many scientists would now view as unduly restrictive in their designation of a
privileged locus of causality, a single direction of causal flow, and a smooth
continuity in resulting effects. Classical Darwinism follows standard reductionist
preferences in designating the lowest level then available—the organism, for
Darwin—as an effectively unique locus of causality (the first leg of agency). In
this sense, the efforts of Williams and Dawkins (see Chapter 8) to reduce the
privileged locus even further to the genie level (perforce unavailable to Darwin)
should be read as a furthering and intensification of Darwin's intent—in other
words, a basically conservative adumbration of Darwin's own spirit and arguments,
and not the radical conceptual revision that some have imagined.
At this single level of causality, classical Darwinism then envisages a
similarly privileged direction of causal flow, as information from the environment
(broadly construed, of course, to include other organisms as well as physical
surroundings) must impact the causal agent (organisms struggling for reproductive
success) and be translated, by natural selection, into evolutionary change. The
organism supplies raw material in the form of "random" variation, but does not
"push back" to direct the flow of its own alteration from inside. Darwinism, in this
sense, is a functionalist theory, leading to local adaptation as the environment
proposes and natural selection disposes. Finally, classical Darwinism completes a
trio of privileged causal places and consequently directional flows by postulating
strict continuity in results, as local selection scales smoothly through the
immensity of geological time to engender life's history by pure extrapolation of
lowest-level modes and causes.
By contrast, the common themes behind the reformulations defended in this
book all follow from serious engagement with complexity, interaction, multiple
levels of causation, multidirectional flows of influence, and pluralistic approaches
to explanation in general—a set of integrated approaches that strongly contribute to
the Zeitgeist of our moment. To anticipate and make a preemptive strike against
the obvious counterattack from Darwinian traditionalists, these alternative themes
do not substitute a "laid back, laissez-faire, anything goes" kind of sloppy tolerance
for contradiction and fuzziness in argument against the genuine rigor of old-line
Darwinism. The social and psychological contributions of a Zeitgeist to the origin
of hypotheses bear no logical relationship to any subsequent scientific defense and
validation of the same hypotheses. Moreover, on this subject of test and
confirmation, I espouse a rigorously conventional and rather old-fashioned "realist"
view that an objective factual world exists "out there," and that science can access
its ways and modes. Whatever the contribution of a Victorian Zeitgeist to Darwin's
thinking, or of a contemporary Zeitgeist to our revisions, the differences are
testable and subject to validation or disproof by the usual armamentarium of
scientific methods. That is, either Darwin is right and effectively all natural
selection occurs at the organismic level (despite the logical conceivability of other
levels), or the hierarchical theory is right and several levels make interestingly
different and vitally important simultaneous con-
32 THE STRUCTURE OF EVOLUTIONARY THEORY