It was the duty of wives to submit to husbands, not of husbands to submit to wives. . . men have stronger muscles than women.

Mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true.

Change is one thing, progress is another.

Most of the greatest evils that man has inflicted upon man have come through people feeling quite certain about something which, in fact, was false.

The key to happiness is accepting one unpleasant reality every day.

Love, children, and work, are the great sources of fertilizing contact between the individual and the rest of the world.

Science may set limits to knowledge, but should not set limits to imagination.