Plato, Meno 71d

με πῶς ἔλεγεν. εἰ δὲ βούλει, αὐτὸς εἰπέ· δοκεῖ γὰρ δήπου σοὶ ἅπερ ἐκείνῳ. ἔμοιγε. ἐκεῖνον μὲν τοίνυν ἐῶμεν, ἐπειδὴ καὶ ἄπεστιν· σὺ δὲ αὐτός, ὦ πρὸς θεῶν, Μένων, τί φῂς ἀρετὴν εἶναι; εἶπον καὶ μὴ φθονήσῃς, ἵνα εὐτυχέστατον ψεῦσμα ἐψευσμένος ὦ, ἂν φανῇς σὺ μὲν εἰδὼς καὶ Γοργίας, ἐγὼ δὲ εἰρηκὼς μηδενὶ πώποτε εἰδότι ἐντετυχηκέναι.

remind me therefore how he expressed it; or if you like, make your own statement, for I expect you share his views. I do. Then let us pass him over, since in fact he is not present, and do you tell me, in heaven’s name, what is your own account of virtue. Speak out frankly, that I may find myself the victim of a most fortunate falsehood, if you and Gorgias prove to have knowledge of it, while I have said that I never yet came across anyone who had.