Reasons for the Method in Descartes’ Discours

In the practical philosophy of the Discours de la Méthode, before the theoretical metaphysics of Part Four and the Meditationes, Descartes gives us an inductive argument that his method, the procedure and cognitive psychology, is veracious at its inception. His evidence, akin to his Scholastic predecessors, is God, a maximally perfect being, established an ontological foundation for knowledge such that reason and nature are isomorphic. Further, the method, he tells us, is a functional definition of human reason; that is, like other rationalists during this period, he holds the structure of reason maps onto the world. The evidence for this thesis is given in what I call the groundwork to Descartes’ philosophical system, essentially the first half of the Discours, where, through a series of examples in the preamble of Part Two, he, step-by-step, ascends from the perfection of artifacts through the imposition of reason (the Architect Example) to the perfection of a constituent’s use of her cognitive faculties (the Wise-Lawgiver Example), to God perfecting and ordering reality (the Divine Artificer Example). Finally, he descends, establishing the structure of human reason, which undergirds and entails the procedure of the method (the Laws of Sparta Example).