Felix Kaufmann, “The Pure Theory of Law. By William Ebenstein.” (October 1945)

Felix Kaufmann’s book review assesses William Ebenstein’s introduction to Hans Kelsen’s Pure Theory of Law as both an exposition of legal methodology and an intervention in its reception among English-speaking readers. Its movement is compact: Kaufmann establishes the theory’s broader importance, explains its methodological distinctions and account of legal unity, describes Ebenstein’s presentation, and concludes by proposing a revision of its philosophical foundations. His judgment combines strong approval of the book with disagreement over a premise that Ebenstein largely leaves unquestioned.

Kaufmann recommends Ebenstein’s study beyond the audience of professional jurists. The Pure Theory concerns the logical foundations of legal science, but its attempt to distinguish kinds of knowledge also makes it important to social and political philosophy. Kaufmann contrasts extensive debate about Kelsen’s work with its comparatively limited recognition in the United States and Great Britain. Against the claim that the theory belongs exclusively to “Continental logical thinking” and cannot illuminate Common Law, Ebenstein identifies comparable problems and solutions among American and British jurists. Kelsen’s distinctive contribution, on this account, is the systematic organization of questions that cross legal traditions.

The review locates the theory’s organizing commitment in methodological separation:

The postulate of purity of method, which is its guiding principle, demands a sharp distinction between juristic methods and psychological as well as sociological methods, and between legal norms and ethical norms.

Purity here concerns the identity of legal inquiry. Psychology and sociology explain through causal relations, whereas legal science studies norms; Kaufmann presents this distinction through the opposition between the Is and the Ought. A second boundary separates legal science from ethics: positive law is the former’s subject, while natural law belongs to the latter. These distinctions establish what legal science investigates and how its explanations differ from accounts of conduct or judgments of moral rightness.

Kelsen’s analysis then asks what makes heterogeneous norms parts of one legal order. Statutes, judicial decisions, and executive orders differ in form and institutional origin, yet legal science must explain their unity.

Kelsen calls this principle "basic norm" (Grundnorm) and interprets it as a fundamental hypothesis comparable to the most general principles of the natural sciences.

The basic norm thus answers a question about the coherence of an order, rather than merely identifying another rule within it. Kaufmann reports that Ebenstein develops the theory in five chapters, beginning with its Neo-Kantian philosophical basis and proceeding through the position of legal science among other disciplines, the analysis of legal norms, and the hierarchical relations among their types. The “steps and stairs” theory supplies an account of those relations. Kaufmann praises the exposition’s competence while emphasizing that Ebenstein chiefly defends Kelsen; his criticisms address minor points rather than the theory’s foundational dualism.

The review’s decisive reservation concerns that separation of Is and Ought. Kaufmann recalls his own argument that the dualism cannot be sustained and proposes an alternative interpretation:

The normative method is taken to be simply a subsumption under given definitions, and a basic norm is conceived as a definition of the unity of a particular legal order.

This move recasts the basic norm from a fundamental hypothesis into a definition specifying what constitutes a particular legal order’s unity. Normative inquiry correspondingly becomes an operation under definitions, rather than a method grounded in the disputed dualism. Kaufmann does not develop the full argument for this revision in the review. Its significance lies in his claim that Kelsen’s chief methodological results survive it: one can question the philosophical foundation while retaining the theory’s clarification of legal science. The closing assessment therefore distinguishes Ebenstein’s valuable exposition, Kelsen’s enduring methodological achievements, and the reviewer’s proposed reconstruction of their basis.