# "engineering" perception

**URL:** http://discourse.iapct.org/t/engineering-perception/306
**Category:** CSG1999
**Created:** [October 18, 1999, 7:49pm UTC](http://discourse.iapct.org/t/engineering-perception/306 "1999-10-18T19:49:50Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![Bill\_Powers1](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/b/8e7dd6/32.png) [@Bill\_Powers1](http://discourse.iapct.org/u/Bill_Powers1)
#### Post date: [October 18, 1999, 7:49pm UTC](http://discourse.iapct.org/t/engineering-perception/306/1 "1999-10-18T19:49:50Z")

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[from Mary Powers 9910.11]

One more time to Kim James:

You were not the person who said "yawn, yawn". That was a direct quote from  
Frank Wood. So Powers wasn't saying you were being dismissive, because it  
wasn't you who said that. So if you want to be dismissive back to somebody,  
talk to Wood.

As for your post of 10 October: Powers' model does not resemble Gregory's.  
Or, more correctly in terms of priority, Gregory's does not resemble  
Powers'. Richard Gregory seems to be one of a number of people lately who  
have rediscovered control theory and its application to organisms as well  
as to artificial systems. The problem is that the control theory they are  
talking about is modern "model-based" control thory, which differs in some  
important respects from classical control theory, being digital rather than  
analog, and involving complex programs and vast computations. This is a  
model which cognitive psychologists can feel comfortable with, but it bears  
little resemblance to either classical control theory or to the nervous  
system.

What Gregory's model resembles, as you describe it (which I admit is the  
extent of my knowledge of it), is the Miller, Galanter and Pribram TOTE  
unit of 1960, which Powers feels describes the goings on in a person at the  
9th, program level - but only at that level. Modern control theory seems to  
have been developed along TOTE lines too. But that is nine levels up (or  
in) from where the nervous system interfaces with the external world.  
People do a lot more than cognize programs. You seem to be arguing against  
a view (Gregory's?) that is not much like anything Powers has said.

[continued on 18 October]

This concerns your definition of perception - "a relational state of the  
organism-in-environment closely-coupled system" and so forth. I think you  
are calling the whole circular process "perception" or  
perception/cognition. This closed loop through the organism and the  
environment and back through the organism and so on is what Powers calls  
the control loop. In his scheme, perception is the input side: the neural  
impulses going into the system. A matter of definition. In his case, it is  
an operational definition - a component of a system that is neurologically  
plausible, and that works in simulation and in physical models. For a long  
time there have been good explanations of the external part of the closed  
loop, called, among other things, physics. Perceptual Control Theory is an  
explanation of the internal part, inside organisms. None of this implies  
that there is no real world, but it does assert that all we can know of it  
are perceptions of various kinds - all, except simple intensities,  
constructed internally. And this definition of perception means that it  
is, indeed, in the head.

Which brings me to the post from Monica Lee of 15 October.

I'm sorry that I can't quite visualize from your description what the  
drawings under different conditions actually look like. I do think that  
"drawing a table" involves a different level in the perceptual hierarchy  
from "copying lines", which would imply that any errors would be errors of  
a different kind.

Mary P.