---
title: "Variety and regulation"
description: "Variety as Beer's measure of complexity, Ashby's Law, and designed attenuation/amplification."
url: "https://wiki.cybernetic-futures.org/pure-vsm/concepts/variety-and-regulation"
modified: "2026-11-12T15:26:25.983Z"
language: "en"
site: "Cybernetic Futures"
---

# 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. [Pure VSM — Overview](https://wiki.cybernetic-futures.org/pure-vsm/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](https://wiki.cybernetic-futures.org/pure-vsm/concepts/principles-and-axioms-of-organization) designs the three varieties to equate (HOE 1979: 97, 565). [System Five](https://wiki.cybernetic-futures.org/pure-vsm/concepts/system-five) administers Ashby's Law (HOE 1979: 263). [Algedonic signal](https://wiki.cybernetic-futures.org/pure-vsm/concepts/algedonic-signal): "the biggest variety reducer of them all" (BOTF 1981: 233). Counting is observer-relative ([Observer and recognition](https://wiki.cybernetic-futures.org/pure-vsm/concepts/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.

## Punch and Judy

Punch and Judy (Mathis and Heath, v0.5.0 draft) argues that the form of Ashby's law reproduced here under Ashby's name is Beer's compression — with Beer's verb it instructs a designer, with Ashby's it states a bound — and that the good regulator theorem does not prove what it is cited for, a matter the manuscript calls corrected footnotes rather than a new experiment (Ch 3). It reports Galbraith rederiving the same attenuation/amplification design space from Boeing field data without cybernetics, and records Beer conceding that variety cannot be counted absolutely, only matched by state generators (Ch 12). Chapter 25's charge — that regulatory loss sits at the boundary crossing rather than the channel, and that this principle has never been measured — is marked by the authors as unoperationalized, its coding study proposed and not run.

## 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](https://wiki.cybernetic-futures.org/pure-vsm/entities/stafford-beer) · [Viable System Model](https://wiki.cybernetic-futures.org/pure-vsm/entities/viable-system-model) · [Management Science (1967)](https://wiki.cybernetic-futures.org/pure-vsm/entities/management-science-1967) · [Part I — Foundations](https://wiki.cybernetic-futures.org/pure-vsm/part-01-foundations) · [Part V — Method and epistemology](https://wiki.cybernetic-futures.org/pure-vsm/part-05-method-and-epistemology) · [Punch and Judy — Overview](https://wiki.cybernetic-futures.org/punch-and-judy/overview)