[From Bill Powers (951027.1520 MDT)]
Absolutely the last today!
Bruce Abbott (951027.1230 EST) --
You cite Bowlby:
On the other hand, many behavioural systems have the function of
meeting one or another of these needs; and it is because, if that
species is to survive, those functions have to be fulfilled that
those particular behavioural systems have been evolved.
This is what I'm arguing against. The behavioral systems did not evolve
in order that certain functions essential to survival be carried out.
Evolution does not decide what is needed in order for survival, and then
design a control system to achieve that goal. That is exactly backward.
Because certain behavioral systems evolved, they carry out certain
functions, and to the extent that those functions are important to
survival, those organisms survive. The existence of the control systems
explains the survival, not the other way around. Evolution is not a
cause, but a name for change. Survival is not a goal, but a consequence.
This, I think, is what S. J. Gould is trying to say when he replaces the
evolutionary tree with an evolutionary bush.
I know that Bowlby was trying to make the distinction I'm trying to
make, but he kept falling back on this spuriously purposive way of
talking about evolution and function.
And this:
A difficulty about both 'purpose' and 'aim' is that each tends to
carry overtones of teleological causation. A more serious
difficulty about them, moreover, is that each is habitually used in
ways that fail to distinguish between a system's predictable
outcome and its function--a fatal confusion. For this reason
neither is used in this work.
What's wrong with "overtones of teleological causation?" PCT shows how
reference signals and control systems can accomplish teleological
causation. This is the language Bowlby SHOULD have been using in talking
about control theory. And he SHOULD NOT be talking about evolution as if
it is purposive, unless he has a model showing how it might actually be
purposive. He is not using purposive language where he should, and using
it where he should not.
Look, I've accepted that Bowlby went a long way toward PCT and that he
would have been one of us if he had lived a little later. That still
leaves me a long way from agreeing with everything he said.
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Chris Cherpas (951027.0930 PT) --
If you've seen a simulation that produces cumulative records
typical of FI, FR, VI, FR, and CONC-VI-VI schedules, I am indeed
impressed.
Are you able to compile and run Turbo Pascal source code? Or do you have
a PC on which you could run an executable program? While I won't claim
that every detail is reproduced, or that the model is actually correct,
I do have a model that will behave realistically for the first four
schedules -- and plots a cumulative record to boot! It could use some
more work, and I would be most happy to share the work with someone
else!
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Best to all and good night,
Bill P.