Many a young lady does not realize just how strong her love for a young man is until he fails to pass the approval test with her parents. There is no fear in love; but perfect love casteth out fear. Of all forms of caution, caution in love is the most fatal. There are only two truly infinite things, the universe and stupidity. And I am unsure about the universe.

As far as I'm concerned, I prefer silent vice to ostentatious virtue.

The most difficult part about understanding something is that we understand it all.

What good is a reputation not put to good use.

To invent something, all you need is imagination and a big pile of junk.

It stands to the everlasting credit of science that by acting on the human mind it has overcome man's insecurity before himself and before nature.

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.