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.

Everything is vague to a degree you do not realize till you have tried to make it precise.

Truth is a shining goddess, always veiled, always distant, never wholly approachable, but worthy of all the devotion of which the human spirit is capable.

Answering questions is a major part of sex education. Two rules cover the ground. First, always give a truthful answer to a question; secondly, regard sex knowledge as exactly like any other knowledge.

Most of the greatest evils that man has inflicted upon man have come through people feeling quite certain about something which, in fact, was false.

Love can only flourish as long as it is free and spontaneous; it tends to be killed by the thought that it is a duty. To say that it is your duty to love so-and-so is the surest way to cause you to hate him or her.

Belief in God and a future life makes it possible to go through life with less of stoic courage than is needed by skeptics.