1200 THE STRUCTURE OF EVOLUTIONARY THEORY
of a grid, then the transformed grid itself would become a picture of the lines of
forces responsible for the evolutionary deformation. Thus, D'Arcy Thompson valued
the lines of the transformed grids above the altered organisms themselves, for he
hoped that his pictures of simple and coordinated transformation would revivify his
theory in a more limited domain. The lines of transformation would map the forces
that converted the initial form into its descendants or relatives—and by D'Arcy
Thompson's theory of direct imposition, those lines would then identify the geometric
operation of the actual forces that caused the evolutionary changes by direct
imposition. He would not win hipponess (or full happiness) for his theory, but he
might encompass the set of realized variations upon hipponess. Put another way,
perhaps D'Arcy Thompson could "have it all" for the simple forms of some unicells;
but he would have to settle for the variations (leaving the fundamental configurations
to history and heredity) when he treated the complexities of vertebrate organization.
Sweet indeed are the uses of adversity, as D'Arcy Thompson put his best
possible spin upon a positive ending to a most unwelcome admission (p. 723):
But in a very large part of morphology, our essential task lies in the
comparison of related forms rather than in the precise definition of each; and
the deformation of a complicated figure may be a phenomenon easy of
comprehension, though the figure itself have to be left unanalysed and
undefined. This process of comparison, of recognising in one form a definite
permutation or deformation of another, apart altogether from a precise and
adequate understanding of the original "type" or standard of comparison, lies
within the immediate province of mathematics, and finds its solution in the
elementary use of a certain method of the mathematician. This method is the
Method of Co-ordinates, on which is based the Theory of Transformations.Odd Man In (D'Arcy Thompson's structuralist critique of
Darwinism) and Odd Man Out (his disparagement of historicism)
I premised this discussion by arguing that D'Arcy Thompson's showy singularity in
both style and substance—the quirks and anachronisms that seem to place him "out
of time"—must not blind us to the fact that these uniquenesses overlie a rather
standard early 20th century structuralist critique of Darwinian functionalism. D'Arcy
Thompson's residence within his own time therefore becomes as informative as his
idiosyncrasies.
In particular, I have emphasized, throughout this book, the logical and almost
ineluctable linkage in structuralist thought between defenses of internally channeled
directionality and saltationist mechanics (as particularly exemplified in the definitive
model of Galton's Polyhedron—see pp. 342-351). I have also stressed the equally
tight relationship of these views to a critique of adaptations—not of their preeminent
existence (which D'Arcy Thompson embraces and celebrates), but of their necessary
construction "for" utility by