556 THE STRUCTURE OF EVOLUTIONARY THEORY
This argument seems clear enough in logic (its validity, or relative frequency,
in the world of real populations raises a different issue that can only be resolved
empirically). Why was Wright's theory misunderstood or, even worse, simply
ignored? I suggest the following (and unfortunate) primary reason: How could
Wright's argument be grasped by an intellectual community now committed to the
exclusivity of organismic selection? The conceptual tools no longer exist under
such a stricture: adaptation arises by "struggle" for reproductive success among
genes or organisms; drift causes a population to depart from a place attained by
such struggle. How then could drift possibly act as a helpmate to adaptation? To
grasp Wright's view, one must allow for a higher level of interdemic sorting, and
one must understand the logic of hierarchical models, with sorting operating at
several nested levels.
The intellectual space for viewing drift as an aid to interdemic selection
doesn't exist in a context of exclusive commitment to selection at genie or
organismic levels. Wright's idea then gets demoted to a status even lower than
"merely wrong" in such a world; "shifting balance," in Wright's own sense,
becomes inconceivable, and therefore intellectually inaccessible. Erroneous ideas
can at least be expressed and made available to others with potentially different
opinions. But the definitions of orthodoxy simply erased Wright's multiple-level
theory—in much the same way that evolutionary stasis could not be recognized as
interesting, or even grasped as a phenomenon at all, within a community
committed to gradualism. When we think an idea through, and then reject the
notion, we have at least made an intellectual decision (perhaps wrong, perhaps
overly rigid). But when we maintain an unarticulated and unexamined
commitment, and then use such a premise, albeit unconsciously, to render
interesting ideas inconceivable, then we have fallen under the spell of dogma.
Sewall Wright—unlike Schubert, Wegener and a host of historical figures
deemed tragic—lived long enough to witness his vindication (and to participate
mightily in his renewed respect by writing a four-volume mathematical treatise,
largely during his eighties—see Wright, 1978). But his period of unjustified eclipse
should warn us all about the dangers of bandwagons and unexamined
commitments.
EXTRAPOLATION INTO GEOLOGICAL TIMEA good flavor of the confidence, even the dogmatism, of the hardened synthesis, as
presented at the Darwinian centennial celebrations of 1959 (see pp. 569-576),
shines forth in Mayr's introductory proclamation from his 1963 book. Mayr
pronounces the "complete unanimity" of competent professional opinion, the
"colossal ignorance" of the "few dissenters," and the consequent "waste of time"
involved in any refutation of the intellectual stragglers:
When we reread the volumes published in 1909, on the occasion of the 50th
anniversary of the Origin of Species, we realize how little agreement