There is in Aristotle an almost complete absence of what may be called benevolence or philanthropy. The sufferings of mankind . . . there is no evidence that they cause him unhappiness except when the sufferers happen to be his friends.

A priori Logical propositions are such as can be known a priori without study of the actual world.

When we have told how things behave when they are electrified, and under what circumstances they are electrified, we have told all there is to know

Arithmetic must be discovered in just the same sense in which Columbus discovered the West Indies, and we no more create numbers than he created the Indians.

When considering marriage one should ask oneself this question; 'will I be able to talk with this person into old age?' Everything else is transitory, the most time is spent in conversation.

The true spirit of delight...is to be found in mathematics as surely as in poetry.

More cranks take up unfashionable errors than unfashionable truths.