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UNCERTAINTY, EVOLUTION, AND ECONOMIC THEORY 不确定性、进化和经济理论

ARMEN A. ALCHIAN

University of California at Los Angeles

A 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 kno

wledge 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 phenomenon—environmental adoption—is 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。

Ⅰ. “PROFIT MAXIMIZATION” NOT A GUIDE TO ACTION I.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 known—profit 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。Tintner’s 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

profits—there 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

profits—a 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‖