explicitly agreed to be constrained if, as a private individual, he did not respect his own will as formulated in the general will. Because laws represent the restraint of "natural liberty", they represent the leap made from humans in the state of nature into civil society. In this sense, the law is a civilizing force. Therefore Rousseau believed that the laws that govern a people help to mould their character. Rousseau also analyses the social contract in terms of risk management, thus suggesting the origins of the state as a form of mutual insurance. Pierre-Joseph Proudhon's individualist social contract (1851) While Rousseau's social contract is based on popular sovereignty and not on individual sovereignty, there are other theories espoused by individualists, libertarians, and anarchists that do not involve agreeing to anything more than negative rights and creates only a limited state, if any. Pierre-Joseph Proudhon (1809–1865) advocated a conception of social contract that did not involve an individual surrendering sovereignty to others. According to him, the social contract was not between individuals and the state, but rather among individuals who refrain from coercing or governing each other, each one maintaining complete sovereignty upon him- or herself: John Rawls' Theory of Justice (1971) Building on the work of Immanuel Kant with its presumption of limits on the state, John Rawls (1921–2002), in A Theory of Justice (1971), proposed a contractarian approach whereby rational people in a hypothetical "original position" would set aside their individual preferences and capacities under a "veil of ignorance" and agree to certain general principles of justice and legal organization. This idea is also used as a game-theoretical formalization of the notion of fairness. David Gauthier's Morals By Agreement (1986) David Gauthier "neo-Hobbesian" theory argues that cooperation between two independent and self-interested parties is indeed possible, especially when it comes to understanding morality and politics. Gauthier notably points out the advantages of cooperation between two parties when it comes to the challenge of the prisoner's dilemma. He proposes that, if two parties were to stick to the original agreed-upon arrangement and morals outlined by the contract, they would both experience an optimal result. In his model for the social contract, factors including trust, rationality, and self-interest keep each party honest and dissuade them from breaking the rules. Philip Pettit's Republicanism (1997) Philip Pettit (b. 1945) has argued, in Republicanism: A Theory of Freedom and Government (1997), that the