PCT: selectionist? (from Chris Cherpas)

[From Chris Cherpas (960408.1534 PT)]
    [re: > Bill Powers (960407.0915 MST)]

Now I have managed to get you AND Chris annoyed with me.
I'm considerably annoyed myself, and I guess it shows.

I doubt if I could ever be very annoyed with you (maybe Rick,
the CSGNET analogy to Huxley -- in the role of Darwin's "bulldog").

Since I've done EAB work, and have now been exposed to PCT,
I intuitively read something like, "behavior Y is reinforced
by some property of X" as something like "behavior Y probably
controls some property of X." It may not be the _same_ presumed
property, but I sense that such properties are at least in the
same neighborhood.

Both kinds of statements fit a general view that behavior is
an evolutionary process. Apparently, PCT is not concerned with
any evolutionary processes _while_ a system is successfully controlling.
It is only when control is lost (OK, yields to a reorganization
control system?) that variation and selection are considered
to be relevant. Leaving reinforcement aside, could anyone help
me with understanding if this is the case -- i.e., that _within_
a control system, there is no variation and selection? If so,
what are the variations, what's the unit of selection, and what's
doing the selecting?