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economics. Moreover, this organic contractualism has abso- lutely nothing in common with Jean Jacques Rousseau's theory of the social contract; it is also the antipode of the con- tractualism of Yves Guiot and of radical liberalism in general ; in implies the constant intervention of the collective body in its own organization and reorganization ; it is a social, and not an individualistic, contractualism.
Societies in general are distinguished from individual organ- isms by their greater mass and their superior complexity ; every society, even the simplest, is larger and more complicated than a zoological organism.
This double difference in the quantity of the social mass and in the variety of its combinations corresponds to this general phenomena of nature, that the more a substance is extended the more it is subject to variations ; it being impossible for the environment to act in the same manner upon each of the parts of the mass because of their different situations.
We may say also that the quantitative differences are the profound source of the distinctive qualitative characteristics of social bodies and of their successive differentiations, as will become more apparent in the chapter devoted to social aggre- gates.
The variations of the social body are also favored by the fact that it is more discrete or diffuse than individual organisms ; its constituent units are less intimately bound together. Its structure is less symmetrical than zoological structure, and inor- ganic or intermediary structures, and than organisms such as crystals. These characteristics imply the greater plasticity of society, and this plasticity has in turn the corollary of modi- fiability.
From the point of view of the interpretation of the natural structure and functioning of societies, a capital phenomenon here appears. Social bodies are not merely the result of the combination of inorganic bodies and of inferior organisms; another factor enters into their organization : the human species, population. This second factor, by virtue of its own constitution and its action and reaction upon the first, consists of sensible
