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conditions of life for that variation. The degenerations caused through individualization lead partly to voluntary, partly to forced, subordina- tion of individuals in a social union. The more life incites individual interests, the more important is social constraint to limit the degenera- ting differentiation, in order not to endanger the species and its social structures through war of all against all. Since, however, all interests are ever firmly anchored in the physiological interest, nature always brings back with its conditions of life all extravagances of individual and social development, whether they be the product of excessive dif- ferentiation or of inexpedient socialization, to the paths of social necessity founded in the needs of nourishment and propagation. The first sure concept which we have of the nature of our being is interest, and this is also the guiding principle in the biological as well as in the social process. Since inherent interest is modified in creatures through the change of life-conditions, the causes of social structures becoming differentiated are given. We must recognize clearly the fact that varia- tion of interests goes in advance of the phenomena of the social process ; just as the natural change of life-conditions goes in advance of this differentiation of interest. The cause of this differentiation lies in the needs of men, and that of change of life-conditions in universal, natural occurrences with their consequences for organic and social life. The innate and acquired interest is the source of all human needs, and, in its changeable manifold forms, the guiding motive of all movements in the biological, psychical, and social process of the individual and of humanity. ' Interest,' therefore, in positive philosophy takes the place of the contradictory concept ' purpose,' which gave the widest oppor- tunity for every erroneous presupposition and every vagueness concern- ing the relation of mind and nature. Indeed, the vanishing of this concept is alone a far-reaching step for the furtherance of metaphysical knowledge."
The fourth division is entitled : "The Social Process of the Human Race." It discusses successively: (i) " Primitive Social Structures ; " (2) "The Evolution of Higher Social Structures," which through a blending of militant with industrial tribes is claimed to have pro- duced the state and the people {das Volk) ; (3) " Social Differentiation within the State," which, according to Ratzenhofer's view, produced the nation {die Nation) ; (4) " Social Differentiation of the Sphere of Civilization" {Kuliurkreis) ; (5) "The Extension of a Dominating Social Process over Humanity" (commerce, colonization, migration, etc.). All these chapters contain thoughts which are worth reading, but
