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.

Only mathematics and mathematical logic can say as little as the physicist means to say.

One of the chief obstacles to intelligence is credulity, and credulity could be enormously diminished by instructions as to the prevalent forms of mendacity. Credulity is a greater evil in the present day than it ever was before, because, owing to the growth of education, it is much easier than it used to be to spread misinformation, and, owing to democracy, the spread of misinformation is more important than in former times to the holders of power.

If a Black Death could be spread throughout the world once in every generation survivors could procreate freely without making the world too full.

When I was a child . . . Only virtue was prized, virtue at the expense of intellect, health, happiness, and every mundane good.

It is one of the defects of modern higher education that it has become too much a training in the acquisition of certain kinds of skill, and too little an enlargement of the mind and heart by an impartial survey of the world.

My own belief is that in most ages and in most places obscure psychological forces led men to adopt systems involving quite unnecessary cruelty, and that this is still the case among the most civilized races at the present day.