To Chuck Tucker

[From Rick Marken --}

Chuck

Sorry about posting this to the net. I tried to send
this to your personal address it kept bouncing.
Could you send me your address in reply. Thanks

I got your note and the diagram of the basic control
system. There is a small error in the diagram; the
perception line, p, has an arrow pointing INTO the
Input Device Box AND the Compare box -- it should only
point into the Compare box.

I agree with your point -- that it should be obvious from
the model that k.d (and d) cannot be detected in p. But
this is a very hard thing to believe; the IT people were
simply making the reasonable point that something about
p must guide the outputs that lead to control. This is a
very reasonable assumption from a cause-effect point of
view; the fact that it is wrong may be obvious to you --
but it is also obvious that it took a hell of a lot of
effort to convince people of this fact -- and I doubt that
many people are really convinced of it anyway.

Best

Rick