The soul of him who has education is whole and perfect and escapes the worst disease, but, if a man's education be neglected, he walks lamely through… - Plato

Parmenides: Just as things in a picture, when viewed from a distance, appear to be all in one and the same condition and alike.

True opinions are a fine thing and do all sorts of good so long as they stay in their place; but they will not stay long. They run away from a man's mind, so they are not worth much until you tether them by working out the reason. Once they are tied down, they become knowledge, and are stable.

τοῖς μὲν οὖν τότε, ἅτε οὐκ οὖσι σοφοῖς ὥσπερ ὑμεῖς οἱ νέοι, ἀπέχρη δρυὸς καὶ πέτρας ἀκούειν ὑπ᾽ εὐηθείας, εἰ μόνον ἀληθῆ λέγοιεν: σοὶ δ᾽ ἴσως διαφέρει τίς ὁ λέγων καὶ ποδαπός.