In Anglo-American law, the justification of property on a natural principle of occupation of ownerless things got currency through Blackstone. As between Locke on the one side and Grotius and Pufendorf on the other, Blackstone was not willing to commit himself to the need of assuming an original pact. Apparently he held that a principle of acquisition by a temporary power of control co-extensive with possession expressed the nature of man in primitive times and that afterwards, with the growth of civilization, the nature of man in a civilized society was expressed by a principle of complete permanent control of what had been occupied exclusively, including as a necessary incident of such control the _ius disponendi_. Maine has pointed out that this distinction between an earlier and a later stage in the natural right of property grew out of desire to bring the theory into accord with Scriptural accounts of the Patriarchs and their relations to the land grazed by their flocks. In either event the ultimate basis is taken to be the nature of man as a rational creature, expressed in a natural principle of control of things through occupation or in an original contract providing for such ownership. With the revival of natural law in recent years a new phase of the justification of property upon the basis of human nature has arisen. This was suggested first by economists who deduced property from the economic nature of man as a necessity of the economic life of the individual in society. Usually it is coupled with a psychological theory on the one side and a social-utilitarian theory on the other side. In the hands of writers on philosophy of law it has often taken on a metaphysical color. From another standpoint, what are essentially natural-law theories have been advocated by socialists, either deducing a natural right of the laborer to the whole produce of his labor from a "natural" principle of creation or carrying out the idea of natural qualities of the individual human being to the point of denying all private property as a "natural" institution and deducing a general regime of _res communes_ or _res publicae_.