A country cannot simultaneously prepare and prevent war. I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones. The distinctions separating the social classes are false; in the last analysis they rest on force.

A religious person is devout in the sense that he has no doubt about the significance of those superpersonal objects and goals which neither require nor are capable of rational foundation

I do not play games. There is not time for it. When I get through with work, I don't want anything that requires the working of the mind.

I'm not a genius. I'm just passionately curious.

The scientist finds his reward in what Henri Poincare calls the joy of comprehension, and not in the possibility of application to which any discovery may lead.

Never let yourself be seduced by any problem, no matter how difficult.

Perfection of means and confusion of goals seem to characterize our age. If we desire sincerely and passionately the safety, the welfare and the free development of the talents of all men, we shall not be in want of the means to approach such a state.