be considered as a single structural universe: the historical reality that takes shape in societies characterized by a codified or crystallized right, with a power organized hierarchically and justified by the law that gives it authority, with a well-defined social and economic stratification, with an economic and social organization that gives the society precise organic characteristics, with one (or multiple) religious organizations, in justification of the power expressed by such a society and in support of the religious beliefs of individuals and accepted by society as a whole. Such a structural universe, evolves in a cyclical manner, presenting two different historical phases (a mercantile phase, or “open society”, and a feudal phase or “closed society”), with characteristics so divergent that it can qualify as two different levels of civilization which, however, are never definitive, but that alternate cyclically, being able, each of the two different levels, to be considered progressive (in a partisan way, totally independent of the real value of well-being, degrees of freedom granted, equality realized and a concrete possibility to achieve further progress of the level of civilization), even by the most cultured fractions, educated and intellectually more equipped than the various societies, of both historical phases. State autonomy within institutionalism State autonomy theorists believe that the state is an entity that is impervious to external social and economic influence, and has interests of its own. "New institutionalist" writings on the state, such as the works of Theda Skocpol, suggest that state actors are to an important degree autonomous. In other words, state personnel have interests of their own, which they can and do pursue independently of (at times in conflict with) actors in society. Since the state controls the means of coercion, and given the dependence of many groups in civil society on the state for achieving any goals they may espouse, state personnel can to some extent impose their own preferences on civil society. Theories of state legitimacy States generally rely on a claim to some form of political legitimacy in order to maintain domination over their subjects. Social contract theory Various social contract theories have been proffered to establish state legitimacy and to explain state formation. Common elements in these theories are a state of nature that incentivizes people to seek out the establishment of a state. Thomas Hobbes described the state of nature as "solitary, poor, nasty, brutish, and short" (Leviathan, Chapters XIII–XIV).