Plato, Meno 71c

οὐδʼ ὅτι ἀρετή ἐστιν οἶσθα, ἀλλὰ ταῦτα περὶ σοῦ καὶ οἴκαδε ἀπαγγέλλωμεν; μὴ μόνον γε, ὦ ἑταῖρε, ἀλλὰ καὶ ὅτι οὐδʼ ἄλλῳ πω ἐνέτυχον εἰδότι, ὡς ἐμοὶ δοκῶ. τί δέ; Γοργίᾳ οὐκ ἐνέτυχες ὅτε ἐνθάδε ἦν; ἔγωγε. εἶτα οὐκ ἐδόκει σοι εἰδέναι; οὐ πάνυ εἰμὶ μνήμων, ὦ Μένων, ὥστε οὐκ ἔχω εἰπεῖν ἐν τῷ παρόντι πῶς μοι τότε ἔδοξεν. ἀλλʼ ἴσως ἐκεῖνός τε οἶδε, καὶ σὺ ἃ ἐκεῖνος ἔλεγε· ἀνάμνησον οὖν

that you do not even know what virtue is? Are we to return home with this report of you? Not only this, my friend, but also that I never yet came across anybody who did know, in my opinion. What? You did not meet Gorgias when he was here? I did. And you didn’t consider that he knew? I have not a very good memory, Meno, so I cannot tell at the moment how he struck me then. It may be that he did know, and that you know what he said: