This chapter argues that “the Hobbesian hypothesis” (the claim that the Lockean proviso is fulfilled: everyone is better off in a state society with a private property system than they could reasonably expect to be in any society without either of those institutions) plays a large role in contemporary justifications of the state and/or the property rights system. The search turns up few attempts to justify existing states or property rights systems without some version of the hypothesis. Theorists asserting it as an obvious truth in need of little or no supporting evidence include David Gauthier, Jean Hampton, James Buchanan, Gregory S. Kavka, George Klosko, Dudley Knowles, Christopher Heath Wellman, Robert Nozick, Jan Narveson, and many others. Critics include Alan Ryan, Carole Pateman, Charles Mills, Patricia Williams, and others. Yet all this disagreement has produce very little debate or interest in an empirical investigation of the hypothesis.