Peace cannot be kept by force; it can only be achieved by understanding.

Thinking like we (always) have is what got us where we are. It is not going to get us where we are going.

Nature hides her secrets because of her essential loftiness, but not by means of ruse.

War cannot be humanized. It can only be abolished.

Why do people speak of great men in terms of nationality? Great Germans, great Englishmen? Goethe always protested against being called a German poet. Great men are simply men and are not to be considered from the point of view of nationality, nor should the environment in which they were brought up be taken into account.

Intelligent life on other planets? I'm not even sure there is on earth!

But there is another reason for the high repute of mathematics: it is mathematics that offers the exact natural sciences a certain measure of security which, without mathematics, they could not attain.