The challenge to objective values › What the argument leaves open

Rejecting objective prescriptivity does not logically remove human needs, attachments, or vulnerability. It also does not determine a complete moral code. A person who accepts Mackie's second-order conclusion still faces choices about how to live with others.

Consider an original example of two people deciding how to share care for a relative. They may agree that the work must be done and disagree about how to distribute it. Describing their interests and dependencies can inform deliberation even if neither appeals to a value existing independently of all human concerns.

The example does not prove that negotiation yields justice or that a skeptic can reproduce every feature of objective obligation. It shows why the practical problem survives the metaphysical dispute. People still need to make decisions under conditions of conflicting interests and limited resources.

Conversely, a recommendation to preserve useful moral practices does not follow from error theory alone. It requires further commitments about what matters and what arrangements deserve support. A title about inventing morality should not be read as a deduction that any invention is equally acceptable.

The need for those further commitments is one reason Mackie's theory can be demanding. It removes one claimed foundation without automatically providing an agreed replacement. Whether that loss is fatal to ethical reasoning is a substantive objection to examine, rather than an implication to assume.