Abstract

It’s widely accepted that we have most reason to accept theories that best fulfill the following naturalistically respectable criteria: internal consistency, consistency with the facts, and exemplification of the theoretical virtues. It’s also widely accepted that metaphysical theories are necessarily true. I argue that if you accept the aforementioned criteria, you have most reason to reject that metaphysical theories are necessarily true. By applying the criteria to worlds that are all prima facie possible, I show that contingent local matters of particular fact partly determine which theory of composition we should accept at a world. For instance, I argue that when we apply the criteria to our world, we should accept Mereological Nihilism. Furthermore, even if you think that the worlds I mention, such as gunky worlds, are impossible, you should still reject the brute principle that metaphysical theories are necessarily true. Instead, you should only accept that a theory of composition is necessarily true if contingent local matters of particular fact at possible worlds cannot tell in favor of one theory of composition over another.