Metaethics, a branch of philosophy, fundamentally questions the nature of morality itself, rather than prescribing specific moral rules or principles as normative ethics does. It probes into the meaning of moral terms like "good" and "bad," the status of moral judgments—are they objective truths or subjective expressions?—and the very possibility of moral knowledge. While normative ethics asks "What actions are right or wrong?", metaethics asks "What does it mean for an action to be right or wrong?" and "Can we truly know what is right or wrong?". This inquiry is crucial for understanding the foundations of our ethical beliefs and the coherence of ethical discourse. Two primary camps emerge in metaethical debates: moral realism, which posits that objective, mind-independent moral truths exist, and anti-realism, which denies this. Within these broad categories, various theories attempt to explain the ontological and epistemological status of morality.
Moral realism, in its various forms, asserts that moral properties are real and objective features of the world. For instance, a strong form, often called moral naturalism, suggests that moral properties are identical to, or reducible to, natural properties. G.E. Moore, while critical of certain naturalistic fallacies, himself engaged with the idea of intrinsic goodness as a non-natural property discoverable through intuition. Later thinkers, like Richard Hare with his prescriptivism, offered a more sophisticated, though still broadly realist, account where moral judgments function as universalizable commands. A key challenge for moral realism is explaining how we can know these objective moral truths. Epistemological theories associated with realism often point to intuition, reason, or even a form of moral perception. The existence of widespread moral disagreement across cultures and history, however, poses a significant hurdle for the claim of objective, universally binding moral truths. If morality were objective, why is there such persistent divergence in ethical beliefs?
Anti-realist positions reject the notion of objective, mind-independent moral truths. Emotivism, popularized by A.J. Ayer, argued that moral statements are not assertions of fact but rather expressions of the speaker's emotions or attitudes. Saying "Stealing is wrong" is akin to saying "Boo, stealing!" This view, however, struggles to account for the apparent rationality and argumentative nature of moral discourse. If moral statements are mere exclamations, how can we meaningfully debate ethical issues or persuade others through reasoned argument? Prescriptivism, developed by R.M. Hare, offers a more robust anti-realist alternative by focusing on the prescriptive, or action-guiding, nature of moral language. For Hare, moral statements are universalizable imperatives. While not claiming objective facts in the way naturalists do, prescriptivism allows for reasoned argument and evaluation within moral discourse by appealing to universal principles. Another prominent anti-realist stance is error theory, championed by J.L. Mackie, which claims that all positive moral claims are false because there are no objective moral properties in the world to make them true. Mackie famously argued for the "queerness" of objective moral values, suggesting they would have to be entities with a peculiar, unobservable nature, which he found implausible.
The debate between realism and anti-realism has profound implications for how we understand moral responsibility, moral progress, and the very possibility of ethics as a rational discipline. If morality is purely subjective or emotional, then moral claims may lack the normative force we intuitively attribute to them. Conversely, if morality is objective, we face the challenge of explaining its nature and our access to it. The ongoing discussions in metaethics, from sophisticated forms of constructivism that see moral truths as arising from rational agreement, to nuanced forms of realism that accommodate moral phenomenology, highlight the enduring philosophical puzzle of what morality truly is and how it functions in our lives. Ultimately, metaethics forces us to confront the deep assumptions underlying our ethical lives and to question the very ground upon which our moral judgments stand.