Moral error theory: a cognitivist realist defence

This dissertation argues that moral error theory is the most plausible metaethical theory if we assume the truth of cognitivism about moral judgments and the moral statements that express them. According to moral error theory, various moral statements carry a non-negotiable commitment to a robust kind of categorical moral normativity, which means that this commitment cannot be denied on pains of changing the subject. Unfortunately, there is no such robust categorical moral normativity, at least not in the actual world. This entails that these moral statements are always untrue, or ‘in error’.
In arguing for moral error theory, the thesis first argues that the standard argumentative strategy for establishing moral discourse’s non-negotiable commitment—viz., forging a relation of conceptual entailment between moral statements and the statement that there exists robust categorical moral normativity—is highly problematic. It also argues that forging a presupposition relation can work, but that error theorists are best advised to pursue a completely new strategy, which uses a relation of metaphysical entailment. The dissertation then argues that moral discourse metaphysically entails robust moral categorical normativity and proceeds to present a new argument against its existence. According to this argument, various sorts of hypothetical and categorical normativity exist because these can be grounded in a naturalistically respectable metaphysic; unfortunately, categorical moral normativity cannot be so grounded.
Finally, the dissertation explores an often ignored answer to the following question: what (prudentially) should we with our error-riddled moral discourse? I argue for revolutionary cognitivism. This is the view that we should continue to use moral language and fully believe what we say but that what we say should be purged of its error. We should revolutionize our moral thought and start to conceive of morality’s normativity in a less robust way than we currently do.