Hans Kelsen

1. Introduction

Hans Kelsen (1881–1973) is widely regarded as one of the central figures of twentieth‑century legal philosophy. His main contribution, the Pure Theory of Law (Reine Rechtslehre), offers a highly formal, norm‑centered account of what law is, aiming to separate legal science from morality, politics, sociology, and psychology. Within this framework, law is conceived as a hierarchical system of norms (Stufenbau des Rechts), whose validity ultimately rests on a presupposed Basic Norm (Grundnorm).

The entry of which this section is a part examines Kelsen’s life, intellectual formation, and major writings, and then reconstructs the core elements of the Pure Theory of Law: its concept of legal normativity, its understanding of validity (Geltung), and its explanation of the unity of a legal system. It also outlines Kelsen’s contributions to constitutional theory, democratic theory, and international law, and situates his ideas in debates with natural law theorists and other varieties of legal positivism.

Scholars typically treat Kelsen as a representative of a neo‑Kantian, “scientific” legal positivism, distinct from both classical command theories and later sociological approaches. At the same time, his insistence on the moral neutrality of legal science, his account of the state as identical with the legal order, and his claim that international law may stand above state sovereignty have generated extensive discussion and criticism. Subsequent sections present these themes and the major lines of interpretation and contestation in an explicitly comparative and non‑partisan way.

2. Life and Historical Context

Kelsen’s life unfolded across the dramatic political transformations of Central Europe and the rise of global institutions in the twentieth century. Born in 1881 in Prague and raised in Vienna, he was educated in the late Austro‑Hungarian Empire, a multi‑ethnic monarchy whose constitutional and legal tensions formed an important backdrop to his lifelong concern with constitutional structure and supra‑national legal orders.

After earning his doctorate in law in Vienna (1906), Kelsen developed as a scholar during the high period of Viennese modernism and neo‑Kantian philosophy, when many intellectuals sought rigorous, “scientific” foundations for the humanities and social sciences. The collapse of the Habsburg Empire after World War I created both a crisis and an opportunity: in the newly formed Republic of Austria, Kelsen helped draft the 1920 Constitution and design its Constitutional Court, directly engaging with constitutional questions in a fragile, polarized democracy.

Authoritarian turns in Central Europe—first in Austria, then in Germany—shaped the next phase of his life. Dismissed from his Cologne chair in 1933 under the Nazi regime and later leaving Geneva after political pressure, Kelsen eventually emigrated to the United States, joining the University of California, Berkeley. His exile from fascism and observation of totalitarian legal practices informed his preoccupation with the rule of law, constitutional review, and the vulnerability of legal systems to political capture.

Kelsen’s later work on international law and world order developed against the background of the League of Nations, World War II, the Nuremberg Trials, and the early United Nations. These events provided both empirical material and a testing ground for his claims about the possibility of an overarching international legal order that could regulate state behavior and challenge traditional conceptions of absolute sovereignty.

3. Intellectual Development

Kelsen’s intellectual development is often divided into several phases that correspond to changing contexts and emphases, while retaining a core commitment to a norm‑centered, “pure” legal science.

Early Viennese, Neo‑Kantian Phase

In his Viennese years up to World War I, Kelsen was influenced by neo‑Kantian philosophy (especially the Marburg and South‑West German schools). He applied the distinction between “is” (Sein) and “ought” (Sollen) to legal theory, arguing that law must be understood as a system of norms, not as empirical facts. Hauptprobleme der Staatsrechtslehre (1911) already articulates key ideas: the identity of state and legal order, the hierarchy of norms, and the methodological separation of legal science from ethics and sociology.

Constitutional Architect and Early Pure Theory

During the interwar period in Austria and then Germany (roughly 1919–1933), Kelsen combined academic work with constitutional design. His experience drafting the 1920 Austrian Constitution and serving on the Constitutional Court reinforced his focus on constitutional norms as the apex of the national legal order. In this period he refined the Pure Theory of Law as a general framework, emphasizing value‑neutrality and a sharp boundary between legal validity and moral worth.

Exile, International Law, and Democracy

Forced into exile by authoritarian regimes, Kelsen worked in Geneva and later in the United States. From the 1930s through the 1940s he deepened his engagement with international law, war responsibility, and democratic theory, elaborating his procedural conception of democracy and a monist view in which international law could, in principle, stand above national legal systems.

Late Systematization

In his Berkeley years, Kelsen focused on systematizing and defending his earlier positions against critics. The second edition of Reine Rechtslehre (1960) reworked his account of the Grundnorm, clarified the structure of legal systems, and integrated his views on international law, presenting the mature version of his overall theoretical project.

4. Major Works and Projects

Kelsen’s writings span public law, general legal theory, democracy, and international law. Several works are commonly treated as landmarks within his broader project of a Pure Theory of Law.

Overview of Key Works

Beyond these books, Kelsen produced influential writings on constitutional courts, democratic theory (notably Vom Wesen und Wert der Demokratie), and the legal assessment of war, peace, and international responsibility. His practical involvement in drafting the 1920 Austrian Constitution and designing its Constitutional Court is often treated as a “project” in which his theoretical views on norm hierarchy and constitutional review took concrete institutional form.

5. Core Ideas: Pure Theory, Norms, and the Grundnorm

Kelsen’s Pure Theory of Law aims to describe and systematize positive law as a structure of norms, while excluding moral, political, psychological, and sociological considerations from legal science.

Law as a System of Norms

For Kelsen, a legal norm is the meaning of an act of will that prescribes a sanction under certain conditions (e.g., “If someone commits theft, they ought to be punished”). The legal order is a hierarchical system of such norms, where each lower‑level norm derives its validity (Geltung) from a higher‑level norm that authorizes its creation. This yields a Stufenbau (tiered structure) from individual administrative or judicial acts, through statutes, up to the constitution.

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“The pure theory of law is a theory of positive law… not of what the law ought to be, but of what the law is.”

— Hans Kelsen, Pure Theory of Law (1934)

Validity and the Basic Norm (Grundnorm)

Kelsen distinguishes legal validity from both efficacy (actual obedience) and moral correctness. A norm is valid if it has been created in the manner prescribed by a higher norm. To avoid an infinite regress, Kelsen introduces the Basic Norm (Grundnorm): a presupposed higher‑order norm such as “The constitution ought to be obeyed.”

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“The basic norm is the content of the presupposition that the Constitution ought to be obeyed.”

— Hans Kelsen, Pure Theory of Law (1960)

The Grundnorm is not enacted by any authority and is not a moral principle; it is a transcendental‑logical presupposition that allows jurists to regard the system of norms as a unitary legal order. Some interpreters emphasize its logical‑epistemic role in legal cognition; others treat it more as a hypothetical construct that summarizes the ultimate rule of recognition for a given system. Subsequent sections consider how this notion has been defended, reformulated, and criticized within jurisprudence.

6. Kelsen’s Methodology and Neo-Kantian Background

Kelsen’s methodology is shaped by neo‑Kantian philosophy, especially its emphasis on the distinction between facts and norms and the quest for “pure” sciences of specific domains.

Is/Ought and the Autonomy of Legal Science

Adapting Kantian themes, Kelsen insists that “is” (Sein) statements about social facts cannot logically entail “ought” (Sollen) statements about legal norms. Legal science should therefore concern itself with the normative meaning of legal acts, not with their psychological motives, sociological causes, or moral evaluation. This yields his notion of a “pure” theory: a methodological restriction that brackets extra‑legal value judgments.

Transcendental Structure of the Legal Order

Drawing on neo‑Kantian “transcendental” arguments, Kelsen presents the legal order as a set of conditions that make possible the cognition of law as a unified normative system. The Grundnorm functions analogously to a Kantian transcendental principle: not as an empirical or moral fact, but as a presupposition required to interpret acts of legislation, adjudication, and enforcement as legally valid.

Relation to Other Methodological Approaches

Kelsen contrasts his approach with:

Proponents of Kelsen’s methodology view it as providing a rigorously scientific jurisprudence; critics argue that the strict separation of law from morality and social facts is either untenable or artificially restrictive. Later sections address these debates in more detail.

7. Constitutional Theory and Democracy

Kelsen’s constitutional theory applies the Pure Theory’s concepts of norm hierarchy and validity to the structure of the state, while his democratic theory focuses on the procedures by which legal norms are created.

Hierarchy of Norms and Constitutional Review

For Kelsen, the constitution occupies the highest positive level in the national legal order, immediately beneath the presupposed Grundnorm. It authorizes the creation of general statutes, administrative acts, and judicial decisions. This hierarchical view underpins his support for centralized constitutional review, vested in a constitutional court empowered to annul statutes that conflict with constitutional norms.

His design for the Austrian Constitutional Court (1920) operationalized this idea: ordinary courts apply statutes, while the constitutional court checks their validity against the constitution. Proponents see this model as giving concrete institutional form to the norm hierarchy and protecting the supremacy of constitutional norms; critics have questioned its implications for parliamentary sovereignty and judicial power.

Procedural Conception of Democracy

Kelsen famously offers a procedural and relativist conception of democracy. Democracy, on his view, is the political form in which those subject to the legal order participate, directly or indirectly, in its creation:

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“One can define democracy as that form of government in which the creation of the legal order is determined by the will of those subject to it.”

— Hans Kelsen, On the Essence and Value of Democracy (1920)

He associates democracy with majority decision rules, pluralistic party competition, and protection of minority rights within the law‑making process. Rather than grounding democracy in substantive moral ideals, Kelsen links its value to epistemic humility and value pluralism: in a world of conflicting values, procedures that allow peaceful compromise and change are favored.

Some interpreters view this as a purely formal, value‑neutral defense of democracy; others argue that it presupposes substantive commitments to equality, freedom of opinion, and the rule of law, even if Kelsen presents these commitments in largely procedural terms.

8. International Law and World Legal Order

Kelsen devoted considerable effort to showing that international law is a genuine legal order and exploring its relation to national legal systems.

Monism and the Primacy Question

Kelsen advocates a monist view: international law and national law belong to a single normative system, rather than being fundamentally separate orders. Within this monism, he considers two possibilities: primacy of national law or primacy of international law. He ultimately develops a model in which international law can be treated as the higher‑level order that authorizes the existence and powers of states.

This leads to the idea that state sovereignty is relative: states are sovereign only within the limits set by international norms. Supporters argue that this helps make sense of binding treaties, war prohibitions, and international responsibility; critics maintain that, descriptively, states still control treaty adherence and that Kelsen’s model may over‑legalize political relations.

International Legal Order and Enforcement

In Principles of International Law (1952), Kelsen extends his norm‑hierarchical analysis to institutions such as the League of Nations, the United Nations, and international tribunals. He treats international sanctions—retorsions, reprisals, and collective security measures—as normatively structured reactions to violations, even if enforcement mechanisms are comparatively weak.

He also analyzes war as a legally regulated institution that international law could, in principle, prohibit or restrict. His writings on the Nuremberg Trials and individual responsibility for war crimes explore how international norms might directly bind individuals, not only states.

The following table highlights key contrasts Kelsen draws:

This framework has been influential in debates about global constitutionalism, though it has also faced sustained criticism from pluralist and realist perspectives.

9. Debates with Natural Law and Other Positivists

Kelsen’s positions emerged in dialogue and controversy with natural law theorists and other legal positivists, especially within the German‑speaking world and later in Anglophone jurisprudence.

Natural Law Theories

Natural law approaches typically hold that there are objective moral principles that ground valid law. Some proponents claim that a sufficiently unjust norm is not genuine law. Kelsen criticizes this on two fronts:

• Analytically, he argues that confusing validity with moral worth undermines the possibility of a value‑neutral legal science.
• Methodologically, he contends that appeals to “nature” or “reason” to justify specific moral contents are ultimately irrational or ideological.

Natural law advocates respond that Kelsen’s strict separation of law and morality makes it difficult to explain why legal norms should be obeyed, or to condemn grossly unjust enactments as legally defective rather than merely immoral.

Other Legal Positivists

Kelsen’s debates with other positivists center on the nature of norms, validity, and the foundations of legal systems.

Anglophone critics, including H. L. A. Hart and others, have questioned whether the Grundnorm is necessary or whether legal systems can instead be explained through social rules accepted by officials. Some German and Austrian scholars have argued that Kelsen’s normativism neglects the empirical dimensions of legal institutions.

Proponents of Kelsen’s view reply that his approach uniquely captures the normativity of law—its “ought” character—while many alternatives risk reducing law to patterns of behavior, coercion, or moral evaluation. Later sections consider how these debates shape his reception and influence.

10. Reception, Criticism, and Influence on Analytic Jurisprudence

Kelsen’s work has had a complex reception, combining strong influence with sustained criticism across different intellectual traditions.

Continental and Global Reception

In German‑speaking and Central European contexts, Kelsen’s Pure Theory ignited extensive debates on state theory, constitutional review, and the nature of legal science. Some constitutional courts (for example, in Austria and later in various civil‑law countries) have drawn, directly or indirectly, on his model of centralized review and norm hierarchy. In Latin America, Central and Eastern Europe, and parts of Asia, Kelsenian ideas have influenced discussions of constitutional supremacy and judicial control of legislation.

Critics in these contexts have often argued that his strict normativism underplays social power relations and material conditions, or that his formalism is ill‑suited to transformative constitutionalism and rights‑based adjudication.

Influence on Analytic Jurisprudence

In Anglophone analytic philosophy of law, Kelsen is best known for his account of normativity, validity, and the Grundnorm. His work has served as both a model and a foil for later theorists:

• H. L. A. Hart engages critically with Kelsen’s notion of a presupposed Basic Norm, proposing instead a rule of recognition grounded in social practices of officials.
• Other positivists and normativists have drawn on or challenged Kelsen’s attempt to explain how legal norms can be both socially enacted and normatively binding without invoking moral truths.

Debate has also focused on his separation of law and morality. Supporters see it as clarifying the descriptive task of jurisprudence; opponents argue that it either cannot be maintained in practice (given the role of moral reasoning in adjudication) or obscures important evaluative questions.

Overall, Kelsen’s framework has become a standard reference point in analytic discussions of legal systems, sources of law, and the conceptual relation between law, morality, and social facts, even among those who reject key elements of his theory.

11. Legacy and Historical Significance

Kelsen’s legacy is shaped by both his theoretical innovations and his impact on legal and political institutions.

Impact on Legal Theory and Philosophy

In jurisprudence, Kelsen is frequently cited as a central figure in modern legal positivism and normativism. His formal analysis of law as a hierarchical system of norms and his introduction of the Grundnorm have become canonical reference points in discussions of legal validity, system unity, and normativity. Subsequent theories—whether positivist, natural law, or interpretivist—often position themselves in relation to Kelsen’s attempts to separate legal analysis from moral evaluation.

His influence extends into political philosophy, particularly procedural theories of democracy and conceptions of the rule of law that stress the importance of norm‑governed, reviewable exercises of power. Some scholars regard his work as a paradigmatic expression of a liberal, pluralist response to the crises of the twentieth century; others view it as emblematic of technocratic legalism.

Institutional and International Significance

Institutionally, Kelsen’s role in designing the Austrian Constitutional Court helped inspire later models of centralized constitutional review, now common in many civil‑law systems. His writings on international law contributed to emerging debates about global governance, individual criminal responsibility, and limitations on sovereignty.

In the history of ideas, Kelsen is situated at the intersection of neo‑Kantian philosophy, Viennese modernism, and the post‑war development of analytic legal philosophy. His works continue to be reinterpreted: some recent scholarship emphasizes their systematic coherence; others stress tensions between his methodological purism and his normative commitments to democracy and constitutionalism.

Taken together, these strands have secured Kelsen a lasting place in discussions of what law is, how legal systems are structured, and how legal orders relate to politics, morality, and the international community.