Geography Reference
In-Depth Information
tective belt is a flexible set of auxiliary hypotheses that are constructed, re-
adjusted, or discarded as directed by the positive heuristic.
Research programs are either progressive or degenerating. Programs
are progressive if each modification leads to novel predictions, which are
confirmed by subsequent research within the confines of the program or by
the chance discovery of new facts. A degenerating program is characterized
by ad hoc modifications or by the persistent failure of its predictions to be
corroborated empirically. Craw and Weston (1984) considered classic dis-
persalismnotaunifiedresearchprogrambutseveralprogramswithdifferent
assumptions (for similar viewpoints, see Savage 1982 and Morrone 2002b).
Additionally, the dispersalist approach is not intended to provide predictions
but instead to produce unique, narrative explanations of the biogeographic
distributions of particular taxa. Craw and Weston (1984) restricted their ana-
lysis to panbiogeography and cladistic biogeography. They suggested that a
fundamental distinction between them—their hard cores—concerns accept-
ing the possibility of random distributional patterns (cladistic biogeography)
and rejecting it (panbiogeography). The aim of cladistic biogeography is to
determine whether such patterns exist, whereas panbiogeography assumes
a priori that patterns are congruent. It follows that cladistic biogeography in-
volves no preference for particular biogeographic processes, whereas pan-
biogeography emphasizes vicariance. After comparing some predictions
formulated by panbiogeographic and cladistic biogeographic analyses, as
Lakatos (1970, 1978) considered for judging competing research programs,
Craw and Weston (1984) concluded that panbiogeography was more suc-
cessful than cladistic biogeography. However, they pointed out that cladistic
biogeography was still in its infancy, whereas panbiogeography was twenty-
five years old, so it was not fair to expect the same progress from both.
Seberg (1986) offered a critique of panbiogeography. After acknow-
ledging the relevance of Croizat's contributions as inspiration for cladistic
biogeography, he analyzed some panbiogeographic concepts. He main-
tained that despite Croizat's dismissal of dispersal and centers of origin,
he used both concepts extensively. Seberg (1986) believed that Croizat's
massive compilation of data was worth mentioning as a relevant contribution
but that his only original contribution was the concept of track. Then, he criti-
cized Craw and Weston's (1984) analysis, suggesting that it has been futile
because Lakatos's (1978) descriptions were not intended to analyze con-
temporary research programs. He found it difficult to view panbiogeography
