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## 2. The Nature of the Problem

The objective exchange value of the monetary unit can be expressed in units of any individual commodity. Just as we are in the habit of speaking of a money price of the other exchangeable goods, so we may conversely speak of the commodity price of money, and have then so many expressions for the objective exchange value of money as there are commercial commodities that are exchanged for money. But these expressions tell us little; they leave unanswered the questions that we want to solve. There are two parts to the problem of measuring the objective exchange value of money. First we have to obtain numerical demonstration of the fact of variations in the objective exchange value of money; then the question must be decided whether it is possible to make a quantitative examination of the causes of particular price movements, with special reference to the question whether it would be possible to produce evidence of such variations in the purchasing power of money as lie on the monetary side of the ratio1

So far as the first-named problem is concerned, it is self-evident that its solution must assume the existence of a good, or complex of goods, of unchanging objective exchange value. The fact that such goods are inconceivable needs no further elucidation. For a good of this sort could exist only if all the exchange ratios between all goods were entirely free from variations. With the continually varying foundations on which the exchange ratios of the market ultimately rest, this presumption can never be true of a social order based upon the free exchange of goods.2

To measure is to determine the ratio of one quantity to another which is invariable or assumed to be invariable. Invariability in respect of the property to be measured, or at least the legitimacy of assuming such invariability, is a sine qua non of all measurement. Only when this assumption is admissible is it possible to determine the variations that are to be measured. Then, if the ratio between the measure and the object to be measured alter, this can only be referred to causes directly affecting the latter. Thus the problems of measuring the two kinds of variation in the objective exchange value of money go together. If the one is proved to be soluble, then so also is the other; and proof of the insolubility of the one is also proof of the insolubility of the other.

• 1. [Following Menger, we should call the first of these two problems the problem of the measurability of the äussere objective exchange value of money, the second that of the measurability of its innere objective exchange value. See also p. 146 n. H.E.B.]
• 2. See Menger, Grundsätze der Volkswirtschaftslehre, 2d ed. (Vienna, 1923), pp. 298 ff.  