Those who are not shocked when they first come across quantum theory cannot possibly have understood it.

Never express yourself more clearly than you are able to think.

When searching for harmony in life one must never forget that in the drama of existence we are ourselves both actors and spectators.

There are trivial truths and the great truths. The opposite of a trivial truth is plainly false. The opposite of a great truth is also true.

What is that we human beings ultimately depend on? We depend on our words. We are suspended in language. Our task is to communicate experience and ideas to others.

Of course I don't believe in it [pointing to horseshoe on his office wall]. But I understand that it brings you luck whether you believe in it or not.

If you have a correct statement, then the opposite of a correct statement is of course an incorrect statement, a wrong statement. But when you have a deep truth, then the opposite of a deep truth may again be a deep truth.