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

Power is sweet; it is a drug, the desire for which increases with a habit.

Punctuality is a quality the need of which is bound up with social co-operation.

Man is a rational animal—so at least I have been told. … Aristotle, so far as I know, was the first man to proclaim explicitly that man is a rational animal. His reason for this view was … that some people can do sums. … It is in virtue of the intellect that man is a rational animal. The intellect is shown in various ways, but most emphatically by mastery of arithmetic. The Greek system of numerals was very bad, so that the multiplication table was quite difficult, and complicated calculations could only be made by very clever people.

The man who has fed the chicken every day throughout its life at last wrings its neck instead, showing that more refined views as to the uniformity of nature would have been useful to the chicken.

The commonest objection to birth control is that it is against nature.

I say people who feel they must have a faith or religion in order to face life are showing a kind of cowardice, which in any other sphere would be considered contemptible. But when it is in the religious sphere it is thought admirable, and I cannot admire cowardice whatever sphere it is in.