I have remarked very clearly that I am often of one opinion when I am lying down and of another when I am standing up.

Do not say hypothesis, and even less theory: say way of thinking.

Man is always partial and is quite right to be. Even impartiality is partial.

The highest level than can be reached by a mediocre but experienced mind is a talent for uncovering the weaknesses of those greater than itself.

One is rarely an impulsive innovator after the age of sixty, but one can still be a very fine orderly and inventive thinker. One rarely procreates children at that age, but one is all the more skilled at educating those who have already been procreated, and education is procreation of another kind.

A man has virtues enough if he deserves pardon for his faults on account of them.

So-called professional mathematicians have, in their reliance on the relative incapacity of the rest of mankind, acquired for themselves a reputation for profundity very similar to the reputation for sanctity possessed by theologians.