paleonet Gaps, damned evidence, and statistics.

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James Clark's webpage on two of the most significant "gaps" in palaeontology
( http://www.gwu.edu/~clade/faculty/clark/theropodgaps.html ) is a fine
demonstration of the scientific technique commonly used in this discipline.
I admire the fortitude he and the rest of his team must have shown in
central Asia, but the interpretation of their finds is a different matter.
Think what you will of me for questioning those without whom we would have
no material to discuss, but if the whole business is about understanding the
past, there's no point going to all that trouble in the first place if
you're always going to draw the wrong conclusions.

Proper scientists posit competing theories and see which explains the most.
Simple though this recipe may be, people fall over themselves to mess it up.
I invite you to bear in mind the following two strategic errors as we check
out one or two details of misinterpretation of pseudo-gaps:

1:  The assumption of the minimum conceivable reversals, branding any theory
envisaging more than the minumum as a violation of scientific principles
since in your school it does act as a basic scientific principle.

2:  Lurking in the wings, the ever-ready willingness to respond by
"attacking a false hybrid" - that is, extracting an element of an opposing
argument, and showing how it clashes when slotted into your argument, all
the time ignoring the obligation to test the opposing theory IN ITS ENTIRETY
against undisputed observations.

Instead of posing two or more theories and seeing which matches the evidence
best, Clark follows the usual practice of introducing aspects of his own
theory as accepted truths, ignoring alternative theories:

"Humans have a fossil record extending back over 5 million years (perhaps
over 6), whereas chimpanzees - our closest relatives - have no recorded
fossils older than a few thousands of years ...

They do Jim, but not as you know them.  There is no acknowledgement that a
lack of chimp and gorilla fossils is merely a part of his theory; it is
simply stated as fact.  The theory that says such fossils DO exist is barely
if at all mentioned, as of course is it never mentioned in "Nature" or "New
Scientist" since Gee and Hecht are able to censor it.  You will however get
a better insight into palaeoanthropology through reading Gribbin & Cherfas'
"The First Chimpanzee".

"Because the five+ million year old fossil relatives of humans share with us
unique features not found in chimpanzees, they already were on the
evolutionary lineage leading towards us and away from our common ancestor
with chimpanzees."

"The fossil humans are presumed not to have been the ancestors of
chimpanzees since this would require "de-evolving" the human features they
had already evolved, something that is possible but contrary to the evidence
at hand."

Possible indeed, but it is a crude lie to claim it is contrary to the
evidence at hand.  Remember, evidence is those observations more consistent
with one theory than another.  Consider the two theories:

First, that chimps split from the human line before becoming bipedal;
Second, chimps split from the human line after becoming bipedal.

Observations explained by the second but not the first, include:

* The molecular evidence points to a split no earlier than 4.0 mya.

* Chimps and gorillas walk on their hands differently from the standard
basal primate method.

* Many australopithecine fossils show a trend over time from extreme
bipedality to bipedality with quadrupedal compromisees.

* No quadrupedal chimp/gorilla fossils have been found between 5-1 mya while
many bipedal examples "on the human line" have been found.

* Bipedal australopithecines in gracile small-molared and robust
large-molared forms "vanish suddenly" without issue or explanation, and then
chimps and gorillas with large and small molars respectively suddenly
appear.

"Applying this logic to the fossil record of coelurosaurians..."

I shiver when I hear a palaeontologist use the word logic...

"... [...] studies of their relationships indicate [...] that birds are
nested well within the coelurosaurians, implying gaps in most of the other
coelurosaurian groups."

By which is meant he has a theory that this is so.  To have one gap might be
considered a misfortune; to have gaps all over makes for a very ragged
theory.

"The closest relative of the bird lineage is probably..."

The word "probably" used in this way marks up people who know next to
nothing of the essential lessons of "The Logic of Scientific Discovery" and
"Conjectures and Refutations".  It is precisely those new theories that make
predictions considered improbable to old theories that are nonetheless borne
out, that are the most valuable.

"...the dromaeosaurs (although there is not yet a consensus among
paleontologists on this), so a representative of this group must also have
been present in the Late Jurassic."

So that's telling you then - the missing droms, ovis, ostrich mimics etc
prior to or even co-eval with Archaeopteryx, is a definite unexplained gap.
Nowhere is the idea of Archaeopteryx being ancestral to those Cretaceous
coelurosaurians even mentioned because although it explains great swathes of
"paradoxes", it violates the essential scientific priciple of not being
favoured by those employed in the field.

(Nice Cardinal finch; just fancy a flying creature having a sagital crest
like that ;-)

How often has Paul-inspired artwork been used to illustrate competing
theories without even mentioning his?  Shall we count the times?  Let's make
this No. 1 in our scrapbook.)

If you really do claim to be scientists, why not follow the use of
hypotheses not just outlined by Popper, but followed by statisticians for
the last hundred years?  They, you may remember, calculate the probability
of seeing the evidence we do, given certain hypotheses.  If that probability
is low enough - as it is for these two gaps being just bad luck - the theory
should be rejected.  I've had a stab at this here:
http://www.geocities.com/strangetruther/ManiStats.html [now extensively
tidied up!]; you should bear in mind the evidence for dromaeosaurs etc NOT
living prior to Archaeopteryx is on a par with dinosaurs not living after
the Cretaceous.  (The link to the webpage in my site I mentioned on paleonet
a few weeks ago detailing a more plausible family tree of dinobirds is now
correct: http://www.geocities.com/strangetruther/jj2ftree.html .)

It's very difficult to try, or appear, to pursue science while avoiding
contradicting the views of any influential people within your field.  I
couldn't do it and I salute your heroic efforts to do so, but it would
benefit science, and be a lot easier, if you simply followed the simple
protocols concerning scientific practice and evidence I have mentioned in
this posting.

JJ