It is impossible to get anywhere without sinning against reason.

When the nazis came to power, I looked to the universities that prided themselves upon their intellectual freedom, and they failed me. I looked to the German press, which prided itself on the freedom of the press, and it failed me. Until at last the churches stood alone, and that for which I once had little regard earned my respect.

No scientist thinks in formulae.

It is difficult even to attach a precise meaning to the term "scientific truth." So different is the meaning of the word "truth" according to whether we are dealing with a fact of experience, a mathematical proposition or a scientific theory. "Religious truth" conveys nothing clear to me at all.

Man like every other animal is by nature indolent. If nothing spurs him on, then he will hardly think, and will behave from habit like an automaton.

Assumptions are made and most assumptions are wrong.

It may affront the military-minded person to suggest a regime that does not maintain any military secrets.