The best way to prove the clearness of our mind, is by showing its faults; as when a stream discovers the dirt at the bottom, it convinces us of the transparency and purity of the water.
SOCRATES: Perhaps we may be wrong; if so, you in your wisdom should convince us that we are mistaken in preferring justice to injustice. THRASYMACHUS: And how am I to convince you, he said, if you are not already convinced by what I have just said; what more can I do for you? Would you have me put the proof bodily into your souls?