"All that makes existence valuable to any one, depends on the enforcement of restraints upon the actions of other people. Some rules of conduct, therefore, must be imposed, by law in the first place, and by opinion on many things which are not fit subjects for the operation of law. What these rules should be, is the principal question in human affairs; but if we except a few of the most obvious cases, it is one of those which least progress has been made in resolving. No two ages, and scarcely any two countries, have decided it alike; and the decision of one age or country is a wonder to another. (p. 10)"