  Interestingly, the two lines of argument are not really compatible. If one thinks that moral claims do not even purport to report facts, one cannot intelligibly hold that the facts such claims purport to report do not exist. Nonetheless, in important ways, the considerations each mobilizes might be used to support the other. For instance, someone defending an error theory might point to the ways in which moral claims are used to express or serve peoples’ emotions, attitudes, and interests, to explain why people keep arguing as they do despite there being no moral facts. And someone defending noncognitivism might point to the practical utility of talking as if there were moral facts to explain why moral claims seem to purport to report facts even though they do not.