The Fruitful Facets of Galton's Polyhedron 399
Bateson recognized that both Lamarckism and Darwinism, as functionalist
mechanisms, posited a flow of information from environment to organism as a
basis of adaptive transformation. How then could a continuous environment yield
our world of thinly populated morphospace, with vast gaps between realized
designs? "According to both theories [Lamarckism and Darwinism], specific
diversity of form is consequent upon diversity of environment, and diversity of
environment is thus the ultimate measure of diversity of specific form. Here then
we meet the difficulty that diverse environments often shade into each other
insensibly and form a continuous series, whereas the specific forms of life which
are subject to them on the whole form a discontinuous series. The immense
significance of this difficulty will be made more apparent in the course of this
work" (1894, p. 5).
For Bateson, a general solution could be derived from logical implications of
the argument, prior to any search for causes: nature's discontinuity must arise from
the internal workings of organisms: * "Such discontinuity is not in the
environment; may it not, then be in the living thing itself?" (1894, p. 17).
Bateson, as a young Turk inspired by ideals of German mechanism and American
experimentalism, but working in a more traditional world of descriptive natural
history, knew what he didn't like about the inferential procedures of most
Darwinians in his generation: the conjoined tactic of speculation based on
embryology for phylogenetic reconstruction, and guesswork about utility for
inferences about adaptation by natural selection. Bateson lists the two pitfalls of
such sterile work: "The first of these is the embryo-logical method, and the second
may be spoken of as the study of adaptation. The pursuit of these two methods was
the direct outcome of Darwin's work" (1894, p. 7).
Bateson longed to apply the mechanistic style of experimental science to the
causes of evolution. If guesswork about externalities had served the field so poorly,
why not look to the intrinsic characters of organisms, features that might be
resolved by manipulation and by understanding the mechanics of heredity.
Variation itself must be taken as a primary phenomenon. Why, at least as an initial
strategy, look beyond this palpable and measurable property of populations?
Perhaps the causes of evolutionary change lie in variation itself and not in a
superimposed external sorting, as the more complex Darwinian mechanism
proposed: "Variation, in fact, is evolution. The readiest way, then of solving the
problem of evolution is to study the facts of variation" (1894, p. 6).
*Central though this question may be to Bateson's inquiry (and sympathetic as I am
to his book), I confess that I have never understood why Bateson regards this point as so
telling and decisive. I think that Darwin presented a simple and perfectly satisfactory
solution to this dilemma (which he clearly recognized and discussed at length in early
chapters of the Origin)—namely, that forms once filling the gaps between modern
discontinuities have now become extinct. (Most intermediates, after all, are not
contemporary creatures, but graded series on two lineages of ancestors running back to a
common branching point, often deep in the geological distance.)