[Max Planck] was one of the finest people I have ever known... but he really didn't understand physics, [because] during the eclipse of 1919 he stayed up all night to see if it would confirm the bending of light by the gravitational field. If he had really understood [general relativity], he would have gone to bed the way I did

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.

I am convinced there is only one way to eliminate these grave evils, namely through the establishment of a socialist economy, accompanied by an educational system which would be oriented toward social goals.

Combinatory play seems to be the essential feature in productive thought.

Know where to find the information and how to use it - That's the secret of success.

The most important question a person can ask is, "Is the Universe a friendly place?

It is difficult to say what truth is, but sometimes it is so easy to recognize a falsehood.