160 THE STRUCTURE OF EVOLUTIONARY THEORY
preeminence throughout the 3.5 billion years of phylogeny, lest the theory be
reduced to an ornamental device, imposing only a fillip of immediate adaptive
detail upon a grand pageant generated by other causes and forces.
Darwin, who fledged professionally as a geologist (the subject of his first
three scientific books in the 1840's, on coral reefs, volcanic islands, and the
geology of South America), and who regarded Charles Lyell as his intellectual
hero, while embracing his mentor's doctrine of uniformitarianism as the core of his
own philosophy as well, fully understood that his revolution would succeed only if
he could show how natural selection might act as architect for the full panoply of
life's history throughout geological time. The "methodological pole," one of the
two foci of Darwin's revolution (see Section II of this chapter), brilliantly develops
a set of procedures for defending extrapolation in various contexts of limited
evidence.
The link of the first two themes (agency and efficacy) to this third theme of
extended scope or capacity—thus forming in their threefold ensemble a minimally
complete statement of revolution—received succinct expression in Ernst Mayr's
(1963, p. 586) epitome of Darwinism as preached by the Modern Synthesis: "All
evolution is due to the accumulation of small genetic changes, guided by natural
selection [the first two themes of agency and efficacy], and that transpecific
evolution [the third theme of scope, or uniformitarian extension] is nothing but an
extrapolation and magnification of the events that take place within populations
and species."
In this book, my explicit discussion for this third theme of extrapolation
(Chapters 6 and 12) shall be shorter than my treatment of the first theme of agency
(Chapters 3 and 8-9), leading from Darwin's nearly exclusive focus on the
organismal level to the modern revision of hierarchical selection theory, and the
second theme of efficacy (Chapters 4-5 and 10-11) on older and modern critiques
of panadaptationism, with an emphasis on structural principles and constraints. I
allocate my attention in this unequal manner because the first two themes already
include, within themselves, the biological arguments for extrapolation, as
embodied in Darwin's uniformitarian beliefs and practices. For my explicit and
separate treatment of the crucial extrapolationist theme in this work, I therefore
follow a different strategy, if only to avoid redundancy in a book that we all
undoubtedly regard, author and readers alike, as quite long enough already! I will
not rehearse Darwin's biological arguments for extrapolation, but will rather, as a
"place holder" of sorts, concentrate upon the nature of the geological stage that
must welcome Darwin's biological play.
I proceed in this way for a principled reason, and not merely as a
convenience. All major evolutionary theories before Darwin, and nearly all
important versions that followed his enunciation of natural selection as well,
retained fealty to an ancient Western tradition, dating to Plato and other classical
authors, by presenting a fundamentally "internalist" account, based upon intrinsic
and predictable patterns set by the nature of living systems, for development or
"unfolding" through time. (Ironically, such internalist theories follow the literal
meaning of "evolution" (unfolding) far better than the Darwinian system that