Luhmann opens his lecture course by telling a sociology audience that their discipline is in theoretical crisis. It keeps circling back to Weber, Marx, Simmel and Durkheim, has some middle-range theories drawn from empirical work, and has almost nothing to say about ecological problems or the therapeutic demands of modern life. The interesting developments, he suggests, are happening outside the field.

The lectures therefore begin with the structural and maintenance functionalism of American sociology in the 1940s and 1950s, and with Parsons, showing where each ran up against its limits and why the ideological criticism of the late 1960s was enough to shut the programme down. He then turns to mathematics, biology, cybernetics and epistemology for concepts sociology might borrow.

Chief among them is autopoiesis, detached from its biological origins so it can describe self-reproducing social systems, whose closure and openness condition one another and which keep human beings in their environment rather than inside them.