A theory is scientific only if it can be disproved. But the moment you try to cover absolutely everything the chances are that you cover nothing.

... an opportunity to allow the bees in one's bonnet to buzz even more noisily than usual.

[Newton's calculations] entered the marrow of what we know without knowing how we know it.

Religion divides us, while it is our human characteristics that bind us to each other.

Our humanist attitude should therefore throughout be to stress what we all have in common with each other and relegate quarrelsome religion to the private domain where it can do [less] harm.

The landscape has been so totally changed, the ways of thinking have been so deeply affected, that it is very hard to get hold of what it was like before… It is very hard to realize how total a change in outlook Isaac Newton has produced.

What I remember most clearly was that when I put down a suggestion that seemed to me cogent and reasonable, Einstein did not in the least contest this, but he only said, 'Oh, how ugly.' As soon as an equation seemed to him to be ugly, he really rather lost interest in it and could not understand why somebody else was willing to spend much time on it. He was quite convinced that beauty was a guiding principle in the search for important results in theoretical physics.