What is Method?

As Timothy Reiss pointed out, in the Discours de la Méthode Descartes includes the description of two methods. The first is given in the second part of the treatise, and consists of four rules (Descartes 1637a, p. 120; AT 6, pp. 18–19). According to Reiss, however, the Discours contains also a second method, which Descartes introduces in the sixth part of the treatise, where he speaks about his manuscript (Le Monde) and indicates the reasons why he decided not to publish it. (Descartes 1637a, pp. 143–144; AT 6, pp. 63–64). To these two expositions of method we may add a third, contained in the first pages of La Géométrie (Descartes 1937b, p. 6; AT 6, p. 372). Since La Géométrie was published as an appendix to the Discours, we can say that in 1637 Descartes published three variants of his method. The first variant (from the second part of the Discours) we will call the epistemic method; the second variant (from the sixth part of the Discours) we will call the method of reduction, and the third (from La Géométrie). My aim is to explain the relations among these three formulations of Descartes' method.