The greatest challenge to any thinker is stating the problem in a way that will allow a solution.

Change is scientific; progress is ethical; change is indubitable, whereas progress is a matter of controversy.

Civilized life has altogether grown too tame, and, if it is to be stable, it must provide a harmless outlets for the impulses which our remote ancestors satisfied in hunting.

(on A History of Western Philosophy) I was sometimes accused by reviewers of writing not a true history but a biased account of the events that I arbitrarily chose to write of. But to my mind, a man without a bias cannot write interesting history - if, indeed, such man exists.

Love cannot exists as a duty; to tell a child that it ought to love its parents and its brother and sisters is utterly useless, if not worse.

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.

Most political leaders acquire their position by causing large numbers of people to believe that these leaders are actuated by altruistic desires