VS: William T. Powers is dead - long live William T. Powers

[Eetu Pikkarainen 2017-06-09 2]

···

EP: Bruce, again I agree largely, but I think you understood me wrong. I was not talking about knowledge (I intended to resume to it sometimes later…) but only about the concept of control. WWhat you write here about the
reality of our environment and the possibility of the reliability of our knowledge about it and especially the truthfulness of scientific knowledge is quite OK. But that was not the issue.

EP: The issue was just the concept of control. And it comes up also below: “[Science]
gives us perceptions plus the best available justification for assuming that
when we control those perceptions we are controlling realities in the environment. [italics by EP]�

EP: From the next possible facts:

  • a person perceives something in the environment

  • there really is something in the environment “causingâ€? just that perception (not a hallucination or error)

  • the person has a reference value for that perception

  • there is a difference between perceptual and reference values causing error and output

  • the output manages to cause certain kind of changes to that something in the environment

  • as a consequence of those changes the person’s perception changes to the refence value

it does NOT follow that the person controls that something in the environment. It follows only that she controls her perception (of that something). As an everyday experience this seems and sounds like the person were
controlling that something in the environment. But just the beauty of the PCT is that we can make the differentiation and understand that all we can ever control is our perceptions.

EP: In everyday life we cannot help saying that someone controls the temperature of the room or that someone did a controlled somersault. But here is theoretical / scientific PCT discussions this either unjustified assumption
or unjustified incoherence causes endless confusion.

EP: We don’t control our environment by controlling our perceptions because strictly speaking there are two different kind of processes which do not both justify the use of the term “control�. Neither do we control our
perceptions by controlling our environment. What we do is that we control our perceptions by affecting some aspect of our environment and as a consequence of that the aspect of environment (usually) becomes stabilized somehow (in a certain way).

Eetu

Please, regard all my statements as questions,

no matter how they are formulated.

Bruce Nevin (2017.06.08.07:48 ET)–

We routinely forget that this is a presumption, and we are justified in doing so.

Eetu Pikkarainen 2017-06-08–

No, we are not justified in doing so if we are scientifically studying “behavior as control of perception�.

I believe that you are convinced that this settles the matter.

The most direct evidence of the reality of that which is perceived is that the environment pushes back and sometimes even bites. To perceive as we wish to perceive requires control; that control often requires effort (against what?);
that control is often disturbed by unforeseen and even unperceived disturbances (whence?); that control often has unintended consequences (arising from what?). John Kirkland’s post in this thread alludes to unintended consequences of that complex of controlled
variables called “industrialization since 1800”.

It would be most peculiar to say that to be scientific we must deny that our experiments, models, and theory give us knowledge of reality. An essential point about PCT is that if the performance of a model conforms very closely to that of a living subject
then the structure of the model informs us about what must necessarily be structures in the living subject.

Look at the fundamental first methodological steps of PCT, the Test for the Controlled Variable. When the experimenter E succeeds in determining what perception (perceptual variable) the subject S is controlling, E is justified in saying that S really has that
perception and is controlling it. This is because E is controlling what E perceives to be the same variable in such a way as to disturb S’s control of it.

To do this, E imagines a transform or translation of a perception that E is controlling. To identify what perception to control, E guesses what S is controlling. The transformation is from E’s point of view to S’s point of view. Point of view upon what? Upon
that which E presumes to be a real variable in the environment which E and S are perceiving from their respective points of view. It is not obvious how one might make sense of the Test, much less carry it out, without this presumption of reality.

Another way to put the conundrum, coming at it from the other direction, is the truism that science never proves anything. Proof is possible only for mathematics and logic.

What science yields us is a succession of provisional and serviceable models of reality (that is, of that aspect of reality of which the particular field of science treats). In other words, it gives us perceptions plus the best available justification for assuming
that when we control those perceptions we are controlling realities in the environment.

When I say provisional and serviceable, I mean that we make do with the best theory that is still standing when the dust of argument settles, or (as in the case of Newtonian vs. relativistic vs. quantum physics) the best theory for the purposes at hand–or
to pick another familiar example, sometimes waves are a more useful model of light, sometimes particles are.

In short, the conclusions of science are high-level perceptions that enable us to control lower-level perceptions better and more reliably than non-science and nonsense conclusions do. And they do so precisely because they (apparently) correspond better to
whatever it is that is really real, independent of our perceptions. They better equip us to identify and control variables that matter to us, to resist disturbances to our control, and maybe even to avoid unintended side effects, or at least recognize them
in time to bring them, too, under control.

Conversely, our perception that we are better able to control under system concepts and principles of science than we are with non-science or nonsense system concepts and principles is our justification for taking the system concepts and principles of science
to be true–that is, taking them to be realities. The argument is circular, but it appears to have been a virtuous circle so far.

/Bruce

On Thu, Jun 8, 2017 at 8:58 AM, Eetu Pikkarainen eetu.pikkarainen@oulu.fi wrote:

[Eetu Pikkarainen 2017-06-08]

Bruce, I largely agree. Some comments though:

[Bruce Nevin (2017.06.08.07:48 ET)]

Begin with some PCT truisms.

All that we can know of our environment is our perceptions of it.

(Not sure about this, but I will turn to it sometimes later – iit depends on definitions. I agree that all our knowledge is based on perceptions.)

All that we can control of our environment is our perceptions of it.

That is funny and fuzzy saying, at least for me: sounds like our perceptions were in the environment. I would say that we cannot control anything in the environment but
only our perceptions of it.

I control many perceptions of our environment without exerting the actions that maintain them under control. Other people, or other agents, exert the actions that maintain them under control.

Or they just happen to be (temporarily) so that our perceptions of them remain near the reference.

Among the evidence that I control such perceptions is the observation that, should control of them lapse, I act in such a way that other people or agents resist the disturbance and re-establish control of them.

A recent example: the street signs for Pinehurst Avenue and Chase Road were swapped, so that each designated the other road. My wife called my attention to it. We contacted the Public Works Department. They fixed it.

What’s the point of this? All that we can know of our environment is our perceptions of it, and we presume that our perceptions are the realities that we perceive. (We presume this even though we know that our perceptions are selective and
omit infinitely many aspects of the environment, some of which we know about because we or others have extended the senses with scientific instruments.) This presumption is justified by our success controlling in the environment and by the like success of
all our human and pre-human ancestors without whose survival we would not be here.

That is extremely important. Our success in control of our perceptions is highly depending on other people and other actors – and finally on the objects or our perceptions.

By this justified presumption, we project the universe of our perceptions into the otherwise unknowable universe of our environment.

That justified presumption extends to the fact that all that we can control of our environment is our perceptions of it. We are justified in the presumption that the controlled variable is in the environment. Every time two or more of us
control what we perceive to be the same variable in the environment we obtain further justification of that presumption. Examples of two or more of us controlling what we perceive to be the same variable in the environment are conflict, collective control,
and the Test for the Controlled Variable.

Here I disagree. This is a natural presumption of our everyday life. But I think that PCT just makes us abandon that presumption at least in theoretical i.e. scientific
context. In everyday talk and thinking we may say that we control something in the environment and that something is possibly controlled also by some other person. But we should know better that we and those other persons are controlling only our or their
own perceptions and nothing in environment. That object or something in the environment OF which our perception is may be the same OF which the other persons’ perceptions are. But we do not control that object or whatever there is in the environment but just
our own perceptions.

We routinely forget that this is a presumption, and we are justified in doing so.

No, we are not justified in doing so if we are scientifically studying “behavior as control of perception�.

It is impossible to argue whether or not the controlled variable is in the environment without forgetting that we make this presumption, and that it is a presumption. If we accept the justification (which we must, in order to do things together,
including arguing, and which we routinely do to survive) then we thereby assert that it is in the environment. But when we wish to identify things in a control theory diagram as a tool of analysis, we remember that this is a presumption, merely the projection
of our perceptions onto the otherwise unknowable environment, and we must acknowledge that it is in the perceived environment, the universe of perception, which we perceive to be shared between and among us, and really out there, largely because of the routine
successes of collective control.

Yes that is right, I agree with this.

I know of no way out of the conundrum other than to acknowledge it. I believe it is foolish to argue about it.

The only way out perhaps is staying strict and careful with our concepts. We must tell when we use every day “control� and when PCT “Control�.

Eetu Pikkarainen

PhD (Ed.), Dos., University Lecturer (in Education)

Faculty of Education, University of Oulu, Finland

Schools in Transition: Linking Past, Present, and Future in Educational Practice

Edited by Pauli Siljander, Kimmo Kontio and Eetu Pikkarainen


https://www.sensepublishers.com/catalogs/bookseries/other-books/schools-in-transition/

                         /Bruce

On Wed, Jun 7, 2017 at 11:33 PM, Martin Taylor mailto:mmt-csg@mmtaylor.net wrote:

[Martin Taylor 2017.06.07.22.48]

On 2017/06/7 8:25 PM, Alison Powers wrote:

Martin - I am confused because you say:

MT: Rick says the controlled variable is in the environment, which I say cannot be true, because in the environment there exists no independent reference variables nor
sources from which they can be determined independently of observation of the moment-by-moment values of the environmental variable itself.

But then Rick responded to me in the PCT Research thread:

RM: The controlled variable is not in the outer environment; rather it is a function of physical variables that are in the outer environment; the function is called a perceptual
function.

I construed that sentence from Rick to be a shot in a different long-standing and apparently irresolvable argument, which I had intended to ignore. I realize there’s no
point in reiterating the fact that the result of applying a function to a bunch of variables is itself a variable, but that’s the nub of the argument in which that sentence was a shot. Rick disagrees – it’s mathematics and therefore just an opinion open to
contradiction.

However, to me he certainly suggests in that sentence that the controlled variable is in the environment, whether it is a function of other variables in the environment
(presumably controlled ones) or should be treated as the result of that function. Certainly the function that defines the CEV is the perceptual function. We have never had any disagreement about that. The question is whether the arguments to that function
are in the environment as he explicitly says they are.

But consider instead Rick’s recent statements about “behaviour”, which provide the context for interpreting the sentence you quote [From Rick Marken (2017.06.06.1225).
I have highlighted a few phrases and sentences. I don’t think I need more than this, though I could go back into the archives and find interactions between us when Rick has argued against me that the controlled variable IS in the environment, quite explicitly.
Yesterday’s message should be enough to make the point:


RM: Saying that “behavior is control” simply calls attention to the fact what we call “behaviors” are both actions and results; in PCT lingo, behaviors are both outputs
and the variables controlled by those outputs – controlled variables. So the behavior called “tying shoelaces” points to a control process where the controlled variable is the state of the laces, the reference state of this variable is “tied” and the outputs
that produce this result are the hand movements the get the laces tied. Moreover, what we see as the output component of a behavior are typically controlled variables themselves and what we see as the controlled variable component of behavior is typically
an output itself. For example, the movements (outputs) used to produce the reference state of a controlled variable (tied laces) are themselves a controlled variable; their speed and direction are the controlled result of muscle forces. And the tied laces
(the controlled variable) that result from those outputs (movements) are themselves outputs that are the means of controlling another variable, the “onness” of the shoes.

RM: So “control” is just a more precise definition of the informal term “behavior”. “Control” refers to the observation of a variable being maintained in a reference state,
protected from disturbance. And this is what we can see is what is going on with the things we call “behaviors”. “Tying shoelaces”, for example, refers to the observation that a variable (the state of the laces) is maintained in a reference state (consistently
brought to the state “tied”) protected from disturbance (the different initial state of the laces, variations in the forces the affect the laces, etc). When you are able to see behavior – any named behavior – as being both output that affects the state of
a controlled variable and a controlled variable itself – you have learned to see behavior through control theory glasses. By the way, this is all discussed in the first 2 chapters of “Controlling People”.


MT. In all of that is there any suggestion that a controlled variable might be a perception? I think not. Everything refers to the controlled variable being a state of
the environment that can be observed by another person. In those two paragraphs, the only reference to perception is in the “P” of “PCT” up front. If Rick had said, for example, in the second highlighted clause “the controlled variable is the [perceived] state
of the laces”, I would have no problem. But he didn’t, and any casual reader might think he meant (and maybe he did mean) the actual state of the laces in the environment.

MT. We all know the form of the control loop, at least in its simplest “canonical” form. We also know that real organisms have limitations such as sensory thresholds, which
mean that any particular value of an external variable gives rise to an uncertain value of the perceptual variable that is produced by its perceptual function (actually a hierarchy of perceptual functions), and we know that neural firings are actually not
a continuous smooth “neural current”. What we also know is that the reference value for a perceptual signal is generated from within the organism, and does not exist in the environment (contrary to what Rick seems to imply in the fourth line of each paragraph).
Control of a perception may not even correspond to control of anything another observer could perceive in the environment, if the perception includes any component from imagination.

MT. It seems to me that regardless of what may be in Rick’s mind (and he agreed with me the other day about Behaviour being the control of perception), the words he uses
can easily lead a reader to conclude that controlled variables exist in the environment. I would like to keep clear that however well the perception corresponds to a state of the environment, it is not the state of the environment, though it is the state that
is controlled. To confuse the two is…confusing.

Martin

[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.

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).�

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…

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

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.

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.

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.

Eetu

Best

Rick

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

[Eetu Pikkarainen 2017-06-13 3]

Rick, the end of your message sounds somewhat like ad hominem. But never mind, it is true that I am studying to understand PCT and you make it hard by using concepts somewhat inconsistently
or at least strangely.

Differentiation between reference state and reference signal is of course reasonable, but the core point is the reference
value and it is only in the reference signal. I think state and value are in this kind of situation synonyms and so you seem to claim that the same reference value is both inside the subject and in the environment. What you see in the environment is
not any reference value/state but rather some value/state which you infer (possibly by using some kind of TCV) to be constrained by a subject who is controlling its/his/her perceptions.

For the conceptual clarity I suggest that the state in the environment which you call confusingly
reference state should be called (by Fred) target state/value. Its definition is: “such a state in the environment which the controlling subject perceives with minimal error�.

Eetu

Lähettäjä: Richard Marken [mailto:rsmarken@gmail.com]
Lähetetty: 12. kesäkuutata 2017 22:53
Vastaanottaja: csgnet@lists.illinois.edu
Aihe: Re: William T. Powers is dead - long live William T. Powers

···

[From Rick Marken (2017.06.12.1250)]

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.

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

RM: “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€?

EP: 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.

RM: Right. The “special” thing that is seen in the environment is that a variable is being controlled (maintained in a fixed or variable reference state, protected from disturbance). For example, we can see that people are controlling for
being upright as they walk over irregular terrain (the disturbances). We infer that they are doing this by controlling (among other things) a perception of the location of their center of gravity)

EP: As part of that inference the observer can do tests and try to disturb the subject’s controlling.

RM: I would say that the inference is the theory of how this control occurs: PCT. The testing that then occurs involves determining what perceptions that are being controlled that are the basis of this observed control: is it perceived
center of gravity, perceived visual orientation with respect to the ground, etc.

EP: What the observer is seeing is not control, but stabilization, see below…

RM: No, if they see a variable being maintained in a fixed or variable reference state,
protected from disturbance , then they are seeing control. Stabilization is not control. In stabilization (as in a mass-spring system) there is a stable (“equilibrium”) state of a variable that could be seen as a reference state but the variable is not
protected from disturbance when it is in this state.

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

RM: The definition of control in PCT is completely in terms of observable variables…“Perception” is not part of this definition; perception is a component of the theory that
accounts for this objectively observable phenomenon.

EP: Perception may not be a part of the definition, but the reference is.

RM: Yes, the reference state is part of the definition of control. The reference state is an observable state of the variable. The reference signal in the PCT model accounts for the constant or variable reference
state of the variable that is observed.

EP: Like perception, also the reference is only inside the subject / organism.

RM: The reference signal is inside the organism; the reference
state is outside the system.

EP: So the definition of control (in PCT) cannot be defined completely in terms of observable variables.

RM: Again, this is “plain and simple” untrue not a lie because I"m sure the error is unintentional).

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.

RM: I appreciate your enthusiasm for PCT, Etau, but I think, at this point in your PCT learning curve, it would be wise for you to take the advice of our recent American winner of the Nobel Prize for Literature and “know your song well
before you start singin’”.

Best

Rick

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

[Eetu Pikkarainen 2017-06-15]

Oops, I have forgotten to use my discussion signature :slight_smile:

I understand I can be irritating and provocative, that’s the way I have found best for learning (not teaching)

I you are used to use the term reference state under the authority of BP then let it be so, but it is anyway confusing because there is only one real reference value and just like the
output also the “reference state� is a consequence of it.

Eetu

image00289.png

···

[From Rick Marken (2017.06.13.1050)]

[Eetu Pikkarainen 2017-06-13 3]

EP: Rick, the end of your message sounds somewhat like ad hominem.

RM: Sorry about that. I didn’t mean to attack you personally but it was probably an unnecessarily rude way to express my irritation at your efforts to teach me PCT.But I suppose now that Bill is gone everyone is an expert on PCT and there are no students so I apologize if I offended you.

EP: But never mind, it is true that I am studying to understand PCT and you make it hard by using concepts somewhat inconsistently or at least strangely.

RM: Sorry. I try my best. But if you really want to understand PCT I suggest that a better way to deal with what you see as my poor explanations of PCT is to ask questions rather than tell me what PCT actually says.

EP: Differentiation between reference state and reference signal is of course reasonable, but the core point is the reference
value and it is only in the reference signal.

RM: See, this is where a question might have been better than an answer.
All variables have values. So both the reference state and the reference signal have values.The value of the reference state of a CV is the observed value of the CV; the value of the reference signal is the value it takes on in the model.

EP: I think state and value are in this kind of situation synonyms and so you seem to claim that the same reference value is both inside the subject and in the
environment.

RM: The reference state has its value(s) and the reference signal has its value(s). They are the values of two different variables, one an observed variable (the CV) and the other a theoretical variable (the reference
signal).

EP: What you see in the environment is not any reference value/state but rather some value/state which you infer (possibly by using some kind of TCV) to be constrained
by a subject who is controlling its/his/her perceptions.

RM: See, this is what irritates me.
Instead of asking me to clarify the concept of reference state you are telling me something about it as though you are the expert in PCT and I am the student. And what you are telling me is wrong, “plain and simple”. When you do this it seems to belie your
intention to learn PCT; apparently you believe you already have learned it and would now like to teach it to me. You can see how that might be irritating.

RM: The fact is that your statement that " What you see in the environment is not any reference value/state" is just the opposite of what is true. In fact, what you see in the environment is the reference state of the CV. This is one of
the most fundamental and important things to understand about PCT. If you don’t like it coming from me, here it is from Bill Powers again:

EP: For the conceptual clarity I suggest that the state in the environment which you call confusingly
reference state should be called (by Fred) target state/value.
Its definition is: “such a state in the environment which the controlling subject perceives with minimal error�.

RM: This is the theoretical explanation of the existence of reference states.
But as you can see from what Powers says above, the reference state of a variable can be shown to exist without any reference to theory. Indeed, it is the objective existence of the reference states of controlled variables that is the reason Bill developed
PCT.

Best

Rick

Eetu

Lähettäjä: Richard Marken [mailto:rsmarken@gmail.com]
Lähetetty: 12. kesäkuutata 2017 22:53
Vastaanottaja:
csgnet@lists.illinois.edu
Aihe: Re: William T. Powers is dead - long live William T. Powers

[From Rick Marken (2017.06.12.1250)]

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.

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

RM: “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€?

EP: 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.

RM: Right. The “special” thing that is seen in the environment is that a variable is being controlled (maintained in a fixed or variable reference state, protected from disturbance).
For example, we can see that people are controlling for being upright as they walk over irregular terrain (the disturbances). We infer that they are doing this by controlling (among other things) a perception of the location of their center of gravity)

EP: As part of that inference the observer can do tests and try to disturb the subject’s controlling.

RM: I would say that the inference is the theory of how this control occurs: PCT. The testing that then occurs involves determining what perceptions that are being controlled that
are the basis of this observed control: is it perceived center of gravity, perceived visual orientation with respect to the ground, etc.

EP: What the observer is seeing is not control, but stabilization, see below…¦

RM: No, if they see a variable being maintained in a fixed or variable reference state,
protected from disturbance , then they are seeing control. Stabilization is not control. In stabilization (as in a mass-spring system) there is a stable (“equilibrium”) state of a variable that could be seen as a reference state but the variable is not
protected from disturbance when it is in this state.

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

RM: The definition of control in PCT is completely in terms of observable variables…“Perception” is not part of this definition; perception is a component of the theory that
accounts for this objectively observable phenomenon.

EP: Perception may not be a part of the definition, but the reference is.

RM: Yes, the reference
state is part of the definition of control. The reference state is an observable state of the variable. The reference signal in the PCT model accounts for the constant or variable reference
state of the variable that is observed.

EP: Like perception, also the reference is only inside the subject / organism.

RM: The reference
signal is inside the organism; the reference state is outside the system.

EP: So the definition of control (in PCT) cannot be defined completely in terms of observable variables.

RM: Again, this is “plain and simple” untrue not a lie because I"m sure the error is unintentional).

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.

RM: I appreciate your enthusiasm for PCT, Etau, but I think, at this point in your PCT learning curve, it would be wise for you to take the advice of our recent American winner
of the Nobel Prize for Literature and “know your song well before you start singin’”.

Best

Rick

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

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