We usually divide the history of the philosophical world into periods—Ancient, Medieval, and Modern—and teach Modern Philosophy beginning with René Descartes and ending with Immanuel Kant. The reason for this typically involves a view of Modern Philosophy consisting of two distinct camps: Continental Rationalists (Descartes, Baruch Spinoza, and Gottfried Wilhelm Leibniz), who it is said emphasize reason at the expense of the senses, and British Empiricists (John Locke, George Berkeley, and David Hume), who accentuate the senses after rejecting innate ideas. As we teach him, Descartes, “the father of modem philosophy,” breaks with scholasticism and Medieval Philosophy by calling all beliefs into doubt (especially those based on the senses); he seeks to ground all knowledge on the innate ideas he discovers within himself and then reflects upon, beginning with the one he has of himself as a thinking thing (in the cogito). The other rationalists follow, trying to come to a clear and distinct conception of their own ideas and to establish knowledge about the world with the same kind of absolute certainty and necessity attainable in mathematics. Locke and the empiricists, in turn, break with the rationalists by rejecting innate ideas, claiming instead that the content of all of our mental states stems from experience, whether through sensation or reflection. The proper task of philosophy becomes the one of analyzing the meaning of the ideas we receive from sensation and reflection and determining what we can come to know about the world on that basis. Given this picture, Kant is then presented as the culminating figure of modem philosophy because of his attempt to synthesize the rationalist and empiricist traditions.
While there is some truth in the simple schema we teach, its greatest deficiency is that it misses too much of the real Descartes. In the 17th century Descartes was known as well, if not more, for his achievements in mathematics, physics, cosmology, physiology, philosophical psychology, and so forth. It would be difficult to overstate the influence of Descartes over practically every aspect of 17th-century thought, even over such far-flung subjects as geology and medicine. Moreover, the followers of Descartes were extraordinarily committed to their master’s thought; and anti-Cartesians were just as determined to condemn Cartesianism, to refute it, to be rid of it in any way possible. This strain between the new generation of Cartesian students and the scholastic old-timers is clearly palpable in the description of the Cartesians’ behavior, in one of the entries from François Babin’s Journal, written at the College of Angers in the 1670s and taking the point of view of the anti-Cartesians:
Young people are no longer taught anything other than to rid themselves of their childhood prejudices and to doubt all things—including whether they themselves exist in the world. They are taught that the soul is a substance whose essence is always to think something; that children think from the time they are in their mothers’ bellies, and that when they grow up they have less need of instructors who would teach them what they have never known than of coaches who would have them recall in their minds the ancient ideas of all things, which were created with them. It is no longer fashionable to believe that fire is hot, that marble is hard, that animate bodies sense pain. These truths are too ancient for those who love novelty. . . . They tell us that something does not stop being true in philosophy even though faith and the Catholic religion teach us the contrary—as if the Christian and the philosopher could have been two distinct things. Their boldness is so criminal that it attacks God’s power, enclosing him within the limits and the sphere of things he has made, as if creating from nothing would have exhausted his omnipotence. Their doctrine is yet more harmful to sovereigns and monarchs, and tends toward the reversal of the political and civil state.
The tension broke into open intellectual warfare. Cartesians lost many battles: some Cartesian priests were corrected and disciplined by their superior; a few Cartesian professors were expelled from their teaching positions. But they ultimately won the war. Perhaps because of the intense struggle, however, the 17th century was a period rich in debate and remarkable in philosophical doctrine. We hope to be able to impart the flavor of these debates, that is, to say something about the people taking part in them and the doctrines they supported or opposed.