Reason may be a small force, but it is constant, and works always in one direction, while the forces of unreason destroy one another in futile strife.

The only thing that will redeem mankind is cooperation.

The man who suffers from a sense of sin is suffering from a particular kind of self-love. In all this vast universe the thing that appears to him of most importance is that he himself should be virtuous. It is a grave defect in certain forms of traditional religion that they have encouraged this particular kind of self-absorption.

If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way.

The greatest challenge to any thinker is stating the problem in a way that will allow a solution.

It is only through imagination that men become aware of what the world might be; without it, ‘progress’ would become mechanical and trivial.

The true spirit of delight...is to be found in mathematics as surely as in poetry.