What the world needs is not dogma but an attitude of scientific inquiry.

The Mormons had a divine revelation in favour of polygamy, but under pressure from the United States Government they discovered that the revelation was not binding.

What will be the good of the conquest of leisure and health, if no one remembers how to use them?

Man is a rational animal – so at least I have been told. Throughout a long life, I have looked diligently for evidence in favour of this statement, but so far I have not had the good fortune to come across it, though I have searched in many countries spread over three continents.

My whole religion is this: do every duty, and expect no reward for it, either here or hereafter.

Righteousness cannot be born until self-righteousness is dead.

It is for this reason that rationality is of supreme importance to the well-being of the human species...even more, in those less fortunate times in which it is despised and rejected as the vain dream of men who lack the virility to kill where they cannot agree.