He used that approach to write a religious text, the Meditations on First Philosophy.
This man downplayed differences between Protestant and Catholic concepts of God in his Letter to Voetius. The four rules he used in all of his investigative work included dividing problems into simple parts and accepting only the self-evident as true; he codified his approach in Rules for the Direction of the Mind and Discourse on Method. He used that approach to write a religious text, the Meditations on First Philosophy. For 10 points, name this skeptical philosopher who started his investigations by declaring "Je pense, donc je suis" or "I think, therefore I am."
This man downplayed differences between Protestant and Catholic concepts of God in his Letter to Voetius.
Rene Descartes