Negative feedback, exploring control

[From Rick Marken (931217.1100)]

Cliff Joslyn (931217 10:12) to Martin Taylor --

could you please lay out in
mathematical detail the simplest occurence of negative feedback in
natural systems?

Thanks, Cliff, for adding a second voice to my request for a
description of a non-controlling negative feedback system (I asked
specifically for a description of the negative feedback re-
lationships in a vortex, but any non-controlling negative feedback
system will do). I told Martin that I would settle for a diagram but
math would be fine -- if it doesn't go too far beyond algebra and
elementary calculus.

Perhaps a private reply would be in order.

I want to see it too. So I vote for putting it on the net.

Chuck Tucker (931217) --

I would suggest that instead of trying to relate PCT to CT
one can see the difference between the two approaches by
examining a detailed description of one act that you engage
in on a daily basis (e.g., making a cup of coffee, getting a
glass of juice, getting in and driving your auto out of the
driveway, dressing yourself)

Remember, PCT is a model of human
experience and it becomes very difficult to understand or
critically evaluate without some experience to discuss.

Excellent points, Chuck. We are living in the best PCT lab of
them all -- the world of our own perceptions. In fact, my
"Hierarchical behavior of perception" paper (now available to
the world in the Fall, 1993 issue of "Closed Loop") is about
exactly the point you make; the term "behavior of perception"
refers to what control looks like from the point of view of
living control systems -- us. Most reviewers "balked" at the
title of the paper right off the bat, which is not that surprising;
the title could really only make sense to someone who understands
HPCT; that is, someone who understands the very point you are
making. Unfortunately, you were not one of the reviewers.