 In the Fourth Part of the Logic, “On Method,” Arnauld and Nicole present an account of the distinction between analysis and synthesis that they say is taken from a manuscript of Descartes lent to them by Clerselier. What they present is a free translation of Rule Thirteen of the Rules for the Direction of the Mind. They then paraphrase the four rules given by Descartes in Part Two of the Discourse on the Method, saying that although the rules are “often difficult to follow,” yet “it is always helpful to bear them in mind, and to heed them as much as possible whenever we try to find the truth by means of reason” (Logic, 234–39). But Arnauld developed the Cartesian position on philosophical method in a distinctive way. In particular, he reshaped the notion of an idea, of a confused idea, of a clear and distinct idea, and of methodic doubt.