Re: requisite variety/... systems concepts

Bruce Edmonds (B.Edmonds@MMU.AC.UK)
Thu, 5 Oct 1995 10:09:21 GMT


Late respons...

> There were two derivations given by Ross Ashby for the law of requisite
> variety: !) (the
> 1) It can be derived formally from games theory where it
> amounts to the statement that to draw you have to have at least as great a
> variety of moves as your opponent has. se ashby Intro to Cybernetics
> for the automaton/game-theory (sort of a-priori theoretical derivation).
> His other derivation is more empirically substantive and it shows that
> the Law of requisite variety ( Control variety must equal or exceed
> disturbance variety (at each emergent level gmb.) for control=steering
> to be achieved/maintained). or poetically "Only variety can destroy
> variety!"

I have often wondered how this could be applied for organisms in
ecosystems. From the explanation above I now understand I just missed
the point.
My thoughts were that an organism does not need to have a high
variety of resaponses to deal with a high variety of threats to his
life [including the fact that he needs to do a lot of things to keep
his life, like finding food, etc.].
An organism can simply have a respons to threats being : 'hide'. He
can control a high variety of these threats by a low variety of
responses.
If I understand it right this means that his is in controle of his
survival, but is not controling the threats as in steering them. So
it seems I confused two meanings of the word controle.

Could that be true?

Theories come and go, the frog stays [F. Jacob]
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