All the conditions of happiness are realized in the life of the man of science.

Morality in sexual relations, when it is free from superstition, consists essentially in respect for the other person, and unwillingness to use that person solely as a means of personal gratification, without regard to his or her desires.

It can be shown that a mathematical web of some kind can be woven about any universe containing several objects. The fact that our universe lends itself to mathematical treatment is not a fact of any great philosophical significance.

In the ordinary business of life punctuality is . . . necessary.

I mean by intellectual integrity the habit of deciding vexed questions in accordance with the evidence, or of leaving them undecided where the evidence is inconclusive. This virtue, though it is underestimated by almost all adherents of any system of dogma, is to my mind of the very greatest social importance and far more likely to benefit the world than Christianity or any other system of organized beliefs.

[There has been] every kind of cruelty practiced upon all sorts of people in the name of religion.

God and Satan alike are essentially human figures, the one a projection of ourselves, the other of our enemies.