【英语生活】一代宗师弗里德曼（中）

Friedman in CambridgeI first met Friedman in the 1950's when I was a second-year undergraduate at Cambridge where he had come on a sabbatical. Unfortunately, I had to share supervisions with another student who had no difficulty in deflecting him into general political conversation. Friedman once arrived early and started to read a copy of Shaw's contribution to Fabian Essays which was lying on the table. “There are three mistakes in the first few pages,” he said, referring to Shaw's excursion into marginal productivity theory in which he thought he could instruct his less well-read fellow Fabians.

For all Friedman's charm, I received from him one of the best put-down remarks I have ever encountered. He mentioned to me a letter he had received from Arthur Burns (later chairman of the Fed) saying that Eisenhower was turning out well as President. I expressed surprise, to which Friedman responded: “First, Burns has much better knowledge of Eisenhower. Secondly, given equal knowledge, I would prefer his opinion to yours.”

In the 1950s, Friedman was much better known for his advocacy of floating exchange rates than for monetarism. The background was the widespread concern about a supposed dollar shortage, which Friedman believed entirely due to overvalued exchange rates in Europe and elsewhere. “Sure,” he would say, “there is a dollar shortage in Britain - in exactly the same way as there is a dollar shortage for every US citizen.” He had the last laugh, as within a few years the supposed dollar shortage had turned into an equally mythical dollar surplus.

What I did not discover until many years later was that Friedman had been spitefully frozen out of much of the intellectual life of the Cambridge Economics Faculty. For instance, there was an absurdly-named “secret seminar” that discussed capital theory, where Friedman could have helped very much by cutting through some of the mathematical problems and bringing out the essentials, but from which he was excluded. What dismayed him most were the illiberal attitudes of some in the faculty who were theoretically on his side. An example was the late Professor Sir Denis Robertson, who always maintained reservations about Keynes and who advocated zero inflation decades before that became fashionable. But he shocked Friedman by defending vigorously the right of County Agricultural Committees to dispossess farmers they deemed inefficient. The Chicago professor's admiration for the founding fathers of British economics became tinged with perplexity at what so many contemporary English people were inclined to assert.

“Permanent Income” and Money

During the rest of his career, Friedman was largely occupied with the empirical testing of economic ideas. His major achievement was his Theory of the Consumption Function, published in 1957. which was the work most prominently mentioned in the citation for the Nobel Prize which he won in 1974. His investigation was touched off by a well known paradox. Cross-section data appeared to show that the percentage of income saved increased as income rose. On the other hand, time series data showed much less change in the savings proportion over the years. The resolution of the puzzle was that spending and savings decisions depended on people's views of their long-term (“permanent”) income; but they were much less inclined to adjust to transitory income variations in either direction.

These findings had at least two implications which Friedman cherished. One was that capitalism did not after all suffer from a long-term tendency to stagnate because of under-consumption. Another was that fiscal fine-tuning would be very difficult, as consumers would ignore temporary variations in disposable income due to government budgetary tightening or relaxation. Here indeed is the clue to why Chancellor Kenneth Clarke's 1994 tax increases did not have the recessionary effects so widely predicted. Friedman's Consumption Function was so thorough and convincing in its marriage of theory and data that it convinced many economists who far from relished the political implications.It was in the late 1950 and 1960s that Friedman developed the monetarist doctrines by which he became best known. He treated money as an asset. The public desire to hold this asset depended on incomes, the rate of interest and expected inflation. If more money became available the effect would be initially to raise real output and incomes, but eventually just to raise prices more or less in proportion. Here was where the famous ‘long and variable lags' appeared: typically nine months before real output and income were affected and a further nine months before the main effects on prices came through. These time periods were much cited and much derided; but they were not the heart of Friedman's message.

The stock response of the anti-monetarists was to say that the money supply adjusted passively to events such as wage explosions or government deficits. Although this sometimes occurred it was important for Friedman to establish that this was not always the case. Sometimes money was the active agent, whether because of an inflow of gold, an official easy money policy, an attempt to maintain a particular exchange rate, or whatever.

Monetary History and Monetarism

The book in which he tried most fully to demonstrate money's active role was A Monetary History of the US, 1867-1960, published in 1963 and written jointly with Anna Schwartz it was one of Friedman's skills that he always found the right collaborator for a particular work. The Monetary History is Friedman's masterpiece. Containing hardly any equations, it has been read with profit and pleasure as history, even by people who have disagreed with, or been indifferent to, the doctrines it was designed to advance. Characteristically, it began as a by-product of an attempt to establish the factual record of the US money supply, which turned up so many problems and brought to light so much new material that the more ambitious volume more or less suggested itself.

A later attempt by the same two authors at a more formal equation-based approach, concentrating on cyclical averages and covering the UK as well, was not as successful. There were so many snags that the results did not appear until 1982; and the authors themselves admitted that they were hardly worth the effort. They particularly regretted the time spent on extending the analysis to the UK, which had not yielded much extra light. The scholarly debate on the new work was itself delayed for nearly another decade, partly because of the attempts of British anti-Thatcherites to harness the analysis of Friedman's critics for their own political purposes. One day the story will be told.

The policy conclusion Friedman drew was his famous money supply rule a stable growth of the money supply, year in year out. He accepted that this was not the only policy that could be derived from monetarist findings. But nearly all suggested monetarist strategies became embroiled in difficulties as financial assets proliferated and with them the number of rival definitions of money. In the early 1990s some monetarists were accusing the Fed of depressing the US economy with too tight a policy and at the same time as other monetarists were criticising it for expanding too much.

Friedman himself sometimes gave the impression that whatever a central bank did, it could do no right. To gain his favour it had not only to pursue monetary targets, but pursue them by a particular method known as monetary base control; and when the Fed attempted such a method in 1979-82 it was damned for getting the mechanics wrong.

弗里德曼在剑桥我初遇弗里德曼是在上世纪50年代，当时我在剑桥大学(Cambridge)读二年级，他则在这里担任客座教授。不幸的是，我不得不与另外一位学生分享他的指导，而那位学生很容易就会把他引入一般的政治谈话之中。有一天，弗里德曼来得很早，开始阅读桌上放着的一本《费边论文集》(Fabian Essays)中萧伯纳(Bernard Shaw)的文章。他说道：“开头几页有三处错误。”他指的是萧伯纳对边际生产率理论的误解。萧伯纳以为，自己能够在这一领域为读书没他多的费边社同僚提供一些指导。

尽管弗里德曼极富魅力，但我也从他那里遭到了平生最大的奚落。他向我提及亚瑟•伯恩斯(Arthur Burns)（后来的美联储(Fed)主席）写给他的一封信，信中称艾森豪威尔(Eisenhower)实际上是一位出色的总统。我对此表示惊讶，弗里德曼回答道：“首先，伯恩斯更了解艾森豪威尔。其次，就算了解程度相同，我还是更愿意接受他的观点，而不是你的。”

在上世纪50年代，弗里德曼更知名的是对浮动汇率的提倡，而不是货币主义。当时市场普遍对美元短缺的假象感到担忧，而弗里德曼认为，这完全是由于欧洲和其它地方的汇率过高。“的确，”他会说，“英国缺少美元——这就和每个美国公民都缺少美元一模一样。”他笑到了最后，因为在短短几年内，美元短缺的假象就变成了同样神秘的美元过剩。

直到多年以后我才知道，弗里德曼在剑桥经济系(Cambridge Economics Faculty)期间，一直被恶意排挤在许多学术生活之外。例如，当时有一个讨论资本理论的名称怪异的“秘密研讨会”。本来，如果让弗里德曼来解决一些数学难题，揭示本质，可以为这个研讨会提供极大的帮助，但是他却被排斥在外。

最让弗里德曼寒心的，是经济系中某些与他持有相同理论观点的人的狭隘态度。已故教授丹尼斯•罗伯逊爵士(Professor Sir Denis Robertson)就是其中之一。罗伯逊爵士始终对凯恩斯持保留意见，而且倡导直到几十年后才为人们普遍接受的零通胀政策。但是让弗里德曼震惊的是，罗伯逊爵士为“郡县农业委员会”(County Agricultural Committee)的权力进行了积极辩护，认为它们有权踢开它们认为效率低下的农民。于是，这位芝加哥大学的教授对英国经济学创立者的崇敬之情平添了几分困惑，对如此多当代英国人打算维护的观点感到费解。

“永久收入”(Permanent Income)与货币

在后来的职业生涯中，弗里德曼主要致力于对经济学观点进行经验主义验证。他的主要成就是1957年出版的《消费函数理论》(Theory of the Consumption Function)。这是在他1974年荣获诺贝尔奖时提及得最多的一部著作。他的调查起因于一个众所周知的悖论。数据似乎表明，随着收入的增加，储蓄率也会增加。但是，时间序列(time series)数据显示，长期储蓄率的变动要小得多。对这个谜题的解释是，支出和储蓄决策取决于人们对自己长期(“永久”)收入的看法；人们往往不会根据短暂的收入变化对支出和储蓄进行调整。

这些发现至少包含弗里德曼推崇的两层含意。一个是，资本主义最终不会因为消费不足而出现停滞不前的长期趋势。另一个是，财政微调会非常困难，因为消费者会忽略政府预算收紧或放宽导致的暂时性可支配收入变化。的确，英国财政大臣肯尼斯•克拉克(Kenneth Clarke)1994年的增税措施没有产生人们广泛预期的衰退后果，这正是其中的原因所在。弗里德曼的消费函数在融合理论与数据方面如此彻底而又令人信服，说服了许多不赞同其政治含义的经济学家。

直到上世纪50年代末和60年代，弗里德曼才发展出货币主义学说，并因此一举成名。他将货币视为一种资产，公众持有这种资产的意愿取决于收入水平、利率和预期通货膨胀率。如果货币供应增加，那么最初的效果将会是提高实际产出和收入水平，但最终的结果将是或多或少地按比例提高价格。这就是著名的“长期、多变的滞后” (Long and Variable Lags)：一般情况下，需要9个月才会对实际产出和收入水平产生影响，再过9个月，对价格的主要影响才会体现出来。这些时间周期经常被引用，也经常被嘲笑，但它们并非弗里德曼的核心思想。

反货币主义者通常的反应是，货币供应会对薪资膨胀或政府赤字等事件做出被动调整。尽管虽然这种现象有时会出现，但弗里德曼需要确定，情况并非总是如此。有时候货币扮演着活性剂的角色，无论原因是黄金流入、官方放松货币政策，还是试图维持某一特定的汇率等。

货币历史和货币主义

弗里德曼曾在一本书中力求全面展现货币的积极作用，那就是《美国货币史，1867年至1960年》(A Monetary History of the US, 1867-1960)。该书由弗里德曼和安娜•施瓦茨(Anna Schwartz)合著，于1963年出版。这是弗里德曼的技巧之一，他总能为某项具体的工作找到一位恰当的合作者。《美国货币史》是弗里德曼的一项杰作。书中几乎没有公式，即便是对书中提出的学说持反对观点、或是对其漠不关心的人，将本书作为历史书来研读，也会为他们带来愉悦，并从中受益。本书符合弗里德曼的一贯特点，其本意是如实记录美国的货币供应历史，结果却找到了如此之多的问题，发现了如此之多的新材料，其较大的篇幅本身就多多少少说明了这一点。

这两位作者后来采用了基于方程式的更正式的方法进行研究，关注于周期平均值，并涵盖了英国的数据，但却没有那么成功。两位作者遇到了诸多障碍，研究结果直到1982年才出炉；他们自己也承认，实在不值得付出这么多努力。他们尤其后悔花时间对英国进行分析，这些分析没有为他们带来多少新的突破。围绕这本新著作的学术辩论又过了近10年才展开，其中的部分原因在于，英国的反撒切尔(Thatcher)势力试图将弗里德曼批评者的分析用于自己的政治目的。总有一天，内情将会曝光。

弗里德曼做出的政策结论是其著名的货币供应政策：年复一年稳定的货币供应增长。他承认，这不是唯一一个可以从货币主义理论中得出的政策。但是，随着金融资产的激增以及随之而来的大量对货币的不同定义，几乎所有的货币主义策略都遭遇了困境。上世纪90年代初，一些货币主义学家指责美联储(Fed)政策过紧，压制了美国经济的发展，但与此同时，其它货币主义学家则批评美联储扩张过快。

弗里德曼本人有时会给人留下这样的印象：无论一家央行做什么，都是错的。若想得到他的青睐，央行不仅要追求货币目标，而且在追求目标时还要采用一种名为货币基础控制(monetary base control)的特殊方式；当美联储1979年至1982年期间尝试采用这种方法时，外界谴责它把作用机制弄错了。

（待续）