God does not care about our mathematical difficulties. He integrates empirically.

Certainly there are things worth believing. I believe in the brotherhood of man and the uniqueness of the individual. But if you ask me to prove what I believe, I can't. You know them to be true but you could spend a whole lifetime without being able to prove them. The mind can proceed only so far upon what it knows and can prove. There comes a point where the mind takes a leap—call it intuition or what you will—and comes out upon a higher plane of knowledge, but can never prove how it got there. All great discoveries have involved such a leap.

Whoever is careless with the truth in small matters cannot be trusted in important affairs.

A successful man is he who receives a great deal from his fellow men, usually incomparably more than corresponds to his service to them. The value of a man, however, should be seen in what he gives and not in what he is able to receive.

Everybody acts not only under external compulsion but also in accordance with inner necessity.

Stupidity is a personal achievement which transcends national boundaries.

Non-cooperation in military matters should be an essential moral principle for all true scientists.