Metaethics investigates the foundations, nature, and methodology of ethics itself rather than prescribing how to act. It asks whether moral claims can be true or false, what moral language means, whether moral facts exist independently of minds, and how moral knowledge is possible. Metaethics sits beneath normative ethics—you can adopt a first-order view like utilitarianism while still disagreeing at the metaethical level about what makes it correct. The main metaethical positions divide over cognitivism (moral claims are truth-apt propositions) versus non-cognitivism (they express something else), and over moral realism (moral facts are mind-independent) versus anti-realism.
Begin by reading the opening chapters of a metaethics anthology (e.g., Shafer-Landau's Foundations of Ethics). Practice by asking of any normative claim: is this stating a fact, expressing an attitude, or prescribing action? Compare metaethics to philosophy of language and philosophy of science to see structural parallels.
When you study normative ethics — consequentialism, deontology, virtue ethics — you are asking: what should I do, and why? Those questions take it for granted that moral claims can be evaluated for correctness. Metaethics does not take this for granted. It steps back and asks: what *kind* of thing is a moral claim? Can it be true or false? If so, what would make it true? And how could we ever know?
The first major divide is between cognitivism and non-cognitivism. Cognitivists hold that moral statements express beliefs — propositions that are either true or false. When you say "torture is wrong," you are stating something that can be assessed for accuracy, just like "the earth is round." Non-cognitivists disagree: they hold that moral sentences do not express truth-apt beliefs at all. An expressivist (one variety of non-cognitivist) says "torture is wrong" expresses disapproval of torture — more like "Boo, torture!" than a factual claim. This distinction matters enormously: if moral claims aren't truth-apt, then moral disagreements might not really be disagreements about facts, and the usual tools of argument may not apply in the way we assume.
Among cognitivists, the next divide is between moral realism and anti-realism. Moral realists hold that some moral statements are true, and that what makes them true is mind-independent — moral facts exist in the world the way chemical facts do, regardless of what anyone believes. Anti-realists deny this. Error theory (associated with J.L. Mackie) is a cognitivist but anti-realist position: moral statements are truth-apt and express genuine beliefs, but all such beliefs are false because there are simply no moral facts in the world. Relativism takes a different anti-realist route: moral truths exist but are relative to cultures or frameworks, not mind-independent. Understanding which combinations of these positions are coherent is a central task of metaethics.
Your prerequisites are directly engaged here. Argument structure lets you evaluate whether metaethical positions are internally consistent — error theory, for instance, faces the challenge of explaining why we should believe its own conclusion if all normative claims are false. Propositional semantics informs the cognitivism/non-cognitivism debate: if moral sentences have the logical form of propositions (subject-predicate, capable of negation, embedding in conditionals), there is pressure toward cognitivism; if they function more like commands or exclamations, non-cognitivism gains plausibility. Metaethics is where philosophy of language and ethics intersect most directly.
Topics in reflective domains aren't scored by quiz answers. Read, reflect, and mark when you've thought it through.