[From Bill Powers (950801.0810 MDT)]
Bill Leach (950801.00:20 U.S. Eastern Time Zone) --
All your other friends are sorry about your loss, Bill.
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Rick Marken (950731.2130) --
Good idea on starting an applications thread. Joel Judd's post fits
right in: what are the teachers being taught? And in management
applications, what do managers _now_ believe about how people work? As
always, it's not teaching PCT that's the problem. It's trying to undo
the teaching that's already been done.
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Avery Andrews (080195:1505 OZ time)--
Something that won't make anybody happy, but should probably be
known about...
> By adaptive behavior we usually mean behavior that adapts to the
>varying environmental structures that an individual encounters.
>Thus, to understand adaptive, environmentally embedded behavior,
>we must understand not only an organism's behavior-generating
>system, but also the structure of the organism's environment.
Odd, isn't it? This sounds like a perfectly reasonable PCT proposition:
any model of the organism must include a model of the local environment.
But somehow just leaving out any mention of control makes all the
difference.
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Oded Maler (950801)--
(Trying to summarize Bills and Martin) The difference between
control and equilibrium is that in equilibrium the relation between
the deviation from the reference, and the correction is more
"direct" ("physical", "energetic"), while in control it is mediated
by "information" (a low-energy process that senses the deviation
and responds by activating some large energy reservoirs).
That's the basic idea. The informational processes create cause-effect
relationships among physical variables that would not exist without
them, and that even appear to go contrary to physical laws.
How about an example of something which seems (to me) to fall
between the two: Maxwell's flyball governor?
The flyball governor is still an example of a system that draws on an
energy supply to create an equilibrium condition where one would not
naturally exist. The flyball arrangement itself is simply a way to
convert the rotary velocity of an engine into a steady linear
displacement (the part of the governor that rises and falls as speed
changes). The power amplification arises from the way the flyball
operates a lever that lets more or less steam into the engine. The lever
and valve are the low-energy part of the process; a large flow of steam
energy is varied by a small low-energy movement of the lever.
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Best to all,
Bill P.