The goal of this article is to present contractualism as a method and as a result of the systematizing of other methods for constructing knowledge. While classical contractualism takes its paradigms from the geometric and mechanical models of Galileo's physics and from Descartes - particularly, the latter's model of rational choice - Rawlsian contractualism takes its paradigm from several micro-economic paradigms, and that of general equilibrium in particular. The contractualist method of the 17th Century has making politics and Law into a scientific discipline as its project, considering that, during this epoch: (i) the prevailing model of knowledge is the geometric one and knowledge is definite knowledge; (ii) the prevailing model of the individual sees the latter as rational and moved by self-interest; (iii) it entails a theory of rational human action and decision-making. Therefore, in order to make the project of turning politics and Law into science more viable, contractualism is not interpreted here substantively but instrumentally, as a method to access the bases of the political world. The contractualist method pursues a combination of the scientific model of knowledge of efficient causes and their relationship with effects, with the model of knowledge of ultimate causes as the study of ends or of the functional characteristics of things. In order to interpret contractualism as a method, we accept the new model of the relationship between knowledge and technology that has been elaborated by modern science and which maintains that knowledge of nature is a knowledge of conquest and domination that is capable of producing technological mechanisms for intervening in nature, with the goal of uncovering and manipulating causes in order to obtain the desired effects.
classical contractualist method; politics and Law as science; geometric model; rational choice model; problem solving method