Geoscience Reference
In-Depth Information
is not the only, and certainly not the complete, key to the past. How
was this seemingly obvious point ignored? Largely because of the
influence of Charles Lyell.
Born in 1797, the year that Hutton died, Lyell, through his
Prin-
ciples of Geology,
became the most influential geological writer of all
time.
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He was a lawyer who knew how to frame an argument, and
his treatise, presented as a textbook, was in fact a "passionate brief
for a single, well-formed argument, hammered home relentlessly," as
Stephen Jay Gould has described it.
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Lyell believed with Hutton
that God designed the earth for human beings, but that once He set
the earth on its path, He never again intervened in its workings.
Natural laws were invariant. The processes that we observe today,
and only those processes, have been in operation since the begin-
ning. Natural law and process are constant. In Lyell's philosophy
there were no more things in heaven than there were on the earth;
he needed no "help from a comet" to explain earthly processes.
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Lyell also believed that the rate at which geologic processes
acted was constant. He wrote, "If in any part of the globe the
energy of a cause appears to have decreased, it is always probable
that the diminution of intensity in its action is merely local, and
that its force is unimpaired, when the whole globe is considered."
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He meant that violent upheavals in one part of the earth are offset
and averaged out by quiescence elsewhere, leaving the overall rate
of change over time the same. Drastic change therefore, like all pol-
itics, is local.
Given Lyell's belief that neither natural law, the kinds of pro-
cesses that affect the earth, nor their rate, ever change, it is not sur-
prising to find that he also believed that the earth has always
looked as it does now, its history revealing no evidence of direc-
tional change. The pterodactyl is gone, true, but when climatic con-
ditions are again favorable, it may return to "flit again through the
umbrageous groves of treeferns."
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The earth always remains in the
same state, neither progressing nor deteriorating.
We can divide Lyell's thesis into the constancy of law and process,
and the constancy of rate and state. In what Gould has called "the
greatest trick of rhetoric ... in the entire history of science,"
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Lyell
gave them all the same name—
uniformity
—thus obscuring the funda-
mental difference between them for well over a century. William
Whewell, who reviewed the second volume of Lyell's topic, lumped
his two meanings together under the unwieldy term
uniformitarian-
ism.
(He also coined the word
scientist.)
Whewell asked whether "the
changes which lead us from one geological state to another have been,
on a long average, uniform in their intensity, or have they consisted of
