1903–1972 · psychiatrist and cybernetician, Gloucester, Bristol, Illinois

illiam Ross Ashby trained in medicine and worked for most of his career as a psychiatrist and hospital researcher in England, latterly as director of the Burden Neurological Institute in Bristol, before moving to the University of Illinois in 1961.

what he did

From 1940 he argued that adaptive behaviour is a kind of stability, and in 1948 he built the homeostat to show it. Design for a Brain (Ashby, 1952) worked the idea out as ultrastability. An Introduction to Cybernetics (Ashby, 1956), written as a textbook, states the law of requisite variety: only variety in a regulator can absorb variety in what disturbs it [paraphrase, not a quotation]. With Roger Conant he later proved the good regulator theorem (Conant & Ashby, 1970).

what is argued about

Whether his machines modelled brains or only demonstrated principles; and whether the good regulator theorem says as much as its slogan. Pickering (2010) makes the case for Ashby as the author of a non-representational picture of mind [paraphrase, not a quotation].

why he is here

Ashby asked the question that every control and learning system faces: what must a regulator contain to keep up with its world? It returns in specification gaming and automation bias.

in the tour: the room called "Governors and feedback" has a placard called "Ashby’s law of requisite variety" ···

Primary works and sources

1. Ashby (1940). Adaptiveness and Equilibrium. Journal of Mental Science. doi:10.1192/bjp.86.362.478
2. Ashby (1952). Design for a Brain. London: Chapman & Hall. The 1954 Wiley printing is scanned at the Internet Archive. archive.org/details/designforbrain00ashb
3. Ashby (1956). An Introduction to Cybernetics. London: Chapman & Hall; New York: Wiley. Scanned at the Internet Archive. archive.org/details/introductiontocy00ashb
4. Conant & Ashby (1970). Every good regulator of a system must be a model of that system. International Journal of Systems Science. doi:10.1080/00207727008920220
5. Pickering (2010). The Cybernetic Brain: Sketches of Another Future. Chicago: University of Chicago Press.

see also

	the homeostat — the machine
	timeline: cybernetics
	Norbert Wiener — who named the field