Relying on yesterday's prelude, let's dive right in. If I understand it correctly, the error theory holds that (1) cognitivism is right about what ethical statements try to do but, (2) cognitivism is wrong in that ethical statements ALWAYS fail to do it, to convey knowledge. Error theorists rather boldly refuse to re-interpret such errors in non-cognitivist fashion to turn them into anything that could be non-erroneous. An ethical statement in the pertinent sense says that some normative predicate is true of some subject. The classic text for error theory is J.L. Mackie, ETHICS: INVENTING RIGHT AND WRONG (1977). It contends that there are no true statements with normative predicates -- that is, of the form "X is just" or "X is a breach of trust." In arguing for this view, Mackie coined the phrase, "the argument from queerness." He contended that ethical statements could possibly be right only if ethical facts somehow "supervene...