A. Money in the ERE and in the Market

It is true, as we have said, that the only use for money is in exchange. From this, however, it must not be inferred, as some writers have done, that this exchange must be immediate. Indeed, the reason that a reservation demand for money exists and cash balances are kept is that the individual is keeping his money in reserve for future exchanges. That is the function of a cash balance—to wait for a propitious time to make an exchange.

Suppose the ERE has been established. In such a world of certainty, there would be no risk of loss in investment and no need to keep cash balances on hand in case an emergency for consumer spending should arise. Everyone would therefore allocate his money stock fully, to the purchase of either present goods or future goods, in accordance with his time preferences. No one would keep his money idle in a cash balance. Knowing that he will want to spend a certain amount of money on consumption in six months’ time, a man will lend his money out for that period to be returned at precisely the time it is to be spent. But if no one is willing to keep a cash balance longer than instantaneously, there will be no money held and no use for a money stock. Money, in short, would either be useless or very nearly so in the world of certainty.

In the real world of uncertainty, as contrasted to the ERE, even “idle” money kept in a cash balance performs a use for its owner. Indeed, if it did not perform such a use, it would not be kept in his cash balance. Its uses are based precisely on the fact that the individual is not certain on what he will spend his money or of the precise time that he will spend it in the future.

Economists have attempted mechanically to reduce the demand for money to various sources.7 There is no such mechanical determination, however. Each individual decides for himself by his own standards his whole demand for cash balances, and we can only trace various influences which different catallactic events may have had on demand.

• 7J.M. Keynes’ Treatise on Money (New York: Harcourt, Brace, 1930) is a classic example of this type of analysis.