ABSTRACT
This chapter coruscates the role of the agent in evolutionary change. P. B. Roscoe adds to practice theory the powerful idea that the political practices of agents are the major motivating factor of political evolution. For Roscoe, political evolution is characterized by the increased centralization of agents' political power and the increased nucleation and density of the population of political communities with which the agents are affiliated. In practice theory, political evolution is an epiphenomenon of the evolution of politics and is revealed in the practices of episodic leaders in nomadic hunting and gathering societies. The evolution of politics suggests that leaders, whether they be episodic, big men, chiefs, or heads of state relative to the structure and size of their political communities, are abundant commodities in the political marketplace. Episodic leaders can begin to reap political advantage, that is, power, as a result of altering the relationship of bands only where the environmental potential for the transition permits.
