If we turn to the ideas which have obtained in conscious thinking about the end of law, we may recognize three which have held the ground successively in legal history and a fourth which is beginning to assert itself. The first and simplest idea is that law exists in order to keep the peace in a given society; to keep the peace at all events and at any price. This is the conception of what may be called the stage of primitive law. It puts satisfaction of the social want of general security, stated in its lowest terms, as the purpose of the legal order. So far as the law goes, other individual or social wants are ignored or are sacrificed to this one. Accordingly the law is made up of tariffs of exact compositions for every detailed injury instead of principles of exact reparation, of devices to induce or coerce submission of controversies to adjudication instead of sanctions, of regulation of self-help and self-redress instead of a general prohibition thereof, and of mechanical modes of trial which at any rate do not admit of argument instead of rational modes of trial involving debate and hence dispute and so tending to defeat the purpose of the legal order. In a society organized on the basis of kinship, in which the greater number of social wants were taken care of by the kin-organizations, there are two sources of friction: the clash of kin-interests, leading to controversies of one kindred with another, and the kinless man, for whom no kin-organization is responsible, who also has no kin-organization to stand behind him in asserting his claims. Peace between kindreds and peace between clansmen and the growing mass of non-gentile population is the unsatisfied social want to which politically organized society must address itself. The system of organized kindreds gradually breaks down. Groups of kinsmen cease to be the fundamental social units. Kin-organization is replaced by political organization as the primary agency of social control. The legal unit comes to be the free citizen or the free man. In this transition regulation of self-redress and prevention of private war among those who have no strong clan-organizations to control them or respond for them are demanded by the general security. The means of satisfying these social wants are found in a legal order conceived solely in terms of keeping the peace.