I don't know anything that gives me greater pleasure, or profit either, than talking or listening to philosophy. But when it comes to ordinary conversation, such as the stuff you talk about financiers and the money market, well, I find it pretty tiresome personally, and I feel sorry that my friends should think they're being very busy when they're really doing absolutely nothing. Of course, I know your idea of me: you think I'm just a poor unfortunate, and I shouldn't wonder if your right. But then I dont THINK that you're unfortunate - I know you are.
PlatoSOCRATES: 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?
Plato