The taboo against nakedness is an obstacle to a decent attitude on the subject of sex.

It is not what the man of science believes that distinguishes him, but how and why he believes it. His beliefs are tentative, not dogmatic; they are based on evidence, not on authority or intuition.

The observer, when he seems to himself to be observing a stone, is really, if physics is to be believed, observing the effects of the stone upon himself.

There will still be things that machines cannot do. They will not produce great art or great literature or great philosophy; they will not be able to discover the secret springs of happiness in the human heart; they will know nothing of love and friendship.

The human race may well become extinct before the end of the century.

No man treats a motorcar as foolishly as he treats another human being. When the car will not go, he does not attribute its annoying behavior to sin; he does not say, 'You are a wicked motorcar, and I shall not give you any more petrol until you go.' He attempts to find out what is wrong and to set it right.

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.