If I could do it all again, I'd be a plumber.
In theory, theory and practice are the same. In practice, they are not.
The mathematician knows some things, no doubt, but not those things one usually wants to get from him.
The world we have created is a product of our thinking.
To me it is enough to wonder at the secrets
Everyone knew it was impossible, until a fool who didn't know came along and did it.