In "Heart of Enterprise" a companion volume to "Brain...", Beer applies
Ashby's concept of (Requisite)
Variety: the number of possible states of a system or of an element of the system. There are two aphorisms that permit observers to calculate Variety; four Principles of Organization; the Recursive System Theorem; three Axioms of Management and a Law of Cohesion. These rules ensure the Requisite Variety condition is satisfied, in effect that resources are matched to requirement.
Regulatory aphorisms These aphorisms are: • It is not necessary to enter the
black box to understand the nature of the function it performs. • It is not necessary to enter the black box to calculate the variety that it potentially may generate.
Principles of organization (Principles are 'primary sources of particular outcome') These principles are: • Managerial, operational and environmental varieties diffusing through an institutional system, tend to equate; they should be
designed to do so with minimum damage to people and cost. • The four directional channels carrying information between the management unit, the operation, and the environment must each have a higher capacity to transmit a given amount of information relevant to variety selection in a given time than the originating subsystem has to generate it in that time. • Wherever the information carried on a channel capable of distinguishing a given variety crosses a boundary, it undergoes
transduction (converting energy from one form to another); the variety of the transducer must be at least equivalent to the variety of the channel. • The operation of the first three principles must be cyclically maintained without delays.
Recursive system theorem This theorem states: • In a
recursive organizational structure any viable system contains, and is contained in, a viable system. • Society itself can be seen as a system of
recursion. In this case, recursion refers to systems that are nested within other systems.
Axioms (Axioms are statements 'worthy of belief') These axioms are: • The sum of horizontal variety disposed by
n operational elements (systems one) equals the sum of the vertical variety disposed by the six vertical components of corporate cohesion. (The six are from Environment, System Three*, the System Ones, System Two, System Three and Algedonic alerts.) • The variety disposed by System Three resulting from the operation of the First Axiom equals the variety disposed by System Four. • The variety disposed by System Five equals the residual variety generated by the operation of the Second Axiom.
The law of cohesion for multiple recursions of the viable system This law ('something invariant in nature') states: • The System One variety accessible to System Three of recursion
x equals the variety disposed by the sum of the metasystems of recursion
y for every recursive pair. ==Measuring performance==