I know that I am intelligent, because I know that I know nothing.

Fellow citizens, why do you burn and scrape every stone to gather wealth and take so little care of your children to whom you must one day relinquish all?

No citizen has any right to be an amateur in the matter of physical training; it is part of his profession as a citizen to keep himself in good condition... [It is] a disgrace for a man to grow old without seeing the beauty and the strength of which his body is capable.

The misuse of language induces evil in the soul.

I alone know I am wise because I alone know I know nothing.

No one can teach, if by teaching we mean the transmission of knowledge, in any mechanical fashion, from one person to another. The most that can be done is that one person who is more knowledgeable than another can, by asking a series of questions, stimulate the other to think, and so cause him to learn for himself.

A system of morality that is based on relative emotional values is a mere illusion, a thoroughly vulgar conception that has nothing sound in it and nothing true.