The error in moral discourse and what to do about it

Moral error theory is the thesis that statements attributing moral properties to objects are always untrue. In my thesis I have two aims: to argue for error theory and defend it from a number of objections (chapters 1 and 2); and to consider whether and how we should go on with moral discourse, if we come to accept error theory (chapters 3 and 4). In the first chapter I argue for error theory by defending a number of metaethical theses which taken together reveal that sincere utterances of indicative moral sentences commit us to ‘objectively prescriptive values’. I then go on to defend the arguments of J.L. Mackie and Richard Joyce that such values do not exist, and thus indicative moral sentences are systematically untrue. In the second chapter I deal with five objections to error theory: (i) error theory is self-undermining; (ii) error theory defies commonsense; (iii) error theory is defeated by a modal counterargument; (iv) moral error theory entails an absurd epistemic error theory; (v) the error theorist’s denial that there are any categorical imperatives is untenable, as it is constitutive of being a rational agent that one is guided by certain categorical norms. I show how each of these objections can be dealt with.In the third chapter I begin to look at what we should do with moral discourse once we have accepted error theory. The main foci of this chapter are eliminativism (the thesis that we ought to stop engaging in moral discourse) and reformist realism (the thesis that we should modify the semantics of moral discourse so that our moral terms can successfully refer). I argue that the rationales that have been provided for eliminativism, such as that moral societies are harmful to most of their members, and that it always harmful to make untrue judgements, are unpersuasive. I consider the most plausible way of being a reformist realist is to argue that we should become moral relativists, but I argue that such a move would be unstable and we would revert to non-relativist type. In the fourth chapter I focus on moral fictionalism (the thesis that we should continue to use indicative moral sentences, while adopting some attitude to them other than belief). One of the more interesting motivations that has been offered for moral fictionalism is that moral discourse either facilitates or is essential for some non-moral description. I find no evidence for the stronger claim, but argue that there is some plausibility in the weaker claim. Another interesting suggestion (made by Joyce) is that pretending that certain actions are morally required or forbidden will help motivate prudent behaviour. I argue that although it is very plausible that thinking in moral terms can motivate prudent behaviour, Joyce fails to provide a convincing argument that we can retain these positive motivational effects if we abandon moral belief. In light of this, I argue that the only way for error theorists to retain the positive motivational aspect of moral discourse is by becoming conservationists. The conservationist argues that we can and should continue to form and be guided by genuine moral beliefs, even if we have become convinced of the error theory. Naturally, conservationism is open to a variety of objections, and I deal with the ones that seem most pressing.