Lon L FullerEdit
Lon L. Fuller was a central figure in 20th-century legal philosophy, whose work helped shape enduring debates over what makes law legitimate and how societies ought to constrain political power. He is best known for arguing that law cannot be reduced to brute power or mere social fact; rather, law carries an “inner morality” that expresses itself through the way legal rules are made, announced, and administered. This idea sits at the intersection of formal legality and moral accountability, a combination that has appealed to many readers who prize predictability, legitimacy, and restraint in government.
Fuller’s most influential work, The Morality of Law, articulates a theory of legality that emphasizes procedural and moral requirements that law must meet to count as law at all. He argued that law is not simply what rulers say or what the majority allows; it is a system of rules whose authority rests on how those rules are internalized and practiced. In particular, he outlined a cluster of features—often summarized as an “inner morality of law”—that make law believable, workable, and just in practice. These ideas are closely associated with a broader tradition that reads the rule of law as a check on arbitrary power and a guard against tyranny.
In Fuller’s account, law gains legitimacy only when it satisfies certain conditions that govern both the form and the administration of rules. The core features commonly described include generality, publicity, prospectivity, intelligibility, noncontradiction, constancy, congruence between declared rules and actual enforcement, and feasibility of compliance. When a legal system satisfies these criteria, it provides subjects with reliable expectations, conditions under which officials can be held to account, and a stabilizing framework for social cooperation. When those features fail, Fuller warned, law ceases to function as law and becomes instrumental power or mere fiat.
Core ideas and how they fit into broader debates
Inner morality of law: Fuller argued that legality entails more than the mere existence of rules. A legal system must exhibit a certain moral structure in how rules are formulated and applied. This view places procedural and normative requirements at the center of legal legitimacy, arguing that citizens’ ability to anticipate how the law will operate rests on the system’s internal coherence. See inner morality of law.
General influence on the rule of law: Fuller’s emphasis on predictability, clarity, and consistency has reinforced the popular intuition that the rule of law is essential for orderly markets, stable governance, and protection of property rights. His approach aligns with broad, capacity-building views of constitutional order that stress constraints on rulers and predictable governance. See rule of law.
Relation to natural law and legal positivism: Fuller stood in a long-running debate with legal positivists who insist that law is a system of social facts and commands independent of morality. Fuller challenged the idea that legality can be fully understood without considerations of moral appropriateness, while still resisting any claim that law is reducible to moral law alone. See natural law and legal positivism.
The Morality of Law and the conscience of administration: Fuller’s framework emphasizes how laws are taught, cited, and enforced, not simply what they decree. This has implications for administrative law, judicial administration, and the everyday functioning of courts and bureaucracies. See The Morality of Law.
reception, controversy, and debates
Critics from the positivist school argued that Fuller’s “inner morality” introduces morality into the definition of law itself and thus risks conflating two distinct spheres: what the state declares versus what morality requires. H. L. A. Hart, a leading figure in legal positivism, famously contested the idea that morality can straightforwardly define or determine legality, insisting instead on a separation between what the law is and what the law ought to be. See H. L. A. Hart and legal positivism.
Critics from natural-law or liberal-constitutional perspectives have also debated Fuller’s account. Some contend that moral criteria for law may be too late or too ambiguous to provide a reliable watchdog against political abuse, especially in moments of national crisis or mass injustice. Others defend Fuller’s insistence that lawful critique must operate through the structure of public, knowable rules rather than ad hoc moral judgments.
From a contemporary, right-leaning vantage, Fuller’s emphasis on predictable, limited government and constraint on arbitrary power is a powerful defense of the rule of law as a bulwark against tyranny and bureaucratic overreach. Critics may argue that his framework risks idealizing law’s moral elements or underestimating political necessity in difficult situations. Yet even critics concede that a live connection between law and moral justification can help prevent rulers from hiding behind procedural formalities while acting capriciously.
The charge that Fuller’s framework is “romantic” about morality often centers on the tension between ideal procedural requirements and the messy realities of political life. Proponents reply that robust procedural norms—when properly implemented—provide a nonpartisan, objective standard that limits power regardless of which faction controls the state. They argue that dismissing these norms risks sliding toward capricious governance, where rules bend to expediency rather than justice.
Legacy and influence
Fuller’s work helped fuse concerns about justice, governance, and the practical operation of legal systems. His insistence that law must be intelligible, publicly known, and consistently applied has informed critiques and defenses of the rule of law across constitutional systems, including debates about how courts should interpret and enforce statutes and how administrative agencies should behave. The ideas remain formative in discussions of jurisprudence, and his work is often consulted in conversations about the proper boundaries of governmental power and the legitimate reach of legal institutions.
See also