  Error theorists and skeptics about moral truth-aptness disagree about the content of moral assertions, but they still agree that no substantive moral claim or belief is true, so they are both skeptics about moral truth. None of these skeptical theses is implied by either skepticism about moral knowledge or skepticism about justified moral belief. Some moral claims might be true, even if we cannot know or have justified beliefs about which ones are true. However, a converse implication seems to hold: If knowledge implies truth, and if moral claims are never true, then there is no knowledge of what is moral or immoral (assuming that skeptics deny the same kind of truth that knowledge requires). Nonetheless, since the implication holds in only one direction, skepticism about moral truth is still distinct from all kinds of epistemological moral skepticism.