The Essence of Darwinism and the Basis of Modern Orthodoxy 103
documentation. The Origin therefore focuses upon the establishment of a
methodology for making inferences about history from features of modern
organisms—and then using these multifarious inferences to prove both the fact of
evolution and the probability of natural selection as a primary mechanism of
change.
A Fourfold Continuum of Methods for the Inference of History
OF HISTORY
Darwin, as a subtle and brilliant thinker, must be read on several levels. Consider
just three, at decreasing domains of overt display, but increasing realms of
generality: On the surface—a lovely, and not a pejorative, location for any student
of nature—each book treats a particular puzzle: different forms of flowers on the
same plant (1877), modes of formation for coral atolls (1842), formation of soil by
worms (1881), styles of movement in climbing plants (1880a), the fertilization of
orchids by insects (1862). At an intermediary level, as Ghiselin (1969) showed in
his innovative study of the entire Darwinian corpus, each book forms part of a
comprehensive argument for evolution itself. But I believe that we must also
recognize a third, even deeper and more comprehensive layer of coordinating
generality—Darwin's struggle to construct and apply a workable method for
historical inference: a series of procedures offering sufficient confidence to place
the sciences of history on a par with the finest experimental work in physics and
chemistry. I have come to regard each of Darwin's books as, all at the same time, a
treatment of a particular puzzle (level one), an argument for an evolutionary
worldview (level two), and a treatise on historical methodology (level three). But
the methodological focus of level three has usually been overlooked because
Darwin chose to work by practice rather than proclamation.
Darwin recognized that several methods of historical inference must be
developed, each tailored to the nature and quality of available evidence. We may
order his procedures by decreasing density of available information. I recognize
four waystations in the continuum and argue that each finds a primary illustration
in one of Darwin's books on a specific puzzle in natural history. The Origin of
Species, as his comprehensive view of nature, uses all four methods, and may
therefore be read as a summation of his seminal contribution to the methodology of
historical science. I shall list, and then illustrate with examples from the Origin,
these four principles ordered by decreasing density of information.
UNIFORMITY. Or working up by extrapolation from direct observations on
rates and modes of change in modern organisms. Call this, if you will, the worm
principle to honor Darwin's last book (1881), which explains the topsoil and
topography of England by extrapolating the measured work of worms through all
scales of time, from the weight of castings left daily on a patch of sod to the
historical and geological realms of millennia to millions of years.
SEQUENCING. Or the definition and ordering of various configurations,