Better keep yourself clean and bright; you are the window through which you must see the world.

A contract for better for worse is a contract that should not be tolerated.

You do not settle whether an argument is justified by merely showing that it is of some use. The distinction is not between useful and useless experiments but between barbarous and civilized behaviour. Vivisection is a social evil because if it advances human knowledge, it does so at the expense of human character.

There is nothing on earth intended for innocent people so horrible as a school.

New opinions often appear first as jokes and fancies, then as blasphemies and treason, then as questions open to discussion, and finally as established truths.

Marriage is an alliance entered into by a man who can't sleep with the window shut, and a woman who can't sleep with the window open.

Both optimists and pessimists contribute to society. The optimist invents the aeroplane, the pessimist the parachute.