The Discovery of Deep Time - Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time - page 3

posed by Niles Eldredge and myself, is not, as so often misunderstood, a
radical claim for truly sudden change, but a recognition that ordinary
processes of speciation, properly conceived as glacially slow by the standard
of our own life-span, do not translate into geological time as long sequences
of insensibly graded intermediates (the traditional, or gradualistic, view), but
as geologically "sudden" origins at single bedding planes.
An abstract, intellectual understanding of deep time comes easily enough-I
know how many zeroes to place after the 10 when I mean billions. Getting it
into the gut is quite another matter. Deep time is so alien that we can really
only comprehend it as metaphor. And so we do in all our pedagogy. We tout
the geological mile (with human history occupying the last few inches); or
the cosmic calendar (with Homo sapiens appearing but a few moments before
Auld Lang Syne). A Swedish correspondent told me that she set her pet snail
Bjorn (meaning bear) at the South Pole during the Cambrian period and
permits him to advance slowly toward Malmo, thereby visualizing time as
geography. John McPhee has provided the most striking metaphor of all (in
Basin and Range): Consider the earth's history as the old measure of the
English yard, the distance from the king's nose to the tip of his outstretched
hand. One stroke of a nail file on his middle finger erases human history.
How then did students of the earth make this cardinal transition from
thousands to billions? No issue can be more important in our quest to
understand the history of geological thought.
Myths of Deep Time
Parochial taxonomies are a curse of intellectual life. The acceptance of deep
time, as a consensus among scholars, spans a period from the mid-
seventeenth through the early nineteenth centuries. As Rossi wrote (1984,
ix): "Men in Hooke's times had a past of six thousand years; those of Kant's
times were conscious of a past of millions of years." Since geology didn't
exist as a separate and