Why Ask How?

CSGnet Archive CSG1993
1

[From Rick Marken (931116.1600)]

Oded Maler (931116 09:30) --

There is a crucial point the PCTers like yourself neglect, and it is
the central point for other people interested in control (engineers,
mathematicians, etc.) You emphasize the question "what is a system
doing", namely what is it controlling for. They ask the question
"*why* does it work (in the real world)?" If you think about it, you
will see that you don't adress this question seriously.

We do address the question "how does it work in the real world?"
rather seriously. I don't really see how the answer to the "how"
question would differ from the answer to the "why" question -- but
I'll take your word for it; you ask "why" it works; I ask "how" it works.

Saying that reorganization takes care of it, does not answer the
question.

That's correct, whether you are asking "why" or "how".

This question cannot be answered analytically (by building a model of a
dynamical system

Then what's left? How to we find out "why" a control system works?
Does it work because there is information about the disturbance in
perception? Very interesting. I guess the problem is that the people
who think that the answer to the question "why does a control system
work?" is "because there is information about the distubance in
perception" don't seem to care about "how" this works. They don't want
to deal with the question "HOW does the perceptual information about the
disturbance result in control?" If they tried to answer THAT question
(by building a model that uses information about the disturbance) they
would find that there is no perceptual information about the disturbance
to be used. All there is is perception. I would imagine that that
would bring the answer to the "why" question into considerable doubt.
But then, people being control systems and all, maybe it wouldn't.

Best

Rick

2

[From Oded Maler (931117 13:30) --

[Re: Rick Marken (931116.1600)]

[Recently I receive CSG-L messages not chronologically ordered,
so maybe I temporarily miss other postings on this thread.]

I have the impression that sometimes you (Rick) are the best
demonstration of feed-forward (model-based and not perception-based)
control system :slight_smile:

But seriously, I'm not sure my point is clearly understood. I make a
distinction between

1) *How* the system works *internally* (controlling its perception).

2) *Why* does the system succeed in doing it in the world, both
internally and externally (apparently achieving "objective" goals in Boss
reality).

--Oded

ยทยทยท

--

Oded Maler, VERIMAG, Miniparc ZIRST, 38330 Montbonnot, France
Phone: 76909635 Fax: 76413620 e-mail: Oded.Maler@imag.fr

3

[Martin Taylor 931117 13:40]
(Rick Marken 931116.1600)

(To Oded Maler, who said I was looking at "why" rather than "how")

We do address the question "how does it work in the real world?"
rather seriously. I don't really see how the answer to the "how"
question would differ from the answer to the "why" question -- but
I'll take your word for it; you ask "why" it works; I ask "how" it works.

Bill Cunningham, in private communication, suggested that I was looking
at "what must be," rather than "why." I tend to agree. The reason I
originally jumped at PCT when I was first pointed to CSG-L was that it
satisfied my understanding that PCT was "what must be" true of living
organisms. That is, that behaviour is the control of perception. The
reason that it must be so can be approached from many angles.

One of those angles is the thermodynamic/information-theory angle. In
thermodynamic terms, the world is too hot for most carbon-based compounds
to last for very long. If one sees such compounds in any quantity, one has
to deduce that in some way they affect their enviroment in such a way as to
reduce their apparent temperature (reduced entropy->information acquired about
the environment that allows them to act so as to stabilize the environment).
That is control, and it is necessarily control of perception, where
perception is taken in the general sense given it in PCT. Here is
one "what must be" that is provided with a "why it must be."

The degrees of freedom argument, within PCT, says that "what must be" is
the co-existence of uncontrolled perceptions with controlled perceptions.
It is an information-based argument. It says nothing (paraphrasing Bill
Cunningham) about HOW these uncontrolled perceptions and controlled
perceptions interchange places over time, but it says they must do so.
Control is a time-multiplexed phenomenon. It "must be so."

Why can it be so? Because the information rates from the world about
things that would severely destabilize the chemistry of the
organism is small enough that the effector mechanisms can (usually) be
time-shared among the things that matter; hence alerting systems.

All there is is perception. I would imagine that that
would bring the answer to the "why" question into considerable doubt.
But then, people being control systems and all, maybe it wouldn't.

Does the above bring either the "why" question into doubt? I think
it demonstrates that "all there is is perception" is a part of "what
must be."

Rick, how often must I suggest to you that the question of segregating
the influence of the disturbing variable on the CEV from the influence
of the output is orthogonal to the question of how much information about
each is inherent in the perceptual signal. The only approach I have read
from you on this whole information matter is based on the fact that one
cannot segregate the two influences without having other information.
You repeat it over and over, to the point of boredom.

That is a point on which we have agreed from day one. You have never
made any attempt to show why it should be relevant to the question of
how much information about the disturbing influence is in the perceptual
signal. But if I do not accept that the two (independent) questions are
in fact the same question (which they are not), I am said to reject the
PCT view of the world. That's your model of my perception, not my perception.

Martin