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Re: counter-steering, with numbers



This discussion reminds me of an interaction I had twenty years ago
with a colleague from the biological sciences. He was studying archer
fish predation. These lovely creatures, as you may know, garner their
grub by the somewhat distateful practice of shooting it out of the
air with a jet of water expelled from the mouth. My colleague (whom I
was meeting then for the very first time) asked me, quite seriously,
whether I thought it likely that the archerfish understood Snell's
law intuitively and compensated accordingly to sight on his prey from
beneath the surface of the water.

I am a somewhat obtuse fellow as most of you know, so I answered his
sincere question by saying "Why don't you ask the archerfish?" The
question was not rhetorical, however, and there is a point. Finally
he said "Why, of course the archerfish can't tell me. He's not human."

To this I replied "Do you suppose that if you asked Willie mays how
he catches balls in center field whether he takes air resistance into
account when determining the point in center field to run to that he
would be able to tell you?" The answer is that he likely would not do
so, of course, and that is my point. In pursuing a livelihood only
physicists are introspective at the level of fundamental principles.
All others learn to do whatever it is they do by trial and error.
Their brains are wired by reinforcement of success or else they
starve to death.

Riding a bicycle is like that. The system is just too complicated to
be explained simply. Physicists are simple; they solve problems only
if the problems are of comparable simplicity. I predict that Willie
Mays, equipped with the best available speed sensors (radar gun?) and
the fastest computer imaginable, together with the best model code
for projectile flight in a viscous medium (a hydro code of extreme
complexity), would lose his job with the Giants were he to rely on
the predictions made from first principles. He did better than that!
When a theory is formulated that comes up with, say, the optimum head
tube angle for a bicycle (known to be ca. 71-72 degrees) then I will
know progress is being made.

Incidentally, my colleague in biological sciences turned out to be
quite a reasonable fellow. We've even coauthored a chapter in a book.

Leigh