Professor Stammler speaks readily of a _monism_ of the social life, and accepts as suitable and accurate the name _materialism_ as applied to Marx's conception of history, and connects this _materialism_ with metaphysical materialism, applying to it also Lange's statement, viz., that 'materialism may be the first and lowest step of philosophy, but it is also the most substantial and solid.' For him historical materialism offers truth, but not the whole truth, since it regards as real the _matter_ only and not the _form_ of social life; hence the necessity of completing it by restoring the _form_ to its place, and fixing the relation between _form_ and _matter_, combining the two in the unity of _social life_. We doubt whether Engels and his followers ever understood the phrase _social materialism_ in the sense which Stammler assigns to it. The parallel drawn between it and metaphysical materialism seems to us somewhat arbitrary. We come to the group of concrete sciences, _i.e._, those which have for their subject society as given in history. No one who has had occasion to consider the problem of the classification of the sciences, will be inclined to give the character of independent and autonomous sciences to studies of the practical problems of this or that society, and to jurisprudence, and the technical study of law. This latter is only an interpretation or explanation of a given existing legal system, made either for practical reasons, or as simple historical knowledge. But what we think merits attention more than these questions of terminology and classification, is the conception of _social economics_, advanced by Stammler; of the second, that is, of the concrete social sciences, enumerated above. The difficulties arising out of this conception are more serious, and centre on the following points; whether it is a new and valid conception, or whether it should be reduced to something already known; or finally whether it is not actually erroneous.