[From Rick Marken (2014.03.01.1230)]

## ···

RM: I’m going to move this discussion to a new subject heading that, I think, gets at what this debate is really about, which is: How do we go about trying to understand the behavior of living organisms? Our debate up to this point must seem rather arcane and nit picky to anyone listening in – if anyone is listening in. So in the interests of showing its relevance to the “real world” of understanding living control systems (which is what I think people interested in PCT are interested in) I suggest that we try to frame this in terms of what our differences mean in terms of how we would go about trying to understand the behavior of living systems. So before I answer your post (below) in detail I’ll just say what I think are the “real world” implications of our debate.

What this all means to me is this: Understanding the behavior of living systems is a matter of learning what perceptual variables they control and how they control them. The fact that you can’t understand the true input-output characteristics of a component of a closed-loop system by measuring the input-output characteristics of that component while it is part of a control loop – the subject of the arcane debate between Martin and I – means that the way behavioral scientists have been going about trying to understand the behavior of living systems is misguided.

This is a profoundly important and revolutionary implication of PCT and it is one with which Martin, I believe, disagrees. And this disagreement is based on his belief that you can measure the true input-output characteristics of a component of a closed-loop system by measuring the input-output characteristics of that component while it is part of a control loop. In other words, you can continue trying to understand the behavior of living systems using the methods for understanding their behavior that have been used for the last 100 years.

So that’s the big picture, as I see it. If anyone is listening I’d be interested in their point of view on this topic as well.

Best regards

Rick

[Martin Taylor 2014.03.01.14.05]

Wrong.

`You did it wrong. The reconnection should go to X, not S. X`

represents the output, Z the disturbance, Y the perceptual value.

`Yes.`

`No.`

You did, and did again, perhaps more seriously.

OK, here’s a picture of a control loop, with signal values labelled.

`Now tell me what are the i, the d and the o for the perceptual input`

function component of the loop? I can see it for the comparator

component, (i is p, d is r, and o is e), but what are they for the

output function component? What are they for the Environmental

Feedback component up (the function E( ) in the diagram) to the

point where the disturbance gets added in?`You insist that if you could measure the signals labelled "i" and`

“p” in the diagram, you could not say anything about the function P(

), because it is in a loop, but if you disconnected, say the “o”

connection to the input of E( ), then by looking at “i” and “p” you

could determine P( ). I say that P( ) does not change if you

disconnect “o” from the input of E( ). All that would change would

be the statistics of the values you would see at “i”, not the

relationship between the “i” values and the “p” values. The same

goes for “e” and “o” being determined by, and determining G( ), and

for “o” and “v” being determined by, and determining E( ).`According to you, these relationships are different if the component`

is part of a loop or if the loop is broken at some point. Why so?

(And a mathematical argument would be preferable to an argument

based on “OCT says so” or “I believe strongly that it is so”). If

you are correct, how is it possible to set up and use the control

equations that depend on the relationships between those inputs and

outputs being the same in open-loop and closed-loop situations.`RM: So if by "input-output characteristic" you mean the`

measured (rather than the actual) input-output characteristic of

a system component, then there is no disagreement between us:

components of differently structured circuits, in terms of

whether these circuits are open or closed loop, will not have

the samemeasuredinput-output characteristics even if

they have the sameactualinput-output characteristic.

If that’s what you believe as well then we are on the same page,

indeed.

`MT: It's rather annoying`

to be continually misrepresented in this way.

`RM: Well I sure hope that's true. Is what I say above a more`

accurate representation of your point of view?

No.

`Martin`

Richard S. Marken PhD

www.mindreadings.com

The only thing that will redeem mankind is cooperation.

```
-- Bertrand Russell
```

–

[From Rick Marken (2014.03.01.1045)]

`Martin Taylor`

(2014.02.28.23.15)–

MT: Let’s ask another question. Here are two circuits:

`` Z` ` |`` `` X------|---S---->function>------Y`

X------S—>function>-------Y `

`Now, given a lot of observations of X and Y, is it`

possible to discover the nature of the function in each

circuit? In theory one cannot…`You can, however, measure the function in both diagrams`

if, instead of measuring at X you measure at S.

```
RM: So you say. In an open loop situation, as in your
```

two diagrams above, S is a function of X+Z for the left

diagram and of X on the right. So you would measure the

same relationship between X+Z and Y (on the left) and X

and Y (on the right) as between S and Y in both cases,

taking into account, of course, the relationship between

X+Y and S and X and S respectively. In a closed loop,

however, S is also a function of Y, so measuring the

relationship between S and Y will not reveal the nature of

the function relating S and Y.

`MT: Map these`

subgraph diagrams onto the control loop by taking X to

be the output and Y the perceptual signal.

```
RM: That still leaves them as open-loop diagrams. To
```

map these properly onto a control loop (with X as output

and Y as input, you would have to draw a feedback path

from X back to Y. But then what’s S? The proper way to map

you diagrams onto a control loop is as follows (I’ll just

do it for the right hand diagram):

` Z`

```
` |``
`` X------|---S---->function>------Y`
```

` ^ |`

` | |`

…

`MT: I say that if`

you have a circuit element whose behaviour you can

assess by recording the covariation of its input and

output (not covariance), the assessment is exactly the

same whether the element forms part of a closed loop or

is measured in isolation or in any other network of

connections.

```
RM: Oops, this is quite different than what I showed in
```

my demonstration

```
RM: I went though the trouble to make this point,
```

not because I think it will convince you, Martin; it

looks like you’re pretty committed to the idea that

you can measure the open-loop input -output

characteristics of a system when that system is in a

closed loop.

(and what PCT shows).

```
So it looks like I didn't misrepresent your position
```

at all.

```
RM: Actually, it does. I think you might be saying that
```

you can measure the true i-o of a component of a loop by

looking at the relationship between i and o rather than

between d and o for that component.

```
MT: There is both truth
```

and error in this. See above. The error is not

by Powers, who was talking about the behavioural

illusion and the fact that if you look at the

disturbance and the output, what you learn is

the nature of the environmental feedback path,

not the properties of the organism. And that has

nothing to do with the topic under discussion.