Newsgroups: bit.listserv.csg-l
Date:         Tue, 6 Oct 1992 11:00:07 EDT
From:         mmt@BEN.DCIEM.DND.CA
Subject: Re: percept

[Martin Taylor 921096 10:45]
(Bruce Nevin 92106 08:35:57)

>I am troubled by the noun "percept" that you have introduced, Martin,
>and have been using for some time.  Maybe you can clear it up for me.
>
>I know you defined it carefully at the outset, a number of months ago,
>but I'm reluctant to search through disk archives.  (And I don't have a
>Mac with your Hypercard stack!)  It seems to denote something outside an
>ECS to which the perceptual signal within the ECS corresponds.

Interesting comment.  I was not aware of having changed terminology, and I
would have to go back through my postings to see exactly where I have used
the term "percept".  But if I were to use it today in a posting, it would
mean exactly "perceptual signal" (or possibly a stored memory of a perceptual
signal that could be used as a reference signal).  I might use it to refer
to a desired perceptual signal, which would be one that matched a reference
signal, but I doubt that I have used it for the reference signal itself.  I
would not use it to refer to the error signal.  And  I do not have a concept
of a percept as being anything outside the ECS.

This question raises a subtle issue that this question raise, and one that
has supported an ongoing theme for some time.  The question is more or less
"What is it in the outer world that corresponds to the perceptual signal in
the ECS?" I have called that relationship among outer world variables the CEV
(Complex Environmental Variable).  Sometimes I may have spoken of the percept
of the CEV or something of the kind.  There was an exchange with Bill a little
while ago on what he labelled "Three Stages of Satori": (1) I control the CEV,
(2) I control the percept, (3) I control the CEV, realizing it is really the
percept.

The CEV can be described to and possibly observed by a third party, whereas
the percept cannot.  The great problem of The Test comes from the difficulty
of accurately determining what is the CEV for the subject's percept.  That is
the issue that is ongoing with Rick Marken about the statistics of his
area-perimeter study, and by extension the value of statistical analysis in
psychological experiments generally.

The CEVs, being in a mirror world, are at once personal and public.  They form
the link between people, but they are determined by private perceptual
functions that may not be overtly known to the perceiver, and hence cannot
be accurately described to another person.  But the variables and relationships
that are the stuff of the CEV exist in the world (unless you believe in
solipsism), and if I push something that forms part of one of your CEVs, it
alters the corresponding percept.  So in that sense, language sometimes may
lead me to talk as if the percept was in the world, like the CEV that mirrors
it.  But as soon as you want to be precise and technical, the percept (a
present or possible perceptual signal) is in the ECS and nowhere else.

I know that's not all clear, but the whole mirror-world thing is only
gradually becoming less vague in my own mind.

Martin
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