ゆらぎ・あそび・ゆとり : 複雑系の三つの視点

抄録

Market economy is an object which can only be well understood when viewed as a complex system.The agents are subjected to three limits:(1)bounded sight, (2)bounded rationality, and (3)bounded activity.They have no ability for a full adjustment which is assumed in the walrassian groping processes.The complexity of the system remains far beyond the human capacity to see, think, and act.An agent behaves by a rule of thumb, a routine which has been selected through a number of trials of success and failure.In order that this selection be meaningful, the economy itself must have certain characteristics.First, the economic processes must be stationary even though they inevitably involve fluctuations.Second, the system is to be divided into a large number of small parts and each part must be loosely connected with others.This looseness is only possible when the system functions with play.An agent can then isolate a subsystem which he may partially control.Adjustments and controls are always imperfect.Agents may make errors.If the system is to subsist, however, the agents cannot die out all in once and so, thirdly, they must have a sufficient marge of viability above the death-life break-even point.