Science, by itself, cannot supply us with an ethic. It can show us how to achieve a given end, and it may show us that some ends cannot be achieved.

In art nothing worth doing can be done without genius; in science even a very moderate capacity can contribute to a supreme achievement.

Religions which have any very strong hold over men’s actions have generally some instinctive basis.

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

Why is propaganda so much more successful when it stirs up hatred than when it tries to stir up friendly feeling?

The desire to understand the world and the desire to reform it are the two great engines of progress, without which human society would stand still or retrogress.

Ideas and principles that do harm are, as a rule, though not always, cloaks for evil passions.

I do not believe that any peacock envies another peacock his tail, because every peacock is persuaded that his own tail is the finest in the world. The consequence of this is that peacocks are peaceable birds.

Nine-tenths of the appeal of pornography is due to the indecent feelings concerning sex which moralists inculcate in the young; the other tenth is physiological, and will occur in one way or another whatever the state of the law may be.

Philosophers, for the most part, are constitutionally timid, and dislike the unexpected. Few of them would be genuinely happy as pirates or burglars. Accordingly they invent systems which make the future calculable, at least in its main outlines.