Conventionalism

1. Introduction

Conventionalism is a family of views holding that many principles we treat as fundamental—especially in logic, mathematics, geometry, science, ethics, and politics—depend, in important ways, on human conventions: agreements, practices, or choices. Rather than seeing these principles as straightforwardly discovered features of a mind‑independent order, conventionalists emphasize the roles of stipulation, coordination rules, and linguistic or institutional frameworks.

Classical forms of conventionalism emerged in late 19th‑ and early 20th‑century debates about non‑Euclidean geometry, the axiomatization of mathematics, and the structure of scientific theories. Figures such as Henri Poincaré and Pierre Duhem argued that some central components of scientific and mathematical frameworks are selected because they are convenient, simple, or unifying, rather than uniquely fixed by empirical data.

Conventionalists do not usually deny the existence of an external world or of empirical constraints on theory; instead, they contend that:

• Different, equally adequate frameworks can fit the same observational facts.
• Some statements that seem necessary or a priori may instead codify rules of representation or linguistic choices.
• Disputes in metaphysics, ethics, or political theory sometimes turn on verbal or framework differences more than on deep disagreements about reality.

Opponents argue that conventionalism risks collapsing into relativism, instrumentalism, or triviality if any principle can be “saved” by adjusting conventions. Supporters reply that identifying the conventional element in our theories clarifies where rational choice, pragmatic criteria, and social practices enter into domains often treated as purely objective.

This entry surveys the historical development of conventionalism, its core theses and internal variants, its application to different philosophical areas, and the main criticisms and transformations it has undergone, from early geometric and logical forms to contemporary neo‑conventionalist approaches.

2. Historical Origins and Founding Figures

Although explicit “conventionalism” is a late 19th‑century development, many of its themes have earlier precedents. Ancient Greek contrasts between nomos (law, custom) and physis (nature), and sophistic emphases on the human origin of norms, anticipate later distinctions between conventional and natural orders. Early modern thinkers like David Hume and Immanuel Kant also influenced later conventionalism by stressing the role of human practices and conceptual schemes.

The specifically modern school, however, is usually traced to French and Central European contexts between about 1880 and 1910. The discovery of non‑Euclidean geometries, new formalisms in mechanics and electrodynamics, and attempts to axiomatize mathematics prompted questions about how theory, mathematics, and experience are related.

2.1 Henri Poincaré

Henri Poincaré (1854–1912) is commonly regarded as the founding figure of philosophical conventionalism. In works such as La science et l’hypothèse (1902), he argued that the choice of geometrical structure for physical space, and of certain principles in mechanics and physics, involves conventions guided by simplicity and convenience. Geometry, in his view, does not describe space uniquely; it forms part of a coordinated system of measurement rules and theoretical postulates.

"

"One geometry cannot be more true than another; it can only be more convenient."

— Henri Poincaré, La science et l’hypothèse

2.2 Pierre Duhem

Pierre Duhem (1861–1916) developed a related but distinct approach in the philosophy of science. In La théorie physique (1906), he defended a holistic view of testing, where theories face experience as a whole. Because hypotheses are intertwined with auxiliary assumptions and measurement conventions, negative experimental results underdetermine which part of the theoretical network must be revised. This underdetermination fostered a Duhemian form of conventionalism about elements of theory choice.

2.3 Early Analytic and Logical Empiricist Developments

In the early 20th century, conventionalist ideas influenced Bertrand Russell, Ludwig Wittgenstein, and especially the Vienna Circle, where thinkers like Rudolf Carnap and Hans Reichenbach developed logical and linguistic versions of conventionalism. They reconceived logical truths, mathematical axioms, and coordination rules as grounded in linguistic frameworks and relativized a priori principles rather than in an independent metaphysical realm.

These founding figures established conventionalism as a distinctive response to both classical rationalism and straightforward empiricism, emphasizing the constructive role of human choices in structuring knowledge.

3. Etymology of the Name "Conventionalism"

The term “Conventionalism” derives from the Latin conventiō (genitive conventiōnis) meaning “agreement,” “coming together,” or “contract.” Through Old and Middle French convention, it came to denote a formal agreement, contract, or assembly. The abstract noun conventionalisme in French was used in the 19th century to describe philosophical views that treat certain principles or classifications as resting on such agreements.

The English “convention” acquired a dual sense relevant to the doctrine:

1. Agreement or stipulation: explicit adoption of rules (e.g., treaty, standard of measurement).
2. Custom or established practice: implicit norms emerging from social use (e.g., etiquette, linguistic habits).

“Conventionalism” thus came to name positions that ground specific kinds of necessity, normativity, or structure in either explicit stipulation or entrenched practice, rather than in nature or pure reason alone.

3.1 Conceptual Implications of the Etymology

The etymology underscores central contrasts:

Conventionalists typically exploit these contrasts to argue that:

• Some “laws” (logical, mathematical, or social) are closer to nomos than to physis.
• Certain a priori-seeming principles may instead be posited in the course of structuring inquiry.

At the same time, not all uses of “conventional” are embraced. Critics sometimes use it pejoratively to mean “arbitrary,” “merely verbal,” or “unserious,” whereas many conventionalists insist that conventions can be highly constrained, rationally assessable, and indispensable for scientific and social coordination. The name “Conventionalism” therefore encodes both the central thesis and some of the controversies surrounding it.

4. Intellectual and Scientific Context

Conventionalism arose within a dense network of intellectual developments at the turn of the 20th century, particularly in France, Germany, and Austria. Several scientific and philosophical shifts made the idea of convention‑dependent principles salient.

4.1 Non‑Euclidean Geometry and Space

The discovery of non‑Euclidean geometries by Gauss, Lobachevsky, and Bolyai in the 19th century undermined the assumption that Euclidean geometry uniquely describes physical space. Philosophers and mathematicians confronted the question: if multiple internally consistent geometries exist, what fixes which one applies to the world? Conventionalists such as Poincaré argued that this choice relies partly on measurement conventions and coordinating principles, not just on direct observation.

4.2 Axiomatization of Mathematics and Logic

Efforts to systematize mathematics (Hilbert’s formalism, set theory) and logic (Frege, Russell) highlighted the role of axioms as stipulative starting points. Formal systems can be varied by altering axioms and rules of inference while retaining internal coherence. This raised the possibility that mathematical truth is, at least in part, a function of adopted rules rather than of a unique abstract reality.

4.3 Physics, Measurement, and Underdetermination

Late 19th‑century physics featured competing pictures of mechanics, optics, and electrodynamics, including debates over the ether, absolute space, and the nature of simultaneity. Measurement practices depended on standards (e.g., meter bars, clock synchronizations) that appeared partly conventional. Duhem’s work on the holistic testing of physical theories and Reichenbach’s later analysis of coordination principles reflected concerns about the underdetermination of theory by data.

4.4 Epistemology and the A Priori

Kantian philosophy had located geometry and certain physical principles in the synthetic a priori, necessary for the possibility of experience. The breakdown of Euclidean certainty and evolving scientific theories motivated attempts to reinterpret the a priori. Conventionalists proposed that such principles function as framework rules or relativized a priori elements, changeable with scientific revolutions yet still prior to, and partly constitutive of, empirical testing.

4.5 Linguistic and Social Developments

Growing interest in language, symbolism, and social science also supported conventionalist themes. Early sociology and anthropology studied customs and institutions as human constructions. Developments in linguistics emphasized arbitrary sign–meaning relations within language systems. These trends provided analogies for conceiving logical, mathematical, and scientific structures as products of collective agreement and use rather than as mirror images of an antecedently structured reality.

5. Core Doctrines and Central Maxims

While there is no single canonical formulation, several recurring theses characterize conventionalist positions across domains.

5.1 Framework‑Dependence of Truth and Necessity

Conventionalists typically hold that many truths—especially in logic, mathematics, and geometry—are true relative to a framework of definitions, rules, and coordination principles. Within a chosen system, these truths may appear necessary or a priori, but their necessity derives from adopted conventions rather than from access to a realm of abstract entities or metaphysical essences.

A common maxim is that “necessity is internal to language or framework”: to deny a logical law or geometrical axiom is to propose using a different system, not necessarily to assert a false empirical claim.

5.2 Underdetermination and Multiple Equivalent Descriptions

Another core doctrine is that empirical facts often underdetermine the choice of theoretical description. For any given body of data, several theories or formalisms may be empirically equivalent but conceptually distinct. Conventionalists maintain that choices among such alternatives are guided by simplicity, coherence, calculational tractability, and explanatory power, rather than by unique empirical mandates.

5.3 Conventions as Coordination Devices

Conventions are seen as practical tools enabling coordination—among observers, between theory and measurement, and within linguistic communities. Measurement standards, units, and synchronization procedures are paradigmatic. Conventionalists often stress that such conventions are not arbitrary: they are constrained by the goals of inquiry and by empirical feasibility, even if they are not forced upon us by nature.

5.4 Relativity and Revisability of the A Priori

A further maxim is that some principles function as a priori within a framework but are revisable in light of scientific change. Their role is to organize experience and make empirical testing possible. When empirical developments strain a framework, these principles can be altered or replaced, leading to a new set of conventions.

5.5 Verbal Disputes and Deflationary Metaphysics

Many conventionalists regard some philosophical disagreements as verbal or framework disputes: parties talk past one another because they employ different conceptual schemes. Adjusting definitions or translating between frameworks can dissolve apparent controversies. This attitude often accompanies a deflationary or structuralist metaphysics that downplays deep ontological commitments in favor of attention to representational practice.

These maxims are interpreted and weighted differently by various conventionalists, giving rise to multiple internal strands of the doctrine.

6. Metaphysical Views and Ontological Commitments

Conventionalism is more a family of metaphysical attitudes than a single doctrine. Its central metaphysical move is to deflate or relocate certain kinds of structure—from the fabric of reality into the structure of our frameworks, languages, or practices.

6.1 Anti‑Realism about Certain Structures

Many conventionalists are anti‑realist or at least agnostic about the independent existence of:

• Geometric properties of physical space (e.g., exact curvature).
• Abstract mathematical entities (numbers, sets).
• Logical forms as mind‑independent relations.

On this view, such structures are not “out there” awaiting discovery; they are artifacts of our representational systems. Nonetheless, conventionalists typically accept a minimal realism about observable phenomena and causal interactions, which impose constraints on which conventional frameworks are viable.

6.2 Structuralism and Thin Objects

Conventionalist metaphysics is often structuralist: what matters is the relational role objects play within a system, not their intrinsic nature. Mathematical or theoretical “objects” are sometimes treated as “thin posits”—entities whose identity is fully specified by the axioms and rules of a theory. This stance can coexist with different technical ontologies (e.g., set‑theoretic, algebraic) as long as these are understood as interchangeable representational devices.

6.3 Framework‑Relative Ontology

Logical positivist and neo‑Carnapian strands embrace a framework‑relative ontology. According to this view:

• Questions like “Do numbers exist?” are meaningful only within a linguistic framework that introduces number‑talk.
• Adopting a framework is a pragmatic choice, not a factual claim about what there really is.
• Once a framework is adopted, internal existence claims (e.g., “There is a prime greater than 100”) are straightforwardly true or false by the rules of the framework.

6.4 Conventionalism and Metaphysical Disputes

Conventionalists often regard certain metaphysical debates—about, for example, the reality of spacetime points, possible worlds, or essences—as disputes over language or conceptual scheme rather than over an independent realm. Critics see this as either dissolving substantive metaphysics or reducing it to conceptual engineering. Proponents argue that clarifying the conventional components of ontological commitment helps distinguish genuine empirical disagreements from terminological choices.

6.5 Limits of Conventionalist Metaphysics

There is disagreement about how far conventionalist metaphysics should extend. Some advocate moderate conventionalism, restricting it to formal or theoretical structures, while others see broader implications for kinds, properties, and even persons. The extent to which conventionalism can be applied without collapsing into global relativism remains a central issue in evaluating its metaphysical scope.

7. Epistemological Views and the Status of A Priori Knowledge

Conventionalism offers a distinctive account of a priori knowledge and the relation between meaning, rules, and experience.

7.1 A Priori as Knowledge of Conventions

Conventionalists typically reinterpret many a priori truths as expressing rules of language or framework stipulations rather than as reporting independent facts. Knowing that “no object can be both completely red and completely green all over at the same time” may, on this view, amount to understanding how we use color predicates and what counts as a correct application within our system.

Similarly, the laws of logic and basic principles of arithmetic can be seen as implicit definitions or constitutive rules: by adopting them, we fix the meanings of connectives and numerals. A priori knowledge is then, in large part, knowledge of our own conventions.

7.2 Coordination Principles and the Relativized A Priori

In philosophy of science, conventionalists highlight coordination principles—rules linking theoretical terms to observation (e.g., defining simultaneity via light signals). These principles often appear necessary for the empirical application of a theory and are thus treated as a priori within a framework. Reichenbach and others describe them as relativized a priori: they are not derived from experience, but they can be revised when a new theory demands different coordination.

7.3 Justification of Conventions

Epistemologically, the choice of conventions is not viewed as arbitrary. Criteria commonly cited include:

• Internal consistency of the resulting system.
• Simplicity and elegance of formulation.
• Empirical fruitfulness, including predictive success and unification.
• Pragmatic utility, such as ease of calculation or communication.

Proponents suggest that such criteria guide rational choice among alternative frameworks when evidence underdetermines theory.

7.4 Analytic–Synthetic Distinction

Many conventionalists defend some version of the analytic–synthetic distinction, interpreting analytic truths as those fixed by convention (meaning or definition) and synthetic truths as those depending on empirical facts. Later critics, especially Quine, challenge the sharpness of this distinction. Some neo‑conventionalists respond by adopting a gradient view: the analytic/synthetic divide is not absolute but still useful for modeling how much of a statement’s content is convention‑dependent.

7.5 Limits and Critiques

Critics argue that reducing the a priori to conventions either trivializes it (making it mere wordplay) or obscures how conventions themselves can be known or justified. Conventionalists reply that uncovering the rule‑governed character of many a priori judgments clarifies their special status without positing mysterious cognitive faculties, and that reflection on practice, implicit norms, and inferential roles provides a non‑mystical basis for a priori insight.

8. Conventionalism in Geometry, Logic, and Mathematics

Conventionalism has been especially influential in debates over the foundations of geometry, logic, and mathematics, where questions of necessity and structure arise most sharply.

8.1 Geometric Conventionalism

Poincaré’s geometric conventionalism holds that the geometry used to describe physical space is not uniquely determined by experience. Different geometries (Euclidean, hyperbolic, elliptic) can fit the same observational data when combined with appropriate measurement conventions and physical hypotheses (e.g., about how rods and clocks behave).

According to this view:

• Geometry is part of a conventionally chosen framework linking theoretical structure to measurement.
• Empirical tests evaluate the whole package (geometry plus physical laws), not geometry in isolation.
• Choosing one geometry over another reflects considerations of simplicity and overall convenience.

Relativistic physics complicated this picture: some argue that general relativity vindicates a non‑conventional, dynamically determined geometry, while others maintain that a conventionalist reading remains viable by redistributing curvature between geometry and matter fields.

8.2 Logical Conventionalism

Logical conventionalism treats the laws of logic as adopted rules of inference rather than as descriptions of necessary features of reality. On this approach:

• Statements like “from A and A→B infer B” (modus ponens) express inferential licenses constituting the meanings of logical constants.
• Different logics (classical, intuitionistic, paraconsistent) can be viewed as alternative, coherent rule systems that communities may adopt for different purposes.

Carnap and others suggested that the choice of logic can be seen as a matter of linguistic framework choice, guided by pragmatic criteria. Critics question whether all logical laws can be made conventional without circularity, since conventions themselves seem to presuppose logic.

8.3 Mathematical Conventionalism

In mathematics, conventionalism ranges from moderate to radical forms:

• Moderate forms emphasize that axioms in areas like geometry, arithmetic, or set theory can be treated as implicit definitions; once adopted, they fix the subject matter and determine mathematical truths.
• Stronger forms approach a view of mathematics as a creation of formal systems, where consistency and usefulness replace reference to independently existing mathematical objects.

Hilbert’s formalism shares affinities with mathematical conventionalism, though not all formalists are conventionalists in the philosophical sense. Conventionalists contrast their stance with Platonism, which posits a realm of abstract entities, and with logicism, which attempts to reduce mathematics to purely logical truths.

Debates continue over whether conventionalism can adequately explain the applicability of mathematics in science and whether it can account for the apparent objectivity and intersubjective stability of mathematical practice without resorting to realism.

9. Conventionalism in Philosophy of Science

In philosophy of science, conventionalism focuses on how theoretical structures, laws, and coordination rules relate to empirical data and experimental practice.

9.1 Theory–Observation Holism and Underdetermination

Duhem’s work is central here. He argued that:

• Scientific hypotheses are not tested individually but as part of a network including auxiliary assumptions and background theories.
• A failed prediction thus does not specify which component is at fault; different revisions of the network are possible.
• Therefore, empirical data may underdetermine which theoretical system is correct.

Conventionalists interpret this to mean that some elements of scientific theories—often including basic principles or coordination rules—are maintained or revised according to conventional choices guided by non‑empirical criteria.

9.2 Coordination Principles and Measurement Conventions

Philosophy of science conventionalists emphasize the role of coordination principles linking theoretical entities (e.g., mass, charge, spacetime intervals) to measurement procedures. Many such principles are treated as conventional:

• Fixing units and standards (meter, second, kilogram).
• Defining simultaneity (e.g., via light signals in relativity).
• Specifying what counts as an ideal measurement device.

These conventions are necessary to apply theories to the world but are not themselves straightforwardly empirical hypotheses. They can, however, be revised if they cease to provide a coherent or fruitful connection between theory and observation.

9.3 Criteria for Theory Choice

Conventionalists in science stress that, when empirical ties are loose, theory choice relies on:

These criteria explain why scientists may retain or adopt certain frameworks even when rivals are empirically equivalent.

9.4 Instrumentalism and Realism

Conventionalism is often linked with instrumentalism, the view that theories serve as tools for prediction and systematization rather than as literal descriptions of unobservables. Some conventionalists adopt this stance explicitly; others hold that while some aspects of theories are conventional, there may still be a realist core about causal structures or entities.

Scientific realists argue that conventionalism underestimates the explanatory success and convergent structure of mature theories. Conventionalists counter that acknowledging the conventional element clarifies how science can be both empirically constrained and conceptually plastic.

10. Ethical and Political Conventionalism

In ethics and politics, conventionalism concerns the source and status of norms, rights, and institutions. While the main historical development of conventionalism lies in epistemology and science, analogous ideas appear in meta‑ethics and political philosophy.

10.1 Ethical Conventionalism

Ethical conventionalism (or moral conventionalism) holds that moral norms and values are grounded in social agreements, practices, or customs, rather than in stance‑independent moral facts. On this view:

• What counts as right or wrong is determined by institutional rules, cultural traditions, or collective understandings.
• Moral disagreement often reflects clashing conventions rather than disagreements about objective values.

Some versions are descriptive, highlighting variation in norms across cultures. Others are normative or meta‑ethical, claiming that moral obligations exist because, and only because, a community has adopted certain rules.

Proponents argue that this explains the context‑dependence and historical variability of moral codes. Critics maintain that it threatens the possibility of robust moral criticism, especially of entrenched but unjust practices.

10.2 Political and Legal Conventionalism

In political philosophy, conventionalist themes appear in:

• Contractarian theories, which ground political authority and obligation in actual or hypothetical agreements among citizens.
• Legal positivism, which understands law as a system of socially recognized rules rather than as derivable from natural law or morality.

On such views, rights, duties, and institutional roles are not given by nature but are constructed through explicit legislation, judicial precedent, or informal practices.

Conventionalist accounts can support different political orientations:

10.3 Constraints on Ethical and Political Conventions

Even strong conventionalists often acknowledge constraints on what conventions are viable: human psychology, needs for cooperation, and basic facts about suffering or flourishing. These constraints are sometimes treated as naturalistic anchors that limit admissible moral or political arrangements, while leaving their detailed content to convention.

Debates continue over whether such anchoring suffices to avoid relativism, and how conventionalist accounts interact with theories of human rights, justice, and democratic legitimacy.

11. Internal Debates and Variants of Conventionalism

Conventionalism is internally diverse. Disagreements concern its scope, the strength of its claims, and its interpretation of key notions like convention, framework, and the a priori.

11.1 Moderate vs. Radical Conventionalism

A first divide separates moderate from radical versions:

• Moderate conventionalists restrict conventionalism to specific domains (e.g., geometry, some measurement principles, parts of mathematics). They often combine this with realism about empirical facts or causal structures.
• Radical conventionalists extend it broadly, suggesting that logical laws, mathematical objects, and even some metaphysical categories are products of our conceptual decisions or linguistic frameworks.

Critics of radical forms worry about global relativism; radicals sometimes respond by emphasizing intra‑framework objectivity and pragmatic constraints.

11.2 Explicit vs. Implicit Conventions

Another internal debate concerns whether conventions must be explicitly adopted or can be implicit in practice:

• Some stress explicit stipulation—for example, fixing units of measurement by international agreement.
• Others emphasize implicit rules, such as those governing everyday language or entrenched inferential practices, which may be followed without being consciously formulated.

This distinction affects how conventionalists understand a priori knowledge (as knowledge of explicit rules or of tacit norms) and how they view the possibility of revising conventions.

11.3 Linguistic, Logical, and Pragmatic Variants

Different strands highlight different aspects:

These variants differ in how directly they tie conventions to language, practice, or abstract structure.

11.4 Conventionalism and the Analytic–Synthetic Distinction

Within conventionalism, there are divergent attitudes toward the analytic–synthetic distinction:

• Some defend a robust distinction, treating analyticity as convention‑governed truth.
• Others, influenced by Quine, accept that the boundary is blurred but maintain that a conventionalist description of at least some central cases remains useful.
• A few adopt a more holistic view, reconceiving analyticity as an extreme point on a continuum of statements varying in their degree of entrenchment and convention‑dependence.

These internal debates shape how conventionalism is formulated in contemporary philosophy and how it responds to classic objections.

12. Criticisms and Rival Schools

Conventionalism has faced sustained criticism from various philosophical perspectives. Rival schools challenge its claims about the conventional status of logical, mathematical, and scientific principles, as well as its meta‑ethical and political implications.

12.1 Scientific Realism

Scientific realists argue that the success of mature scientific theories is best explained by their approximate truth and by the real existence of the entities they posit. From this standpoint:

• Conventionalism underestimates the constraining power of evidence, especially across theory change.
• Underdetermination is claimed to be less pervasive in practice than conventionalists suggest.
• Conventions may play a role in representation, but the content of laws and structures is said to be discovered rather than chosen.

12.2 Logical Realism and Necessitarianism

Logical realists and necessitarians maintain that the laws of logic are universally and necessarily valid, not optional frameworks. They raise concerns such as:

• Conventions seem to presuppose logical inference; using logic to justify logic appears circular.
• Treating alternative logics as mere choices is said to ignore arguments that certain logics better capture truth‑preserving reasoning or metaphysical necessity.

12.3 Platonism and Non‑Conventional Mathematics

Platonists in mathematics hold that mathematical objects and truths exist independently of our conventions and that mathematicians discover rather than create them. They object that conventionalism:

• Struggles to explain the apparent objectivity and necessity of mathematics.
• Offers a limited account of the unreasonable effectiveness of mathematics in empirical science.
• Risks conflating the choice of axiomatization with the existence of the structures thereby described.

12.4 Moral Realism

In ethics, moral realists contend that moral facts are stance‑independent. They argue that conventionalism:

• Cannot justify strong moral criticism of unjust social practices that are, by hypothesis, widely accepted.
• Has difficulty explaining moral disagreement as more than clash of customs.
• Risks collapsing into relativism or subjectivism, undermining the authority of moral norms.

12.5 Metaphysical Essentialism

Metaphysical essentialists maintain that kinds and properties have intrinsic essences. They see conventionalism about classification and kinds as:

• Overlooking natural joint‑cutting structures revealed by science (e.g., chemical elements, biological species).
• Mistaking our evolving conceptual schemes for the underlying metaphysical reality they aim to track.

12.6 Internal Critiques

Even within broadly sympathetic traditions, critiques arise. Quine famously challenged sharp analytic–synthetic distinctions and the notion of purely conventional truths, promoting holism that blurs the line between framework and empirical content. Some pragmatists argue that conventionalism is too static or rule‑centered, neglecting the dynamic evolution of practices. These debates have pushed conventionalism to more nuanced, often “neo‑conventionalist,” formulations.

13. Syncretism with Pragmatism and Logical Empiricism

Conventionalism did not develop in isolation; it became intertwined with pragmatism and logical empiricism, yielding hybrid positions.

13.1 Pragmatist Affinities

Pragmatism, associated with Peirce, James, and Dewey, emphasizes the role of practical consequences and inquiry practices in shaping concepts and truth. Conventionalism overlaps with pragmatism in several respects:

• Both stress the instrumental role of theories and classifications.
• Both highlight fallibilism and revisability of even central principles.
• Both regard meaning as bound up with use and practical norms.

However, pragmatists sometimes criticize conventionalism for framing norms too much in terms of static rules or linguistic stipulations rather than ongoing experimental adjustment.

13.2 Logical Empiricism and Linguistic Frameworks

Logical empiricists (or positivists) in the Vienna Circle and Berlin School integrated conventionalist ideas into a broader program of:

• Emphasizing logical analysis of language.
• Distinguishing between analytic (convention‑based) and synthetic (empirical) statements.
• Reconstructing scientific theories in formal languages.

Carnap’s notion of a linguistic framework is a paradigmatic syncretic idea: adopting a framework is a pragmatic decision, but within it, statements are objectively true or false. The framework’s logical rules and definitional conventions capture the conventionalist element; observational sentences retain a straightforward empiricist interpretation.

13.3 Reichenbach and the Relativized A Priori

Hans Reichenbach combined neo‑Kantian ideas with conventionalism and logical empiricism. His concept of the relativized a priori:

• Treats coordination principles (e.g., defining simultaneity) as framework‑specific a priori elements.
• Maintains that such elements can change with scientific revolutions, aligning with conventionalism.
• Integrates them within an empiricist methodology, where these principles are adopted partially on pragmatic and empirical grounds.

13.4 Tensions and Mutual Influence

The syncretism produced both convergences and tensions:

Later critiques of logical empiricism (e.g., by Quine and Kuhn) also impacted conventionalist ideas, leading to more holistic and practice‑oriented neo‑conventionalist frameworks that still bear traces of their pragmatic and empiricist ancestry.

14. Influence on Later Analytic and Continental Philosophy

Conventionalism has significantly shaped both analytic and continental traditions, even where later thinkers explicitly rejected or modified its theses.

14.1 Later Analytic Philosophy

In analytic philosophy, conventionalism’s impact is visible in several areas:

• Philosophy of language: The idea that meanings are tied to use and inferential roles influenced ordinary language philosophy and later inferentialist semantics. Even critics of strict conventionalism often accept that linguistic norms play a central role in fixing meaning.
• Meta‑ontology: Neo‑Carnapian approaches treat ontological questions as framework‑relative, shaping debates about “ontological commitment” and deflationary metaphysics.
• Philosophy of logic and mathematics: Discussions of alternative logics and axiomatizations often employ conventionalist themes about rule choice and conceptual engineering.

Quine’s critique reoriented the conversation by questioning analyticity and emphasizing theory holism, yet his view that we can, in principle, revise any statement has affinities with the revisability stressed by conventionalists. Contemporary debates about logical pluralism and conceptual engineering sometimes rearticulate conventionalist motifs in new forms.

14.2 Continental Thought: Structuralism and Post‑Structuralism

In continental philosophy, conventionalist ideas appear in more diffuse ways:

• Structuralism in linguistics and anthropology (Saussure, Lévi‑Strauss) emphasizes the arbitrary nature of the sign and the relational structure of systems—resonant with conventionalist structuralism.
• Post‑structuralist and deconstructive thinkers (e.g., Derrida) explore how meaning arises from differential structures and conventions within discourse rather than from direct reference to an independent essence.

While these movements are not straightforwardly conventionalist and often resist reduction to agreements or explicit rules, they share with conventionalism a focus on constructed structures, contingency, and the non‑naturalness of many categories.

14.3 Philosophy of Science: Kuhn and Beyond

Thomas Kuhn’s account of paradigms and incommensurability in scientific revolutions bears partial resemblance to conventionalism:

• Paradigms define what counts as legitimate problems and solutions.
• Shifts between paradigms involve changes in conceptual frameworks, not just in isolated hypotheses.

However, Kuhn emphasizes historical and sociological dynamics more than explicit conventions. Later philosophers of science, including Bas van Fraassen and structural realists, develop positions that incorporate conventionalist themes—such as framework‑dependence and representational choice—within broader accounts of scientific representation and realism.

14.4 Ongoing Resonances

Beyond these explicit influences, conventionalist ideas continue to inform debates on:

• The normativity of language and logic.
• The status of conceptual schemes in metaphysics.
• The role of social construction in categories such as race, gender, and disability.

These developments often extend or transform conventionalist insights rather than endorsing classical formulations, but the underlying concern with how humanly instituted norms and structures shape knowledge remains central.

15. Contemporary Neo‑Conventionalist Approaches

Contemporary philosophy contains a variety of neo‑conventionalist approaches that revisit classical ideas in light of later developments in logic, philosophy of language, and philosophy of science.

15.1 Framework Pluralism and Logical Pluralism

Many current debates emphasize pluralism about logics, ontologies, or conceptual schemes:

• Logical pluralists argue that more than one logic is correct, relative to different standards or contexts. Some interpret this as a form of conventionalism: communities or theorists may adopt different inference rules depending on their aims (e.g., mathematical proof vs. reasoning about vagueness).
• Ontological pluralists and neo‑Carnapians treat questions about existence (numbers, properties, possible worlds) as framework‑dependent. Choosing a framework is a pragmatic decision; within a framework, quantification and existence claims are straightforward.

These positions echo conventionalism’s stress on framework choice, while often accommodating stronger realist elements than traditional conventionalists did.

15.2 Pragmatic and Inferentialist Neo‑Conventionalism

Some contemporary philosophers, often influenced by pragmatism, articulate conventionalist ideas in inferentialist terms:

• Meanings are constituted by patterns of inference.
• Norms of inference are socially instituted and subject to revision.
• A priori knowledge arises from grasp of these normative inferential roles.

This approach shifts focus from explicit stipulation to the social practices that confer authority on rules, blurring the line between conventionalism and practice‑based accounts of normativity.

15.3 Neo‑Conventionalism in Philosophy of Science

In philosophy of science, neo‑conventionalism appears in:

• Constructive empiricism (van Fraassen), which emphasizes theories as representations chosen for empirical adequacy, with structural and modal features understood partly as modeling choices.
• Renewed interest in modeling, idealization, and simulation, where choices about simplifying assumptions and representational formats are often described in conventionalist terms.
• Discussions of gauge theories, spacetime structure, and symmetries, where some see a conventional element in how mathematical structures map onto physical reality.

These approaches typically accept empirical constraints while acknowledging a substantial role for representational choice.

15.4 Social Ontology and Social Construction

Neo‑conventionalist ideas inform work on social ontology and social construction:

• Institutions, money, borders, and social roles are often analyzed as grounded in collective acceptance of rules or constitutive conventions.
• Some accounts of gender, race, and disability emphasize how social categories are constructed through practices and norms, in ways that echo conventionalist themes about classification.

Here, conventionalism is extended beyond scientific and logical domains to the analysis of social kinds.

15.5 Negotiating Realism and Conventionalism

Many contemporary positions attempt to balance conventionalist insights with realist commitments:

• Recognizing that representation is choice‑laden and practice‑dependent, while also affirming that there are better and worse ways to represent a mind‑independent world.
• Treating conventions as elements of epistemic access rather than as determinants of all facts.

This landscape of neo‑conventionalisms illustrates how the core idea—that some central structures are instituted rather than found—continues to evolve across philosophical subfields.

16. Legacy and Historical Significance

Conventionalism’s legacy lies less in a single enduring doctrine than in a cluster of enduring questions and tools it introduced into philosophy.

16.1 Reframing the A Priori and Framework Dependence

By reinterpreting parts of the a priori as framework‑constituting conventions, conventionalism helped:

• Undermine rigid oppositions between analytic and synthetic, language and world.
• Foster the notion that scientific and mathematical knowledge involve choice among formalisms, not just passive recording of facts.
• Influence later ideas of relativized a priori, paradigms, and conceptual schemes.

These moves reshaped epistemology and philosophy of science throughout the 20th century.

16.2 Impact on Philosophy of Science and Metaphysics

Conventionalism played a key role in:

• Highlighting underdetermination and theory–observation holism.
• Bringing measurement conventions and coordination principles to the foreground.
• Encouraging deflationary and framework‑relative approaches to metaphysical questions.

Even where philosophers reject full‑blown conventionalism, they often retain its diagnostic tools for distinguishing empirical from framework disputes and for analyzing how scientific representations connect to the world.

16.3 Influence on Broader Intellectual Currents

Beyond analytic philosophy, conventionalist themes contributed to:

• Structuralist and post‑structuralist emphases on the constructed nature of meaning and categories.
• Social constructivist analyses of institutions and social kinds.
• Interdisciplinary reflection on how norms, classifications, and models are humanly instituted yet practically indispensable.

In this way, conventionalism has been part of a larger 20th‑century shift toward examining the mediating role of symbols, norms, and practices in knowledge.

16.4 Continuing Relevance

Although classical geometric and logical conventionalism has been modified in light of developments in relativity, logic, and philosophy of language, many of its central concerns persist:

• How much of our most basic knowledge is chosen structure rather than discovered fact?
• What distinguishes non‑arbitrary conventions from mere caprice?
• How should we understand objectivity in domains shaped by human frameworks?

Contemporary neo‑conventionalist and related approaches testify to the ongoing significance of these questions. The historical trajectory of conventionalism—from Poincaré and Duhem through logical empiricism to present debates—has left a durable imprint on how philosophers think about frameworks, norms, and the human contribution to knowledge.