Rousseau has two different social contract theories. The first is found in his essay Discourse on the Origin and Foundations of Inequality Among Men, commonly referred to as the Second Discourse, and is a report on the moral and political evolution of men over time, from a state of nature to modern society. As such, it contains his naturalized presentation of the social contract, which he considers very problematic. The second is its normative or idealized theory of the social contract and must provide the means to alleviate the problems that modern society has created for us, as stated in the social contract. The application of laws, including criminal law, is therefore not a restriction of individual freedom: the individual, as a citizen, has expressly agreed to be limited if he does not respect, as an individual, his own will, as formulated in the general will. Because laws are the limits of civil liberty, they represent the leap from man in its natural state to civil society. In this sense, the law is a force of civilization, and that is why Rousseau believed that the laws that govern a people helped to forge its character. The social contract theories of Hobbes, Locke, and Rousseau have all pointed out that the justification of the state depends on everyone agreeing in one way or another. Relying on consent, social contract theory seemed to adopt a voluntarist conception of political justice and commitment: what is considered “justice” from “commitment” depends on what people agree with, regardless of their agreement. It is only in Kant (1797) that it becomes clear that the approval of a vision of the social contract is not fundamental: we have the duty to agree on the idea of the “initial contract”.
The revival of Rawls` social contract theory in A Theory of Justice did not justify commitments based on approval, although the apparatus of an “initial agreement” was maintained as a way to solve the problem of justification. While the question of public justification is at the center of concerns, it is clear that the problem of justification in the form of a problem of deliberalization or negotiation is a heuristic: the real question is “the problem of justification” – what principles can be justified for all citizens or reasonable persons. In Plato`s best-known dialogue, the Republic, the theory of the social contract is again represented, but this time less favorable. In Book II, Glaucon offers a candidate for an answer to the question “What is justice?” by constituting a social explanation of the very essence of justice. What men want most is to be able to commit injustices against others without fear of reprisals, and what they want to avoid most is to be unfairly treated by others without being able, in return, to do injustice. Justice, he says, is the conventional result of the laws and covenants people make to avoid these extremes. Since they are not able to commit unpunished injustices (as those who wear the Gyges ring would do) and for fear of being victims themselves, men decide that it is in their interest to submit to the Convention of Justice.