The Duhem-Quine thesis famously holds that a single hypothesis cannot be confirmed or disconfirmed in isolation, but instead only in conjunction with other background hypotheses. This article argues that this has important and underappreciated implications for metaethics. Section 1 argues that if one begins metaethics firmly wedded to a naturalistic worldview—due (e.g.) to methodological/epistemic considerations—then normativity will appear to be reducible to a set of social-psycho-semantic behaviors that I call the ‘normative stance.’ Contra Hume and Bedke (2012), I argue that the normative stance provides semantically-grounded entailments from natural truths to normative truths, reducing the latter to the former. Specifically, the normative stance explains the truth-conditions, truth-values, and truth-makers of normative propositions in terms of socially grounded cognitive-behavioral rules and other natural facts, thus explaining how there can be bona fide normative facts and properties in a wholly naturalistic world. I then show that the normative stance explains the apparent stance-independence and non-naturalness of normative reasons, intrinsic value, and categoricity of moral reasons as ‘user-illusions’ generated by people having strong psycho-social propensities—rooted in evolution and social cooperation—to take these normative stances. Section 2 then argues that while the normative stance may appear to naturalists to successfully explain normativity, it will not appeal to those who come to metaethics with different background commitments. I conclude that naturalists should take the normative stance to be a promising metaethical theory of normativity, and that whether it is a true theory of normativity is something that can only be ascertained by determining which background hypotheses—naturalistic or otherwise—we should have when doing metaethics.