[Hans Blom, 971125b]
(Bill Powers (971124.1034 MST))
Ah, so you do not like to consider yourself in the role of student
with respect to me. I thought as much.
For a while, I considered myself a student of yours -- or rather as
someone studying PCT. That was a while ago, though.
Long time ago, when I was a student, I already realized that my study
for a subject was finished as soon as I started to discover errors,
incoherencies or inconsistencies in a teacher's presentation. That
was invariably the sign that I had grasped the subject matter. Now
again.
What I learned from you was not control theory; that was a familiar
subject to me. What I learned from you was -- how to call it -- a
kind of metaphysics, a call to "go up a level" and ponder the
question "What if I considered _myself_ to be a control system?".
That call fell in fertile earth: for a long time I had admonished my
engineering students not to talk about "control systems" but about
"autonomous agents" who had their own channels of perception, their
possible ways of acting, and -- if the design was to be useful -- the
"intelligence" to understand what their user expected. Especially in
the context of patient monitoring and clinical control systems this
kind of anthropomorphizing proved to be a fruitful avenue: doctors
and nurses have more important things to do than to keep adjusting
control settings; the system _itself_ ought to know what to do when.
Your admonishment induced me to start to compare the behavior of
control systems of all types with that of humans. Even though I never
accepted the thesis that organisms _are_ control systems (in science,
we're usually better off without that verb), I wondered and pondered
which analogies ("models", to use a loaded term) could be fruitful to
enhance understanding of both control systems and humans and which
not.
Given the fact that my understanding of control was different (more
extended, if I may humbly say so 
from yours, my comparisons and
conclusions were different from yours as well. That frequently
introduced misunderstandings. Incorrigible ones, too, it appears. So
be it.
I have no problem with assuming that role when learning something
new from someone else. So I guess your problem is not my problem.
Uh? That depends on whether you _want_ to learn something new, as you
know ;-). Your knowledge of control apparently stems from the 1950's
or so. Control theory has advanced in the 50 years since then; both
our analyses and our syntheses are far more detailed and accurate
now. Yet I have seen no signs that you want to learn about what
control theory is and can provide now; it appears that you are
satisfied with what you know about control -- servo theory -- and
don't want to learn more. That makes communication difficult. And
that's, I guess, why the current control engineering community isn't
much interested in PCT.
Is this discussion group a vehicle for "teaching" PCT rather than
for conducting scientific discussions? If so, goodbye!
You can't discuss PCT until you have learned what I (and others)
have to teach about it.
About what, specifically? About control? There isn't anything that I
can learn from you in that knowledge domain. You may never have seen
it in quite this light, but -- to a control engineer -- this plea
comes across as saying "Go back to the 50's; it was good enough for
me; it ought to be good enough for you". It isn't. PCT has seen no
real advances since you published your book in 1973. Modern control
theory might provide the impetus to carry it further. But I only
encounter enormous resistance there...
This doesn't mean you have to accept it; it does mean that you have
to acquire more than a superficial understanding of it.
Of what, specifically? Sometimes it appears that you're not content
with someone understanding the "objective" subject matter such as the
formulas, but that you are content only if others repeat your
interpretations. There is, however, a whole new and more extended
(control) language in which those interpretations may be expressed
much more precisely.
If you can't temporarily take the role of learner until you know
what you're talking about then my reply is, good riddance.
Been there, done that. Somewhen, however, one has to let go of one's
teachers and walk one's own path. It seems the moment is overdue...
Goodbye, it's been nice talking to y'all.
Greetings,
Hans