We should not even destroy vipers and water-snakes and other creatures whose teeth and claws are dangerous, if we were able to tame them as we do other animals, or to prevent their being a peril to us: neither ought we, therefore, to hurt a man because he has done wrong, but lest he should do wrong, and our punishment should always look to the future, and never to the past, because it is inflicted in a spirit of precaution, not of anger: for if everyone who has a crooked and vicious disposition were to be punished, no one would escape punishment.