【英语生活】一代宗师弗里德曼（下）

No Inflation-Jobs Trade-offSome economists would argue that Friedman's most important contribution to macroeconomics lay, not in his technical monetary work, but in his 1967 presidential address to the American Economic Association. Here he demonstrated that the idea of a stable trade-off between inflation and unemployment which held sway under the name of the Phillips curve and which seemed to give policymakers a menu of choices was invalid. Suppose that a Government or central bank tried to raise output and employment at the expense of accepting higher inflation. Once market participants started to take into account inflation in their behaviour, the economy would eventually end up with the same rate of unemployment as before but a higher rate of inflation. If the authorities none the less persisted in trying to achieve an over-ambitious target unemployment rate, the result would not be merely inflation, but accelerating inflation, with which no society could live for long.

This family of Friedman doctrines was sometimes called the vertical Phillips curve, sometimes the accelerationist hypothesis and sometimes the ‘natural rate' of unemployment.The latter was the level at which the economy would settle once any stable rate of inflation had been established. The name was later changed by some users to the Nairu the non-accelerating inflation rate of unemployment to banish the idea that there was anything natural or inevitable about it.

It was in fact these ideas related to the Nairu which caused my own conversion from post-war Keynesianism rather than any of Friedman's more technical monetary ideas. The basic propositions are now quite familiar. But at the time they were explosive stuff for the British economic establishment and also for many American economists on the Eastern seaboard.

Some economists treated the Nairu as a new technocratic concept which they set about estimating and using for still more sophisticated forms of demand management. This was contrary to the spirit of Friedman's address, where it was were obviously intended as a warning against government attempts to spend their way into pre-determined levels of employment. The Friedman ideas achieved popular currency in the UK amazingly enough as a result of prime minister Callaghan's address to the 1976 Labour Party conference when he warned against believing that governments could spend their way into full employment.

All the same it was a little disappointing to those who were interested in macroeconomics rather than monetary technicalities that Friedman did not make more use of the Nairu in his more popular writings. Indeed he sometimes seemed to stretch his own doctrines in attributing to short term variations in monetary growth the responsibility for recessions about which he could be as critical as any Keynesian.

Relations with Thatcher

Friedman's direct influence on Margaret Thatcher was much less than often supposed. Although they got on together at a private dinner before the 1979 election, the two did not know each other well and Friedman is only mentioned en passant in the former prime minister's memoirs. Her own inspiration, as she relates, came from Hayek.

Nevertheless, Friedman had an obvious, if indirect, effect on many of her advisers and ministers. The Medium Term Financial Strategy of the 1980s, with its target of a gradual reduction in the growth of the money supply and the abandonment of fine tuning, obviously stemmed at one remove or another from the Chicago economist.

But the master himself disowned the MTFS because the Bank of England continued to regulate the money supply through interest rates rather than via the monetary base. Moreover, he did not believe that reducing the Budget deficit would have much effect on interest rates or in any other way deserved the prominence given to it in the MTFS. On a broader front, however, without Friedman's writings and television expositions, the Thatcher government would not have enjoyed even that very limited degree of approval that it did among a minority of the intellectual elite.

A Working Retirement

From the late 1970s onwards Friedman lived in San Francisco. He obviously enjoyed his working retirement in this more clement climate, within easy reach of his office at the Hoover Institution in Stanford. Rose was even more obviously delighted with the move.

The very modernity of Friedman meant that he was vulnerable in his technical findings to new researchers claiming to refute his work by still more up to date statistical methods. Indeed, Friedman lived long enough to see a reaction against basing economics on discoverable numerical relationships and the revival of so-called Austrian methods which concentrated on predicting general features of interacting systems on the lines of biology and linguistics. But a methodological dialogue between different schools of free market economists would not have been possible without Friedman's initial dislodgment of the collectivists from the scientific high ground.

In the last couple of decades of his life, Friedman kept his distance from the New Classical Economics which was based on rational expectations and rapid market clearing. He feared that economists were being trapped into a search for mathematical rigour and elegance for their own sake instead of as tools for investigating what was happening.

Outside monetary affairs Friedman remained a mainstream economist. As he himself wrote in Capitalism and Freedom (a book published in 1962 which meant went much deeper than Free to Choose) he could offer no hard and fast line for the limits of government intervention. But he believed that an objective study of the facts, case by case, combined with an underlying belief in personal choice, would usually swing the argument in favour of private provision in the market place. His friend, Sir Alan Walters, has expressed regret, however, that he did not in his last decades devote more effort to scholarly work outside the monetary field.

Friedman himself attributed the spread of both free markets and monetarist ideas to belated recognition of the consequences of soaring government spending and high inflation in the 1970s. But so far as the reaction was coherent and rational, much of the credit must go to him. The very success of free market policies has, of course, led to fresh problems; and what would one not give for a reborn 30-year-old Milton Friedman to comment upon and analyse these new challenges?

通胀与失业之间不存在取舍关系一些经济学家会认为，弗里德曼对宏观经济学最重要的贡献，并非他对货币主义的专业研究，而是在他1967年担任美国经济协会(American Economic Association)会长时发表的就职演说。他在演说中论证：通胀与失业之间存在取舍关系的观点是错误的，这种观点以菲利普斯曲线(Phillips curve)的名义主导着当时的学术界，而且似乎为决策者提供了一系列政策选择。假定一国政府或央行试图以接受更高的通胀率为代价来增加产出和就业。一旦市场参与者开始将对通胀的考虑纳入行为中，经济最终将回到此前的失业率水平，但通胀率却上去了。如果政府还是坚持追求过高的就业目标，其结果将不仅仅是通胀，而且是任何社会都不可能长期忍受的加速通胀。

弗里德曼的这套学说有时被称作垂直的菲利普斯曲线，有时被称作加速主义假说，也有时被称作“自然失业率”。自然失业率指的是，在确定了稳定的通胀率后，经济中的失业率水平。后来，一些使用者将其更名为无加速通胀的失业率(non-accelerating inflation rate of unemployment, Nairu)，以摒弃其“自然”或“不可避免”的外表。

实际上，使我放弃战后凯恩斯主义的，正是这些有关无加速通胀的失业率(Nairu)的观点，而不是弗里德曼更为专业的货币主义理论。人们如今对这些基础理论已经很熟悉，但在当时，对于英国的经济界和美国东海岸的许多经济学家而言，这些理论极具爆炸性。

一些经济学家将无加速通胀的失业率视为技术学派的一个新概念，他们将其用于更复杂的需求管理形式。这违背了弗里德曼就职演说的精神。弗里德曼在演说中显然是打算警告政府：不要试图通过增加开支来实现预定的就业水平。英国首相卡拉汉(Callaghan)1976年在工党(Labour Party)大会上发表的演说，让弗里德曼的理论在英国得到了广泛认可。卡拉汉警告人们，不要相信政府通过增加支出，就能实现充分就业的观点。

然而，让那些对宏观经济而非货币主义理论感兴趣的人略感失望的是，弗里德曼在他更受欢迎的著作中，没有更多运用无加速通胀的失业率概念。的确，他有时似乎也会过分延伸自己的学说，将经济衰退的责任归咎于货币供应增长的短期变化。他对此的苛刻程度，不亚于任何一个凯恩斯主义者。

对撒切尔夫人的影响

弗里德曼对玛格丽特•撒切尔(Margaret Thatcher)产生的直接影响比人们通常想象的要小。尽管两人在1979年大选前的一个私人晚宴上相识，但彼此并不熟悉。这位英国前首相在回忆录中只是顺便提了一下弗里德曼。如她所述，她的灵感来自哈耶克(Hayek)。

然而，弗里德曼对她手下的许多顾问和大臣都产生了明显（即使是间接的）影响。英国上世纪80年代的中期财政战略(Medium Term Financial Strategy)将目标定为：逐渐减少货币供应增量，放弃政府的“微调”，这显然或多或少取自于弗里德曼的观点。

但这位经济大师本人不赞成中期财政战略，因为英国央行(Bank of England)对货币供应量的调节仍是通过利率而不是货币基础。此外，他不相信减少预算赤字会对利率产生巨大影响，而且他认为，无论从哪个角度讲，减少预算赤字都不应在中期财政战略中占有如此显著的位置。然而，从更广的范围看，没有弗里德曼的著作和电视演讲，撒切尔政府不会获得少数学界精英对其极为有限的认可。

退休后仍工作

自上世纪70年代末以来，弗里德曼一直居住在旧金山。他显然很享受自己“工作的退休生活”：这里气候比较温和，他很容易就能抵达在斯坦福大学(Stanford)胡佛研究所(Hoover Institution)的办公室。罗斯对这次搬家比他还高兴。

弗里德曼的这种现代性意味着，他的技术成果很容易受到新研究者的攻击，这些研究者声称要用更新的统计方法批驳他的成果。的确，在他的有生之年，弗里德曼看到了对将经济学基于可发现的数字关系的反对，也看到了所谓的奥地利方法的复兴，这种方法致力于用生物学和语言学的方式，来预测互动系统的总体特征。但是，如果没有弗里德曼先从科学高地上驱逐集体主义者(collectivists)，就不可能在不同流派的自由市场经济学家之间展开运用方法论的对话。

在他的后半生，弗里德曼与基于理性预期和快速市场清算的新古典经济学(New Classical Economics)保持着距离。他担心，经济学家已陷入了对数学严谨与数学优美的追寻，而不再将其作为研究工具。

在货币理论之外，弗里德曼依然是一位主流经济学家。就像他在《资本主义与自由》(Capitalism and Freedom，1962年出版，本意是为了对《自由选择》进行更深入的研究)一书中所写到的，他无法明确而快速地界定政府干预的局限。但他相信，对个案的客观研究，加之对个人选择的基本信念，通常会让辩论向有利于市场提供(private provision)的方向发展。然而，他的朋友亚伦•华特爵士(Sir Alan Walters)遗憾地表示，弗里德曼在下半生将主要精力投入了货币主义领域，而没有更多涉足其它领域的学术工作。

弗里德曼本人将自由市场和货币主义理论的胜出，归因于对70年代政府支出飙升和高通胀后果的滞后认识。然而，只要反应是连贯的和理性的，多数功劳就一定要归给他。当然，自由市场政策的成功也带来了新的问题；若能让30岁的米尔顿•弗里德曼重生，对这些新挑战进行评论和分析，我们有什么不可以付出呢？

译者/何黎