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11. Money and Its Purchasing Power > 5. The Demand for Money

E. The PPM and the Rate of Interest

We have been discussing money, and shall continue to do so in the current section, by comparing equilibrium positions, and not yet by tracing step by step how the change from one position to another comes about. We shall soon see that in the case of the price of money, as contrasted with all other prices, the very path toward equilibrium necessarily introduces changes that will change the equilibrium point. This will have important theoretical consequences. We may still talk, however, as if money is “neutral,” i.e., does not lead to such changes, because this assumption is perfectly competent to deal with the problems analyzed so far. This is true, in essence, because we are able to use a general concept of the “purchasing power of money” without trying to define it concretely in terms of specific arrays of goods. Since the concept of the PPM is relevant and important even though its specific content changes and cannot be measured, we are justified in assuming that money is neutral as long as we do not need a more precise concept of the PPM.

We have seen how changes in the money relation change the PPM. In the determination of the interest rate, we must now modify our earlier discussion in chapter 6 to take account of allocating one's money stock by adding to or subtracting from one's cash balance. A man may allocate his money to consumption, investment, or addition to his cash balance. His time preferences govern the proportion which an individual devotes to present and to future goods, i.e., to consumption and to investment. Now suppose a man's demand-for-money schedule increases, and he therefore decides to allocate a proportion of his money income to increasing his cash balance. There is no reason to suppose that this increase affects the consumption/investment proportion at all. It could, but if so, it would mean a change in his time preference schedule as well as in his demand for money.

If the demand for money increases, there is no reason why a change in the demand for money should affect the interest rate one iota. There is no necessity at all for an increase in the demand for money to raise the interest rate, or a decline to lower it—no more than the opposite. In fact, there is no causal connection between the two; one is determined by the valuations for money, and the other by valuations for time preference.

Let us return to the section in chapter 6 on Time Preference and the Individual's Money Stock. Did we not see there that an increase in an individual's money stock lowers the effective time-preference rate along the time-preference schedule, and conversely that a decrease raises the time-preference rate? Why does this not apply here? Simply because we were dealing with each individual's money stock and assuming that the “real” exchange-value of each unit of money remained the same. His time-preference schedule relates to “real” monetary units, not simply to money itself. If the social stock of money changes or if the demand for money changes, the objective exchange-value of a monetary unit (the PPM) will change also. If the PPM falls, then more money in the hands of an individual may not necessarily lower the time-preference rate on his schedule, for the more money may only just compensate him for the fall in the PPM, and his “real money stock” may therefore be the same as before. This again demonstrates that the money relation is neutral to time preference and the pure rate of interest.

An increased demand for money, then, tends to lower prices all around without changing time preference or the pure rate of interest Thus, suppose total social income is 100, with 70 allocated to investment and 30 to consumption. The demand for money increases, so that people decide to hoard a total of 20. Expenditure will now be 80 instead of 100, 20 being added to cash balances. Income in the next period will be only 80, since expenditures in one period result in the identical income to be allocated to the next period.9 If time preferences remain the same, then the proportion of investment to consumption in the society will remain roughly the same, i.e., 56 invested and 24 consumed. Prices and nominal money values and incomes fall all along the line, and we are left with the same capital structure, the same real income, the same interest rate, etc. The only things that have changed are nominal prices, which have fallen, and the proportion of total cash balances to money income, which has increased.

A decreased demand for money will have the reverse effect. Dishoarding will raise expenditure, raise prices, and, ceteris paribus, maintain the real income and capital structure intact. The only other change is a lower proportion of cash balances to money income.

The only necessary result, then, of a change in the demand-for-money schedule is precisely a change in the same direction of the proportion of total cash balances to total money income and in the real value of cash balances. Given the stock of money, an increased scramble for cash will simply lower money incomes until the desired increase in real cash balances has been attained.

If the demand for money falls, the reverse movement occurs. The desire to reduce cash balances causes an increase in money income. Total cash remains the same, but its proportion to incomes, as well as its real value, declines.10

  • 9. Since no one can receive a money income unless someone else makes a money expenditure on his services. (See chapter 3 above.)
  • 10. Strictly, the ceteris paribus condition will tend to be violated. An increased demand for money tends to lower money prices and will therefore lower money costs of gold mining. This will stimulate gold mining production until the interest return on mining is again the same as in other industries. Thus, the increased demand for money will also call forth new money to meet the demand. A decreased demand for money will raise money costs of gold mining and at least lower the rate of new production. It will not actually decrease the total money stock unless the new production rate falls below the wear-and-tear rate. Cf. Jacques Rueff, “The Fallacies of Lord Keynes’ General Theory” in Henry Hazlitt, ed., The Critics of Keynesian Economics (Princeton, N.J.: D. Van Nostrand, 1960), pp. 238–63.