over concept--and Darwin wrote to Fawcett to counteract this odd
but effective mythology. Scientists often strive for special status by
claiming a unique form of objectivity inherent in a supposedly universal
procedure called the scientific method. We attain this objectivity
by clearing the mind of all preconception and then simply seeing, in a
pure and unfettered way, what nature presents. This image may be beguiling,
but the claim is chimerical and ultimately haughty and divisive. For the
myth of pure perception raises scientists to a pinnacle above all other
struggling intellectuals, who must remain mired in constraints of culture
and psyche.
But followers of the myth are ultimately hurt and limited, for the immense
complexity of the world cannot be grasped or ordered without concepts.
"All observation must be for or against some view if it is to be
of any service!" Objectivity is not an unobtainable emptying of mind
but a willingness to abandon a set of preferences when the world seems
to work in a contrary way.
This Darwinian theme of necessary interaction between theory and observation
gains strong support from a scientist's standard "take" on the
value of original theories. Sure, we love them for the usual "big"
reasons--because they change our interpretation of the world and lead
us to order things differently. But ask any practicing scientist, and
you will probably get a different primary answer, for we are hung up on
the details and rhythms of our daily work, and we don't think about ultimates
very often. We love original theories because they suggest new, different,
and tractable ways to make observations. By posing new questions, they
expand our range of ordinary activity. Theories drive us to seek new information
that only becomes relevant as data either for or against a hot idea. Data
adjudicate theory, but theory also drives and inspires data. Both Kant
and Darwin were right.
I bring up this personal favorite among quotations because my profession
of paleontology has recently witnessed a fine example of theory confirmed
by data that no one ever thought of collecting before the theory itself
demanded such a test. (Please note the fundamental difference between
demanding a test and guaranteeing the result. The test might just as well
have failed, thus dooming the theory. Good theories invite a challenge
but do not bias the outcome. In this case, the test succeeded twice, and
the theory has gained strength.) Ironically, this particular new theory
would have been anathema to Darwin himself, but such a genial and generous
man would, I am sure, have gladly taken his immediate lumps in exchange
for such a fine example of his generality about theory and observation,
and for the excitement of any idea so full of juicy implications.
We have known since the dawn of modern paleontology that short stretches
of geological time feature extinctions of substantial percentages of life--up
to 96 percent of marine invertebrate species in the granddaddy of all
such events, the late Permian debacle some 225 million years ago. These
"mass extinctions" were originally explained, in a literal and
commonsense sort of way, as products of catastrophic events, and therefore
truly sudden. As Darwin's idea of gradualistic evolution replaced this
earlier catastrophism, paleontologists sought to mitigate the evidence
of mass dying with a reading more congenial to Darwin's preference for
slow and steady. The periods of enhanced extinction were not denied--how
could they be in the face of such evidence?--but they were reinterpreted
as more spread out in time and less intense in effect: in short, as intensifications
of ordinary processes, rather than impositions of true and rare catastrophes.
In the Origin of Species (1859), Darwin rejected "the old
notion of all the inhabitants of the earth having been swept away at successive
periods by catastrophes," as well he might, given the extreme view
of total annihilation, with its antievolutionary implication of a new
creation to start life again. But Darwin's preferences for gradualism
were also extreme and false:
We have every reason to believe . . . that species and groups of species
gradually disappear, one after another, first from one spot, then from
another, and finally from the world.
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