Pattern and Progress on the Geological Stage 499
Darwin, as I have emphasized throughout, was dogged and relentless, fiercely
honest and logical in his thinking. He wrestled with every major difficulty,
working and reworking, fretting and fretting again, until he achieved closure or at
least understood why a solution eluded him. He often became obsessed with
problems (levels of selection, for example) that his supporters either didn't grasp at
all, or didn't understand as sources of interest or trouble. Sometimes, as with
Kelvin, he probably worried an issue too far, but when we grasp the source of his
exaggerated concern, we understand the logic of his theory in a more complete
way.
Darwin's opposition to Kelvin has been well recorded, but the missing piece
in this historical puzzle, and the key for revising the false but canonical version of
this story as a morality play, lies in Darwin's loneliness. I have cited the
approbation of most geologists for Kelvin's efforts, but when we note the similar
acquiescence of Darwin's two major English supporters—Huxley and Wallace—
then the story becomes even more interesting (and the falsity of the conventional
version even more apparent).
Huxley devoted his 1868 presidential address for the Geological Society of
London to defending this profession against Kelvin's charges. Yet by Huxleyan
standards—as the greatest literary polemicist (equalled, perhaps, by Buffon) in the
history of biology—this particular address packs little punch. Huxley does not
assert a distinctive geological way of thought against Kelvin's unwelcome
intrusions. Instead, he simply accepts Kelvin's claims, and defends geology only
against Kelvin's characterizations. No one, he argues, not even Lyell (who had, by
then, abandoned uniformity of state by admitting vectors in the history of life),
maintains so strict and comprehensive a view of uniformity. In fact, the old
dichotomy of uniformity vs. catastrophe has largely been swept aside, with both
views yielding to an "evolutionism" based on slow, continuous and directional
change on an ancient earth.
Huxley argues that neither of Kelvin's two major claims contradicts this new,
evolutionist synthesis. Geologists can accept Kelvin's directionalism because
uniformitarianism has abandoned any former flirtation with the doctrine of an earth
in steady state. Geologists would be distressed by a truly serious limitation upon
time, but 100 million years provides more than sufficient amplitude for any
legitimate geological purpose.
Coming to his key point, Huxley allows that some people (he does not
mention his friend Darwin by name) feel a tug between Kelvin's dates and a greater
age supposedly implied by the extreme slowness of evolutionary change. But this
feeling, Huxley assures us, cannot be defended. We can only assess the speed of
evolution by calibration against elapsed geological time. Previous assertions of
extreme slowness flowed from geological convictions about immensity—as no
purely biological data exist for a truly independent calibration. If Kelvin has now
demonstrated that time must be shorter, we can only conclude that evolution has
generally been faster.
But, it may be said that it is biology, and not geology, which asks for so
much time—that the succession of life demands great intervals; but this