If a man has lost a leg or an eye, he knows he has lost a leg or an eye; but if he has lost a self - himself - he cannot know it, because he is no longer there to know it.

The greatness of man is great in that he knows himself to be wretched. A tree does not know itself to be wretched.

The fool doth think he is wise, but the wise man knows himself a fool.

Man can embody truth but he cannot know it.

He who knows himself is enlightened.

In general, people are afraid to acknowledge hallucinations because they immediately see them as a sign of something awful happening to the brain, whereas in most cases they're not.