Book 1, Chapter 11

καὶ ἐπεὶ τὸ κατὰ φύσιν ἡδύ, τὰ συγγενῆ δὲ κατὰ φύσιν ἀλλήλοις ἐστίν, πάντα τὰ συγγενῆ καὶ ὅμοια ἡδέα ὡς ἐπὶ τὸ πολύ, οἷον ἄνθρωπος ἀνθρώπῳ καὶ ἵππος ἵππῳ καὶ νέος νέῳ, ὅθεν καὶ αἱ παροιμίαι εἴρηνται, ἧλιξ ἥλικα τέρπει, καὶ ὡς αἰεὶ τὸν ὁμοῖον, καὶ ἔγνω δὲ θὴρ θῆρα, καὶ γὰρ κολοιὸς παρὰ κολοιόν, καὶ ὅσα ἄλλα τοιαῦτα.