Reply to Cees Leijenhorst’s Review of Leibniz’s Metaphysics

Abstract

I n his thoughtful and generous review of my book, Leibniz's Metaphysics: Its Origins and Development, Cees Leijenhorst accepts many of its most radical conclusions: that Leibniz's metaphysics evolved out of an attempt to combine ideas gathered from the great philosophers of the past and to do so in a manner that would solve the theological, legal, and philosophical questions that most concerned him; that although Leibniz's notion of substance developed out of his interpretation of the philosophy of Aristotle, his conception of the relation between God and creatures (and therefore his account of universal harmony) has its roots in the Platonism that he learned as a young man in Leipzig and Jena; that the views constituting the core doctrines of the mature philosophy (including a version of preestablished harmony) were conceived by the time Leibniz went to Paris in early 1672; and that Leibniz rejects the reality of passive extended matter and embraces his own version of idealism as early as 1671. I am tempted to respond with a loud rodeo yell and end it at that. But because the few points on which Leijenhorst and I disagree (however slightly) concern some of the most severe problems that face the early modern historian, I am eager to take the opportunity to discuss these problems here. A major part of Leibniz's Metaphysics: Its Origins and Development is given over to the Platonist and Aristotelian assumptions that Leibniz learned as a young man and then used as the raw materials for his philosophy. I was motivated to distinguish between Aristotelianism and Platonism in the way that I did because Leibniz and his teachers did. But any such distinction is problematic. Appropriately, Leijenhorst worries about the fact that Mercer's book appears to use the labels 'Platonism' and 'Aristotelianism' in a rather essentialist way. To distinguish between Aristotelianism and Platonism, especially in the early modern period, is problematic in several ways. Already in late antiquity, followers of Plato and Aristotle assumed that these philosophies were in fundamental agreement. Important commentators like Porphyry (c.232-c.306) proposed a Platonism that was thoroughly mixed with Aristotelianism. This sort of Aristotelianized Platonism formed the intellectual background to medieval Europe, and informed the theological and doctrinal commitments of the early Christian church. When Renaissance and early modern thinkers turn to Augustine, they are