MEREOLOGICAL NIHILISM AND SIMPLE SUBSTANCE IN LEIBNIZ

Leibniz famously argues that there must be sim-ple substances, since there are composites, and a composite is nothing but a collection of simples. I reconstruct Leibniz's argument, showing that it relies on a commitment to mereological nihilism (i.e., the view that composites can-not be true beings). I show further that Leibniz endorses mereological nihilism as early as the 1680s and offers both direct and indirect support for this commitment: indirect support via the notion of unity and direct support via the notion of persistence. I then assess the alignment of Leib-niz's mereological nihilism with his other commitments during the 1680s, including his potential commitment to corporeal substances. I argue that any viable interpretation of Leibniz's commitment to corporeal substances is compatible with mereological nihilism, which provides a new perspective both on Leibniz's developing theory of substance and on his mature theory of simple substance.