anthropology, prediction, evolution, etc.

John McCreery (JLM@TWICS.COM)
Wed, 13 Sep 1995 08:01:12 +0900

It's been fun sitting back for a few days to see what other people would have tosay about what are to me several interesecting threads on prediciton, evolutionary theory, the relevance of "laws" to anthropology. Alvin Dark has said that
prediction is impossible. Brad Hume has invoked quantum mechanics to support
the idea that everything is probabilistic; he seems to imply a conclusion similar to Dark's. Bob Graber holds out mightily for the possibility of lawlike
generalizations. Here, too, we find Mike Carson and what I perceive as a position close to my own in Mike Tomaso. Then I read Ruby Rohrlich's contribution,
which I quote at length below.


Timothy Ferisin his rev iew of Murray Gell-Mann's *THE QUARK AND THE
JAGUAR: Adventures in the Simple and Complex* concludes thusly: " For
many readers, the best thing aout "TheQuark and the Jaguar* is not so
much its discussion of technical issues as the way it conveys something
of the excitement and majesty of the quantitative, scientific way of
looking at things. Certainly Gell-Mann's passion for living things helps
to explain the bare-bones equations that scare so many people away from
science. In a characteristic passage, Gell-Mann notes that the
ornithologist Charles Munn, studying feeding flocks in a tropical forest
in Peru, found that they typically are accompanied by 'sentinel' birds
that call out to warn of approaching raptors. Sometimes the sentinels
make false calls: "The fake alarm often permitted the sentinel to grab a
succulent morsel that another member of the flock might otherwise have eaten.
"Careful observation," Gell-Mann writes, "revealed that the sentinels were
practicing deception about l5% of the time and often profiting by it. . .
. Presumably, if the percentage were much higher, the signals would not
be accepted by the rest of the flock and it if were much lower, the
opportunity for the sentinal to obtain extra food by lying would be
partially or wholly wasted. "I am intrigued by the challenge of deriving
b y some kind of mathematical reason the figure of about l5%," he
continues. "In a plausible model, might it come out one divided by two
pi?" When I asked that question of Charles Bennett, the UCLA ecologist,
he was reminded of something his father had told him about Royal
Canadian Air Force units based in England during World War II. They
found it useful when sending out a fighter and a bomber together, to
attempt occasionally to deceive the Luftwaffe by positioning the fighter
below the bomber rather than above. After a good deal of trial and
error, they ended up following that practice at random one time in seven
-- in other words, ab out l5% of the time. I don't know whether
Gell-Mann the birdwatcher sees tongues in trees, but there is something
more than a little charming in the notion that he sees birds as
mathematicians." I also found the notion more than a little charming.
Ruby Rohrlich.


I am struck, as I think Ruby meant us to be struck, by the difference between
Gell-Man's approach to things and the philosopical muddling to which all of us
here seem prone. We talk abstractly about prediction, evolution, deception, etc.Gell-Man offers an observation. Sentinel birds deceive other birds about 15%
of the time and says "I am intriqued by the chllenge of deriving some kind
of mathematical reason for the figure of about 15%." He is focused, specific,
quantified, yet ready to make generalizing leaps like the one that links the
birds to the Canadian Airforce Units in World War II (Whoops I take that back,
wasn't Gell-Man, that was the reviewer. Please pardon the slip but hold the
point.) That's science. Dare we assert that what we're about is more than mere

Cheers, dear friends.

John McCreery