Moral error theories claim that (i) moral utterances express moral beliefs, that (ii) moral beliefs ascribe moral properties, and that (iii) moral properties are not instantiated. Thus, according to these views, there seems to be conclusive evidence against the truth of our ordinary moral beliefs. Furthermore, many error theorists claim that, even if we accepted moral error theory, we could still in principle keep our first-order moral beliefs. This chapter argues that this last claim makes many popular versions of the moral error theory incompatible with the standard philosophical accounts of beliefs. Functionalism, normative theories of beliefs, representationalism, and interpretationalism all entail that being sensitive to thoughts about evidence is a constitutive feature of beliefs. Given that many moral error theorists deny that moral beliefs have this quality, their views are in a direct conflict with the most popular views about the nature of beliefs.