One has to know the size of one's stomach.

The ancient precept, “Know thyself,” and the modern precept, “Study nature,” become at last one maxim.

Faith: not wanting to know what is true.

No one is free who has not obtained the empire of himself. No man is free who cannot command himself.

Know thyself? If I knew myself I would run away.

When one has finished building one's house, one suddenly realizes that in the process one has learned something that one really needed to know in the worst way - before one began.