Naturalistic Fallacy

1. Introduction

The naturalistic fallacy is a term introduced by G. E. Moore in 1903 to label what he took to be a characteristic mistake in ethical theory: the attempt to define the moral property of good in terms of some other property, typically a natural or otherwise purely descriptive property such as pleasure, desire‑satisfaction, evolutionary fitness, or what God wills. On Moore’s view, this move wrongly treats “good” as analyzable, like “bachelor” as “unmarried man,” rather than as a simple, indefinable property.

The topic occupies a central place in metaethics, the part of moral philosophy concerned with the nature of moral properties and the meaning of moral language. Discussions of the naturalistic fallacy commonly intersect with debates about:

• Whether moral properties are reducible to natural properties (ethical naturalism)
• Whether moral properties are sui generis and non‑natural (non‑naturalist moral realism)
• The relation between descriptive claims about the world and normative or evaluative claims

Moore’s charge has been especially influential because he linked it with a distinctive line of reasoning, the Open Question Argument, which aims to show that any purported definition of “good” in natural terms leaves an intelligible question open: “X has that property, but is X good?” This is taken to indicate a conceptual gap between moral and natural predicates.

Subsequent philosophers have debated whether there is a genuine fallacy involved, whether Moore’s diagnosis rests on a mistaken view of language, and how far his critique reaches. Some accept his warning against simplistic reductions while rejecting his non‑naturalism; others defend various forms of naturalism that seek to avoid his objections.

The naturalistic fallacy has therefore served as a focal point for organizing and criticizing theories of value, shaping twentieth‑ and twenty‑first‑century discussions of moral realism, moral language, and the autonomy (or otherwise) of ethics from empirical science and religion.

2. Origin and Attribution

The expression “naturalistic fallacy” is most closely associated with G. E. Moore and is generally attributed to him as a term of art in metaethics. Moore introduced and popularized the phrase in Principia Ethica (1903), where he used it to criticize leading moral theories of the nineteenth century.

Moore’s Coinage

Moore explicitly labels as fallacious any attempt to define “good” by identifying it with some natural or metaphysical property. In Principia Ethica §10, he writes:

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It may be true that all things which are good are also something else, just as it is true that all things which are yellow produce a certain kind of vibration in the light. And it is a fact, that Ethics aims at discovering what are those other properties belonging to all things which are good. But far too many philosophers have thought that when they named those other properties they were actually defining good.

— G. E. Moore, Principia Ethica (1903)

Here Moore both introduces the critical label and explains that his target is a confusion of definition rather than merely a false substantive theory.

Pre‑Moorean Antecedents

Although the term itself is Moore’s, some historians trace conceptual antecedents in earlier authors:

Most commentators, however, emphasize that these anticipations are retrospective reconstructions; none of these figures used the label “naturalistic fallacy,” and they often pursued very different projects.

Early Reception and Attribution

Early twentieth‑century discussions in analytic philosophy rapidly adopted Moore’s terminology. Authors such as W. D. Ross, C. D. Broad, and later W. K. Frankena engaged directly with “the naturalistic fallacy” as Moore’s distinctive contribution. Some critics have argued that what Moore called a “fallacy” is more properly a controversial metaethical thesis than a logical error, but they still treat the label as Moore’s coinage.

Subsequent uses of “naturalistic fallacy” in other disciplines (e.g., evolutionary ethics, sociobiology, and popular moral reasoning) typically trace back, directly or indirectly, to Moore’s 1903 formulation.

3. Historical Context and Intellectual Background

Moore’s articulation of the naturalistic fallacy emerged within a specific late nineteenth‑ and early twentieth‑century setting, marked by shifting views in ethics, metaphysics, and the philosophy of language.

Reactions against Victorian Ethical Theories

Moore was reacting to influential nineteenth‑century attempts to ground ethics in naturalistic or quasi‑scientific terms:

Moore interpreted these theories as offering reductive analyses of “good,” not merely substantive claims about which things are in fact good.

Emergence of Analytic Philosophy

The naturalistic fallacy is tied to the early analytic turn in philosophy:

• Moore’s contemporaries, including Bertrand Russell, were focused on clarifying meanings and logical form.
• In ethics, this encouraged a distinction between:
  • Questions about what is good (first‑order ethics)
  • Questions about what “good” means and what kind of property it denotes (metaethics)

Moore’s project fits this new emphasis on linguistic and conceptual analysis, even though he retained an intuitionist metaphysics of value.

Intuitionism and British Moral Philosophy

Moore also drew on a British intuitionist tradition (e.g., Sidgwick) that treated some moral truths as self‑evident. This provided a background for his claim that goodness is:

• A real property
• Known, at least in part, by intuition
• Not analyzable into non‑moral concepts

The naturalistic fallacy, in Moore’s presentation, is thus one way of denying the irreducible character of the moral.

Scientific Naturalism and Positivist Currents

Turn‑of‑the‑century intellectual life was also marked by growing confidence in science and various forms of naturalism:

• Evolutionary theory suggested that moral behavior might be explained biologically.
• Some thinkers inferred that what is morally right just is what is biologically or socially adaptive.

Moore’s critique is situated against this wider backdrop of increasing attempts to give ethics a scientific foundation, which he interpreted as a threat to the distinctiveness of moral value.

4. Moore’s Formulation of the Naturalistic Fallacy

In Principia Ethica, Moore presents the naturalistic fallacy as a specific type of conceptual confusion about the meaning of “good.” His central claim is that “good” denotes a simple, indefinable property and that attempts to define it in terms of any other property are mistaken.

Definition and Core Claim

Moore states that many ethical philosophers have:

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...committed what I call the naturalistic fallacy; and if I am right, it is the chief and most prevalent of all the mistakes in the reasoning of moral philosophers.

— G. E. Moore, Principia Ethica (1903)

The error, as he characterizes it, involves treating a statement of the form:

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“Good” = “N”

(where N is some natural or descriptive predicate, such as “pleasant,” “desired,” or “more evolved”) as a genuine definition or analytic identity. Moore argues that such identifications:

1. Confuse co‑extension (everything good may be pleasant) with identity of meaning (goodness is the same concept as pleasure).
2. Overlook the distinctive normative role of “good” in moral discourse.

Scope of the “Fallacy”

Moore’s label is broader than the word “naturalistic” may suggest. He applies it to:

• Naturalistic reductions, such as “good” = “what we desire to desire.”
• Metaphysical or theological reductions, such as “good” = “what God wills” or “what is real.”

For Moore, the common feature is not the type of property, but the claim of definitional identity between “good” and some other predicate.

Illustrative Examples

Moore frequently targets hedonistic definitions:

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When we say that pleasure is the only good, we do not mean that ‘good’ is identical with ‘pleasant’.

— paraphrased from Principia Ethica

He maintains that even if pleasure is the only thing that is in fact good, it would still be an error to infer that “good” means “pleasure.”

Similarly, he criticizes some forms of evolutionary ethics that infer:

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“More evolved” = “better”

on the basis of correlations between evolutionary progress and what people value, treating this as a definition rather than a contingent claim about what tends to be good.

Role within Moore’s Project

Moore’s formulation of the naturalistic fallacy is integral to his broader metaethical program:

• It clears the way for his view that goodness is a non‑natural property.
• It supports his reliance on intuition to grasp the meaning and instantiation of “good.”
• It motivates the need for a careful distinction between descriptive and evaluative components of ethical claims, even when they are closely connected.

5. The Open Question Argument

The Open Question Argument (OQA) is Moore’s primary tool for supporting his claim that defining “good” in naturalistic terms is mistaken. It is designed to show that, for any proposed definition of “good” in descriptive terms, a certain type of question remains intelligible and substantive, suggesting that “good” is not identical in meaning to the descriptive predicate.

Structure of the Test

Moore’s method can be summarized as follows:

1. Take a proposed definition of “good” in terms of some property N (e.g., “good” = “pleasant”).
2. Consider the question:
   “X is N, but is X good?”
3. Ask whether this question is open (genuinely disputable and not trivially answerable) or closed (equivalent to “X is N, but is X N?”).

Moore asserts that, for every such proposed definition, the corresponding question remains open, thereby indicating that the supposed identity is not analytic.

Examples Moore Emphasizes

Moore applies the argument to several prominent candidates:

He insists that competent speakers can make sense of such questions without contradiction, which he takes to show that the concept of good is distinct from any proposed naturalistic analysis.

Relation to Ordinary Moral Reasoning

Moore presents the OQA as capturing an aspect of ordinary moral reflection:

• People often fully understand the natural facts about a situation (pleasure, desires, evolutionary outcomes) yet still find it meaningful to ask whether the situation is good.
• The persistent sense that value questions remain unsettled even when descriptive facts are known is used to motivate the claim that “good” has an irreducible meaning.

Meta‑Linguistic Focus

The Open Question Argument targets the semantic relation between moral and natural terms rather than directly engaging with metaphysical issues about what properties exist. It is framed as an argument about:

• Meaning and conceptual analysis (“What does ‘good’ mean?”)
• The limits of definition by reduction to other predicates

Moore uses its conclusion—that “good” cannot be analytically identified with any natural predicate—to support his broader claims about the nature of moral properties and the alleged naturalistic fallacy.

6. Logical Structure of the Argument

Moore’s overall case against naturalistic definitions of “good” combines the naturalistic fallacy diagnosis with the Open Question Argument. Contemporary reconstructions typically present this case in a more explicitly logical form than Moore himself used.

Core Schema

A common formulation models Moore’s reasoning roughly as:

1. If “good” were analytically identical to some natural predicate N,
   then the question “X is N, but is X good?” would be closed or trivial.
2. For any proposed N (pleasant, desired, more evolved, etc.), the question “X is N, but is X good?” is open and substantive.
3. Therefore, for any such N, “good” is not analytically identical to N.
4. Attempts to define “good” as any such N therefore commit a conceptual mistake (the naturalistic fallacy).

Elements of the Logical Framework

This structure relies on several background assumptions:

From a logical point of view, the argument has the form of a reductio: assume that “good” is definable as N, derive a consequence (the closed‑question status) that conflicts with intuitive linguistic data (the question remains open), and conclude that the assumption is false.

Distinguishing Semantic from Metaphysical Claims

Later commentators underscore that Moore’s argument, so reconstructed, is primarily about semantic equivalence, not about metaphysical identity of properties. The key inferential move is:

• From “the question about good vs. N is open”
  to “the terms ‘good’ and ‘N’ do not have the same meaning.”

This leaves room, at least in principle, for positions that deny any analytic identity but still explore synthetic or a posteriori identifications, an issue taken up in subsequent debates.

Status of the Inference

Moore treats the transition from the openness of questions to non‑identity of meanings as secure. Later critics have questioned whether this step is logically valid or whether it rests on controversial assumptions about how ordinary linguistic intuition tracks analyticity. These challenges concern the soundness rather than the basic validity of the reconstructed argument form, which most commentators regard as structurally coherent.

7. Targets: Forms of Ethical Naturalism

The naturalistic fallacy, as Moore describes it, is primarily directed against various forms of ethical naturalism that identify moral properties, especially goodness, with natural or otherwise descriptive properties. His critique ranges across several distinct target views.

Hedonistic and Utilitarian Reductions

Moore most explicitly confronts hedonistic theories, especially classical utilitarianism:

Moore construes these not merely as claims about what is in fact good, but as analytic definitions that reduce the meaning of “good” to pleasure or desire‑satisfaction.

Evolutionary Ethics

Another major target is evolutionary ethics, especially in the work of Herbert Spencer. Moore interprets Spencer as suggesting that:

• What is more evolved, more adapted, or conducive to survival and progress just is what is good.

On Moore’s reading, this amounts to defining “better” as “more evolved” and is taken to exemplify the naturalistic fallacy by collapsing evaluative notions into evolutionary descriptions.

Desire‑ and Preference‑Based Theories

Moore also addresses variants of ethical naturalism that ground value in:

• Actual desires or preferences (what people in fact want)
• Idealized desires (what we would desire under certain rational or informed conditions)

He construes these as treating “good” as identical to some function of human motivation, thereby attempting to explain away the distinctive normativity of moral judgments.

Theological and Metaphysical Reductions

Although his label is “naturalistic,” Moore extends the charge to some non‑natural or theological accounts:

Moore argues that these also attempt an illicit definition of “good” in terms of another predicate, even if that predicate is not empirically natural.

Distinguishing Substantive from Analytic Theories

It is important in interpreting Moore’s targets to distinguish:

• Substantive moral theories that claim, for example, that pleasure is the only thing that is in fact good, from
• Analytic definitions that claim “good” means “pleasure”.

Moore reads many historical naturalists as making (or implicitly relying on) the latter, and thus as committing the naturalistic fallacy. Some later commentators question whether these targets were in fact committed to such strong definitional claims, but Moore’s critique is framed against them in this more ambitious sense.

8. Goodness as a Non‑Natural and Indefinable Property

Central to Moore’s deployment of the naturalistic fallacy is his positive claim that goodness is a non‑natural, simple, and indefinable property. This view underpins his rejection of naturalistic reductions.

Simplicity and Indefinability

Moore holds that “good” denotes a property that is:

• Simple: it cannot be analyzed into or constructed from other more basic concepts.
• Indefinable: no set of descriptive or evaluative predicates can capture its meaning through analytic equivalence.

He compares “good” to “yellow”:

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Good is good, and that is the end of the matter; or if I am asked “How is good to be defined?” my answer is that it cannot be defined, and that is all I have to say about it.

— G. E. Moore, Principia Ethica (1903)

Just as one can point to yellow things without defining “yellow” in more basic terms, one can recognize instances of goodness without a further conceptual reduction.

Non‑Natural Property

Moore characterizes goodness as non‑natural:

“Non‑natural” in Moore’s sense does not necessarily mean supernatural or mysterious; it denotes a category of properties that are not accessible solely by empirical methods.

Intuitive Grasp of Goodness

Moore contends that we have direct cognitive access to the property of goodness via moral intuition:

• When we contemplate certain states of affairs (e.g., friendship, aesthetic appreciation), we allegedly “see” their goodness.
• This intuitive awareness underwrites basic moral judgments and, for Moore, provides evidence that the property is irreducible.

This intuitionist element is tightly linked to the claim that definitions in non‑moral terms are misguided.

Relation to Other Properties

Although goodness is non‑natural and indefinable, Moore allows that it can be:

• Co‑instantiated with natural properties (e.g., pleasurable experiences might always be good).
• Correlated with them in lawful or explanatory ways.

However, he insists that such correlations do not entail analytic identity. Goodness, as he conceives it, supervenes on natural facts in the sense that no change in goodness is possible without some change in the underlying descriptive facts, but it is not reducible to those facts in conceptual or metaphysical terms as he understands them.

9. Relation to Hume’s Is–Ought Gap

Moore’s naturalistic fallacy is often associated with David Hume’s thesis that one cannot derive an “ought” from an “is,” but the two ideas concern distinct, though related, issues.

Hume’s Is–Ought Thesis

In A Treatise of Human Nature, Hume observes that some moralists move from purely descriptive statements to normative conclusions without explanation:

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In every system of morality, which I have hitherto met with, I have always remark’d, that the author proceeds for some time in the ordinary way of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when of a sudden I am surpriz’d to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not.

— David Hume, Treatise of Human Nature, Book III

Hume’s point is logical: a valid inference to an “ought” requires at least one normative premise.

Moore’s Distinct Focus

Moore’s naturalistic fallacy, by contrast, is about definition and meaning:

• He claims that identifying “good” with any natural predicate (e.g., “pleasant”) is a semantic error.
• The focus is not primarily on inference patterns but on conceptual analysis of moral terms.

Thus, while Hume questions certain transitions from descriptive premises to normative conclusions, Moore questions claims of analytic equivalence between normative and descriptive predicates.

Similarities and Overlaps

Despite these differences, some structural affinities are often noted:

Many commentators suggest that Moore’s refusal to equate “good” with natural properties echoes Hume’s insistence that value claims cannot be straightforwardly derived from factual claims.

Later Conflation and Clarifications

In later literature and popular usage, “naturalistic fallacy” has sometimes been used as if it were simply another name for Hume’s is–ought point. Philosophers typically treat this as a misconception:

• Hume did not use the term “naturalistic fallacy.”
• Moore’s argument targets analytic definitions rather than deductive inferences.

Subsequent work in metaethics often emphasizes this distinction, while acknowledging that both Hume and Moore contribute, in different ways, to the idea that normative discourse cannot be collapsed into purely descriptive discourse without loss or error.

10. Standard Objections and Critiques

Moore’s diagnosis of the naturalistic fallacy and his Open Question Argument have generated extensive critical discussion. Several standard objections have become canonical in the metaethical literature.

Conflation with the Open Question Argument

One influential line of critique, developed by W. K. Frankena, holds that Moore’s talk of a “naturalistic fallacy” adds little beyond the Open Question Argument itself:

• The alleged “fallacy” is not a distinctive logical error but simply the failure to accept Moore’s semantic thesis.
• The rhetorical label may obscure that Moore is advancing a substantive view about the meaning of “good,” not identifying a formal fallacy.

On this reading, what Moore calls a “fallacy” is arguably just disagreement with his own analysis.

Question‑Begging and the Role of Intuition

Another criticism, associated with R. M. Hare, John Searle, and others, targets the Open Question Argument’s reliance on intuitive judgments about what questions feel “open”:

• It is argued that ordinary speakers’ sense that “Pleasure is present, but is it good?” is a substantive question does not entail that “good” and “pleasure” are not analytically identical.
• Historical examples such as “Water is H2O” are cited: it once seemed an open question whether water was H2O, yet this is now treated as a necessary identity discovered empirically.
• Critics contend that Moore begs the question by assuming that analytic identities must be transparent to competent speakers.

Semantic vs. Metaphysical Ambiguity

A further objection, pressed by Nicholas Sturgeon, Peter Railton, and other moral naturalists, claims that Moore’s argument equivocates between semantic and metaphysical questions:

On this view, Moore’s reasoning, at best, undercuts simplistic analytic reductions, but not more sophisticated metaphysical naturalisms.

Misuse of “Fallacy” and Confusion with Is–Ought

Some critics argue that Moore’s use of the word “fallacy” is misleading:

• A fallacy is usually a pattern of invalid inference, whereas Moore’s complaint concerns substantive metaethical identifications.
• The label has contributed to the widespread confusion between Moore’s view and Hume’s is–ought point, despite their distinct targets.

These critics suggest that speaking instead of a “Moorean challenge” or “Moorean argument” would avoid implying that naturalistic theories are formally illogical.

Scope and Historical Accuracy

Another set of objections questions whether Moore’s historical targets actually held the strong analytic definitional theses he attributes to them:

• Some interpreters of Mill, Sidgwick, or Spencer claim that these authors offered substantive axiological claims rather than strict analyses of “good.”
• If so, Moore’s charge of a naturalistic fallacy may misrepresent important predecessors and overstate the prevalence of the alleged mistake.

These and related critiques shape later reformulations of Moore’s insights and motivate alternative metaethical frameworks.

11. Responses, Revisions, and Clarifications

In response to the standard objections, philosophers have offered a variety of refinements and reinterpretations of Moore’s naturalistic fallacy and Open Question Argument, aiming either to defend them in modified form or to preserve some of their insights while rejecting others.

Distinguishing Multiple Theses in Moore

Many commentators now separate Moore’s position into distinct components:

Some responses concede that the semantic thesis may have force against certain analytic reductions while questioning whether it entails Moore’s metaphysical non‑naturalism or justifies the strong “fallacy” language.

Reinterpretation as Anti‑Reductionist Constraint

One influential revision treats Moore’s contribution not as a refutation of naturalism, but as an anti‑reductive constraint on theories of value:

• Ethical theories should not simply define away moral concepts in descriptive vocabulary.
• Instead, they must respect the distinctive roles that moral predicates play in reasoning, motivation, and deliberation.

On this view, Moore’s key insight is preserved as a warning against conceptual oversimplification, without committing to non‑natural properties.

Responses from Moral Naturalists

Contemporary moral naturalists have developed positions designed to be consistent with a modified Moorean insight:

• Some accept that there is no analytic identity between “good” and any natural term, but propose a posteriori identity claims between moral and natural properties (e.g., Railton, Sturgeon).
• Others adopt reductionist projects that treat moral properties as higher‑level natural properties characterized by their causal‑explanatory roles rather than by definitional equivalence.

These responses typically argue that Moore’s semantic premises do not rule out metaphysical identifications discovered through empirical or theoretical investigation.

Non‑Reductive and Quasi‑Naturalist Approaches

A different set of responses emphasize supervenience and non‑reductive relations:

• Moral properties are held to supervene on natural properties: no moral difference without a natural difference.
• However, moral vocabulary is seen as autonomous in its normative function and not definable in purely descriptive terms.

Such positions, often called quasi‑naturalism, aim to retain Moore’s insight about the irreducibility of moral language while avoiding commitment to sui generis, robustly non‑natural properties.

Pedagogical and Heuristic Reinterpretations

Finally, some philosophers suggest that the best way to understand Moore’s “naturalistic fallacy” is as a pedagogical heuristic:

• It highlights the need to distinguish descriptive from evaluative content.
• It encourages careful attention to conceptual analyses in ethics.

Under this reinterpretation, the label “fallacy” is not taken literally, but the framework remains a useful tool for structuring debates about moral language and value.

12. Impact on Metaethics and Moral Realism

Moore’s discussion of the naturalistic fallacy has had a lasting impact on metaethics, particularly on debates about moral realism, the status of moral properties, and the analysis of moral language.

Shaping the Metaethical Agenda

Moore’s work helped consolidate metaethics as a distinct domain by foregrounding questions such as:

• What does “good” mean?
• What sort of property, if any, does “good” denote?
• How, if at all, are moral properties related to natural properties?

Subsequent metaethical theories often define themselves partly in relation to Moore’s framework, either by endorsing, modifying, or rejecting his central claims.

Influence on Non‑Naturalist Moral Realism

Moore is a key early figure in non‑naturalist moral realism:

Later non‑naturalists, such as W. D. Ross and some contemporary realists, draw on Moore’s insistence that moral facts cannot be fully captured in the vocabulary of the natural sciences.

Stimulating Alternative Realist Positions

Moore’s arguments also stimulated the development of naturalist versions of moral realism:

• Moral naturalists sought to preserve realism about moral facts while avoiding Moore’s objection by adopting more sophisticated understandings of reduction, identity, and explanation.
• The critique of the naturalistic fallacy spurred naturalists to distinguish between analytic and synthetic reductions and to develop accounts of how moral properties might figure in causal and explanatory roles.

Thus, Moore’s challenge indirectly shaped the methodology of naturalist moral realism.

Contributions to Noncognitivism and Expressivism

The naturalistic fallacy also influenced noncognitivist and expressivist accounts of moral language:

• Thinkers such as A. J. Ayer and R. M. Hare took Moore’s difficulties for naturalistic definitions as support for the idea that moral terms do not primarily describe properties at all.
• Instead, moral language is seen as expressing attitudes, prescriptions, or plans, bypassing the need to identify goodness with any natural (or non‑natural) property.

Although these theories diverge sharply from Moore’s realism, they share his resistance to straightforward descriptive reductions.

Clarifying Supervenience and Autonomy

Moore’s separation of moral from natural properties fed into later discussions of moral supervenience and the autonomy of ethics:

• Many contemporary philosophers, including those who reject Moore’s non‑naturalism, accept that moral facts are in some sense dependent on but not identical with natural facts.
• The naturalistic fallacy debate provided an early platform for articulating these subtle relations, which now occupy a central place in metaethical theorizing.

Overall, the naturalistic fallacy has functioned less as a settled doctrine and more as a reference point around which competing views of moral realism and the nature of ethical discourse have been organized.

13. Alternative Naturalist and Non‑Naturalist Frameworks

In the wake of Moore’s critique, philosophers have developed a range of alternative frameworks for understanding the relation between moral and natural properties, both within naturalism and non‑naturalism.

Sophisticated Moral Naturalism

Some naturalists accept Moore’s challenge to analytic reductions while defending metaphysical reductions:

These frameworks aim to reconcile realism and naturalism while explaining why moral/natural identities might not be transparent to ordinary intuition.

Non‑Reductive and Quasi‑Naturalist Views

Other theorists adopt non‑reductive or quasi‑naturalist approaches:

• Moral properties are said to supervene on natural properties but are not reducible to them in terms of definitions or strict identities.
• Moral vocabulary is treated as autonomous, serving distinctive normative functions that are not captured by descriptive language.

Such views often emphasize continuity with scientific understanding while resisting Moore’s commitment to sui generis, non‑natural properties.

Contemporary Non‑Naturalist Realisms

Beyond Moore, several contemporary philosophers defend more elaborated forms of non‑naturalist moral realism:

These frameworks frequently refine Moore’s position by clarifying how non‑natural properties can fit into a broader metaphysical picture without violating naturalistic constraints on causation or explanation.

Expressivist and Constructivist Alternatives

Although not straightforwardly naturalist or non‑naturalist about properties, expressivist and constructivist accounts offer alternatives to Moore’s property‑focused framework:

• Expressivists (e.g., noncognitivists, quasi‑realists) view moral language as expressing attitudes or practical stances rather than reporting properties, thereby sidestepping the issue of natural vs. non‑natural moral properties.
• Kantian constructivists (e.g., Korsgaard) see moral truths as constructed from the standpoint of rational agency or practical reason, rather than discovered as natural or non‑natural facts.

These approaches reframe the debate in terms that differ significantly from Moore’s, though they respond, in part, to the issues his work raised about reduction, meaning, and normativity.

14. Connections to Contemporary Moral Psychology and Science

Moore’s concern about defining “good” in naturalistic terms has ongoing relevance for debates at the intersection of moral philosophy, psychology, and the natural sciences.

Evolutionary Explanations of Morality

Contemporary evolutionary psychology and sociobiology offer accounts of moral behavior in terms of:

• Fitness advantages, cooperation, and kin selection
• The evolution of moral emotions such as guilt, shame, and empathy

These explanations often raise the question of whether what has evolved is therefore good. Moore’s critique is frequently invoked to caution against inferring normative conclusions directly from evolutionary success, which would resemble the type of move he criticized in Spencer.

Neuroscience and Moral Cognition

Advances in neuroscience have investigated the brain processes involved in moral judgment and decision‑making:

While these findings illuminate how people make moral judgments, Moore’s framework highlights the question of whether such descriptive accounts can fully capture or replace the normative concept of “good.”

Moral Psychology and Normativity

Research in cognitive science and social psychology explores phenomena such as:

• Moral heuristics and biases
• Cultural variation in moral norms
• Developmental trajectories of moral reasoning

Some theorists argue that moral facts are, or should be, understood in terms of psychological states and their functions. Others invoke Moore’s concerns to argue that even a complete psychological description of our moral practices would leave open the question of whether the states described are genuinely good or justified.

Naturalistic Programs and Moorean Constraints

Contemporary naturalistic programs in ethics often aim to integrate empirical findings with normative theorizing while being sensitive to Moorean worries:

• They may accept that “good” is not analytically definable in scientific terms but maintain that moral norms can be informed and constrained by empirical knowledge about human flourishing, needs, or well‑being.
• Moore’s naturalistic fallacy is sometimes invoked to distinguish between using science to inform ethics and reducing ethics to science.

In this way, debates about the naturalistic fallacy continue to shape how philosophers and scientists conceptualize the relationship between descriptive moral psychology and normative ethical theory.

15. Pedagogical Role and Misconceptions

In contemporary philosophy education, the naturalistic fallacy often functions as a teaching tool as much as a contested theoretical claim. Its pedagogical role is accompanied by several common misunderstandings.

Pedagogical Uses

In introductory ethics and metaethics courses, instructors frequently use Moore’s idea to:

In these contexts, the naturalistic fallacy functions as a heuristic warning against conflating descriptive and normative dimensions of ethical discourse.

Common Misconceptions

Several misconceptions frequently arise in both classroom and popular discussions:

1. Equating the naturalistic fallacy with Hume’s is–ought gap
   Many assume that Moore’s point is simply that one cannot deduce an “ought” from an “is.” Philosophers typically stress that Moore’s focus is on definition, not inference, and that Hume’s and Moore’s claims are distinct.

2. Thinking Moore rejects any role for facts in ethics
   It is sometimes inferred that, if defining “good” in natural terms is a fallacy, factual considerations are irrelevant to moral evaluation. Moore himself allows rich connections between natural facts and goodness; his claim concerns conceptual identity, not evidential irrelevance.

3. Treating all appeals to nature as fallacious
   The term “naturalistic fallacy” is often used loosely to criticize any argument that mentions what is natural. In Moore’s sense, the alleged fallacy specifically involves the analytic identification of “good” with some natural predicate, not every reference to nature in moral reasoning.

4. Assuming the fallacy is a formally recognized logical error
   Some students take “naturalistic fallacy” to be on a par with formal fallacies like affirming the consequent. Many philosophers, however, regard it as a controversial metaethical judgement, not a universally accepted logical rule.

Clarifying the Concept in Teaching

To mitigate these misunderstandings, instructors often:

• Emphasize the difference between semantic reduction and empirical relevance.
• Present both Moore’s original formulations and standard critiques, allowing students to see the status of the naturalistic fallacy as philosophically contested.
• Use examples from contemporary debates (e.g., evolutionary ethics, well‑being research) to show how Moore’s concerns can inform, but not automatically settle, questions about the role of natural facts in moral theory.

16. Legacy and Historical Significance

The notion of the naturalistic fallacy has had a significant and evolving legacy within twentieth‑ and twenty‑first‑century philosophy, influencing not only metaethics but also broader conceptions of the relationship between ethics, language, and science.

Early Influence in Analytic Philosophy

In the first half of the twentieth century, Moore’s discussion helped shape the emerging tradition of analytic philosophy:

Moore’s terminology and arguments became standard reference points in debates about the status of moral properties.

Interaction with Logical Positivism and Noncognitivism

The naturalistic fallacy also set the stage for responses from logical positivists and noncognitivists:

• Figures such as A. J. Ayer accepted the difficulty of reducing “good” to natural terms but concluded that moral statements are expressions of emotion rather than assertions of fact.
• Later expressivists and prescriptivists built on both Moore’s critique of naturalistic definitions and the positivist emphasis on verification, leading to new, influential accounts of moral discourse.

In this way, Moore’s work indirectly contributed to anti‑realist strands in metaethics, even though he himself was a realist.

Mid‑ to Late‑Twentieth‑Century Reassessment

From the mid‑twentieth century onward, philosophers reassessed Moore’s contribution:

• Critics argued that the naturalistic fallacy, as Moore conceived it, is not a formal fallacy and that his Open Question Argument may rest on questionable assumptions about language and analyticity.
• At the same time, the debate catalyzed more nuanced accounts of reduction, supervenience, and a posteriori identity, shaping the development of moral naturalism and non‑reductive views.

The label “naturalistic fallacy” thus became a focal point around which competing theories articulated their understanding of the fact–value relationship.

Continuing Role in Contemporary Thought

In contemporary philosophy, the naturalistic fallacy is often regarded as having primarily heuristic and historical significance:

• Many metaethicists now treat Moore’s challenge as a starting point for inquiry rather than a decisive refutation of naturalism.
• The concept still plays a role in interdisciplinary debates—for example, when assessing claims that evolutionary success, psychological health, or neural patterns constitute moral goodness.

Despite widespread criticism of Moore’s specific arguments, the naturalistic fallacy remains a standard reference in discussions about the autonomy of ethics, the analysis of moral language, and the limits of scientific and religious explanations of value. Its enduring presence reflects its historical importance in setting the agenda for much of twentieth‑century metaethics and in framing ongoing questions about how moral concepts relate to the natural world.