Indifferenzkurven und Grenznutzenniveau

This file is a single-author theoretical journal article, originally published in 1954. Mahr intervenes in the German-Austrian controversy over Paretoan and Hicksian indifference-curve analysis and the related doctrine of a common marginal-utility level. He begins with Hans Mayer’s objections—fictive “experiment,” infinitesimal divisibility, and unlimited substitutability—then makes the critique his own: the theory’s supposed object, a field of equally valued consumption bundles, is not an empirical fact.

Die Annahme, daß es jeweils eine mehr oder minder große Zahl von Konsumkombinationen von Gütern gibt, die für das Individuum durchaus gleichwertig sind, beruht auf einer völligen Verkennung der Wirklichkeit.

English translation: The assumption that in each case there exists a more or less large number of consumption combinations of goods that are entirely equivalent for the individual rests on a complete misapprehension of reality.

His central thesis is that consumption goods combined in use normally have a determinate best proportion. Bread and wine, bread and butter, coffee and milk are not arbitrary substitutes along a smooth curve; they have preferred mixtures, which income and prices may prevent. What looks like indifference is often only constrained retreat from an ideal relation.

In Wahrheit gibt es regelmäßig nur ein optimales Kombinationsverhältnis zweier Konsumgüter.

English translation: In truth, there is regularly only one optimal combination ratio of two consumer goods.

Thus the familiar diagram contains only one reliable element: the budget line, as a representation of feasible purchases. Mahr replaces indifference curves with curves of preferred combinations under changing income or prices; expenditure rises toward an ideal mixture or saturation point, then additional income goes elsewhere. His anti-Paretian point is simple:

Gewiß gibt es zahllose Möglichkeiten in der Kombination der Verbrauchsgüter, und diese offenkundige Tatsache war der Ausgangspunkt für die Konstruktion der Indifferenzkurven. Aber diese Kombinationen sind in Wahrheit alles andere als indifferent.

English translation: Certainly, there are countless possibilities in the combination of consumer goods, and this obvious fact was the starting point for the construction of indifference curves. But in truth these combinations are anything but indifferent.

The empirical critique then widens. Demand for a good cannot be inferred from a two-good map, because goods enter many consumption contexts and may also be consumed alone. Consumers do not always execute a complete rational plan: habit, milieu, advertising, and episodic desire shape purchases. For durables such as cars, refrigerators, or radios, “indifferent combinations” with bread, potatoes, or soap become especially artificial.

The second half applies the same realism to the Grenznutzenniveau. Mahr’s decisive distinction is between broad need-classes such as food, clothing, and housing, and particular goods. General-equilibrium theory, he argues, falsely identifies the utility curve of a commodity with the intensity curve of the need it serves. Rising income does not mean ever more of the same goods; beyond a point quantitative extension yields to qualitative differentiation.

Die „fortgesetzte“ Befriedigung eines Bedürfnisses besteht dann nicht mehr darin, daß noch mehr Einheiten des zunächst verwendeten Gutes konsumiert werden, sondern Güter anderer Art oder Qualität.

English translation: The "continued" satisfaction of a want then no longer consists in consuming still more units of the good originally employed, but rather goods of another kind or quality.

Mahr therefore narrows Gossen’s second law. A tendency toward equal marginal significance may hold across broad purposes, especially at very low incomes where necessities themselves are marginal. But for higher incomes many necessities lie in an “over-marginal” zone: a small price increase in bread or potatoes will not reduce demand, so their marginal utility exceeds that of money.

Soweit es berechtigt ist, von einem Grenznutzenniveau zu sprechen, findet dieses seinen deutlichsten Ausdruck in dem Grenznutzen des Geldes.

English translation: Insofar as it is justified to speak of a marginal utility level, this finds its clearest expression in the marginal utility of money.

This frame explains his objections to Jöhr and Krelle. Their formal defenses of universal equalization confuse need-classes with individual goods; Krelle’s salt example, in Mahr’s view, infers utility shifts from price shifts in order to rescue the theorem. That reverses explanation:

Der Nutzen wird so aus einem Preisbestimmungsgrund zu einem Ergebnis der Preisbildung.

English translation: Utility thus becomes, from a determinant of price, a result of price formation.

The article’s relevance lies in its alternative to both cardinal utility calculation and ordinal indifference formalism. Mahr does not abandon marginal utility; he relocates it within ranked needs, preferred combinations, income constraints, saturation, quality change, and observable behavior. His final methodological warning is that mathematics can aid economics only when preceded by exact observation of the psychological and practical facts of valuation.