SOCIAL DIFFERENTIATION 197 It is the social differentiation which has brought about this better distribution of freedom and restraint. It has destroyed the forced combination of heterogeneous indi- viduals and of heterogeneous interests of individuals in all- inclusive groups, and has created a social structure made up of associations that unite the homogeneous elements of heterogeneous circles. As a sociological form, this process of differentiation and integration manifests itself in the most varying social contents. But in the last analysis it is itself only a specific manifestation of a basic mental fune- tion which is operative in all fields of mental activity and most clearly manifest in the association of ideas. 1 Sh