Solitude is painful when one is young, but delightful when one is more mature.

You have to learn the rules of the game. And then you have to play better than anyone else.

You imagine that I look back on my life's work with calm satisfaction. But from nearby it looks quite different. There is not a single concept of which I am convinced that it will stand firm, and I feel uncertain whether I am in general on the right track.

Opinions about obviousness are to a certain extent a function of time.

Out yonder there is this huge world, which exists independently of us human beings and which stands before us like a great, eternal riddle, at least partially accessible to our inspection and thinking

If I had only one hour to save the world, I would spend fifty-five minutes defining the problem, and only five minutes finding the solution.

Children don’t heed the life experiences of their parents, and nations ignore history. Bad lessons always have to be learned anew.