It is a very high goal which, with our weak powers, we can reach only very inadequately, but which gives a sure foundation to our aspirations and valuations.

[Kepler] had to realize clearly that logical-mathematical theoretizing, no matter how lucid, could not guarantee truth by itself; that the most beautiful logical theory means nothing in natural science without comparison with the exactest experience. Without this philosophic attitude, his work would not have been possible.

I refuse to engage in an intellectual battle with an unarmed man.

Student: Dr. Einstein, Aren't these the same questions as last year's [physics] final exam? Dr. Einstein: Yes; But this year the answers are different.

Mankind must give up war in the Atomic Era. What is at stake is the life or death of humanity.

Although I am a typical loner in my daily life, my awareness of belonging to the invisible community of those who strive for truth, beauty, and justice has prevented me from feelings of isolation.

Chess holds its master in its own bonds, shackling the mind and brain so that the inner freedom of the very strongest must suffer.