 cognitivism vs. non-cognitivism, moral |  dependence, ontological |  fictionalism |  fictionalism: modal |  grounding, metaphysical |  intentionality |  Lewis, David: metaphysics |  meaning, theories of |  metaethics |  modality: epistemology of |  moral anti-realism |  moral realism |  nominalism: in metaphysics |  Platonism: in metaphysics |  possible worlds |  realism: challenges to metaphysical |  relativism |  structural realism |  truth 