The happiness that is genuinely satisfying is accompanied by the fullest exercise of our faculties and the fullest realization of the world in which we live.

I do not think any reasonable person can doubt that in India, China and Japan, if the knowledge of birth control existed, the birthrate would fall very rapidly

The harm that theology has done is not to create cruel impulses, but to give them the sanction of what professes to be lofty ethic, and to confer an apparently sacred character upon practices which have come down from more ignorant and barbarous times.

The morality of work is the morality of slaves, and the modern world has no need of slavery.

All definite knowledge - so I should contend - belongs to science; all dogma as to what surpasses definite knowledge belongs to theology. But between theology and science there is a No Man's Land, exposed to attack by both sides; this No Man's Land is philosophy.

To avoid the various foolish opinions to which mankind are prone, no superhuman genius is required. A few simple rules will keep you, not from all error, but from silly error.

If the West can claim superiority in anything, it is . . . in science and scientific technique.