A chemical equation of equilibrium and negative feedback

Bj_rn_Simonsen · April 27, 2006, 10:43am

[From Bjorn Simonsen (2006.04.27, 12:55 EUST)]

Martin, I have decided to wait some time with your world model.

Re-Studying Reorganization I met Bill’s sentence in B:CP 2ED page 187, first passage; “Several mechanisms are known to
have such effects; synaptic thresholds can be altered chemically or by neural
signals; …….”.

In this relation I found some texts about our body’s interior
state and I am working with different chemical equations describing our
interior state.

Is it possible to think upon a chemical equation of
equilibrium as a feedback system?

If we have the equation of
equilibrium AB + CD ß> AD + BC (+ energy), there is a concentration of
AB and a concentration of CD. Some of these molecules hit and form AD and BC
until there come equilibrium into being.

It happens that the concentration of AB, BC,
AD or CD sinks and it happens that AB, BC, AD or CD are supplied. When one or
both of the chemicals on one side of the equation of equilibrium sign is
supplied, they form the chemicals on the other side. When the concentration of
one or both of them sinks, they are formed from the chemicals on the other
side.

Is it possible to think upon an equation of
equilibrium as a negative feedback system where e.g. the concentration of CD
expressed in the equilibrium constant is the intrinsic reference signal.

(concentrationAD * concentrationBC/concentrationAB*concentrationCD)
= Equilibrium constant, given a certain temperature.

The real
concentration of CD is the intrinsic signal and the difference between those
values is the error. The output signal is expressed in the same equation we use
in PCT. The gain is an expression dependent on different concentrations.

The
reason for thinking this way is Bill’s sentence above; “……synaptic thresholds can be altered chemically ….”.

Maybe the chemical way we describe our interior state
and the transmitters in the synapses, which also are chemical substances could
be the meting place in the reorganizing system.

Am I far away?

bjorn

···

Richard_Marken2 · April 27, 2006, 4:30pm

[From Rick Marken (2006.04.27.0930)]

Bjorn Simonsen (2006.04.27, 12:55 EUST) --

Re-Studying Reorganization I met Bill�s sentence in B:CP 2ED page187, first passage; �Several mechanisms are known to have such effects; synaptic thresholds can be altered chemically or by neural signals; ��.�.

�Is it possible to think upon a chemical equation of equilibrium as a feedback system?

Definitely not. This is like thinking of a pendulum or a mass on a spring (a mass-spring system) as a feedback systems (as the "complex systems" types do). While the equilibrium state of these systems does look like a reference state for a controlled variable, it's easy to show that it is not by simply applying a disturbance to the apparently controlled variable (the position of the pendulum, the height of the mass on a spring or the relative concentrations in the chemicals in the substrate). The disturbance will be fully effective as long as it is applied (for example, the pendulum bob will be displaced from the resting state for as long as a displacing force is applied to the bob) and the apparent controlled variable returns to the "reference state" only when the disturbance is removed. So these systems fail to pass the test for the controlled variable. So if they are feedback system, their gain is close to zero.

My paper in _Mind Readings_ called "Degrees of freedom in behavior" deals with precisely this issue: the belief that equilibrium systems (sometimes called "coordinative structures" in the psychology literature) can serve as models of purposeful behavior (control).

Best

Rick

···

---

Richard S. Marken Consulting
marken@mindreadings.com
Home 310 474-0313
Cell 310 729-1400

Bill_Powers1 · April 27, 2006, 5:08pm

[From Bill Powers (2006.04.27.1146 MDT)]

Rick Marken (2006.04.27.0930)]

Bjorn Simonsen (2006.04.27, 12:55 EUST) --

Is it possible to think upon a chemical equation of equilibrium as a feedback system?

Definitely not. This is like thinking of a pendulum or a mass on a spring (a mass-spring system) as a feedback systems (as the "complex systems" types do).

There is one kind of chemical system that can be a control system. The main requirement is there there be significant gain around a closed loop of reactions powered by an external energy source. This can happen in biochemical systems where enzymes can provide large amounts of amplification (there may be inorganic system involving catalysts where this also happens). The energy comes from the substrate chemicals at the input to the reactions. The controlled variable is a chemical concentration affected by the output products.

See "Dynamic Analysis of Enzyme Systems" by K. Hayashi and N. Sakamoto. Japan Scientific Societies Press and Springer-Verlag, 1986. See page 267, "3.Feedback Control System", for an example. I used this example in my paper on the Origins of Purpose (World Futures).

Pedro Mendes set up this system for me in his biochemical simulator, "Gepasi.", and verified that if the reference signal is varied, the feedback (perceptual) signal tracks it. The allosteric enzyme in this system acts as a combined comparator and output function, with a gain of roughly 50,000. The reference input signal tends to increase the population of enzymes in the active form; the feedback input signal tends to decrease that population. That's how the comparison takes place.

The time constants are long enough to make the system stable, as you can tell from the Figures on p. 268-269. The authors were more interested in the approach to the final state after a very large perturbation of the system, but if you look at the right-hand side of each figure you'll see that a steady state is reached. Once the system is in this state it will continue to track changes in the reference signal that vary at normal speeds, keeping the error small.

Best,

Bill P.

P.S. I found that in removing Mary's subscription to CSGnet, I also removed my own, accidentally. Probably a good idea at the time.

PPS: Gepasi is available on the Web, and was free the last time I looked. If you know any biochemistry you can used it to simulate biochemical systems. I don't know enough about biochemistry to use it.

Bj_rn_Simonsen · April 27, 2006, 7:27pm

[From Bjorn Simonsen (2006.04.27,21:35 EUST)]

From Rick Marken (2006.04.27.0930)

Is it possible to think upon a chemical
equation of equilibrium as a

feedback system?

Definitely not. This is like thinking of a
pendulum or a mass on a

spring (a mass-spring system) as a feedback
systems (as the "complex

systems" types do). While the equilibrium
state of these systems does

look like a reference state for a controlled
variable, it’s easy to

show that it is not by simply applying a
disturbance to the apparently

controlled variable (the position of the pendulum,
the height of the

mass on a spring or the relative concentrations in
the chemicals in the

substrate). The disturbance will be fully
effective as long as it is

applied (for example, the pendulum bob will be
displaced from the

resting state for as long as a displacing force is
applied to the bob)

and the apparent controlled variable returns to
the “reference state”

only when the disturbance is removed. So these
systems fail to pass the

test for the controlled variable. So if they are
feedback system, their

gain is close to zero.

My paper in Mind Readings called “Degrees
of freedom in behavior”

deals with precisely this issue: the belief that
equilibrium systems

(sometimes called “coordinative
structures” in the psychology

literature) can serve as models of purposeful
behavior (control).

I agree that the pendulum idea and
the mass spring idea can’t serve as models of purposeful behavior, but it looks
to me that the pendulum system is influenced by negative feedback after the
pendulum bob is released. I think upon the tension in the pendulum suspension
as the “perceptual signal” and a tension in the pendulum suspension like the
gravity force as the reference (this happens when the pendulum hang still.

But I see differences between a
pendulum system and a chemical equation of equilibrium. I am not qualified to
understand my interior biochemical state. But the varying state of my organism owing
to oxygen can be described in the chemical equation

**C₆H₁₂O₆ + 6O₂ß> 6CO₂

6H₂O**

(I know this can be written quite different at
the cell level, but maybe those equations are sub models working the same way).

The concentration of carbon dioxide in the
blood when you sit on a chair and have a body temperature like 37 degrees
centigrade may be the reference value. When you start running you use more
oxygen and the interior signal (the real concentration of carbon dioxide) becomes
greater. You shall not think upon the learned hierarchy and the respiratory
centre in the medulla oblongata, just think upon the equation.

When the carbon dioxide concentration increases,
more carbon dioxide and water becomes carbohydrate and oxygen than oxygen and
carbohydrate becomes carbon dioxide and water. (Maybe I remember the “mass effect
law” wrong today).

If you don’t tell me more convincing that I
am wrong, I will continue my studying. I have never heard about hierarchical
chemical equations, but I think the equation above is a steering equation for other
chemical equations in the blood. And those chemical equations are steering for
still other chemical equations.

Maybe your next mail stops my study?

I will look in your “Mind Readings”.

bjorn

···

Bj_rn_Simonsen · April 27, 2006, 8:09pm

[From Bjorn Simonsen (2006.04.27,22:20 EUST)]

From Bill Powers (2006.04.27.1146 MDT)

There is one kind of chemical system that can be a
control system.

The main requirement is there be significant gain
around a

closed loop of reactions powered by an external
energy source. This

can happen in biochemical systems where enzymes
can provide large

amounts of amplification (there may be inorganic
system involving

catalysts where this also happens). The energy
comes from the

substrate chemicals at the input to the reactions.
The controlled

variable is a chemical concentration affected by
the output products.

I am not well enough qualified reading chemistry. But
I understand what you say about enzymes and catalysts. I was thinking upon gain
as a time derived function of the concentration of a substance.

See “Dynamic Analysis of Enzyme Systems”
by K. Hayashi and N.

Sakamoto. Japan Scientific Societies Press and
Springer-Verlag, 1986.

See page 267, “3.Feedback Control
System”, for an example. I used

this example in my paper on the Origins of Purpose
(World Futures).

I have noted your advisement, but I don’t find the
book at the library. I have just started
on “Biochemistry
/ Donald Voet, Judith G. Voet. - 3rd ed”.

Thank
you for your comment, maybe you will hear from me later when I better know what
I write.

P.S. I found that in removing Mary’s subscription
to CSGnet, I also

removed my own, accidentally. Probably a good idea
at the time.

You shall know I feel much better when I see you on
the list. I know you know to take care of yourself. And I wish you good luck.

bjorn

DagArchive · April 27, 2006, 12:36pm

[From Dag Forssell (2006.04.27.13:35 PST)]

Don’t forget

The Neglected Phenomenon of Negative Feedback Control at [http://www.livingcontrolsystems.com/intro_papers/neglected_phenomenon.pdf

](http://www.livingcontrolsystems.com/intro_papers/neglected_phenomenon.pdf)and the “reprint” of

The origins of purpose: the first metasystem transitions

···

at http://www.livingcontrolsystems.com/intro_papers/evolution_purpose.pdf Best, Dag At 10:08 AM 4/27/2006, you wrote:

[From Bill Powers (2006.04.27.1146 MDT)]

Rick Marken (2006.04.27.0930)]

Bjorn Simonsen (2006.04.27, 12:55 EUST) –

Is it possible to think upon a chemical equation of equilibrium as a feedback system?

Bj_rn_Simonsen · April 28, 2006, 9:55am

[From Bjorn
Simonsen (2006.04.28,11:55 EUST)]

Martin Taylor
2006.04.27.17.03

I agree that the pendulum idea and the mass
spring

idea can’t serve as models of purposeful behavior,

but it looks to me that the pendulum system is

influenced by negative feedback after the pendulum

bob is released

The difference between the restoration of the
pendulum

(or a spring, and the like) is that for them the energy

required for the restoration is provided by whatever

moved the item away from its equilibrium position.

It’s just a conversion of the form of the energy to

jn the case of the pendulum) gravitational potential

energy provided by whatever pushed the pendulum,

and, on restoration, the dissipation of that energy into heat.

May I go into some hair-splitting comments?

Many systems have their distinctive stamp. Isn’t it
possible to think upon a pendulum as a simple, a very simple negative feedback
system. In our learned hierarchy, which mostly is a negative feedback system,
the reference signal most of the time represent potential energy. The same is
to say about the perceptual signal. It is only when our awareness focuses on
the reference or the perception, we know that the potential energy is converted
to effective energy. And alterations in the environment that don’t influence
our sensory cells are not disturbances.

In a pendulum system the reference is zero potential
energy, the “perceptual signal” is the real tension in the pendulum rod and the
disturbances are every thing that pushes the pendulum, wind and light (?)(photons).

I am not a physicist, but I think that the potential
energy in a pendulum system is dissipated to heat as long as there is kinetic
energy in the system. Heat is the effect of clashing air molecules when the pendulum
moves. If the pendulum hangs in vacuum, heat is the effect of torsion in the
point of suspension (?).

You are a control system. When you stand on a ships
deck in heavy weather, you have a reference for standing upright. Your output
counteracts the disturbance.

A pendulum is a control system. When the wind blows it
out of vertical position, the difference between the negative value of gravity
and the tension in the pendulum rod influenced by a gain (the way it hangs)
counteracts the disturbance.

I said earlier that a pendulum can’t serve as a model
of purposive behavior. Now I will say it depends on what purposive behavior is.

When a child is born it has a reference controlling
the grasping reflex. I think it is congenital. The organization of some nerves is congenital.

A pendulum has a reference controlling for hanging
vertical. The organization of operating
forces is a result of the pendulum system.

A child has a variety of purposes. The pendulum is a
very simple system with only one purpose. Some purposes are congenital. Some
purposes are learned. Learning (reorganizing) is a way of organizing.

In a control system, whether it be physical or
chemical

or whatever, the energy required for restoration comes

from a source independent of the energy suplied by the

disturbnace.

Is it energy that controls a thermostat to experience a temperature of 20 degrees centigrade. Do a
thermostat controlling for 25 degrees possess more energy than a thermostat
controlling for 20 degrees? Is it the energy or the organization that result in
negative feedback? If you cut through the feedback channel in a negative
feedback system, you change the organization. And you loose the purpose
concept.

I just ask.

The control system’s “perception”
extracts

negligible energy from the disturbed system, but the

output can supply as much energy as is available from

its supply (conceivably up to the energy released by an H-bomb!).

Is an exploding H-bomb an effect of the output signal
in a negative feedback system?

Equilibrium systems do tend toward restoration of

their central values, but they do so without outside

energy sources (other than that supplied by
whatever

disturbed them away from the equilibrium in the first place).

Yes, but they also do so with outside energy sources.
If hydrogen iodide is supplied with thermal energy, you get iodine and hydrogen
when the temperature is more than 180 degrees centigrade.

2.5 kcal + 2HJ ß> H₂+ J₂(exhalation)

I think the mass effect constant (dependent
on temperature) tells us the reference for the concentration of iodide. If we
take the heat away, the equilibrium is moved to the left.

bjorn

Martin

Bill_Powers1 · April 28, 2006, 12:50pm

[From Bill Powers (2006.06.28.0645 MDT)]

Martin has it right. While a pendulum is a negative feedback system (applying a force to the pendulum results in an equal and opposite force at the point of application), it does not control to any appreciable degree. If it were a good control system, the same force applied to the pendulum would not move it significantly. The active part of the control system would draw on external energy sources to create an equal and opposite force before the pendulum had moved more than a fraction of a millimeter. The restoring force would not come from the potential energy put into the pendulum by the disturbance acting through a distance. It would come from a power supply plugged into the wall socket and a motor driven by an error signal and a power amplifier. This would prevent the disturbance from putting any significant amount of energy into the pendulum, because while the force would be the same, the distance through which it acts would be far smaller.

Overgeneralizing results in the loss of Bateson's "differences that make a difference."

Best,

Bill P.

Martin_Taylor2 · April 28, 2006, 2:37pm

[Martin Taylor 2006.04.28.10.05]

[From Bjorn Simonsen (2006.04.28,11:55 EUST)]
Martin Taylor 2006.04.27.17.03
>>I agree that the pendulum idea and the mass spring

idea can't serve as models of purposeful behavior,
but it looks to me that the pendulum system is
influenced by negative feedback after the pendulum
bob is released

>The difference between the restoration of the pendulum

(or a spring, and the like) is that for them the energy
required for the restoration is provided by whatever
moved the item away from its equilibrium position.
It's just a conversion of the form of the energy to
jn the case of the pendulum) gravitational potential
energy provided by whatever pushed the pendulum,
and, on restoration, the dissipation of that energy into heat.

May I go into some hair-splitting comments?
Many systems have their distinctive stamp. Isn't it possible to think upon a pendulum as a simple, a very simple negative feedback system.

Write the equations, and that will tell. If you have an equation in which thre is something of the form x(t) = f(x(t-delta), y, z, ....), then you have shown it is a feedback system. Whether the feedback is positive or negative depends on the actual equation.

In our learned hierarchy, which mostly is a negative feedback system, the reference signal most of the time represent potential energy.

Where did THAT come from?

The reference signal always represents a desired state of a perceptual signal. The perceptual signal may represent, say, whether my wife's face looks happy, or whether the hole I'm digging is 1 metre deep. I can't reconcile either of those, or most of my other (consciously available) reference signals with a desire to see something have a particular value of potential energy.

The same is to say about the perceptual signal.

Actually, my comment above applies primarily to the perceptual signal, because that is what is affected by the state of the outer world. The reference signal doesn't "represent" anything other than the desired value of the perceptual signal, so if it "represents" something in the outer world, that something is whatever the perceptual signal represents.

In a pendulum system the reference is zero potential energy,

If there's a control system involved (which is more than just a negative feedback system, there must be some variable that is set. The equation must be of the form x(t) = f(x(t-delta1), r(t-delta2), y, z, ...), where r(t) is the reference signal, and the form of the equation is such that

x(t) - r(t-delta2) < x(t-delta1) - r(t-delta2)

Now, I grant you that r(t) might be a constant, in which case you might be tempted to elide it from the representation. But it's always there. A simple negative feedback system doesn't have that r(t) term.

You are a control system. When you stand on a ships deck in heavy weather, you have a reference for standing upright. Your output counteracts the disturbance.

But if I were like a pendulum, I would stay tilted as long as the deck stayed tilted. So there's a difference between me and the pendulum. I make myself more upright when the deck tilts -- or try to.

>In a control system, whether it be physical or chemical

or whatever, the energy required for restoration comes
from a source independent of the energy suplied by the
disturbnace.

Is it energy that controls a thermostat to experience a temperature of 20 degrees centigrade. Do a thermostat controlling for 25 degrees possess more energy than a thermostat controlling for 20 degrees?

As I pointed out previously, the perceptual sensor takes as little energy from the perceived system as it possibly can. It's the furnace, not the thermostat, that provides the energy to maintain the temperature at 20, and the furnace does use more energy to maintain the temperature at 25 (assuming it's winter).

Is it the energy or the organization that result in negative feedback? If you cut through the feedback channel in a negative feedback system, you change the organization. And you loose the purpose concept.

Perfectly true. A control system is a special form of negative feedback system, in which there exists a reference value, and in which the output gain exceeds the input gain and the energy for counteracting a disturbance is obtained from a separate source.

I just ask.
>The control system's "perception" extracts

negligible energy from the disturbed system, but the
output can supply as much energy as is available from
its supply (conceivably up to the energy released by an H-bomb!).

Is an exploding H-bomb an effect of the output signal in a negative feedback system?

Depends how it is used. If it is used as the output in a control system, as was the case before the Test ban treaty came into force, then yes.

>Equilibrium systems do tend toward restoration of

their central values, but they do so without outside

>energy sources (other than that supplied by whatever

disturbed them away from the equilibrium in the first place).

Yes, but they also do so with outside energy sources. If hydrogen iodide is supplied with thermal energy, you get iodine and hydrogen when the temperature is more than 180 degrees centigrade.

2.5 kcal + 2HJ �> H2 + J2 (exhalation)

I think the mass effect constant (dependent on temperature) tells us the reference for the concentration of iodide. If we take the heat away, the equilibrium is moved to the left.

And if you put a magnet near a pendulum with an irom bob, its equilibrium is moved away from vertical. In neither case do I see a separate energy source being used to couteract the effect of an outside disturbance that is supplying energy to change the state of a system.

However, if a control system used the magnet to counter the effect of the wind on the pendulum, that would be using the separate energy source (magnet) to counter the energy of the disturbance (wind). If the magnet is moved (or its power level altered) by the output process of the control system, it's an energy source separate from the disturbance. If it is placed by an ouside agency, it's part of the disturbance.

In your HJ example, if the 2.5 kcal is supplied from a source varied according to whether a control system wants to see H + J or HJ, that's one thing. If the HJ sample is blown near a heat source by the wind, the heat energy is just part of the disturbance.

Equilibrium and control aren't the same, even if sometimes the simple dynamics are indistinguishable.

Martin

Bj_rn_Simonsen · April 29, 2006, 6:37am

[From Bjorn Simonsen (2006.04.29,08:45 EUST)]

From Bill Powers (2006.06.28.0645 MDT)

Martin has it right. While a pendulum is a
negative

feedback system (applying a force to the pendulum

results in an equal and opposite force at the point

of application), it does not control to any

appreciable degree.

I think your second sentence above is another way to
say what I said in my comment to Rick.

From Bjorn Simonsen (2006.04.27,21:35 EUST)

I agree that the pendulum idea and the mass

spring idea can’t serve as models of purposeful

behavior, but it looks to me that the pendulum

system is influenced by negative feedback after

the pendulum bob is released.

There is the chance that I read you wrong.

If it were a good control system, the same force

applied to the pendulum would not move it

significantly. The active part of the control

system would draw on external energy sources to

create an equal and opposite force before the

pendulum had moved more than a fraction

of a millimeter.

I absolutely agree that if the pendulum is a control system it is not a good control system. There are many not
good control systems. Is a thermostat a good control system? If you open the
window in your living room a very cold winter day, it takes about the same time
to create an equal and opposite force before the room temperature comes back to
the set point temperature.

The pendulum is a very simple and bad control system. Its
single purpose (if it is correct to use the word “purpose”) is on the lowest
level, the intensity level.

The restoring force would not

come from the potential energy put into the

pendulum by the disturbance acting through

a distance. It would come from a power

supply plugged into the wall socket and a motor

driven by an error signal and a power amplifier.

Yes, if it should be a good control system.

Overgeneralizing results in the loss of Bateson’s
"differences that

make a difference."

Overgeneralization directs us often in a wrong direction.

I don’t know Bateson well enough. I associate his name with family therapy
where the family is “a
biosocial, feedback governed, error activated system”.

bjorn

Richard_Marken2 · April 29, 2006, 3:42pm

[From Rick Marken (2006.04.29.0840)]

Bjorn Simonsen (2006.04.29,08:45 EUST)

I absolutely agree that _if_ the pendulum is a control system it is not a _good_ control system. There are many not good control systems. Is a thermostat a good control system? If you open the window in your living room a very cold winter day, it takes about the same time to create an equal and opposite force before the room temperature comes back to the set point temperature.

I think this misses the fact that pendulum barely controls at all while the thermostat, though not perfect, controls quite well. If control is measured in terms of stability of the controlled variable (stability measured as the ratio of observed to expected variation in the controlled variable; S = v(O)/v(E)) then the stability of the pendulum is probably something like S = 0.0000000001 whereas the stability of the thermostat is probably something like S = 1000. So the thermostat is about 10 E12 times better than the pendulum as a controller.

So you can say that both the pendulum and thermostat are poor controllers but that the pendulum is worse. But this strikes me as similar to saying that both George W. Bush and Bill Clinton are poor presidents but that Bush is worse. It just doesn't capture the fact that Bush, like the pendulum, has near zero competence whereas Clinton, who, like the thermostat, is not perfect, is something like 10 E 12 better than Bush, which is not an insignificant difference (except to the 32% of the US population who would vote for Hitler or Stalin if Fox news told them that was the right thing to do).

Best regards

Rick

···

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Richard S. Marken Consulting
marken@mindreadings.com
Home 310 474-0313
Cell 310 729-1400

Bj_rn_Simonsen · May 3, 2006, 11:51am

[From Bjorn Simonsen (2006.05.03,14:00 EUST)]

Martin Taylor 2006.04.28.10.05

I have been too busy and I am sorry for answering so
late.

Write the equations, and that will tell. If you

have an equation in which thre is something of

the form x(t) = f(x(t-delta), y, z, …), then

you have shown it is a feedback system. Whether

the feedback is positive or negative depends on

the actual equation.

A pendulum is a dynamical system. It is defined by its
state and by its dynamics or the equation of motion. For an undriven pendulum the
state is uniquely defined by its angle, j and the angular velocity w := d j/d t . The equation
of motion is

d² j /d t² +w²sin j = 0 where w² =g/l ( look at the figure below).

The angular acceleration d² j /d t²=

g/l sin j

I have tried to simulate the moving of the pendulum
bob if I lift it 30 degrees and drop it. I know there is a formula telling how
much the pendulum is damped by meeting air molecules, but I would restrict my
presentation and say that the damping effect is 0.5 percent of the restoring
force F_R = - mg sin j.

I have a pendulum where the pendulum rod is 1 meter. G
= 9.81. And the pendulum bob is 100 gram.

I have set the reference like – m*g and I think the
gravity constant and the effect of hitting air molecules are the disturbances I
know. I think that organization of the pendulum expresses the actual angular
acceleration dependent on the actual angle j. And I think that the damping effect influence
against the restoring force when the pendulum moves towards vertical pendulum position
and it influences with the restoring force when the pendulum moves away prom
vertical pendulum position. In this way I find a net restoring force and the
net angular acceleration.

I think I have a reference and a “perception” and an
error. But I get problems with the output function. This output function cant
change the restoring force. It can’t do anything more than tell the system to
continue as long as the error is greater than zero.

Therefore I accept what you say. The pendulum is not a
negative feedback control system.

In our learned hierarchy, which mostly is a

negative feedback system, the reference signal

most of the time represent potential energy.

Where did THAT come from?

The reference signal always represents a desired

state of a perceptual signal. The perceptual

signal may represent, say, whether my wife’s face

looks happy, or whether the hole I’m digging is 1

metre deep. I can’t reconcile either of those, or

most of my other (consciously available)

reference signals with a desire to see something

have a particular value of potential energy.

Well I may be wrong.

Let us say that you wish to experience your wife’s happy
looking face. Before you open the door to see her, you get a stronger wish to
wash your car. No conflict. When you washed the car for an hour or two, you never
thought about your wife. Your awareness was other “places”. Back to the house
your awareness again was directed toward your wife and you wished to experience
her happy looking face.

If you had controlled for seeing your wife’s happy
looking face before you washed the car, a certain system would have been
working. Some output signals would have established reference signals at lower
levels and you would have behaved in a certain way.

When you washed your car those output signals didn’t
find their way to lower levels (I think).

When you came back to the house, something happened
and the output signals found their way to lower levels. They came from the same
places where they would have come from if you didn’t go and wash the car. They
would have had the same value (maybe you wished to see your wife’s happy face
stronger after washing the car???).

How is it possible to form such output signals, they
must come from somewhere.

Now let me explain what I mean about potential energy.

Nerve cells get signals from their dendrites. The
barrage of dendrite signals contributes to the likelihood of generating an
action potential of its own. If the net signal from the dendrites is large
enough, it causes the sodium channels to open and a new action potential is
generated. This action potentials has a value about 90 millivolts, it can’t be
bigger. But the neuron will generate more and more action potentials and we say
a frequency is formed.

These frequencies are dependent on the length of the
axon, how any sodium channels there are in the axon and how grate is the
concentration of charged sodium ions outside the axon. Every system has its
environment and its qualities. And these environments and qualities define the
potential for the function of neurones.

Maybe I use the word potential wrong?

Equilibrium and control aren’t the same, even if

sometimes the simple dynamics are

indistinguishable.

Control means producing repeatable consequences by
variable actions.

When hydrogen iodide evaporates, more hydrogen and
iodide form more hydrogen iodide.

I thought that was a consequence after evaporation
(action).

I know that we can control for different references.
(We wish something at different degrees). But chemical equilibrium is different
dependent on the temperature.

I will look more at chemical equilibrium equations.

bjorn

oledata10.mso (3.63 KB)

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