This is...self-knowled ge-for a man to know what he knows, and what he does not know.
The understanding of mathematics is necessary for a sound grasp of ethics.
All I know is that I do not know anything
One cannot come closer to the gods than by bringing health to his Fellow Man.
What a lot of things there are a man can do without.
If what you want to tell me is neither True nor Good nor even Useful, why tell it to me at all