The Problem of Meriological Sums

Anti-realists argue that there can be two or more complete theories of the world which are empirically equivalent. For example, theories of spacetime can be formulated in one or two mathematically equivalent ways. Anti-realists claim that the world itself cannot tell us which description is correct. And if this is true, then it seems that the world has a different structure or basic ontology depending on which conceptual schemes we choose.