Natural world is governed by evolution. Social world is governed by evolution. Which means that evolution is a process of successive differentiation and integration. Viewed society as an organism. Like any living thing, society is a matter of continuing growth and increasing structural complexity Dissimilar parts have differing functions, which are not merely diverse, but must function together for the whole to exist.
Body can have aliments- germs, worms, so can social systems.
Evolution is basis of progress, social change Story of growth of tribe. Social growth involves not only the multiplication of groups and the union of groups, but also increasing density and solidarity- integration follows differentiation means not merely larger mass, but the progress of the mass toward coherence due to the closeness of the parts Evolution does seem to describe society Spencer illustrated the society transition from homogeneity to heterogeneity by contrasting primitive and modern societies. The primitive is alike in all of its parts, the civilized nation is full of structural and functional unlikeness. Tribe is held together by subordination to the leader. Civilized nations are held together by integration.