judged? The reason why the equal is equal, or the symmetrical symmetrical, is not at all because a man so opines, or is charmed thereby, but most of all because of truth, and least of all for any other reason. Most certainly. We assert, do we not, that all music is representative and imitative? Of course. So whenever a man states that pleasure is the criterion of music, we shall decisively reject his statement; and we shall regard such music as the least important of all (if indeed any music