Proof is an idol before which the mathematician tortures himself.

Unless the structure of the nucleus has a surprise in store for us, the conclusion seems plain — there is nothing in the whole system of laws of physics that cannot be deduced unambiguously from epistemological considerations.

Asked in 1919 whether it was true that only three people in the world understood the theory of general relativity, [Eddington] allegedly replied: "Who's the third?"

The word reality frightens me.

Whatever else there may be in our nature, responsibility toward truth is one of its attributes.

The mathematics is not there till we put it there.

Who will observe the observers?