Β, Chapter 11

εἰσὶν δὲ καὶ αἱ φιλίαι αὗται, ἥ τε κατὰ τὸ ἀγαθὸν καὶ ἡ κατὰ τὸ ἡδὺ καὶ ἡ κατὰ τὸ συμφέρον, οὐχ αἱ αὐταὶ μέν, οὐ παντελῶς δὲ οὐδὲ ἀλλότριαι ἀλλήλων, ἀλλʼ ἀπὸ ταὐτοῦ πως ἠρτημέναι εἰσίν. οἷον φαμὲν ἰατρικὸν τὸ μαχαίριον, ἰατρικὸν τὸν ἄνθρωπον, καὶ ἰατρικὴν τὴν ἐπιστήμην· ταῦτα οὐχ ὁμοίως λέγονται, ἀλλὰ τὸ μὲν μαχαίριον τῷ χρήσιμον εἶναι πρὸς ἰατρικὴν ἰατρικὸν λέγεται, ὁ δʼ ἄνθρωπος τῷ ποιητικὸς εἶναι ὑγιείας, ἡ δʼ ἐπιστήμη τῷ αἰτία εἶναι καὶ ἀρχή.