1304 THE STRUCTURE OF EVOLUTIONARY THEORY
Thus, for example, when Gilluly (1949) published one of the most famous and
influential geological papers of the mid-twentieth century, arguing that one popular
physical theory for mass extinction—episodes of orogeny, or mountain building—
could not be construed as either global in effect or simultaneous in occurrence on all
continents, but should rather be interpreted as sequences of more limited local events
liberally spread out in time, he ended his paper with a stirring manifesto: "Long live
Charles Lyell and his doctrine of uniformitarianism!" And, if I may cite an
embarrassing incident from my own graduate career, when my mentor Norman
Newell decided to invest considerable effort in compiling data from faunal lists in the
world's paleontological literature to see if the maligned and effectively abandoned
theme of mass extinction held any validity, I thought that the old man had taken leave
of his good scientific sense in wasting so much time on a truly settled issue. For didn't
we all know that the extinctions really spanned considerable intervals of time, and
that any blip detected from faunal lists could only be recording an artifact of longer
periods artificially compressed into simultaneity by imperfections of the fossil
record?
Only with this understanding of the historical impact and persistence of
Darwin's uniformitarian and extrapolationist view of extinction in the fossil record
can we grasp the conceptual reforming power (and not merely the phenomenological
fascination) of the improving case—from a wild idea rejected out of hand by nearly
all paleontologists in 1980, to a firmly documented virtual fact of nature by 2000—
for the triggering of at least one mass extinction, the Cretaceous-Tertiary event, by
impact of a large extraterrestrial object (see Alvarez et al., 1980, for the original
proposal, and Glen, 1994, for history of science in progress in a book entitled: The
Mass Extinction Debates: How Science Works in a Crisis).
Two comments on the K-T (Cretaceous-Tertiary) transition, one new and one
old, may be taken as emblematic of the magnitude of both theoretical and practical
reformulation. First, M. J. S. Rudwick, a prominent systematist of fossil brachiopods
early in his career and the world's leading historian of geology in later years,
commented to Glen with the professional skills and "feel" of both segments of his
ontogeny: "It never crossed my mind that... the brachiopod groups I worked with
expired suddenly by modern K/T boundary standards. I thought that the brachs went
out suddenly, but that 'suddenly'... in 1967 meant a few million years, which was
considered geologically sudden" (quoted in Glen, 1994, p. 41).
Second, an argument prominently advanced by Charles Lyell himself
dramatically illustrates the difference between strictly uniformitarian expectations
and the implications of truly catastrophic triggers for mass extinction.
slight inducement, has renounced his heretical belief in the earth's motion, perhaps students
of physics will return to the practical problems of armaments and navigation, and leave the
solution of cosmological problems to those learned in the infallible sacred texts." I also
suggested that, as a quid pro quo of ultimate fairness, the Times might award to the
Paleontological Society the right to determine the date and amount of their next price
increase