Open Question Argument

1. Introduction

The Open Question Argument is a central episode in 20th‑century metaethics, associated primarily with G. E. Moore’s claim that moral predicates such as ‘good’ cannot be defined in purely naturalistic or descriptive terms. It uses a seemingly simple linguistic test: whenever philosophers offer a definition of ‘good’—for example, as pleasure, desire‑satisfaction, or evolutionary fitness—it appears that competent speakers can still intelligibly ask, “Yes, but is that property really good?” Moore took this persistence of an “open question” to reveal a fundamental gap between normative and natural properties.

The argument functions at the intersection of ethics, philosophy of language, and metaphysics. It is not primarily a claim about which things are good, but about what ‘good’ means and about the ontological status of moral properties. Proponents have used it to defend non‑naturalist moral realism and to criticize ethical naturalism and other reductive accounts of value. Critics have challenged both its underlying assumptions about meaning and its inference from facts about language to claims about moral reality.

In contemporary discussion the Open Question Argument is often treated as a family of related ideas rather than a single, precisely formulated proof. These ideas include:

• a conceptual test for proposed analytic definitions of moral terms
• the charge of a naturalistic fallacy in identifying ‘good’ with natural properties
• an appeal to competent speakers’ intuitions about what questions remain substantive

Subsequent sections examine the argument’s origins, Moore’s own formulation, its logical structure, major criticisms, and the diverse ways in which both naturalist and non‑naturalist theories have attempted to accommodate or resist its implications for the nature of moral language and properties.

2. Origin and Attribution

The Open Question Argument is most closely associated with G. E. Moore and is introduced in his 1903 work Principia Ethica. Moore is generally credited with both naming and systematically deploying the argument, although historians note several intellectual precursors.

2.1 Attribution to Moore

In Principia Ethica chapter 1, Moore introduces the test for proposed definitions of ‘good’ and uses the phrase “open question” in order to highlight the non‑triviality of asking whether any candidate natural property is in fact good. Subsequent writers have labeled this pattern of reasoning the Open Question Argument, a term not used by Moore as a fixed technical label but derived from his repeated contrasts between open and closed questions.

Moore’s role can be summarized as follows:

2.2 Intellectual Precursors

Some historians identify affinities with earlier thinkers:

• David Hume is often cited for the “is–ought gap,” though his focus is on inference rather than definition.
• Henry Sidgwick raised worries about analyzing ‘ought’ and ‘good’ in purely psychological or hedonistic terms.
• Neo‑Kantian and idealist discussions of normativity also questioned reductions of value to natural properties.

However, these predecessors did not formulate the specific open question test as Moore did, nor did they coin the notion of a naturalistic fallacy.

2.3 Later Naming and Dissemination

The expression “Open Question Argument” gained currency in mid‑20th‑century analytic philosophy, as Moore’s work was incorporated into standard textbooks and metaethical debates. Figures such as C. D. Broad, W. D. Ross, and later A. J. Ayer and R. M. Hare helped to disseminate and interpret Moore’s challenge, sometimes adapting it to their own projects in intuitionism or non‑cognitivism.

3. Historical Context

The Open Question Argument emerges from a specific intellectual setting at the turn of the 20th century, marked by shifts within both ethics and analytic philosophy.

3.1 Late 19th‑Century Ethical Theories

Moore’s contemporaries advanced various naturalistic and psychological accounts of value:

Moore read these theories as attempting to define ‘good’ in terms of such properties, and he framed the OQA as a reaction against this tendency.

3.2 Early Analytic Philosophy

Moore’s work belongs to the first wave of analytic philosophy, alongside Bertrand Russell and others at Cambridge. The period emphasized:

• Conceptual analysis and attention to ordinary language
• Distinctions between simple and complex concepts
• Skepticism about metaphysical systems inherited from British Idealism

Within this environment, the Open Question Argument functions as a paradigmatic analytic tool, using linguistic phenomena to test proposed philosophical identifications.

3.3 Opposition to Idealism and Naturalism

Moore opposed both the idealism dominant in late 19th‑century Britain and the various naturalistic reductions in ethics. He held that:

• Moral properties are objective and not reducible either to mental constructs (idealism) or to natural/psychological facts (naturalism).
• The concept ‘good’ is simple and indefinable, analogous to basic color concepts.

The Open Question Argument is embedded in this broader program: it is one of Moore’s main tools for rejecting philosophical accounts that, in his view, conflate the normative with the descriptive.

3.4 Subsequent Reception Context

The argument’s later reception is shaped by:

• The rise of logical positivism and then linguistic philosophy, which reinterpreted metaethical questions in terms of meaning and use.
• The development of Fregean and later Kripkean semantics, which provided resources both to criticize and to reframe Moore’s reasoning.

This historical background informs how later sections interpret the argument’s structure, its ambition, and the objections it attracted.

4. Moore’s Formulation in Principia Ethica

In Principia Ethica, Moore develops the Open Question Argument within his broader examination of the concept ‘good’. His formulation combines three main elements: the indefinability of ‘good’, a test for proposed definitions, and the accusation of a naturalistic fallacy.

4.1 Indefinability of ‘Good’

Moore begins by claiming that ‘good’ is a simple and unanalyzable concept:

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

— G. E. Moore, Principia Ethica

He compares ‘good’ to color predicates like ‘yellow’: just as ‘yellow’ cannot be defined in more basic terms but can only be pointed out or grasped directly, so too with ‘good’. This claim of simplicity provides the backdrop against which he evaluates competing definitions.

4.2 The Open Question Test

Moore’s central maneuver is to propose a linguistic test. Suppose a philosopher offers:

• ‘Good’ = ‘pleasant’
• ‘Good’ = ‘what we desire to desire’
• ‘Good’ = ‘more evolved’

Moore notes that competent speakers can always intelligibly ask:

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“Is pleasure really good?”
“Is what we desire to desire always good?”

For Moore, the fact that such questions are not conceptually closed—unlike “Is a bachelor an unmarried man?”—shows that the terms are not analytically equivalent. The openness persists, he argues, even when we fully grasp both sides of the proposed definition.

4.3 Application to Naturalistic and Theological Accounts

Moore applies the same test not only to naturalistic but also to theological or metaphysical identifications, such as:

• ‘Good’ = ‘what God wills’
• ‘Good’ = ‘what is in accordance with reality’

He maintains that it remains an open question whether what God wills is good or whether accordance with reality is good, suggesting that none of these are definitions of ‘good’ in the strict sense.

4.4 Role within Principia Ethica

Within Principia Ethica, the Open Question Argument supports two key theses:

Moore’s later chapters build his intuitionist and axiological views on this foundation, but the specific argumentative pattern concerning open questions is developed primarily in his early discussion of meaning and analysis.

5. The Argument Stated

Although Moore does not present the Open Question Argument as a numbered proof, later commentators typically reconstruct it in a more formal way to clarify its commitments. A common schematic statement runs as follows.

5.1 Informal Statement

For any proposed definition of ‘good’ in terms of some property N (e.g., pleasure, desire‑satisfaction, evolutionary fitness):

1. If ‘good’ meant the same as N, then the question “Is N good?” would be closed or trivial, in the way that “Are all bachelors unmarried?” is trivial once we understand the language.
2. However, competent speakers can still meaningfully and substantively ask, “But is N really good?”
3. Therefore, ‘good’ does not mean the same as N and is not analytically equivalent to it.

Moore takes the repeated failure of candidate identifications to pass this test to support the thesis that ‘good’ is both indefinable and non‑natural.

5.2 Canonical Reconstruction

One influential reconstruction, closely aligned with the overview given in this entry, presents the argument as a reductio against ethical naturalism:

Moore supplements this with the further, more controversial, conclusion that goodness is a simple, non‑natural property known by intuition. Later sections distinguish the core Open Question Argument from these additional Moorean commitments.

5.3 Scope

Moore suggests that this pattern applies:

• across different kinds of candidate analyses (hedonistic, evolutionary, desire‑based, theological), and
• to moral predicates beyond ‘good’, though his primary focus remains on ‘good’ as the “most fundamental” ethical concept.

This reconstructed statement sets up the more detailed treatment of its logical form and the examination of its premises.

6. Logical Structure and Form

Commentators generally treat the Open Question Argument as having a distinctive logical structure aimed at analytic equivalence claims.

6.1 Reductio Structure

The argument is often characterized as a reductio ad absurdum against proposed definitions:

1. Assume: ‘Good’ is analytically equivalent to some property N (e.g., pleasure).
2. Derive: On this assumption, the identity statement “Whatever is N is good” should be trivial or knowable a priori for competent speakers.
3. Observe: In practice, competent speakers regard “Is N good?” as a substantive, open question.
4. Conclude: The assumption of analytic equivalence leads to a mismatch with linguistic competence data and should be rejected.

This structure aims to show that naturalistic or metaphysical definitions cannot satisfy the criteria for analyticity.

6.2 Use of a Linguistic Test

The argument relies heavily on a test involving ordinary language: the openness or closedness of certain questions for competent speakers. Formally, it moves from a condition on analytic equivalence:

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If A and B are analytically equivalent, then “Is A B?” is conceptually closed

to an empirical or intuitive claim about actual linguistic usage:

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“Is pleasure good?” is not conceptually closed.

The logical force of the argument depends on treating these judgments about intelligibility and triviality as reliable indicators of underlying semantic relations.

6.3 Target: Analytic, Not Metaphysical, Identity

In Moore’s own presentation, the primary target is analytic definitional identity—what later philosophers describe as sameness of meaning or sense. The structure concerns:

• equivalence of concepts or meanings (‘good’ vs. ‘pleasant’), not
• direct metaphysical identity of properties (goodness vs. pleasure) as such.

Later critics and defenders debate whether the argument can, or should, be extended from claims about meaning to claims about metaphysical reduction; but structurally, the original form is best read as semantic.

6.4 Patterned Generality

Moore presents the argument not as a one‑off refutation of a particular theory, but as a schema that can be instantiated for any candidate N. Its logical form is thus second‑order in a loose sense: it quantifies over possible analyses of ‘good’ and claims that each will fail the openness test.

This generality is crucial for Moore’s broader conclusion that no naturalistic or theological definition can succeed, rather than merely that some specific proposals are flawed.

7. Premises Examined

The Open Question Argument rests on several key premises. Later discussion often turns on evaluating these assumptions rather than the conclusion itself.

7.1 Premise about Analytic Equivalence and Closed Questions (P1)

The first premise states that if two expressions are analytically equivalent, the question linking them should be closed or trivial. For example:

• “Is a triangle a three‑sided figure?”
• “Is a bachelor an unmarried man?”

Proponents argue that once we understand the relevant concepts, such questions are resolved purely by conceptual competence, without empirical investigation. The premise thus connects analyticity with a specific phenomenology of triviality or uninterest.

Critics question whether this connection is always reliable. Some maintain that even analytic truths can seem informative or non‑obvious to many speakers, especially before theoretical reflection. Others suggest that ordinary linguistic intuitions may not perfectly track the technical notion of meaning-identity.

7.2 Premise about Openness of Moral Questions (P2)

Moore’s second premise claims that for any candidate N, “Is N good?” remains an open question for competent speakers. This is grounded in:

• introspective judgments about how such questions feel (substantive, not trivial), and
• the apparent disagreement among reflective agents about particular analyses.

Supporters note that even those who endorse naturalistic theories typically regard their claims as substantive philosophical theses, not as mere definitions by stipulation, which seems to presuppose openness.

Skeptics argue that this premise may:

• overgeneralize from pre‑theoretical usage,
• overlook the possibility that apparent openness reflects cognitive limitations or incomplete understanding, or
• conflate what is open to lay speakers with what is open to idealized, fully informed theorists.

7.3 Premise Linking Openness to Non‑Analyticity (P3)

The third premise infers from the persistence of open questions to the conclusion that no analytic equivalence holds. This inference hinges on treating competence intuitions as reliable evidence about meaning.

Some philosophers accept this connection as a standard methodological tool in conceptual analysis across philosophy. Others, influenced by later work in the philosophy of language, argue that:

• questions can remain cognitively significant even when expressions are co‑referential (invoking the sense–reference distinction), and
• analytic and a posteriori identities may both admit seemingly open questions.

7.4 Auxiliary Assumptions

The argument also presupposes, more implicitly:

• that ‘good’ is a suitable target for definition in the same sense as descriptive terms,
• that speakers share a sufficiently unified concept of goodness, and
• that ordinary language data are reliable guides for metaethical theory.

Each of these assumptions has been examined and sometimes contested in subsequent literature, shaping how philosophers assess the overall force of the Open Question Argument.

8. Targeting Ethical Naturalism and Other Reductions

The Open Question Argument is primarily deployed against ethical naturalism, but Moore applies the same pattern to other reductive accounts of value.

8.1 Ethical Naturalism as Target

Ethical naturalism holds, roughly, that moral properties are identical to or fully reducible to natural properties describable by science or ordinary empirical discourse. Examples include:

Moore’s openness test is meant to show that in each case, it remains a substantive question whether pleasure, desire‑satisfaction, survival, or welfare is genuinely good, suggesting that these cannot be definitions of ‘good’.

8.2 Psychological and Sociological Reductions

Moore also targets theories that reduce morality to psychological or sociological facts, such as:

• ‘Good’ = ‘what is approved by my society’
• ‘Good’ = ‘what I (or we) tend to desire or praise’

He argues that we can still meaningfully ask whether what society approves is good, or whether our actual desires are good, indicating that such sociological or psychological properties do not capture the meaning of ‘good’.

8.3 Theological and Metaphysical Reductions

Beyond naturalism, Moore applies the argument to theological voluntarism and certain metaphysical accounts:

• ‘Good’ = ‘what God wills’
• ‘Good’ = ‘what is in accordance with the Absolute’ or with reality in an idealist sense.

Again, Moore contends that the questions “Is what God wills good?” or “Is the Absolute’s nature good?” are not trivial identity statements but substantive ethical questions, suggesting that such views commit a similar reductive mistake.

8.4 Scope and Limitations

The common thread across these targets is the attempt to render the normative property of goodness fully explicable in terms of some descriptive or non‑ethical property. Moore’s strategy is to deny that any such property can provide an analytic definition of ‘good’. Later debates examine whether his argument undermines only definitional reduction or also more modest forms of explanatory or metaphysical reduction by naturalists and others.

9. The Naturalistic Fallacy and Its Role

Alongside the Open Question Argument, Moore introduces the notion of the naturalistic fallacy, a label that has played a distinctive, and often controversial, role in metaethics.

9.1 Moore’s Characterization

Moore uses “naturalistic fallacy” to describe what he sees as a common error: identifying or defining the normative property good in terms of some natural or otherwise purely descriptive property. Typical examples include:

• ‘Good’ = ‘pleasant’
• ‘Good’ = ‘more evolved’
• ‘Good’ = ‘what we desire to desire’

Moore insists that such identifications make a category mistake, confusing a genuinely normative property with a natural or factual property.

9.2 Relationship to the Open Question Argument

The naturalistic fallacy is conceptually distinct from, but closely linked to, the Open Question Argument:

Moore takes the repeated failure of proposed definitions under the open question test as evidence that they involve the naturalistic fallacy.

9.3 Normative vs. Descriptive Distinction

A central idea behind the naturalistic fallacy is a sharp distinction between:

• Descriptive properties: how things are (e.g., pleasant, desired, evolved, commanded), and
• Normative properties: how things ought to be or what is good, right, or valuable.

Moore holds that good belongs irreducibly to the latter category. Treating any descriptive property as identical in meaning to ‘good’ is, on his view, to obscure this fundamental difference.

9.4 Misinterpretations and Later Usage

The term “naturalistic fallacy” has sometimes been conflated with Hume’s is–ought problem or with a general prohibition on deriving normative conclusions from descriptive premises. Moore’s own usage is narrower: it concerns definitions of ‘good’ rather than inference patterns.

Later authors have adopted, modified, or rejected the label:

• Some non‑naturalists retain it to express a robust descriptive–normative gap.
• Many naturalists argue that the notion is misleading or question‑begging, preferring to treat moral properties as amenable to naturalistic analysis.
• Others distinguish between Moore’s intended sense and broader metaethical cautions about reduction.

Within Moore’s framework, however, the naturalistic fallacy functions as the conceptual mistake that the Open Question Argument is designed to expose.

10. Key Variations and Extensions

Although rooted in Moore’s original discussion, the Open Question Argument has been reformulated and extended in various ways, often to address concepts beyond ‘good’ or to adjust to developments in philosophy of language and metaethics.

10.1 Beyond ‘Good’: Other Moral Terms

Some philosophers have explored whether similar reasoning applies to:

• ‘Right’ or ‘morally required’, asking whether proposed identifications with, for example, maximizing utility or conforming to ideal rules leave an open question (“But is maximizing utility really right?”).
• ‘Ought’ or ‘reason’, testing definitions in terms of preferences, desires, or rational choice.

These extensions examine whether Moore’s argument is specific to axiological concepts or generalizable across normative vocabulary.

10.2 Application to Reasons and Rationality

Later theorists, especially in the debate about normative reasons, have developed OQA‑style arguments against naturalistic analyses of ‘a reason’ as:

• ‘what would promote desire satisfaction’,
• ‘what figures in ideal rational choice’, or
• ‘what advances well‑being’.

They argue that we can still ask, “But is what promotes desire satisfaction really a reason to act?”, suggesting that the concept of a reason is not captured by such analyses.

10.3 Non‑Naturalist and Hybrid Reformulations

Some non‑naturalists have refined Moore’s pattern to fit more sophisticated semantics and metaphysics:

• Emphasizing supervenience rather than simple non‑naturalness, while maintaining that moral concepts are not analytically reducible.
• Crafting “open question” tests tailored to theories that posit a posteriori or functional identifications of moral properties with natural ones.

Hybrid theorists sometimes use an OQA‑inspired move selectively, to argue that moral concepts have both descriptive and normative components, with the latter resisting full reduction.

10.4 Linguistic and Pragmatic Variants

With the rise of pragmatics and use‑based theories of meaning, some philosophers reinterpret the OQA pattern as a comment on:

• the role of moral terms in discourse (expressing endorsement, guiding action),
• the contrastive or evaluative force of ‘good’ that definitions in purely factual terms may fail to capture.

On this view, the openness of questions reflects differences in speech act type or pragmatic function, rather than strict semantic non‑equivalence.

10.5 Methodological Adaptations

Finally, the OQA structure has influenced broader philosophical methodology: similar “can we still intelligibly ask…?” tests are deployed in debates about:

• personal identity,
• mental states and brain states,
• free will and determinism.

These adaptations extend the style of Moore’s argument—using judgments of openness and triviality—beyond ethics, even when the substantive conclusions diverge from Moore’s own non‑naturalism.

11. Standard Objections and Critiques

The Open Question Argument has attracted a wide range of criticisms. Many focus on its assumptions about language and its inference from semantic to metaphysical claims.

11.1 Sense–Reference and Frege–Geach‑Style Objections

One influential line of critique draws on Frege’s distinction between sense and reference:

• Two expressions can refer to the same property while having different cognitive significance (e.g., ‘Hesperus’ and ‘Phosphorus’).
• Statements like “Hesperus is Phosphorus” are informative and non‑trivial despite expressing an identity.

Critics argue that the openness of “Is pleasure good?” could similarly reflect differences in mode of presentation rather than non‑identity of the underlying property. Thus, the persistence of open questions would not, by itself, refute reductive identifications.

11.2 Parity with Scientific Identifications

Another objection highlights the apparent parity between the OQA and reactions to scientific discoveries:

• Prior to learning chemistry, one might intelligibly ask, “Water is H2O, but is H2O really water?”
• Before thermal physics, “Heat is molecular motion, but is molecular motion really heat?” might seem open.

If such questions can be both open and compatible with true identity statements, critics contend, then the openness of moral questions does not show the impossibility of moral–natural property identities.

11.3 Semantic vs. Metaphysical Conflation

Many objections stress a distinction between:

• semantic non‑equivalence (differences in meaning), and
• metaphysical identity (sameness of property or fact).

Even if the OQA establishes that ‘good’ is not analytically equivalent to any natural term, it may not rule out a posteriori identifications on the model of scientific reductions. Naturalists often argue that Moore conflates these two levels.

11.4 Competence and Conceptual Role Objections

Some philosophers challenge Moore’s reliance on competence intuitions:

• Ordinary speakers may not fully grasp the theoretical nature of moral concepts.
• Intuitions of openness might reflect conceptual incompleteness, ambiguity, or the complexity of ethical reflection rather than sharp semantic boundaries.

On this view, the OQA overestimates what follows from how questions seem to non‑specialists.

11.5 Objections to the Naturalistic Fallacy Charge

Critics also question Moore’s labeling of naturalistic analyses as committing a fallacy:

• Some see it as question‑begging, assuming from the outset that normative properties cannot be natural.
• Others argue that it misdescribes naturalist projects, which may aim at theoretical identifications or explanations, not simple definitional substitutions.

These critiques collectively challenge both the soundness of the OQA’s premises and the strength of its conclusions against naturalism and other reductions.

12. Responses from Non-naturalists

Philosophers sympathetic to non‑naturalist moral realism often embrace the spirit, though not always the exact letter, of Moore’s Open Question Argument, while refining it in light of subsequent objections.

12.1 Endorsement and Refinement of the Core Insight

Many non‑naturalists accept that:

• There is a robust distinction between descriptive and normative properties.
• Attempts to define ‘good’ purely in natural terms overlook something essential about its normative role.

They often use the OQA as confirmatory evidence rather than as a standalone proof, integrating it with broader arguments about normative authority, reasons, or value.

12.2 Adjusting to Sense–Reference Critiques

Acknowledging Fregean and Kripkean developments, some non‑naturalists concede that:

• The OQA may not strictly rule out a posteriori naturalistic identities.

However, they contend that:

• The persistent openness of moral questions, even under ideal reflection, suggests that moral properties are not best understood as identical to any natural properties.
• The normative “oomph” or reason‑giving force of moral predicates cannot be captured by naturalistic descriptions alone.

In this way, they reinterpret the OQA as pointing to a deeper explanatory gap rather than a straightforward semantic impossibility.

12.3 Supervenience and Non-Reductive Structure

Contemporary non‑naturalists often combine OQA‑style considerations with the thesis that:

• Moral properties supervene on natural properties (no moral difference without some natural difference),
• yet remain distinct and irreducible.

The OQA is then taken to show that supervenience does not amount to reduction, and that moral concepts play a unique role in practical reasoning and deliberation.

12.4 Epistemic and Methodological Support

Non‑naturalists sometimes argue that:

• Our knowledge of moral truths via intuition, reflection, or rational insight fits better with the idea that moral properties are sui generis.
• The OQA highlights that moral inquiry is not simply an extension of empirical science, even if it is informed by empirical facts.

Here, the argument bolsters an overall picture in which moral facts are objective yet non‑natural, and moral terms resist purely descriptive analysis.

12.5 Distinguishing Moore’s Version from Later Non-naturalism

Some non‑naturalists distance themselves from specific Moorean claims (e.g., that ‘good’ is absolutely indefinable or simple), while retaining a modified OQA. They may allow for partial analyses or functional characterizations of moral concepts, insisting only that no such analysis eliminates the need for an irreducible normative component. In this more moderate form, the OQA serves as a constraint on acceptable theories rather than a decisive refutation of all naturalism.

13. Responses from Naturalists and Reductionists

Naturalists and reductionists typically reject Moore’s non‑naturalist conclusion while offering different strategies for accommodating or resisting the Open Question Argument.

13.1 Analytic Naturalism and Conceptual Analysis

Some analytic naturalists accept Moore’s focus on meaning but argue that:

• Adequate conceptual analysis may reveal that moral terms are complex descriptive concepts, possibly involving idealized preferences, social practices, or well‑being.
• The apparent openness of questions like “Is pleasure good?” may dissipate under a more careful reconstruction of our ordinary concept of good.

On this approach, the OQA is viewed as highlighting the difficulty of moral analysis, not its impossibility.

13.2 A Posteriori Naturalism

Other naturalists embrace scientific analogies and emphasize a posteriori identities:

• Even if ‘good’ is not analytically equivalent to any natural term, the property goodness might still be identical to some natural property discovered empirically or through theoretical reflection.
• The OQA is then interpreted as mistaking the epistemic status of moral identities (empirical, substantive) for evidence against their metaphysical possibility.

Philosophers such as Peter Railton, David Brink, and Frank Jackson develop accounts in which moral properties are realized by, or identical to, patterns of natural facts that best explain our considered moral judgments.

13.3 Response to Parity and Sense–Reference Objections

Naturalists often deploy the parity with scientific identifications and sense–reference critiques:

• They argue that the ongoing intelligibility of “Is pleasure really good?” is analogous to the historical intelligibility of “Is water really H2O?”.
• Hence, openness does not show non‑identity; it shows that the identification (if true) is informative and discovered through inquiry.

On this view, the OQA reveals only that moral reductions would be substantive philosophical theses, not truisms.

13.4 Revisionary and Error Theoretic Responses

Some reductionists adopt a more revisionary stance:

• They may concede that ordinary use of ‘good’ does not perfectly align with any neat naturalistic property.
• Nevertheless, they advocate reforming moral language to better fit a naturalistic conception, or they endorse error theory, claiming that most ordinary moral discourse is systematically false while still allowing a naturalistic core.

In such frameworks, the OQA is treated as a datum about ordinary usage that does not constrain the best theoretical vocabulary.

13.5 Non-Reductive and Supervenience-Based Naturalisms

Finally, some naturalists respond by weakening the reductive ambition:

• They accept that ‘good’ may not be definitionally reducible, yet maintain that moral properties supervene on, and are fully grounded in, natural properties.
• The OQA is interpreted as a challenge to simple analytic reductions, not to broader naturalistic explanations of morality.

In these accounts, the argument is partially accommodated but seen as compatible with a robust, if non‑reductive, moral naturalism.

14. Expressivist and Non-Cognitivist Reinterpretations

Expressivist and other non‑cognitivist theories of moral language reinterpret the Open Question Argument, often repurposing its insights for their own agendas.

14.1 Rejection of Descriptive Starting Point

Non‑cognitivists such as A. J. Ayer and R. M. Hare maintain that:

• Moral sentences primarily express attitudes, emotions, or prescriptive stances, rather than describe moral facts.
• ‘Good’ does not function like a descriptive predicate; instead, it plays an evaluative or guiding role.

From this perspective, Moore’s assumption that ‘good’ names a property (natural or non‑natural) is questioned. The OQA is then seen as evidence that moral language is not purely descriptive.

14.2 Openness as Expression of Attitudinal Space

Expressivists interpret the openness of questions like “Is pleasure really good?” differently:

• The question remains open because it invites reconsideration of our attitudes toward pleasure, not because it tests an underlying property identity.
• The persistence of open moral questions is taken to show that ethical discourse involves practical deliberation and attitude revision, rather than the mere application of fixed definitions.

On this view, OQA‑style phenomena support the expressive, rather than descriptive, character of moral language.

14.3 Hare’s Prescriptivism

Hare develops a specifically prescriptivist reading:

• Moral terms like ‘good’ and ‘ought’ are understood as universalizable prescriptions.
• The failure of naturalistic definitions reflects the fact that moral words carry logical features (like universalizability) that are not captured by purely descriptive predicates.

Hare preserves Moore’s observation that moral concepts are not exhausted by natural descriptions, while rejecting Moore’s non‑naturalist metaphysics.

14.4 Quasi-Realist and Hybrid Expressivist Treatments

Later quasi‑realists and hybrid expressivists (e.g., Simon Blackburn, Allan Gibbard) retain an expressivist core but acknowledge that moral discourse resembles factual discourse in many ways. They often treat the OQA as:

• highlighting the special pragmatic role of moral terms, and
• indicating that even if moral language can be “projected” into a realist‑sounding framework, its foundations lie in attitudes and plans.

The openness of moral questions is then understood as tracking the contingent stability of our evaluative practices, not an ontological gap.

14.5 Limits of the Reinterpretation

While expressivists frequently invoke OQA‑style data, they typically do not endorse Moore’s own conclusion that there exists a simple non‑natural property of goodness. Instead, they transform the argument into a diagnostic tool:

• rather than showing what moral properties are, it shows that looking for such properties may be the wrong model for understanding moral language.

This reinterpretation provides an alternative way of accommodating Moore’s linguistic observations within a broadly anti‑realist or non‑descriptivist framework.

15. Impact on Contemporary Metaethics

The Open Question Argument has had a lasting and multifaceted impact on contemporary metaethical theory, shaping debates about reduction, meaning, and normativity.

15.1 Structuring the Naturalism Debate

OQA considerations continue to structure the central divide between:

As a result, many metaethical views are, at least partly, defined by their stance toward Moore’s argument.

15.2 Methodological Influence

The argument helped entrench the use of conceptual analysis and competence intuitions as data in metaethics. Even critics of Moore often employ similar techniques, asking:

• whether a proposed analysis leaves open or closed certain questions for competent speakers,
• whether it respects the inferential role and practical function of moral concepts.

This methodology remains central, though increasingly supplemented by experimental philosophy, linguistics, and cognitive science.

15.3 Development of Sophisticated Naturalisms

In response to OQA‑style worries, naturalists have developed more nuanced theories:

• A posteriori, Cornell‑style moral realist accounts that emphasize causal and explanatory roles of moral properties.
• Functional and dispositional analyses of moral terms that move beyond simple definitional reductions.

These theories often explicitly address Moore’s challenge, attempting to explain how moral concepts can be analytically distinct yet metaphysically grounded in the natural.

15.4 Renewed Focus on Normativity and Reasons

Contemporary discussions of normative reasons, ought, and rationality frequently employ OQA‑like tests, arguing that:

• analyses in terms of desires, preferences, or instrumental rationality leave a residual open question about genuine normative authority.

In this way, Moore’s pattern has been generalized to a broad range of normative notions beyond ‘good’.

15.5 Interaction with Philosophy of Language and Metaphysics

Work on:

• the sense–reference distinction,
• two‑dimensional semantics, and
• metaphysical grounding

has been applied to refine or challenge the OQA. These developments have made the debate more intricate, involving questions about conceptual role, reference‑fixing, and the distinction between semantic and metaphysical reductions.

Overall, the Open Question Argument continues to function less as a universally accepted proof and more as a central problem that any comprehensive metaethical theory must address.

16. Legacy and Historical Significance

The historical significance of the Open Question Argument extends beyond its original context in Moore’s Principia Ethica, influencing both the trajectory of metaethics and broader philosophical practice.

16.1 Foundational Role in Analytic Metaethics

The OQA is often cited as a founding moment of analytic metaethics:

• It shifted focus from substantive questions about which things are good to questions about the nature of moral concepts and properties.
• It set an agenda framed around the descriptive–normative distinction, reduction, and the status of ethical naturalism.

Subsequent metaethical theories—non‑naturalist, naturalist, and expressivist alike—have been shaped in conversation with Moore’s challenge.

16.2 Contribution to Analytic Philosophy’s Self-Understanding

Within analytic philosophy more broadly, the OQA exemplified:

• the use of linguistic and conceptual analysis as a primary philosophical method,
• the idea that careful attention to ordinary questions could undermine grand metaphysical systems.

It thus contributed to the self‑conception of analytic philosophy as precise, language‑focused, and suspicious of category mistakes.

16.3 Influence on Adjacent Debates

The argumentative style pioneered by Moore influenced discussions in:

While the substantive issues differ, the “open question” motif recurs as a way of challenging proposed reductions.

16.4 Reassessment in Light of Later Semantics

Developments in semantics and metaphysics have led many to regard Moore’s original formulation as naïve or incomplete, particularly regarding:

• the possibility of a posteriori identities, and
• distinctions between meaning and reference.

Nevertheless, even critics often acknowledge the OQA’s historical importance in forcing a refinement of these concepts and in clarifying what is at stake in moral reductionism.

16.5 Enduring Educational and Canonical Status

The Open Question Argument remains a staple of:

• introductory courses in ethics and metaethics,
• anthologies and encyclopedias on moral philosophy,
• discussions of philosophical method and the history of analytic thought.

Its endurance reflects not only the strength or weakness of its conclusions, but also its role as a pedagogically vivid illustration of how subtle questions about meaning can bear on larger issues about value, objectivity, and the scope of scientific explanation.