# Another question- sound

**URL:** <http://discourse.iapct.org/t/another-question-sound/1143>\
**Category:** CSG2011\
**Created:** [November 24, 2011, 4:52am UTC](http://discourse.iapct.org/t/another-question-sound/1143 "2011-11-24T04:52:31Z")\
**Posts on this page:** 8\
**Page:** 1

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**Post date:** [November 24, 2011, 4:52am UTC](http://discourse.iapct.org/t/another-question-sound/1143/1 "2011-11-24T04:52:31Z")

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( Gavin  
Ritz 2011.11.24.17.38NZT)

I’m listening to music and I’m  
singing in my head, no vocal sound. Lying on the bed very still in a room, no  
movement.

Is the sound a disturbance or a controlled  
variable?

What is the output variable? (is it the singing  
in my head)

Regards

Gavin

> **···**
>

---

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**Author:** ![Bill\_Powers1](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/8e7dd6/32.png) [@Bill\_Powers1](http://discourse.iapct.org/u/Bill_Powers1)\
**Post date:** [November 24, 2011, 3:35pm UTC](http://discourse.iapct.org/t/another-question-sound/1143/2 "2011-11-24T15:35:29Z")

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[From Bill Powers (2011.11.24.0634 MDT)]

> (Gavin Ritz  
> 2011.11.24.17.38NZT)
> 
> I’m listening to music and I’m singing in my head, no vocal sound. Lying  
> on the bed very still in a room, no movement.
> 
> Is the sound a disturbance or a controlled  
> variable?

The sound is a controlled variable. A control system does not perceive  
disturbances (as causes) – they are known to the control system only as  
unintended changes in controlled variables. Of course another system  
inside you may perceive the cause of the disturbance, but that’s a  
different control system. It doesn’t have to exist for the first control  
system to work. And “you,” the conscious observer, may be aware  
of both the controlled variable and the cause of the disturbance, and  
many other perceptions going on at the same time. But “you” are  
only a spectator.

> What is the output variable? (is it the singing in my  
> head)

The output is a reference signal which normally enters the comparator of  
at least one lower-order control system, telling it what amount of its  
perceptual variable it is to produce. In the imagination mode, however,  
that output is switched to enter the input function of the higher control  
system instead of the lower comparator, and that signal takes the place  
of the perceptual signal that would normally be generated by the lower  
system. So you get the impression of hearing singing even though no  
singing is coming into your ears. This follows from the postulate that  
perceptions exist only as afferent signals generated by perceptual input  
functions.

Most of this is discussed in B:CP.

As to the “function” problem,  
those definitions you were citing are from some very abstract branches of  
mathematics, not the sort of math that a mere physicist/engineer like me  
uses. Unless you have mastered those higher realms of mathematics, I  
recommend sticking to the simple practical ideas that are used in  
engineering. If you have mastered them, then you will have a  
communication problem here until you learn to translate from the abstract  
to the particular kinds of math at my level of understanding.

At my level, part of the problem may simply be language. We engineers  
often say that a variable symbolized as x has a numerical value, say 2.5,  
in some units of measure. But we don’t say it that way: we just say  
“x is 2.5.” Of course x is NOT 2.5, it’s an alphabetic symbol  
standing for a number which might be any real (i.e., on an infinitely  
fine scale) number that just happens to be, at the present moment,  
2.500… .

So when we say a function is a variable, what we mean is that by  
evaluating the mathematical expression defining the function, we can  
compute a magnitude

that we call the value of the function, and represent that value by a  
symbol for another variable. Because the arguments of the function are  
variables, the value computed from them is also variable, so the value of  
the function is a variable, too. Another variable can be defined and set  
equal to the value of the function, and our shorthand for that is to say  
that the variable is a function of the arguments. This does not mean that  
a function f(v) “is” a variable, any more than we would mean  
that x “is” 2.5. We mean that the value of the function is  
variable and can be symbolized as such.

p = f(v) is read out loud as “p is the function f of the variable  
v”. Of course this does not mean that the FORM of the function is  
symbolized as p. It means that the VALUE of the function, obtained by  
some set of operations on the value of v, is symbolized as the value of  
p.

Again in engineering terms, mathematical functions are used as  
descriptions of the operation of various components of a system. A  
capacitor, for example, can be treated as a function that converts the  
flow of a certain number of electrons into a voltage. Using E for  
“electromotive force” which just means voltage, Q for quantity  
of charge, and C for capacitance (itself a function of the area and  
separation of the plates of the capacitor), we have in general

E = f(Q,C) or specifically

E = Q/C

The first form simply says that the voltage E depends on Q and C in some  
unspecified way indicated by the symbol f. The second form spells out  
exactly how E depends on those other variables, so we don’t need  
the functional notation. Of course we can assign the symbol f to the  
expression Q/C and use other letters for other forms of functions. Then  
when we refer to f(Q,C) we mean only the expression Q/C and not any other  
form.

The functional notation is used when we want to state a dependency  
without giving the details of its form (perhaps because we don’t know it  
yet). There are all sorts of theorems in advanced algebra that deal with  
functions without ever saying what their forms are. But in engineering we  
want to know what the forms are, eventually. In PCT we speak of input  
functions and output functions, without knowing what forms they may take  
in a specific application. Different functions will involve different  
mathematical expressions, so we give them different names.

So you can see that you’re right in thinking of a function as a  
transformation or mapping of the arguments into the value of the  
function. But the shorthand engineer-talk doesn’t disagree with that. It  
just leaves out some details.

Best,

Bill P.

---

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**Author:** ![CARTER\_CLOYD](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/c/958977/32.png) [@CARTER\_CLOYD](http://discourse.iapct.org/u/CARTER_CLOYD)\
**Post date:** [November 24, 2011, 5:42pm UTC](http://discourse.iapct.org/t/another-question-sound/1143/3 "2011-11-24T17:42:07Z")

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Happy thanksgiving everyone

> **···**
>
> Sent from my Verizon Wireless BlackBerry
> 
> * * *
> 
> **From:** Bill Powers [powers\_w@FRONTIER.NET](mailto:powers_w@FRONTIER.NET)
> 
> **Sender:** “Control Systems Group Network (CSGnet)” [CSGNET@LISTSERV.ILLINOIS.EDU](mailto:CSGNET@LISTSERV.ILLINOIS.EDU)
> 
> **Date:** Thu, 24 Nov 2011 08:35:29 -0700
> 
> **To:** [CSGNET@LISTSERV.ILLINOIS.EDU](mailto:CSGNET@LISTSERV.ILLINOIS.EDU)
> 
> **ReplyTo:** “Control Systems Group Network (CSGnet)”  
> [CSGNET@LISTSERV.ILLINOIS.EDU](mailto:CSGNET@LISTSERV.ILLINOIS.EDU)
> 
> **Subject:** Re: Another question- sound
> 
> [From Bill Powers (2011.11.24.0634 MDT)]
> 
> > (Gavin Ritz  
> > 2011.11.24.17.38NZT)
> > 
> > I’m listening to music and I’m singing in my head, no vocal sound. Lying  
> > on the bed very still in a room, no movement.
> > 
> > Is the sound a disturbance or a controlled  
> > variable?
> 
> The sound is a controlled variable. A control system does not perceive  
> disturbances (as causes) – they are known to the control system only as  
> unintended changes in controlled variables. Of course another system  
> inside you may perceive the cause of the disturbance, but that’s a  
> different control system. It doesn’t have to exist for the first control  
> system to work. And “you,” the conscious observer, may be aware  
> of both the controlled variable and the cause of the disturbance, and  
> many other perceptions going on at the same time. But “you” are  
> only a spectator.
> 
> > What is the output variable? (is it the singing in my  
> > head)
> 
> The output is a reference signal which normally enters the comparator of  
> at least one lower-order control system, telling it what amount of its  
> perceptual variable it is to produce. In the imagination mode, however,  
> that output is switched to enter the input function of the higher control  
> system instead of the lower comparator, and that signal takes the place  
> of the perceptual signal that would normally be generated by the lower  
> system. So you get the impression of hearing singing even though no  
> singing is coming into your ears. This follows from the postulate that  
> perceptions exist only as afferent signals generated by perceptual input  
> functions.
> 
> Most of this is discussed in B:CP.
> 
> As to the “function” problem,  
> those definitions you were citing are from some very abstract branches of  
> mathematics, not the sort of math that a mere physicist/engineer like me  
> uses. Unless you have mastered those higher realms of mathematics, I  
> recommend sticking to the simple practical ideas that are used in  
> engineering. If you have mastered them, then you will have a  
> communication problem here until you learn to translate from the abstract  
> to the particular kinds of math at my level of understanding.
> 
> At my level, part of the problem may simply be language. We engineers  
> often say that a variable symbolized as x has a numerical value, say 2.5,  
> in some units of measure. But we don’t say it that way: we just say  
> “x is 2.5.” Of course x is NOT 2.5, it’s an alphabetic symbol  
> standing for a number which might be any real (i.e., on an infinitely  
> fine scale) number that just happens to be, at the present moment,  
> 2.500… .
> 
> So when we say a function is a variable, what we mean is that by  
> evaluating the mathematical expression defining the function, we can  
> compute a magnitude
> 
> that we call the value of the function, and represent that value by a  
> symbol for another variable. Because the arguments of the function are  
> variables, the value computed from them is also variable, so the value of  
> the function is a variable, too. Another variable can be defined and set  
> equal to the value of the function, and our shorthand for that is to say  
> that the variable is a function of the arguments. This does not mean that  
> a function f(v) “is” a variable, any more than we would mean  
> that x “is” 2.5. We mean that the value of the function is  
> variable and can be symbolized as such.
> 
> p = f(v) is read out loud as “p is the function f of the variable  
> v”. Of course this does not mean that the FORM of the function is  
> symbolized as p. It means that the VALUE of the function, obtained by  
> some set of operations on the value of v, is symbolized as the value of  
> p.
> 
> Again in engineering terms, mathematical functions are used as  
> descriptions of the operation of various components of a system. A  
> capacitor, for example, can be treated as a function that converts the  
> flow of a certain number of electrons into a voltage. Using E for  
> “electromotive force” which just means voltage, Q for quantity  
> of charge, and C for capacitance (itself a function of the area and  
> separation of the plates of the capacitor), we have in general
> 
> E = f(Q,C) or specifically
> 
> E = Q/C
> 
> The first form simply says that the voltage E depends on Q and C in some  
> unspecified way indicated by the symbol f. The second form spells out  
> exactly how E depends on those other variables, so we don’t need  
> the functional notation. Of course we can assign the symbol f to the  
> expression Q/C and use other letters for other forms of functions. Then  
> when we refer to f(Q,C) we mean only the expression Q/C and not any other  
> form.
> 
> The functional notation is used when we want to state a dependency  
> without giving the details of its form (perhaps because we don’t know it  
> yet). There are all sorts of theorems in advanced algebra that deal with  
> functions without ever saying what their forms are. But in engineering we  
> want to know what the forms are, eventually. In PCT we speak of input  
> functions and output functions, without knowing what forms they may take  
> in a specific application. Different functions will involve different  
> mathematical expressions, so we give them different names.
> 
> So you can see that you’re right in thinking of a function as a  
> transformation or mapping of the arguments into the value of the  
> function. But the shorthand engineer-talk doesn’t disagree with that. It  
> just leaves out some details.
> 
> Best,
> 
> Bill P.

---

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**Author:** ![rsmarken](http://discourse.iapct.org/user_avatar/discourse.iapct.org/rsmarken/32/3553_2.png) [@rsmarken](http://discourse.iapct.org/u/rsmarken)\
**Post date:** [November 24, 2011, 6:02pm UTC](http://discourse.iapct.org/t/another-question-sound/1143/4 "2011-11-24T18:02:18Z")

</div>

[From Rick Marken (2011.11.24.1000)]

> Bill Powers (2011.11.24.0634 MDT)]
> 
> > GR: I’m listening to music and I’m singing in my head, no vocal sound. Lying  
> > on the bed very still in a room, no movement.
> > 
> > Is the sound a disturbance or a controlled  
> > variable?

> BP: The sound is a controlled variable. A control system does not perceive  
> disturbances (as causes) – they are known to the control system only as  
> unintended changes in controlled variables.

RM: I would just add that it’s not just the sound (as acoustic signal) but perceptual aspects of the sound that are the controlled variables, such as the specific music, the type of music and/or whether it is music rather than talk or silence. Let’s say the main controlled variable is music. Then disturbances are anything that can affect the state of that variable. If the sound is coming from a radio then disturbances include weather conditions which can blow down the broadcast antenna and change what you hear from music to silence. Or an emergency broadcast message might interrupt the music. Or the station can suddenly change formats from music to talk. In those cases yo might act to deal with the disturbance by switching stations or whatever. Of course, these things are rather rare so if the station continues to broadcast music there is no need to do anything to protect that variable from disturbance because the the disturbances are basically constant at zero, for the time being, anyway.

I think it’s important to understand that we are always controlling even when we are doing what seems to be nothing at the moment (because there is no need to do anything). In the situation where one is lying  
on the bed very still in a room, making virtually no movement while listening to music, it appears that there is no controlling going on; but in fact, there is, as would be revealed instantly by the corrective actions that would occur when the music changed to something else, like noise.

Best

Rick

> **···**
>
> –  
> Richard S. Marken PhD  
> [rsmarken@gmail.com](mailto:rsmarken@gmail.com)  
> [www.mindreadings.com](http://www.mindreadings.com)

---

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**Author:** ![BUSINESS\_GAVIN\_HERMA](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/2acd7d/32.png) [@BUSINESS\_GAVIN\_HERMA](http://discourse.iapct.org/u/BUSINESS_GAVIN_HERMA)\
**Post date:** [November 24, 2011, 9:49pm UTC](http://discourse.iapct.org/t/another-question-sound/1143/5 "2011-11-24T21:49:54Z")

</div>

(gavin Ritz  
2011.11.25.10.37NZT)

[From Bill Powers  
(2011.11.24.0634 MDT)]

(Gavin Ritz 2011.11.24.17.38NZT)

At my level, part of the problem may simply be language.

That is the  
point that I’m laboring, language and mathematics have precise  
correlations. This goes back to our dialogue on language, there is no mystery  
in language it’s precise in its relation to mathematics. Verbs are  
nothing else than functions and nouns are nothing else than variables. To labour  
just one minor point about language.

If as  
you say language is a controlled variable then this has massive implications  
for understanding living matter to living matter relationships.

So you can see that you’re right in thinking of a function as a transformation  
or mapping of the arguments into the value of the function. But the shorthand  
engineer-talk doesn’t disagree with that. It just leaves out some details.

I’m  
not right it’s mathematics (have nothing to do with the development of math),  
it’s precise in descriptions. No details can be left out in theoretical descriptions.

Regards

Gavin

---

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**Author:** ![BUSINESS\_GAVIN\_HERMA](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/2acd7d/32.png) [@BUSINESS\_GAVIN\_HERMA](http://discourse.iapct.org/u/BUSINESS_GAVIN_HERMA)\
**Post date:** [November 24, 2011, 10:12pm UTC](http://discourse.iapct.org/t/another-question-sound/1143/6 "2011-11-24T22:12:25Z")

</div>

(gavin Ritz  
2011.11.25.10.58NZT)

[From Bill Powers  
(2011.11.24.0634 MDT)]

(Gavin  
Ritz 2011.11.24.17.38NZT)

What is the output variable? (is it the singing in my head)

The output is a reference signal which normally enters the comparator of at  
least one lower-order control system, telling it what amount of its perceptual  
variable it is to produce. In the imagination mode, however, that output is  
switched to enter the input function of the higher control system instead of  
the lower comparator, and that signal takes the place of the perceptual signal  
that would normally be generated by the lower system. So you get the impression  
of hearing singing even though no singing is coming into your ears. This  
follows from the postulate that perceptions exist only as afferent signals  
generated by perceptual input functions.

I really  
don’t understand these statements clearly, can you please do a drawing  
with the relevant control systems. Drawing 15.33 from B:CP I have Runkel’s  
drawing on page 223 of people Living Things (Fig 19.2), is this it.

Do you know  
what the biological equivalent is for this drawing?

Regards

Gavin

---

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**Author:** ![Bill\_Powers1](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/8e7dd6/32.png) [@Bill\_Powers1](http://discourse.iapct.org/u/Bill_Powers1)\
**Post date:** [November 26, 2011, 4:19pm UTC](http://discourse.iapct.org/t/another-question-sound/1143/7 "2011-11-26T16:19:29Z")

</div>

[From Bill Powers (2011.11.26.0903 MST)]

gavin Ritz  
2011.11.25.10.58NZT –

> [From Bill Powers  
> (2011.11.24.0634 MDT)]
> 
> (Gavin Ritz  
> 2011.11.24.17.38NZT)
> 
> What is the output variable? (is it the singing in my head)
> 
> The output is a reference signal which normally enters the comparator of  
> at least one lower-order control system, telling it what amount of its  
> perceptual variable it is to produce. In the imagination mode, however,  
> that output is switched to enter the input function of the higher control  
> system instead of the lower comparator, and that signal takes the place  
> of the perceptual signal that would normally be generated by the lower  
> system. So you get the impression of hearing singing even though no  
> singing is coming into your ears. This follows from the postulate that  
> perceptions exist only as afferent signals generated by perceptual input  
> functions.
> 
> I really  
> don’t understand these statements clearly, can you please do a drawing  
> with the relevant control systems. Drawing 15.33 from B:CP I have  
> Runkel’s drawing on page 223 of people Living Things (Fig 19.2), is this  
> it.

It’s 15-3 in B:CP, and yes, that’s the figure I would draw now. The  
“memory” box is an attempt to account for how we perceive  
memories of past perceptions, and also how we can reproduce an experience  
that has happened in the past. The imagination connection is shown in the  
diagram, with the switches set so the reference signal (whether derived  
from memory or not) goes back into the perceptual channel instead of the  
comparator. That’s what I call the imagination mode.

> Do you know what the  
> biological equivalent is for this drawing?

No. Neurological evidence for specific neural circuits is almost  
nonexistent – neuroscience just hasn’t progressed that far. More  
generally, of course, there isn’t any mystery about how neurons  
_could_ accomplish the functions shown in the diagram. But nobody  
has actually observed the proposed organization in that Figure. You have  
to take all my figures that refer to neural circuitry as proposals,  
showing one way the proposed functions could be carried out – but not  
the only way. It’s important to know there is at least one way, so the  
proposal isn’t just a wild guess relying on magic, or impossible on the  
face of it. I’ve studied neurology enough to know pretty well some of the  
things neurons can do, and appropximately how they do it. But that’s  
about the level where the literature of neuroscience runs out of  
data.

Best,

Bill P.

---

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**Post date:** [November 26, 2011, 10:14pm UTC](http://discourse.iapct.org/t/another-question-sound/1143/8 "2011-11-26T22:14:51Z")

</div>

(gavin ritz 2011.11.27.11.13NZT)  
[From Bill Powers (2011.11.26.0903 MST)]

gavin Ritz  
2011.11.25.10.58NZT –

> [From Bill Powers  
> (2011.11.24.0634 MDT)]
> 
> (Gavin Ritz  
> 2011.11.24.17.38NZT)
> 
> What is the output variable? (is it the singing in my head)
> 
> The output is a reference signal which normally enters the comparator of  
> at least one lower-order control system, telling it what amount of its  
> perceptual variable it is to produce. In the imagination mode, however,  
> that output is switched to enter the input function of the higher control  
> system instead of the lower comparator, and that signal takes the place  
> of the perceptual signal that would normally be generated by the lower  
> system. So you get the impression of hearing singing even though no  
> singing is coming into your ears. This follows from the postulate that  
> perceptions exist only as afferent signals generated by perceptual input  
> functions.
> 
> I really  
> don’t understand these statements clearly, can you please do a drawing  
> with the relevant control systems. Drawing 15.33 from B:CP I have  
> Runkel’s drawing on page 223 of people Living Things (Fig 19.2), is this  
> it.

It’s 15-3 in B:CP, and yes, that’s the figure I would draw now. The  
“memory” box is an attempt to account for how we perceive  
memories of past perceptions, and also how we can reproduce an experience  
that has happened in the past. The imagination connection is shown in the  
diagram, with the switches set so the reference signal (whether derived  
from memory or not) goes back into the perceptual channel instead of the  
comparator. That’s what I call the imagination mode.

> Do you know what the  
> biological equivalent is for this drawing?

No. Neurological evidence for specific neural circuits is almost  
nonexistent – neuroscience just hasn’t progressed that far. More  
generally, of course, there isn’t any mystery about how neurons  
_could_ accomplish the functions shown in the diagram. But nobody  
has actually observed the proposed organization in that Figure. You have  
to take all my figures that refer to neural circuitry as proposals,  
showing one way the proposed functions could be carried out – but not  
the only way. It’s important to know there is at least one way, so the  
proposal isn’t just a wild guess relying on magic, or impossible on the  
face of it. I’ve studied neurology enough to know pretty well some of the  
things neurons can do, and appropximately how they do it. But that’s  
about the level where the literature of neuroscience runs out of  
data.

GR: Thank you.

GR