Seeds of Hierarchy 191
change introduces the oddness and unpredictability of contingency. We can never
know exactly what climatic change will occur, which lineage will be diverted into
its channel, and how the resulting adaptation will form. Thus, our actual world
becomes filled up with unique particulars. Giraffe necks do not arise by first
principles of natural law, but as a contingency of dry climates and acacia trees at a
particular time and place.
TIMELESS VS. HISTORICAL. History requires distinctive moments that tell a
story as a sequence of events. The force of progress may confer history upon any
particular bolus of protoplasm as it mounts the ladder. But, in a larger sense, this
force also cancels the usual meaning of history. Each step becomes predictable and
repeatable; and each exists at every time (since spontaneous generation continually
replenishes the base). Thus, Lamarck's perfecting force becomes essentially
ahistorical. The rungs of the ladder are permanent and always occupied; items pass
up and through, but the forms are timeless. Genuine history enters via the
disturbing force of environmental adaptation instead. A mole without eyes, a stork
with long legs, a duck with webbed feet—all originate as nonrepeatable objects of
a historical moment, triggered by a particular change of environment in a unique
time and place.
HIGHER TAXA VS. SPECIES AND GENERA. Lamarck's two-factor theory is
hierarchical. The force of progress—paramount, primary, and underlying—
produces patterns of nature at the broadest scale, and therefore forges the
relationships among higher taxa in our classifications. The force of adaptation is
secondary, disruptive, and subsidiary. It seizes individual lineages and pulls them
from the main Sequence into side channels that always peter out as dead ends. This
lower-level force produces the smaller units, the species and genera of our
taxonomies.
ELUSIVE VS. PALPABLE. This last antinomy does not form part of Lamarck's
scheme, but becomes important in later interpretations, particularly in Darwin's
refutation. The force of progress lies deeper within and operates at a higher level;
the force of adaptation works palpably at the surface of things. One can, at least in
principle, observe climates getting colder and elephants growing thick coats of fur
in direct response; but advance up the ladder lies further from our view in an
abstract distance. Lamarck might have denied that the causes of progress posed any
greater difficulty in recognition and observation; in his conceptual world, these
forces arose from the chemical nature of matter—and therefore became just as
accessible as the immediate causes of adaptation. But when Lamarck's theories of
physical causation collapsed, the force of progress became elusive—something
operating so slowly, and at such high taxonomic levels, as to be effectively
invisible in the here and now of testable science. Darwin based his theory upon a
reformulation of this seventh antinomy—by arguing that palpable and immediate
forces of adaptation did not oppose an inscrutable and untestable force of
progress—but rather became the source of progress as well (and hence the only
primary cause of all evolution) when extrapolated, by principles of
uniformitarianism, into the immensity of time. All evolution therefore entered the
realm of the testable.