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Date:         Mon, 21 Dec 1992 14:30:34 -0800
From:         Marken@COURIER4.AERO.ORG
Subject:      Re: Rick on (off) Shannon

[From Rick Marken (921221 1300)

Martin Taylor (921216 17:40) --

>The argument was roughly (as seen from my side): if there is an intrinsic
>variable (i.e. a variable outside the main hierarchy, in a Bill-P-type
>reorganization hierarchy) with a reference level R and perceived level P,
>giving error E, then I assert that the controlled variable is P.  Rick
>asserts that it is d(E^^2)/dt.

If this were the argument then there would have been no argument.
Remember, I?m the guy who posted that little proof that the
ERROR VARIABLE IN A CONTROL LOOP is not controlled.
Why the hell would I have argued that error IS controlled?
Unfortunately, I have saved none of our private  posts but  I
remember the argument quite differently  -- I thought that
you were saying that intrinsic error (or some transform thereof)
was controlled in reorganization.  Now you say it the perception
of the intrinsic variable that is controlled -- which (of course) is
correct and I agree.

If you have saved the private posts, Martin, then you could post
them and clear this all up. But even without them it is clear from
my post to the net that I NEVER suggested that  ?d(E^^2)? was
controlled -- where E (in your comment above) is the error in
the system controlling the intrinsic variable, P. When I said that
d(e^2) is controlled, I made it quite clear that this was a
perceptual variable -- representing perception of error in
OTHER control systems. And I never made a big deal about
what the form of the function was -- it?s a perceptual function
and determining it is best left to research and modelling.

>Now what might be an intrinsic variable.  I used blood CO2 concentration,
>but I'm quite happy with overall error in the main hierarchy.  But if
>overall error is to be used, Rick's formula won't work.

Well, I won?t conceed that until I see it modelleed. But
I never made an issue of what the damn function is that
transforms overall error into a perceptual measure of error --
I was just saying that ?error in the main hierarchy? can be
a controlled intrinsic variable. Apparently you are happy
with that; if you had written the above paragraph N posts
ago we could have saved all this useless blather.

> Rick was talking
>about error in the hierarchy AS an intrinsic variable, but using an
>expression that couldn't work, whereas when I used the word "error" I
>was referring to error IN an intrinsic variable (which might well be
>overall error magnitude in the main hierarchy).

Well, then why did you just now (see above) say  ?Rick
asserts that it is d(E^^2)/dt.? that is controlled; where E
is  error in the  control system controlling the intrinsic
variable (according to your notation)? If you don?t
want to have confusion, don?t be confusing.

I find this little misunderstanding (if that?s what it was)
particularly annoying  because it led Bill Powers to write:

>I think I have to side with Martin Taylor on this one, Rick. In a
>simple reorganizing model, e^2 might be a suitable driving signal
>for the rate of reorganization. But that isn't the controlled
>variable. It's the error signal.

Again -- I?M THE ONE WHO WROTE THE DAMNED PROOF that
error is not controlled; of course e^2 is not controlled -- unless it
is PERCEIVED by another control system which can act in ways that
have systematic effects on that perception. Why in the hell would any-
one imagine that I was arguing that an error signal in a control loop is
controlled??? How could you imagine that this was my argument,
Martin????

Martin Taylor  (921217 10:40)

>I really can't let Rick's latest non-sequitur go unchallenged:

>Every piece of the loop is constrained by Shannon's observations/theorems.
>If (like Rick) you don't understand them, you are doomed not to uinderstand
>PCT.

Well, you got me there Martin (I think I understand Shannon?s
observations/theorems ok, though not nearly as well as you). But since
you understand PCT so well (thanks to your understanding
of information theory) why haven?t I seen any of your PCT research or
modelling work in the last decade or so,while I?ve been working on PCT?
About the only work I ever found was done by Bill Powers. I did find
some stuff by Carver/Scheier types who didn?t know the difference between
a controlled variable and a reference signal. I also saw lots of tracking
studies by people who?s goal was to figure out how target inputs cause
response outputs. But I never found any research (other  than Bill?s) that
was based on a deep understanding (like yours) of PCT. In the last  few
years I?ve seen some great stuff done by people like Tom Bourbon (and
his students), Clark McPhail, and Chuck Tucker and a couple others.
But I never ran across anything of yours. Since you REALLY understand
PCT  I bet your stuff is great. I?d really like to see it; especially the
stuff
that shows how important information theory is for doing PCT research
and modelling.

Martin, I count a statement like this:

>If (like Rick) you don't understand them, you are doomed not to
>uinderstand PCT.

as a personal insult. It is a disturbance to the level at which I like
to maintain the perception of my own self esteem. I?m sure you
will say that it was not meant as an personal attack -- and I?m prepared
to believe that; but I don?t really care -- a disturbance is a disturbance,
regarless of the intent of the source; so here is a little compensating
action (in lieu of going up a level):

If (like Martin) you don't undertand PCT, DON'T TRY TO
TEACH IT. Those of us who do understand it  -- and
have done the grunt work necessary to grasp the
fundementals --  find condescending tutorials on PCT
to be cloying.

Best regards

Rick (what else would you expect from a loose canon?)
Marken
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