Eugen von Böhm-Bawerk, “Woran eine richtige Zinstheorie …” (1899)

This file is a single-author theoretical polemic in German: Böhm-Bawerk uses four numbered sections to define the proper test of an interest theory and to answer Philippovich, Dietzel, and Lexis. Its central thesis is methodological: a correct theory of capital interest must explain only genuine interest, but it must explain all genuine interest under one coherent causal account.

Insbesondere also nicht solche Einnahmen oder Einkünfte, die zwar äusserlich mit einem Capitalzins oder einer Capitalrente zusammengemischt, aber innerlich von einer anderen Wesenheit sind.

English translation: In particular, then, not those receipts or revenues which are outwardly mixed together with a capital interest or a capital rent, but are inwardly of a different essence.

This opening distinction governs the whole essay. Risk premiums, amortization, personal effort, entrepreneurial talent, and monopoly gains may be mingled with “Bruttozins,” but they are not capital interest. Böhm-Bawerk therefore criticizes Philippovich for reintroducing entrepreneurial scarcity into the explanation of “Capitalgewinn.” If rare entrepreneurial ability raises income, the increment belongs to Unternehmergewinn, not to the return imputable to capital as such; the same logic would otherwise confuse ground rent with managerial ability.

Against Dietzel, Böhm-Bawerk rejects explanatory eclecticism. Dietzel’s proposal that productivity theory, use theory, exploitation theory, and Böhm-Bawerk’s own present-goods theory each apply to different interest cases appears to him as a category mistake. Scientific classes must rest on inner kinship, not surface resemblance.

Unterarten müssen naturgemäß das Wesen der Art haben.

English translation: Subspecies must, by their very nature, share the essence of the species.

Thus different forms of interest may have special features, but their explanation must share a common core. Otherwise “interest” becomes an empty label. Böhm-Bawerk’s polemic is sharpest where he insists that rival theories cannot be combined at will: productivity theory and exploitation theory rest on contradictory premises about whether capital itself contributes product. A theory that fails for one genuine class of interest is not a partial truth but an inadequate solution.

The third section turns the same test back on Böhm-Bawerk’s own theory. Philippovich had objected that trade capital and technical improvements can yield interest without lengthening production. Böhm-Bawerk replies that interest is not required to originate locally in every single transaction; it is a social resultant of the general premium on present over future goods.

Der Zins ist nun, wie ich in meiner „Positiven Theorie“ eingehend auseinandergesetzt habe, eine solche große sociale Resultante.

English translation: Interest is, as I have set forth in detail in my "Positive Theory," such a great social resultant.

His Nile analogy supports this move: a flood downstream need not be caused by rain falling at that exact place. Likewise, once the market premium on present goods is established through the general structure of production and time, it governs commercial and technical cases wherever present outlays are exchanged for future returns. If an enterprise formerly earned no interest, that proves not a special “interestless” case but entrepreneurial error or loss.

The final section attacks Lexis’s softened exploitation account as a “vulgär-ökonomischer” offshoot of socialist theory. Böhm-Bawerk grants that workers’ dependence is real and may cause wage oppression, but he denies that this by itself explains normal capital interest under competition. What is missing is not sympathy but causal articulation.

Sprechen wir es sofort aus: was die Zinstheorie bietet, muss eine wirkliche Erklärung des Zinsphänomenes, eine in sich zusammenhängende, lückenlose Darlegung seiner Ursachen sein.

English translation: Let us state it at once: what the theory of interest must offer must be a real explanation of the phenomenon of interest, a coherent, gapless exposition of its causes.

Without Marx’s labor-value theory, the exploitation argument loses its middle terms; it becomes, for Böhm-Bawerk, an assertion rather than a theory. He reads its growing appeal as part of an intellectual fashion.

Wir haben heute eine anticapitalistische Mode; das lässt sich meines Erachtens nicht mehr leugnen.

English translation: Today we have an anti-capitalist fashion; that, in my view, can no longer be denied.

The essay’s relevance lies in this double demand: conceptual purity and explanatory unity. Böhm-Bawerk separates theoretical diagnosis from social sympathy, warning that reformist motives cannot substitute for causal proof.

Von allem anderen abgesehen, halte ich es für einen der gefährlichsten methodischen Fehler des Theoretikers, wenn er Tendenzen in die Theorie trägt.

English translation: Setting all else aside, I consider it one of the most dangerous methodological errors of the theorist when he imports tendencies into theory.