When I think of the most able students I have encountered in my teaching - I mean those who have distinguished themselves not only by skill but by independence of thought - then I must confess that all have had a lively interest in epistemology.

The Constitution only guarantees the American people the right to pursue happiness. You have to catch it yourself. A table, a chair, a bowl of fruit and a violin; what else does a man need to be happy?

Many of the things you can count, don't count. Many of the things you can't count, really count.

... on principle, it is quite wrong to try founding a theory on observable magnitudes alone. In reality the very opposite happens. It is the theory which decides what we can observe.

Mere praise of peace is easy and ineffective. What is needed is acitve participation in the fight against war and everything which leads to it.

I believe that Gandhi’s views were the most enlightened of all the political men in our time. We should strive to do things in his spirit: not to use violence in fighting for our cause, but by non-participation in anything you believe is evil.

A theory can be proved by experiment; but no path leads from experiment to the birth of a theory.