In this talk, I will first explain why I think we cannot believe an error theory about all normative judgements. I will then argue that this makes such an error theory more likely to be true. I think it does this in three ways: it undermines objections to the theory, it makes it harder to reject the arguments for the theory, and it undermines revisionary alternatives to the theory. I will then ask whether we can say similar things about certain other versions of nihilism: nihilism about responsibility, eliminativism about propositional attitudes, and alethic nihilism.