The conception of René Descartes as the arch-rationalist has been sufficiently exploded in recent literature; however, there is still a large lacuna in our understanding of how empirical research and experimentation fits within his philosophy. My dissertation is directed at addressing just this problem. I contend that Descartes’ famed method is not a singular monolith but instead two interdependent methods: one directed at metaphysical and epistemological truth, while the other directed at empirical questions and contingent facts of the world. I claim there is evidence for this position not only in his actual scientific practice, but also in the rhetorical structure of the Discourse on Method and the Principles of Philosophy. In exploring the empirical side of Descartes’ method, I show how his unusual system produces a system of experiment designed to serve both as a discovery and verification tool at the same time. As a further application of my interpretation, I argue that the Passions of the Soul and Descartes’ ethical theory expressed in his correspondence must also be seen as part of his two-fold methodology. Instead of attempting to cast Descartes as a virtue ethicist or deontologist, as is normally done, I emphasize that Descartes’ ethics is centered on the mind-body union, and therefore, includes an empirical element as well. The end result is an ethics that requires a detailed study of mechanics, anatomy, physics, as well as medicine. Lastly, I show how this methodology can help us understand the works of some of his early followers: Claude Gadroys and Jacques Rohault. Both of these philosophers not only serve to ground my interpretation, but also to highlight aspects of Cartesian that have often been passed over. I show how the experimentalism of Jacques Rohault goes beyond the epistemological boundaries set up by Descartes, as signifies a new direction that will ultimately eclipse the Cartesian school of thought. In the case of Claude Gadroys, I present a concrete example of the exploitation of the over generality of Cartesian principles. In so doing, I show that while Descartes’ experimentalism was intended to rule out the possibility of occult causes, he in fact created a system that allowed for them, only under a different guise.