What is the first business of one who practices philosophy? To get rid of self-conceit. For it is impossible for anyone to begin to learn that which he thinks he already knows.
Τί πρῶτόν ἐστιν ἔργον τοῦ φιλοσοφοῦντος; ἀποβαλεῖν οἴησιν· ἀμήχανον γάρ, ἅ τις εἰδέναι οἴεται, ταῦτα ἄρξασθαι μανθανειν.
Original text (Ancient Greek)