An epistemological argument for moral response-dependence

Perhaps the most common philosophical view about the nature of morality is non- naturalistic moral realism. According to this view, moral properties or facts or truths exist as features of the objective, mind-independent universe -- and they are, moreover, intrinsically normative and irreducible to naturalistic properties. The view seems to be at a special advantage in accounting for the objectivity and normativity of morality. There are, however, serious objections to it. I offer a new, strengthened epistemological objection to non-naturalistic moral realism by arguing that we could never rationally decide to accept our ordinary first-order moral beliefs (e.g. the belief that killing people for fun is wrong) if we were to understand them as beliefs about non-naturalistic realist normative truths. Thus, we could not maintain them in reflective equilibrium. This unacceptable skeptical outcome motivates my abandonment of non- naturalistic moral realism.;I develop an alternative metaethical theory by first examining other kinds of norms about which metaphysical and epistemological skepticism is rarely expressed. I focus on an ordinary game with a set of conventionally determined rules and argue that it can only be understood as a normative practice -- that is, as constituted by a set of norms that provide reasons and requirements to the players in virtue of their commitment to it. Further investigation yields a response-dependence biconditional which indicates how the relevant reasons and requirements are determined by people's judgments. I argue that this response-dependence biconditional both provides for a constructivist, anti-realist account of the relevant reasons and requirements, and also provides for an explanation of how we can rationally accept our most reflective beliefs about them.;My theory is extended to account for diverse kinds of reasons and requirements by showing why and how we construct different kinds of normative practices. I sketch the nature of, and some of the differences between, the normative practices that I believe account for the instrumental, epistemic, and aesthetic reasons and requirements that we are subject to. Finally, I offer a response-dependence account of morality as a cooperative normative practice by combining T.M. Scanlon's contractualist formula with a sentimentalist account of reasonable objections to candidate principles.