1214 THE STRUCTURE OF EVOLUTIONARY THEORY
of Darwinian central logic), if species gravitate to a position of best possible balance
between optimization for the moment and flexibility for future change, then
Darwinian organismic selection cannot directly fashion such adaptations with
advantages only measurable in terms of capacity for success in the face of future
environmental changes, a central component in Kauffman's concept of benefits
provided by residence at the edge of chaos (p. 409): "Selection, I shall further
suggest, by achieving genomic systems in the ordered regime near the boundary of
chaos, is likely to have optimized the capacity of such systems to perform complex
gene-coordination tasks and evolve effectively." A Darwinian can argue that
flexibility linked to future capacity for change arises exaptively as a lucky
consequence of features actively evolved for immediate organismic advantage. But
such capacities can also evolve by direct selection, at a higher level, for species-
individuals who win differential reproductive success by their propensity for living
through external crises that consign closely related species-individuals to extinction.
Exapting the Rich and Inevitable Spandrels of History
NIETZSCHE'S MOST IMPORTANT PROPOSITION
OF HISTORICAL METHOD
A. N. Whitehead famously remarked (see previous citation on p. 57) that all later
philosophy might well be described as a footnote to Plato. How often, indeed, must
any decent scholar invent a formulation with pride in systematic analysis, and with
hope for originality—only to discover that one of history's truly great thinkers had
established the same principle, recognized its importance, and even specified its full
range of application. I described a case of this ultimately humbling experience (see p.
51), when I discovered that, for all the struggles of several macroevolutionists, none
more intense than my own, to define a workable concept of species selection in the
1970's, Hugo de Vries had formulated the idea, and even applied the same name, in
his 1905 book, written in English and therefore scarcely qualifying as light hidden
under a bushel for anglophonic readers.
I knew that a claim for originality could never be asserted for my various
writings on the key structural and historical principle of inherent differences between
current utility and causes of origin, and on the consequent impossibility of inferring
reasons for evolutionary construction only from current adaptive roles (Darwin, after
all and as we shall see (pp. 1218-1224), invoked this principle to disperse a
theoretical objection that he regarded as the most potent challenge to the central logic
of natural selection). I have written about this subject for more than 30 years, and
with a growing attempt at systematization, moving from my naive, albeit accurate,
distinction of "immediate" and "retrospective" significance in Ontogeny and
Phylogeny (1977b), to the spandrels of San Marco (Gould and Lewontin, 1979), to
the codification of exaptation as a missing term in the science of form (Gould and
Vrba, 1982). Only my work on punctuated equilibrium has attracted more citations,