ἑκόντα ἐξαμαρτάνειν: this also (cf. 345 b) is a peculiarly Socratic thought, founded upon the principle that all morality rests upon knowledge. Cf. 352 d, 358 e, Gorg. 509 e ἡνίκα ὡμολογήσαμεν μηδένα βουλόμενον ἀδικεῖν, ἀλλ᾽ ἄκοντας τοὺς ἀδικοῦντας πάντας ἀδικεῖν.
καὶ δὴ καί: after a general statement lays marked stress on the special case which follows it. Cf. 348 e, Apol. 18 a. See H. 1042 c.