 Theorists such as Hedley Bull have postulated an international society in which various actors communicate and recognize common rules, institutions, and interests.Liberals also view the international system as anarchic since there is no single overarching international authority and each individual state is left to act in its own self-interest.Liberalism is historically rooted in the liberal philosophical traditions associated with Adam Smith and Immanuel Kant that posit that human nature is basically good and that individual self-interest can be harnessed by society to promote aggregate social welfare.