What a man knows is everywhere at war with what he wants.

Whenever man forgets that man is an animal, the result is always to make him less humane.

Not to have known - as most men have not - either the mountain or the desert is not to have known one's self. Not to have known one's self is to have known no one.

The cockroach and the bird were both here long before we were. Both could.

A tragic writer does not have to believe in God, but he must believe in man.

Though many have tried, no one has ever yet explained away the decisive fact that science, which can do so much, cannot decide what it ought to do.

There is no conceivable human action which custom has not at one time justified and at another condemned.