[From Bruce Gregory (990812.2129 EDT)]
Bruce Nevin (990812.2118 EDT)
Does this not suggest that control of your safety and survival is at a
higher level of the hierarchy than control of (a) whatever
you were doing
when you noticed the threat and (b) whatever you started
doing as means of
reducing the threat?
No (if the gain is what is important). Yes.
Bruce Gregory
[From Bill Powers (990812.2054 MDT)]
Bruce Nevin (990812.1103)--
Of course. But one perfectly permissible value of a reference signal is
zero.
You assume that to "have a value" is equivalent to having a _non-zero_
value, or a value high on a scale. But reference signals can pertain to
unpleasant things and have a value of zero (strongly controlled for).[...]
My reference signal for pain has a value of
zero. I would prefer to leave it that way.Can you explicate the difference between a reference value of zero
controlled with high gain in the output function "(strongly controlled
for)" and a reference value of zero resulting in no control (don't care).
Are you saying the gain makes the difference?
Nice catch, but I don't think I'll going to solve the problem for you.
Assume that there is a solution, and work it out. Remember, when I said
that a zero reference signal turns off a control system, I referred to a
specific kind of control system, a one-way control system with an
excitatory reference signal and an inhibitory perceptual signal. In many
cases we have apparent two-way control, which of course has to be
implemented by using two one-way control systems. When you have two-way
control, what we think of as "the" perceptual signal, "the" comparator,
"the" output function now have to be considered as pairs of functions in
systems which operate like a push-pull audio amplifier: if a signal
increases in one system it must decrease in the other.
That's a pretty broad hint, but I'll leave the rest to you. Oh, I'll give
you one more. The biceps and triceps represent output functions of opposing
one-way control systems. When the elbow is being held at a specific angle,
_both_ muscles are usually in tension; this effect is called muscle tone.
The reason there is muscle tone is so that there will be no position where
both control systems are turned off at the same time.
See what you can do with that.
Best,
Bill P.
[From Bill Powers (9908712.2105 MDT)]
Bruce Gregory (990812.1715 EDT)--
I have no problem seeing how
an upper level control system can set the reference of a lower level
system to zero and hence shut it off. My problem is I don't know how we
stop controlling one input and start controlling another _in the absence
of such an upper level system_.
The only place you have to worry about that is at the highest level. At all
other levels there are higher systems adjusting the reference signals of
the lower systems. Rick's spreadsheet demos show that many control systems
can be operating at the same time at a specific level, yet all can be
maintaining close to zero error -- even though they act by sending
reference signals to a common, shared set of lower-level systems.
At the highest level, the only way to eliminate conflict among
simultaneously-acting control systems is by experiencing the consequences
of conflict and thus starting reorganization. Since at the highest level
there are no higher systems to turn reference signals on and off, all the
systems have to be compatible with each other to avoid conflict, because
they must all be active at the same time. (I just thought of that, as a
result of your question).
Even with all systems at the highest level turned on all the time, we can
still have context effects, so that some of the systems experience zero
disturbance while others are being subject to disturbances. My parent
control systems are not experiencing much error in situations where, for
example, my mathematician control systems would be active. The perceptions
involved in parenting simply aren't there when I'm working on a math
problem. Of course if I try to do that at home, with a new baby hollering
in the next room, the two activities are likely to come into conflict: it's
hard to be a mathematician and a parent at exactly the same time. One
outcome of the ensuing reorganization might be that I stop trying to be a
mathematician at home.
It may be that the system with the
highest gain gets to be in charge. When I see a threat to my safety,
controlling _that_ input takes precedence over inputs controlled at
lower gain. Does this make sense in the standard model? Is it reasonable
to assume that we are always controlling the input associated with the
highest gain?
No, I think that's a description of a system that's close to a debilitating
level of internal conflict. The ideal solution is for all active control
systems to be perceiving and controlling independent dimensions of the
whole of experience at the level in question. This would be the ultimate
outcome of reorganization, because when control systems start interacting
with each other, the range of control is reduced and the energy used for
control is increased. This would reflect as an increased level of intrinsic
error and an increased rate of reorganization.
Remember that there is no problem for systems at levels lower than the
highest level. The higher-level system will be reorganized until it never
issues conflicting reference signals, so the lower systems never have to
"prioritize" or "choose" or "override" and so on. If a higher system sees a
threat to your safety (presumably at the logic level), it simply turns off
some control systems and turns on others appropriate to handling the
threat. Then, when the threat is past, it turns the original control
systems back on. In a hierarchical model, you don't have to try to make the
active systems themselves turn each other on or off, or override each
other, all of which leads to confusing models, not to mention putting
unwanted properties in them. The higher control systems take care of all that.
In fact, the ability of a hierarchical model with many systems at each
level to maintain control of multiple variables at the same time is rather
astonishing, until you study a working model and begin to understand just
how this is accomplished. There's nothing to prevent a person from
continuing to cook dinner and mind the baby while dialling 911 to report a
possible prowler, at the same time satisfying many goals at levels both
higher and lower.
Best,
Bill P.
[From Bill Powers (990812.2149 MDT)]
Bruce Nevin (990812.2118 EDT)--
Gregory:
When I see a threat to my safety,
controlling _that_ input takes precedence over inputs controlled at
lower gain. Does this make sense in the standard model? Is it reasonable
to assume that we are always controlling the input associated with the
highest gain?
Nevin:
Does this not suggest that control of your safety and survival is at a
higher level of the hierarchy than control of (a) whatever you were doing
when you noticed the threat and (b) whatever you started doing as means of
reducing the threat?
Not at all. It could imply that some system (presumably at the logic level)
has decided that it is more appropriate now to control for what we, at our
leisure, label "safety and survival" than it is to continue controlling
what you were doing before. This does not imply any direct hierarchical
connection between "safety-and-survival" and "what you were doing before."
This could involve nothing more complex than unplugging the TV when you see
an electrical storm approaching, instead of going on watching the show.
Watching the TV is one activity; unplugging it is another. Both are being
selected by higher-order systems. Some higher system, like a logical one,
decides that now we are going to stop watching the TV, and we are going to
unplug it, because of concerns that neither the watching nor the unplugging
subsystems know anything about.
When you're playing around with situations like this, you have to be very
careful about what you mean by "I", when you say "I" do something. You are
modular, and the modules are what do the acting and the selecting and the
deciding. There isn't any one I in the middle doing everything. There is an
I observing, but many agents acting.
Best,
Bill P.
[From Bruce Nevin (990812.2118 EDT)]
At 05:16 PM 08/12/1999 -0400, Bruce Gregory wrote:
[From Bruce Gregory (990812.1715 EDT)]
I don't know how we
stop controlling one input and start controlling another _in the absence
of such an upper level system_. It may be that the system with the
highest gain gets to be in charge. When I see a threat to my safety,
controlling _that_ input takes precedence over inputs controlled at
lower gain. Does this make sense in the standard model? Is it reasonable
to assume that we are always controlling the input associated with the
highest gain?
Does this not suggest that control of your safety and survival is at a
higher level of the hierarchy than control of (a) whatever you were doing
when you noticed the threat and (b) whatever you started doing as means of
reducing the threat?
Bruce Nevin
[From Bruce Gregory (990818.1013 EDT)]
Bill Powers (9908712.2105 MDT)
In fact, the ability of a hierarchical model with many systems at each
level to maintain control of multiple variables at the same
time is rather
astonishing, until you study a working model and begin to
understand just
how this is accomplished. There's nothing to prevent a person from
continuing to cook dinner and mind the baby while dialing
911 to report a
possible prowler, at the same time satisfying many goals at
levels both
higher and lower.
You will be relieved (amused?) to learn that I am finally beginning to
understand HPCT and the role of reorganization. The fact that it has
taken this long is not a reflection on your statements (or Rick's) which
have been (and continue to be) models of clarity. It rather reflects the
point of view I adopted from which to listen to those statements. I
think a similar process occurs when people try to understand principles
such as Newton's Laws. You can't imagine how to understand them
differently...until you do.
Bruce Gregory
from Phil Runkel on 19 aug 99
On Wed, 18 Aug 1999, Bruce Gregory wrote a note of appreciation to Bill
Powers, saying:
You will be relieved (amused?) to learn that I am finally beginning to
understand HPCT and the role of reorganization. ... You can't imagine
how to understand them> differently...until you do.
Your note, Bruce, gave me warm feelings of brotherhood, since I have had a
few moments of epiphany like that myself.
--Phil R
[From Bill Powers (990820.0007 MDT)]
Bruce Gregory (990818.1013 EDT)--
You will be relieved (amused?) to learn that I am finally beginning to
understand HPCT and the role of reorganization.
All of those, plus envious. New understandings are one of life's great
joys, aren't they?
Best,
Bill P.