[From Dag Forssell (990226 18:00)
From John Appel
Rick is correct , BCT is a recipe; a theory of how to do things, such
as cure patients with mental disorder. I believe this meaning of theory
is scientific. Please correct me if I'm wrong. Perhaps the term a
theoretic "method" of doing things would be more dignified.
John, I have been reading some of the discussion of BCT. I am sure that to
many in the life sciences, the meaning of theory as recipe or prescription
is "scientific."
To people in the physical sciences, this is a bad joke. The advocates of
PCT are promoting a model, a physical mechanism, that "behaves" by itself
just like living organisms do and thus explains what behavior is and how it
works with a rigor that is typical of the concepts and practice in the
physical sciences.
As long as people in the life sciences agree with your view of what is
scientific, they will stay stuck at a level of "science" that is medieval
at best, compared to the physical sciences.
I think that a basic problem in discussing this is that most people, and
certainly social scientists who avoided "techie" subjects in school, have
no idea what is meant by "theory" in the physical sciences -- sciences that
are totally responsible for the rapid progress mankind has made in the last
350 years.
I'll attach a post by Bill Powers that bears on this subject. When you
consider what Bill expressed here, you may begin to understand Tracy's
not-so-polite criticism of a few days ago, and to understand why PCT
scientists may not consider BCT to be worthy of the label "theory" in the
first place.
Best, Dag
···
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Date: Sat, 17 Sep 1994 08:31:54 -0600
From: "William T. Powers" <POWERS_W%FLC@VAXF.COLORADO.EDU>
Subject: Re: Experience, Reality, and HPCT
[From Bill Powers (940917.0600 MDT)]
Hugh Petrie (940916.1000 EDT) --
Well, you sucked me in at least a bit. I hope the very limited time I
was able to give this is of some help.
As I expected. Yes, we put some experiences in the role of evidence, and
others in the role of theory. That's the distinction I wanted, but
couldn't say.
I'm going to ramble through some thoughts about theory and observation,
the two kinds of experiences we're been talking about. Skip to the next
post if you're getting bored with this subject.
Theory, as I see it, purports to be about what we can't experience but
can only imagine (neural signals, functions like input, comparison,
output functions, mathematical properties of closed loops), while
evidence is about what we can experience. Both theory and evidence are
perceptions, but the way we use these perceptions in relation to each
other puts them in different roles.
In the behavioral/social sciences, the word "theory" seems to mean
something else: a theory is a proposition to the effect that if we look
carefully, we will be able to experience something. A social scientist
can say "I have a theory that people over 40 tend to suffer anxiety
about their careers more than people under 20 do." The theory itself
describes a potentially observable phenomenon. The test is conducted by
using measures of anxiety and applying them to populations of the
appropriate ages. If we observe that indeed the older population
measures higher on the anxiety scale than the younger, we say that the
theory is supported -- or, as some would put it, the hypothesis can now
be granted the status of a theory that is consistent with observation.
This meaning of theory leads to the popular statement that a theory is
simply a concise summary of, or generalization from, observations. That
definition has been offered by quite a few scientists past and present.
I think it misses an essential aspect of science, the creative part that
proposes unseen worlds underlying experience. Before the "unseen worlds"
definition can make any sense, however, it is necessary to understand,
or be willing to admit, that there is more to reality than we can
experience.
If reality is exactly what we can experience, then there are no unseen
worlds and in ways obvious or subtle every theory is just a way of
describing experience. Our senses and measuring instruments indicate to
us the state of the real world. A properly-constructed and tested
theory, therefore, cannot be false. The only way it might be false is
for some error of observation or description to be made, or for the test
to contain some internal error or inconsistency.
It is this view that leads some scientists to take a rather self-
congratulatory view of science. A scientist is simply someone who has
learned to describe and generalize correctly. If no mistakes have been
made in observation, description, or method of generalization, then the
theory that summarizes these results must be correct. The personality or
the wishes of the scientist play no part in this process; truth is
independent of the observer.
It is this view, I think, that leads to the Gibsonian approach to
perception. To maintain this view, it is necessary that what we perceive
of the world be a true representation of the world. So by hook or by
crook, we must find a way to show that we, as observers, look _through_
our perceptual systems at the real world. The existence and the
functions of human neural perceptual systems cannot be denied. But to
accept what seems to be the case at face value would mean that we
perceive only an interpreted world, a partial view of the world, or a
projection of the world through unknown transformations into the space
of experience. This, in turn, would mean that all descriptions of the
world are functions of human nature, and thus that all theories about
the world are human theories, not ultimate truths. And it would mean
that the phenomena we experience are related to the properties of the
real world in ways that we can't directly perceive. This is exactly the
conclusion that the Gibsonian approach is intended to deny.
More to the point, the implication would be that some elements of our
theories are not really, in some subtle way, reducible to reports of
observations, but are _made up_ by human imagination. It would mean that
the concept of "an electron," for example, amounts to an _imagined
observation_, with no justification other than that assuming its
existence leads to consistent explanations of experience. If this were
admitted, the result would be to make science much less secure in its
claims to logically-derived knowledge about the real world.
Some scientists know this; others vehemently deny it. Richard Feynman,
for example, knew it. When he was asked how he arrived at his diagrams
showing particle interactions, he said "I made them up." There were
physicists who considered this a flippant answer, consistent with
Feynman's reputation as a joker. But Feynman was quite serious. Particle
physics, he said, is a game we play. It takes a sense of humor to admit
that.
This same dispute underlies the controversy over whether the Heisenberg
uncertainty principle describes a true uncertainty in nature itself, or
a limitation on our methods of observing nature. If you assume that
reality consists exactly of what we can observe about it, then
uncertainty is an aspect of reality. If you assume that there is a
reality independent of, and perhaps quite different from, our
observations of it, then you leave open the possibility that nature is
regular but our observations of it are uncertain. This was Einstein's
view. I say you "leave open the possibility" because in the latter view,
there can be no question of verifying the causes of the uncertainty; all
we can do is make up possible properties of the world which, if they
existed, would account for our observations. There is nothing to prevent
our imagining that the world itself is uncertain, but that does not
prove that it is. It proves only, at best, that making that assumption
leads to a consistent view of the observations, an ability to predict
particular observations with some degree of accuracy.
In PCT there are observations and there are theories. When I attempted
to describe levels of perception, I was trying to describe observations,
how the world seems to come apart when analyzed and how these parts seem
to be related to each other. There is no theory intended in these
proposals. It seems to me that when I see a relationship, I also see the
things that are related, which themselves are not relationships. I could
not see any relationship if there were not things to be related, yet I
could see any of those things (events, transitions, configurations,
sensations, intensities) individually, not in relationship to anything
else. The only question I have is whether anyone else in the universe
experiences the world in the same way. Either they do or they don't;
we're talking observation here, not theory. If these are truly universal
classes of perception, then every undamaged adult human being should
report the same elements of experience, and the same dependencies.
Again: either they do or they don't. That is a question of observation,
not theory.
The theoretical aspect of PCT comes in when we try to explain why it is
that the world of experience is organized in this way (if, in fact, my
experiences are like anyone else's). That's when we start talking about
input functions and signal pathways and control systems, none of which
has a direct experiential counterpart. Of course in theorizing one tries
to imagine hidden aspects of the system that might, one day, actually be
observed. But today, at the time the theory is proposed, we do not
observe them. We can only imagine them. And no matter how much
verification the theory receives from future observations, there will
always be a level of description at which we can only imagine the level
that underlies it.
The same interplay between theory and observation is involved in
experiencing control. You do not need a theory in order to hold your
hand in front of your face and deliberately will the hand to assume
various configurations. Nor do you need a theory to tell you that what
you will is very closely followed by what you then experience your hand
doing. You don't need a theory to tell you that when you grasp the knob
on a door, your intention is for the door to take on an appearance other
than the one you are now experiencing. These are the facts, the
phenomena, that we need a theory to explain.
The theory of control offers an explanation in terms of perceptual
signals, closed causal loops, and mathematical properties of such
systems. These entities, while perfectly experienceable in the mind, are
not the experiences to be explained. We are saying that IF such an
organization existed in the nervous system, THEN the experiences we are
trying to explain would follow. The theory proposes the existence of
entities in the world hidden from direct experience; perhaps not all of
them hidden forever, but certainly hidden now.
The most important part of such theories is that they not only account
for what we do experience, they predict experiences we have not yet had.
The models of PCT are adjusted so that in simulation they behave in the
same way as the particular instance of control behavior we're trying to
explain. But once the model is constructed, we can vary the conditions
that, hypothetically, affect it, and strictly from the properties of the
model make predictions about how the real system would behave under
those changed conditions. This is where the power of modeling shows up;
not in its ability to fit the behaviors we observe, but in its ability
to predict how behavior will change when we alter the conditions
presented to the real system. We can fit a model to the hand motions
involved in tracking a target moving in a triangular pattern, and then
using the best-fit parameters predict very closely the hand motions that
will occur when the target moves in a random pattern, and when a second
random disturbance is applied directly to the cursor in parallel with
the effects of hand motion.
I think that one main reason for the misunderstandings that occur in the
life sciences about control theory is that this kind of modeling is
essentially unknown to most practitioners. The idea of proposing a model
that is more detailed than our observations, and then using this model
to predict new observations under new conditions, does not appear in
textbooks of psychology, sociology, psychotherapy, or related sciences.
It is an idea with which engineers are familiar from their earliest days
in college, but only where engineering has encroached on the life
sciences does it appear in relation to the behavior of organisms. This
method is almost the diametric opposite of generalization; instead of
deriving general classes of observation that include actual
observations, the method of modeling proposes the existence of more
detailed variables and relationships below the level of observation,
from which observations can be deduced. I have heard the term
"hyothetico-deductive" used in situations that make me think of
modeling, although I'm not sure that is what was intended.
Honestly, I'm almost finished.
Now think about what happens when a person who has never heard of the
method of modeling comes up against PCT. To this person, the diagrams of
PCT are simply diagrams of observations. The arrows show how one event
leads to the next event. If this diagram describes any particular
behavior, then it can be accepted as a theory (or not -- people quite
often draw different diagrams, because they "have a different theory").
But such a person does not see what we see: a diagram of a specific
physical system, connected in a certain way, _which we can't directly
observe_. This person doesn't realize that what we can see is supposed
to arise from the operation of the diagrammed system, not that it is
supposed to be represented by the diagrammed system.
When, some day, the Center for the Study of Living Control Systems goes
into operation, one of the introductory classes that must be taught
there will be an introduction to modeling. It is obviously possible to
teach what modeling means; all engineering students learn it, although
nobody ever tells them what they are learning. They pick it up from
seeing it done and learning the mechanics of doing it. They learn by
osmosis the difference between describing the behavior of a system and
describing the organization of a system that can produce that kind of
behavior (as well as many other kinds). I think this can be taught
explicitly, and that by learning it, students will not only come to
grasp the meaning of PCT as it applies to human behavior, but will
discover that they can probably come up with better models than their
mentors managed to build.
--------------------------------------------------------------------
Wordily,
Bill P.
New area code Feb 13, 1999!
Dag Forssell
dag@forssell.com, www.forssell.com
23903 Via Flamenco, Valencia CA 91355-2808 USA
Tel: +1 661 254 1195 Fax: +1 661 254 7956
)Bruce, Rick, Dag, and