The Theory of Money and Credit - Ludwig von Mises [56]
If the objective exchange value of money must always be linked with a preexisting market exchange ratio between money and other economic goods (since otherwise individuals would not be in a position to estimate the value of the money), it follows that an object cannot be used as money unless, at the moment when its use as money begins, it already possesses an objective exchange value based on some other use. This provides both a refutation of those theories which derive the origin of money from a general agreement to impute fictitious value to things intrinsically valueless[4] and a confirmation of Menger's hypothesis concerning the origin of the use of money.
This link with a preexisting exchange value is necessary not only for commodity money, but equally for credit money and fiat money. [5] No fiat money could ever come into existence if it did not satisfy this condition. Let us suppose that, among those ancient and modern kinds of money about which it may be doubtful whether they should be reckoned as credit money or fiat money, there have actually been representatives of pure fiat money. Such money must have come into existence in one of two ways. It may have come into existence because money substitutes already in circulation, that is, claims payable in money on demand, were deprived of their character as claims, and yet still used in commerce as media of exchange. In this case, the starting point for their valuation lay in the objective exchange value that they had at the moment when they were deprived of their character as claims. The other possible case is that in which coins that once circulated as commodity money are transformed into fiat money by cessation of free coinage (either because there was no further minting at all or because minting was continued only on behalf of the Treasury), no obligation of conversion being de jure or de facto assumed by anybody, and nobody having any grounds for hoping that such an obligation ever would be assumed by anybody. Here the starting point for the valuation lies in the objective exchange value of the coins at the time of the cessation of free coinage.
Before an economic good begins to function as money it must already possess exchange value based on some other cause than its monetary function. But money that already functions as such may remain valuable even when the original source of its exchange value has ceased to exist. Its value then is based entirely on its function as common medium of exchange. [6]
3 The Significance of Preexisting Prices in the Determination of Market Exchange Ratios
From what has just been said, the important conclusion follows that a historically continuous component is contained in the objective exchange value of money.
The past value of money is taken over by the present and transformed by it; the present value of money passes on into the future and is transformed in its turn. In this there is a contrast between the determination of the exchange value of money and that of the exchange value of other economic goods. All preexisting exchange ratios are quite irrelevant so far as the actual levels of the reciprocal exchange ratios of other economic goods are concerned. It is true that if we look beneath the concealing monetary veil to the real exchange ratios between goods we observe a certain continuity. Alterations in real prices occur slowly as a rule. But this stability of prices has its cause in the stability of the price determinants, not in the law of price determination itself. Prices change slowly because the subjective valuations of human beings change slowly. Human needs, and human opinions as to the suitability of goods for satisfying those needs, are no more liable to frequent and sudden changes than are the stocks of goods available for consumption, or the manner of their social distribution. The fact that today's market price is seldom very different from yesterday's is to be explained by the fact that the circumstances that determined yesterday's price have not greatly changed