Immaterial Mechanism in the Mature Leibniz

Leibniz standardly associates “mechanism” with extended material bodies and their aggregates. In this paper, I identify and analyze a further distinct sense of “mechanism” in Leibniz that extends, by analogy, beyond the domain of material bodies and applies to the operations of immaterial substances such as the monads that serve, for Leibniz, as the metaphysical foundations of physical reality. I argue that in this sense, Leibniz understands “mechanism” as an intelligible process that is capable of providing a sufficient reason for a series of changes. I then apply these findings to enrich our understanding of Leibniz’s well-known mill argument in Monadology ¶17: although material machines and mechanisms cannot produce perceptions, the perceptual activity of immaterial monads is to be understood as “mechanical” according to this analogical sense.