Where I cannot be moral, my power is gone.

One needs only to get old to become milder; I don't see anyone make a mistake I hadn't also made.

The world only goes forward because of those who oppose it.

Mankind? That is an abstraction. There have always been and always will be only individuals.

The connoisseur of art must be able to appreciate what is simply beautiful, but the common run of people is satisfied with ornament.

The close and thoughtful observer more and more learns to recognize his limitations. He realizes that with the steady growth of knowledge more and more new problems keep on emerging.

Truth is a torch, but a terrific one; therefore we all try to reach it with closed eyes, lest we should be scorched.