The essence of the liberal outlook lies not in what opinions are held, but in how they are held; instead of being held dogmatically, they are held tentatively, and with a consciousness that new evidence may at any moment lead to their abandonment.

To be able to fill leisure intelligently is the last product of civilization, and at present very few people have reached this level.

That the world is in a bad shape is undeniable, but there is not the faintest reason in history to suppose that Christianity offers a way out.

What the world needs is not dogma but an attitude of scientific inquiry combined with a belief that the torture of millions is not desirable, whether inflicted by Stalin or by a Deity imagined in the likeness of the believer

It can be shown that a mathematical web of some kind can be woven about any universe containing several objects. The fact that our universe lends itself to mathematical treatment is not a fact of any great philosophical significance.

One's work is never so bad as it appears on bad days, nor so good as it appears on good days.

Boys and girls should be taught respect for each other's liberty... and that jealousy and possessiveness kill love.