684 THE STRUCTURE OF EVOLUTIONARY THEORY
reasons, must stand as prototypes for our parochial concept of how a proper
Darwinian unit must function in natural selection. If we could ever truly grasp the
gene's world, with full sympathy and appreciation for relative frequencies, hard-
line selectionism would yield to a fascinating enlargement that would actually
strengthen selectionist theory by synergism with other (non-contradictory)
forces—so this subject should therefore not intimidate strict Darwinians. For the
most part, however, the necessary acknowledgment of different gene-level
processes has unfolded within the traditional perspective of organismic selection—
with three basic categories of interpretation as "good" for organisms, and
acceptable on this basis; "bad" for organisms, and a destabilizing danger that must
be conquered; or irrelevant to organisms and therefore unimportant. * The
implications for a hierarchical reconstruction of evolutionary theory have therefore
been missed or downplayed. Consider the two major themes of recent literature:
MOTOO KIMURA AND THE ‘NEUTRAL THEORY OF MOLECULAR EVOLUTION."
Although I have called this book "the structure of evolutionary theory," I have
propagated my own lamentable parochialism under a pretense of generality. For
this book, despite its exuberant length, largely restricts itself to the Darwinian
tradition of conventional causal explanations based on selection as a central
mechanism. I do, to be sure, treat the major critiques of unbridled selectionism
(constraints as channels, failure of pure extrapolationism into geological time), but
I conduct this discussion within a Darwinian world, and do not adequately consider
truly alternative mechanisms of change and their domains of operation. Since
selection is a causal theory of change based on distinctive traits of definable
individuals within specified environments (quite apart from any stochastic sources
for the variation that provides raw materials of change), the obvious first-line
alternative to selection must lie in random reasons for change itself.
As a basic statement in the logic of an argument, this point can hardly be
denied, and therefore enjoys a long history of recognition in evolutionary thought.
But recognition scarcely implies acceptance. The Victorian age, basking in the
triumph of an industrial and military might rooted in technology and mechanical
engineering, granted little conceptual space to random events, so the issue barely
arose in Darwin's own time. (Darwin got into enough trouble by invoking
randomness for sources of raw material; he wasn't about to propose stochastic
causes for change as well! To this day, a distressingly familiar vernacular
misunderstanding of Darwinism rests upon confusing these two components
(sources of raw material and causes of change)—as in the common charge that
Darwinism must be wrong because human complexity couldn't arise by purely
random processes. Nineteenth
- Anyone, like me, who grew up in America with fiercely traditional immigrant
grandparents from "the old country" will appreciate the humor of such limited and
inappropriate reference points. My grandmother's only concern for any cultural or
historical event (all of which she followed with great interest and intensity) stood out in
her single, invariant question: "Is it good for the Jews?"