“Not to be absolutely certain is, I think, one of the essential things in rationality.”

None of our beliefs are quite true; all have at least a penumbra of vagueness and error.

Language serves not only to express thought but to make possible thoughts that could not exist without it.

The secret of happiness is very simple: let your interests be as wide as possible, and let your reactions to the things and persons that interest you be as far as possible friendly rather than hostile.

One must care about a world one will not see.

To write a tragedy, a man must feel the tragedy. To feel tragedy, a man must be aware of the world in which he lives. Not only with his mind, but with his blood and sinews.

The demand for certainty is one that is natural to man but is nevertheless an intellectual vice.

The hardest thing to learn in life is which bridge to cross and which to burn.

Freedom of opinion can only exist when the government thinks itself secure.

Most people would sooner die than think; in fact, they do so.

If there were in the world today any large number of people who desired their own happiness more than they desired the unhappiness of others, we could have paradise in a few years.

I hate being all tidy like a book in a library where nobody reads – prison is horribly like that.

Philosophy, from the earliest times, has made greater claims, and achieved fewer results, than any other branch of learning.

No nation was ever so virtuous as each believes itself, and none was ever so wicked as each believes the other.

I consider the official Catholic attitude on divorce, birth control, and censorship exceedingly dangerous to mankind.

Even if all the experts agree, they may well be mistaken.

Few people can be happy unless they hate some other person, nation, or creed.