The archive.

A jurisprudence resting solely on the ground of logic — that is the ambition of Kaufmann's outline of a "pure theory of law," which takes Kelsen's reine Rechtslehre and grounds it in Husserl's phenomenology of essence, against every empiricism that dissolves validity into fact. Jurisprudence becomes exact, he insists, only when it stops deriving its concepts from psychology, power, purpose, or moral value. A norm is not an imperative bound to a commander's will but an objectivation of a stance; the legal proposition is a double norm — a subject ought to act, and if it does not, a consequence ought to follow toward that subject — whose juristic core is formal imputation, not causality. From four ground concepts — person, behavior, fact, and ought — he generates the pure legal concepts, recasting the subjective right as nothing but the correlate of another's duty.

Jede theoretische Wissenschaft ist ein Inbegriff synthetischer Urteile a priori.

English translation: “Every theoretical science is a totality of synthetic a priori judgments.”

Does a stronger need explain an economic choice, or do we call the need stronger because that choice was made? This tension gives Felix Kaufmann’s 1923 study its critical edge. Drawing on Husserl’s distinction between material and formal concepts, Kaufmann asks what makes conduct economic, rather than what circumstances cause it. He challenges definitions grounded in scarcity or ranked purposes and treats marginal utility as a useful guide to empirical inquiry, not an independent psychological explanation. His alternative centres on behaviour that establishes an order of selection among goods, understood as relations to external things. The discussion of money sharpens the stakes: ranking goods does not yet mean measuring their values. Readers can discover where apparently explanatory economic concepts may merely redescribe the conduct they are meant to explain.

Legal concepts, Kaufmann argues, become intelligible only once the pure formal structure of law is stripped of everything empirical, psychological, sociological, and political clinging to it. Extending his earlier Logik und Rechtswissenschaft, this German study grounds jurisprudence in a general logic of science: the dualism of factual and essential knowledge, and a principle of compatibility spheres governing which predicates may belong to which domains. Against theories that define law by force, recognition, or fear of sanctions, Kaufmann insists that law is a totality of sanctioned norms, a double norm binding conduct to consequence, and that the juridical person is no metaphysical substance but a rule-governed unit of imputation. Fusing Husserlian phenomenology with Kelsen's pure theory, he traces legal validity to the Grundnorm and rejects natural law, since value-judgments admit no theoretical proof.

Recht ist ein Inbegriff sanktionierter Normen über menschliches Verhalten.

English translation: “Law is a totality of sanctioned norms concerning human conduct.”

If a preference is inferred from an exchange, can that same preference explain why the exchange occurred? Felix Kaufmann’s 1925 article makes such circularities central to its examination of economic theory. He distinguishes the concepts that define economic activity from the evidence needed to explain it, bringing an analysis of intentional action to bear on Austrian marginal utility theory. For Kaufmann, rankings of intended uses can guide inquiry, but cannot become necessary truths merely because they make choices intelligible. His scrutiny of economic measurement likewise locates substantive knowledge in the assumptions behind equations, not simply in their solution. The result offers a concrete way to distinguish what an economic model defines, what it assumes, and what it actually explains—without asking logic to replace empirical research.

Just as the nineteenth century banished infinitesimals from analysis without destroying the calculus, Kaufmann proposes to eliminate the actual infinite, above all Cantor's uncountable, without dismantling classical mathematics. First published in 1930 and reissued here in 1968, this German study locates the root of foundational paradox in a single confusion: the failure to distinguish empirical from non-empirical claims about all objects and their existence. Set-theoretic totalities, on his reading, are an ontological surplus smuggled in through misread symbolism, not objects the mind discovers. He preserves the finite core of the diagonal argument while denying that it defines a totality of all decimals, invokes the Löwenheim-Skolem theorem to argue that axiomatic set theory cannot isolate a genuinely uncountable domain, and reads Hilbert's ideal elements and Brouwer's constructivism as each carrying only part of the truth.

Ein „sinnloses Zeichen“ ist eine contradictio in adjecto, denn in der Behauptung, daß visuelle oder akustische Phänomene „Zeichen“ sind, liegt diejenige eingeschlossen, daß man durch sie etwas verstehen, mit ihrer Hilfe fremde Gedanken erfassen kann.

English translation: “A "meaningless sign" is a contradictio in adjecto, for the assertion that visual or acoustic phenomena are "signs" already contains the assertion that through them one can understand something, that with their help one can grasp the thoughts of others.”

When formalism, intuitionism, and logicism each stake a claim to the foundations of mathematics, the deeper trouble, Kaufmann contends, is one of sense: symbolic forms, abstractions, and abbreviations get mistaken for independent objects. This 1931 essay reworks the received theory of abstraction, recasting it not as the stripping-away of features but as the holding-fixed of an invariant structure while others vary, and turns it against conceptual realism and extensional logic alike. Expressions like properties of properties and functions of functions are legitimate only as translatable abbreviations. Natural number, on this account, is neither a class of equinumerous classes nor a property of collections but an abstraction from the ordered act of counting; Peano's axioms define that structure, and complete induction merely excludes further determinations. Undecidability, where it appears, signals not metaphysical depth but presuppositions that have failed to fix their object.

The central problem in the theory of a science lies in clearly grasping the sense of the relevant propositions.

Calculus can locate a monopolist’s maximum profit—but who establishes the demand and cost functions on which the calculation depends? In this 1931 article, Felix Kaufmann uses that distinction to reconsider what mathematics contributes to economics. His perspective joins the logical analysis of mathematical proof to an insistence on understanding economic motives: neither formal deduction nor price curves alone supply an empirical theory of action. Against both blanket objections to mathematization and overconfident analogies with physics, he asks when simplifying assumptions make inquiry productive and when they merely make calculation possible. Readers gain a precise way to distinguish computational success from economic discovery, and to examine what assumptions about continuity, measurement, and choice permit a model to explain.

The Methodenstreit had hardened into a war of slogans, naturalism against Verstehen, nomothetic against idiographic, value-free against normative, and this 1936 German treatise sets out to disarm every one of them. Kaufmann offers not a doctrine but a critique of principles: methods earn their place by problem-type and research aim, never by metaphysical prestige. Physical objectivity itself rests on schemas and measurement; social science differs because its objects include alter egos, projects, and socially available meanings, so understanding is indispensable yet never sovereign. Drawing on Weber and Schütz for controlled interpretation, he recasts marginal utility theory as an analysis of purpose-rational choice within a ranked goal-order, treats ideal types as instruments of causal control, and credits Kelsen with purifying legal dogmatics while rejecting the Sein/Sollen dualism. Plurality is preserved; its inflation into pseudo-conflict is what must go.

Demgemäß ist alle Kritik in diesem Buche Prinzipienkritik.

English translation: “Accordingly, all criticism in this book is criticism of principles.”

Understanding an action is not the same as establishing that one’s interpretation is correct. In this article, Felix Kaufmann makes that distinction central to a social science that neither imitates physics wholesale nor claims exemption from empirical testing. His example of a naval distress signal shows how deciphering words, recognizing a request, explaining an emergency, and inferring the sender’s knowledge require different evidence. Drawing on Weber and Schütz, he replaces sweeping disputes over scientific method with precise questions about what investigators assume and how their claims can be checked. Readers can discover why uncertainty need not mean vagueness, and why practical interests may shape the choice of a research problem without deciding what counts as an adequate answer.

Kaufmann relocates the objectivity of social science from private conviction to public procedure: a proposition is valid only relative to the rules that govern how claims are accepted, rejected, connected, and corrected within inquiry. Written in English under the influence of Dewey's Logic, the book refuses to seek certainty before science begins, holding that every attempt to ground empirical knowledge in self-evident truths is foredoomed. Its recurring operation is a sorting of levels, separating facts, meanings, rules of procedure, and formal relations that disputants habitually let slide into one another. Economic theory supplies his sharpest cases. Demand curves and marginal-utility principles are not empirical laws falsifiable by a single instance but theoretical rules; and Mises's a priori derivation of value and price is shown to be analytic unless tied to empirical rules. Objectivity here is procedural, not absolute; formalism clarifies rather than reduces.

All attempts to base empirical science on ultimate grounds conceived as self-evident truths are foredoomed to failure.

A prediction can come true without having been justified when it was made. This distinction anchors Felix Kaufmann’s inquiry into what makes a scientific judgment warranted when every empirical claim remains revisable. In this 1945 article, he uses analogies with law and grammar to locate scientific correctness in procedural standards rather than guaranteed truth or eventual success. Yet rules themselves change, and observation is never free of interpretation. Examples drawn from relativity and the failed Harvard business-cycle barometer give these tensions concrete form. Readers can discover how Kaufmann defends objectivity without claiming an ultimate foundation for scientific method—and why, for him, distinguishing warranted belief from fortunate conjecture matters to social inquiry and honest public argument.

Do scientists really inhabit an ivory tower, indifferent to a world their theories now visibly reshape? Kaufmann takes the postwar reproach seriously, made newly awkward by the political engagement of atomic physicists, and sorts it into four charges: impractical topics, excessive abstraction, inaccessible prose, and refusal to judge values. Practical value, he answers, is often indirect: Maxwell's electromagnetism and Einstein's mass-energy formula were merely theoretical before they proved decisive. Abstraction he splits into generalization, idealization, and mediate construction, defending each while insisting on the return to concrete phenomena. On Weber's ethical neutrality he grants that science cannot fix ultimate values, yet argues that value judgments are elliptical only until their standards are named. The essay's closing defense is of veracity itself, the philosopher's task of keeping disagreement clear and discussable, even at the cost of the tower.

To foster the spirit of veracity is the foremost educational task of the philosopher. Should the fulfilment of this task relegate him to the ivory tower, then he need not be ashamed of his abode.