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Moral Realism


Moral realism is a metaethical view committed to robust objectivity in ethics. No single description is likely to capture all realist views, but a reasonably accurate rule is to understand moral realism as the conjunction of three theses:

The semantic thesis: The primary semantic role of moral predicates (such as "right" and "wrong") is to refer to moral properties (such as rightness and wrongness), so that moral statements (such as "honesty is good" and "slavery is unjust") purport to represent moral facts, and express propositions that are true or false (or approximately true, largely false, and so on).

The alethic thesis: Some moral propositions are in fact true.

The metaphysical thesis: Moral propositions are true when actions and other objects of moral assessment have the relevant moral properties (so that the relevant moral facts obtain), where these facts and properties are robust: their metaphysical status, whatever it is, is not relevantly different from that of (certain types of) ordinary non-moral facts and properties.

To deny any one of these three theses is to embrace some form of moral irrealism. Many philosophers consider moral realism the default position because it appears best to capture many central features of ordinary moral thought: the assertoric surface character of ordinary moral discourse, the phenomenology of moral experience, our claim to have moral knowledge, and the possibility (and nature) of genuine moral error, progress, and disagreement even among sincere, open-minded, and well-informed people (Dancy 1986, Brink 1989, Shafer-Landau 2003).

The semantic thesis is (for better or worse) often associated with the related psychological thesis called cognitivism, according to which the primary role of moral judgments is to express beliefs. One form of irrealism, non-cognitivism, holds that their primary role is to express motivational "non-cognitive" states of mind, such as approving, prescribing, commending, or planning, but can assign moral predicates and judgments a secondary role of referring to (non-moral) properties and expressing (non-moral) beliefs (Copp 2001). How well realists can explain the reliable connection between moral judgment and moral motivation is a matter of some dispute (Smith 1994).

The alethic thesis says that some moral propositions are robustly true only if we combine it with the realist's metaphysical thesis. The irrealists' attitude to the alethic thesis depends on their conception of truth. Error theory accepts a robust reading of the semantic thesis but rejects the alethic thesis on this robust reading. It holds that ordinary moral thought presupposes the existence of robust moral facts and properties but is systematically in error: every moral judgment with existential import is mistaken because there are no robust moral facts to make any such judgment true (Mackie 1977). Non-cognitivist irrealists can accept a non-robust reading of the alethic thesis if they endorse minimalism about truth (but see Dreier 2004). This move may eventually earn them the right to speak of moral facts and truths, and to say all the same things that any morally decent person would say about what is right or wrong, good or bad, just or unjust, and so on, even though they reject the realist's metaphysical thesis (Blackburn 1993).

The metaphysical thesis is central to moral realism because realism is primarily a view about metaphysics, not about truth or semantics. It holds that moral facts and properties are not metaphysically inferior in kind to many ordinary sorts of non-moral facts and properties. What is it for a fact or property to be metaphysically robust, though? One sense in which ordinary non-moral properties are robust is that they enter into explanations of real phenomena; water has its surface properties because it is H2O, for example. In this sense, the realist's metaphysical thesis says that moral properties enter into explanations of phenomena that irrealists would explain by other means (Dreier 2004). An irrealist might take the fact that one believes that inequality is unjust to consist in some such fact as that one has decided to include the reduction of inequality among one's aims. A realist might instead say it consists in standing in a certain belief-like relation to the properties of inequality and injustice. Likewise, the realist might say, whether such a belief is correct or mistaken is just a matter of whether the two properties are related as the belief represents them as being related. The realist's explanation of the assertoric features of ordinary moral discourse, possession of moral knowledge, and nature of moral disagreement would be analogous.

Understanding the metaphysical thesis as above affords one (albeit not the only) way of capturing many realists' conviction that ethics concerns objective matters of fact whose existence and nature are independent of anyone's sentiments, opinions, evidence, or theories about what is right or wrong, obligatory, permissible, or impermissible, good or bad, and so on. So understood, the thesis also classifies as irrealist any view according to which explanations of moral phenomena involve no essential reference to moral facts or properties, but only to such factors as our individual tastes, cultural or social conventions and agreements, basic human sentiments, or the beliefs or plans we would have if we were fully informed and rational. Thus ethical subjectivism, ethical relativism, projectivism, and most forms of constructivism in ethics rightly count as irrealist even though they accept the realist's semantic and alethic theses.

Disputes within the realist camp concern primarily the nature of moral facts and properties. Non-naturalist realists hold that moral properties are robust properties that are distinct from but supervene (see below) on natural properties (Moore 1903, Shafer-Landau 2003). Naturalist realists hold that moral properties are robust natural properties. Reductive naturalists hold that moral properties are identical to natural properties that we can represent in austerely non-moral terms (Railton 1986). Non-reductive naturalists hold that moral properties are an irreducible subclass of the class of natural properties, which we may be unable to represent in austerely non-moral terms (Boyd 1988, Brink 1989).

Arguments for and against different forms of moral realism differ also depending on whether we take true statements of property identity to be analytic (true in virtue of the meanings of their constituent terms) or synthetic, and what we think qualifies a property as natural. If, for example, natural properties are just those that we can investigate empirically, then naturalism will hold that knowledge of any synthetic moral proposition is answerable to empirical evidence, whereas non-naturalism will hold that knowledge of some synthetic moral propositions is empirically indefeasible (Copp 2003, Shafer-Landau 2003). An issue for synthetic naturalists in particular is what determines the reference of moral predicates to the supposedly natural moral properties. Given their view of the matter, can they explain the intelligibility of such "open questions" as whether something that satisfies a given naturalistic non-moral predicate (such as "is pleasant") also satisfies a given moral predicate (such as "is good") (Moore 1903, Horgan and Timmons 1992)?

According to the supervenience argument against moral realism, we can distinguish between a weaker, true claim and a stronger, false claim about the supervenience of the moral on the natural. (Supervenience is a technical name for a relation of necessary covariance.) The alleged problem for the realist is that she cannot, but the irrealist can, explain why the weaker supervenience claim should be true, given that the stronger claim is false (Blackburn 1993). According to one clear version of the argument (Dreier 1992), the true claim is that it is analytically necessary that, for each moral property M that an object O has, there is a (possibly complex) natural property N that O has, and it is metaphysically necessary that M always accompanies N. The stronger, putatively false claim differs in saying that M always accompanies N as a matter of analytic necessity. (Variations of the argument concern predicates rather than properties and involve different types of necessity.) The objection is that if realists are committed to the thesis called "lack of entailment," according to which no set of non-moral naturalistic truths entails any particular moral truth, then they must admit (falsely) that it is possible for M sometimes not to accompany N.

Different forms of moral realism respond differently to the supervenience argument. Analytic naturalists may regard the argument as question-begging, for they deny that the stronger supervenience claim is false (Jackson 1998). Non-naturalists may accept a lack of analytical entailment but claim that duly specified sets of naturalistic truths metaphysically entail particular moral truths because the facts which the former concern exhaustively constitute (in some sense to be explained) the facts which the latter concern (Shafer-Landau 2003). Some synthetic naturalists may say that their theory explains why the weaker supervenience claim is true (since moral properties are natural ones), but entails that no set of non-moral naturalistic truths analytically entails any particular moral truth (since any connection between non-moral and moral truths is synthetic). Others may express doubts as to whether the relevant supervenience claims are formulated so as to make them both interesting and acceptable to synthetic naturalists.

According to the explanatory argument against moral realism, properties of a certain kind are metaphysically robust only if they make a distinctive contribution to our overall explanatory picture of the world (the "explanatory requirement"), but moral properties make no such contribution; therefore, moral properties are not metaphysically robust. A prominent version of this argument claims that mentioning moral properties such as wrongness makes no distinctive contribution to causal explanations of such occurrences as a person's indignation or her judgment "that's wrong" upon seeing some hoodlums set a cat on fire, above and beyond the contribution of mentioning the person's prior beliefs, aversions, and moral principles (Harman 1977). If so, the causal version of the explanatory requirement gives us good reason to deny that there are robust moral facts.

One realist response is to argue that the causal requirement is dubious; for if it is, then it would be no objection to moral realism if moral properties violated that requirement (Shafer-Landau 2003). Moral properties could still play non-causal explanatory roles. A very different response is to accept the causal requirement, but argue that mentioning moral properties can make a distinctive contribution to causal explanations of both intentional occurrences, such as moral judgments, and non-intentional ones (Sturgeon 1988, Brink 1989). On the latter score, one may argue that a person's kindness can cause her to help others or that injustice or oppression can provoke resistance, and that these properties can play such causal-explanatory roles only if they are real, and indeed natural, properties. Here the intricate question arises whether moral properties are epiphenomenal, in that they play no causal-explanatory role over and above the causal-explanatory role of the non-moral properties on which they supervene, or by which they are realized (Miller 2003, Sturgeon 2005).

What unites these debates about moral realism is the concern whether, and how, robust moral facts and properties enter into accounts of various phenomena that irrealists would explain by other means. One general moral may be that arguments in metaethics often are arguments about the best explanation of the phenomena in question. Other important debates between realists and irrealists and within the realist camp concern the rational authority of morality, the extent to which moral realism affords a rational basis for resolving moral disagreements, the existence of an internal connection between moral judgment and moral motivation and whether such "motivational internalism" would make moral properties metaphysically strange, and questions about moral methodology and moral epistemology, such as the place of ethics in a naturalistic worldview and the parity or continuity of ethics with empirical inquiry and the sciences.

See also Ethical Naturalism; Internalism and Externalism in Ethics; Intuitionism, Ethical; Metaethics; Moral Epistemology; Noncognitivism; Objectivity in Ethics; Rationalism in Ethics (Practical Reason Approaches).


Blackburn, Simon. Essays in Quasi-Realism. Oxford: Oxford University Press, 1993.

Boyd, Richard. "How to Be a Moral Realist." In Essays on Moral Realism, edited by Geoffrey Sayre-McCord. Ithaca, NY: Cornell University Press, 1988.

Brink, David O. Moral Realism and the Foundations of Ethics. Cambridge, U.K.: Cambridge University Press, 1989.

Copp, David. "Realist-Expressivism: A Neglected Option for Moral Realism." In Moral Knowledge, edited by Ellen Frankel Paul, Fred D. Miller Jr., and Jeffrey Paul. Cambridge, U.K.: Cambridge University Press, 2001.

Copp, David. "Why Naturalism?" Ethical Theory and Moral Practice 6 (2003): 179200.

Dancy, Jonathan. "Two Conceptions of Moral Realism." Proceedings of the Aristotelian Society, suppl. 60 (1986): 167187.

Dreier, James. "The Supervenience Argument against Moral Realism." Southern Journal of Philosophy 30 (1992): 1338.

Dreier, James. "Meta-ethics and the Problem of Creeping Minimalism." Philosophical Perspectives 18 (2004): 2344.

Harman, Gilbert. The Nature of Morality. Oxford: Oxford University Press, 1977.

Horgan, Terence, and Mark Timmons. "Troubles for New Wave Moral Semantics: The 'Open Question Argument' Revived." Philosophical Papers 21 (1992): 153175.

Jackson, Frank. From Metaphysics to Ethics. Oxford: Oxford University Press, 1998.

Mackie, J. L. Ethics: Inventing Right and Wrong. New York: Penguin, 1977.

Miller, Alexander. An Introduction to Contemporary Metaethics. Cambridge: Polity Press, 2003.

Moore, G. E. Principia Ethica. Cambridge, U.K.: Cambridge University Press, 1903.

Railton, Peter. "Moral Realism." The Philosophical Review 95 (1986): 163207.

Shafer-Landau, Russ. Moral Realism: A Defence. Oxford: Oxford University Press, 2003.

Smith, Michael. The Moral Problem. Oxford: Blackwell, 1994.

Sturgeon, Nicholas L. "Moral Explanations." In Essays on Moral Realism, edited by Geoffrey Sayre-McCord. Ithaca, NY: Cornell University Press, 1988.

Sturgeon, Nicholas L. "Moral Explanations Defended." In Contemporary Debates in Moral Philosophy, edited by James Dreier. Oxford: Blackwell, 2005.

Sturgeon, Nicholas L. "What Difference Does It Make Whether Moral Realism Is True?" Southern Journal of Philosophy, suppl. 24 (1986): 115142.

Wright, Crispin. "Realism, Antirealism, Irrealism, Quasi-Realism." Midwest Studies in Philosophy 12 (1988): 2549.

Pekka Väyrynen (2005)

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Realism, Moral

Realism, Moral


Moral realism is the doctrine that some moral claims are true in a way that is independent of their being endorsed, or regarded as true, by any human being. Consider, for instance, the claim that torturing babies for the sole purpose of deriving sadistic pleasure is immoral. Moral realists would regard this claim as true. But that itself does not distinguish the moral realist from many other moral theorists. What is distinctive about the moral realist is that the truth of this claim in no way depends on the attitudes that people take toward the claim itself. It is not true because one believes it or because society endorses it. For the moral realist, the standards that determine whether moral claims are true or false are as objective as those that determine the accuracy of claims in logic or the natural sciences.

All moral realists will accept that an actions rightness depends to some extent on the circumstances in which one is situated. That is because, for the realist, the correct standards of morality may well dictate different actions, depending on the circumstances. In some cases, for instance, it is morally acceptable to cut into the flesh of human beingsfor instance, during surgery. But in other cases, such action is impermissible, because it is being done in the name of coercion or humiliation. What is centrally important for the moral realist is that attitudes about what is right and wrong do not determine what really qualifies as such. Even the most cherished moral beliefs might be mistaken, because their authority does not depend on an endorsement of them.

Moral realists qualify as cognitivists. Cognitivists are theorists who conceive of moral judgments in terms of their cognitive content and function. Cognitivists regard moral claims as capable of truth or falsity, and conceive of the function of moral discourse to be that of attempting to describe the nature of moral reality. This differs from noncognitivists, who consider moral judgments to be primarily expressions of emotions or commitments, and, thus, incapable of being either true or false.

Error theorists, like moral realists, accept cognitivism. But error theorists deny that there is any moral reality awaiting discovery. In rendering sincere moral judgments, one is indeed trying to state the truth about what is moral and immoral. But there is, according to error theorists, no such truth. Therefore, all fall into error when issuing moral judgments. Perhaps the most illuminating analogy here is that of the atheist, who regards theistic discourse as intended to describe an objective, divinely ordered reality. But, from the atheists perspective, there is no such reality, and so all theistic discourse is riddled with error.

Moral realism should also be distinguished from ethical relativism. The relativist is also a cognitivist, and so believes that moral judgments are capable of truth and falsity. Unlike the error theorist, the relativist thinks that some moral claims are true. But they are true only because they accurately capture the implications of different social agreements. The realist and the relativist differ, in other words, on the ultimate source of correct moral standards. For the relativist, moral standards are correct because they are endorsed by various groups of human beings. For the moral realist, human endorsement is not the ultimate authority in morality.

In psychological circles, moral realism is often associated with the work of the Swiss psychologist Jean Piaget (1896-1980), who attributed a belief in it to very young children. In Piagets hands, moral realism stands for the idea that there are objectively correct moral rules that are never permissibly broken, such that failure to adhere to them is always morally blameworthy. Neither of these latter implications is essential to the doctrine as it is currently discussed within the philosophical community.

SEE ALSO Morality; Objectivism; Relativism


Brink, David. 1989. Moral Realism and the Foundations of Ethics. Cambridge, U.K.: Cambridge University Press.

Piaget, Jean, and Bärbel Inhelder. 1969. The Psychology of the Child. Trans. Helen Weaver. New York: Basic Books.

Sayre-McCord, Geoffrey, ed. 1988. Essays on Moral Realism. Ithaca, NY: Cornell University Press.

Shafer-Landau, Russ. 2003. Moral Realism: A Defence. Oxford: Oxford University Press.

Smith, Michael. 1995. The Moral Problem. Oxford: Blackwell.

Russ Shafer-Landau

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