The history of ideas has changed its conception of the relation between individuals and society several times. The Aristotelian tradition formulated it as a relation between individuals (friendship) using the concepts of selfreference and alter ego. PARSONS sees the relation as a relation between subsystems within the framework of an encompassing action system using the concept of interpenetration, not of individuals but of the personal and the social system. It is proposed to change this conception again. Interpenetration can be characterized as a relation between system and environment in which environmental systems contribute their own capacity for variation to stabilize the patterns of another system on a higher level. This conception has its roots in the early anthropology of the bourgeoise revolution (1650-1750). It can be used to elaborate on problems of socialization and of rationality within the framework of theories with multiple system references.