In the midst of every crisis, lies great opportunity.

No one must think that Newton’s great creation can be overthrown in any real sense by this [Theory of Relativity] or by any other theory. His clear and wide ideas will for ever retain their significance as the foundation on which our modern conceptions of physics have been built.

When men are engaged in war and conquest, the tools of science become as dangerous as a razor in the hands of a child of three. We must not condemn man because his inventiveness and patient conquest of the forces of nature are being exploited for false and destructive purposes. Rather, we should remember that the fate of mankind hinges entirely upon man’s moral development.

Marvellous, what ideas the young people have these days. But I don't believe a word of it.

Coincidences are God's way of staying anonymous.

I came- though the child of entirely irreligious (Jewish) parents - to a deep religiousness, which, however, reached an abrupt end at the age of twelve.

An expert is a person who has few new ideas; a beginner is a person with many.