The first wave of social systems theory is Parsons's structural functionalism, the second wave is derived from the general systems theory of the 1960s through the 1980s, and the third wave is based on the complex dynamical systems theory developed in the 1990s. This book focuses on the third wave of systems thinking in sociology. Third-wave systems theory has more potential relevance to sociology than the first two waves, and it offers theoretical concepts and methodological tools that have the potential to speak to unresolved core sociological issues. Because the third wave has not yet had much impact on the social sciences, a primary goal of this book is to demonstrate that third-wave theory addresses weaknesses of the first and second waves and to show the practical and theoretical implications for the social sciences.

First- and second-wave systems theories often discussed social emergence, but these prior treatments were overly brief and insufficiently developed; foundational questions related to emergence were not addressed. For example, both individualists and collectivists often refer to themselves as emergentists, yet their positions are theoretically incompatible (Chapter 5). Collectivists argue that although only individuals exist, collectives possess emergent properties that are irreducibly complex and thus cannot be reduced to individual properties and relations. Yet emergence has also been invoked by methodological individualists in sociology and economics. Methodological individualists accept the existence of emergent social properties but claim that such properties can be explained in terms of individuals and their relationships.