About a week ago, I finished the reviews of a couple of excellent books which deal with moral skepticism. In this post, I'll refer to the first of them: Walter Sinnott-Armstrong, Moral Skepticisms (Oxford University Press, 2006). The book examines the different types of moral skepticism and assesses the force of the main replies to moral skeptical arguments. Although Sinnott-Armstrong's own position is skeptical, it is not a form of moral nihilism or ontological moral skepticism, which are probably the most common types of moral skepticism adopted in contemporary philosophy. Rather, his is a ‘moderate moral skepticism’: he rejects that our moral beliefs are justified absolutely or without qualification, but accepts that they may be partially justified. The key lies in the notion of ‘contrast class’, which is a set of propositions which are incompatible with each other, so that if one is justified in believing a proposition P out of a contrast class C, it is because one has grounds that rule out all the other propositions of C but not P. A belief may be, at the same time, justified out of one contrast class, but not out of another. Thus, even though moral beliefs cannot be justified out of the contrast class which includes moral nihilism as a member – because this position cannot be refuted without begging the question – they can sometimes be justified out of limited contrast classes which do not include moral nihilism or other extreme positions. The question that naturally arises is which contrast class is really relevant. Sinnott-Armstrong maintains that this question is impossible to answer, so he suspends judgment about which contrast class, if any, is really relevant, even in a particular context. This is why he describes himself as a meta-skeptic about real relevance or as a ‘classy Pyrrhonist’. In sum, moral beliefs can be justified or unjustified, not absolutely, but solely relative to different contrast classes. Given that Sinnott-Armstrong suspends judgment about real relevance, it seems to me that his position is a sort of epistemic relativism about moral beliefs. Indeed, the only epistemic justification available is that which is relative to contrast classes, so that the truth-value of the propositions that express our moral beliefs is entirely relative to them. My objections have to do (i) with whether his position can be legitimately labeled 'Pyrrhonian', and (ii) with the fact that he is an 'insulator', since he thinks that skepticism cannot affect our substantive moral beliefs.