Brain Theory and PCT

[From Rick Marken (960302.2020)]

John E. Anderson (960301.0955) --

I wonder if one significant difference [between PCT and other brain
theories] is that PCT supposes the entire nervous system to be a
hierarchy of control systems, whereas mainstream biological control
theories mostly involve only motorsystems. Am I right about that?

It doesn't seem to me that that's the crucial difference. It seems to
me that the crucial difference between PCT and other brain theories is
that the latter don't take seriously the _fact_ that the brain and
nervous system (NS) exist as part of a closed loop that goes through
the environment. That is, the fact that:

  environment -->brain/NS -->
       ^ |




The implications of this simple fact are as devastating for most
conventional brain/NS models of behavior as they are for functional
models of behavior (like those developed in the social sciences).
The main implication of this fact, of course, is that the brain/NS
is a device that controls its own input, not its output.

Many biological control models with which I am familiar are applied
under the assumption that the brain/NS controls output (efferent
neural activity) not input (afferent neural activity). So the control
model is applied in a way that makes it seem like output is the controlled
variabe and that input (feedback) exists only to trim up this output.
Biologists (like psychologists, sociologists, cyberneticists, etc) just
don't yet seem to take it for granted that the brain controls what comes
into it, not what goes out from it. Therefore, they don't bother trying
to determine what inputs the brain controls. Ah well.