Metzler on Classical Interest Theory: Reply
回应梅尔·科恩对作者之前重构梅茨勒模型的批评，论证在古典假设下，货币中性且价格水平不确定，即使改变央行政策工具也无法改变这一结论。
Lloyd Metzler's Wealth, Saving, and the Rate of Interest has played a useful role in the development of monetary theory. Perhaps most importantly, it has stimulated significant contributions to our understanding of the nature of the classical general equilibrium. Among these contributions are two that I had thought were widely accepted: (i) in order for money prices to be determined they must impinge on some quantity or quantities that are fixed in nominal (money) terms (i.e., money prices must in a sense); and (ii) there is no real balance effect and money is neutral in all-insidemoney, equilibrium systems. Substantial portions of Don Patinkin's Money, Interest, and Prices are devoted to proofs and examples of these propositions.' It is no criticism of Metzler to point out that his seminal work failed to contain all of the refinements and corrections that it inspired. Less understandable has been the failure of several writers to apply the contributions of Patinkin and others to Metzler's representation of the classical framework, with the consequence that we have been exposed to repeated demonstrations of nonclassical results from a so-called classical model. purposes of my earlier paper were to bring Metzler's much used model into the mainstream of contemporary general equilibrium analysis and to derive the implications of that model when, as in other equilibrium systems, trading occurs only at equilibrium prices. I found that classical assumptions, when applied to Metzler's model, lead to standard classical results, such as the neutrality of money. This is true for both the insideand outside-money versions of the model. In addition, because Metzler made inside money proportional to the price level, the application of classical equilibrium trading implies an indeterminate money supply and an indeterminate price level. All of this is familiar to Patinkin's readers. In his opening discussion and equations (1)-(9), Meir Kohn fairly describes my restatement of Metzler's model with equilibrium trading. But he denies the two propositions stated above. His approach is to seek different results by means of an alteration in the assumptions. Instead of following Metzler2 in letting M be endogenous while the central bank exogenously fixes X, he reverses these assumptions by having the central bank fix M and letting X be endogenous. results of this switch, he claims, are that (i) the price level is determinate, and (ii) money is no longer neutral except in the case of the first open market operation. Variations in assumptions often generate variations in results. However, the inability of the central bank to acquire real assets (whose nominal values are proportional to the price level) in exchange for money prevails no matter whether we let M or X be the instrument of policy. Every increase in M causes an increase in P in the same proportion and leaves the central bank in possession of no more real assets than before the monetary injection. indeterminacy of prices in a system in which fixed nominal claims are absent is, it appears, a robust result. These assertions may be demonstrated as follows. Kohn's first open market operation is imposed on his equations (10)-(12) in the three unknown, r, and X: The central bank creates a predetermined sum of dollars M, and uses it to purchase private securities at the equilibrium price P, (p. 1094). He finds that r is not altered by the open market operation while X falls from 1 to X 1 < 1, where (1 X) is the proportion of securities (common stock, i.e., claims on real assets)