Modal Realism and Coincident Objects

Imagine two objects, a lump of clay called Lumpl and a statue named Goliath, which are created and destroyed simultaneously, sharing all spatiotemporal properties. Despite their complete coincidence throughout existence, they appear to possess different properties, leading to a philosophical debate among metaphysicians. Monists argue for their identity, while pluralists deny it. Pluralists face the challenge of explaining the differences between these coincident objects, while monists must account for the modal differences if they are identical. Monists often turn to Lewisean modal realism to reject pluralism and explain the differences, claiming it offers qualitative parsimony. However, I will argue that Lewisean modal realism is not truly parsimonious and cannot be used to reject pluralism and explain the modal differences between Lumpl and Goliath due to inherent circularity in the theory.