Substantial Simplicity in Leibniz

This article attempts to determine how Leibniz might safeguard the simplicity of an individual substance (singular) while also retaining the view that causal powers (plural) are constitutive of said individual substance. I shall argue that causal powers are not to be understood as veritable parts of a substance in so far as such an account would render substances as unnecessarily complex. Instead, my proposal is that sense can be made of Leibniz’s metaphysical picture by appeal to truthmakers. In order to develop my argument I critically examine (a) Leibniz’s revival of the scholastic notion of substantial form, (b) his theory of accidents, and (c) his account of metaphysical predication, and argue that an application of truthmaker theory can satisfy each in accordance with his simplicity requirement on individual substances