Toward the end of the last century a positivist sociological thinking tended to supersede the metaphysical-historical and the utilitarian-analytical. All phenomena were determined by inexorable natural laws to be discovered by observation. Moral and social and hence legal phenomena were governed by laws as completely beyond the power of conscious human control as the movements of the planets. We might discover these laws by observation of social phenomena and might learn to submit to them intelligently instead of rashly or ignorantly defying them. But we could hope to do no more. Except as he could learn to plot some part of the inevitable curve of legal development and save us from futile flyings in the face of the laws by which legal evolution was inevitably governed, the jurist was powerless. Many combined this mode of thought with or grafted it on the metaphysical-historical theory and fought valiantly against the social legislation of the last decade of the nineteenth century and the first decade of the present century with this reinforced juristic pessimism as a base. Superficially it appeared that the Greek idea of the naturally just, which in its Roman form of natural law and its eighteenth-century form of natural rights had made for a creative legal science as long as such a science had existed, had at length exhausted its possibilities. Today, however, we hear of a revival of natural law. Philosophy of law is raising its head throughout the world. We are asked to measure rules and doctrines and institutions and to guide the application of law by reference to the end of law and to think of them in terms of social utility. We are invited to subsume questions of law and of the application of law under the social ideal of the time and place. We are called upon to formulate the jural postulates of the civilization of the time and place and to measure law and the application of law thereby in order that law may further civilization and that the legal materials handed down with the civilization of the past may be made an instrument of maintaining and furthering the civilization of the present. We are told that observation shows us social interdependence through similarity of interest and through division of labor as the central fact in human existence and are told to measure law and the application of law functionally by the extent to which they further or interfere with this interdependence. For the era of legal self-sufficiency is past. The work of assimilating what had been received into the law from without during the period of equity and natural law has been done. The possibilities of analytical and historical development of the classical materials have been substantially exhausted. While jurists have been at these tasks, a new social order has been building which makes new demands and presses upon the legal order with a multitude of unsatisfied desires. Once more we must build rather than merely improve; we must create rather