 A competitive market is not a legal system, even though people adjust their behaviour in response to relative prices and the whole constitutes a form of social order. Neither was the system of mutual nuclear deterrence, though it guided behaviour and generated norms that regulated the Cold War. Many philosophers and social scientists agree that a social order is a legal system only if it has effective authority. An effective (or de facto) authority may not be justified, but it does stand in a special relation to justified (de jure) authority. Justified authority is what effective authorities claim, or what they are generally recognized to have.