Functionalism
Main article: Functionalism in international relationsFunctionalism is a theory of international relations that arose principally from the experience of European integration. Rather than the self-interest that realists see as a motivating factor, functionalists focus on common interests shared by states. Integration develops its own internal dynamic: as states integrate in limited functional or technical areas, they increasingly find that momentum for further rounds of integration in related areas. This "invisible hand" of integration phenomenon is termed "spill-over." Although integration can be resisted, it becomes harder to stop integration's reach as it progresses. This usage, and the usage in functionalism in international relations, is the less common meaning of functionalism.
More commonly, however, functionalism is an argument that explains phenomena as functions of a system rather than an actor or actors. Immanuel Wallerstein employed a functionalist theory when he argued that the Westphalian international political system arose to secure and protect the developing international capitalist system. His theory is called "functionalist" because it says that an event was a function of the preferences of a system and not the preferences of an agent. Functionalism is different from structural or realist arguments in that while both look to broader, structural causes, realists (and structuralists more broadly) say that the structure gives incentives to agents, while functionalists attribute causal power to the system itself, bypassing agents entirely.
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