A Mereological Study of Lowe’s Constituting Parthood Theory

Abstract Late Lowe’s metaphysics of material objects is an interesting multi-thingist theory that still attracts interest from various authors. The core idea is that ifxmaterially constitutesy, thexis a proper part ofy. I discuss some mereological issues that arise from the approach and propose a revision of the mereology associated. Particularly, I examine the tenability of a number of supplementation principles and conclude that just one may serve the theory adequately. Still, the endorsement of such a principle does not come for free. Successively, I address the derivability of an important extensionality theorem and conclude that the theorem must be taken as an axiom in the mereology at stake. Lastly, I discuss two notable definitions of mereological fusions to assess which one best suits the present theory. The result is that authors sharing Lowe’s multi-thingist conception of material objects can still enjoy a moderately strong mereology.