[From Rick Marken (940405.1830)]
I get it! I get it! (I think).
Martin Taylor (940405 15:30) --
I think one of the BIG sticking points in this whole discussion, as I have
often said, is that word "in." Try "the perceptual signal serves as a
channel for information about the disturbance." I don't much like that
wording, but it might reduce the confusion. Information isn't "in"
the perceptual signal, at least not for long, and the better the control,
the less there ever will be "in" the perceptual signal. It's simply not a
repository. The information transmitted through this channel doesn't "get
in the way of control." The faster and better it gets out of the channel
and is used for control, the better control should be, and the less
information about the disturbance will be manifest in the changing values
of the perceptual signal.
This helps me understand a lot because I had a lot of fun as a kid
squirting hoses at kids who looked like they were going to grow up
to become information theorists. Now you (an information theorist yet)
have helped me understand that perception is like the opening to the
hose. The water coming out the end of the hose (in bits per second) is
the information about the disturbance. The degree to which my thumb is
over the opening to the hole represents how well I am controlling the
perception (the opening). The more my thumb covers the hole, the better
I am controlling the perception. But the rate at which the water (in gal/sec)
or information (bits/sec) is coming through the opening is always the same!
Covering the opening completely is like perfect control -- that would
cut of the information (water) completely so it can't happen.
Of course, the information hose has to be one of those "special" hoses
that actually increases the rate at which water comes out as you cover
the opening more and more with your thumb. And, of course, there's
still the pesky problem of finding where the equivalent of the "water"
(information) is in the perceptual signal of a real control system. But
at least now I can see that those budding information theorists whom I
was hosing down were,indeed, all wet.
Best
Rick