Information in the Perceptual Signal

<[Bill Leach 950218.22:39 EST(EDT)]

NET

While musing this evening, I thought I'd try posting some thoughts on the
'problem' surounding this discussion.

For starters, if we consider then entire process as a 'black box' and
then look at only the Perceptual Signal:

     We can not conclude ANYTHING. We can not even tell if the
     control system is controlling or not.

     The perceptual signal is a 'composite' of anything affecting
     the environmental variable that is the object of perception
     including; all disturbance(s), control system effects and
     various noise sources.

I keep thinking about Martin's assertion "that there is information about
the disturbance in the perception". In the sense that one could look
ONLY at the perception; without knowing anything else other than the
subject signal IS a perception for a control system, then I posit that NO
there is no information about the disturbance in the perceptual signal.

OTOH, as soon as you begin adding specific knowledge about the control
system itself, the possibility of discerning "information about the
disturbance" increases above zero.

As Martin mentioned in discussion with Bill P. and myself some time ago,
it is even possible to 'extract signal information' that is below the
system noise threshold. While this is certainly true such action still
requires some knowledge of system (most particularly in this case, the
nature of the noise sources and signal processing hardware
characteristics).

We (PCTers in general) assume a great deal of knowledge about the control
system in most discussions. We (again PCTers in general) are not usually
concerned with quantitative measurement to within <1%.

As I at least sorta tried to suggest in a previous posting, the sort of
analysis that Martin is suggesting is probably a very long way off.

The disturbance that Martin's assertions in this area cause is most
likely related to the fact that 1) we are unable to apply his analysis at
this time, 2) many people missunderstand the real point in what is being
asserted and thus garner a missunderstanding of simple control system
operation.

-bill