Everything is vague to a degree you do not realize till you have tried to make it precise.

It is not my prayer and humility that you cause things to go as you wish, but by acquiring a knowledge of natural laws.

I used often to go to America during Prohibition, and there was far more drunkenness there then than before; the prohibition of pornography has much the same effect.

Unrestricted nationalism is, in the long run, incompatible with world peace.

Inferences of Science and Common Sense differ from those of deductive logic and mathematics in a very important respect, namely, when the premises are true and the reasoning correct, the conclusion is only probable.

Mathematics is, I believe, the chief source of the belief in eternal and exact truth, as well as a sensible intelligible world.

I should like to believe my people's religion, which was just what I could wish, but alas, it is impossible. I have really no religion, for my God, being a spirit shown merely by reason to exist, his properties utterly unknown, is no help to my life. I have nor the parson's comfortable doctrine that every good action has its reward, and every sin is forgiven. My whole religion is this: do every duty, and expect no reward for it, either here or hereafter.