Legal Conventionalism

The Problem of Conventional Foundations

Legal conventionalism begins from a pervasive fact about legal reasoning: legal participants regularly identify legislation, precedents, constitutional instruments, administrative decisions, and customary rules by reference to standards that other participants also use. A lawyer's statement that an enactment is legally valid ordinarily presupposes procedures of enactment, criteria of competence, and institutional understandings that are neither re-established nor defended from first principles on each occasion. A judge applies a source test because it belongs to a continuing practice of adjudication and because other legal actors treat that test as the appropriate one. The philosophical question is what explains the normative significance of this convergence.

The problem arises at several levels. The existence of a legal order calls for an explanation of how historically dispersed acts become parts of one legal system. A claim about legal validity calls for a test that identifies which putative rules belong to that system. A claim about legal content asks what those rules require, permit, or authorize in a concrete situation. A claim about legal authority asks whether participants have reason to defer to the resulting standards. An adequate account must connect these levels without assuming that the same social fact settles every one of them.

Convention offers an attractive solution because a stable common practice can establish the significance of otherwise ordinary human acts. A sequence of marks becomes an official signature under recognized procedures; an assembly's vote becomes legislation under rules accepted by the relevant institutions; a judgment becomes precedent because adjudicators operate within a continuing practice of treating some decisions as reasons for later decisions. These examples illustrate how public standards transform conduct into institutional action. They do not yet establish that all legal content is fixed by convention.

The stakes are both explanatory and political. If law depends on shared practices, legal systems can be understood through observable institutions rather than through a presupposed sovereign metaphysics. Yet an explanation of shared standards must remain sensitive to coercion, disagreement, political rupture, injustice, and the difference between recognizing a legal claim and endorsing its morality. The central task is to identify precisely where convention constitutes law, where it guides law's operation, and where further principles are required (Hart, 2012, chs. V–VI; Marmor, 1998; Green, 1999).

Definition and Boundaries of Legal Conventionalism

Legal conventionalism is a family of jurisprudential positions holding that certain fundamental facts about a legal system are constituted or sustained by established social conventions among relevant participants. In a strong version, conventions establish ultimate legal criteria and thereby ground legal validity. In a narrower version, convention explains the institutional identity of legal sources and the public standards of their use, while other facts and reasons also determine legal content. It is therefore necessary to state the object of every conventionalist claim: the existence of law, the recognition of sources, the content of norms, the interpretation of texts, or the practical authority claimed by institutions.

The definition requires several separations. Legal positivism maintains that law's existence and content depend on social facts rather than the moral merits of the law; a conventionalist theory offers a particular explanation of some of those facts. Not every positivist must explain those foundations as conventions, and conventions can be important to a theorist who rejects positivism about legal content. Customary law concerns practices that themselves may function as legal sources, while conventionalism about the rule of recognition concerns the foundational criteria by which a source is identified as legal. These subjects overlap but have distinct explanatory targets (Green & Adams, 2025; Dickson, 2007).

Nor is legal conventionalism identical with a legal system's adoption of customary procedures or with the thesis that every judicial decision follows established usage. Conventions sometimes select an institutional framework without answering every question that arises inside it. For example, acceptance of a written constitution as an authoritative source may be settled while the meaning of an open-ended constitutional principle remains controversial. A conventionalist explanation of the former supplies no automatic resolution of the latter.

A theoretically useful formulation is conditional: in a legal community, some criteria of institutional action and legal identification are sustained by interdependent, publicly assessable practices of recognition among officials. If the practice is genuinely conventional, convergence itself figures in participants' reasons for following it. If it merely happens to be shared, the term convention requires additional argument. This qualification marks the difference between an explanatory theory and a label for consensus.

Conventions, Customs, Rules, and Agreements

The general philosophy of convention distinguishes an explicit agreement from an established pattern that emerges without an act of collective negotiation. A society may come to drive on one side of the road, use a linguistic expression, or respect a procedure through iterative adjustment. Participants need not have signed a contract or consciously chosen the pattern together. The reason a practice persists may be that each expects others to continue following it and benefits from a predictable common standard (Lewis, 1969; Rescorla, 2024).

A custom is a historically sustained practice; a social norm is a standard participants treat as appropriate and potentially enforce through approval or criticism; a convention is, on influential accounts, a regularity supported by reciprocal expectations and a relevant dependence on what others do. The concepts can overlap, but they are not coextensive. A habit shared by hundreds of people can lack the normative character of a rule. A moral obligation can be understood as binding even when widely violated. An explicit promise can generate a new obligation without a prior convention selecting that very promise. Each case demands a different explanation.

Hart's distinction between being obliged and having an obligation is decisive for this analysis. A person may obey an order to avoid punishment; that pattern of behavior alone does not demonstrate that the person accepts the rule as a standard. When participants use a rule to criticize departures, to justify decisions, and to demand conformity, their attitude displays the internal aspect of rule-following. This internal aspect connects social conduct with normative language without converting every shared habit into a rule (Hart, 2012, ch. V).

A convention also need not be arbitrary in the sense of pointless. The availability of alternatives is central to certain accounts of conventionality: different public standards could have performed the relevant function, yet one has become established. A procedure may be well justified in serving coordination and still be conventional in its particular form. The existence of reasons for choosing a rule does not itself make that rule universal or remove the contingent history of its adoption. Consequently, the assessment of legal conventionalism must distinguish the reasons for establishing conventions, the reasons for continuing them, and the moral assessment of what they accomplish.

Hume and the Conventional Origin of Justice

David Hume offers an essential antecedent in Book III, Part II, Section II of A Treatise of Human Nature, first published with Book III in 1740. Hume begins by asking how rules of justice arise and why people come to attach moral approval to their observance. His explanation starts from restricted resources, variable human generosity, and the advantages of stable possession. A convention of mutual restraint develops as people recognize the reciprocal benefits of respecting one another's possessions. It emerges from a common sense of interest expressed through practice rather than requiring a formal promise or inaugural contract (Hume, 1740, III.ii.2).

The analytical achievement lies in the ordering of explanation. The stability of property is an institutional achievement that has to be explained before a theorist can invoke property rights as if they existed independently of social rules. Hume's account thus shows how some normative relationships depend on an established cooperative structure. The fact that participants benefit from stability helps explain the formation of the structure; continued expectations and public responses help explain its persistence.

Hume's argument is not already a modern theory of constitutional adjudication. His central concern is the artificial virtue of justice and the rules of possession in civil society. His convention develops through social interactions more broadly, whereas Hart's ultimate legal standards are accepted in distinctive ways by institutional officials. The relation is a philosophical genealogy of conventional explanation, rather than the assertion that Hume invented the contemporary rule of recognition.

There is also a limit in Hume's model that later jurisprudence must confront. Shared interest can explain why a general rule of possession is useful, but actual political systems are structured by unequal holdings and unequal power to formulate rules. A stable convention can serve an established pattern of advantage. Hume supplies resources for understanding the origin of order; later legal philosophy must investigate the justification and distributional effects of that order separately. This distinction is central to the subsequent problem of how law can exist through social facts while remaining subject to moral criticism.

From Sovereign Commands to Social Rules

Modern legal positivism emerged in a broader history that includes the political thought of Thomas Hobbes and David Hume and the juridical work of Jeremy Bentham and John Austin. Austin's command theory identified law through the commands of a sovereign habitually obeyed by subjects and backed by sanctions. Its explanatory emphasis fell upon identifiable political authority, regular obedience, and the independence of a law's existence from its moral merits. This was an attempt to isolate the social sources of positive law (Green & Adams, 2025).

The command theory, however, has difficulty capturing the full structure of legal orders. Laws may confer powers rather than impose duties; they may establish offices, create procedures, organize succession, and authorize private persons to enter contracts or make wills. A system can also persist through changes of personnel that would be difficult to explain through the continued command of one determinate sovereign. Law's institutional continuity and internal complexity require an account of shared rules capable of explaining competence, recognition, and change.

Hart's response is to understand a developed legal system through the combination of primary rules governing conduct and secondary rules governing the identification, modification, and application of primary rules. Rules of recognition, change, and adjudication can explain law's systematic form. They make it possible to distinguish a change in government from the disappearance of law and a decision taken by an authorized official from a mere exercise of personal power (Hart, 2012, ch. V).

This development locates the philosophical importance of conventions. Once ultimate legal authority is sought in the operation of socially accepted rules, the question becomes how such rules arise, persist, and bind within the official community. The progression from command to rule does not prove that every foundational rule has a Lewisian conventional structure. It establishes the terrain on which the conventionalist interpretation is possible.

Hart and the Internal Point of View

Hart's social rule theory joins observable regularity to a critical reflective attitude. Participants do more than behave alike; they regard a pattern as a common standard and use it to evaluate conduct. Their criticisms, demands, justifications, and references to what is required are evidence of this attitude. Hart describes this stance as the internal point of view. An observer may describe a practice from outside while participants use the same practice to establish obligations or permissions within it (Hart, 2012, chs. V–VI).

The internal point of view is often confused with moral approval. Hart's argument does not require every official to regard the law as just, nor does it require citizens to experience respect for law as a moral commitment. An official may adopt a rule for prudential, institutional, professional, or traditional reasons. What matters to the existence of the social rule is that it functions as a common public standard among the relevant participants. The attitude is normative in its use and consequences, even when its ultimate motives are mixed.

The distinction explains why predictable conformity alone cannot ground legal validity. A court that repeatedly applies statutes because it fears a ruler's retaliation may display behavioral regularity. If courts take the recognized legislative form as a criterion for correct legal decisions, however, their judgments invoke a standard that can be criticized, appealed to, and used in institutional argument. A jurisprudential account must investigate which of these patterns operates in the system rather than assuming that sanction-backed obedience is equivalent to rule acceptance.

At the same time, the internal point of view generates a problem of circularity. Officials are identified partly by their legal powers, while the foundational rule of recognition is said to exist through the conduct and acceptance of officials. Coleman and subsequent theorists develop this issue by asking whether official identity can be specified through institutions and social roles without assuming the very legal validity the theory aims to explain. The question connects social ontology to the architecture of jurisprudence (Coleman, 2001/2003; Shapiro, 2011).

The Rule of Recognition

The rule of recognition is the most important component of Hart's account for legal conventionalism. In a developed legal order, participants use criteria that identify which norms count as part of the law. These may refer to enactment by a specified legislature, judicial precedent, constitutional requirements, or other practices recognized by the legal system. Their particular content varies across institutions and political histories. Ultimate recognition is a social practice, whose existence is established by what relevant officials accept and do rather than by a higher legal enactment that validates itself (Hart, 2012, ch. VI).

A statement that a statutory provision is valid applies a criterion of validity. The ultimate criterion itself raises a different question: whether there is an effective practice treating that criterion as authoritative. Explaining the existence of this practice is a sociological and philosophical task; applying it is a legal task. Hart's distinction between internal and external statements is therefore a distinction between the use of a standard and a description of the circumstances in which a standard exists.

For the conventionalist, the critical further proposition is that the rule of recognition has conventional structure. Officials use a source criterion partly because others in the relevant community use it and expect its continued use. The convergence establishes a common standard that allows their judgments to belong to a coordinated institutional practice. This claim can explain how legal validity is ultimately grounded in historically contingent social activity (Marmor, 1998; Coleman, 2001/2003).

The proposition does not follow simply from the fact that the rule is social. A standard can be jointly accepted because officials independently judge its content to be correct. A practice can be stable because of coercion or an external constraint. A genuinely conventional explanation needs an account of how others' acceptance is itself among the reasons for acceptance, or of how constitutive rules are sustained by participants' practical engagement in an established institution. The difference between these possibilities drives the debate concerning Hart's legacy.

The Existence and Unity of Legal Systems

A legal system is more than an aggregate of commands. It includes relations of authorization, institutional continuity, source recognition, and procedures for adapting rules to changing circumstances. Hart's combination of primary and secondary rules addresses this unity. For him, a developed legal system exists where conduct rules satisfying the system's ultimate criteria are generally obeyed and the relevant secondary rules are effectively accepted by officials as common public standards of behavior (Hart, 2012, ch. VI).

This institutional division of labor has far-reaching consequences. Ordinary citizens can comply with law without understanding the ultimate validity rules. Judges and other officials, meanwhile, may sustain those foundational standards through their decisions and criticisms. The convention underlying legal validity, if such a convention exists, belongs primarily to a specialized institutional population, not necessarily to everyone who lives under the law.

Legal unity cannot be inferred merely from a geographically concentrated set of courts. Two groups of officials may operate rival authority standards within one territory. Conversely, courts distributed across many locations may belong to one system through shared understandings of jurisdiction and legal source. The conventionalist theory supplies a method of investigating these relations by looking at actual practices of recognition, criticism, and institutional deference.

A further problem concerns continuity during disruption. If a constitution is replaced by revolution or an emergency order, when does the old rule of recognition cease to exist? Hart's framework directs attention to changing official practices but leaves difficult thresholds to be worked out. There may be transitional periods in which the unity of the legal system is contested rather than plainly present or absent. Conventionalism makes the social foundations of legal order visible and must therefore also admit their fragility.

Lewis and Coordination Conventions

David Lewis's Convention: A Philosophical Study (1969) transformed philosophical discussion of conventions by explaining them as regularities that solve recurring coordination problems. When people prefer compatible actions and multiple patterns could secure compatibility, reciprocal expectations can make one pattern self-sustaining. A rule that traffic keeps to one side of the road is a familiar example. Common knowledge and expectations explain why participants find it rational to follow an established pattern (Lewis, 1969).

Lewis's account is attractive for law because legal institutions require coordinated expectations. Legislators, courts, enforcement authorities, litigants, and members of the public must be able to identify which official acts have which consequences. Even when institutions disagree about a substantive decision, they often rely on common procedures for determining which decisions are authoritative and which opportunities for review exist.

Nevertheless, the legal context places pressure on the coordination model. Participants may have strongly conflicting interests in the outcomes of litigation. Constitutional judges do not simply select between equally acceptable equilibria. Rules of recognition can impose institutional duties and define a practice that participants regard as valuable in itself. It is unclear that every official's reason for applying a constitution depends on the prospect of mutual advantage from coordination rather than on fidelity to constitutional principles or professional role.

Lewis's contribution should therefore be understood as a powerful general explanation of one species of convention. Its central insight is that explicit agreement is unnecessary for norm-governed coordination. Its explanatory limitation emerges when law's normative structures do more than select an equilibrium among alternatives. Later theorists preserve the importance of reciprocal practice while investigating conventions that constitute institutional activities instead of merely coordinating behavior within independently specified activities (Marmor, 2009; Rescorla, 2024).

Postema and Legal Coordination

Gerald Postema's 1982 article, "Coordination and Convention at the Foundations of Law," brought the analysis of coordination directly to jurisprudential foundations. The central philosophical problem is whether common legal standards solve practical problems of interaction and thereby explain why institutions can function as a legal order. The research belongs to the development of convention theory beyond models of explicit social agreement (Postema, 1982).

Coordination takes on a distinctive meaning in law. Courts must be able to treat one another's judgments and the acts of legislative institutions as recognizable events within the same normative practice. Common standards reduce uncertainty about institutional competence and enable a continuing system of adjudication and legal change. These effects are important even where officials disagree about the wisdom of a rule or the just outcome of a particular case.

A coordination explanation, however, raises a foundational difficulty: if the relevant participants do not already know which authorities to recognize, how can their practices converge on one public system? Existing institutional structures, historically accumulated habits, and expectations about other officials help answer the question, but the explanation can become circular if all of these are assumed to be legal before the rule of recognition has been established. A successful account must reconstruct the dynamics of convergence without building legal validity into its starting assumptions.

Postema's contribution also exposes a distinction that later debates sometimes obscure. Coordination may be one reason a foundational legal convention is valuable without being the entire criterion for what makes it a convention. A legal source rule can have a coordination function while being sustained by professional commitments and a view of legitimate institutional roles. The presence of coordination benefits is explanatory evidence, rather than conclusive proof that a Lewisian account exhausts the foundations of legal practice.

Coleman and the Conventionality Thesis

Jules Coleman develops a sophisticated conventionalist account within legal positivism. His treatment in The Practice of Principle investigates how legal authority is made possible by a particular structure of social practice and defends the possibility that a rule of recognition imposes duties on officials. The philosophical issue is not simply whether judges happen to converge on tests of validity, but how their shared conduct constitutes a standard to which they can hold one another accountable (Coleman, 2001/2003, lecture 7).

Coleman's account directs attention to the difference between the existence of a rule and the reasons a participant might have to comply with it. A legal norm can be constituted by a social practice whose members use it as a standard, while the broader moral justifiability of conforming to the norm remains an independent issue. The conventionality thesis concerns the institutional conditions of legality and the normativity internal to institutional roles. It does not automatically derive a general moral duty from the existence of a social convention.

The possibility of a duty-imposing rule of recognition is theoretically important because the rule's work is not exhausted by classifying statutes as valid. Officials may criticize decisions that depart from accepted criteria and regard adherence to those criteria as a professional responsibility. Explaining this critical practice requires more than registering behavioral frequencies. It requires an account of how an established rule can give participants institutional reasons within a practice.

A foundational challenge persists: do the obligations of officials exist because of the convention or do they rest on independent moral duties concerning fidelity, fairness, or legitimate authority? Coleman gives the conventionalist a route for explaining institutional duties without equating them with ultimate moral reasons. A complete theory must still identify the scope of these duties and explain how the institutional community itself is constituted.

Marmor and Constitutive Conventions

Andrei Marmor's 1998 essay "Legal Conventionalism" explicitly connects two questions: whether rules of recognition exist along Hart's lines, and how law can be an autonomous practice. Marmor argues that a suitable theory of conventions can explain the practice of recognizing legal sources and the partial autonomy of law. In Social Conventions: From Language to Law (2009), he develops a wider account that distinguishes conventions of coordination from conventions that constitute social practices (Marmor, 1998, 2009).

A constitutive convention helps establish what counts as participating in a practice. Consider a game whose rules identify pieces, permitted moves, and winning conditions. Participants coordinate within the game, but its constitutive rules also determine what the game is. Their normative role is internal to an institution whose form has been established through social practices. This provides an alternative to explaining every convention as the solution to a pre-existing coordination problem.

Legal institutions resemble such practices in relevant respects. Rules can determine who may legislate, how judgments acquire precedential standing, and which types of official action produce legally significant consequences. Once accepted, the rules generate institutional categories that participants can use to make and contest legal claims. They make certain forms of action possible by defining their legal significance.

Marmor's analogy must be handled with care. Unlike a voluntary game, a legal order can govern people who did not choose to participate and may impose severe sanctions. Explaining how an institution constitutes legal relations does not establish the moral legitimacy of imposing those relations. The constitutive character of official conventions supports a theory of legal ontology, while legal authority and coercive justification remain subjects for independent evaluation.

Deep and Surface Conventions

Marmor's later analysis introduces a distinction between deep and surface conventions. Surface conventions concern more specific and replaceable arrangements within a social practice. Deep conventions concern its more general constitutive organization. The distinction helps explain how a practice can change many of its operational details while remaining recognizable as the same institution (Marmor, 2009).

Applied to law, specific conventions might concern formats of legal citation, courtroom etiquette, or standard ways of recording official acts. More fundamental practices govern the identification of authoritative institutions, valid enactments, and appropriate modes of legal reasoning. A legal system's history can include changes in surface procedures without a complete replacement of foundational institutional understandings.

Yet the terms deep and surface do not automatically identify a universal hierarchy. What is foundational in one historical legal system may be secondary in another. The precise role of a practice must be established by examining how it constitutes recognizable legal actions, how participants enforce it, and whether alternatives could be substituted without changing the institution's identity. This methodological caution preserves the explanatory value of the distinction.

The deep–surface relation also clarifies the scope of conventional autonomy. If a convention constitutes an authoritative legal source, internal legal decisions can be assessed against that source without resolving every dispute about ultimate moral value. Such autonomy remains partial: constitutional interpretation, legal change, and the justification of authority connect the practice to political and moral reasoning. Marmor's contribution is therefore most powerful when understood as specifying the institutional dependence of law rather than establishing the self-sufficiency of the legal domain.

Dickson and the Limits of the Conventionalist Reading

Julie Dickson's 2007 article asks whether the rule of recognition is genuinely a conventional rule. Her historical argument questions the inference from Hart's original account of social rules to the strong thesis that he understood the rule of recognition in conventionalist terms. She then examines the apparent conventionalist turn in Hart's Postscript and challenges the strength of the evidence that such a commitment was essential to his theory (Dickson, 2007).

The distinction matters because a claim about Hart's own position is a matter of textual and intellectual history, while the claim that conventionalism offers the best reconstruction of his social rule theory is an independent philosophical proposal. A theory can be Hartian without every additional premise being found in Hart's original text. Confusing those claims hides the actual work performed by later theorists.

Dickson also investigates Marmor's constitutive conventions. The critical issue is whether an account that emphasizes practices constituting an institution provides the distinctive reasons-dependent structure expected of a convention. If officials follow recognition rules because they regard them as legally or morally appropriate regardless of what others do, their convergence may not display the conventionality required by the theory. A social foundation and a convention are different philosophical descriptions unless the link is explained.

The strongest version of Dickson's challenge is explanatory rather than terminological. It asks the conventionalist to say what would be lost if the foundational rule were characterized as a social rule accepted for diverse reasons rather than as a convention. An adequate reply must show that the interdependence of official acceptance has a genuinely constitutive role, not merely that everyone shares a practice. This challenge remains central to contemporary analysis.

Reasons for Compliance and Official Acceptance

The normative structure of a legal convention involves at least three questions: why does a person conform, why is conformity an internal standard of correctness, and why should the standard receive moral respect? Distinguishing these questions prevents a common inference from behavioral convergence to justified obedience. The first concerns motivation, the second institutional normativity, and the third political and moral justification.

The official who invokes a shared source criterion may have several motives. She may believe the criterion is constitutionally correct, respect a professional duty, anticipate review by a higher court, or value the predictable operation of institutions. A convention can persist through these heterogeneous motivations. The explanatory question is whether others' use of the criterion supplies a relevant reason for her continued use, especially when alternative criteria are available.

This dependence need not be reducible to self-interest. In professional institutions, mutual recognition can form part of what it means to discharge one's office competently. A judge who ignores the recognized mode of enactment may be criticized for failing to act as a judge under the system's rules. Institutional standards can thus structure reasons internal to a practice even when participants disagree about the ultimate legitimacy of the institution.

The critical boundary is that practice-internal reasons may fail when judged against external considerations. A convention that maintains discriminatory exclusions, entrenches arbitrary power, or removes meaningful legal challenge can exist and operate while being morally objectionable. The distinction between social existence and moral adequacy preserves both the explanatory force of legal conventionalism and the possibility of principled resistance.

Legal Sources and Conventional Determination

Sources of law are the institutional acts or materials that a legal order treats as capable of determining legal norms. Legislation, precedent, constitutional texts, delegated regulations, and customs acquire that standing through historically developed institutional structures. Conventionalist analysis asks how the selection of these sources is made public, stable, and recognizable. A source rule is part of law's infrastructure of identification (Hart, 2012, ch. VI).

To say that convention selects sources is to say that established practice determines the legal relevance of certain acts. It does not follow that a convention exhaustively settles everything contained in those acts. A legislature can enact an authoritative text whose operative meaning is disputed. A court can issue a binding judgment whose ratio must be reconstructed. A customary rule can be acknowledged as a source while its precise content remains uncertain.

This distinction between source identification and content determination is especially important because legal reasoning constantly moves between them. Participants often agree that a statute is authoritative and disagree over whether its wording covers a novel situation. The dispute can be serious even though the foundational source convention remains intact. A theory that conflates the agreement on source with agreement on outcome misunderstands the structure of legal practice.

The most defensible conventionalist proposition is consequently layered. Conventions constitute many of the institutional facts that make a source recognizable. Source materials, linguistic practices, interpretive methods, procedural rules, and additional norms help determine legal propositions. The dependence of legal content on convention is real and sometimes decisive; its degree varies with the kind of legal claim under consideration.

Language, Meaning, and Interpretation

Legal practices operate through language, including statutes, judgments, declarations, and formally recorded acts. Language itself involves conventions, but the conventionality of linguistic communication does not imply that every fact about meaning or interpretation is chosen by convention. A term's use may be stabilized by practice while its application raises semantic, pragmatic, factual, and evaluative questions. The theory of legal conventions intersects here with philosophy of language (Lewis, 1969; Marmor, 2009; Endicott, 2021).

An enacted sentence is both a linguistic artifact and an institutional act. Its legal force depends on recognized procedures of enactment. Its content depends on the words used, relevant context, established interpretive principles, and the legal consequences attached to it. These dimensions can be analytically separated even when they interact in actual reasoning. A validly enacted text can be ambiguous; an unambiguous statement can lack the status of an authorized rule.

Rules of interpretation can themselves be conventional in some respects. Courts may share canons concerning textual context, precedent, or ordinary meaning. Nevertheless, the application of those standards can require judgment about purpose, coherence, justice, and consequences. In particular, abstract legal terms often refer to substantive standards whose assessment cannot be accomplished simply by discovering that a linguistic community has agreed to use the term.

A complete conventionalist theory must therefore be modest about semantic determinacy. Shared language makes legal communication possible, while the interpretation of law develops through structured reasoning within contested institutions. The existence of shared source criteria is consistent with genuine disagreement over what a legal proposition requires. A sound theory should explain how ordinary communication, institutional authority, and interpretive controversy coexist.

Dworkin and Theoretical Disagreement

Ronald Dworkin's Law's Empire (1986) challenges the view that legal propositions depend on common criteria of validity shared by officials. He distinguishes disagreements over the application of agreed criteria from disagreements about the grounds of law themselves. Lawyers may agree on historical events yet contest whether those events determine the law. Dworkin treats such theoretical disagreement as a fundamental feature of jurisprudence rather than an occasional defect in legal administration (Dworkin, 1986, ch. 1).

The challenge is especially powerful against simple conventionalism. If a convention fixes all criteria for legal truth, how can competent participants disagree about the criteria without merely misunderstanding their own practice? Dworkin maintains that interpretation aims to present legal practice in a way that fits its history and gives it the best available justification. Legal argument is therefore interpretive and evaluative in a manner that a purely shared-criteria model may fail to capture.

A conventionalist reply can distinguish agreement at the level of institutional sources from disagreement about the principles or implications that govern their interpretation. The fact that officials accept enacted statutes as legal sources does not require their agreement about every interpretive doctrine. Nor does the existence of disputed cases show that agreement is absent throughout routine legal activity. Many legal interactions proceed under settled rules without appellate controversy (Green & Adams, 2025).

This reply establishes the possibility of conventional foundations alongside theoretical disagreement, but it leaves questions about boundary cases. Some disputes directly concern whether a convention exists or should be treated as authoritative. Others reveal that the supposedly shared criterion has multiple rival formulations. The conventionalist must allow for degrees of convergence, historically shifting practices, and contested foundational standards rather than assuming a complete and transparent consensus.

Dworkin's critique remains a substantive warning: where legal argument changes the recognized grounds of decision through moral interpretation, a theory of legal content needs more than a record of official convergence. Conventional explanation may remain necessary to identify institutional materials while interpretive justification remains essential to explaining their normative significance.

Inclusive Positivism and Moral Criteria

The debate between inclusive and exclusive legal positivism concerns whether moral criteria can be part of the conditions of legal validity. Inclusive positivism permits a legal system's social sources to incorporate moral standards as criteria of validity. Exclusive positivism holds that legal validity is fixed through social sources without morality forming a necessary part of the source test. The conventionalist issue is whether officials can conventionally recognize a criterion that directs them to moral reasoning (Green & Adams, 2025).

Suppose a constitution authoritatively prohibits cruel punishment. Officials may agree that the constitutional provision governs, and this agreement can be explained in terms of recognition practices. But the moral content of cruelty is not necessarily determined by the fact that officials recognize the constitutional provision. The conventional source establishes an obligation to use a standard; the standard's application can require moral assessment.

This case reveals the importance of distinguishing a convention's content from the content of whatever that convention authorizes or incorporates. A convention may direct participants to a reason whose validity is not constituted by the convention itself. In the same way, a legal rule might adopt a technical measure, a factual threshold, or a moral concept that has independent criteria of assessment.

Legal conventionalism therefore has different implications depending on the version of positivism with which it is combined. A strong exclusive version aims to show that institutional facts entirely determine legal content. An inclusive version can hold that the convention selects moral tests which then play a genuine role in determining specific legal propositions. The conventional structure of legal identification alone does not decide which theory is correct.

Raz and the Authority of Sources

Joseph Raz's philosophy of law emphasizes the role of authoritative sources and the way law purports to provide reasons for action. His essays on the authority of law and his sources thesis insist on the significance of identifiable institutional sources for law's practical role. A source-based account can explain how legal standards are recognized without reopening every substantive dispute that the law is meant to settle (Raz, 1979/2009).

The connection with legal conventionalism is strong but incomplete. Institutions must possess accepted ways of identifying which acts count as legally authoritative. Shared source recognition can sustain the intelligibility and continuity of law. Yet Raz's account of authority asks a further normative question: what makes a purportedly authoritative directive capable of serving subjects' reasons? The presence of an accepted institutional convention is not a complete answer.

A rule of recognition can also be analyzed without attributing to it all the functions of law. It specifies criteria of legal membership but does not automatically settle whether a legal official is morally entitled to enforce a rule or whether citizens ought to comply. Raz's work makes that distinction especially important because legal authority is connected with the mediation of reasons, not simply with the social facts by which sources are identified.

This comparison shows how conventionalism can form an explanatory component of legal positivism without exhausting an account of law's practical normativity. Social conventions make sources publicly recognizable; philosophical analysis of authority assesses what such recognition can justify.

Shapiro and the Planning Structure of Law

Scott Shapiro's Legality (2011) reconstructs law through the activity of social planning. Legal institutions provide complex, authoritative plans and planlike norms for organizing conduct in circumstances where decentralized judgment can generate significant problems. A legal system can accordingly be understood as a structured practice of coordinating decisions and allocating authority through interconnected plans (Shapiro, 2011).

The planning account shares important commitments with conventionalism: law has social foundations, is institutionally organized, and depends on the conduct and attitudes of relevant participants. Yet plans have functions and structures that are not reducible to the existence of any one convention. They can guide activity prospectively, distribute tasks, and settle questions in advance. An authoritative planning system also raises its own problem of who is empowered to plan for whom.

Shapiro's model helps reveal the difference between explaining the conditions of institutional existence and explaining the practical operation of law. A convention might identify authorized planners; plans then regulate action through content that may be more precise, complex, or revisable than the convention selecting the institutional role. As in the debate over constitutive conventions, the system's foundational arrangements are necessary to its identity without being identical with every legal directive it produces.

A further question concerns the nature of the planning authority. The official recognition of a planning institution can create internal legal consequences, but the normative legitimacy of subordinating other people's choices to such plans requires independent justification. Shapiro's framework and conventionalist jurisprudence converge on the importance of social organization while differing in the explanatory weight given to conventional rules and planning structures.

Institutional Facts and Legal Ontology

Legal conventionalism is also a theory about institutional existence. A vote, an official seal, a signed document, or a court order acquires legal significance because recognized institutional conditions are satisfied. John Searle's analysis of institutional facts offers a complementary vocabulary: constitutive rules and collective recognition allow certain things to count as other things within an institutional context (Searle, 1995).

This ontological approach explains how legal statuses can be real and socially dependent. The fact that a corporation exists, a judgment binds an institution, or a regulation has been enacted cannot be read directly from the physical properties of paper, screens, or human movement. Its existence depends on norms defining recognizable institutional acts. The consequences of such facts can nevertheless be durable, public, and consequential.

Institutional ontology also clarifies a limit. The existence of a legal status is different from the truth of factual propositions about the world. A convention can designate a tribunal and determine its jurisdiction; it does not thereby ensure that the tribunal's factual judgments are accurate. It can create the office of a legal decision maker; it does not guarantee that the official's reasons are adequate. Conventional constitution and epistemic justification remain different explanatory relations.

An account of legal ontology must examine the identity and persistence conditions of practices. Who counts as an official, what kinds of acts count as lawmaking, and how long does recognition remain effective after political disruption? Answers involve networks of roles, expectations, and critical practices. These networks may be stable without being immune to reform, and they may be institutionally effective while morally contestable.

Law, Morality, and the Claim to Authority

The foundational role of convention does not resolve the relation between legal validity and morality. Legal validity identifies a norm as part of a legal order; moral adequacy evaluates the norm or the reasons for following it. A legal system may contain deeply unjust rules. The fact that officials can identify those rules through shared criteria is an explanation of legal status, not a verdict about justice (Hart, 2012; Green & Adams, 2025).

The conventionalist faces a characteristic normative temptation. Because adherence to a common rule can support predictability and cooperation, it may seem that every established practice supplies a moral reason for conformity. But the value of coordinated conduct depends on its object and consequences. A coordinated system that systematically violates rights can be more efficient at injustice than a fragmented one. Institutional convergence therefore offers limited justificatory support.

Lon Fuller's argument concerning the internal morality of law presses a different concern. Legal government depends on generality, publicity, intelligibility, consistency, and other conditions of rule-guided action. These requirements express features of law's practical form and suggest that certain standards of legality cannot be ignored when evaluating an institution. The conventions of officials must operate in a framework where subjects can understand what the law requires (Fuller, 1964).

Legal conventionalism can acknowledge such requirements without treating convention as morally self-validating. Conventions create and stabilize parts of the legal infrastructure. That infrastructure can be criticized for failures of publicity, equality, responsiveness, and justification. Keeping explanatory and evaluative questions distinct allows the philosophical study of law to investigate both its social foundations and its normative responsibilities.

Greenberg and the Determination of Legal Content

Mark Greenberg's "How Facts Make Law" (2004) questions how nonnormative facts can determine the content of legal obligations. The mere fact that an institution produced a text or acted in a certain way does not explain, without further premises, why one legal proposition rather than another follows. The challenge concerns the metaphysical relation between law-determining social practices and legal content (Greenberg, 2004).

Greenberg's later moral impact theory gives a competing answer. On that view, the content of law consists in certain moral obligations generated through the morally relevant impact of legal institutions' actions. Legislative and judicial acts can change people's circumstances, expectations, and available options; their legal significance depends on the moral consequences of these changes. The theory offers a challenge to models treating institutional communication or convention as sufficient to determine all legal content (Greenberg, 2014).

The conventionalist may agree that conventions alone rarely specify everything that follows from a legal act while resisting the claim that moral impact constitutes legal content generally. An official standard may determine that a text was enacted; an interpretive practice may guide its application; background legal norms may settle priority among authorities. Whether such factors yield a complete account is a substantive dispute, not a matter settled by the label convention.

Greenberg's objection helps refine the conventionalist thesis. Establishing the existence of a source is one relation; determining a particular legal proposition through that source is another. Conventionalism has an especially strong account of the former and a more contested account of the latter. Its explanatory ambitions are strongest when it makes the steps of determination explicit rather than treating social facts as magically producing fully specified normative content.

Customary Law, Plurality, and Legal Change

The significance of convention extends beyond centralized legislation. Customary legal practices may be recognized through continuing social use and institutional acceptance. Some legal orders contain multiple overlapping communities of interpretation and authority. Legal pluralism therefore tests the assumption that one integrated group of officials always possesses a single, uncontested ultimate rule of recognition.

A convention-based approach can describe multiple local standards and their interactions. A customary community may recognize a practice as binding through public participation, while state institutions apply a different set of criteria for acknowledging it as enforceable law. A transnational regulatory regime may depend on recurring institutional recognition without a single sovereign legislature. These possibilities require careful attention to which legal order a particular validity claim addresses.

Conventions also change. Officials may gradually modify their understanding of precedent, jurisdiction, or constitutional authority. Such transformations need not be accompanied by a formal amendment to a written rule. Change can occur when a once-deviant mode of reasoning acquires sufficient public recognition to become a standard of the institution. This is a source of legal adaptation and a potential source of uncertainty.

The conventionalist must specify when repeated deviations amount to a new practice rather than failures to obey an existing one. No simple numerical threshold settles the matter. What counts is the structure of critical attitudes, the institutional relationships among participants, and the degree to which the new practice is used as a public criterion. The theory is therefore sensitive to history, power, institutional hierarchy, and patterns of contestation.

Conventions Under Institutional Conflict

A foundational legal convention is easiest to identify when official practices converge. Its philosophical character becomes more visible during disputes about institutional authority. Constitutional emergencies, disputed successions, judicial resistance to executive measures, and competing courts can produce incompatible claims about the very sources of valid law. In such cases the participants do not merely disagree about the application of a shared rule; they may contest which rule ought to govern.

One response is to declare that there is temporarily no unified convention. Another is to identify overlapping conventions sustained by different institutions. A third is to analyze a historically changing rule whose application is contested but whose general identity persists. The choice among these accounts cannot be made solely by observing who possesses immediate physical power. Coercion affects legal practice, but the existence of a common rule also depends on the attitudes and conduct of relevant participants.

Institutional conflict reveals a tension between descriptive accuracy and normative aspiration. A constitutional court may defend an established source standard against officials who seek to alter it. Its reasoning may appeal to continuity, public commitments, and justice. A conventionalist should describe the practices actually sustaining institutional authority while analyzing the reasons offered for preservation or change. Neither history nor moral argument can be deleted from the account.

The central lesson is that convention is a condition of possible legal stability, not a guarantee of it. Its existence is historically contingent, socially supported, and sometimes disputed at the very moment when legal authority matters most. A jurisprudence that begins with official agreement must explain what its theory says when agreement becomes unstable.

The Normative Risks of Official Convergence

The fact that a group of officials shares legal standards establishes an institutional perspective. It does not establish the social representativeness of that perspective. A legal system can be administered by a small professional community whose assumptions are insulated from the experiences and interests of the people it governs. Hart's division between official acceptance and general obedience makes this possibility structurally intelligible (Hart, 2012, ch. VI; Green & Adams, 2025).

Conventionalism therefore raises questions about inclusion. Whose convergence matters when identifying the relevant convention? Judges may accept one source criterion while marginalized communities recognize different normative authorities. Professional consensus may conceal exclusions from participation and unequal access to effective contestation. The social reality of law includes these asymmetries even when a doctrinal account of validity focuses on officials.

A strong philosophical analysis must distinguish the rule's internal coherence from its political legitimacy. An institution can consistently apply a convention and nevertheless deny fair hearings, reproduce discrimination, or prevent affected parties from challenging its premises. The existence of an identifiable rule of recognition may even allow such practices to operate with considerable efficiency.

This critical perspective enriches rather than invalidates explanatory conventionalism. It directs the theorist to investigate how shared legal standards are generated, which actors sustain them, how dissent is treated, and whether institutions provide means of public revision. A convention is not politically innocent simply because its operation is technically well coordinated.

Contemporary Research and Interdisciplinary Connections

Contemporary scholarship about social norms has developed increasingly precise analyses of empirical expectations, normative expectations, conditional preferences, and game-theoretic equilibria. These approaches help explain how practices emerge and persist, why some patterns remain stable without explicit enforcement, and why other patterns require social sanctions or institutional support. They also reinforce the need to distinguish a convention from a moral norm or a merely descriptive regularity (Bicchieri, 2006; Bicchieri et al., 2023).

Philosophy of language contributes a parallel inquiry into how public meaning is sustained through use and convention. The lessons for law are substantial: linguistic regularities make legislative and judicial communication possible, while context and interpretive reasoning influence the content derived from legal texts. The theory of institutions contributes explanations of role-dependent facts, authorized acts, and socially constituted statuses.

Political philosophy examines the justification of authority, consent, representation, and the obligation to obey. Sociology of institutions investigates how professional communities reproduce standards through training, precedent, hierarchy, and reciprocal expectations. These fields illuminate different levels of the same legal practice. Their contributions should be integrated without reducing legal norms either to strategic equilibria or to disembodied moral propositions.

The digital transformation of institutions makes these questions increasingly concrete. Electronic signatures, automated administrative acts, digital registries, and computationally assisted adjudication depend on conventions that determine what counts as an authenticated act, an authoritative record, or a reviewable decision. A system can adopt new technological media while retaining older foundations of legal authorization. The existence of a machine-generated output does not establish its legal effect without a normative framework assigning institutional significance to it.

The Artificial Era broadens the ontological question of how institutional status is assigned to acts and agents, but it does not settle current positive law through a philosophical declaration. An account of legal conventionalism must assess actual source rules and publicly established procedures when examining whether an automated act has legal force. That requirement follows from the theory of legal identification itself.

A Reconstruction of Conventional Legal Determination

The foregoing arguments support a layered reconstruction of legal conventionalism. First, a legal practice requires institutionally intelligible roles and criteria of action. Second, participants sustain these criteria through publicly observable conduct and critical attitudes. Third, where continued participation depends in a relevant way on others' recognition, the practice has a conventional dimension. Fourth, the resulting criteria constitute certain legal sources or institutional powers. Fifth, those sources interact with linguistic meaning, interpretive reasoning, and other norms to determine particular legal propositions. Sixth, moral and political evaluation asks whether the resulting institutions deserve obedience or reform.

Each stage has an independent test. Institutional existence is tested through the actual operation of authority-constituting practices. Conventionality is tested through the role of reciprocity and practice-dependent reasons. Source recognition is tested through the standards participants use in identifying authoritative acts. Legal content is tested by reconstructing the relevant materials and rules of interpretation. Moral legitimacy is evaluated through reasons that can assess the practice from beyond its own internal standards.

This reconstruction preserves the strongest insight of Hart: law is an institutional practice whose foundations are sustained in the conduct and attitudes of officials. It preserves Lewis's insight that conventions need not originate in explicit agreement. It incorporates Marmor's insight that constitutive conventions can determine what an institution is. It takes Dickson's warning seriously by demanding evidence that a foundational social rule has genuinely conventional structure. It accepts Dworkin's demonstration that legal argument can concern the grounds of law and Greenberg's demand for an account of how social facts determine normative content.

The synthesis is deliberately bounded. Legal conventionalism is strongest as an explanation of the institutional constitution, continuity, and recognition of legal sources. It becomes more demanding when it purports to explain the complete content of all law, and it cannot by itself establish the moral authority of law. This is a philosophical result derived from distinguishing several kinds of dependence rather than a newly proclaimed canonical theory.

Outstanding Philosophical Questions

The first unresolved question concerns criteria for conventionality. How much dependence on other officials' acceptance is necessary for a recognition rule to count as conventional, and how should that dependence be identified empirically? Legal practices can persist through mixtures of habit, professional conviction, loyalty, strategic adaptation, and coercion. A refined conventionalist account needs an explanatory test that does not classify every shared rule as a convention by definition.

The second concerns the individuation of a legal system. When different institutional groups recognize partly incompatible authority standards, does conventionalism describe one conflicted system, several overlapping systems, or a transition between orders? The answer is consequential for constitutional rupture, international institutions, and legal pluralism. A general jurisprudence must specify the relevant unit of social practice without assuming the conclusion.

The third concerns legal content. How far do recognized sources and conventions of interpretation determine legally correct answers, especially where contested constitutional values or broad standards are involved? The relationship among enacted text, communicative intentions, judicial reasoning, moral principles, and institutional precedent remains contested. The argument about legal conventionalism is inseparable at this point from the broader disagreement between positivism and interpretivism.

The fourth concerns the normativity of recognition. If official convergence makes a source authoritative within law, what reason, if any, does this give an ordinary subject to comply? What should an official do when the established source convention conflicts with a fundamental moral duty? Legal philosophy cannot settle these matters by relabeling institutional acceptance as moral legitimacy.

The fifth concerns institutional change under technological and social transformation. How can an inherited recognition practice authorize newly automated forms of action, and who is entitled to contest the resulting assignments of institutional status? The problem tests the portability of conventional foundations across changing media and kinds of agents. The answer requires concrete analysis of actual legal institutions alongside systematic philosophical argument.

Conclusion

Legal conventionalism establishes a fundamental insight about law: the identification of legal sources and the continuity of legal institutions depend in important respects on publicly sustained practices of recognition. A legal order does not arise solely through isolated commands or texts; it operates through shared standards that determine who may act, which acts count, and how institutional claims can be assessed. The social foundations of law are visible in the common practices of officials, in the critical language they use, and in the procedures through which they recognize and challenge legal authority.

The historical reconstruction reveals a continuous development of this problem. Hume explains how conventions can generate stable forms of social order without explicit agreements. Lewis specifies the logic of coordination and reciprocal expectations. Hart identifies the internal aspect of social rules and the foundational role of the rule of recognition. Postema, Coleman, and Marmor develop contrasting accounts of convention in legal practice. Dickson asks whether these accounts genuinely describe Hart's position and whether their conventionality claims add explanatory content. Dworkin, Raz, Shapiro, and Greenberg expose further demands concerning legal disagreement, authority, planning, and content determination.

The research supports an account with definite boundaries. Conventions are central to institutional constitution and the identification of legal sources; they can influence the content of legal norms through source selection and interpretive practice; they do not independently settle every legal disagreement or justify every legal obligation. The existence of shared standards, the determination of legal propositions, and the moral assessment of legal authority are distinguishable questions whose relations must be established through argument.

The resulting philosophical position treats legal conventionalism as a substantive theory of the social constitution of legal order. Its strength lies in explaining how legal practices become intelligible, durable, and publicly contestable. Its remaining difficulties concern the exact nature of convention, the transition from social practice to normative content, the persistence of law during conflict, and the legitimacy of authority exercised under rules that people may have had no part in choosing. Those questions define the continuing research program.