Abstract
Metaphysicians sometimes appeal to physics to establish claims about the fundamental nature of the world. But given the current state of inquiry in physics, where there are two most fundamental theories that are incompatible, such arguments of physics-based metaphysics are problematic. I support this line of thought by focussing on two sorts of problematic arguments, special-relativity-based arguments against presentism and big-bang-based arguments in favor of the existence of God. I am not arguing that physics-based metaphysics can’t be done; I am just arguing that extant examples of physics-based metaphysics are flawed. I close by considering various ways that future versions of physics-based metaphysics could potentially be successful.