03不确定性、进化和经济理论(中英).docx

UNCERTAINTY, EVOLUTION, AND ECONOMIC THEORY 不确定性、进化和经济理论ARMEN A. ALCHIANUniversity of California at Los AngelesA modification of economic analysis to incorporate incomplete information and uncertain foresight as axioms is suggested here. 本文提出一种经过改进的经济分析方法，以将不完全信息和不确定预知作为不言自明的客观存在引入经济分析。This approach dispenses with “profit maximization”; and it does not rely on the predictable, individual behavior that is usually assumed, as a first approximation, in standard textbook treatments. 这一分析方法扬弃了“利润极大化”；同时放弃了个体行为的可推测性，而在一般的教科书中，个体行为的可推测性通常被假定为一个最基本的条件。Despite these changes, the analytical concepts usually associated with such behavior are retained because they are not dependent upon such motivation or foresight. 尽管作了上述两点修正，但进行这类行为分析时常用的那些概念仍旧保留下来，因为这些分析概念本身并不依赖于这种动机或预见。The suggested approach embodies the principles of biological evolution and natural selection by interpreting the economic system as an adoptive mechanism which chooses among exploratory actions generated by the adaptive pursuit of “success” or “profit.” 这里提出的这种分析方法吸收了生物进化和自然选择原理，把经济体系解释为一个甄别机制，这一机制具有甄选那些试图追逐“成功”或利润“的适应性行为的功能。The resulting analysis is applicable to actions usually regarded as aberrations from standard economic behavior as well as to behavior covered by the customary analysis. 用这一方法，不仅能对那些通常被视为异常的经济行为进行分析，而且亦适用于传统分析所包括的一切行为分析。This wider applicability and the removal of the unrealistic postulates of accurate anticipations and fixed states of knowledge have provided motivation for the study. 这一分析方法剔除了“精确预期”和“固态知识”这两个不真实的假说，其更广泛的适用性为经济学研究提供了动力。The exposition is ordered as follows: First, to clear the ground, a brief statement is given of a generally ignored aspect of “profit maximization,” that is, where foresight is uncertain, “profit maximization” is meaningless as a guide to specifiable action. 本文将进行的阐释如下：首先，需要明确的是，“利润最大化”有一个方面的简要阐述被普遍忽略了，即，当预见具有不确定性的时候，“利润最大化”作为某一具体行动的指导是没有什么意义的。The constructive development then begins with an introduction of the element of environmental adoption by the economic system of a posteriori most appropriate action according to the criterion of “realized positive profits.” 其次，建设性的发展起自一个环境选择原理的引入，这个环境选择原理是一个后验的经济体系，其最适宜行为依据的是“实现净利润”而非“利润最大化”准则。This is illustrated in an extreme, random-behavior model without any individual rationality, foresight, or motivation whatsoever. Even in this extreme type of model, it is shown that the economist can predict and explain events with a modified use of his conventional analytical tools. 这表明了即使在没有丝毫个体理性、预见性或者动机性的极端随机行为模型中，经济学家也能够通过对传统分析工具进行的一些修正，来预测和解释事件。This phenomenonenvironmental adoptionis then fused with a type of individual motivated behavior based on the pervasiveness of uncertainty and incomplete information. 再次，在普遍存在不确定性和不完全信息的世界中，环境选择这一现象和一类个体的动机性行为相融合。Adaptive, imitative, and trial-and-error behavior in the pursuit of “positive profits” is utilized rather than its sharp contrast, the pursuit of “maximized profits.” 对照利润最大化的追求，在净利润追求过程中的那些适应性、模仿性和试错性行为将被更好的利用。A final section discusses some implications and conjectures. 最后，本文将讨论基于这些原理的一些影响及推测。. “PROFIT MAXIMIZATION” NOT A GUIDE TO ACTIONI.利润最大化并非是行动的指导Current economic analysis of economic behavior relies heavily on decisions made by rational units customarily assumed to be seeking perfectly optimal situations. 当今经济分析中，经济行为严重依赖于理性单位所做的决定，即在传统假设中，理性个体总是谋求一个完美的最优情况。Two criteria are well knownprofit maximization and utility maximization. 这个最优情况有两个众所周知的准则：利润最大化和效用最大化。According to these criteria, appropriate types of action are indicated by marginal or neighborhood inequalities which, if satisfied, yield an optimum. 根据这两个标准，当边际上或者临域间（收益）不相等的时候，人们就总是会有相宜类型的（改进）行动，直到最终达成最优状况。But the standard qualification usually added is that nobody is able really to optimize his situation according to these diagrams and concepts because of uncertainty about the position and, sometimes, even the slopes of the demand and supply functions. 然而，标准的限定条件通常表明，因为个体并不清楚关于自身所处地位的状况和供给需求函数的斜率，所以通常没有人真能根据这些图表或概念从而最优化其自身的境况。 Nevertheless, the economist interprets and predicts the decisions of individuals in terms of these diagrams, since it is alleged that individuals use these concepts implicitly, if not explicitly. 尽管如此，经济学家对于个体决定的解释和推断仍然基于这些图表和概念，因为经济学家们断言，个体即便不是明确地，也会在无意识进行选择时使用这些图表或者概念。Attacks on this methodology are widespread, but only one attack has been really damaging, that of G.Tintner. 对这个方法论的抨击是非常广泛和普遍的，但是只有一个抨击是真正具有毁灭性的，来自G.Tintner教授。He denies that profit maximization even makes any sense where there is uncertainty. 他认为由于不确定性的存在，利润最大化已经变的毫无意义。Uncertainty arises from at least two sources: imperfect foresight and human inability to solve complex problems containing a host of variables even when an optimum is definable. 即使“最优化”可被定义，但不确定性至少仍来源于两方面：1）不完美的预见性；2）面对复杂或者包含多变量的问题时，人类的能力是十分有限的。Tintners proof is simple. Under uncertainty, by definition, each action that may be chosen is identified with a distribution of potential outcomes, not with a unique outcome. Tintner教授的论据很简单，根据定义，在不确定性下，每一个可能被选择的行动都将被等同于由众多潜在结果组成的一个（概率）分布，这意味着结果并不唯一。Implicit in uncertainty is the consequence that these distributions of potential outcomes are overlapping. 这也暗含着，不确定性会使得潜在的众多结果的（概率）分布会重叠起来。It is worth emphasis that each possible action has a distribution of potential outcomes, only one of which will materialize if the action is taken, and that one outcome cannot be foreseen. 值得强调的是，每一个可能的行动都会对应一个由众多潜在结果组成的（概率）分布，当某一行动被实施，分布中的一个结果就会被具体化(Materialize)，而这个（被具体化的）结果是难以被预知的。Essentially, the task is converted into making a decision (selecting and action) whose potential outcome distribution is preferable, that is, choosing the action with the optimum distribution, since there is no such thing as a maximizing distribution. 本质上，这个任务将被转变为这样一个过程，即某人依据对潜在结果（概率）分布的偏好做出一个决定（选择并行动），这也意味着，这个人所能做的只是选择一个最优的（概率）分布，因为无法对一个“概率分布”进行最大化或最优化。For example, let each of two possible choices be characterized by its subjective distribution of potential outcomes. 例如，分别将两种可能的选择逐一描述为主观下潜在结果的（概率）分布。Suppose one has the higher “mean” but a larger spread, so that it might result in larger profits or losses, and the other has a smaller “mean” and a smaller spread. 设想其中一个分布有较高的均值但是分布非常广，这意味着结果不是大规模盈利就是大规模亏损；而另一个选择的平均值较小但分布相对窄。Which one is the maximum? This is a nonsensical question; but to ask for the optimum distribution is not nonsense. 若此，哪一个是最优选择呢？这成了一个没有意义的问题；但是，要求一个最优（概率）分布不是没有意义的。In the presence of uncertainty a necessary condition for the existence of profitsthere is no meaningful criterion for selecting the decision that will “maximize profit.” 故而当存在不确定性的时候因为不确定性是利润存在的一个必要条件让人们进行一个选择，而这个选择所谓的能够“最大化其利润”就变毫无意义了。 The maximum-profit criterion is not meaningful as a basis for selecting the action which will, in fact, result in an outcome with higher profits than any other action would have, unless one assumes nonoverlapping potential outcome distributions. 事实上，除非假定没有重叠的潜在结果的（概率）分布，否则将“最大化利润”这一准则作为优于任何行动选择的原则都是没有什么意义的。It must be noticed that the meaningfulness of “maximum profitsa realized outcome which is the largest that could have been realized from the available actions”is perfectly consistent with the meaninglessness of “profit maximization”a criterion for selecting among alternative lines of action, the potential outcomes of which are describable only as distributions and not as unique amounts. 必须要注意的是，在这个意义下得到的“最大化利润即可以被现有行为实现的最大的利润结果”正好完美的与前面我们所说的那没有什么意义的“利润最大化”相一致了。所以，利润最大化可以看成这样一种准则，即一个在可选的活动形式中进行挑选而其潜在结果只可描述为非唯一数量的概率分布的准则。This crucial difficulty would be avoided by using a preference function as a criterion for selecting most preferred distributions of potential outcomes, but the search for a criterion of rationality and choice in terms of preference functions still continues. 这一具有决定性的难点却通过一个简单的偏好函数而被回避掉了。这个偏好函数是作为一个选择最佳潜在结果概率分布的准则出现的，但是我们还始终难以查探清两件事清：1）理性准则；2）有关偏好函数方面的选择标准。For example, the use of the mean, or expectation, completely begs the question of uncertainty by disregarding the variance of the distribution, while a “certainty equivalent” assumes the answer. 例如，只期望用平均数或期望的来完全应对不确定性问题但漠视概率分布的方差，而这却是用一个“确定性的等价物”假定的给出了答案（而并非不确定性）。The only way to make “profit maximization” a specially meaningful action is to postulate a model containing certainty. Then the question of the predictive and explanatory reliability of the model must be faced. 所以，唯一能够赋予“利润最大化”一个特别意义的行动是假定一个包含确定性的模型。随后我们必须面对问题的可预测性和模型解释的可靠性。. SUCCESS IS BASED ON RESULTS, NOT MOTIVATIONII.成功是基于结果而非动机There is an alternative method which treats the decisions and criteria dictated by the economic system as more important than those made by the individuals in it. 此时有一个替代方法，即认为经济系统的决策和准则比其中的个体要重要的多。 By backing away from the treesthe optimization calculus by individual unitswe can better discern the forest of impersonal market forces. 人们常常只见树木而不见森林专注于个体单位进行最优化计算，而这导致了我们难以更好的识别非人格化的市场力量。This approach directs attention to the interrelationships of the environment and the prevailing types of economic behavior which appear through a process of economic natural selection. 这一方式将我们的注意力引向优势的经济行为和环境之间的相互联系，即通过一个“经济自然选择”的过程而展现出来。Yet it does not imply that individual foresight and action do not affect the nature of the existing state of affairs. 当然，这并不意味着个体的预见和行动不能影响那些自然存在的状态。In an economic system the realization of profits is the criterion according to which successful and surviving firms are selected. 在一个经济体系中，利润的实现是一个准则，这个准则是按照“哪些公司能够成功存活下来”进行的筛选。This decision criterion is applied primarily by an impersonal market system in the United States and may be completely independent of the decision processes of individual units, of the variety of inconsistent motives and abilities, and even of the individuals awareness of the criterion. 这一決策准则在美国最先被应用于一个非人格化的市场体系中，这一准则可能是完全脱离个体单位决策过程的，并且与繁杂的非连续性动机和能力无关，甚至不管个体单位是否意识到这一准则。 The reason is simple. Realized positive profits, not maximum profits, are the mark of success and viability. 原因很简单。实现净利润是成功和生存能力的标志，而不是最大化利润。It does not matter through what process of reasoning or motivation such success was achieved. 对于达到某种程度的成功，无所谓其依据的是怎样的推理过程或动机。The fact of its accomplishment is sufficient. “具有成就”这一事实本身就已经足够了。This is the criterion by which the economic system selects survivors: those who realize positive profits are the survivors; those who suffer losses disappear. 这是经济系統筛选幸存者的一种准则，即，那些能够实现净利润的成为幸存者；而遭受损失的则会自动消失。The pertinent requirementpositive profits through relative efficiency is weaker than “maximized profits,” with which, unfortunately, it has been confused. 然而，遗憾的是，相对效率下净利润的相关要求要低于“利润最大化”，这使得人们感到困惑。Positive profits accrue to those who are better than their actual competitors, even if the participants are ignorant, intelligent, skilful, etc. 净利润归属于那些在竞争者中出类拔萃的人，而无所谓参与者是愚蠢的，聪明的，还是娴熟的。the crucial element is ones aggregate position relative to actual competitors, not some hypothetically perfect competitors. 决定性要素是实际竞争者在总体之中的相对地位，这意味着纵然所有的竞争者都是废柴也无所谓。As in a race, the award goes to the relatively fastest, even if all the competitors loaf. 这就好比一场赛跑，即使所有参赛选手都慢不经心，那个相比之下跑得最快的选手就会得奖。Even in a world of stupid men there would still be profits. Also, the greater the uncertainties of the world, the greater is the possibility that profits would go to venturesome and lucky rather than to logical, careful, fact-gathering individuals. 即使在一个白痴的世界中，也仍然会有利润。而当世界之中的不确定性越大，则利润更可能的被那些敢于冒险的幸运之人攫取，而非那些理性的、细心的、务实的人。The preceding interpretation suggests two ideas. First, success (survival) accompanies relative superiority; and, second, it does not require proper motivation but may rather be the result of fortuitous circumstances. 前面的解释暗含了两个意思。第一，成功（幸存）常常意味着相对优等；第二，并不需要所谓合理的动机，而更可能是一个具有偶然性的（优势）环境结果罢了。Among all competitors, those whose particular conditions happen to be the most appropriate of those offered to the economic system for testing and adoption will be “selected” as survivors. 在所有竞争者中，那些具有特殊条件的人恰好成为了在这个经济体系下最适宜的竞争者，这些幸存者是通过了环境的考验和采纳而“被选择”的。 Just how such an approach can be used and how individuals happen to offer these appropriate forms for testing are problems to which we now turn. 下面，我们转向研究“如何应用这样的方式”以及“个体如何碰巧提供适当条件供经济系统进行选择”。. CHANCE OR LUCK IS ONE METHOD OF ACHIEVING SUCCESSIII.偶然性和运气是一种达到成功的方式Sheer chance is a substantial element in determining the situation selected and also in determining its appropriateness or viability. 在进行环境筛选以及测定（个体）适宜性或生存能力时，绝对的偶然性是一个基本要素。A second element is the ability to adapt ones self by various methods to an appropriate situation. 第二个要素则是在相应情况下，个体自我多变的适应能力。In order to indicate clearly the respective roles of luck and conscious adapting, the adaptive calculus will, for the moment, be completely removed. 为了清楚的阐述“运气”和“自主适应”各自的作用，我们暂且先将这种关于自主适应的演算完全抛开。All individual rationality, motivation, and foresight will be temporarily abandoned in order to concentrate upon the ability of the environment to adopt “appropriate” survivors even in the absence of any adaptive behavior. 所有个体的理性、动机和前瞻性也将被暂时的放到一边，这样我们可以集中讨论环境的力量，以便在缺乏任何适应性行为的环境下，也可以选择出合适的幸存者。This is an apparently unrealistic, but nevertheless very useful, expository approach in establishing the attenuation between the ex post survival criterion and the role of the individuals adaptive decision criterion. 虽然这个假设和真实世界相去甚远，然而需要说明的是，这个假设仍然非常有用，即，我们的解释方式是通过弱化“事后生存准则”和“个体适应性决策准则作用”之间的关系而建立的。It also aids in assessing the role of luck and chance in the operation of our economic system. 另外，这个处理非常有助于我们评估运气和偶然性在我们的经济运行运行过程中的作用。Consider, first, the simplest type of biological evolution. 首先，让我们考虑最简单的生物演化类型。Plants “grow” to the sunny side of buildings not because the “want to ” in awareness of the fact that optimum or better conditions prevail there but rather because the leaves that happen to have more sunlight grow faster and their feeding systems become stronger. 植物生长在室外的阳光下，并非是因为它们“想要”意识到某种“最优”的事实或者认为阳光下是更优的条件，而是因为叶子恰好能在阳光下更快速的生长并使得它们的给养系统更强壮。Similarly, animals with configurations and habits more appropriate for survival under prevailing conditions have an enhanced viability and will with higher probability be typical survivors. 同样在一般环境下，动物的那些适宜于生存的构造和习性，使得它们具有了强大的生存能力,并且这也会使得它们更大可能的在以后也存活下去。Less appropriately acting organisms of the same general class having lower probabilities of survival will find survival difficult.而那些行动并不适宜的同类生物体则会发现它们的生存是非常困难的，即它们的存活概率较低。More common types, the survivors, may appear to be those having adapted themselves to the environment, whereas the truth may well be that the environment has adopted them. 还有更多普遍的类型，幸存者可能显出来的是它们对于环境的适应能力，然而事实更可能是环境已经选择采纳了它们。There may have been mo motivated individual adapting but, instead, only environmental adopting. 所以，这意味着没有什么动机性的个体适应，有的只是环境的选择接纳。A useful, but unreal, example in which individuals act without any foresight indicate the type of analysis available to the economist and also the ability of the system to “direct” resources despite individual ignorance, 一个有用但并不真实的假设，例如上面所说的，没预见性的个体行动意味着个体无知时，经济学家的分析模式和系统指导资源的能力仍然是有效的。assume that thousands of travelers set out from Chicago, selecting their roads completely at random and without foresight. 假设千百名旅者从芝加哥出发，完全没有什么预见性的随机选择各自的道路。Only our “economist” knows that on but one road are there and gasoline stations. 只有我们的经济学家知道一条路上有加油站。He can state categorically that travelers will continue to travel only on that road; those on other roads will soon run out of gas. 他完全可以直截了当的说只有在这条有加油站的路上的旅者能够继续前行，而其他路上的旅者将很快用完汽油。Even though each one selected his route at random, we might have called those travelers who were so fortunate as to have picked the right road wise, efficient, foresighted, etc. 即使每一个人都是随机选择其线路，我们也可以称那些因运气好而选到正确道路的旅者为聪明的、有效率的、有预见性的。of course, we would consider them the lucky ones. If gasoline supplies were now moved to a new road, some formerly luckless traveler again would be able to move; and a new pattern of travel would be observed although none of the travelers had changed his particular path. 当然，我们在这里其实仅仅能将他们当作幸运者。如果加油站此时转移到了一条新路上，一些一开始不够幸运的旅者将能够再次前行，此时，即使没有任何旅者改变他们特定的路线，我们也可以观察到一个新的旅行模式。The really possible paths have changed with the changing environment. 真正可能的路线随着环境的改变也已随之改变。All that is needed is a set of varied, risk-taking (adoptable) travelers. 所有这些只需要一组变量，承担风险的众多旅者。The correct direction of travel will be established. 而旅行的正确方向已经被确立了。As circumstances (economic environment) change, the analyst (economist) can select the types of participants (firms) that will now become successful; he may also be able to diagnose the conditions most conducive to a greater probability of survival. 当环境（经济环境）改变，分析者（经济学家）可以挑选出哪种类型的参与者（公司）将会成功，他也可能会推断出对于较大生存几率的来说哪些最有利的条件。.CHANCE DOES NOT IMPLY NONDIRECTED, RANDOM ALLOCATION OF RESOURCESIV.偶然性并不意味着非指导性的、随机性的资源配置These two examples do not constitute an attempt to base all analysis on adoptive models dominated by chance. 我们用生物演化和芝加哥旅者两个例子，并非是试图构造一个可以进行所有分析的由不确定性主导的（环境）采纳模型。But they do indicate that collective and individual random behavior does not per se imply a nihilistic theory incapable of yielding reliable predictions and explanations; nor does it imply a world lacking in order and apparent direction. 但是他们确实指出了集体和个体的随机行为本身意味一个“不会产出可信预测和解释”的虚无主义理论，同时这又并不意味着世界就会由此缺乏秩序和明显导向。It might, however, be argued that the facts of life deny even a substantial role to the element of chance and the associated adoption principle in the economic system. 但可争论的是，现实生活中甚至否认偶然性要素具有一个实质性作用，并且拒绝和经济系统的选择采纳原则相联系起来。For example, the long lives and disparate sizes of business firms and hereditary fortunes may seem to be reliable evidence of consistent foresighted motivation and nonrandom behavior. 例如，长寿且有差异的商业公司和世袭的财富可能看起来是可靠的“始终一致的有预见性动机和非随机性行为”的证据。 In order to demonstrate that consistent success cannot be treated as prima facie evidence against pure luck, the following chance model of Borel, the famous French mathematician, is presented. 为了初步证明这些“连续的成功”并不能被当作否定纯粹偶然性因素的证据，我们将展示一个著名法国数学家Borel的偶然性模型。Suppose two million Parisians were paired off and set to tossing coins in game of matching, each pair plays until the winner on the first toss is again brought to equality with the other player. 设想两百万巴黎人配对进行抛硬币比赛，只要当同一组的两位选手投出相同的一面，即可获得胜利。 Assuming one toss per second for each eight-hour day, at the end