FW: Islands, Science and Creationism

John R. Grehan jrg13 at PSU.EDU
Tue Apr 16 11:50:53 CDT 2002

Let's say that
>there is solid biological evidence that certain members of an island biota
>are unlikely to have dispersed there;

Although dispersability or lack thereof is not part of the panbiogeographic

>that in fact they all show a similar
>*pattern* of occurrence, independent of their common lack of vagility. But
>geologists say that the islands were never connected to the mainland.
>A subservient biogeography would discard the biological evidence. After
>all, the geologists must know what they are doing. They certainly knew what
>they were doing when they claimed that the continents were immovable, and
>we built an entire biogeography around that, so why should we switch now?

Exactly. I have seen statements in the biogeographic and geological
literature saying something to the effect that we 'know better' now about
geology (i.e. past mistakes represent a naive state that we have now

>But a biogeography that is a science in its own right will take the
>evidence to its logical conclusion. So what if that contradicts geology?
>One or the other is likely to be wrong, and we deal with that by *looking
>for additional evidence*.

I agree in principle. The nature of the additional 'evidence' is where
things can become tricky. What constitutes evidence is not always
straightforward and there are different kinds. One may take different
evidence from biogeography or geology for their respective positions
without actually refuting one or the other - the contradiction will still
remain. In panbiogeography one of the most important achievements of the
method (in my opinion of course) is the success of the method in predicting
new geological discoveries. In this context corroboration may constitute
evidence, at least of the efficacy of the method in generating new
knowledge even if one may still reject the historical model that generated
that knowledge (for example the composite tectonic structure of the
Americas was predicted from a historical model of Pacific and Atlantic
origins, yet the Pacific origin is regarded by some (e.g. Cox) as an
'illusion' because if contradicts accepted (by the critics) geological

>Just as organisms in their beings carry traces of their entire evolutionary
>history, in their locations they carry traces of their entire geographic
>history. And just as preconceptions of homology have led us astray, so can
>preconceptions of geographic history give us the wrong answers.


John Grehan

Frost Entomological Museum
Pennsylvania State University
Department of Entomology
501 ASI Building
University Park, PA 16802. USA.

Phone: (814) 863-2865
Fax: (814) 865-3048

Frost Museum

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