The true sign of intelligence is not knowledge but imagination.

It is difficult even to attach a precise meaning to the term "scientific truth." So different is the meaning of the word "truth" according to whether we are dealing with a fact of experience, a mathematical proposition or a scientific theory. "Religious truth" conveys nothing clear to me at all.

The road to perdition has ever been accompanied by lip service to an ideal.

Only morality in our actions can give beauty and dignity to life.

Everything has changed except the way man thinks (when the hydrogen bomb was exploded)

Since that deluge of newspaper articles I have been so flooded with questions, invitations, suggestions, that I keep dreaming I am roasting in Hell, and the mailman is the devil eternally yelling at me, showering me with more bundles of letters at my head because I have not answered the old ones.

I must seem like an ostrich who forever burries its head in the relativistic sands in order not to face the evil quanta.