A stupid man's report of what a clever man says can never be accurate, because he unconsciously translates what he hears into something he can understand.

Intelligence, it might be said, has caused our troubles; but it is not unintelligence that will cure them. Only more and wiser intelligence can make a happier world

One of the chief obstacles to intelligence is credulity, and credulity could be enormously diminished by instructions as to the prevalent forms of mendacity. Credulity is a greater evil in the present day than it ever was before, because, owing to the growth of education, it is much easier than it used to be to spread misinformation, and, owing to democracy, the spread of misinformation is more important than in former times to the holders of power.

Zeno was concerned with three problems... These are the problem of the infinitesimal, the infinite, and continuity.

Calculus required continuity, and continuity was supposed to require the infinitely little; but nobody could discover what the infinitely little might be.

The secret to happiness is to face the fact that the world is horrible.

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.