There is no need to worry about mere size. We do not necessarily respect a fat man more than a thin man. Sir Isaac Newton was very much smaller than a hippopotamus, but we do not on that account value him less.

The whole realm of thought and opinion is utterly unsuited to public control; it ought to be as free, and as spontaneous as is possible. The state is justified in insisting that children shall be educated, but it is not justified in forcing their education to proceed on a uniform plan and to be directed to the production of a dead level of glib uniformity.

Contempt for happiness is usually contempt for other people's happiness, and is an elegant disguise for hatred of the human race.

Humanistic ethics is based on the principle that only humans themselves can determine the criterion for virtue and not an authority transcending us.

In the first place a philosophical proposition must be general. It must not deal specially with things on the surface of the earth, or within the solar system, or with any other portion of space and time. . . . This brings us to a second characteristic of philosophical propositions, namely that they must be a priori. A philosophical proposition must be such as can neither be proved nor disproved by empirical evidence. . . . Philosophy, if what has been said is correct, becomes indistinguishable from logic as that word has now come to be used.

Calculus required continuity, and continuity was supposed to require the infinitely little; but nobody could discover what the infinitely little might be.

Ethics is in origin the art of recommending to others the sacrifices required for cooperation with oneself.