Variety and regulation

Variety is “the measure of complexity” (HOE 1979: 45): possible states of a system, relative to observer and purpose (DTS 1985: 98). Control is Ashby’s Law. overview Draft 0.8 — not project canon.

What Beer says

“roughly defined as the possible number of distinguishable states in a situation”; “the control must be capable of generating as much “variety” as the situation to be controlled” (MS 1967: 37; similarly 149). “Variety is the number of possible states of the system” (DTS 1985: 98); DF: “variety means the number of possible states” (DF 1974, Lecture 1). Glossary: “the total number of possible states of a system, or of an element of a system” (BOTF 1981: 403). “variety is the very stuff and substance of modern management” (BOTF 1981: 229).

Ashby’s Law: “control can be obtained only if the variety of the controller (and in this case of all the parts of the controller) is at least as great as the variety of the situation to be controlled” (BOTF 1981: 41). HOE: “VARIETY ABSORBS VARIETY” (HOE 1979: 86). Chile: “Only variety can absorb variety” by expanding regulatory variety or curbing evolutionary learning (BOTF 1981: 308).

Variety engineering: “the manipulation of varieties by design” (DTS 1985: 26). Attenuation: high variety “is necessarily cut down, or attenuated, to the number of possible states that the receiving entity can actually handle” (DTS 1985: 23). Amplification is not automatic from information-gathering (DTS 1985: 25). “it is management’s job to DESIGN the necessary amplifiers and attenuators” (HOE 1979: 97).

Where it sits in the model

First Principle of principles-and-axioms-of-organization designs the three varieties to equate (HOE 1979: 97, 565). system-five administers Ashby’s Law (HOE 1979: 263). algedonic-signal: “the biggest variety reducer of them all” (BOTF 1981: 233). Counting is observer-relative (observer-and-recognition).

Textual notes

MS “roughly”/“distinguishable” (MS 1967: 37) vs BOTF 1981: 403 vs DTS 1985: 98 vs HOE 1979: 45. BOTF/HOE name Ashby; MS 1967: 37 does not.

Open points

MS 1967: 37, 149 not rechecked on page images (ch. 2, 27). DF 1974 transcript, no print pagination. Conant–Ashby article title unchecked (not a Beer quotation).

Related

stafford-beer · viable-system-model · management-science-1967 · pure-vsm-part-i-foundations · pure-vsm-part-v-method-and-epistemology