In international relations theory, anarchy refers to the idea that the world lacks any supreme authority or sovereignty). In an anarchic state, there is no hierarchically superior, coercive power that can resolve disputes, enforce law, or order the system of international politics). However, international relations generally does not understand "anarchy" as signifying a world in chaos, disorder, or conflict; rather, it is possible for ordered relations between states to be maintained in an anarchic international system). Anarchy provides foundations for realist, neorealist, neoliberal, and constructivist paradigms of international relations). Schools of thought in international relations theory agree that the world system is anarchic, but they differ in their explanations of how states should, and do, deal with this problem. Anarchy imposes incentives and constraints on states, and it is a self-help system, where each sovereign unit is responsible for its own security within a competitive, often ruthless, Hobbesian domain. The absence of a common superior in an interaction domain characterizes anarchy in international relations.