My doctor said to me afterwards, 'When you were ill you behaved like a true philosopher. Every time you came to yourself you made a joke.' I never had a compliment that pleased me more.

Religions that teach brotherly love have been used as an excuse for persecution, and our profoundest scientific insight is made into a means of mass destruction.

America... where law and custom alike are based upon the dreams of spinsters...

The man who pursues happiness wisely will aim at the possession of a number of subsidiary interests in addition to those central ones upon which his life is built.

Although this may seem a paradox, all exact science is dominated by the idea of approximation. When a man tells you that he knows the exact truth about anything, you are safe in inferring that he is an inexact man. Every careful measurement in science is always given with the probable error ... every observer admits that he is likely wrong, and knows about how much wrong he is likely to be.

There is no reason to suppose that the world had a beginning at all. The idea that things must have a beginning is really due to the poverty of our thoughts.

Collective wisdom, alas, is no adequate substitute for the intelligence of individuals. Individuals who opposed received opinions have been the source of all progress, both moral and intellectual. They have been unpopular, as was natural.