Non-mereological pluralistic supersubstantivalism: an alternative perspective on the matter/spacetime relationship

In both the historical and contemporary literature on the metaphysics of space (and, more recently, spacetime), a core dispute is that between relationism and substantivalism. One version of the latter is supersubstantivalism, according to which space (or, again, spacetime) is the only kind of substance, such that what we think of as individual material objects (electrons, quarks, etc.) are actually just parts of spacetime which instantiate certain properties. If those parts are ontologically dependent on spacetime as a whole, then we arrive at an ontology with only a single genuinely independent substance, namely the entire spacetime manifold. This is monist supersubstantivalism. A view on which the parts of spacetime are ontologically prior to the whole has been called pluralistic supersubstantivalism. As currently formulated, supersubstantivalism (in either its monist or pluralistic forms) carries significant advantages and encounters major difficulties. I argue that some of the latter motivate an alternative formulation, non-mereological pluralistic supersubstantivalism, according to which spacetime is a real substance, but what we think of as material objects are also real substances, irreducible to and numerically distinct from that larger spacetime manifold and any of its parts. Yet, the underlying nature of those material objects is ultimately the same type as that of spacetime: at bottom, a particle is just a smaller quantity of spacetime embedded in or contained by or co-located with the larger whole that we would normally think of as ‘spacetime,’ capable both of genuine movement within/across the larger spacetime manifold and (at least in principle) independent existence from it.