[From Bruce Abbott (950527.1410 EST)]
Bill Powers (950526.1605 MDT)
Bruce Abbott (950526.1700 EST) --
My description of how a fly lands on the ceiling is more like the
answer Johnny was looking for--superficial but adequate for the
purpose. I'm not offering an S-R explanation even if it looks that
way on the short form.I guess I see what you mean. It occurs to me that we're using the word
"how" differently, in the question "How does the fly land on the
ceiling?" One meaning is," Tell me all the things that we can see
happening as a fly lands on the ceiling." In the other meaning -- which
is the one I automatically assume -- the question is "What is going on
inside the fly which would account for what we see happening?"
Tell that to Rick Marken. He doesn't get the distinction.
Johnny, after hearing the Marken account of the fly landing on the ceiling:
"No, I mean how does it do it? Does it loop, or roll, or what?"
Bill Powers (950527.0950 MDT)
Illuminating discussion of the difference between the external description
of behavior and the variables used by the organism (and model) to control
perception.
I agree that Nachtigall's description of the fly's landing pattern does not
tell you what variables the fly is controlling when producing that pattern
(although you can make a reasonable guess about some of them based on what
you see the fly doing). What I think has gotten lost in the squabble about
Nachtigall's description (which was intended to answer "how" only in the
sense of what the fly does) is my earlier mention of Nachtigall's
control-system analysis of certain aspects of insect flight (on which you
commented). Rick Marken has forgotten all about this, to the point that he
now asserts that Nachtigall's book is unlikely to have anything to say about
control systems. As your use of the fly-landing description in this post
again focuses on the external description, I though I'd act like a good
control system and "push back" by reminding everyone of Nachtigall's
control-system analysis, offered in the same book.
Regards,
Bruce