Geology Reference
In-Depth Information
often stated, a textbook summarizing all prevailing knowledge in a
systematic way, but a passionate brief for a single, well-formed argument,
hammered home relentlessly. All sections of the text, including the
introductory history, push the same theme, while the order of sections also
records the smoothly unfolding brief. The famous sentence penned by
Darwin to introduce the last chapter of the Origin of Species would serve as
well for Lyell's three installments: "this whole volume is one long argument."
Roughly characterized, Lyell holds that geological truth must be unraveled
by strict adherence to a methodology that he did not name, but that soon
received the cumbersome designation of "uniformitarianism" (in a review by
William Whewell, written in 1832). Lyell captured the essence of uniformity
in the subtitle to his treatise: "an attempt to explain the former changes of the
earth's surface by reference to causes now in operation." The proposition
seems simple enough. Science is the study of processes. Past processes are, in
principle, unobservable; only their frozen results remain as evidence for
ancient history—fossils, mountains, lavas, ripple marks. To learn about past
processes, we must compare these past results with modern phenomena
formed by processes that we can observe directly. In this sense, the present
must be our key to the past (Figure 4.2).
If Lyellian uniformity only advocated this evident statement of method, it
would be uncontroversial and not particularly enlightening. But Lyell held a
complex view of uniformity that mixed this consensus about method with a
radical claim about substance—the actual workings of the empirical world.
Lyell argued that all past events—yes, every single one—could be explained
by the action of causes now in operation. No old causes are extinct; no new
ones have been introduced. Moreover, past causes have always operated—
yes, always—at about the same rate and intensity as they do today. No
secular increases or decreases through time. No ancient periods of pristine
vigor or slow cranking up. The earth, in short, has always worked (and
looked) just about as it does now. (I shall present a taxonomy of the various,
and partly contradictory, mean-
Search WWH ::




Custom Search