Moral Realism

1. Introduction

Moral realism is a position in metaethics, the branch of philosophy that examines the status, meaning, and justification of moral claims. Unlike normative ethical theories (such as utilitarianism or deontology), which ask what we ought to do, moral realism addresses the more fundamental question of whether there are objective moral facts or truths at all, and what kind of things they would be.

Realist views maintain that at least some moral statements—such as “cruelty is wrong” or “keeping promises is good”—are not merely expressions of emotion, social convention, or personal preference. Instead, they purport to describe how things stand in a moral reality that is, in some sense, independent of what any individual or group thinks or feels. Anti-realist views deny this, either by holding that moral discourse systematically misdescribes reality, or by reinterpreting moral language in non-factual terms.

Within moral realism, philosophers disagree about the nature of moral facts (for example, whether they are natural properties or irreducibly normative), about their relationship to scientific facts, and about how we might know them. These internal debates have produced a family of realist positions, including non-naturalist realism, naturalist realism, and constructivist forms of realism, as well as distinctions between robust and more minimal or quasi-realist understandings of objectivity.

Moral realism has played a central role in the history of ethics, from ancient accounts that linked morality to virtue and human flourishing, through medieval theological theories that grounded moral truth in God or natural law, to contemporary analytic debates about reference, truth conditions, and moral explanation. It also intersects with questions in the philosophy of science, religion, politics, and law, where the possibility of objective moral standards bears on issues such as human rights, justice, and moral progress.

This entry surveys how moral realism is defined, the main varieties of the view, major arguments for and against it, and its connections to other areas of inquiry, while also situating it within its historical and contemporary philosophical context.

2. Definition and Scope of Moral Realism

2.1 Core Definitional Commitments

Most accounts characterize moral realism in terms of three related theses:

1. Cognitivism about moral discourse: Ordinary moral sentences (e.g., “lying is wrong”) express beliefs and aim to state truths or falsehoods, rather than merely venting emotions or issuing commands.

2. Truth-apt moral content: At least some moral propositions are true.

3. Stance-independence: The truth of (at least some) moral propositions does not constitutively depend on any agent’s or group’s actual attitudes, endorsements, or conventions. Realists often say there are moral facts that make true moral statements true.

These points distinguish moral realism from views that deny any of them, such as noncognitivism (which rejects 1), error theory (which rejects 2), and subjectivist or relativist theories (which typically reject 3, in whole or part).

2.2 What Counts as “Objective”?

Realists typically describe moral facts as objective. Here, “objective” does not necessarily mean “mind-independent in every respect,” but minimally:

• Moral truths are not simply fixed by individual preferences or by whatever norms a society happens to accept.
• There can be genuine moral disagreement where at most one side is correct.
• Moral judgments can be mistaken even when widely shared.

Some realists add stronger conditions—such as full mind-independence from all possible attitudes—while others adopt weaker notions compatible with some dependence on rational procedures or idealized agreements.

2.3 Scope: What Is Moral Realism About?

The “moral” domain is interpreted in various ways:

• Deontic claims (right, wrong, obligatory, permissible)
• Axiological claims (good, bad, better, worse)
• Virtue and character (just, courageous, cruel)
• Reasons and oughts (what there is reason to do, what agents ought to do)

Some theorists treat all of these as falling under moral realism; others restrict realism to, for example, reasons or oughts, while being more deflationary about virtue talk or value judgments.

Moral realism is also distinguished from:

The scope of moral realism is thus defined by the kinds of normative claims it treats as truth-apt and objectively assessable, leaving open substantive questions about which moral claims are actually true and how they are grounded.

3. The Core Question of Moral Objectivity

Moral realism is structured around a central problem: in what sense, if any, are moral judgments objectively correct or incorrect? This “core question of moral objectivity” can be unpacked into several dimensions.

3.1 Stance-Independence and Correctness

The primary issue is whether moral claims admit of stance-independent correctness. Realists maintain that:

• Some moral judgments are true independently of what any person or group believes, desires, or endorses.
• Moral disagreements are, at least in part, about facts rather than merely clashing preferences.

Anti-realists deny this, holding that moral “correctness” is ultimately reducible to, or constituted by, some set of attitudes, conventions, or practical stances.

3.2 The Nature of Moral Facts

The question of objectivity also concerns what kind of facts would make moral claims true:

• Are they natural facts (e.g., about well-being, social practices, evolutionary fitness)?
• Are they non-natural normative facts, irreducible to scientific description?
• Are they constructed by ideal rational procedures, yet still objective for any agent who satisfies those procedures?

Different realist camps answer this question differently, while sharing the core commitment that there is something independent of mere opinion that moral judgments answer to.

3.3 Normativity and Reasons

Another aspect of objectivity concerns normativity: the idea that moral truths provide reasons for action. The core question here is whether:

• Moral facts are themselves reason-giving, such that if an act is wrong, one thereby has a reason not to do it; or
• Normativity is instead grounded in agents’ desires, aims, or commitments, in which case moral “objectivity” might be more limited.

Debates over motivational internalism and externalism explore whether the link between moral judgment and motivation is conceptual or contingent, and what this implies for objectivity.

3.4 Disagreement, Convergence, and Progress

Finally, the question of moral objectivity is pressed by observed moral disagreement and claims about moral progress. Key issues include:

• Whether persistent disagreement undermines the idea of objective moral facts.
• Whether apparent historical convergence (e.g., on slavery or human rights) suggests approximation to stance-independent standards.
• How to interpret talk of moral error, learning, and improvement if morality is not objectively constrained.

The rest of the entry examines how historical and contemporary theories answer these interconnected facets of moral objectivity.

4. Historical Origins and Ancient Approaches

Ancient philosophical traditions did not typically frame debates in explicitly “metaethical” terms, but many offered views that contemporary scholars interpret as early forms of moral realism or proto-realism.

4.1 Plato and Objective Moral Forms

Plato is often read as an early moral realist. In dialogues such as the Republic and Gorgias, he connects morality with an objective order of Forms or Ideas, especially the Form of the Good.

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“The Good is the cause of all that is right and beautiful.”

— Plato, Republic VI

On one interpretation, the goodness or justice of actions is grounded in timeless, non-empirical realities accessible through rational insight. Moral truths are not relative to opinion; “conventional” morality may be mistaken when it departs from this objective standard.

4.2 Aristotle, Virtue, and Human Nature

Aristotle’s ethics links moral truth to facts about human nature and flourishing (eudaimonia). In the Nicomachean Ethics, he treats virtues such as courage and justice as excellences that enable humans to function well in accordance with their rational nature.

On this view:

• Moral evaluation is answerable to objective facts about what humans are like.
• There can be better and worse accounts of happiness, grounded in an understanding of human capacities and social life.

Some interpret Aristotle as a form of naturalist realist, since moral properties supervene on, or are constituted by, natural facts about human beings and their characteristic forms of life.

4.3 Stoics, Epicureans, and Hellenistic Developments

The Stoics held that living “according to nature” and in agreement with universal reason (logos) yields an objectively correct way of life. Virtue is the sole true good, and moral norms reflect a rational cosmic order.

The Epicureans, by contrast, grounded the good in pleasure and the absence of pain, understood naturalistically. While they treated pleasure as the ultimate standard, they still regarded claims about what conduces to tranquility as objectively correct or incorrect based on human psychology and the structure of the world.

4.4 Ancient Skepticism and Relativist Tendencies

Sophistic writers and later skeptics raised challenges that anticipate modern anti-realist arguments. They emphasized:

• The diversity of moral codes across cultures.
• The difficulty of justifying one ethical outlook over others.

Such observations suggested that morality might be rooted in nomos (custom) rather than physis (nature). However, most major ancient systems—Platonism, Aristotelianism, and Stoicism—retained some commitment to objective standards of virtue, flourishing, or rational order.

5. Medieval Theological Realism and Natural Law

In medieval philosophy, discussions of moral objectivity were deeply intertwined with theology. Many thinkers developed robust forms of moral realism by grounding moral truths in God, eternal law, or human nature.

5.1 Divine Nature and Eternal Law

For Christian, Jewish, and Islamic philosophers, moral order was commonly seen as reflecting God’s nature and will. On one influential strand, articulated by Thomas Aquinas:

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“The natural law is nothing else than the rational creature’s participation in the eternal law.”

— Thomas Aquinas, Summa Theologiae I–II, q. 91

Here:

• Eternal law is the divine ordering of creation.
• Natural law is the way in which rational creatures grasp this order through reason.
• Moral truths are objective because they are rooted in the structure of creation and the nature of God, not in human opinion.

5.2 Natural Law as Moral Realism

Medieval natural law theory holds that certain basic moral principles (e.g., preserving life, promoting procreation, seeking truth, living in society) are:

• Knowable by reason, even without revelation.
• Universally binding, given shared human nature.
• Objective, since they flow from facts about what humans are and what fulfills them.

This provides a realist framework in which moral properties are grounded in teleological features of human beings: what is good is what perfects or fulfills the nature given by God.

5.3 Voluntarism and Divine Command Tendencies

Some medieval thinkers, especially in the voluntarist tradition (e.g., Duns Scotus, later William of Ockham), emphasized God’s will more strongly. On many divine command accounts, moral obligations are constituted by God’s commands.

This raises the classical Euthyphro problem: Are actions right because God commands them, or does God command them because they are right? Medieval debates explored whether:

• Moral truths are independent standards that even God recognizes (risking a limit on divine omnipotence), or
• Moral truths are created by divine will, in which case their objectivity depends on the attributes of God (e.g., perfect goodness, wisdom).

Both approaches aim to secure objectivity, though in different ways: through either the necessity of divine nature and eternal law, or the authoritative will of a perfectly good deity.

5.4 Cross-Tradition Parallels

Similar patterns appear in Islamic and Jewish philosophy (e.g., Al-Ghazali, Maimonides), where moral norms are:

• Grounded in God’s wisdom and justice.
• At least partly accessible to human reason.
• Treated as universal in scope, even though historically mediated through specific religious laws.

Medieval theological realism thus combines metaphysical commitment to a divinely ordered moral structure with attempts to explain how finite, rational agents can know and respond to that structure.

6. Modern Transformations: Rationalism, Sentimentalism, and Skepticism

The early modern period introduced new frameworks that reshaped moral realism, often by reconsidering the roles of reason, sentiment, and skepticism.

6.1 Rationalist Moral Realism

Rationalist philosophers such as Samuel Clarke and later Immanuel Kant argued that moral truths are grounded in reason itself.

• For Clarke and other early rationalists, moral relations (e.g., fitness, proportionality) are as necessary and knowable as mathematical truths.
• Kant rooted morality in the form of rational agency. The Categorical Imperative articulates principles that any rational being must acknowledge.

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“Act only according to that maxim whereby you can at the same time will that it should become a universal law.”

— Immanuel Kant, Groundwork of the Metaphysics of Morals

On Kantian readings with realist leanings, moral requirements are objective because they are grounded in the necessary structure of rational will, rather than in contingent desires or social norms.

6.2 Sentimentalism and the Role of Emotions

In contrast, sentimentalist thinkers such as David Hume and Adam Smith emphasized moral sentiments and human psychology.

• Hume claimed that moral distinctions are “not deriv’d from reason” but from feelings of approval and disapproval.
• Smith’s Theory of Moral Sentiments explains moral judgments through sympathy and imaginative perspective-taking.

These views often interpret moral judgments as tracking stable, generalizable human responses. Some contemporary interpreters see in them the seeds of:

• Anti-realist or subjectivist theories (if morality is ultimately about feelings).
• Or naturalist realist approaches (if these shared sentiments reveal objective features of human flourishing and social life).

The extent to which Humean sentimentalism is compatible with full-blown moral realism remains a matter of scholarly debate.

6.3 Skepticism and the Is–Ought Gap

The modern era also crystallized systematic skepticism about objective moral truth. Hume’s famous remark that one cannot derive an “ought” from an “is” suggested a deep gap between descriptive and normative statements.

Coupled with increasing awareness of:

• Cultural variation in moral norms, and
• The successes of the natural sciences,

this skepticism prompted questions about whether moral properties could fit into an emerging scientific world-picture. Later critics, including Nietzsche, intensified doubts by offering genealogies of morality that treated values as products of power, resentment, or social control.

6.4 Utilitarianism and Empirical Tendencies

Modern utilitarian theories (e.g., Bentham, Mill, Sidgwick) introduced more explicitly consequentialist frameworks. While some utilitarians were realists about the goodness of pleasure or happiness, their emphasis on empirical consequences and human welfare also opened the door to naturalistic reinterpretations of moral value, anticipating later moral naturalism.

Overall, modern thought diversified the landscape: rationalist, sentimentalist, and skeptical strands all influenced subsequent realist and anti-realist positions in analytic ethics.

7. Non-naturalist Moral Realism in Analytic Ethics

Non-naturalist moral realism emerged as a prominent position in 20th‑century analytic philosophy, especially following G. E. Moore. It maintains that there are irreducibly normative moral facts or properties that are not identical to any natural or scientific facts.

7.1 Moore and the Open-Question Argument

In Principia Ethica (1903), G. E. Moore argued against identifying moral properties with natural properties (e.g., pleasure, desire-satisfaction). His open-question argument runs, roughly, as follows:

• For any proposed naturalistic definition of “good” (e.g., “good” = “pleasurable”), it remains an intelligible open question whether that property is indeed good.
• This suggests that “good” does not mean any natural property term; therefore, goodness is non-natural.

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“Good is good, and that is the end of the matter.”

— G. E. Moore, Principia Ethica

Moore also accused naturalistic theories of committing the naturalistic fallacy: illicitly inferring normative conclusions from merely descriptive premises.

7.2 The Non-naturalist Package

Contemporary non-naturalist realists, such as Derek Parfit, Thomas Nagel, David Enoch, and Russ Shafer-Landau, typically endorse a cluster of theses:

• Irreducibility: Moral properties (e.g., wrongness, fairness) are not identical to, or reducible to, natural properties.
• Robust normativity: Moral facts are intrinsically reason-giving and cannot be captured in purely descriptive terms.
• Autonomy of the moral: Moral truths are sui generis, even though they supervene on natural facts (no moral difference without some natural difference).

These philosophers often defend a robust form of realism, willing to accept a more expansive ontology to preserve the distinctive character of moral normativity.

7.3 Queerness and Responses

Non-naturalism faced influential criticism from J. L. Mackie, who argued that objective moral values would be “queer”:

• Metaphysically queer: unlike anything else in the universe, with built-in prescriptivity.
• Epistemologically queer: requiring mysterious faculties of moral intuition to know them.

Non-naturalist realists respond in various ways:

• Some embrace a form of rational intuitionism, likening moral knowledge to mathematical or logical insight.
• Others, influenced by John McDowell, argue that sensitivity to moral reasons can be understood as a cultivated second nature, not as a supernatural faculty.
• Still others emphasize that ontological “queerness” is overstated and that many domains (e.g., modality, mathematics) involve entities not easily reduced to natural science.

7.4 Contemporary Developments

Recent non-naturalist realism often employs sophisticated tools from:

• Metaphysics (e.g., grounding, dependence, supervenience),
• Philosophy of language (e.g., reference and semantic externalism), and
• Normative theory (e.g., reasons-first approaches).

Debates focus on whether non-naturalist realism can offer a plausible epistemology, avoid explanatory redundancy, and reconcile its commitments with a scientifically informed worldview, while preserving a strong sense of moral objectivity.

8. Naturalist Moral Realism and Moral Naturalism

Naturalist moral realism, or moral naturalism, seeks to vindicate the objectivity of morality while remaining within a broadly naturalistic picture of the world. It identifies or reduces moral properties to natural or social properties studied by the empirical sciences.

8.1 Defining Moral Naturalism

Moral naturalists endorse:

• Ontological continuity: All that exists is, in principle, part of the natural world; moral facts are not a separate, non-natural realm.
• Supervenience: Moral facts depend on, and are fixed by, non-moral natural facts—no moral difference without a natural difference.
• Identity or reduction: Moral properties are identical to, or realized by, sufficiently complex natural or social properties (e.g., patterns of well-being, institutional arrangements, psychological states).

Naturalism aims to respect both scientific constraints and the realist intuition that moral claims can be objectively true.

8.2 Cornell Realism and Response-Dependent Views

One influential strand is Cornell realism, associated with philosophers like Richard Boyd, Peter Railton, and Nicholas Sturgeon. They argue that:

• Moral properties are higher-level natural properties that play roles in causal explanations (e.g., explaining behavior or social outcomes).
• Moral terms refer to these properties via theoretical roles, analogous to scientific terms (e.g., “gene,” “electron”).

Railton, for instance, reduces moral “goodness” to what would be rationally approved under conditions of full information and idealized deliberation, construed entirely within naturalistic psychology and social theory.

Other naturalists propose response-dependent accounts, where moral properties are identified with properties that would elicit certain responses in ideally situated observers (e.g., fully informed, impartial, empathetic). These responses are themselves natural psychological states.

8.3 Challenges from the Open-Question Argument

Moral naturalism faces the legacy of Moore’s open-question argument, which seems to show that “good” cannot mean any natural property. Naturalists typically reply by distinguishing:

• Semantic reduction (about meanings), which they may reject, from
• Metaphysical reduction or identity (about what properties are), which they defend.

On this view, it can remain conceptually open whether, say, “maximizes well-being” is good, even if, as a matter of fact, the property of goodness just is the property of maximizing well-being—much as “water” and “H₂O” are co-referential despite different meanings.

8.4 Explanatory Role and Normative Force

Naturalist realists argue that moral properties can:

• Figure in causal explanations (e.g., a just policy leads to social stability).
• Be indispensable to our best social-scientific theories.

Critics question whether naturalism can capture the normative force of morality: the sense in which moral facts are intrinsically reason-giving rather than merely descriptive. Naturalists respond by developing accounts of how facts about well-being, cooperation, or practical rationality can underpin genuine reasons for action without invoking non-natural entities.

Moral naturalism thus represents a major strategy for reconciling moral realism with scientific naturalism, while facing ongoing debates about reduction, normativity, and the is–ought gap.

9. Constructivist and Procedural Conceptions of Moral Truth

Constructivist approaches reinterpret moral objectivity in terms of idealized procedures of reasoning, choice, or agreement, rather than positing independent moral facts in the way non-naturalists or many naturalists do.

9.1 Kantian Roots of Constructivism

Metaethical constructivism is often traced to Kant, for whom moral requirements arise from the form of rational agency. On one influential reading:

• Moral principles are the outcome of procedures of universalization (the Categorical Imperative).
• These procedures express the constitutive standards of being a rational, autonomous agent.

Contemporary Kantians such as Christine Korsgaard argue that moral truths are not “discovered” in a mind-independent moral realm, but are “constructed” by rational agents through the endorsement of principles that can be willed as universal laws.

9.2 Procedural Objectivity

Constructivists maintain that moral truths can be objective even if they are procedurally dependent:

• Objectivity arises from the constraints of rationality, impartiality, or fair cooperation.
• A principle is morally correct if it would be agreed to in an idealized procedure, such as:
  • A Rawlsian original position behind a veil of ignorance.
  • An ideal discourse situation in Habermasian discourse ethics.
  • A fully reflective equilibrium of an agent’s considered judgments.

These procedures aim to filter out arbitrariness, bias, and contingent preferences, yielding standards that any similarly situated rational agent would accept.

9.3 Constructivism and Realism

There is debate about whether constructivism counts as a form of moral realism:

• Some proponents describe their views as “constructivist realism”, emphasizing that once constructed by the correct procedure, moral truths are binding on all agents who meet its conditions.
• Critics argue that because moral truths are essentially dependent on our rational practices, constructivism is better understood as a sophisticated anti-realist or subjectivist position.

The classification often turns on how strictly one understands stance-independence: if dependence on idealized rational agency is permissible, constructivism may qualify as realist in a broad sense; if not, it may fall outside realism.

9.4 Challenges and Variants

Issues for constructivist accounts include:

• Relativization worry: Different reasonable procedures or starting points may yield different moral systems.
• Circularity: Justifying the choice of a particular procedure (e.g., Rawls’s original position) may itself seem to require substantive moral assumptions.
• Hard cases: In deeply contested moral questions, procedural approaches may underdetermine specific outcomes.

Nevertheless, constructivist and procedural conceptions exert significant influence by offering a way to reconcile normative authority and practical relevance with a reluctance to posit robust, independent moral entities.

10. Arguments For Moral Realism

Philosophers have developed a variety of arguments in support of moral realism. These arguments differ in focus—some appeal to features of moral experience, others to language, practice, or explanation.

10.1 Moral Phenomenology and Experience

Many realists point to the phenomenology of moral experience:

• When people judge that an act is cruel or unjust, it often seems to them that they are tracking features of the world, not merely reporting feelings.
• Moral requirements are experienced as authoritative and sometimes constraining, even against our desires.

Realists suggest that the best explanation of this experience is that there are objective moral facts to which our judgments are responsive.

10.2 Argument from Discourse and Practice

Another line of argument focuses on ordinary moral discourse:

• We treat moral disagreements as if one side is mistaken, not merely differently disposed.
• We use moral language with truth conditions, speak of error, correction, and moral progress.

Realists argue that the most straightforward interpretation of these practices is that moral claims aim at truth about an objective domain. While quasi-realists and expressivists offer alternative explanations, realists contend that these are more complex or less faithful to our self-understanding.

10.3 Explanatory and Theoretical Role

Some realists contend that moral facts play indispensable explanatory roles:

• Appeals to justice, fairness, or cruelty help explain patterns of behavior, social stability, or conflict.
• Our best explanations in history, sociology, or psychology sometimes appear to require moral predicates.

If moral properties feature in indispensable explanations, realists argue, we have reason to accept them into our ontology, much as we do with theoretical entities in science.

10.4 Argument from Convergence and Progress

Realists sometimes cite apparent moral convergence and progress:

• Historical shifts, such as the abolition of slavery or expanded recognition of human rights, are widely regarded as improvements, not mere changes in taste.
• There appears to be at least partial convergence on certain norms (e.g., prohibitions on gratuitous cruelty).

Realists claim that such patterns are best understood as societies moving closer to stance-independent moral truths, rather than simply reshuffling preferences.

10.5 Arguments from Rationality and Reasons

Finally, some arguments ground realism in practical reason:

• If agents have objective reasons to act in certain ways regardless of their contingent desires, these reasons may be understood as grounded in moral facts.
• Rationalist realists suggest that the structure of rational deliberation itself points to the existence of truths about what one ought to do that are not reducible to mere preferences.

These various arguments are often combined, and different realist camps emphasize different strands, but together they aim to show that moral realism best explains central features of our moral lives and thought.

11. Arguments Against Moral Realism and Anti-Realist Alternatives

Opponents of moral realism advance a range of arguments challenging the existence, knowability, or necessity of objective moral facts. These arguments often motivate alternative metaethical positions.

11.1 The Argument from Queerness

J. L. Mackie’s argument from queerness is one of the most influential critiques:

• Metaphysical queerness: Objective moral values would be unlike any other properties—intrinsically prescriptive and reason-giving.
• Epistemological queerness: Knowing such properties would require a special faculty of moral perception or intuition.

Mackie concludes that it is more plausible to regard moral discourse as systematically in error—hence his error theory, according to which all positive moral claims are false.

11.2 Disagreement and Relativism

Another line of criticism emphasizes persistent, deep moral disagreement:

• Across cultures and historical periods, people hold radically different moral views.
• Disagreement remains even under conditions of apparent rational reflection and information.

Some argue that the best explanation is that there are no objective moral facts to converge upon. This can lead to forms of relativism (truth relative to cultures or frameworks) or subjectivism (truth relative to individual attitudes).

11.3 Motivational Internalism and Noncognitivism

Many anti-realists appeal to motivational internalism, the view that sincere moral judgments are necessarily linked to motivation:

• If judging “X is wrong” necessarily involves some motivation not to do X, then moral judgments seem unlike ordinary factual judgments, which can be made coolly and without motivation.
• This motivates noncognitivist theories (e.g., emotivism, expressivism), which analyze moral sentences as expressions of attitudes, prescriptions, or commitments rather than beliefs.

On such views, moral language does not aim to describe objective moral facts, undermining a central realist commitment.

11.4 Evolutionary Debunking Arguments

Some critics use evolutionary explanations of moral judgment to challenge realism:

• Our moral dispositions may have been shaped primarily by natural selection for cooperation, group cohesion, and survival, not for tracking objective moral truths.
• If so, then the reliability of our moral beliefs, conceived as beliefs about stance-independent facts, is undermined.

This supports debunking arguments: if the causal origin of our moral beliefs is insensitive to moral truth, we have reason to doubt those beliefs, at least on a realist construal.

11.5 Parsimony and Explanatory Redundancy

From a naturalistic perspective, some contend that positing objective moral facts is ontologically extravagant:

• Social, psychological, and evolutionary facts suffice to explain moral behavior and discourse.
• Moral facts appear explanatorily redundant, adding no predictive or explanatory power.

This motivates deflationary or quasi-realist approaches that aim to capture the practical functions of moral talk (disagreement, criticism, commitment) without committing to robust moral reality.

These arguments against realism underpin a landscape of anti-realist views, including error theory, noncognitivism, and various forms of relativism or subjectivism, each of which offers a different reconstruction of moral language and practice.

12. Moral Epistemology: Knowing Moral Facts

Moral epistemology examines whether, and how, humans can have knowledge or justified belief about moral truths, assuming such truths exist. For moral realists, this is a central challenge: explaining our epistemic access to moral facts.

12.1 Intuitionism and Rational Insight

One traditional approach is ethical intuitionism, associated with Moore, W. D. Ross, and more recently Robert Audi:

• Certain basic moral principles or particular moral truths are self-evident or known by rational intuition.
• Intuitions are taken as prima facie evidence, defeasible but not in need of further non-moral justification.

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“It is self-evident that we should keep our promises.”

— W. D. Ross, The Right and the Good

Critics worry about the reliability and cultural variability of intuitions, as well as the apparent mystery of the faculty involved.

12.2 Coherentism and Reflective Equilibrium

Another strategy is coherentist:

• Moral beliefs are justified by fitting into a coherent web of beliefs about specific cases, general principles, and background theories.
• The method of reflective equilibrium (articulated by Rawls) involves mutual adjustment between judgments and principles until they form a stable, coherent set.

This does not require self-evident foundations, but rather a network of mutually supporting beliefs, potentially informed by empirical data and theoretical virtues (simplicity, explanatory power).

12.3 Naturalist Epistemologies

Naturalist realists often integrate moral epistemology with empirical inquiry:

• Moral knowledge is acquired through a combination of experience, scientific investigation (e.g., about well-being or social functioning), and normative reasoning.
• On some views, we learn about moral facts in ways analogous to how we learn about complex social or psychological facts.

This raises questions about whether empirical methods alone can justify normative conclusions, or whether some irreducibly normative assumptions are inevitable.

12.4 Reliability, Debunking, and Justification

Realists must also address debunking challenges:

• If our moral beliefs are shaped by factors unrelated to moral truth (culture, evolution, power relations), what secures their reliability?
• Some respond by arguing that evolutionary processes could favor alignment with moral truth (e.g., cooperation tends to be genuinely good).
• Others adopt partial debunking, allowing that some moral beliefs are unreliable while defending more robust justification for others (e.g., basic prohibitions on cruelty).

12.5 Moral Perception and Virtue Epistemology

An alternative model likens moral knowledge to perception:

• Through experience and moral education, agents develop virtues that enable them to “see” morally salient features of situations (e.g., injustice, cruelty).
• This approach, influenced by virtue epistemology and Aristotelian ethics, treats moral sensitivity as a cultivated capacity that can be evaluated for accuracy and bias.

Moral epistemology thus explores a range of models—intuitionist, coherentist, naturalist, perceptual—each offering different accounts of how moral beliefs can be justified within a realist framework, and how they respond to worries about error and cultural variability.

13. Moral Realism, Science, and Evolutionary Debunking

The relationship between moral realism and the empirical sciences, especially evolutionary biology, psychology, and neuroscience, is a central area of contemporary debate.

13.1 Scientific Studies of Moral Judgment

Cognitive science investigates:

• The development of moral cognition in children.
• The role of emotions, intuitions, and reasoning in moral decision-making.
• Neural correlates of moral evaluation.

These findings inform discussions about whether moral judgments are primarily products of automatic affective processes or deliberative reasoning, and whether such processes are conducive to tracking objective moral facts.

13.2 Evolutionary Explanations of Morality

Evolutionary psychology offers accounts of how moral dispositions might have evolved to promote:

• Kin selection and reciprocal altruism.
• In-group cohesion and cooperation.
• Punishment of free-riders.

On such views, moral judgments and norms are adaptive strategies shaped by fitness considerations, not necessarily by responsiveness to stance-independent moral truths.

13.3 Evolutionary Debunking Arguments

Some philosophers use this evolutionary story to mount debunking arguments against moral realism:

• If the causal origin of our moral beliefs lies in processes selected for survival rather than truth tracking, then those beliefs may lack epistemic justification as beliefs about objective moral facts.
• This is sometimes framed as an undercutting defeater: evolution explains why we hold certain moral beliefs without needing to posit moral truths.

Realists respond that:

• Evolution does not target truth insensitivity; survival may be better served by at least approximate alignment with moral truths (e.g., cooperation genuinely promotes flourishing).
• Even if some moral intuitions are evolutionarily shaped, reflective reasoning can revise and filter them.

13.4 Naturalist Realism and Scientific Integration

Naturalist realists often see scientific findings as supportive:

• Moral properties may be identified with complex natural properties (e.g., contributing to well-being or stable cooperation) that science can study.
• Empirical work can inform which social arrangements or actions promote flourishing, thus helping to specify the content of objectively correct moral claims, given some normative assumptions.

Debates concern whether such integration can bridge the is–ought gap without smuggling in normativity, and whether naturalist identifications can preserve the normative authority of moral facts.

13.5 Non-naturalist Realism and Scientific Autonomy

Non-naturalist realists typically maintain that:

• Moral facts are not reducible to scientific facts, but they supervene on them.
• Science can inform us about the non-moral base (facts about suffering, preferences, institutions), while normative truths about what is right or wrong remain autonomous.

They respond to evolutionary debunking by arguing that:

• Debunking arguments, if sound, might generalize to other domains (e.g., reason itself), leading to global skepticism.
• We have independent a priori or rational grounds for trusting some moral judgments, even if their origins are evolutionarily influenced.

The interaction between moral realism and science thus centers on whether empirical accounts of moral psychology and evolution undermine, support, or simply coexist with realist conceptions of objective moral truth.

14. Religious Foundations and Secular Moral Realism

Moral realism is often discussed in connection with religious and secular foundations for morality. Views differ on whether objective moral truths require a theistic basis.

14.1 Theistic Moral Realism

Many religious traditions endorse the idea that moral truths are grounded in God:

• Divine command theory: Moral obligations are constituted by God’s commands; to say “X is wrong” is (roughly) to say “God forbids X.”
• Theistic moral Platonism: Moral values are rooted in God’s nature—for example, God is essentially loving and just, and moral goodness reflects these attributes.
• Natural law: God’s rational ordering of creation endows human nature with purposes; objective moral norms derive from these purposes and are knowable by reason.

Proponents argue that theism:

• Explains the binding force of moral obligations (as commands of a supreme authority).
• Accounts for the objectivity and universality of moral norms.
• Offers a deeper metaphysical ground for moral facts than secular alternatives.

14.2 The Euthyphro Problem and Divine Grounding

Theistic realists confront the classic Euthyphro dilemma:

• If actions are right because God commands them, morality may seem arbitrary.
• If God commands them because they are right, then moral truths appear independent of God, undermining the claim that God is their ultimate ground.

Responses include:

• Locating moral goodness in God’s essential nature, which is neither arbitrary nor independent in a problematic way.
• Distinguishing between ontological dependence (moral facts exist because of God) and epistemic access (we can know them through reason or revelation).

14.3 Secular Moral Realism

Secular moral realists maintain that moral facts do not depend on the existence of God or any religious framework. They may be:

• Non-naturalist secular realists (e.g., Parfit, Shafer-Landau), who posit irreducible normative facts without theological grounding.
• Naturalist secular realists (e.g., Railton, Brink), who identify moral properties with natural or social properties accessible to science.

Arguments for secular realism include:

• Claims that normativity can be grounded in reason, human nature, or social practices without appealing to the divine.
• Concerns that linking morality to religion may lead to moral epistemic dependence on contested religious claims.
• The observation that many moral disagreements occur within religious traditions, suggesting that moral reasoning is at least partly autonomous.

14.4 Does Moral Realism Support Theism?

Some philosophers develop moral arguments for the existence of God, contending that:

• The existence of objective moral facts is better explained by a theistic worldview (e.g., C. S. Lewis, more recently some analytic philosophers of religion).
• Theism offers a more satisfying account of moral obligation, value, or human dignity.

Others argue that:

• Moral realism is compatible with both theism and atheism.
• Appealing to God does not resolve key metaethical questions (e.g., about the nature of normativity), but simply relocates them.

Thus, the relationship between religious and secular moral realism is contested, with different views about whether theism is necessary, supportive, or irrelevant to grounding objective moral truths.

15. Moral Realism in Law, Politics, and Human Rights

Moral realism has significant implications for how we think about law, politics, and human rights, where questions of legitimacy, authority, and justice are central.

15.1 Law and Legal Interpretation

In legal philosophy, moral realism underpins some forms of natural law theory and interpretivism:

• Natural law theorists claim that legal validity partly depends on conformity to objective moral standards. An unjust law may lack full legal authority.
• Interpretivists like Ronald Dworkin argue that legal reasoning inherently involves appeals to moral principles (e.g., fairness, equality) that have objective truth-values.

This contrasts with legal positivism, which often separates the existence of law from moral truth, though positivists can themselves be moral realists at the metaethical level.

15.2 Political Legitimacy and Justice

Political philosophers frequently invoke moral realism when justifying:

• Principles of justice (e.g., Rawls’s two principles).
• Norms of equality, freedom, and non-domination.

On realist-friendly interpretations:

• There are objective standards by which political institutions can be judged just or unjust.
• Political legitimacy depends not just on consent or stability but on meeting such standards.

However, some political realists and critical theorists challenge reliance on strong moral realism, suggesting that:

• Politics is fundamentally about power, conflict, and contingency, not about realizing timeless moral truths.
• Claims of objective morality can sometimes mask ideology or entrench existing power relations.

15.3 Human Rights Discourse

Human rights frameworks often presuppose some form of moral realism:

• Rights are typically presented as universal and inalienable, not contingent on local customs or positive law.
• Documents like the Universal Declaration of Human Rights are sometimes interpreted as articulating objective moral claims about the dignity and entitlements of persons.

Realists see this as evidence that international norms aim at stance-independent truths about human worth. Critics, including some relativists and postcolonial theorists, question whether human rights norms are culturally biased or historically contingent.

15.4 Moral Progress, Reform, and Critique

Appeals to moral progress in law and politics—such as:

• The abolition of slavery,
• Expansion of suffrage,
• Decriminalization of certain behaviors,

are often framed in realist terms: these changes are viewed as improvements, not mere shifts in preference. Realists claim that progress language makes most sense if there are objective standards to approximate.

Yet anti-realists propose alternative interpretations:

• Progress may mean increased coherence with our evolving values.
• Or better satisfaction of interests, without positing stance-independent facts.

Moral realism, therefore, provides one influential lens through which to evaluate legal and political institutions, human rights claims, and narratives of reform, while facing competing interpretations from more skeptical or constructivist perspectives.

16. Contemporary Debates and Future Directions

Contemporary work on moral realism is highly diversified, drawing on developments in metaphysics, semantics, epistemology, and empirical research.

16.1 Robust vs. Minimal Realism and Quasi-Realism

Recent debates distinguish between:

• Robust realism, which posits strongly objective, stance-independent moral facts with significant metaphysical and epistemic commitments.
• Minimalism or quasi-realism, associated with philosophers like Simon Blackburn and Allan Gibbard, which seeks to “earn the right” to realist-sounding talk (truth, facts, error) from within an expressivist or noncognitivist framework.

A central issue is whether quasi-realism can replicate all the appearances of realism—genuine disagreement, objectivity, progress—without collapsing into full-blown realism or losing its anti-realist core.

16.2 Metaphysical Innovations: Grounding, Supervenience, and Normative Kinds

Philosophers increasingly use tools such as:

• Grounding and metaphysical dependence to articulate how moral facts relate to non-moral facts.
• Fine-grained distinctions between reduction, realization, and emergence to clarify naturalist and non-naturalist positions.
• Discussions of normative kinds and whether moral properties form a distinctive kind analogous to natural kinds in science.

These developments aim to sharpen the ontological commitments of different realist camps.

16.3 New Epistemological Approaches and Debunking

Ongoing work in moral epistemology explores:

• Refined evolutionary debunking arguments and realist responses.
• The role of phenomenal conservatism (taking appearances as prima facie evidence) in defending moral intuitions.
• The integration of virtue epistemology and models of moral perception.

Future directions include examining whether some moral beliefs can be insulated from debunking while others are revised in light of empirical findings.

16.4 Interdisciplinary and Global Perspectives

Contemporary debates increasingly engage:

• Cross-cultural ethics, questioning whether moral realism can accommodate global moral diversity without ethnocentrism.
• Experimental philosophy, which studies ordinary intuitions about moral objectivity and disagreement.
• Neuroscience of morality, which may inform or challenge assumptions about moral cognition.

There is also growing interest in non-Western philosophical traditions and how they might support or challenge realist frameworks.

16.5 Open Questions

Current and future discussions revolve around questions such as:

• Can a fully naturalistic moral realism preserve robust normativity?
• Is constructivism ultimately a form of realism, anti-realism, or a hybrid?
• How should moral realism address systemic injustice, ideology, and power, which can distort moral perception and discourse?
• What is the best account of moral progress consistent with our historical and empirical understanding?

These and related issues ensure that moral realism remains a central, evolving topic in metaethics and beyond.

17. Legacy and Historical Significance of Moral Realism

Moral realism has played a significant role in shaping both ethical theory and broader intellectual history. Its legacy can be traced through multiple traditions and turning points.

17.1 Continuity Across Historical Periods

From ancient philosophy to the present, many influential thinkers have assumed or defended some form of moral realism:

Despite shifts in metaphysical and epistemological frameworks, the idea that morality might be objectively grounded has remained a recurring theme.

17.2 Influence on Normative Ethics and Political Thought

Moral realism has:

• Supported ambitious normative ethical systems that claim not just coherence but truth (e.g., Kantianism, some versions of consequentialism and virtue ethics).
• Informed theories of justice, rights, and human dignity, which often rely on claims to universal validity.
• Underpinned narratives of moral reform and progress, framing historical changes as movement toward more accurate recognition of moral truths.

Even critics of realism frequently define their positions in opposition to these realist aspirations.

17.3 Shaping Metaethics as a Discipline

The rise of moral realism and its challengers has been central to the formation of metaethics as a distinct field:

• Debates over noncognitivism, error theory, naturalism, and non-naturalism crystallized around the question of whether there are objective moral facts.
• Key concepts such as supervenience, the open-question argument, and the queerness argument became standard tools partly through realist–anti-realist exchanges.

Moral realism thus provided a focal point for clarifying the semantics, metaphysics, and epistemology of moral discourse.

17.4 Broader Cultural and Intellectual Impact

Beyond academic philosophy, realist ideas about moral objectivity have influenced:

• Legal and political institutions, especially in the language of rights, equality, and justice.
• Religious and secular moral education, where the assumption that some actions are truly right or wrong is widespread.
• Public debates on issues like human rights, environmental ethics, and global justice, where appeals to objective moral standards are commonplace.

At the same time, challenges to moral realism have shaped critical perspectives in areas such as genealogy of morals, critical theory, and post-structuralism, which question claims to universal moral truth.

17.5 Ongoing Significance

The historical trajectory of moral realism—its defenses, critiques, and reformulations—continues to inform contemporary discussions about:

• The nature and limits of objectivity in ethics.
• The relationship between values and a scientifically described world.
• How best to understand and evaluate our practices of praise, blame, and moral responsibility.

As such, moral realism remains a central reference point for both historical scholarship and ongoing philosophical inquiry into the foundations of morality.