ΙΣΤΟΡΙΩΝ Ζ, Κεφ. α′. ΖΗΝΩΝ

Τὸ δʼ ἠθικὸν μέρος τῆς φιλοσοφίας διαιροῦσιν εἴς τε τὸν περὶ ὁρμῆς καὶ εἰς τὸν περὶ ἀγαθῶν καὶ κακῶν τόπον καὶ εἰς τὸν περὶ παθῶν καὶ περὶ ἀρετῆς καὶ περὶ τέλους περί τε τῆς πρώτης ἀξίας καὶ τῶν πράξεων καὶ περὶ τῶν καθηκόντων προτροπῶν τε καὶ ἀποτροπῶν. [καὶ] οὕτω δʼ ὑποδιαιροῦσιν οἱ περὶ Χρύσιππον καὶ Ἀρχέδημον καὶ Ζήνωνα τὸν Ταρσέα καὶ Ἀπολλόδωρον καὶ Διογένην καὶ Ἀντίπατρον καὶ Ποσειδώνιον· ὁ μὲν γὰρ Κιτιεὺς Ζήνων καὶ ὁ Κλεάνθης, ὡς ἂν ἀρχαιότεροι, ἀφελέστερον περὶ τῶν πραγμάτων διέλαβον. οὗτοι δὲ διεῖλον καὶ τὸν λογικὸν καὶ τὸν φυσικόν.