This circumstance tends to simplify the sociologist’s task very materially. While the application of the polity which he evolves will require to take account of the peculiar traditions and institutions of different groups, he will be free to work out his polity in terms which are independent of the present exclusive and conflicting aims of the groups which compose the world of man. He will state the ultimate problems of society in Germany in the same terms as he will state those in America; for he will necessarily be dealing with the one factor which is common to both. There cannot be a distinctive social science in Germany and another in America, differing from one another in essentials and both at the same time being true. There will be endless variety in the methods by which social principles are applied by different groups; for we cannot write off the past of a people and the institutions in which its history is embodied. Yet there can be no true sociology in England or in Germany unless its postulates are equally valid in America. In other words these postulates must be drawn from a disinterested study of personality. They will not concern themselves with the welfare of a particular group, in whatever terms that welfare may be defined. But they will be concerned with the good of the world of groups because they are derived from the one fact which is common to and underlies them all, and which, despite conflicting aims still binds human groups together in a permanent unity, namely, personality. IV