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Part One: The Nature of Money > Chapter 2. On the Measurement of Value

3. Money as a Price-Index

What has been said should have made sufficiently plain the unscientific nature of the practice of attributing to money the function of acting as a measure of price or even of value. Subjective value is not measured, but graded. The problem of the measurement of objective use-value is not an economic problem at all. (It may incidentally be remarked that a measurement of efficiency is not possible for every species of commodity and is at the best only available within separate species, while every possibility, not only of measurement, but even of mere scaled comparison, vanishes as soon as we seek to establish a relation between two or more kinds of efficiency. It may be possible to measure and compare the calorific value of coal and of wood, but it is in no way possible to reduce to a common objective denominator the objective efficiency of a table and that of a book.)

Neither is objective exchange value measurable, for it too is the result of the comparisons derived from the valuations of individuals. The objective exchange value of a given commodity unit may be expressed in units of every other kind of commodity. Nowadays exchange is usually carried on by means of money, and since every commodity has therefore a price expressible in money, the exchange value of every commodity can be expressed in terms of money. This possibility enabled money to become a medium for expressing values when the growing elaboration of the scale of values which resulted from the development of exchange necessitated a revision of the technique of valuation.

That is to say, opportunities for exchanging induce the individual to rearrange his scales of values. A person in whose scale of values the commodity "a cask of wine" comes after the commodity "a sack of oats" will reverse their order if he can exchange a cask of wine in the market for a commodity that he values more highly than a sack of oats. The position of commodities in the value scales of individuals is no longer determined solely by their own subjective use-value, but also by the subjective use-value of the commodities that can be obtained in exchange for them, whenever the latter stand higher than the former in the estimation of the individual. Therefore, if he is to obtain the maximum utility from his resources, the individual must familiarize himself with all the prices in the market.

For this, however, he needs some help in finding his way among the confusing multiplicity of the exchange ratios. Money, the common medium of exchange, which can be exchanged for every commodity and with which every commodity can be procured, is preeminently suitable for this. It would be absolutely impossible for the individual, even if he were a complete expert in commercial matters, to follow every change of market conditions and make the corresponding alterations in his scale of use-values and exchange values, unless he chose some common denominator to which he could reduce each exchange ratio. Because the market enables any commodity to be turned into money and money into any commodity, objective exchange value is expressed in terms of money. Thus money becomes a price index, in Menger's phrase. The whole structure of the calculations of the entrepreneur and the consumer rests on the process of valuing commodities in money. Money has thus become an aid that the human mind is no longer able to dispense with in making economic calculations.9 If in this sense we wish to attribute to money the function of being a measure of prices, there is no reason why we should not do so. Nevertheless, it is better to avoid the use of a term which might so easily be misunderstood as this. In any case the usage certainly cannot be called correct—we do not usually describe the determination of latitude and longitude as a "function" of the stars.10

  • 9. On the indispensability of money for economic calculation, see my book Die Gemeinwirtschaft: Untersuchungen über den Sozialismus(Jena, 1922), pp. 100 ff.
  • 10. [This chapter deals with technical matters which may present difficulty to readers unacquainted with general economic theory. It may be omitted on a first reading, but it is essential to complete understanding of certain issues, such as the index-number problem, which are dealt with later.—Editor.]