There are few general propositions concerning the age to which we belong which seem at first sight likely to be received with readier concurrence than the assertion that the society of our day is mainly distinguished from that of preceding generations by the largeness of the sphere which is occupied in it by Contract. Some of the phenomena on which this proposition rests are among those most frequently singled out for notice, for comment, and for eulogy. Not many of us are so unobservant as not to perceive that in innumerable cases where old law fixed a man's social position irreversibly at his birth, modern law allows him to create it for himself by convention; and indeed several of the few exceptions which remain to this rule are constantly denounced with passionate indignation. The point, for instance, which is really debated in the vigorous controversy still carried on upon the subject of negro servitude, is whether the status of the slave does not belong to bygone institutions, and whether the only relation between employer and labourer which commends itself to modern morality be not a relation determined exclusively by contract. The recognition of this difference between past ages and the present enters into the very essence of the most famous contemporary speculations. It is certain that the science of Political Economy, the only department of moral inquiry which has made any considerable progress in our day, would fail to correspond with the facts of life if it were not true that Imperative Law had abandoned the largest part of the field which it once occupied, and had left men to settle rules of conduct for themselves with a liberty never allowed to them till recently. The bias indeed of most persons trained in political economy is to consider the general truth on which their science reposes as entitled to become universal, and, when they apply it as an art, their efforts are ordinarily directed to enlarging the province of Contract and to curtailing that of Imperative Law, except so far as law is necessary to enforce the performance of Contracts. The impulse given by thinkers who are under the influence of these ideas is beginning to be very strongly felt in the Western world. Legislation has nearly confessed its inability to keep pace with the activity of man in discovery, in invention, and in the manipulation of accumulated wealth; and the law even of the least advanced communities tends more and more to become a mere surface-stratum having under it an ever-changing assemblage of contractual rules with which it rarely interferes except to compel compliance with a few fundamental principles or unless it be called in to punish the violation of good faith.