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Date:         Sat, 15 Aug 1992 09:02:04 -0600
From:         "William T. Powers" <POWERS_W%FLC@VAXF.COLORADO.EDU>
Subject:      Amplification: organism vs environment
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[From Bill Powers (920815.0930)]

Martin Taylor (920815) --

Rick Marken says:
>>The short
>>answer is "because the organism amplifies, the environment dampens".

and Martin replies

>Not always true, and certainly not true of that part of the environment
>that contains control systems. Not true in sensitive parts of the
>environment that don't (e.g. bifurcation points, such as things >balanced
on table edges). Sufficiently often true that it is a >beguiling temptation
to take it as truth.

When control systems come in contact, that's a rather special case.
Generally they avoid doing so in a way that pits their outputs directly
against each other. The reason is that they're BOTH high-gain systems. This
doesn't negate Rick's statement. The non-controlling environment is not, in
general, a high-gain system.

The rest of the environment contains so few instances of significant
amplification that they're pretty unusual. It's hard to think of a case in
which the gain of a human controller isn't higher than that of the
environment by a wide margin. When a car moves along the crown of a
cambered road, the car is unstable about a knife-edge line along the crown;
its path bifurcates. But a human driver has no problem keeping the car
centered on the crown within a small range. The book teetering on the edge
of the table is easily kept from falling by a person who lays a finger
lightly on it. Even ten-year-olds have no problem with balancing a
broomstick on end. To find instances of significant amplification in the
physical world, you have to talk about explosions and things that snap from
one state to another faster than a human control system can control them
between states. There aren't just a heck of a lot of such phenomena. Most
of those that do occur are man-made (like explosions and switches).

As to the mirror diagram, it is an epistemological tool. This diagram could
be expanded to show the hypothetical world of physical reality between the
two mirroring hierarchies. When we analyze control processes, that is
essentially what we do: we apply physical analysis to our experiences and
attribute them to physical properties of the world between the systems.
That's the only practical thing to do. The mirror diagram itself exists
only in the perception of the beholder; it's an hypothesis about the
relationship between two control hierarchies, as envisioned by one of them.
To continue this process of abstraction is to head for a state of mute
contemplation. I think we have to admit that it's all hypothetical, and try
to formulate our hypotheses in the way that's most tractable both for
theorizing and for experimenting. My formulation puts a physical world
running by physical laws between the organisms which are control systems
running by closed-loop laws. That seems to work passably well. And in that
formulation, Rick's comment is right nearly all of the time, if you
understand "environment" to mean the milieu between control systems.
----------------------------------------------------------------------
Best,

Bill P.
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU