The challenge to objective values › Why the position is an error theory

Mackie does not simply reinterpret ordinary moral judgments as reports of preferences. His account says that moral thought makes a claim it fails to satisfy. That is why he describes it as an error theory (chapter 1, sections 5–7).

There is a conceptual claim about what ordinary moral judgments purport to assert, followed by an ontological claim about what exists. If the purportedly objective values are absent, judgments that positively ascribe those values cannot be true as intended. The error is systematic because it concerns the kind of authority claimed, rather than an isolated mistake about a particular action.

Care is needed with the slogan that every moral sentence is false. A theory about positive moral ascriptions is not permission to ignore negation, conditional sentences, or statements about what a community believes. "This community prohibits betrayal" may be a true descriptive report even if the community's claim to objective authority is mistaken.

The same caution applies to the thought that error theory establishes the opposite of every moral judgment. Denying that an action has an objective property of wrongness does not establish that it has an objective property of rightness. Mackie's challenge concerns the supposed objective status of value, not a reversal of the conventional moral ranking.

There are two main ways to resist the theory. One can dispute his account of what moral thought claims, or one can defend the existence of objective values. A successful criticism of only one part would already undermine the argument connecting ordinary moral thought to systematic error.