Abstract

In this paper I address a structurally similar tension between phenomenalism and realism about matter in Leibniz and Kant. In both philosophers, some texts suggest a starkly phenomenalist view of the ontological status of matter, while other texts suggest a more robust realism. In the first part of the paper I address a recent paper by Don Rutherford that argues that Leibniz is more of a realist than previous commentators have allowed. I argue that Rutherford fails to show that Leibniz is any less an idealist than his main target, Robert Merrihew Adams, does. I distinguish various kinds of idealism about bodies that Leibniz might have held, and attempt to determine which package of views represents his considered view. In the second part of the paper I situate Kant’s idealism within the same coordinates. I argue that, abstracting from deep differences in their metaphysics and epistemology, Kant and Leibniz have structurally very similar views on the ontological status of matter and bodies. I conclude that the key to understanding the realist strand in their ontology of matter is understanding the way in which, for both thinkers, the forces in bodies are appearances of forces of more fundamental entities, either monads or things in themselves.