ABSTRACT
What makes a complex system change? In the common view of complexity theorists, change is natural. Then, the question is not why systems change, but how they do. The task of complexity theorists is to describe the patterns and mechanisms of change. There is no unifi ed view of system dynamics among complexity theorist, but one can fi nd four distinguishable models of change in the literature: self-organized criticality, dissipative structures, self-referentiality, and coevolution. In this chapter I fi rst describe these four models and then discuss the applications of dissipative structures and coevolution models in the public policy literature. I also make fi ve propositions for future applications of these change models in policy studies.
