International Encyclopedia of Systems and Cybernetics

"Any system whose parts have many equilibria and that has been formed by taking parts at random and joined at random" (W.R. ASHBY 1960, p.173).

What ASHBY has in mind are systems whose parts are "…assured to be state-determined, and thus to have (in themselves) no randomness at alt' (Ibid).

Some examples are von FOERSTER's small magnets in his famous "order from noise" experiment, or better still, neurons – natural or artificial.

What ASHBY wants to study is the way such elements, when joined, start to organize themselves spontaneously.

He sums up the result of such a process in the following way: "The polystable system, if composed of parts whose states of equilibrium are distributed independently of the states of their inputs, goes to a final equilibrium in a way that depends much on the amount of functional connection" (p.178).

He adds: "When the connection is rich, the line of behavior tends to be complex and, if n is large, exceedingly long; so the whole tends to take an exceedingly long time to come to equilibrium" (Ibid). As possible examples (admittedly hypothetical) we may consider any complex society, like neurons in the brain or people with diversified roles in a numerous human organization.

ASHBY completes his comment saying: "When the connection is poor (either by few primary joins or by many constancies in the parts), the line of behavior tends to be short, so that the whole arrives at a state of equilibrium soon" (Ibid).

ASHBY's own quite simple homeostat is a good example.