Controling observables (was Re:... long live William T. Powers)

[Eetu
Pikkarainen 2017-06-12]

Â

···
                      EP: The

issue is ONLY that we do NOT control anything
in the environment but only our own
perceptions - even though the control is
realized by affecting the environment.

Â

              RM: This is simply not true. See my

recent post to Martin. I’ll just repeat my last point:
If people controlled only their perceptions then there
would be no way for anyone other than the person doing
the controlling to know this.

Â

                EP: I think you

partly replied on behalf of in your message
[From Rick Marken
(2017.06.11.1640)] but only partly. You wrote:

Â

                “a controlled

perception is an inference based on
observation of the fact that certain variables in
what is perceived by an observer as the subject’s
environment are controlled (maintained in reference
states, protected from disturbance).�

Â

                This means that

an observer sees something special happen in the
environment and from that s/he
infers that the subject is controlling some
perception. As part of that inference the observer
can do tests and try to disturb the subject’s
controlling. What the observer is seeing is not
control, but stabilization, see below…

Â

                      EP:

Question is about the definition of control in
PCT.Â

Â

              RM: The definition of control in

PCT is completely in terms of observable variables.

              It is an "objective" definition in

the sense that others besides the observer can confirm
the observation. The definition of control in PCT is:
maintenance of a variable in a reference state,
protected from disturbance. “Perception” is not part
of this definition; perception is a component of the
theory that accounts for this objectively observable
phenomenon.Â

Â

                EP: Perception

may not be a part of the definition, but the
reference is. Like perception, also the reference is
only inside the subject / organism. It is not
principally unobservable, but at the current and
near future state of neurology it is not possible to
measure the reference value of the subject. So the
definition of control (in PCT) cannot be defined
completely in terms of
observable variables.

Â

                EP: When you see

(the fact) that something is (in a certain way and
conditions) stabilized in the environment of the
subject, you can infer from that to (the fact of)
control. It is like all science a hypothetical and
fallible inference, but by experience a more
reliable inference than many everyday alternatives.
That is just the glory of science: you can know
something what you have not (immediately) perceived.

Â

[From Rick Marken (2017.06.13.0925)]

image364.jpg

image365.png

···

Martin Taylor (2017.05.12.13.14)–

                      EP: The

issue is ONLY that we do NOT control anything
in the environment but only our own
perceptions - even though the control is
realized by affecting the environment.

              RM: This is simply not true. See my

recent post to Martin. I’ll just repeat my last point:
If people controlled only their perceptions then there
would be no way for anyone other than the person doing
the controlling to know this.Â

MT: The truth of that depends entirely on your definition of control. If

the definition of control requires that there be an observer, the
underlying philosophy is one that says definitively: "If a tree
falls in the forest and no organism is around to hear it, it DOES
NOT make any sound."Â

RM: The definition of control doesn’t require an observer. It is simply a description of something that has been observed (by Powers) and that, then, can be observed by anyone willing to look. Like the tree in the forest, it exists whether or not anyone is there to observe it.Â

MT: As I think of the way the world works, control happens (or does not

happen) whether or not there is an external
Experimenter/Analyst/Observer available in the neighbourhood to
assess the environmental dynamics associated with it.

 RM: Clearly, I think of it that way too.Â

MT:.. From your quote above and from your other writing, you

think control does not exist in the world outside the Observer.

RM: What I actually think is that control exists in the world outside the observer (and controller) as controlled aspects of the environment, which are referred to as controlled variables in PCT. The explanation of control exists inside the controller (and inside the observer since the observer is a controller too); the explanation is “control of a perceptual signal that corresponds to the aspect of the environment that is seen to be controlled”.

RM: When I said “If people controlled only their perceptions then there would be no way for anyone other than the person doing the controlling to know this” I was responding to the idea that it is only the perceptual signal that is controlled by a control system. If this were actually true then there would clearly be no way for anyone (not even the person doing the controlling) to know that controlling was going on and no science of living control systems would exist. It’s observers, like Bill Powers, who do the science of living control systems; and they can do this science because they can see, using their own or artificial perceptual systems, that living organisms are controlling aspects of their environment; these observers can see controlled variables. Here’s how Bill put it in a post from 1999:

[From Bill Powers (990331.0033 MST)]Â

"The CV" is the
observer’s perception
. However, if the observer happens to be using a perceptual system
closely similar to that in the behaving system, it is possible for the
observer’s perception to covary with the behaving system’s perception. Then**the observer will see that the CV is **protected from disturbances by the
actions of the behaving system
, and the CV will pass all the parts of the
Test. [Emphasis mine – RM]

RM: The first emphasized statement says that a CV (controlled variable) is an objective phenomenon inasmuch as it can be perceived by an observer, a fact that makes PCT science possible. The next part of this quote just says that if the observer’s perceptual system is similar to that of the behaving system then the observer can monitor the behavior of the CV sans instruments, as is the case in the “coin game”. Of course, this implies that if the observer’s perceptual system differs from that of behaving system (as is the case when a human studying the navigational behavior of a bat) artificial perceptual systems are needed to monitor the CV.Â

RM: The next emphasized section just says if the observer can monitor the behavior of the CV with their own perceptual system they will see that the CV is being protected from disturbances by the actions of the system. [Disclaimer: I cannot be held responsible for any heads that explode upon reading this quote from Bill Powers.]Â

MT:... As several of us have mentioned, not only recently but over

the years, no reference state can be observed in the environment.

RM: And several of you have been as wrong about this as about perceptions being the only thing that is controlled. Since CVs are objectively observable their reference states are also observable. Indeed, what the observer sees as the behavior of the CV is the behavior of the reference state of the CV. What is not seen is the reference signal, which is the theoretical explanation of the observed behavior of the CV. And if you don’t believe me about this (which I’m sure you don’t and probably never will) here is the emmis from Powers’ “Cybernetic Model for Research in Human Development”, reprinted in LCS:


Richard S. MarkenÂ

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
                --Antoine de Saint-Exupery

RM: The “variable” referred to here is, of course, the CV. So Reference states of CVs exist as observable phenomena. Indeed, they are the raison d’etre for PCT. PCT is the theory that Bill developed to explain the existence of these reference states, as Bill goes on to note here in that same paper [NB: At the time this was written PCT was simply called “control theory”]:Â

RM: So there you have it, whether you want it or not.Â

BestÂ

Rick

[From Kent McClelland 2017.06.16.1600]

I’m struck by Rick Marken’s contention " that ‘reference state’ refers to the value of an observable variable (like the position of the controlled avatar in the Mind Reading demo) while ‘the value of the reference
signal’ refers to the value of the theoretical entity that accounts for the reference state of the observed variable.â€? (2017.06.15.0925)

Whatever labels Bill Powers once used in one of his papers, I find it confusing to apply the same label—“reference ?—to the state of an observed environmentall variable as to the unobservable variable in the theoretical process
of control that, according to advocates of PCT, can account for the state of the observed variable. Calling them both by the same name leads to confusion, I think, because it’s easy to equate one with the other, and they need to be kept sharply distinct.

To make my point, I’d like to direct attention back to the demo Martin described in his post yesterday ( 2017.06.15.13.29), because it seems to me that
Rick didn’t come grips with it in his reply (2017.06.16.1000).

Here’s the demo as Martin described it:

Imagine that the following is one frame from a compensatory tracking study, in which the subject is influencing the lateral position of
the “o” cursor. I have put markers on the guide lines to serve as a ruler (in practice the computer would do the measurement internally).

`----|----|----|----|----|

   o

----|----|----|----|----|

5   10   15   20   25

` Can you see in that environment the current location of the “o” cursor? I suspect that you can, and would say that the “o” is at location 8. What is the location of
the reference, which you say is similarly observable in the environment? You must be able to see it, but I can’t.

Some empty space deliberately left here while you think about whether you perceive the environmental reference location for the “o” in the same way as you perceive the current
location of the “o”.

.

.

.

.

[I’ve snipped out a bunch of identical lines here.]

.

.

Here are a few more positions of the cursor in some well separated sample frames:

`----|----|----|----|----|

    o

----|----|----|----|----|

5   10   15   20   25

`

`----|----|----|----|----|

     o

----|----|----|----|----|

5   10   15   20   25

`

`----|----|----|----|----|

    o

----|----|----|----|----|

5   10   15   20   25`

`----|----|----|----|----|

     o

----|----|----|----|----|

5   10   15   20   25

``----|----|----|----|----|

   o

----|----|----|----|----|

5   10   15   20   25

` Knowing that the perceived location of the “o” is being controlled, I can now infer that if the reference value has been the same through all the frames, its value
must be somewhere near 9. But I still can’t see it directly, as you say you can. Maybe I need special perception training to see it?

When Martin tells us that the inference that the reference value must be somewhere around 9, he tacitly equates the theoretical entity inside the subject with the observed state of the cursor, and the use of the word “reference� to label both of these things
invites him to do so. Similarly, Rick’s argument that control is an observable phenomenon also depends on equating these two things.

But although the theoretical entity and the state of the observed variable may be correlated with each other (and strongly correlated if control is good), the two are quite distinct, and it makes no sense to me to call them by the same name.

Imagine in Martin’s thought experiment that there is a large nearly constant disturbance, unseen by the observer, which in the absence of any action by the subject would create a substantial deflection of the cursor from left to right. You might
think of it as a strong wind constantly blowing from west to east. In this case, the reference value intended by the subject might be something distinctly different from 9, say 5, but because control is never perfect, the cursor ends up hovering right around
9 despite the best efforts of the subject to keep it at 5.

I just did a run of a simulated control system with a gain of 10 (slowing factor 0.0012), a reference value of 5, and a step-function disturbance of 40. Once the curve for the observable variable (call it the cursor) had settled down, its value
was 9.10. (Since the graph of results from this simulation is really boring, I won’t bother to reproduce it.)

In my scenario, the best inference an observer of Martin’s experiment could make is that the reference value for the subject’s control of the perceptual variable is 9, but we know from our “analyst’s perspectiveâ€? that it’s really 5. Thus, the
observed state of the environmental variable is NOT the intended reference value.

I would agree with Martin’s side of this argument. Even if an observed variable is apparently under control, what you can observe is not necessarily the intended reference value.

Of course, my perspective on all this comes from thinking and writing about collective control, where the observed state of an environmental variable being acted upon by multiple control systems with different references will end up conforming
to a virtual reference value that may be sharply different from what any of the individual actors intended.

Best to all,

Kent

···

On Thu, Jun 15, 2017 at 11:20 PM, Bill Leach wrleach@cableone.net wrote:

BL: Rick, I suggest that you re-read what Martin actually said. He did not say impossible period.

RM: Yes, I know. I guess I just get frustrated by the fact that the only thing that ever gets discussed about the TCV on CSGNet is how it (supposedly) can’t be done in this or that situation. If CSGNet is really supposed to be a place
where, as Martin says, “advances and lacunae in Perceptual Control Theory can be discussed in ways that conform to normal science” then, since the TCV is the basic methodology of PCT science, it seems to me that discussions of the TCV should be about how it
can be done, not how it can’t.

MT: … it may be extremely difficult or even impossible for an external observer to determine whether a control system is acting if the reference value is changing as unpredictably as is the disturbance or more so (PCT language)
and the observer can see only the PCT “input”.

RM: I don’t believe that that’s true. In my Mind Reading demo, for example, the computer is able to “read the mind” – that is, determine the controlled variable – of a person who is varying the reference for the state of the controlled variable
at least as unpredictably as the disturbances to that variable (which are sine waves and, thus, quite predictable).

[From Rick Marken (2016.06.16.1730)]

Kent McClelland (2017.06.16.1600)--
KM: I’m struck by Rick Marken’s contention "that 'reference state' refers to the value of an observable variable (like the position of the controlled avatar in the Mind Reading demo) while 'the value of the reference signal' refers to the value of the theoretical entity that accounts for the reference state of the observed variable.â€? (2017.06.15.0925)

RM: I hope my post [From Rick Marken (2016.06.16.1620)] in the "Environmental Reference?" thread clears things up for you. If not, feel free to ask (or tell) me about it.Â
BestÂ
Rick
 >

Whatever labels Bill Powers once used in one of his papers, I find it confusing to apply the same label—â“referenceâ€?—to the state of an observed environmental variable as to the unobservable variable in the theoretical process of control that, according to advocates of PCT, can account for the state of the observed variable. Calling them both by the same name leads to confusion, I think, because it’s easy to equate one with the other, and they need to be kept sharply distinct.Â
To make my point, I’d like to direct attention back to the demo Martin described in his post yesterday (2017.06.15.13.29), because it seems to me that Rick didn’t come grips with it in his reply (2017.06.16.1000).Â
Here’s the demo as Martin described it:Â

Imagine that the following is one frame from a compensatory tracking study, in which the subject is influencing the lateral position of the "o" cursor. I have put markers on the guide lines to serve as a ruler (in practice the computer would do the measurement internally).

----|----|----|----|----|
      o
----|----|----|----|----|
   5  10  15  20  25

Can you see in that environment the current location of the "o" cursor? I suspect that you can, and would say that the "o" is at location 8. What is the location of the reference, which you say is similarly observable in the environment? You must be able to see it, but I can't.

Some empty space deliberately left here while you think about whether you perceive the environmental reference location for the "o" in the same way as you perceive the current location of the "o".
.
.
.
.

[I’ve snipped out a bunch of identical lines here.]

.
.

Here are a few more positions of the cursor in some well separated sample frames:

----|----|----|----|----|
       o
----|----|----|----|----|
   5  10  15  20  25

----|----|----|----|----|
       o
----|----|----|----|----|
   5  10  15  20  25

----|----|----|----|----|
       o
----|----|----|----|----|
   5  10  15  20  25

----|----|----|----|----|
       o
----|----|----|----|----|
   5  10  15  20  25

----|----|----|----|----|
      o
----|----|----|----|----|
   5  10  15  20  25

Knowing that the perceived location of the "o" is being controlled, I can now infer that if the reference value has been the same through all the frames, its value must be somewhere near 9. But I still can't see it directly, as you say you can. Maybe I need special perception training to see it?

When Martin tells us that the inference that the reference value must be somewhere around 9, he tacitly equates the theoretical entity inside the subject with the observed state of the cursor, and the use of the word “referenceâ€? to label both of these things invites him to do so. Similarly, Rick’s argument that control is an observable phenomenon also depends on equating these two things.Â
But although the theoretical entity and the state of the observed variable may be correlated with each other (and strongly correlated if control is good), the two are quite distinct, and it makes no sense to me to call them by the same name.Â
Imagine in Martin’s thought experiment that there is a large nearly constant disturbance, unseen by the observer, which in the absence of any action by the subject would create a substantial deflection of the cursor from left to right. You might think of it as a strong wind constantly blowing from west to east. In this case, the reference value intended by the subject might be something distinctly different from 9, say 5, but because control is never perfect, the cursor ends up hovering right around 9 despite the best efforts of the subject to keep it at 5.Â
I just did a run of a simulated control system with a gain of 10 (slowing factor 0.0012), a reference value of 5, and a step-function disturbance of 40. Once the curve for the observable variable (call it the cursor) had settled down, its value was 9.10. (Since the graph of results from this simulation is really boring, I won’t bother to reproduce it.)
In my scenario, the best inference an observer of Martin’s experiment could make is that the reference value for the subject's control of the perceptual variable is 9, but we know from our “analyst’s perspectiveâ€? that it's really 5. Thus, the observed state of the environmental variable is NOT the intended reference value.Â
I would agree with Martin’s side of this argument. Even if an observed variable is apparently under control, what you can observe is not necessarily the intended reference value.Â
Of course, my perspective on all this comes from thinking and writing about collective control, where the observed state of an environmental variable being acted upon by multiple control systems with different references will end up conforming to a virtual reference value that may be sharply different from what any of the individual actors intended.Â
Best to all,
Kent

[Martin Taylor 2017.06.16.15.20]

[From Rick Marken (2017.06.16.1210)]

MT: ... it may be extremely difficult or even impossible for an external observer to determine whether a control system is acting if the reference value is changing as unpredictably as is the disturbance or more so (PCT language) and the observer can see only the PCT "input".

RM: I don't believe that that's true. In my Mind Reading demo, for example, the computer is able to "read the mind" -- that is, determine the controlled variable -- of a person who is varying the reference for the state of the controlled variable at least as unpredictably as the disturbances to that variable (which are sine waves and, thus, quite predictable).Â

BL: Rick, I suggest that you re-read what Martin actually said. He did not say impossible period. Â

···

On Jun 16, 2017, at 2:43 PM, Martin Taylor <<mailto:mmt-csg@mmtaylor.net>mmt-csg@mmtaylor.net> wrote:

On Thu, Jun 15, 2017 at 11:20 PM, Bill Leach <<mailto:wrleach@cableone.net>wrleach@cableone.net> wrote:
RM: Yes, I know. I guess I just get frustrated by the fact that the only thing that ever gets discussed about the TCV on CSGNet is how it (supposedly) can't be done in this or that situation. If CSGNet is really supposed to be a place where, as Martin says, "advances and lacunae in Perceptual Control Theory can be discussed in ways that conform to normal science" then, since the TCV is the basic methodology of PCT science, it seems to me that discussions of the TCV should be about how it can be done, not how it can't.Â

Aside from the fact that nothing in the prior context was about the TCV and how it can or can't be done, and apart from the phrase "since the TCV is the basic methodology of PCT science", I more or less agree.

The problem, though, is one that I find frequently in your postings and publications. It represents a profoundly different approach to science than mine. Mine is a two-pronged notion that (a) one should see what seem to be the consequences of what one thinks one knows, and preferably see if there are viable alternative ways of developing contrary consequences, and (b) try to demonstrate that what one knows, or one's derivation of the consequences, is wrong. You usually tell us that if one answer fits the facts, then that is the right answer. I think the objective of science is to figure out why the obviously correct answer is wrong, and accept it only provisionally, and then only if there seems no alternative. To find out that my idea was clearly wrong is a glorious feeling (mixed perhaps with transient disappointment), because it brings me nearer to whatever truth science can reveal.

Consider your paper on the relation between target cursor separation and control quality. You argued that my interpretation was wrong, and that the controlled variable was the inclination of the line between target and cursor. I said that my subjective impression was that you were correct, and you asked me if I would co-author a paper. I declined, because I could see no way to distinguish the two possibilities mathematically, since for small angles tan theta is very close to theta. But you published anyway, declaring victory.

In the case of the TCV, it is important, I think, to define its strengths and limitations. Under the right conditions, it can be quite powerful, but when used wrongly, it can mislead. That's what powerful tools do. So it's important to note things like "If the TCV determines that x+y is better controlled than x*y under these conditions, we can discard x*y as the controlled variable, but we canNOT say that x+y is the controlled variable; we can say that it is correlated with the controlled variable." On the other hand, if the question is which avatar of three is being controlled, then the answer is unequivocal.Â

I think discussions of the TCV should be equally how it can be done and about how it can't. The reason I so often point out problems with it is your gung-ho attitude that it solves all problems and shouldn't be questioned. A counterweight is necessary.

Martin

--
Richard S. MarkenÂ
"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
                --Antoine de Saint-Exupery

[Martin Taylor 2017.06.16.23.42]

[From Kent McClelland 2017.06.16.1600]

I’m struck by Rick Marken’s contention " that ‘reference state’ refers to
the value of an observable variable (like the position of the
controlled avatar in the Mind Reading demo) while ‘the value
of the reference signal’ refers to the value of the
theoretical entity that accounts for the reference state of
the observed variable.� (2017.06.15.0925)

      Whatever labels

Bill Powers once used in one of his papers, I find it
confusing to apply the same label—“referenceââ€?—to the state of
an observed environmental variable as to the unobservable
variable in the theoretical  process of control that, according to
advocates of PCT, can account for the state of the observed
variable. Calling them both by the same name leads to
confusion, I think, because it’s easy to equate one with the
other, and they need to be kept sharply distinct.

      It's an interesting point, and I'm not

sure how to deal with it. From one viewpoint they are “sharply
distinct”, but from another they are not. If we assume that PCT is
correct, then the reference state that drives the value of the
perception is the one that comes from inside the organism. But
just as the perceptual value corresponds to the value of an
environmental variable, so the reverence value for the perception
can be projected into the environment as the value of the
environmental variable that would generate a perceptual value
equal to the reference.

  In that sense, the internal and environmental versions of the

reference value are not easily distinguished. They can be
distinguished only by what operations are in principle available
to determine them, or by their place on a diagram of the
theoretical control loop. The internal value could, in principle,
be measured by some neural probe or other whose readout gave the
value. The external value could only be found by manipulating the
environmental variable until it produced a perception equal to
that value. Otherwise, they have to be distinguished by the fact
that an external observer who has no neural probe can observe only
the movements of the external variable and must infer the
reference value from that.

  Now you come up with an experiment that shows there is a third

kind of reference value, which I will call an “Apparent
Reference”. This is the value that the observer would infer from
the movements of the external variable, which I said just above
would be the environmental correlate of a perception that equalled
the internal reference value. But you show that this is not
necessarily the value that the external observer would infer. So
now we have three kinds: the internal value that is in principle
measurable by getting at the physiological machinery, the
environmental projection of that value, and the value that would
be inferred by an observer of the motions of the environmental
variable.

  That's even more confusing if you want to keep them all distinct

in talking about them. I guess one could use a form such as Ref(O)
(the original, internal one), Ref§, the projected one, and
Ref(I) the inferred one, but that would be pretty cumbersome. My
weak proposal is that the context usually allows at least Ref(O)
to be distinguished from the other two and we should perhaps just
us “reference” for it. As for the others, I guess that if the
context seems likely to lead to confusion we could just say
“projected reference” and “apparent reference” or something like
that.

  I hope you don't discover a fourth one any time soon!

  Martin
···

On Thu, Jun 15, 2017 at
11:20 PM, Bill Leach wrleach@cableone.net wrote:

                      BL: Rick, I suggest that you re-read

what Martin actually said. He did not say
impossible period. Â

                    RM: Yes, I know. I guess I just get

frustrated by the fact that the only thing that
ever gets discussed about the TCV on CSGNet is
how it (supposedly) can’t be done in this or
that situation. If CSGNet is really supposed to
be a place
where, as Martin says, “advances and lacunae
in Perceptual Control Theory can be discussed
in ways that conform to normal science” then,
since the TCV is the basic methodology of PCT
science, it seems to me that discussions of
the TCV should be about how it can be done,
not how it can’t.Â

                                    MT:

… it may be extremely
difficult or even impossible for
an external observer to
determine whether a control
system is acting if the
reference value is changing as
unpredictably as is the
disturbance or more so (PCT
language) and the observer can
see only the PCT “input”.

                                  RM: I don't believe

that that’s true. In my Mind
Reading demo, for example, the
computer is able to “read the
mind” – that is, determine the
controlled variable – of a person
who is varying the reference for
the state of the controlled
variable at least as unpredictably
as the disturbances to that
variable (which are sine waves
and, thus, quite predictable).Â

[From Kent McClelland 2017.06.17.1145]

These diagrams look good to me, Rupert, and let me say that I read the relevant chapter from your dissertation and thought it was a really nice discussion of the engineering approach to control systems in comparison to the PCT approach.

ledklgdblnfmohng1.png

ecojkmojkojmlpgg1.png

···

DF: I would be most interested in your evaluation of Rupert’s discussion of the engineering perspective on control, spelled out in Chapter 3, section 3.4
The Conventional Error, in his Ph.D. dissertation (2000).

[From Kent McClelland 2017.06.17.1155]

Yes, Rick, your post stamped (2016.06.16.1620) in reply to Martin clears up some of the discrepancy for me. If you take the “reference state of the observed variable� as the state corresponding to no action on the part of the controller, then
it is clearly an observable phenomenon. Martin’s right, however, that when you label this state of the observed variable as the “reference state�, you’re appealing to a theoretical concept.

I’d add that determining the reference state of an observed variable might be tricky in practice. In a very simple experimental situation like a tracking experiment, it’s clearcut, but in “the field� there might be lots of different reasons that
a person took no action to control a perception: exhaustion, giving up, turning one’s attention to the control of different perception, coercion, lack of the necessary tool at hand to bring to bear enough physical force to the control the perception, blockage
of sensory stream that would allow the person to form a perception to compare to its reference value, etc. Speaking personally (or perhaps politically), I have lots of perceptions that don’t conform to my references for them that I take no action to control.

···

[From Rick Marken (2016.06.16.1730)]

Kent McClelland (2017.06.16.1600)–

KM: I’m struck by Rick Marken’s contention " that ‘reference state’ refers to the value of an observable variable (like the position of the controlled avatar in the Mind Reading demo) while ‘the value of the reference
signal’ refers to the value of the theoretical entity that accounts for the reference state of the observed variable.â€? (2017.06.15.0925)

RM: I hope my post [From Rick Marken (2016.06.16.1620)] in the “Environmental Reference?” thread clears things up for you. If not, feel free to ask (or tell) me about it.

Best

Rick

Whatever labels Bill Powers once used in one of his papers, I find it confusing to apply the same label—“referenceâ€?—to the state of af an observed environmental variable as to the unobservable variable in the theoretical process
of control that, according to advocates of PCT, can account for the state of the observed variable. Calling them both by the same name leads to confusion, I think, because it’s easy to equate one with the other, and they need to be kept sharply distinct.

To make my point, I’d like to direct attention back to the demo Martin described in his post yesterday ( 2017.06.15.13.29), because it seems to me that
Rick didn’t come grips with it in his reply (2017.06.16.1000).

Here’s the demo as Martin described it:

Imagine that the following is one frame from a compensatory tracking study, in which the subject is influencing the lateral position of the “o”
cursor. I have put markers on the guide lines to serve as a ruler (in practice the computer would do the measurement internally).

`----|----|----|----|----|

   o

----|----|----|----|----|

5   10   15   20   25

` Can you see in that environment the current location of the “o” cursor? I suspect that you can, and would say that the “o” is at location 8. What is the location of the reference,
which you say is similarly observable in the environment? You must be able to see it, but I can’t.

Some empty space deliberately left here while you think about whether you perceive the environmental reference location for the “o” in the same way as you perceive the current
location of the “o”.

.

.

.

.

[I’ve snipped out a bunch of identical lines here.]

.

.

Here are a few more positions of the cursor in some well separated sample frames:

`----|----|----|----|----|

    o

----|----|----|----|----|

5   10   15   20   25

`

`----|----|----|----|----|

     o

----|----|----|----|----|

5   10   15   20   25

`

`----|----|----|----|----|

    o

----|----|----|----|----|

5   10   15   20   25`

`----|----|----|----|----|

     o

----|----|----|----|----|

5   10   15   20   25

``----|----|----|----|----|

   o

----|----|----|----|----|

5   10   15   20   25

` Knowing that the perceived location of the “o” is being controlled, I can now infer that if the reference value has been the same through all the frames, its value must be
somewhere near 9. But I still can’t see it directly, as you say you can. Maybe I need special perception training to see it?

When Martin tells us that the inference that the reference value must be somewhere around 9, he tacitly equates the theoretical entity inside the subject with the observed state of the cursor, and the use of the word “reference� to label both of these things
invites him to do so. Similarly, Rick’s argument that control is an observable phenomenon also depends on equating these two things.

But although the theoretical entity and the state of the observed variable may be correlated with each other (and strongly correlated if control is good), the two are quite distinct, and it makes no sense to me to call them by the same name.

Imagine in Martin’s thought experiment that there is a large nearly constant disturbance, unseen by the observer, which in the absence of any action by the subject would create a substantial deflection of the cursor from left to right. You might
think of it as a strong wind constantly blowing from west to east. In this case, the reference value intended by the subject might be something distinctly different from 9, say 5, but because control is never perfect, the cursor ends up hovering right around
9 despite the best efforts of the subject to keep it at 5.

I just did a run of a simulated control system with a gain of 10 (slowing factor 0.0012), a reference value of 5, and a step-function disturbance of 40. Once the curve for the observable variable (call it the cursor) had settled down, its value
was 9.10. (Since the graph of results from this simulation is really boring, I won’t bother to reproduce it.)

In my scenario, the best inference an observer of Martin’s experiment could make is that the reference value for the subject’s control of the perceptual variable is 9, but we know from our “analyst’s perspectiveâ€? that it’s really 5. Thus, the
observed state of the environmental variable is NOT the intended reference value.

I would agree with Martin’s side of this argument. Even if an observed variable is apparently under control, what you can observe is not necessarily the intended reference value.

Of course, my perspective on all this comes from thinking and writing about collective control, where the observed state of an environmental variable being acted upon by multiple control systems with different references will end up conforming
to a virtual reference value that may be sharply different from what any of the individual actors intended.

Best to all,

Kent

On Jun 16, 2017, at 2:43 PM, Martin Taylor mmt-csg@mmtaylor.net wrote:

[Martin Taylor 2017.06.16.15.20]

[From Rick Marken (2017.06.16.1210)]

Aside
from the fact that nothing in the prior context was about the TCV and how it can or can’t be done, and apart from the phrase "* since
the TCV is the basic methodology of PCT science* ",
I more or less agree.

The
problem, though, is one that I find frequently in your postings and publications. It represents a profoundly different approach to science than mine. Mine is a two-pronged notion that (a) one should see what seem to be the consequences of what one thinks one
knows, and preferably see if there are viable alternative ways of developing contrary consequences, and (b) try to demonstrate that what one knows, or one’s derivation of the consequences, is wrong. You usually tell us that if one answer fits the facts, then
that is the right answer. I think the objective of science is to figure out why the obviously correct answer is wrong, and accept it only provisionally, and then only if there seems no alternative. To find out that my idea was clearly wrong is a glorious feeling
(mixed perhaps with transient disappointment), because it brings me nearer to whatever truth science can reveal.

Consider
your paper on the relation between target cursor separation and control quality. You argued that my interpretation was wrong, and that the controlled variable was the inclination of the line between target and cursor. I said that my subjective impression was
that you were correct, and you asked me if I would co-author a paper. I declined, because I could see no way to distinguish the two possibilities mathematically, since for small angles tan theta is very close to theta. But you published anyway, declaring victory.

In
the case of the TCV, it is important, I think, to define its strengths and limitations. Under the right conditions, it can be quite powerful, but when used wrongly, it can mislead. That’s what powerful tools do. So it’s important to note things like “If the
TCV determines that x+y is better controlled than xy under these conditions, we can discard xy as the controlled variable, but we canNOT say that x+y is the controlled variable; we can say that it is correlated with the controlled variable.” On the other
hand, if the question is which avatar of three is being controlled, then the answer is unequivocal.

I
think discussions of the TCV should be equally how it can be done and about how it can’t. The reason I so often point out problems with it is your gung-ho attitude that it solves all problems and shouldn’t be questioned. A counterweight is necessary.

Martin


Richard S. Marken

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
–Antoine de Saint-Exupery

BL: Rick, I suggest that you re-read what Martin actually said. He did not say impossible period.

RM: Yes, I know. I guess I just get frustrated by the fact that the only thing that ever gets discussed about the TCV on CSGNet is how it (supposedly) can’t be done in this or that situation. If CSGNet is really supposed to be a place
where, as Martin says, “advances and lacunae in Perceptual Control Theory can be discussed in ways that conform to normal science” then, since the TCV is the basic methodology of PCT science, it seems to me that discussions of the TCV should be about how it
can be done, not how it can’t.

On Thu, Jun 15, 2017 at 11:20 PM, Bill Leach wrleach@cableone.net wrote:

MT: … it may be extremely difficult or even impossible for an external observer to determine whether a control system is acting if the reference value is changing as unpredictably as is the disturbance or more so (PCT language)
and the observer can see only the PCT “input”.

RM: I don’t believe that that’s true. In my Mind Reading demo, for example, the computer is able to “read the mind” – that is, determine the controlled variable – of a person who is varying the reference for the state of the controlled variable
at least as unpredictably as the disturbances to that variable (which are sine waves and, thus, quite predictable).

[From Rick Marken (2017.06.17.1200)]

ecojkmojkojmlpgg1.png

ledklgdblnfmohng1.png

···

[From Kent McClelland 2017.06.17.1145]

KM: These diagrams look good to me, Rupert,

RM: I agree. Perfect!Â

and let me say that I read the relevant chapter from your dissertation and thought it was a really nice discussion of the engineering approach to control systems in comparison to the PCT approach.

On Jun 17, 2017, at 6:50 AM, Rupert Young rupert@perceptualrobots.com wrote:

[From Rupert Young (2017.06.17 13.00)]

I’ve just been updating versions of these based on Wiener’s original, with additional PCT labels. Do these look correct in terms of labels and separation between organism and the world?

Regards,
Rupert

DF: I would be most interested in your evaluation of Rupert’s discussion of the engineering perspective on control, spelled out in Chapter 3, section 3.4
The Conventional Error, in his Ph.D. dissertation (2000).Â

Richard S. MarkenÂ

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
                --Antoine de Saint-Exupery

[From Rick Marken (2017.06.17.1230)]

···

Kent McClelland (2017.06.17.1155)_-

KM: Yes, Rick, your post stamped (2016.06.16.1620) in reply to Martin clears up some of the discrepancy for me. If you take the “reference state of the observed variableâ€? as the state corresponding to no action on the part of the controller, then
it is clearly an observable phenomenon.

RM: Great!

Â

KM: Martin’s right, however, that when you label this state of the observed variable as the “reference stateâ€?, you’re appealing to a theoretical concept.Â

RM: Right, though I’d say that you are appealing to a theory – rather than a theoretical construct – that says you are dealing with a control system that acts to bring variables to reference states. The reference state is an observation, not a theoretical concept. But you do have to assume that you are dealing with a control system and know control theory in order to know that you can determine a reference state empirically by looking for the state of a controlled variable at which the system no longer produces output aimed at changing the state of that variable.Â

KM: I’d add that determining the reference state of an observed variable might be tricky in practice.

RM: Yes indeed. I have never done research aimed at determining the reference state of a controlled variable. And it’s never been necessary. My research has been aimed at determining what the controlled variable was – what type of perception was being controlled. The reference state of that variable, to the extent that I needed to know it (I didn’t need to know it to create the Mind Reading demo, for example), was specified by the reference signal parameter of the model of the behavior under study (which was the case in the object interception modeling, for example). So this whole discussion of whether or not the reference state of a controlled variable is the state of an environmental variable that can be observed is probably of little practical relevance (in terms of doing research). I think is mainly of philosophical interest. And maybe it is relevant to getting the right mapping of the PCT model to actual behavior.

BestÂ

Rick

In a very simple experimental situation like a tracking experiment, it’s clearcut, but in “the fieldâ€? there might be lots of different reasons that
a person took no action to control a perception: exhaustion, giving up, turning one’s attention to the control of different perception, coercion, lack of the necessary tool at hand to bring to bear enough physical force to the control the perception, blockage
of sensory stream that would allow the person to form a perception to compare to its reference value, etc. Speaking personally (or perhaps politically), I have lots of perceptions that don’t conform to my references for them that I take no action to control.Â

Â

On Jun 16, 2017, at 7:29 PM, Richard Marken rsmarken@gmail.com wrote:


Richard S. MarkenÂ

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
                --Antoine de Saint-Exupery

[From Rick Marken (2016.06.16.1730)]

Kent McClelland (2017.06.16.1600)–

KM: I’m struck by Rick Marken’s contention " that ‘reference state’ refers to the value of an observable variable (like the position of the controlled avatar in the Mind Reading demo) while ‘the value of the reference
signal’ refers to the value of the theoretical entity that accounts for the reference state of the observed variable.â€? (2017.06.15.0925)

RM: I hope my post [From Rick Marken (2016.06.16.1620)] in the “Environmental Reference?” thread clears things up for you. If not, feel free to ask (or tell) me about it.Â

BestÂ

Rick

Â

Whatever labels Bill Powers once used in one of his papers, I find it confusing to apply the same label—â“referenceâ€?—to the state of an observed environmental variable as to the unobservable variable in the theoretical  process
of control that, according to advocates of PCT, can account for the state of the observed variable. Calling them both by the same name leads to confusion, I think, because it’s easy to equate one with the other, and they need to be kept sharply distinct.Â

To make my point, I’d like to direct attention back to the demo Martin described in his post yesterday ( 2017.06.15.13.29), because it seems to me that
Rick didn’t come grips with it in his reply (2017.06.16.1000).Â

Here’s the demo as Martin described it:Â

Imagine that the following is one frame from a compensatory tracking study, in which the subject is influencing the lateral position of the “o”
cursor. I have put markers on the guide lines to serve as a ruler (in practice the computer would do the measurement internally).

`----|----|----|----|----|

      o

----|----|----|----|----|

   5  10  15  20  25

` Can you see in that environment the current location of the “o” cursor? I suspect that you can, and would say that the “o” is at location 8. What is the location of the reference,
which you say is similarly observable in the environment? You must be able to see it, but I can’t.

Some empty space deliberately left here while you think about whether you perceive the environmental reference location for the “o” in the same way as you perceive the current
location of the “o”.

.

.

.

.

[I’ve snipped out a bunch of identical lines here.]

.

.

Here are a few more positions of the cursor in some well separated sample frames:

`----|----|----|----|----|

       o

----|----|----|----|----|

   5  10  15  20  25

`

`----|----|----|----|----|

       o

----|----|----|----|----|

   5  10  15  20  25

`

`----|----|----|----|----|

       o

----|----|----|----|----|

   5  10  15  20  25`

`----|----|----|----|----|

       o

----|----|----|----|----|

   5  10  15  20  25

``----|----|----|----|----|

      o

----|----|----|----|----|

   5  10  15  20  25

` Knowing that the perceived location of the “o” is being controlled, I can now infer that if the reference value has been the same through all the frames, its value must be
somewhere near 9. But I still can’t see it directly, as you say you can. Maybe I need special perception training to see it?

When Martin tells us that the inference that the reference value must be somewhere around 9, he tacitly equates the theoretical entity inside the subject with the observed state of the cursor, and the use of the word “referenceâ€? to label both of these things
invites him to do so. Similarly, Rick’s argument that control is an observable phenomenon also depends on equating these two things.Â

But although the theoretical entity and the state of the observed variable may be correlated with each other (and strongly correlated if control is good), the two are quite distinct, and it makes no sense to me to call them by the same name.Â

Imagine in Martin’s thought experiment that there is a large nearly constant disturbance, unseen by the observer, which in the absence of any action by the subject would create a substantial deflection of the cursor from left to right. You might
think of it as a strong wind constantly blowing from west to east. In this case, the reference value intended by the subject might be something distinctly different from 9, say 5, but because control is never perfect, the cursor ends up hovering right around
9 despite the best efforts of the subject to keep it at 5.Â

I just did a run of a simulated control system with a gain of 10 (slowing factor 0.0012), a reference value of 5, and a step-function disturbance of 40. Once the curve for the observable variable (call it the cursor) had settled down, its value
was 9.10. (Since the graph of results from this simulation is really boring, I won’t bother to reproduce it.)

In my scenario, the best inference an observer of Martin’s experiment could make is that the reference value for the subject’s control of the perceptual variable is 9, but we know from our “analyst’s perspectiveâ€? that it’s really 5. Thus, the
observed state of the environmental variable is NOT the intended reference value.Â

I would agree with Martin’s side of this argument. Even if an observed variable is apparently under control, what you can observe is not necessarily the intended reference value.Â

Of course, my perspective on all this comes from thinking and writing about collective control, where the observed state of an environmental variable being acted upon by multiple control systems with different references will end up conforming
to a virtual reference value that may be sharply different from what any of the individual actors intended.Â

Best to all,

Kent

On Jun 16, 2017, at 2:43 PM, Martin Taylor mmt-csg@mmtaylor.net wrote:

[Martin Taylor 2017.06.16.15.20]

[From Rick Marken (2017.06.16.1210)]

Aside
from the fact that nothing in the prior context was about the TCV and how it can or can’t be done, and apart from the phrase "* since
the TCV is the basic methodology of PCT science* ",
I more or less agree.

The
problem, though, is one that I find frequently in your postings and publications. It represents a profoundly different approach to science than mine. Mine is a two-pronged notion that (a) one should see what seem to be the consequences of what one thinks one
knows, and preferably see if there are viable alternative ways of developing contrary consequences, and (b) try to demonstrate that what one knows, or one’s derivation of the consequences, is wrong. You usually tell us that if one answer fits the facts, then
that is the right answer. I think the objective of science is to figure out why the obviously correct answer is wrong, and accept it only provisionally, and then only if there seems no alternative. To find out that my idea was clearly wrong is a glorious feeling
(mixed perhaps with transient disappointment), because it brings me nearer to whatever truth science can reveal.

Consider
your paper on the relation between target cursor separation and control quality. You argued that my interpretation was wrong, and that the controlled variable was the inclination of the line between target and cursor. I said that my subjective impression was
that you were correct, and you asked me if I would co-author a paper. I declined, because I could see no way to distinguish the two possibilities mathematically, since for small angles tan theta is very close to theta. But you published anyway, declaring victory.

In
the case of the TCV, it is important, I think, to define its strengths and limitations. Under the right conditions, it can be quite powerful, but when used wrongly, it can mislead. That’s what powerful tools do. So it’s important to note things like “If the
TCV determines that x+y is better controlled than xy under these conditions, we can discard xy as the controlled variable, but we canNOT say that x+y is the controlled variable; we can say that it is correlated with the controlled variable.” On the other
hand, if the question is which avatar of three is being controlled, then the answer is unequivocal.Â

I
think discussions of the TCV should be equally how it can be done and about how it can’t. The reason I so often point out problems with it is your gung-ho attitude that it solves all problems and shouldn’t be questioned. A counterweight is necessary.

Martin


Richard S. MarkenÂ

"Perfection is achieved not when you have nothing more to add, but when you
have nothing left to take away.�
                --Antoine de Saint-Exupery

BL: Rick, I suggest that you re-read what Martin actually said. He did not say impossible period. Â

RM: Yes, I know. I guess I just get frustrated by the fact that the only thing that ever gets discussed about the TCV on CSGNet is how it (supposedly) can’t be done in this or that situation. If CSGNet is really supposed to be a place
where, as Martin says, “advances and lacunae in Perceptual Control Theory can be discussed in ways that conform to normal science” then, since the TCV is the basic methodology of PCT science, it seems to me that discussions of the TCV should be about how it
can be done, not how it can’t.Â

On Thu, Jun 15, 2017 at 11:20 PM, Bill Leach wrleach@cableone.net wrote:

MT: … it may be extremely difficult or even impossible for an external observer to determine whether a control system is acting if the reference value is changing as unpredictably as is the disturbance or more so (PCT language)
and the observer can see only the PCT “input”.

RM: I don’t believe that that’s true. In my Mind Reading demo, for example, the computer is able to “read the mind” – that is, determine the controlled variable – of a person who is varying the reference for the state of the controlled variable
at least as unpredictably as the disturbances to that variable (which are sine waves and, thus, quite predictable).Â

Dear Eetu…

···

From: Eetu Pikkarainen [mailto:eetu.pikkarainen@oulu.fi]
Sent: Tuesday, June 13, 2017 9:58 AM
To: csgnet@lists.illinois.edu
Subject: VS: Controling observables (was Re:… long live William T. Powers)

[Eetu Pikkarainen 2017-06-13]

(This is comment to the end of Martin’s message.)

Yes I know that �stabilization� is problematic term and I hope that some English speaker would invent a proper alternative.

HB : I once already analyzed why “stabilization� is proper term when LCS control is in question.

  1.   One of the best sociologists (although for me is the best) Kent McClelland is using this term. I really respect him as a scientist and I beleive he knows why he is using this term. If you didn't read anything from him I warmly suggest you his writings.
    
  2.   I beleive I have physiological evidences to support term stability.
    
  3.   Term stability is by my oppinion showing some loose »simetry« in »efects of organism on environment« and »effects of environment on organism« although control is asymetry between organism and environment.
    
  4.   Ashby used terms »stability« and »ultrastability« to denote organisms functioning in respect to »influences« from environment.
    

Beside other reasons I see the strongest support to term stabiliity in physiological terminology, which describe functioning of nervous system. That’s what PCT is most about. How organisms, specialy nervous system function. The term stability is not only used in describing how nervous system »controls stability«, but it is also close to central physiological term »homeostasis«. It means keeping almost constant, stable conditions in controlling system. We can add »constant conditions« inside genetically determined references.

Term »stabilizing« is also used for patients to recover from injures or other ill state.

So it sems that with control we get some stable, constant environment which differ radically from outer environment. Inside control system there is control which is maintaining »contant conditions« and outside in ordinary environment there are forces described by physics and chemistry how function. So if we look on cell as »controlled island« inside ordinary environment it looks like stable structure which is maintained by itself (control, autopoiesis). It’s not the »same structure« all the time although it could look like to somebody. So how could we call something that is maintaining almost constant structure and organization in world full of physical and chemistry disturbances (perturbances) which are destabilizing structure all the time. Anyway anything what is happening with stability of organisms have nothing to do with »protection« of organisms stability. With this term Rick is showing the extent of his misunderstanding of PCT and control in Living Control System (LCS).

Boris

The general meaning of “stabilization� (to become stabile) is one (important) special case of the concept for which we need a term. The core meaning of this concept is something like “the process where a subject affects something in the environment in a such way that this something is changed and/or kept in a such state that the subject gets a perception which is near to his/her reference value�. If this process is looked at from subject’s viewpoint it is “behavior� or “action� but now it should be looked from the viewpoint of the object (that something). So it is “to be acted on�. I have two suggestions: “constrained� and “adjusted�. (If I remember right Martin once suggested “constrain�?)

Why not “control�? Because in PCT the subjects action is based on (and explained by) the control of perception, where the perceptual signal is compared to reference signal and if there is difference then that difference is tried to minimize by affecting the object of the perception. So “control� already has a strict and pivotal meaning and use. It is confusing to call one special constituent of that “control� also control. Of course you could say like Rick that we control by controlling, but then we use the same term for two essentially different processes – essentially different for understanding PCT as a theory. At least they should be clearly marked different for example by some subscript like:

control(env) and control(per). Control(env) or “environmental control� is the concept used in everyday and (probably) engineering language where the whole process is projected to the environment. In PCT that control(env) is the part of control(per) (control of perception), the part which takes place in the environment of the controlling subject and is perceivable to observer and causes consequences for other subjects.

But anyway for me it sounds more clear to use clearly different terms: When we act we control our perceptions by constraining the environmental objects of our perceptions by our behavior (and by a feedback path).

More technically and generally: “A controlling system (or unit) controls its perceptions by constraining its environment.�

Eetu

Lähettäjä: Martin Taylor [mailto:mmt-csg@mmtaylor.net]
Lähetetty: 12. kesäkuutata 2017 21:03
Vastaanottaja: csgnet@lists.illinois.edu
Aihe: Controling observables (was Re:… long live William T. Powers)

[Martin Taylor 2017.05.12.13.14]

[Eetu Pikkarainen 2017-06-12]

EP: The issue is ONLY that we do NOT control anything in the environment but only our own perceptions - even though the control is realized by affecting the environment.

RM: This is simply not true. See my recent post to Martin. I’ll just repeat my last point: If people controlled only their perceptions then there would be no way for anyone other than the person doing the controlling to know this.

The truth of that depends entirely on your definition of control. If the definition of control requires that there be an observer, the underlying philosophy is one that says definitively: “If a tree falls in the forest and no organism is around to hear it, it DOES NOT make any sound.”, then what you say could possibly be true. Not otherwise. I do not subscribe to that philosophy, and that fact may contribute to a lot of our disagreements. I would say that it doesn’t matter whether anyone else can know whether you are controlling something – even you may not know it, as according to PCT, most control is unconscious.

As I think of the way the world works, control happens (or does not happen) whether or not there is an external Experimenter/Analyst/Observer available in the neighbourhood to assess the environmental dynamics associated with it. From what Eetu quoted, I understand you to be saying that “control” is nothing more than a perception in the brain of an observer who has developed a perceptual function, the output of which can be labelled “degree of control”. From your quote above and from your other writing, you think control does not exist in the world outside the Observer.

EP: I think you partly replied on behalf of in your message [From Rick Marken (2017.06.11.1640)] but only partly. You wrote:

“a controlled perception is an inference based on observation of the fact that certain variables in what is perceived by an observer as the subject’s environment are controlled (maintained in reference states, protected from disturbance).â€?

I agree with this quote. Whether the observer perceives control as occurring is different from the Analyst inferring how that control is executed (itself another perception). This is true in both philosophies. What either of them perceives is affected by what is happening in their real environments, which is where the control they both do (or do not) perceive is (or is not) occurring.

This means that an observer sees something special happen in the environment and from that s/he infers that the subject is controlling some perception. As part of that inference the observer can do tests and try to disturb the subject’s controlling. What the observer is seeing is not control, but stabilization, see below…

/p>

EP: Question is about the definition of control in PCT.

RM: The definition of control in PCT is completely in terms of observable variables.

In engineering it is, but in PCT? Not if one is actually serious about PCT as a theory. In PCT (as in much of science) the observables are only part of the way an Observer sees the world. A PCT observer sees the observables, but sees them only in terms of controlled perceptions, not as the be-all and end-all of what is happening.

It is an “objective” definition in the sense that others besides the observer can confirm the observation. The definition of control in PCT is: maintenance of a variable in a reference state, protected from disturbance. “Perception” is not part of this definition; perception is a component of the theory that accounts for this objectively observable phenomenon.

Yes, that’s why a non-PCT observer might use a definition couched in terms of observables only. A PCT observer would take the observables as a starting point confirmable by another observer, not the end point. As several of us have mentioned, not only recently but over the years, no reference state can be observed in the environment. Reference states must be inferred from the ways the observables change. So “maintenance of a variable in a reference state” implies comparing apples to apples, not apples to oranges or an observable state to a reference state that is necessarily inferred. However, an inferred state that we call a “Perception” can legitimately be compared with an inferred reference state, and therefore can be controlled. An observable environmental state cannot.

EP: Perception may not be a part of the definition, but the reference is. Like perception, also the reference is only inside the subject / organism. It is not principally unobservable, but at the current and near future state of neurology it is not possible to measure the reference value of the subject. So the definition of control (in PCT) cannot be defined completely in terms of observable variables.

Exactly so.

EP: When you see (the fact) that something is (in a certain way and conditions) stabilized in the environment of the subject, you can infer from that to (the fact of) control. It is like all science a hypothetical and fallible inference, but by experience a more reliable inference than many everyday alternatives. That is just the glory of science: you can know something what you have not (immediately) perceived.

I have to quibble about the word “stabilize” and its relatives, because most of our controlled variables are far from stable. When I type this message, the reference values for my perceptions of the locations of my fingertips move all over the keyboard, quite quickly. When I walk, reference values for various muscle tensions are always changing. And so it goes, all the way up the hierarchy, the changes getting slower the higher in the hierarchy one goes (all Perceptual Control Theory, of course).

These rapid (theoretical) variations in reference value make it harder to “observe” control happening. Consider one of Rick’s “mind-reading” demos, in which a number of objects move randomly around the screen (three, but any number could). The subject is asked to make one of them go where she chooses. If she chooses to make the track look as random as the tracks of the others, there’s no way another person looking at the screen could tell which one was being controlled. But the computer can, because it knows precisely where the controlled one would go if only it made that decision, moment by moment. Nothing in such a demo would be “stabilized” except the relationship between the subject’s reference location as it changes and her perception of the location as that changes. And that is not observable by anyone else.

Martin