Sociology, as well as most social sciences, alternates between two approaches: in one case, social phenomena should be understood through a rational actor, in the other, social phenomena is the result of the possibility to understand relations. These two perspectives, although contradictory, often cohabit, even within the same theory; sociality cannot be simultaneously the pure product of individual actions and of human interactions or of relations between social phenomena. This is why interactionism imposes itself upon individualist theories and why the ideology of a rational, free, interested, intentional, and strategic actor does not impend all relational research undertakings. Relational approaches are essential to social sciences simply because there is no individual without human interactions and because there is no social phenomena which is not either a combination of relations or itself in relation with other phenomena.