[From Rick Marken (950216.1200)]
I said:
They ought to have been "incontrovertible" [demonstrations that information
comes through the perceptual function], perhaps, but they were not; Bill
and I controverted them.
Martin Taylor (950215 11:10) reples:
No you didn't. You sidestepped them without dealing with the issues.
I assume that you are using the plural "you". If there was any "sidestepping"
done, it was done by Bill Powers, Tom Bourbon AND myself. Here, for example,
is a recent sidestep from Bill Powers (950215.1240 MST):
nobody knows how to analyze the information situation in a closed-loop
system (at least I've never seen it done), so it's a moot point anyway.
[Incidentally, Tom Bourbon has lost his connection to the Net so he can't
"sidestep" in person; but he told me to tell you that he was as convinced by
your "incontrovertible" proofs about information in perception as I was;
maybe even less so, if that's possible;-)]
The great debate about "information in perception" was, from my perspective,
about the fact that lineal, cause-effect thinking doesn't apply when dealing
with closed-loop systems. What started the debate( as I recall) was the
observation that the output of a high gain control system almost perfectly
counters the effects of disturbances to a controlled variable even though the
effects of these disturbances cannot be perceived by the control system
itself. I believe it was at this point that Martin introduced the claim that
there was information about such disturbance effects (or the disturbing
variables that produce them -- Martin was not clear at first) in the
perceptual signal.
Martin proceeded to go though some arcane mathmatical gymnastics to try to
show that lags between the effects of disturbance and outputs on perception
made it possible to detect the disturbance in the perceptual signal. Martin
was obviously making this stuff up as he went along in order to protect (for
himself) the notion that perception contains information regarding how to
respond in order to accomplish intended results -- the lineal cause-effect
approach to explaining control.
While Martin may have managed to prove to himself that there is information
that (as he now says) "comes through the perceptual function", he was not
able to prove it to Tom, Bill, myself or anyone else who has understood (or
cared about) what was going on in that discussion. Martin has managed (and
will undoubtedly continue to manage) to control his imagined version of
control system operation despite the fact that it is completely inconsistent
with the way control systems actually operate. Mazel tov;-)
While I no longer hope (or care) whether Martin ever abandons the idea that
perception "informs" a control system, I think some very useful points were
made in the discussion of information in control systems. Here are a few
that come to mind:
1) Since p = f(o + d) (perceptual signal is a function of the sum of output
and disturbance) AT ALL TIMES in a simple control task, there is no way a
control system can determine, at any instant, the extent of the contribution
of d and o to p; so there is no information about d (or o) in p.
2) The outputs of a control system depend on r-p, not p, which is why Bill
Powers (950215.1240 MST) just said:
I would say that it is through the perceptual function and the comparator
that the information needed for control is obtained.
Of course, what comes though the comparator is the error signal -- nothing
else. So the error signal could be called the "information needed for
control". There is no need for a control system to have any information in
its perceptual signal about the variables causing that signal because the
outputs of a control system are determined (in a closed loop) by the error
signal, not the perceptual signal.
3) There is nothing in the time variations in p that can be used as a basis
for separating out the effects of o and d on p. We knew this from the
math but it was also demonstated experimentally in three ways:
a) Different time variations in p result in the same output variations
when disturbance variations are the same; this is the experimental result
replicated by Chuck Tucker and reported by him in a recent post to the Net.
b) There is hardly any correlation between p and d (or between
derivatives of p and derivatives of d) at any lag between these variable.
Martin had claimed (with no data, once again; apparently just to justify
his preconceptions) that variations in p or variations in the derivative of p
could be used to infer d; they cannot.
c) No one has been able to reconstruct variations in d from variations in
p; this is what the control system would have to do if it were using
information in p about d as the means for generating o. [Martin WAS able to
reconstruct variations in d from variations in p when he was given
information about ALL parameters and functions of a control system AND it's
environment - - information that the control system itself could not possibly
have. This is the evidence that there is information about the disturbance in
perception that Martin says I refuse to accept. Of course, Tom B. and Bill P.
refuse to accept this evidence too because it is not evidence at all. Martin
has shown that, given values of p and r and k it is possible to solve for o
in an equation like o = k(r-p); in other words, Martin has provided evidence
that algebra words. If Martin had sent back variations in d when sent nothing
other than variations in p (which is what a control system does) it would
have been STRONG evidence that there is information "coming through the
perceptual function" of a control system; but he didn't.
Bill Powers (950215.1240 MST) answered Martin's points about "alerting" and
the "goals of reorganization". I want to echo Bill's suggestion to Martin
that:
Maybe you should offer an example that you think PCT can't handle without
the "alerting" hypothesis.
But, of course, that would involve presenting (yuchhh) data and I know that
Martin prefers to reason about the horse's mouth (based on "first principles")
rather than look in it.
I said:
The next step in going up a level would be to figure out WHY you have a
control system operating with the goal of keeping the cursor on the target.
Bill Powers (950215.1240 MST) --
This can too easily be taken to mean "think up a logical rationalization
or hypothesis." When you're really doing the Method, you don't have to
look for the higher-level process: it's already there and working.
Yes. What I said above is not only misleading; it is wrong. It was based on
my own misunderstanding of the method of levels. Your comments have helped me
understand the method better.
In fact, when I do the method of levels I never really figure out "why" I
want something (like "getting Martin to see things my way" -- possibly a bad
example;-)) That would be rationalization -- controlling perceptions in order
to "make sense" of other controlling I am doing.
I would describe what I am doing when I "go up a level" as something like
"dissociation"; I become conscious of something I am doing as though "someone
else" were doing it.
It's a lot easier for me to "dissociate" myself in this way from a behavior
like the typing I am doing with my hands than from a behavior like the
"convincing people that PCT is right" that I am also doing with my hands (at
the same time). Both these behaviors are examples of controlling and I can
become conscious of both as though they were being done by "someone else"; I
can dissociate myself from them. This is what I think of as "going up a
level". Does it seem that what I'm doing when I "go up a level" is the same
as what you're doing?
Best
Rick