All these reservations are needed in order to fix the scope of Stammler's investigation; but it would be a mistake to infer from them that we reject the starting point of the inquiry itself. Historical materialism--says Professor Stammler--has proved unable to give us a valid _science of society_: we, however, believe that this was not its main or original object. The two statements come practically to the same thing: the science of society is not contained in the literature of the materialistic theory. Professor Stammler adds that although historical materialism does not offer an acceptable social theory, it nevertheless gives a _stimulus of the utmost intensity_ towards the formation of such a theory. This seems to us a matter of merely individual psychology: suggestions and stimuli, as everyone knows, differ according to the mind that receives them. The literature of historical materialism has always aroused in us a desire to study history in the concrete, _i.e._, to reconstruct the actual historical process. In Professor Stammler, on the contrary, it arouses a desire to throw aside this meagre empirical history, and to work with abstractions in order to establish concepts and general points of view. The problems which he sets before himself, might be arrived at psychologically by many other paths. There is a tendency, at present, to enlarge unduly the boundaries of social studies. But Stammler rightly claims a definite and special subject for what ought to be called _social science_; that is _definite social data_. Social science must include nothing which has not _sociability_ as its determining cause. How can ethics ever be social science, since it is based on cases of conscience which evade all social rules? _Custom_ is the social fact, not _morality_. How can _pure economics_ or _technology_ ever be social science, since those concepts are equally applicable to the isolated individual and to societies? Thus in studying _social data_ we shall see that, considered in general, they give rise to two distinct theories. The first theory regards the concept _society_ from the _causal_ standpoint; the second regards it from the _teleological_ standpoint. Causality and teleology cannot be substituted the one for the other; but one forms the complement of the other.