On the purpose of the contract, the theories of the social contract differ. Hobbes and Locke`s traditional contractual theories dealt with the conditions of political union. The problem was, among other things, the reasons and limitations of citizens` obligation to obey the state. In its early formulation, Rawls` parties discussed « common practices » (1958). In his subsequent opinion, Rawls accepted the objective of the agreement as principles of justice, in order to regulate the « basic structure »: in addition to defining what representatives consider the world and the results of their agreement, there must be a standard where that representative parties can assess different contractual possibilities. They must be able to organize options based on their values, whatever they may be. Rawls models the parties to the contract situation because they have only an initial value: primary assets. They choose the concept of justice they do, to the extent that they believe it will probably produce the most important goods for them and their descendants. This specification of the rating parameter is uniform in all choices and therefore allows to model the selection in the initial position as an individual`s choice. To the extent that there is evaluative diversity among representatives, more complex models of the agreement are needed (see item 3). Decisions must be made – who should be the leader, and decisions are made – how do we decide who should take the lead.
This idea that free individuals come together and mislead a number of rules is the idea behind a social contract. A central axiom that all negotiation theories use is, for example, an axiom of symmetry. This axiom says that bargain hunters will justify the same thing in the situation, that I will not be willing to give or take more than you in the same situation. This axiom seems reasonable, but it does not follow that the refusal of symmetry is in some way a denial of reason. In fact, Thomas Schelling (1959) was a former critic of the symmetry hypothesis in negotiation theory and more recently, John Thrasher (2014) argued that the symmetry hypothesis is incompatible with the traditional model of the social contract. However, symmetry is necessary to create a single solution to the problem of negotiation. A refusal of symmetry will probably lead to a rejection of singularity, at least in the axiomamatic theory of negotiation. 33. There has never been some kind of absolute justice, but only agreements that have been made in the context of a mutual relationship between men in different places, at different times, who oppose the addition or suffering of evil.
 The best way to understand Hobbes` political theory is to enter into two parts: his theory of human motivation, psychological selfishness, and his theory of social contract, based on the hypothetical state of nature. Hobbes has above all a particular theory of human nature that leads to a particular vision of morality and politics, as developed in his philosophical masterpiece Leviathan, published in 1651. The scientific revolution, with its important new discoveries, which the universe could be described and predicted in accordance with the universal laws of nature, strongly influenced Hobbes. He tried to provide a theory of human nature that would be equated with discoveries in the sciences of the inanimate universe. His psychological theory is therefore informed by the mechanism, the general opinion that everything in the universe is produced by nothing but matter in motion. According to Hobbes, this extends to human behavior. Human macro-behaviors can be well described as the effect of certain types of micro-behaviors, although some of these latter behaviors are invisible to us. Behaviours such as walking, speech, etc. are therefore created in us by other actions. And these other actions are themselves caused by the interaction of our body with other bodies, human or otherwise, which create in us certain chains of causes and effects, and which end up leading to human behavior that we can clearly observe.