The Modern Synthesis as a Limited Consensus 543
More strongly selectionist models would be favored by biologists who
modelled themselves after physicists at the same time they pointed the way
to the "improvement" of humanity and painted a progressive and optimistic
picture of the world... Evolutionary models favoring random genetic drift,
which enforced a stochastic view of evolution—and culture—would not be
favored in a post-war frame of mind seeking to "improve" the world. So
powerful would be the need for a progressive and selectionist framework in
the 1940's that even Dobzhansky and Wright were to adopt more strongly
selectionist models. *Some complex mixture of empirical and sociological themes may explain the
adaptationist hardening of the synthesis, but we must not neglect the additional
impetus of a cultural analog to drift and founder effects in small populations. The
community of evolutionary biologists is sufficiently small, and sufficiently
stratified—a few lead and many follow, as in most human activities—that we need
not necessarily invoke some deep and general scientific or societal trend to explain
a change in opinion by a substantial community of evolutionists in different
nations. A reassessment by a few key people, bound in close contact and mutual
influence, might trigger a general response. The three leading exponents of
hardening in America—Dobzhansky, Simpson, and Mayr—worked together as
colleagues in a "New York Mafia" centered at Columbia University and the
American Museum of Natural History. Add another seemingly eternal principle of
human affairs—that founders tend to be brilliant and subtle, and to keep all major
difficulties constantly in mind, while epigones generally promulgate the faith and
disregard, or never learn, the problems, exceptions, and nuances—and we may
then wish to view the adaptationist hardening as ultimately inadaptive for the
broadest goal of understanding evolution aright. Bandwagons might well be
construed as cultural analogs of internalist drives in nonfunctional orthogenesis.
Theories can grow tired. Theories can also harden and lose their bearings when
complacency occupies the driver's seat.
Hardening on the Other Two Legs of the Darwinian Tripod
To illustrate the hardening of the Modern Synthesis, I have documented its most
significant ontogenetic trend in extenso—increasingly exclusive emphasis on
adaptation as the sign of natural selection's pervasive power. But if we epitomize
the Synthesis as Darwinism reclothed in Mendelian understanding,
*I am not generally drawn to sociological proposals in this mode, and I reacted
negatively at first to Smocovitis's suggestion. But I have since read widely in the just
post-World War II literature, and I only now understand the fervor and hope of "never
again," following all the devastation, and the heartrending impact (and inspired shame) as
knowledge of the Holocaust surfaced. I was too young, when the war ended, to
experience viscerally both this horror and hope, but I do grasp the character of this
unusual time with a pervasive theme and agenda—and I accept the idea that
humanistically inclined scientists must have hoped fervently that their own field might
contribute to the reconstruction.