If I had my life to live over again, I would elect to be a trader of goods rather than a student of science. I think barter is a noble thing.

Consider the concepts referred to in the words 'where', 'when', 'why', 'being', to the elucidation of which innumerable volumes of philosophy have been devoted. We fare no better in our speculations than a fish which should strive to become clear as to what is water.

Lasting harmony with a woman (was) an undertaking in which I twice failed rather disgracefully.

If I am right the Germans will say I was a German, and the French will say I was a Jew; If I am wrong the Germans will say I was a Jew and the French will say I was a German.

I have just got a new theory of eternity.

I never said half the crap people said I did.

Nothing happens til something moves.