In the first part of the thesis, I defend the moral error theory: moral judgments are uniformly false because they state irreducibly normative facts while there are no such facts. Error theorists disagree as to what we should do with our moral beliefs: some think we should keep them; others insist that we get rid of them; still others invite us to replace them with different attitudes. All agree, however, that the issue depends on a cost-benefit analysis. On my view, which I expose in the second part of the thesis, it would be best for us to replace our moral beliefs with moral make-beliefs: we should accept a moral fiction. This raises the question: "What would be the content of this fiction?” In this respect, I argue that the moral fiction should be utilitarian: it should be composed of moral principles that would maximize overall well-being.