Every sentence I utter must be understood not as an affirmation, but as a question.

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

Nothing exists until it is measured.

Everything we call real is made of things that cannot be regarded as real.

Sometimes the child in one behaves a certain way and the rest of oneself follows behind, slowly shaking its head.

A physicist visits a colleague and notices a horseshoe hanging on the wall above the entrance. 'Do you really believe that a horseshoe brings luck?' he asks. 'No,' replies the colleague, 'but I've been told that it works even if you don't believe in it.'

If we couldn't laugh at ourselves, that would be the end of everything.