「ARMEN A. ALCHIAN：UNCERTAINTY, EVOLUTION, AND ECONOMIC THEORY」正文
ARMEN A. ALCHIAN[4]
University of California at Los Angeles
A modification of economic analysis to incorporate incomplete information and uncertain foresight as axioms is suggested here. 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. Despite these changes, the analytical concepts usually associated with such behavior are retained because they are not dependent upon such motivation or foresight. 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.” 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. This wider applicability and the removal of the unrealistic postulates of accurate anticipations and fixed states of knowledge have provided motivation for the study.
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. 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.” 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.
This phenomenon―environmental adoption―is then fused with a type of individual motivated behavior based on the pervasiveness of uncertainty and incomplete information. 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.” A final section discusses some implications and conjectures.
Ⅰ. “PROFIT MAXIMIZATION” NOT A GUIDE TO ACTION
Current economic analysis of economic behavior relies heavily on decisions made by rational units customarily assumed to be seeking perfectly optimal situations[5]. Two criteria are well known―profit maximization and utility maximization[6]. According to these criteria, appropriate types of action are indicated by marginal or neighborhood inequalities which, if satisfied, yield an optimum. 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. 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.
Attacks on this methodology are widespread, but only one attack has been really damaging, that of G.Tintner[7]. He denies that profit maximization even makes any sense where there is uncertainty. 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. 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. Implicit in uncertainty is the consequence that these distributions of potential outcomes are overlapping[8]. 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. 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.
For example, let each of two possible choices be characterized by its subjective distribution of potential outcomes. 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. Which one is the maximum? This is a nonsensical question; but to ask for the optimum distribution is not nonsense. 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.” The maximum-profit criterion is not meaningful as a basis for selecting the action which will, in fact,