一昨日のエントリでは、Stephen Williamsonボール=マンキュー論文に対するルーカスの批判を紹介したことに触れた。その論文は「Sticky Price Manifesto」と題されてる。以下はその冒頭部。

There are two kinds of macroeconomists. One kind believes that price stickiness plays a central role in short-run economic fluctuations. The other kind doesn't.
Those who believe in sticky prices are part of a long tradition in macroeconomics. This tradition includes prominent twentieth-century economists such as John Maynard Keynes, Milton Friedman, Franco Modigliani, and James Tobin, and it dates back at least to David Hume. The assumption of sticky prices is an essential underpinning of the IS-LM model, which is taught almost universally to undergraduates as the theory of short-run fluctuations. Traditionalists believe that this model contains a large element of truth.
By contrast, those who deny the importance of sticky prices depart radically from traditional macroeconomics. These heretics hold disparate views: some argue that fluctuations arise from technological shocks to competitive economies while others emphasize non-Walrasian phenomena such as increasing returns and sunspot equilibria. Nonetheless, heretics are united by their rejection of propositions that were considered well-established a generation or more ago. They believe that we misled our undergraduates when we teach them models with sticky prices and monetary non-neutrality.
A macroeconomist faces no greater decision than whether to be a traditionalist or a heretic. This paper explains why we choose to be traditionalists. We discuss the reasons, both theoretical and empirical, that we believe in models with sticky prices. And we survey recent research in this paradigm, highlighting both the new discoveries and the questions that remain open for future work. Recent research both strengthens the foundations of traditional models and extends the range of phenomena that these models can explain.
Our dictionary defines "manifesto" as "a public declaration of principles or intentions." This word describes perfectly what we try to do in this paper. Rather than present new theoretical or empirical results, we attempt to set out what we believe and why we believe it. Of course, our goal is to persuade others. We realize that what follows will not convert a confirmed heretic. But we hope that it will persuade readers who have not yet made up their minds.


The cost of the ideological approach adopted by Ball and Mankiw is that one loses contact with the progressive, cumulative science aspect of macroeconomics. In order to recognize the existence and possibility of research progress, one needs to recognize deficiencies in traditional views, to acknowledge the existence of unresolved questions on which intelligent people can differ. For the ideological traditionalist, this acknowledgement is too risky. Better to deny the possibility of real progress, to treat new ideas as useful only in refuting new heresies, in getting us back where we were before the heretics threatened to spoil everything. There is a tradition that must be defended against heresy, but within that tradition there is no development, only unchanging truth.

A few years ago, one of my sons used the Samuelson-Nordhaus textbook in a college economics course. When I visited him, I looked at the endpaper of the book to see if actual GNP was getting any closer to potential GNP than it had been in the edition I had used many years earlier. But the old chart was gone, and in its place was a kind of genealogy of economic thought, with boxes for Smith and Ricardo at the top, and a complicated picture of boxes connected by lines, descending down to the present day. At the bottom were three boxes: On the left, a box labelled “Communist China”; in the center, and slightly larger than the rest, a box labelled “Mainstream Keynesianism.” The last box, on the right, was labelled “Chicago monetarism.”
Times change. Accordingly, to Ball and Mankiw, Chicago monetarism (or at least Milton Friedman) now shares the middle, mainstream box, and there is a new group for the right-hand box, to be paired with the Chinese communists. But the tradition of argument by innuendo, of caricaturing one’s unnamed opponents, of using them as foils to dramatize one’s own position, continues on. I am sorry to see it perpetuated by Ball and Mankiw, and I hope they will put it behind them and return to the research contributions we know they are capable of making.





*2:少なくともWilliamsonは、ルーカスの講演資料の結論部の「Is it possible that by imitating European policies on labor markets,welfare, and taxes U.S. has chosen a new, lower GDP trend?/If so, it may be that the weak recovery we have had so far is all the recovery we will get」という表現を元にそう解釈している(「Now it's clear, at least to me, that Lucas is just throwing out an idea for discussion. Lucas is a scientist, of course, and he's not going to commit himself to some view without solid research to back it up. That's why he uses words like "is it possible..." 」)。ただその結論部の直前にルーカスは「Is this because government is not spending enough?/Believe it is more accurate to say that the problem is government is doing too much」というより強い表現をしており、例えばMark Thomaはむしろそちらに反応している。