Let us not decide what is good, but let it be considered good not to decide it.

I have argued with him on almost every subject in the world, and we have always been on opposite sides, without affectation or animosity... It is necessary to disagree with him as much as I do, in order to admire him as I do; and I am proud of him as a foe even more than as a friend.

Science is the study of the admitted laws of existence, which cannot prove a universal negative about whether those laws could ever be suspended by something admittedly above them. It is as if we were to say that a lawyer was so deeply learned in the American Constitution that he knew there could never be a revolution in America.

It is true that there is a thing crudely called charity, which means charity to the deserving poor; but charity to the deserving is not charity at all, but justice. It is the undeserving who require it, and the ideal either does not exist at all, or exists wholly for them.

The one created thing which we cannot look at is the one thing in the light of which we look at everything.

When a person has found something which he prefers to life itself, he for the first time has begun to live.

They say travel broadens the mind, but you must have the mind.