Beware the man of the single book

To create a healthy philosophy you should renounce metaphysics but be a good mathematician.

To save the world requires faith and courage: faith in reason, and courage to proclaim what reason shows to be true.

Opinions which justify cruelty are inspired by cruel impulses.

Organic life, we are told, has developed gradually from the protozoon to the philosopher, and this development, we are assured, is indubitably an advance. Unfortunately it is the philosopher, not the protozoon, who gives us this assurance.

Fools and fanatics are always so certain of themselves.

An atheist, like a Christian, holds that we can know whether or not there is a God. The Christian holds that we can know there is a God; the atheist, that we can know there is not. The Agnostic suspends judgment, saying that there are not sufficient grounds either for affirmation or for denial. At the same time, an Agnostic may hold that the existence of God, though not impossible, is very improbable; he may even hold it so improbable that it is not worth considering in practice. In that case, he is not far removed from atheism.