The German sociologist Niklas Luhmann has provided one of the most elaborate theories of society available, as well as numerous works on specific aspects of society. Commonly labeled as “systems theory,” this is but a shorthand description of Luhmann’s theory. In fact, the theory rests on at least three main theoretical pillars. In addition to systems theory, a theory of social evolution and a theory of social differentiation play important roles. The present article introduces these three pillars and describes Luhmann’s theory of politics in this context. It outlines the crucial difference between a theory of politics as part of a theory of society on the one hand, and political theory as a reflective theory within the political system on the other hand. More specifically, it introduces Luhmann’s accounts of the notions of “political power,” “differentiation,” “the state,” “political steering,” and “the self-description of the political system.” The contribution concludes with some observations on the fact that Luhmann’s theory has tended to overlook the dimension of international politics, but that his theory provides opportunities to account for it in innovative ways.
Rational choice theory may seem like a separate theoretical approach with its own forbidding mathematics. However, the central assumptions of rational choice theory are very similar to those in mainstream political behavior and even interpretive sociology. Indeed, many of the statistical methods used in empirical political behavior assume axiomatic models of voter choice. When we consider individual voting behavior, the contribution of rational choice has been to formalize what empirical political scientists do anyway, and provide some new tools. However, it is when we consider collective voting choice—what elections mean and what kind of policy outcomes result—that rational choice leads to new, counterintuitive insights. Rational choice also has a normative dimension. Without voter rationality the traditional understanding of democracy as popular choice makes little sense.