For the most part we humans live with the false impression of security and a feeling of being at home in a seemingly familiar and trustworthily physical and human environment. But when the expected course of everyday life is interrupted, we realize that we are like shipwrecked people trying to keep their balance on a miserable plank in the open sea, having forgotten where they came from and not knowing whether they are drifting. But once we fully accept this, life becomes easier and there is no longer any disappointment.

Knowledge exists in two forms - lifeless, stored in books, and alive, in the consciousness of men. The second form of existence is after all the essential one; the first, indispensable as it may be, occupies only an inferior position.

I have never belonged wholeheartedly to a country, a state, nor to a circle of friends, nor even to my own family. When I was still a rather precocious young man, I already realized most vividly the futility of the hopes and aspirations that most men pursue throughout their lives. Well-being and happiness never appeared to me as an absolute aim. I am even inclined to compare such moral aims to the ambitions of a pig.

The best that Gauss has given us was likewise an exclusive production. If he had not created his geometry of surfaces, which served Riemann as a basis, it is scarcely conceivable that anyone else would have discovered it. I do not hesitate to confess that to a certain extent a similar pleasure may be found by absorbing ourselves in questions of pure geometry.

Wisdom is not a product of schooling but of the lifelong attempt to acquire it.

Past is dead Future is uncertain; Present is all you have, So eat, drink and live merry.

To act intelligently in human affairs is only possible if an attempt is made to understand the thoughts, motives, and apprehension of one's opponent so fully that one can see the world through their eyes.