Although this may seem a paradox, all exact science is based on the idea of approximation. If a man tells you he knows a thing exactly, then you can be safe in inferring that you are speaking to an inexact man.

The time you enjoy wasting is not wasted time.

Measures of sterilization should, in my opinion, be very definitely confined to persons who are mentally defective

The fact that a belief has a good moral effect upon a man is no evidence whatsoever in favor of its truth. I'm not contending in a dogmatic way that there is not a God. What I'm contending is that we don't know that there is. I don't like the word "absolute." I don't think there is anything absolute whatever. The moral law, for example, is always changing. At one period in the development of the human race, almost everybody thought cannibalism was a duty.

Envy ... is one form of a vice, partly moral, partly intellectual, which consists in seeing things never in themselves but only in their relations.

The mind is a strange machine which can combine the materials offered to it in the most astonishing ways.

Continuity of purpose is one of the most essential ingredients of happiness in the long run, and for most men that comes chiefly through their work.