Trading, Evolving

[From Rick Marken (970729.1500 PCT)]

Bruce Abbott (970729.1025 EST)--

It is apparent to this lone indian that the settlers are in no
mood for trade.

We keep making the mistake of assuming that you're a settler too.

As for trading, the terms of the deal are simple: you help your
tribe become "testers for controlled variables" and we let you
call us by our first names;-)

Bruce Abbott (970729.1200 EST) to Bill Powers (970729.0606 MDT) --

Sorry to burst your bubble, but you haven't done your homework.

I think you must have missed the central point of Bill's
(970729.0606 MDT) description of the control theory model
of evolution. The central point was that variations in
phenotypic characteritics of organisms are the _outputs_ of
a control process that actively varies these outputs (over
generations) as the means of keeping intrinsic variables (for
each individual member of a species) in their reference state.
The outputs themselves don't tell us much about evolution;
rather, the inputs affected by these outputs (the controlled
intrinsic variables) tell us what evolution is about. Indeed,
according to the control theory model, looking only at the outputs
(phenotypes) of evolution can be quite misleading (just as looking
only at the outputs of behavior can be quite misleading). For one
thing, one output (say, surface area of a wing) might contribute
to the control of several intrinsic variables; similarly, one
intrinsic variable (say, core temperature) may be influenced by
many output variables.

The control theory view of evolution is as different from
the natural selection view as the control theory view of
learning is from the reinforcement view. In the control theory
view, phenotypes are actively varied over generations as the
means of controlling intrinsic variables; in the natural selection
view, phenotypes vary passively (as the result of random mutation);
if a new phenotype happens to increase the chance of its posessor's
survival the genotype for that phenotype tends to get passed on to
subsequent generations.

As Bill notes, both models can "work" (produce the basic phenomeon
of evolution). But the control model works much more efficiently,
and this efficiency might be necessary to account for adaptation
to "sudden" environmental changes that occur over periods of
thousands rather than millions of years. The control model also
suggests that there are variables (intrinsic variables) that remain
constant across generations of organisms despite generational
changes in phenotypic variables. This possibility has never been
tested by biologists who are unaware of the possibly that evolution
is the process of controlling intrinsic variables. Again, this is
the same situation that exists in psychology, where psychologists
continue to study the variables that influence behavior while
ignoring the (controlled) variables that are _influenced by_
behavior. As Bill says:

It's the same old story: if you don't know that controlled
variables exist, you won't look for them.




Richard S. Marken Phone or Fax: 310 474-0313
Life Learning Associates e-mail: