[From Rick Marken (921020.0930)]

Bill Powers (921013.0930) --

It strikes me that one problem with "residuals" and all that is simply

that the wrong model is used (as you say). Is there anything to

prevent you from doing statistical manipulations using a closed-loop

model instead of an open-loop one? In fact, isn't that pretty much

what we do, although informally? We're trying to fit a linear model to

the data to obtain the minimum least-squares error of prediction,

aren't we? The only difference is that our linear model embodies a

closed loop.

Yes. As I said to Martin, I think it would be great if he could show

HOW he would go from observation of the data to modification of the

model. My impression (which Martin has yet to dispel) is that Martin

was suggesting that you COULD improve the control model by analyzing

the data in terms of an open loop model (and Martin's statistical

model IS an open loop model). If Martin had something else in mind,

then I wish he would clear it up for me. As I said, I think it would

be an enormous (and, I think feasible) contribution to PCT if he

could develop an analytic technique for going from discrepencies between

model and actual behavior to revision of the parameters of the closed

loop model to improve the fit.

Wayne Hershberger (921010) --

Perception is NOT simply a process of

transporting a representation of some putative conceptual reality

comprising one end of the dipole (the environmental pole) into the

other end (the organism pole). Such a conceptualization

(representationalism) begs the fundamental question of perception,

which is the realization of the perceptual world in the first

place.

What is your model of perception, Wayne?

Here is my model:

EV --->S--->PF--->PS

where EV is an evironmental variable, S is a sensor, PF is a perceptual

function and PS is a perceptual signal. The EV is known only in terms of

our models of physics. But whatever EVs REALLY are, they impinge on S (based

on our models of physiology) which transforms the EV into neural signals

(the physiological model again) that enter a neural netork that acts as

a computation device (PF) that converts the input neural signals into

an output neural signal, the perceptual signal (PS) -- all this is based

on the physiological model. I imagine that it is PS that IS the experienced

perception (this is the PCT mind model). In your example of "diagonal

movement", PS IS the perception of diagonal movement -- constructed

from the sensory inputs that are ultimately caused by the horizontal

and vertical EV movements. What else is needed here -- other than

the delineation of how PS results from EV -- ie. other than the model

of PF and S? What is your model of perception? How does it work?

Gary Cziko --

Thanks for sending the note to Ari. It was very clear and helpful

as usual.

By the way, I have not heard a peep from Psycholoquy about my Blindmen

paper. Better start thinking about the next place to send it.

Best regards

Rick

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Richard S. Marken USMail: 10459 Holman Ave

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E-mail: marken@aero.org

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