Science, in its ultimate ideal, consists of a set of propositions arranged in a hierarchy, the lowest level of the hierarchy being concerned with particular facts, and the highest with some general law, governing everything in the universe. The various levels in the hierarchy have a two-fold logical connection, travelling one up, one down; the upward connection proceeds by induction, the downward by deduction.

Marriage is for women the commonest mode of livelihood, and the total amount of undesired sex endured by women is probably greater in marriage than in prostitution.

When you meet with opposition, even if it should be from your husband or your children, endeavor to overcome it by argument and not by authority, for a victory dependent upon authority is unreal and illusory.

I suggest to young professors that their first work should be written in a jargon only to be understood by the erudite few. With that behind them, they can ever after say what they have to say in a language 'understand of the people.'

Freedom in education has many aspects. There is first of all freedom to learn or not to learn. Then there is freedom as to what to learn. And in later education there is freedom of opinion.

My sad conviction is that people can only agree about what they're not really interested in.

Orthodoxy is the grave of intelligence, no matter what orthodoxy it may be.