But the problem for monetary theory is that without a real-value equivalent to assign to money, the value of money in our macroeconomic models became theoretically indeterminate. If the value of money is theoretically indeterminate, so, too, is the rate of inflation. The value of money and the rate of inflation are simply, as Fischer Black understood, whatever people in the aggregate expect them to be. Nevertheless, our basic mental processes for understanding how central banks can use an interest-rate instrument to control the value of money are carryovers from an earlier epoch when the value of money was determined, most of the time and in most places, by convertibility, either actual or expected, into gold or silver. The interest-rate instrument of central banks was not primarily designed as a method for controlling the value of money; it was the mechanism by which the central bank could control the amount of reserves on its balance sheet and the amount of gold or silver in its vaults. There was only an indirect connection – at least until the 1920s — between a central bank setting its interest-rate instrument to control its balance sheet and the effect on prices and inflation. The rules of monetary policy developed under a gold standard are not necessarily applicable to an economic system in which the value of money is fundamentally indeterminate.
Viewed from this perspective, the Neo-Fisherian Revolution appears as a kind of reductio ad absurdum of the present confused state of monetary theory in which the price level and the rate of inflation are entirely subjective and determined totally by expectations.