  Psillos (2001) argues that OSR is not ‘worked out’ as a metaphysics, and that a strong burden of proof is on those who would abandon traditional metaphysics (see also Chakravartty (2004) and Morganti (2011). However, it is far from clear that OSR's rivals are ‘worked out’ in any sense that OSR isn't. There in no general agreement among philosophers that any of the metaphysical theories of, say, universals is adequate, and arguably metaphysical categories inherited from the ancient Greeks are not appropriate for contemporary science. Naturalists argue that we should reject metaphysical doctrines if they are not supported by science. Michael Esfeld (2004, 614–616) argues against any gap between epistemology and metaphysics. Similarly Ladyman and Ross (2007) argue for a kind of verificationism in metaphysics.