We must dedicate our lives to drying up the source of war: ammunition factories.

God does not play dice.

Real sign of intelligence isn't knoweldge, it's imagination

I do not believe that a moral philosophy can ever be founded on a scientific basis. … The valuation of life and all its nobler expressions can only come out of the soul’s yearning toward its own destiny. Every attempt to reduce ethics to scientific formulas must fail. Of that I am perfectly convinced.

Every reminiscence is colored by the way things are today, and therefore by a delusive point of view.

Men marry women with the hope they will never change. Women marry men with the hope they will change. Invariably they are both disappointed.

[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.