And whenever anyone informs us that he has found a man who knows all the arts, and all things else that anybody knows, and every single thing with a higher degree of accuracy than any other man –whoever tells us this, I think that we can only imagine him to be a simple creature who is likely to have been deceived by some wizard or actor whom he met, and whom he thought all-knowing, because he himself was unable to analyze the nature of knowledge and ignorance and imitation.

The Republic