Physics is essentially an intuitive and concrete science. Mathematics is only a means for expressing the laws that govern phenomena.

In living through this great epoch, it is difficult to reconcile oneself to the fact that one belongs to that mad, degenerate species that boasts of its free will. How I wish that somewhere there existed an island for those who are wise and of good will. In such a place even I should be an ardent patriot!

Don't second guess the mistakes you've made, others will do that for you. Make things as simple as possible, but not simpler.

One lives one's life under constant tension, until it's time to go for good

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.

If you're not sure why you're doing something, you can never do enough of it. Imagination is more important than knowledge.

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