[From Tom Bourbon (950831.2224)]
In his reply [From Bruce Abbott (950831.1000 EST)] to my post, "They be
gods" (Tom Bourbon [950831.0041]), one of Bruce Abbott's remarks reminded
me of the classic distinction drawn by William James, between living
systems and inanimate nature. In 1890, James had identified some of the
key features of what we now think of as perceptual control. In one of his
delightful discussions of the subject, he used an example that included the
"behavior" of iron filings in the presence of a magnet -- the kind of
behavior modeled by the physicists whose article I described.
Concerning the physicists, I said:
When the authors talk of how their model and its results apply to living
things, all of their examples of animal behavior are descriptions of
external appearances. The only way their model applies to the behavior of
living things is as an arbitrary way of duplicating some of the outward
appearances of movements by large numbers of actors. The bottom line is
that the particles in their model are like iron filings, not like control
systems, either living or artificial. But the word is out, in Science
News, that physicists can explain cooperative, coordinated movements in
groups of bacteria and social animals and maybe even humans -- watch for
it being cited in other places.
Bruce replied:
Right on the money, Tom. But for me this example does bring up a question
concerning models. If, as the authors say, their model is based on analogy
to the spin-alignment behavior of ferromagnetic atoms in a magnetic field,
then the analogy is to a balance of local forces acting on the "particles"
(e.g., fish).
ยทยทยท
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Back to Tom, in the present.
I agree, if, by your reference to the forces acting on a fish, you mean the
physicists are merely describing _external forces_ that would be analogous
to those acting on a fish (swimming in a current, perhaps?). But if you
mean that the _behavior_ of a fish, exposed to external forces, could be
explained the same way as the behavior of particles in a magnetic field, I
would disagree. The particles would move as they must, given the local
features of the magnetic field. On the other hand, the "behavior"
(movement) of the fish would be completely determined by external forces
alone _only if the fish were dead_. If the fish were alive, it _might_
drift with the current, or it _might_ maintain its position relative to the
river bed in spite of the current, or it _might_ swim and move upstream
against the current. If the fish is alive, its movements are not determined
exclusively by external forces, excluding, of course, forces so great that
they overwhelm the fish as a control system.
And that brings me back to James. For those who have never read him, or
who have forgotten what they read, here is a brief passage on this subject.
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William James (1890). _The Principles of Psychology_. From "Chapter 1.
The Scope of Psychology."
If some iron filings be sprinkled on a table and a magnet brought near
them, they will fly through the air for a certain distance and stick to its
surface. A savage seeing the phenomenon explains it as the result of an
attraction or love between the magnet and the filings. But let a card
cover the poles of the magnet, and the filings will press forever against
its surface, without its ever occurring to them to pass around its sides
and thus come into more direct contact with the object of their love. Blow
some bubbles through a tube into the bottom of a pail of water, they will
rise to the surface and mingle with the air. Their actions may again be
poetically interpreted as due to a longing to recombine with the atmosphere
above the surface. But if you invert a jar full of water over the pail,
they will rise and remain lodged beneath its bottom, shut in from the outer
air, although a slight deflection from their course at the outset, or a
re-descent towards the rim of the jar when they found their upward course
impeded, would easily have set them free.
If now we pass from such actions as these to those of living things, we
notice a striking difference. Romeo wants Juliet as the filings want the
magnet; and if no obstacles intervene he moves toward her by as straight a
line as they. Burt Romeo and Juliet, if a wall be built between them do
not remain idiotically pressing their faces against its opposite sides like
the magnet and the filings with the card. Romeo soon finds a circuitous
way, by scaling the wall or otherwise, of touching Juliet's lips directly.
With the filings the path is fixed; whether it reaches the end depends on
accidents. With the lover it is the end that is fixed, the path may be
modified indefinitely.
Suppose a living frog in the position in which we placed our bubbles of
air, namely, at the bottom of a jar of water. The want of breath will soon
make him also long to rejoin the mother-atmosphere, and he will take the
shortest path to his end by swimming straight upwards. But if a jar full
of water be inverted over him, he will not, like the bubbles, perpetually
press his nose against its unyielding roof, but will relentlessly explore
the neighborhood until by re-descending again he has discovered a path
around its brim to the goal of his desires. Again the fixed end, the
varying means!
Such contrasts between living and inanimate performances end by leading men
to deny that in the physical world final purposes exist at all. Loves and
desires are to-day no longer imputed to particles of iron or of air. No
one supposes now that the end of any activity which they may display is an
ideal purpose presiding over the activity from its outset and soliciting or
drawing it into being by a sort of _vis a fronte_. The end, on the
contrary, is deemed a mere passive result, pushed into being _A tergo_,
having had, so to speak, no voice in its own production. Alter the
pre-existing conditions, and with inorganic material you bring forth each
time a different apparent end. But with intelligent agents, altering the
conditions changes the activity displayed, but ot the end reached; for here
the idea of the yet unrealized end co-operates with the conditions to
determine what the activities shall be.
_The pursuance of future ends and the choice of means for their attainment
are thus the mark and criterion of the presence of mentality_ in a
phenomenon. We all use this test to discriminate between an intelligent
and a mechanical performance. We impute no mentality to sticks and stones,
because they never seem to move for _the sake_ of anything, but always when
pushed, and then indifferently and with no sign of choice. So
unhesitatingly we call them senseless."
The only other person I know who says it that elegantly is Bill Powers.
James had even thought through an equivalent of the test for a controlled
variable.
In 1890, James said, "Loves and desires are to-day no longer imputed to
particles of iron or of air," and, "We impute no mentality to sticks and
stones. . .." Poor James. He didn't live long enough to see examples
of the wonders of modern physics, like those revealed in the article in
Physical Review Letters. 
People who equate the behavior of living things with that of iron filings
demean all living things.
Later,
Tom