God and Satan alike are essentially human figures, the one a projection of ourselves, the other of our enemies.

Three passions, simple but overwhelmingly strong, have governed my life: the longing for love, the search for knowledge, and unbearable pity for the suffering of mankind.

Love is a slippery eel that bites like hell

What has human happiness to do with morals? The object of morals is not to make people happy.

One of the symptoms of approaching nervous breakdown is the belief that one's work is terribly important, and that to take a holiday would bring all kinds of disaster. If I were a medical man, I should prescribe a holiday to any patient who considered his or her work important.

The good life is one inspired by love and guided by knowledge.

Broadly speaking, we are in the middle of a race between human skill as a means and human folly as an end.