A happy life must be to a great extent a quiet life, for it is only in an atmosphere of quiet that true joy dare live.

Science, in its ultimate ideal, consists of a set of propositions arranged in a hierarchy, the lowest level of the hierarchy being concerned with particular facts, and the highest with some general law, governing everything in the universe. The various levels in the hierarchy have a two-fold logical connection, travelling one up, one down; the upward connection proceeds by induction, the downward by deduction.

A habit of basing convictions upon evidence, and of giving to them only that degree or certainty which the evidence warrants, would, if it became general, cure most of the ills from which the world suffers.

Every great idea starts out as a blasphemy.

The fact that a belief has a good moral effect upon a man is no evidence whatsoever in favor of its truth. I'm not contending in a dogmatic way that there is not a God. What I'm contending is that we don't know that there is. I don't like the word "absolute." I don't think there is anything absolute whatever. The moral law, for example, is always changing. At one period in the development of the human race, almost everybody thought cannibalism was a duty.

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.

The first step in a fascist movement is the combination under an energetic leader of a number of men who possess more than the average share of leisure, brutality, and stupidity. The next step is to fascinate fools and muzzle the intelligent, by emotional excitement on the one hand and terrorism on the other.