God exists since mathematics is consistent, and the Devil exists since we cannot prove it.
Intuition makes much of it; I mean by this the faculty of seeing a connection between things that in appearance are completely different; it does not fail to lead us astray quite often.
What is crucial is there be laws.
First rate mathematicians choose first rate people, but second rate mathematicians choose third rate people.
Rigour is to the mathematician what morality is to men.