The paper is an introduction to our volume about mutual relations between sociology and cultural anthro
pology. Both disciplines have been described as systems of communication; we use concepts cited above and the idea of
systems’ differentiation to account the problem of these systems’ boundaries in diachronic perspective. We have chosen
texts constitutive for sociological and anthropological traditions to show how these disciplines (as systems) used to
differentiate themselves from their environment, shut themselves, and marked their boundaries; and later – because of
multiple and heterogeneous references to the environment – could not maintain them any more.