Re: intentionally distorting arguments

[Robert A Cohen <bbq@ESU.EDU>]

On Tue, 24 Aug 1999, Ludwik Kowalski wrote:

> I would be happy to be an impartial observer if I followed the debate
> very carefully. Most of us would be probably too busy to serve on a
> jury. Especially now that another school year is about to begin. In my
> opinion phys-L is not an appropriate place for extensive debates among
> experts. On the other hand, watching the debate, even superficially, was
> interesting and informative. But I would delete many messages without
> reading if it were not the summer.
>
> I do not know what else to say. Perhaps somebody who did follow the
> debate very carefully, and who can be objective, will summarize it for
> us and tell us if the accusation is justified.  It is our list and we do
> not spoil it. Somebody must be right and somebody must be wrong but who
> am I to decide?

As an neutral observer in the "upwash vs. downwash", "direct vs.
indirect", etc., arguments, here are my verdicts regarding the recent
discussion (attacks?).  One caveat: I hate to think that anyone is
purposing misleading people, so I admit that biases my viewpoint.

I don't know John Denker personally, but I did initially think that his
posts were more in line with debating tactics than scientific inquiry. Now
that I know more of the history of the debate, I can see why both sides
are so defensive.  Much pride and reputation is at stake.  Still, I don't
think the purpose of discussion is to "kill" your opponent.  I think both
sides were wrong in this respect (two wrongs don't make a right, you
know).

Nonetheless, I don't see the debating tactics as a purposeful technique to
*confuse* the "opponents".  Rather, I think many of the statements that
caused confusion were the result of unclear writing.  With a little time
to think about them, I believe I was able to figure out what the author
"meant" to say and I believe others could do the same if they would just
spend more time to think about the posts before responding.  Thus, my
guess is that much of the disagreement was due more to "knee-jerk"
reactions than a purposeful intention to confuse.  Perhaps participants
should contemplate their response for a day before posting it.  This might
not only decrease the "knee-jerk" reactions that contribute to
misunderstandings but also the amount of e-mail traffic (which was so high
I considered cancelling my subscription).

Personally, I think I see the validity of each point of view.  Below I
list my conclusions.  I'm bracing myself for criticism but would
appreciate some constructive feedback.

1. What is science?

"Make-sense" explanations are useful in science.  Unfortunately, one
cannot objectively determine whether an explanation "makes sense" or not.
Thus, "make-sense" explanations are not science per se.  For example,
creation science may make sense to some people and evolution may make
sense to others.  Interpreting "yom" to mean a literal day in the Bible
may make sense to some people while others think it makes sense to
interpret "yom" as "period of a time".  In some cases, debating which
makes more sense is fruitless.
   Some people think that science must "make sense".  Others think that
science only needs to make accurate predictions.  Whichever the case, just
because something "makes sense" does not make it science.  At the same
time, just because an explanation does not make quantifiable predictions
does not make it useless or misleading.
   I found the Anderson/Eberhardt paper to be useful because its
explanation makes sense to me.  Even though I can't use it to make
quantitative predictions, I can use it to make qualitative predictions
that seem to work in most cases.

   Verdict: both are right.

2. Upwash vs. downwash

If air is accelerated, it can be accelerated because the wing is
exerting a force on it or because the air itself is exerting a pressure
on it (much like normal, everyday wind).
   From what I've learned in these discussions, in many instances the wing
compresses the air below (and toward the front) of the wing.  This
high-pressure region not only pushes on the wing but also pushes on the
surrounding air, leading to upwash.  The upwash, if it occurs below the
wing, might lead to additional lift or it might not.  That is, it isn't
clear to me whether the upwash is "pushed up *with* the wing" or the
upwash "pushes *on* the wing".
   On the one hand, I agree with Denker that the Anderson/Eberhardt
arguments do not address this well.  Just because air is accelerated
upwards does not mean that it is the wing that is exerting the upwards
force on it.  On the other hand, I found Denker's arguments about
air/earth reaction pairs, etc., to be misguided and confusing.  His first
responses on Newton's third law seemed questionable to me, but after some
thought I think I understand what he was trying to say.

   Verdict: both are right.

3. Wing as reaction engine

For the wing/plane to stay up, there must be some air deflected downwards.
This does not mean that the deflected air "causes" the wing/plane to
stay up.  It only means that there must be air deflected downwards.
   On the one hand, I think Denker's attacks on using "reaction engine" in
this way was inappropriate and perhaps a defensive reaction rather than
thought-out responses.  On the other hand, attributing the lift to
downward momentum of air can be misleading.  For example, as the vortex
pair sheds off the wing tips and fall behind the plane, there is downward
motion between the vortex centers.  As far as I can tell, this downward
motion does not contribute to the lift of the plane because it occurs far
away from the plane.  Only the *net* downward motion of the vortex centers
was initially produced at the wing and thus only the net downward motion
of the vortex centers is related (but doesn't cause) the lift.  This is
not stated as such but might be mistakenly concluded.

   Verdict: both are right.

Hey, I'm a moderate.  What can I say?  :^)

In any event, if I am blind or wrong, I would appreciate a response that
has been contemplated for at least a day before being posted.  Thank you.

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| Robert Cohen               Department of Physics       |
|                            East Stroudsburg University |
| bbq@esu.edu                East Stroudsburg, PA  18301 |
| http://www.esu.edu/~bbq/   (570) 422-3428              |
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