Very few men can be genuinely happy in a life involving continual self-assertion against the skepticism of the mass of mankind, unless they can shut themselves up in a coterie and forget the cold outer world. The man of science has no need of a coterie, since he is thought well of by everybody except his colleagues. The artist, on the contrary, is in the painful situation of having to choose between being despised and being despicable.

The reformative effect of punishment is a belief that dies hard, chiefly I think, because it is so satisfying to our sadistic impulses.

Do not feel certain of anything.

The moral thing I should wish to say to them is very simple; I should say: "Love is wise - Hatred is foolish." In this world, which is getting more and more closely interconnected, we have to learn to tolerate each other.

I do not pretend to start with precise questions. I do not think you can start with anything precise. You have to achieve such precision as you can, as you go along.

I like mathematics because it is not human and has nothing particular to do with this planet or with the whole accidental universe - because, like Spinoza's God, it won't love us in return.

We believe, first and foremost, what makes us feel that we are fine fellows.