An Outline of an Argument for Robust Metanormative Realism

This paper outlines a positive argument for robust metanormative realism: the view, somewhat roughly, that there are non-natural, irreducibly normative truths, that when successful in our normative inquiries we discover rather than create or construct. My argument proceeds by analogy with indispensability arguments in the philosophy of mathematics, and, more generally, inferences to the best explanation. I argue that irreducibly normative truths are indispensable, though not explanatorily indispensable. Rather, they are 'deliberatively' indispensable. And I argue that deliberative indispensability is just as respectable as explanatory indispensability, in that it too can ground ontological commitment.