I do not believe that a man should be restrained in his daily actions by being afraid of punishment after death or that he should do things only because in this way he will be rewarded after he dies. This does not make sense. The proper guidance during the life of a man should be the weight that he puts upon ethics and the amount of consideration that he has for others.

I now see the necessity of a beginning.

The only sure way to avoid making mistakes is to have no new ideas.

I don't need to know everything, I just need to know where to find it, when I need it

The most practical solution is a good theory.

It should be possible to explain the laws of physics to a barmaid.

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.