Jürgen Habermas has been called one of the two greatest sociologists in the world today; the other is the late Pierre Bourdieu (1930-2002). His theory about the life-world and the two systems is a sophisticated social model, archetype, or construct by which to understand and criticize the present late-stage of capitalistic society today.
To oversimplify what is a very comprehensive and complex theory: Habermas argues that the life-world is based on communication, agreement, and consensus. The economic and political systems require instrumental rationality for the sake of control. His theory posits situations embedded in broader “horizons” that are in turn grounded in the life-world.
No matter whether one starts with George Herbert Mead (1863-1931) from basic concepts of social interaction or with Emil Durkheim (1858-1917) from basic concepts of collective representation, in either case, society can is conceived from the perspective of acting subjects as the life-world of a social group. In contrast, from the observer’s perspective of someone not involved, society can be conceived only as a system of actions such that each action has a functional significance according to its contribution to the maintenance of the system.