[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Science feather strength debate
In your recent posts about the Nudds and Dyke Paper you have called their
conclusions silly. I wholeheartedly agree with you that they should have
presented good figures for proximal rachises along with their conclusions and
that this missing data weakens the paper. But on other points I fear you have
Correct or not, Nudds and Dyke have provided an explicit and empirical
methodology and their conclusions can be supported or falsified on their own
terms. In accomplishing this they have set a high standard for scientific
I would suggest that their method calls for a response in kind, and that you
should recruit a team of eager young biologists and engineers to build
aerodynamic models to test, for example, whether the overlapping feather vanes
of Confuciusornis would strengthen the wing enough to prevent buckling.
You are free to analyze whether the proportionately long arms and short legs of
Confuciusornis correlate in a statistically significant way with flying animals
and do not overlap with non - flying animals.
You are also free to analyze whether there is a statistically significant
correlation between flight abilities and the formation of abundant lacustrine
All of these are scientifically valid responses, but I don't feel that
categorical dismissals are.
You wrote that you were irritated that Nudds and Dyke (and "lots of folks") did
not cite Dinosaurs of the Air. Speaking for myself, I feel that your book could
have been far more persuasive and influential if its methods had been explicit
and if it had proposed methods by which your hypotheses could be falsified.
For example, I could not find the calculations that you used to estimate body
mass for Archaeopteryx in either DA or Predatory Dinosaurs of the World. In the
former you do mention Yalden's calculations, but then you state that his
estimate is too high and you lower it without providing any mathematical reason
for doing so. In your technical comment on Nudds and Dyke you show two
elevation drawings: silhouettes of a pigeon and of Confuciusornis, as your only
evidence that the pigeon weighs more. But a pigeon is a three - dimensional
object, and riven with pneumatic air sacs. If the pigeon was more voluminous
you did not calculate this, and you provide no evidence as to whether the
pigeon is more or less dense than a more basal bird. Then you go on to say that
the lower mass of the Munich Archaeopteryx makes the feathers "several times
stronger" when you must have meant that they have several times less loading.
But my point is that you are less persuasive when you simply write that this is
so than you would be if you provided calculations that can be checked by your
If we hypothesize that Confuciusornis was capable of powered flight, this
hypothesis must be falsifiable in order to be scientifically valid, correct? So
perhaps one day an overwhelming body of evidence will demonstrates that it was
a littoral scavenger that roosted in trees overhanging lakes, and parachuted
down to the shoreline to forage. You and I think that this is highly unlikely,
but that doesn't matter. What matters is that we design experiments rigorously
so that their results will be believable.
Senior Principal Preparator
American Museum of Natural History
(212) 496 3544