Re: The Cambrian Explosion

John P Turnbull (jpt@ccfdev.eeg.ccf.org)
Thu, 7 Dec 95 13:55:36 EST

Jim Foley wrote:
>
> >>>>> On Wed, 6 Dec 95 12:37:24 EST, John P Turnbull
> >>>>> <jpt@ccfdev.eeg.ccf.org> said:
>
> >> Gould does not describe people like Walcott as deceitful. But
> >> he forcefully makes the case that our preconceptions can have
> >> a powerful influence on coloring our perception of reality.
> >> And when the facts didn't fit they simply closed their minds.
> >> They refused to accept the now established fact that the testimony
> >> of the fossils told a very different history of life then the
> >> history they expected. I admire honest scholars like Stephen
> >> Jay Gould who have attempted to set the record straight. Perhaps
> >> now we will all know that the perception we all learned about the
> >> fossil record derived from Darwin's expectations were false.
>
> Much as I like his writing, the general concensus now seems to be that
> Gould considerably oversold his case. A number of the "wierdo fossils"
> have since been fitted into some of the existing phyla, and one of them,
> Wiwaxia, is now in the same place Walcott put it in in 1911.
>
> So the truth lies somewhere between the Walcott and Gould viewpoints,
> and may, for all I know, end up closer to the Walcott end of the
> spectrum. I have a couple of posts saved which go into more detail,
> email me if you want them.
>

This misses the main theme of the post. Stephen Jay Gould
discusses the classification of specific Burgess Shale fossils
within the context of a larger issue he wishes to address:
The role of subjective interpretation in the scientific method.
Few today would dispute Gould on his example of earlier Darwinist
iconographs demonstrating the linear progression leading upward
to modern man through the conventional racist sequence was not
only bad science but was constructed to promote a specific (and
harmful) social agenda. His example of Osborn's comparison of
brain sizes depicted, in order, chimpanzee, Homo Erectus, Piltdown,
Neanderthal, and Modern Man is particularly revealing. Gould
does not criticize the scientists for having been taken in by
the Piltdown hoax, but the point he made is that the illustration
drew the Piltdown brain size intermediate to chimp and modern man
because Osborn's colleagues were so convinced that that's the
way the data ought to look that they reconstructed it that way,
EVEN THOUGH THE PILTDOWN SKULL WAS FULLY MODERN. Osborn's
colleagues also drew Neanderthal brains as smaller even though
actual measurements demonstrate that on average, they are as
large or larger than contemporary man's. Did subjective expectations
influence earlier investigations? Unquestionably, yes.

To what extent is this relevant to the classification of Burgess
Shale fossils? It could very well be that taxonomists, troubled
by the sudden abrupt appearance of fossils representing so many
phyla will have reason to want to shoehorn as many of the odd-ball
fossils into existing phyla to reduce the impact of the finds within
a Darwinist paradigm. But whatever the final result, it is
irrelevant to the main theme of my post. Even if all Cambrian
fossils are ultimately classified (by objective criteria, we hope)
in known phyla (and scientists will have "only" to explain the sudden
appearance of all but one modern phyla) this does not alter the
message of the fossil record: Disparity Precedes Diversity.

God Bless,

-jpt

--
John P. Turnbull (jpt@ccfdev.eeg.ccf.org)Cleveland Clinic FoundationDept. of Neurology, Section of Neurological ComputingM52-119500 Euclid Ave.Cleveland Ohio  44195Telephone (216) 444-8041;  FAX  (216) 444-9401