Moral Skepticism - Moral Error Theory

Moral Error Theory

Moral error theory is a position characterized by its commitment to two propositions: (i) all moral claims are false and (ii) we have reason to believe that all moral claims are false. The most famous moral error theorist is J. L. Mackie, who defended the metaethical view in Ethics: Inventing Right and Wrong (1977). Mackie has been interpreted as giving two arguments for moral error theory.

The first argument people attribute to Mackie, often called the Argument from Queerness, holds that moral claims imply motivation internalism (the doctrine that "It is necessary and a priori that any agent who judges that one of his available actions is morally obligatory will have some (defeasible) motivation to perform that action" ). Because motivation internalism is false, however, so too are all moral claims.

The other argument often attributed to Mackie, often called the Argument from Disagreement, maintains that any moral claim (e.g. "Killing babies is wrong") entails a correspondent "reasons claim" ("one has reason not to kill babies"). Put another way, if "killing babies is wrong" is true then everybody has a reason to not kill babies. This includes the psychopath who takes great pleasure from killing babies, and is utterly miserable when he does not have their blood on his hands. But, surely, (if we assume that he will suffer no reprisals) this psychopath has every reason to kill babies, and no reason not to do so. All moral claims are thus false.