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

If anybody says he can think about quantum physics without getting giddy, that only shows he has not understood the first thing about them.

An expert is someone who knows some of the worst mistakes, which can be made, in a very narrow field.

An expert is a man who has made all the mistakes which can be made in a very narrow field.

Your theory is crazy, but it's not crazy enough to be true.

No, no, you're not thinking; you're just being logical.

If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet.

Prediction is very difficult, especially if it's about the future.

How wonderful that we have met with a paradox. Now we have some hope of making progress.