One version of moral error theory maintains that the central problem with morality is an ontological commitment to irreducible normativity. This paper argues that this version of error theory ultimately depends on an appeal to Ockham’s Razor, and that Ockham’s Razor should not be applied to irreducible normativity. This is because the appeal to Ockham’s Razor always contains an intractable element of epistemic circularity; and if this circularity is not vicious, we can construct a sound argument for the existence of (...) irreducibly normative truths that contains a similar kind of epistemic circularity. This argument is a version of Pascal’s Wager which I call “Parfit’s Wager,” because it is based on a passage from Derek Parfit’s On What Matters. It states that, if we believe that there are some irreducibly normative truths, we are more likely to be believing what we ought to believe compared to not believing that there are such truths, and that this indicates that we ought rationally to believe that there are such truths, justifying the ontological commitment to irreducible normativity in the process. (shrink)