Haldane and the Emergence of Modern Evolutionary Theory 79to describe this replacement in his chapter... on the unity of the
genotype.... This chapter contains a large number of enthusiastic
statements about the biological advantages of large populations which,
in my opinion, are unproved and not very probable. The plain fact is
that small human isolates, whether derived from one ‘race’, like the
Hutterites, or two, like the Pitcairn Islanders, can be quite successful.
I have no doubt that some of the statements in Mayr’s chapter... are
true. If so, they can be proved by the methods of beanbag genetics,
though the needed mathematics will be exceedingly stiff. Fisher and
Wright have both gone further than Mayr believes toward proving some
of them. The genetic structure of a species depends largely on local
selective intensities, on the one hand, and migration between different
areas, on the other.... The ‘success’ of a species can be judged both
from its present geographical distribution and numerical frequency and
from its assumed capacity for surviving environmental changes and for
further evolution. I do not think that in any species we have enough
knowledge to say whether it would be benefited by more or less ‘co-
hesion’ or gene flow from one area to another. We certainly have not
such knowledge for our own species.... Sewall Wright has been the
main mathematical worker in this field, and I do not think Mayr has
followed his arguments. (pp. 48–49)His conclusion was: “In my opinion, beanbag genetics, so far from being obso-
lete, has hardly begun its triumphant career” (p. 49).
Among most evolutionary biologists, Haldane’s defense settled the question for
the next generation. With one notable exception, that of Ewens [1993], Mayr has
received little support from scientists. Meanwhile, he opened a second front, now
rebottling himself as a historian and philosopher of biology. From a sociological
point of view, the transformation was successful but that issue is beyond the scope
of this paper. In the late 1970s, Mayr, with Provine’s help, organized a conference
on the history of the evolutionary synthesis. It brought together historians and
all the living scientists whom Mayr considered to have been important in the
synthesis. In spite of Provine’s involvement — and Provine was already working
on Wright’s biography — Wright was not invited.^37 At that conference, Lewontin
[1980] delivered an uncompromising defense of mathematical population genetics,
of the work of Fisher, Wright, and Kimura, but ignored Haldane. Carson [1990]
underscored the significance of Haldane’sCauses of Evolution, as noted before.
Otherwise it was entirely Mayr’s event. The naturalist account metamorphosed
into its mature form with the synthesis allegedly occurring between 1936 and 1947.
Mayr conveniently ignored the fact that in 1955 he had explicitly admitted that
the naturalists had not yet successfully incorporated the necessary genetics into
their framework. By now, he claimed that they had — with some help from others
(but not mathematical population geneticists) — achieved the synthesis by 1947.
(^37) Will Provine (personal communication).