We must be prepared to make the same heroic sacrifices for the cause of peace that we make ungrudgingly for the cause of war.

The great moral teachers of humanity were in a way artistic geniuses in the art of living.

There are few enough people with sufficient independence to see the weaknesses and follies of their contemporaries and remain themselves untouched by them.

Arrows of hate have been aimed at me too, but they have never hit me, because somehow they belonged to another world with which I have no connection whatsoever.

Assumptions are made and most assumptions are wrong.

I wouldn't want to live if I did not have my work. In any case, it's good that I'm already old and personally don't have to count on a prolonged future.

The scientific theorist is not to be envied. For Nature, or more precisely experiment, is an exorable and not very friendly judge of his work. It never says "yes" to a theory. In the most favorable cases it says "Maybe," and in the great majority of cases simply "No." If an experiment agrees with a theory it means for the latter "Maybe," and if it does not agree it means "No." Probably every theory will some day experience its "No" - most theories, soon after conception.