[From Rick Marken (930824.2130)]
I just couldn't resist commenting on Martin Taylor's (930824 15:00)
comment on Tom Bourbon's (930824.1028) comment on Michael Fehling's
(930823 18:40:21) comment.
Similarly to PCT (I think), our model requires that
the organization and its decision making units accomplishes this control in
terms of its interpretations of environmental conditions.
And Tom said:
... an organism
accomplishes control *of* " its interpretations (TB: perceptions) of
environmental conditions," not "in terms of" that interpretation. This is
another significant topic for us to explore.
And Martin says:
I would have read "in terms of its interpretation" as translatable to
"by means of the perceptual input function" rather than "the current
value of the perceptual variable" as you did. If you are right, the
rest of your argument follows, but if I am, he is much closer to PCT
than you allow.
So you are saying that an acceptable way to describe the operation of
a control system is to say that "it is organized to accomplish control
BY MEANS OF the perceptual input function". This sounds completely wrong
to me. Control means maintaining a variable in a fixed or variable
reference state, protected from the effects of disturbance. We know
that the variable controlled by a control system is the perceptual
variable, p, so control means that p = r; the perceptual variable is
kept matching a variable, r, that is a specification of the reference
state of the perceptual variable. The perceptual function, f(), transforms
an environmental variable (or variables), i, into the perceptual variable,
so p = f(i). The statement above implies that f() is the means by which
control is accomplished. But what could f() -- the perceptual function --
have to do with the fact that p=r? The only sense I can make of this
is to assume that you were thinking that the output variable, o, which
is used by the system to keep p matching a potentially varying r and
to resist the effects of disturbances to p, is guided in some way by
the output of the perceptual function -- which is p. So you are saying,
I think, that o = f(i) -- control actions are a function of perception.
This is the way most people (including MOST conventional "manual control"
theorists -- excluding the two that Greg Williams found out about) think
of control -- as an input-output process. This makes sense in terms of
conventional psychological thinking -- which sees perception as the start
of a cause-effect chain that ends with "actions". But PCT shows (both
mathematically AND experimentally) that this model of control is precisely
(and surprisingly) wrong. It is NOT TRUE that o = f(i). In fact, outputs
do not depend on inputs AT ALL; they depend on r and the typically
undetectable disturbances,d, to the controlled perceptual variable:
(1) o = r - 1/g(d)
where g() is the feedback function relating system outputs to inputs.
So the outputs that keep p under control do not depend AT ALL on i or
on a function of i (note that neither i nor f() show up in equation 1).
So it is completely -- exactly -- incorrect to say that control is
accomplished "by means of the perceptual input function". Tom's
statement above was precisely correct -- control systems control an
"interpretation" (the output of f(i), which is p) OF environnmental
events. Control is the control OF perception; there is no control
BY perception. That's what make PCT such a pain for conventional
psychology, which is based on the idea of control BY perception
(even if this control is mediated by complex intervening events).
Unfortunately, control BY perception doesn't happen in control
systems -- not even a little, eensy, weensy bit.