CONCLUSION 271 that he makes a clear distinction between history and sci- ence, is perhaps his most valuable contribution. A study of his works will make possible an understanding of the function and method of the social sciences which ought to do much for real progress in these fields. With regard to Simmel’s conception of sociology, there have been critics who have objected to his differentiation between form and content. As all scientific investigation rests in the last instance upon an abstraction, there seems little justification for a condemnation of his sociology on that ground. The particular difficulty about the sociologi- cal abstraction is a problem of technique, not of method, and there is no reason for assuming that it will not be solved in time. It is due to the unfamiliarity with the new differ- entiation, not to any inherent obstacles. The differentiation between the form and the content of the social life is in essence not more unnatural than the similar differentiation between the form and the content of the psychological process in the individual mind. The differentiation of the content of the social life in the fields of different social sci- ences has also become an established fact during the last century. It has taken time, but it came about gradually and naturally like the similar differentiation in the ancient world. The early Greeks would probably have thought a differentiation of the social life in the fields of ethics, juris- prudence, and political science an impossibility. Yet that differentiation had been practically accomplished by the time of the Roman lawyers, and it was only with that differentiation that real progress began to be made. We may therefore expect that in time the differentiation be- tween the content and the form of society will come just as naturally as that between the form and the content of a psychological process or between the logical form and the content of an argument. Simmel’s conception of sociology and its subject-matter