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| 经济学家日历：富兰克·H·奈特 |
作者： 发布时间：2007-11-25 15:21:43 来源： 点击数：76
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Frank Hyneman Knight
(November 7, 1885 - April 15, 1972)
富兰克·H·奈特（1885—1972年）是20世纪最有影响的经济学家之一，也是西方最伟大的思想家之一，他对于经济学发展和经济分析方法的创新做出了多方面的杰出贡献。“作为一个古典自由主义者，他是芝加哥学派的创始人；作为一个批评家，他告诫公众，经济学家的知识是有限的，其预测的失误是不可避免的；作为一名教师，他培养出了像弗里德曼、斯蒂格勒和布坎南这样著名的经济学家”。
1885年，奈特于出生在美国伊利诺伊州的一个农场里，1911年在田纳西州的米利根学院获学士学位，1913年在田纳西大学获硕士学位，同年，奈特进入康奈尔大学学习哲学，一年后开始学习经济学。1916年，奈特从康奈尔大学获得博士学位，其博士论文就是本书——《风险、不确定性和利润》。毕业后，奈特在康奈尔大学任教一年，然后在芝加哥大学任教两年，接着移居艾奥瓦，并在艾奥瓦大学晋升为教授。1927年，奈特回到芝加哥大学，成为在芝加哥大学历史上最具影响的经济学家，他一直在芝加哥大学工作到退休。
奈特也是美国经济学界最具权威性的人物之一，1950年他被推选为美国经济学会会长，1957年获弗朗西斯·沃尔克奖章（Francis Volcker Medal），这是美国经济学会的最高奖。奈特一生撰写过许多学术著作。除了《风险、不确定性和利润》（1921）外，主要还有《经济组织》（1933）、《竞争的伦理学及其他文论》（1935）、《自由与改革：经济学与社会哲学论文集》（1947）、《论经济学的历史与方法》（1956）以及《认知力与社会行动》（1960）等。
奈特指出：“自从我关注经济学以来，令我特别感兴趣的是经济学理论的含义、必要的假设条件，以及理论条件与现实条件之间的不一致性。”在《风险、不确定性和利润》一书中，奈特正是从理论条件下竞争与实际条件下竞争的不一致性出发，即从对完全竞争与不完全竞争的分析入手，通过引入不确定性概念，尤其是通过区分两种不同意义的不确定性概念，即风险与不确定性，揭示了理论上的完全竞争与实际竞争之间的本质区别，从而揭示了利润的来源。在这一过程中，奈特天才地研究和定义了企业和企业家的性质。
奈特认为，正如《风险、不确定性和利润》的书名所表明的那样，本书的理论体系是从收入分配理论中的利润问题出发，展开全书的分析过程。完全竞争的基本性质是不存在利润或亏损，商品的价值与成本完全相等，即产品价值被全部分配给各生产要素的所有者，没有剩余。但是，在现实社会中，成本与价值仅仅是“趋于”相等，即只是偶然完全相等。在一般情况下，它们之间一定会存在一个正的或负的“利润”，这样，利润就成为分析完全竞争与现实竞争之间不一致性问题的出发点。
（一）区分了风险与不确定性
为了说明利润的来源，奈特首先区分了两种不确定性。奈特指出，在本书中，我们将用“风险”指可度量的不确定性，用“不确定性”指不可度量的风险。正如我们已经指出的那样，利润理论之所以得以成立，正是因为真正的“不确定性”，而不是“风险”。具体讲，风险的特征是概率估计的可靠性，以及因此将它作为一种可保险的成本进行处理的可能性。估计的可靠性来自所遵循的理论规律或稳定的经验规律，对经济理论的目的来说，整个概率问题的关键点是，只要概率能够用这两种方法中的任一种以数字表示，不确定性就可以被排除。与可计算或可预见的风险不同，不确定性是指人们缺乏对事件的基本知识，对事件可能的结果知之甚少，因此，不能通过现有理论或经验进行预见和定量分析。
奈特区分风险与不确定性的哲学意义在于：风险是一种人们可知其概率分布的不确定，但是人们可以根据过去推测未来的可能性；而不确定性则意味着人类的无知，因为不确定性表示着人们根本无法预知没有发生过的将来事件，它是全新的、惟一的、过去从来没有出现过的。
（二）说明了利润起源
古典和新古典经济学的主要内容是价格机制，企业仅仅被抽象为利润最大化的生产者，即企业拥有完全的知识和预见，它总是遵循边际成本等于边际收益的原则进行生产，所以，在长期竞争均衡条件下，企业只能获得正常利润。为了批判这一理论，奈特用不确定性来说明在不完全竞争均衡条件下，利润存在的合理性。
奈特认为，在不确定性假设下，所有的生产决策是在知识有限的情况下作出的，以至于对可能出现结果的概率计算成为不可能。由于每个决策只产生一种惟一的结果，所以，个体决策所导致的一系列可能的结果不受统计计量的约束。经济学分析是在完全竞争假设下对经济运行机制的研究，完全竞争是一个使产品价值与其成本趋于一致的过程，但是，在现实中两者总存在一个差额，这个差额就是利润。也就是说，由于现实中的竞争并非完全竞争，理论与实际的不一致性造成了不确定性，从而不确定性是利润存在的基础。
奈特强调，变化不一定会导致利润的产生，因为有些变化可以事先精确地计算到成本中，使成本与产品售价相同，不会产生利润；只有不确定性能够将利润与变化联系在一起。利润的真正来源是不确定性，仅有变化和进步不足以产生利润，变化和进步的结果并不是其本身的结果，而是不确定性的结果。
（三）揭示了企业性质
我们知道，20世纪30年代，科斯曾向古典和新古典经济学提问：既然价格体系如此有效，为什么现代经济里还有依赖行政命令运行的企业存在呢？奈特最先回答这个问题。尽管科斯并不同意奈特的观点，但奈特对企业起源和性质的讨论对包括科斯在内的所有经济学家，尤其是新制度经济学家都有着深远的影响。
奈特认为，在不确定性的假设下，决定生产什么与如何生产优先于实际生产本身，这样，生产的内部组织就不再是一件可有可无的事情了。生产的内部组织首先是要找到一些最具管理才能的人，让他们负责生产和经营活动。世界上只有少数人是风险偏好者，而绝大部分人是风险规避和风险中性者，后者愿意交出自己对不确定性的控制权，但条件是风险偏好者即企业家要保证他们的工资，于是，企业就产生了。也就是说，在企业制度下，管理者通过承担风险获得剩余；工人通过转嫁风险获得工资。
为了说明企业家和企业的性质，奈特的基本分析思路为：现实的经济过程是由预见未来的行动构成的，而未来总是存在不确定因素的，企业家就是通过识别不确定性中蕴含的机会，并通过对资源整合来把握和利用这些机会获得利润。沿着这一思路，奈特分析了企业的性质和在现代化生产条件下企业存在的理由，不确定性的存在意味着人们不得不预测未来的需要。首要的问题和职能是决定做什么和怎样去做，因此出现了一个特殊阶层，他们向他人支付有保证的工资，并以此控制他人的行动功能的多层次专业化的结果是企业和产业的工资制度，它在世界上的存在是不确定性这一事实的直接结果。
（四）提出了减少不确定性的方法
在本书中，奈特还分析了减少不确定性的两种方法。一是集中化，保险就是这种形式的代表。保险公司利用不确定性结果的相互抵补，将众多偶然事件集中到一起，从而把投保者的较大不确定性损失转变成较小的保险费。二是专业化，企业的联合有助于克服不确定性。企业通过增加生产规模可以减少不确定性的控制成本，因为大企业的成本水平总是低于小企业。随着企业规模的增加，专业化决策能够减少控制成本的不确定性，同时也能产生更熟练的技能，以更好地应对不确定性。
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KNIGHT, Frank Hyneman (1885-1972)
Frank Hyneman Knight was born in McLean County, Illinois on 7 November 1885 and died in Chicago Illinois on 15 April, 1972, at the age of 87. He was educated at the University of Tennessee, where he earned a bachelor’s degree in the natural sciences and a master’s degree in German and at Cornell University where he obtained his Ph.D. in economics in 1916. Following his graduation from Cornell, he taught at the University of Iowa for eight years (1919-1927) before moving to the University of Chicago where he was a an economic professor from 1927 until 1955 and an emeritus professor until his death.
Knight made his reputation with his Risk, Uncertainty, and Profit (1921), which was based on his Ph.D. dissertation. In this work, Knight attempted to explain why profits would not necessarily be eliminated under perfect competition. In providing his explanation he made the key distinction between “risk” and “uncertainty”. Risk was a situation, according to Knight, which one could assign a probability too and therefore could be insured against. In contrast, uncertainty was a situation for which the probability was unknown. Even in long-run equilibrium, Knight contended, entrepreneurs would earn a profit as a return for having to face uncertainty. Knight noted that a model which eliminates risk and uncertainty would also lack profit and as such, the standard model of perfect competition does cannot have profit in the economic sense.
Another contribution by Knight to economics in this period was his article, “Some Fallacies in the Interpretation of Social Costs” (1924). In this article Knight addressed Pigou’s conclusion that road congestion justified the taxation of roads. Knight argued that no government intervention was necessary. If roads were privately owned, the owners would reduce congestion by raising tolls raising the price of using the roads.
Knight was brought to Chicago in 1927 to teach history of economic thought although he taught economic theory as well. He also developed a course on economics and social policy which he co-taught with the philosopher Charner Perry. In 1933, The Economic Organisation, a set of Knight’s lecture notes was published. This book was used as part of the introductory course in the social sciences for undergraduates at the University of Chicago.
In addition to his work in economics, Knight was also a social philosopher and many of his writings reflect this. Knight was concerned about whether the public could understand the simplest economic truths as expressed in his 1950 presidential address to the American Economic Association. Knight was a proponent of laissez-faire as evidenced in his “The Ethics of Competition” (1923). Knight argued that the capitalist system could not be defended on ethical grounds. The economy, Knight argued, is too complex for government to understand. Government programs and interventions are too simplistic and the unintended consequences of intervention are more dangerous than the market outcome.
Knight’s work in economics and social philosophy was also complimented with his realization regarding the importance of history. In The Ethics of Competition and Other Essays (1935), he argued that there was an “impassible gulf” between equilibrium states in economic theory and the path taken by the economy in reality. This required, according to Knight, a historical examination which cannot assume the movement toward equilibrium. For Knight, the market was morally suspect but so were orders from
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government. Laissez-faire is preferable because it holds individual freed as an absolute and the alternative is potentially much worse.
Knight was named president of the American Economic Association (AEA) in 1950 and he was awarded the AEA’s Francis Walker Medal in 1957. This award was presented every five years “to the living American economist who has made the greatest contribution to economics.” He was a Fellow of the American Academy of Arts and Sciences as well as the Italian national honor society, Accademia Nazionale De Lincei. Knight was selected by the U.S. Chamber of Commerce for its Great Living American Awards in 1959. His notable students include Milton Friedman, the 1976 Nobel Prize winner in Economics, George J. Stigler, the 1982 Nobel Prize winner in economics, James M. Buchanan the 1986 Nobel Prize winner in economics, Kenneth Boulding, a Commonwealth fellow and Paul Samuelson as an undergraduate.
BIBLIOGRAPHY
Risk, Uncertainty, and Profit (Boston, 1921).
“The Ethics of Competition,” Quarterly Journal of Economics (1923), 37: 579-624.
”Some Fallacies in the Interpretation of Social Cost,” Quarterly Journal of Economics (1924), 38: 582-606.
The Economic Organisation (Chicago, 1933)
The Ethics of Competition and Other Essay (Chicago, 1935).
Freedom and Reform: Essays in Economics and Social Philosophy (Chicago, 1947).
Other Relevant Works
Selected Essays by Frank H. Knight. Volume 1: “What is Truth” in Economics? Ross B. Emmett, ed. (Chicago, 1999).
Selected Essays by Frank H. Knight. Volume 2: Laissez-Faire: Pro and Con. Ross B. Emmett, ed. (Chicago, 1999).
Further Reading
Boettke, Peter J. and Karen I. Vaughn. "Knight and the Austrians on Capital and the Problem of Socialism," History of Political Economy, 34 (1) 2002: 153-174.
Ross, Emmett B. "Frank Hyneman Knight (1885-1972): A Bibliography of His Writings.” Research in the History of Economic Thought and Methodology, Warren J.
Samuels and Jeff Biddle, eds., archival supplement 9, 1999, pp. 1-100.863 words
Peter J. Boettke and Christopher J. Coyne James M. Buchanan Center for Political Economy George Mason University
Frank Hyneman Knight (1885-1972)
Frank H. Knight was one of the founders of the so-called Chicago school of economics, of which Milton Friedman and George Stigler were the leading members from the fifties to the eighties. Knight made his reputation with his book Risk, Uncertainty, and Profit, which was based on his Ph.D. dissertation. In it Knight set out to explain why perfect competition would not necessarily eliminate profits. His explanation was "uncertainty," which Knight distinguished from risk. According to Knight risk refers to a situation where the probability of an outcome could be determined, and therefore, the outcome could be insured against. Uncertainty, by contrast, referred to an event whose probability could not be known. Knight argued that even in long-run equilibrium, entrepreneurs would earn profits as a return for their putting up with uncertainty. Knight's distinction between risk and uncertainty is still taught in economics classes today.
Knight made three other important contributions to economics. One was The Economic Organization, a set of lecture notes originally published in 1933. In it he lays out the circular flow model of the economy and emphasizes that investments will be made until the returns to investments in each use are equal at the margin. These elements still survive in textbooks today.
Another of Knight's contributions to economics was in his famous article "Some Fallacies in the Interpretation of Social Cost," in which he took on Pigou's view that congestion of roads justified taxation of roads. Knight showed that if roads were privately owned, road owners would set tolls that would reduce congestion. Therefore, no government intervention was required.
Knight's final contribution was his work on capital theory in the thirties. Knight criticized B鰄m-Bawerk's view that capital could be measured as a period of production (see B鰄m-Bawerk). Knight was seen to have won the debate over the Austrian concept of capital.
But Knight was much more than an economist. He was also a social philosopher, and most of his writings were in social philosophy rather than technical economics. A strong believer in freedom and a strong critic of social engineering, Knight worried that freedom would be undermined by increases in monopoly and in income inequality. George Stigler tells of Milton Friedman challenging Knight's view that inequality would increase, and Knight's relenting, only to take the same position at the next lunch.
Knight often despaired about whether even simple economic truths could be understood by the public. In his 1950 presidential address to the American Economic Association, Knight said:
Of late I have a new and depressing example of popular economic thinking, in the policy of arbitrary price-fixing. Can there be any use in explaining, if it is needful to explain, that fixing a price below the free-market level will create a shortage and one above it a surplus? But the public oh's and ah's and yips and yaps at the shortage of residential housing and surpluses of eggs and potatoes as if these things presented problems any more than getting one's footgear soiled by deliberately walking in the mud.
Knight was an economics professor at the University of Chicago from 1927 until 1955, after which he was emeritus professor until his death.
Selected Works
The Economic Organisation. 1951.
The Ethics of Competition, and Other Essays. 1935.
Freedom and Reform: Essays in Economics and Social Philosophy. 1947. Reprint, edited by J. M. Buchanan. 1982.
Risk, Uncertainty, and Profit. 1921.
"Cost of Production and Price Over Long and Short Periods," Journal of Political Economy vol. 29, no. 4 (1921): 304-335.
"Some Fallacies in the Interpretation of Social Cost." Quarterly Journal of Economics 38 (1924): 582-606.
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