Antoine Arnauld was the man in the 1600’s; everyone though he was the Frenchman of the time. He was theologian (who wasn’t in 1630?) who was able to go toe-to-toe, and did, with Descartes, Malebranch, and Leibnix (all thinkers I would cower before). In the midst of everyone wanting to take a shot at Descartes after his revolutionary (and somewhat unpopular) answer to the mind-body problem, Arnauld, despite his many philosophical differences, had his back. Arnauld wrote a defense of Descartes and agreed heavy with his dualism. Arnauld argued and debated all his life and spend his last fifteen years in a self-imposed exile where he continued to debate Malebranche and Leibniz from exile. If you are like me and stuck on the topic of free-will, Arnauld wrote extensively on this and went somewhat back and forth, and you should read The Art of Thinking and On True and False Ideas.