The Fruitful Facets of Galton's Polyhedron 443
Darwinism did not rank as a dominant philosophy at the time, and issues of heart
hold such evident prominence for de Vries.) The Mutation Theory, with its
explicitly saltational and nonadaptational origin of species, must be read as a
confutation of Darwinism on the central question (the title of Darwin's book, after
all) of "The Origin of Species." And yet, by an interesting argument (developed in
the next section), de Vries did provide a genuine and ample field for Darwinian
logic in another realm, even while he tried to extirpate natural selection without
compromise on its own original turf.
THE LOGIC OF DARWINISM AND ITS DIFFERENT PLACE IN DE VRIES' SYSTEM. I
have documented the psychological vacillation in de Vries's assessment of Darwin,
but a stark contrast must be drawn between this frustrating emotional
indefiniteness and de Vries' clear and subtle understanding of selectionist logic. I
think that only two other early evolutionists— Weismann and Darwin himself—
ever grasped so fully, both in basic logic and expanding implications, the rich
meanings of selectionism. De Vries' personal dilemma lay in his unwillingness to
tar his personal hero with the brush of selectionist errors (in his judgment), not in
any softness or vacillation in understanding selection itself. Thus, he tried to
distance Darwin from Darwin's own beliefs, grasping at straws (often of de Vries'
own construction) in tortuous exegetical efforts to remake Darwin as a closet
saltationist.
One can hardly deny that de Vries' Mutation Theory represents, in principle,
about as anti-Darwinian a mechanism as anyone could construct at the crucial level
of Darwin's own concerns (and chosen book title)—the origin of species. Neither
selection nor adaptation can play a creative role in evolutionary change if new
species arise in single, fortuitous leaps.
Yet de Vries insisted that his theory followed Darwinian principles at the
larger scale of full unrolling of life's history—and here he presented a sound and
fascinating argument that his contemporaries never understood (in their failure to
grasp the generality of selectionist logic) and that later history therefore, and
unfortunately, forgot. I argued in Chapter 2 that the operation of a selectionist
mechanism makes three crucial demands upon the nature of internal "raw
material": that variation be copious, small in scope (relative to the unit of
incremental change at the scale under consideration), and undirected (isotropic). At
the level of speciation, de Vries' Mutation Theory becomes decidedly anti-
Darwinian by failing the second test—for single mutations generate new species in
one step, and no creative role can be assigned to selection or adaptation at all.
But suppose that we "promote" our gaze and consider evolutionary trends
through geological time as the relevant scale of change. Then a species-forming
mutational step might be considered sufficiently small (relative to the full trend) to
fit into Darwinian logic—though not into Darwin's own theory, which explicitly
requires, as its central tenet, that a process of organismal selection must govern the
origin of species.
But if we can regard speciational steps as small increments in macroevolution,
then the applicability of Darwinian logic to trends would depend