 If successful, this argument tells us something useful about moral – and also, by similar reasoning, normative – concepts: that they cannot be reduced to natural ones. But it does not automatically tell us anything about moral metaphysics. It is entirely possible that while the concept &lt;bad&gt; cannot be reduced to the concept &lt;painful&gt;, the property of badness (if there is such a property) can be reduced to the property of painfulness. Roughly speaking, there can be conceptual gaps even where there are no metaphysical gaps: water might be distinct from H2O at the conceptual level even if water is metaphysically identical to H2O. Some metaethical naturalists have argued for an analogous claim in the ethical domain (see Boyd 1988).