330 THE STRUCTURE OF EVOLUTIONARY THEORY
Darwin's Strong but Limited Interest in Structural Constraint
Darwin's Debt to Both Poles of the Dichotomy
Darwin, who understood so well that all organisms must be shaped by their history,
could scarcely build a great structure in the realm of ideas without subjecting his
mental edifice to the same causal influences. Darwin's theory grew in the context
of the formalist-functionalist struggle, and he knew and appreciated the issues and
terminology (see Section I of this chapter).
A cardinal premise of this book holds that Darwin must be ranked in the
functionalist line—for the causal mechanics of his theory grant such clear primacy
to adaptation, however subtly the argument develops. * But any evolutionary
theory, in adding a historical dimension to reshape the simpler world of the
formalist-functionalist dichotomy, would necessarily draw upon both axes of the
old system to build the new, orthogonal dimension of temporal change. In two
senses, formalist thought included great potential to influence Darwin's
evolutionary views.
First, and most obvious in its possibilities (though largely unrealized by
Darwin, I shall argue), classical formalism, with its key concept of
transformational channels within the bounds of archetypal design, followed a logic
intrinsically favorable to a limited form of evolution, while the optimalist
functionalism of Paley, or of Cuvier, rooted the impossibility of transmutation in
the core of their central argument (Cuvier on correlation of parts, for example).
Many of the leading pre-Darwinian formalists supported evolution in this restricted
sense—Geoffroy in France, Meckel in Germany, Owen in England. Yet, although
Darwin could not have been isolated from this influence, I see no strong evidence
that his decision to embrace evolutionism derived from this source (Gruber and
Barrett, 1974; Schweber, 1977; Sulloway, 1982). Moreover, the most prominent
and fully elaborated evolutionary theory available to Darwin (however strongly he
rejected the formulation—see pp. 192-197) resided in the opposite camp of
Lamarck's functionalism. Finally, the content of Darwin's theory, from his earliest
codification in 1838, stood clearly outside formalist thinking—both in replacing
archetypes with flesh and blood ancestors built by adaptation, and in advocating
the functionalism of natural selection itself.
Secondly, Ospovat (1981) presented the important thesis that Darwin's chief
intellectual change within his theory of natural selection between codification
*The subtleties, centering upon two arguments, express great intellectual force, and
constitute the power of natural selection in Darwin's version. First, since selection makes
nothing, and can only choose among variations supplied by other causes, Darwin
developed a theory of variation (copious, small in extent and isotropic—see pp.141-146)
that reduced this evolutionary factor to a status as raw material only, and granted all
power of change to the functional force of natural selection. Second, Darwin brilliantly
used the classical relative frequency arguments of "nooks and crannies" and "sequelae" to
place formalist influence upon evolutionary change at a periphery of unimportance
relative to selection (see pp. 255-256).