Laws alone can not secure freedom of expression; in order that every man present his views without penalty there must be spirit of tolerance in the entire population.

Qualities I sought in a scientific theory were naturalness, inner perfection and logical simplicity from an aesthetic approach.

Those who have an interest in keeping the machinery of war going will stop at nothing to make public opinion subservient to their murderous ends.

The physicists say that I am a mathematician, and the mathematicians say that I am a physicist. I am a completely isolated man and though everybody knows me, there are very few people who really know me.

If you've never failed, you've never tried anything new.

I believe that pipe smoking contributes to a somewhat calm and objective judgement in all human affairs.

Failing isn't bad when you learn what not to do.