Trading, evolving

[From Bruce Abbott (970730.1105 EST)]

Rick Marken (970729.1500 PCT) --

I think you must have missed the central point of Bill's
(970729.0606 MDT) description of the control theory model
of evolution. . . .

etc.

No, I didn't. That was a nice reiteration of Bill's proposal and what you
see as its advantages. But I did not see where you addressed _any_ of the
four points I rasied. I think you must have missed them, so for your
convenience they are reprinted below:

_Point 1_

There is nothing in Darwin's theory that precludes there being a linkage
between the environmental stresses an organism experiences and the fidelity
of its reproductive mechanism. Stress-sensitive variable-rate mutation, if
it exists (and there does appear to be evidence for it in some cases) would
not present an alternative to Darwin's theory but an elaboration of it, an
additional factor contributing to genetic variation.

_Point 2_

The view you propose is not Lamarkian, which states that changes in an
organism's physical structure acquired through use are somehow passed on to
its descendants. Random changes in genes due to stress don't qualify, as
these are simply random mutations.

_Point 3_

Lamarkian evolution has been submitted to better tests than the
ill-conceived tail-cutting experiment, and failed.

_Point 4_

This is not a new idea. It isn't new with you, and it isn't new with me
(much to my disappointment).

I'd like to see a point-by-point refutation, if you can manage it.

Regards,

Bruce

[From Rick Marken (970730.1000 PCT)]

Bruce Abbott (970730.1105 EST) --

I'd like to see a point-by-point refutation, if you can manage it.

Oh, all right. It's so much fun to see you posting again I
can hardly resist.

_Point 1_

...Stress-sensitive variable-rate mutation, if it exists...would
not present an alternative to Darwin's theory but an elaboration
of it, an additional factor contributing to genetic variation.

Stress-sensitive variable-rate mutation is not the essense
of the control theory proposal. The essense of the proposal is
that organisms have genetically set references for the state of
certain "intrinsic" variables -- variables that are measures of
things like the accuracy of cell replication. When the actual
states of these variables differ from their reference states there
is "stress" (error) that leads to mutation. The result of mutation
is changed phenotypes. These changes have some influence on the
state of the intrinsic variables -- closing the loop. If this
influence is one that brings the intrinsic variables closer to
their references the stress (and the chance of a new mutation)
is reduced. This is a closed-loop control process, occuring over
generations, that controls intrinsic perceptual variables; stress-
sensitive variable-rate mutation is only one-half of this closed-
loop process. The part of this process that is not part of the
Darwininan model is the reference specification for intrinsic
variables.

_Point 2_

The view you propose is not Lamarkian

So? This point doesn't even need refuting. The control theory
view is what it is; it doesn't suffer from not being "Lamarkian".

_Point 3_

Lamarkian evolution has been submitted to better tests than the
ill-conceived tail-cutting experiment, and failed.

PCT is not Lamarkian (according to Point 2) and Lamarkian evolution
has been tested and failed (Point 3). I guess I have to wonder what
I am supposed to refute here? I think Point 3 would have been
much stronger if you had said "the control theory model of
evolution has been submitted to the following tests [insert list
of tests here] and failed".

_Point 4_

This is not a new idea.

Maybe not. But, again, you show no sign of knowing what the
idea is. The idea is that evolution (like behavior) is purposeful:
evolution is the control of (intrinsic) perceptions.

Best

Rick

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--
Richard S. Marken Phone or Fax: 310 474-0313
Life Learning Associates e-mail: rmarken@earthlink.net
http://home.earthlink.net/~rmarken