Whatever your problems in math are, I assure mine are greater.

Non-cooperation in military matters should be an essential moral principle for all true scientists.

In art, and in the higher ranges of science, there is a feeling of harmony which underlies all endeavor. There is no true greatness in art or science without that sense of harmony.

Every day, man is making bigger and better fool-proof things, and every day, nature is making bigger and better fools. So far, I think nature is winning.

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.

The world we have created is a product of our thinking; it cannot be changed without changing our thinking. If we want to change the world we have to change our thinking...no problem can be solved from the same consciousness that created it. We must learn to see the world anew.

Berlin is the place to which I am most closely bound by human and scientific ties.