Cladists on reciprocal illumination

[Tom DiBenedetto]

John Grehan wrote: quoting Platnick and Nelson (1988)

> Although Craw is certainly correct that incongruence with a recognized >biogeographic pattern can suggest that a systematic hypothesis is incorrect [a >crucial admission that seems at variance with their position],...

Why is this seen as "crucial" and why is it seen as being at variance with their
position? Biogeographic incongruence can give reason to doubt the phylogeny. So
can many other things. But the phylogeny is not thereby rejected or refuted. One is
simply put on notice that either the biogeographic pattern or the phylogeny, or both
are wrong - and that both should be looked at more carefully. It does not argue for
modifying ones phylogenetic conclusion to reflect the biogeographic information.

Tom diBenedetto


Tom DiBenedetto