Let’s pick up the observation Ashby made at the end of the last selection, regarding the job of a regulator, and continue with his text from there.
Regulation In Biological Systems
10/6.[cont.] If is a regulator, the insertion of between and lessens the variety that is transmitted from to Thus an essential function of as a regulator is that it shall block the transmission of variety from disturbance to essential variable.
Since this characteristic also implies that the regulator’s function is to block the flow of information, let us look at the thesis more closely to see whether it is reasonable.
Suppose that two water-baths are offered me, and I want to decide which to buy. I test each for a day against similar disturbances and then look at the records of the temperatures; they are as in Fig. 10/6/1.
There is no doubt that is the better; and I decide this precisely because its record gives me no information, as does about what disturbances, of heat or cold, came to it. The thermometer and water in bath have been unable, as it were, to see anything of the disturbances
- Ashby, W.R. (1956), An Introduction to Cybernetics, Chapman and Hall, London, UK. Republished by Methuen and Company, London, UK, 1964. Online.