Abstract

Leibniz once argued that scholastic substantial forms do not exist, but he later emphasized that bodies have substantial forms. This implies that he assumed that bodies have intrinsic powers to act by themselves. In order to understand the change of his metaphysics, we need to identify the resources of his motivation to introduce a new view. On the basis of Leibniz’s early works in the 1670s and 80s, this paper explores how his discovery of the law that the quantity of force, measured by mv2, is conserved, affected his development of metaphysics, and argues that the discovery actually motivated him to assume that there are enduring substantial forms in bodies, introducing an argument to establish the existence of forms on the basis of an early work. In the final section of the paper, I examine Daniel Garber’s interpretation according to which the discovery of the conservation law is largely independent of Leibniz’s rehabilitation of substantial forms.