[Hans Blom, 951016]
(Bill Powers (951014.0720 MDT))
Nests have several functions, and an adaptive control system
organization will find a way to accomplish those functions quite
independently of how any other system might have accomplished the
same functions. If it happens that two organisms use the same method
to accomplish the same function, the reason may be simply that there
is no other easily-found method that will accomplish that function.
One can't conclude that there is some specific structure inside the
organisms that makes them both use the same method and hence get the
[Hans Blom, how about some help here? If two adaptive control
systems end up controlling the same variables by the same actions,
does this mean that the world-models in the two systems are the
If an adaptive control system had all the basic behavioral capabili-
ties that are required in nest building, AND if it somehow stumbled
-- either by chance or forced by the environment -- upon the combi-
nation of actions that actually resulted in some kind of nest, AND if
it had the possibility to remember this (i.e. connect the actions
with their result into an internal model), AND if the nest building
somehow served some important goal, AND if nest building were, some-
time in the animal's future, again important to reach the same goal,
THEN it might use nest building -- as opposed to some other type of
action -- again to achieve that same goal again.
A lot of conditions (and I' m sure I forgot some), which assumes a
lot of cleverness (perceptive, behavioral and model building capabi-
lities) on the part of the animal. Discovery is not an easy process
by any means. And even then it would explain only the experiential
learning that occurs in ONE animal. Darwin ought to be invoked for a
hereditary mechanism that explains how a SPECIES acquires the trait.
Sections of the world-models of the two species would, indeed, be the
same in that both species have discovered how to reach the same sort
of goal through the same actions. The world-models would probably not
be identical, because other goals are not identical. So one nest
wouldn't be identical to another nest.
"The same" is a fuzzy concept. Two things are never exactly the same.
Sameness is just a label that we apply when we create classes, which
is always a subjective thing. No two rat's nests are "the same", nor
are rat's nest "the same" as robin's nests. Sameness is in the eyes
of the beholder. It's all perception...
In short, at least adaptation in the evolutionary sense, adaptation
in the model-building sense, and adaptation to the environment -- to
usage of whatever materials happen to be available -- are explanatory
categories when we want to "explain" the shape of a particular nest.
I'm not sure whether this helps :-).
P.S.: Don't rely on me for providing you with knowledge. I do,
however, have plenty of opinions.