[From Gary Cziko 930906.0315 UTC]
Rick Marken (930905.1700) queries with sincerity:
What is an "encodingist" view? What is an "interactive" one. I think
my view of perception could be called "encodingist" and I'm a card
carrying PCTer.
Let me postpone trying to answer this question directly for a while.
Hopefully an answer will emerge as we grapple with the following.
I believe that perpcetions are signals resulting from
neural transformations of input sensory data: p = f(s). The function f()
determines what variations in s are represented by variations in p. The
magnitude of p can be considered a "code" -- it is simply an analog
neural representation of something about s. You can decode p if you are
given f(). That is, you can determine what sensory state any particular
value of p "coded" by solving s = f-1(p).
I am a bit surprised by this kind of talk since you seem to be taking a
perspective of an outside observer of the perceptual system. Now put
yourself back inside. How can the perceptual system itself know what the
function f is? The only way the function can be derived is by observing
BOTH the perceptual signal and the environmental stimulus which it
presumably encodes. But the perceptual system has no access to the "real
world," no God's-eye view of "boss reality." It has only it's perceptions.
So how could the perceptual signal ever encode anything about the
environment that could be meaningful to the perceptual system? Dot-dot-dot
can encode (stand-in for) the letter "S" for you if you already know what
the code is. But how's you gonna know that dot-dot-dot means "S" when all
you can perceive is dot-dot-dot? Our friend Rene' Descartes used God to
help him out of this one. But as a respectable atheist scientist, you
don't have this luxury.
What the system can learn, however, is that a certain perceptual signal
varies in a certain way or is maintained at a certain value when another
perceptual signal (or reference signal) also varies in certain way or is
maintained at a certain level. That is, we can only learn about our world
by INTERACTING with it. As I believe Heinz Von Foerster said, the world is
a black box. We can only discover its properties by (perceiving ourselves)
pushing, pulling, squeezing and stretching it and perceiving what happens
when we do.
In some respects, my argument here reminds me of one I believe you yourself
used on Martin Taylor concerning the "no information about the disturbance
in the perception." Didn't you point out that the control system has no
knowledge of the output function and therefore could not deduce anything
about the disturbance from its actions used to control the perception?
Let me stop there for now and get your reaction, since this type of
discussion can quickly become too epistemological for me to (be able to or
want to) handle. Am I making sense? Will you now renounce your
encodingist allegiances? You really owe it to yourself as a PCTist.
--Gary (getting in way over my head, but that's OK since that's how one
learns to swim) Cziko
P.S.
ยทยทยท
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