Metaethics is a fundamental branch of philosophy that explores the nature, scope, and meaning of moral judgments, beliefs, and values, setting it apart from normative ethics (how one ought to act) and applied ethics (practical moral dilemmas). It addresses "second-order" questions like "What is goodness?" or "How can we know right from wrong?" rather than evaluating specific actions. Philosophers Richard Garner and Bernard Rosen identify three core problems in metaethics: understanding the meaning of moral terms (moral semantics), the intrinsic nature of moral judgments (moral ontology), and how these judgments can be supported or justified (moral epistemology). Key theoretical approaches include cognitivism, which posits that moral statements express propositions capable of being true or false (e.g., moral realism), and non-cognitivism, which views them as expressions of emotions or commands. Although metaethics doesn't prescribe specific moral actions, its findings have profound implications for the validity and interpretation of all ethical claims.