Charles Lyell, Historian of Time's Cycle - Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time - page 176

have punctuated the history of life. It removed the dinosaurs and their kin,
along with some 50 percent of all marine species.
Lyell's gradualism has acted as a set of blinders, channeling hypotheses in
one direction among a wide range of plausible alternatives. Its restrictive
effects have been particularly severe for those geologists who succumb to
Lyell's rhetorical device and believe that gradual change is preferable (or
even required) a priori because different meanings of uniformity are
necessary postulates of method. Again and again in the history of geology
after Lyell, we note reasonable hypotheses of catastrophic change, rejected
out of hand by a false logic that brands them unscientific in principle. Thus, J
Harlen Bretz's correct hypothesis for the formation of Washington's
channeled scablands by catastrophic flooding was long dismissed by
uniformitarians, who sought more time and many smaller rivers on little basis
beyond a stated repugnance for catastrophes (several detractors at the famous
1927 confrontation between Bretz and scientists of the U.S. Geological
Survey admitted that they had never visited the area, but were quite willing to
propose gradualist alternatives as preferable a priori —see Baker and
Nummedal, 1978; Gould, 1980). And the New York Times, in its editorial
pages no less, has proclaimed that extraterrestrial impact as a catastrophic
cause of the Cretaceous-Tertiary extinction has no place in science:
"Terrestrial events, like volcanic activity or change in climate or sea level,
are the most immediate possible cause of mass extinctions. Astronomers
should leave to astrologers the task of seeking the causes of earthly events in
the stars" (April 2, 1985).
Yet the Alvarez hypothesis of asteroidal or cometary impact is a powerful
and plausible idea rooted in unexpected evidence of a worldwide iridium
layer at the Cretaceous-Tertiary boundary, not developed from an anti-
Lyellian armchair. It must be tested in the field, not dismissed a priori. In this
light, and as a final example of how Lyell's rhetorical confusion might stifle
legitimate research, I note Lyell's harsh dismissal of the seventeenth-century
scientist William Whiston, because he dared to promote comets, and not