[From Rick Marken (950502.1220)]
Bill Powers (950429.0915 MDT) to Martin Taylor:
If you could just accept that a control system needs NO information
about the world except about the state of its own controlled quantity,
you would see that control depends on properties of the closed loop and
on nothing else.
Martin Taylor (950502 11:30) --
And when have I said anything that would lead you to think I believe
Well, how about this, which follows shortly after your question:
Rick seemed to be making some kind of claim that the control system worked
by magic, whereas I tried to show that it worked by means of the perceptual
But it DOESN'T work by means of the perceptual signal; that's the whole
point. A control system works because of the properties of the closed loop and
nothing else. The properties of the closed loop are the "magic" that makes
the control system work.
In a negative feedback control loop the perceptual signal is controlled; it
is made to be some particular value; it is forced (by the control loop) to
match the reference signal. The perceptual signal in a control loop is in no
position to make the loop work; in fact, the loop is working on it; the
control loop is controlling the perceptual siganl.
To an outside observer it LOOKS like perception (of stimuli, cues, affordance,
information, etc) guides behavior. This is the illusion under which the
behavioral sciences still labor; it is the basis of the lineal causal model
of behaivor: stimulus-->perception-->output--> behavior. I keep speaking to
this issue because I am trying to shout down the Sirens who try to seduce us
with their song "Perception: The control of behavior". Conventional
psychology has already crashed on the rocks; I don't want it to happen to you.