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Law of Requisite Constraint

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As is well known, in order for there to be a proper coordination of actions to perception the system must be able to select the correct choice. The ability of the system to avoid incorrect or unviable choices is a constraint on the behavior of the control system. If no such constraint existed, the system would have to try out actions blindly, and the larger the variety of perturbations, the smaller the probability that those actions would turn out to be adequate.

Thus all viable modeling and aniticipatory control requires an intermediate quantity of variety: enough to satisfy the LRV that it is possible to represent all necessary control systems; but not too much to violate the Law of Requisite Constraint and leave the system with insufficient "knowledge" about its environment.

This intermediary balance between freedom and constraint in viable systems has long been noted in information theory \cite{ZWM84a}. This can be measured in the intermediate entropy values that can be measured in symbol systems such as linguistic texts and chromosomes.

Copyright© 1992 Principia Cybernetica - Referencing this page

C. Joslyn,

Jan 1992


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