[From Bruce Gregory (2001.0917.1340)]
Rick Marken (2001.09.10.0830)
This post strikes me as very important, but I am having trouble untangling
the threads. Here is my attempt to see how well I understand the points you
No. A perception, in PCT, is defined as the existence of a neural
current in the output of a perceptual function.
Perceptions are _variables_.
So the neural current can take on different values.
Many of these variables are controlled but many are not, at
any particular time anyway.
Fine. That's my experience, too.
A perceptual variable that is _not_
controlled may be the perceptual input to a one-way control system whose
reference signal is set to zero (and the value of the perceptual
variable is less than zero) so that variations in the perception "don't
matter" to the control system; or it may be a perceptual signal that
doesn't enter a control system. But I think the latter would is
unlikely: Why would the nervous system develop the ability to perceive a
variable that it would never have to control?
I'll pass on this because it seems irresolvable.
I think a perception of, say, the sunset, is an uncontrolled perception.
Fine. That makes sense to me as well.
But a sunset is a collection of perceptual _variables_ -- brightnesses,
distances, colors, relationships, configurations -- that _can_ be
controlled in other circumstances, for example, when paining a sunset.
To say that a sunset "is" a collection seems confusing. Certainly the
perception of a sunset can be described in terms of a variety of perceptual
variables. Agreed that these, or related, perceptual variables can be
controlled in other circumstances
I think this whole discussion of whether or not there are controlled and
uncontrolled perceptions would benefit from remembering that
perceptions, in PCT, are _variables_. We don't control "cars", for
example, but variable perceptual aspects of cars: their speed, color,
shape, location, direction, etc.
In general we rarely control the color or shape of cars. We certainly do
control their speed and location of the car we are driving. We also control
the distance between the car we are driving and other cars. The slower the
speed, the shorter that distance can become without us taking corrective
All of these are variables that might
also be controlled when they are _not_ aspects of a car. For example,
you continue to control speed when you get out of the car and walk.
That's a very helpful point.
seen from this perspective I think you can see that it is probably quite
unlikely that there are any perceptions (perceptual variables) that are
not controlled (or, at least, controllable).
I'd be happier if you said "it is quite unlikely that there are any
perceptual variables that are not controllable." That is both clear and
I think the distinction between perceptions and perceptual variables is
very important and might allow us to resolve several past disputes. For
example, the highway patrolman does not control my speed. He controls a
perceptual variable "speed of traffic". I also control a perceptual
variable, "my speed." As long as my reference value for this perceptual
variable does not disturb his ability to control his perceptual variable,
we are unlikely to meet.
In a similar way, different teachers control different perceptual variables
related to order in the classroom. The only way to explore these variables
is by using the Test. Because one classroom is noisy and another is not
does not allow us to infer that one teacher is controlling at low gain and
another at high gain. Again the Test is needed.
Finally there are questions of political correctness. The phrase "I see you
have chosen" means different things to different people. For me it is
equivalent to saying, "I see you have chosen a course of action that
requires me to ask you to leave the room so that others can work without
interruption." For you and Bill the phrase has other connotations. We are
controlling similar, but not identical, perceptual variables.
Most perceptions, in my experience, are uncontrolled. We are, however,
always controlling one or more perceptual variables. It's not so much that
it is all perception as that it is all control of perceptual variables.