The Right Argument from Moral Disagreement

The anti-realist's argument from moral disagreement has prematurely fallen out of favor. The argument has never been stated explicitly in correct form, and its proponents have not appealed to the best examples to support its premises. Realists have responded with a multitude of possible replies without applying them to the most convincing examples of irresolvable disagreements. The argument is a modus ponens from apparent fundamental disagreements to a disjunction of possible explanations, and then a disjunctive argument eliminating all but one alternative. The most convincing example from the point of view of the anti-realist is the disagreement between the collectivist and the individual rights advocate, which occurs on both the levels of principle and individual judgment. Realist explanations for such disagreements include ignorance of nonmoral facts, application of principles in diverse contexts, bias, faulty reasoning, incommensurability or ties, lack of empathy or imagination, inaccessibility of moral facts, or different meanings for moral terms. I argue that none of these realist explanations for the disagreement between the collectivist and the individualist works, leaving only the anti-realist explanation. Other realist moves, for example analogies with other areas of discourse, including disagreement among meta-ethicists, are also shown to fail.