People often interpret *Ashby’s Law* (after W. Ross Ashby) as if the *system*'s internal states must have the ***same level of variety*** as its *environment* in order to survive, which implies that the system should be able to *respond* (react) to every little disturbance from the environment.
This is not completely true because, on the lowest, #regulation, level, the system blocks #variety from an (environmental) #disturbance reaching the (internal, system protected) #EssentialVariables in two ways:
1️⃣ #Passive isolation (sheltering) from most environmental disturbances, and
2️⃣ #Active reaction to (parring with) the remaining disturbance that managed to *break through* this passive protection.
from "Intro to #Cybernetics"
http://pespmc1.vub.ac.be/ASHBBOOK.html
Ashby's principle of requisite #variety states, in fact, that the variety of the #controlling system must be large at least as the variety of the #controlled system .
As an *external* #observer can never have the full picture of the *internal* variety of states the controlled system can find itself in, it is obvious that, for control to be #effective, the controller must be an integral part of the same self-organized (controlled) #system.
