The Fossil Fallacy:
Creationists' demand for fossils that represent "missing links" reveals a
deep misunderstanding of science
By Michael Shermer
Nineteenth-century English social scientist Herbert Spencer made this prescient
observation: "Those who cavalierly reject the Theory of Evolution, as not
adequately supported by facts, seem quite to forget that their own theory
is supported by no facts at all." Well over a century later nothing has changed.
When I debate creationists, they present not one fact in favor of creation
and instead demand "just one transitional fossil" that proves evolution.
When I do offer evidence (for example, Ambulocetus natans, a transitional
fossil between ancient land mammals and modern whales), they respond that
there are now two gaps in the fossil record.
This is a clever debate retort, but it reveals a profound error that I call
the Fossil Fallacy: the belief that a "single fossil"--one bit of
data--constitutes proof of a multifarious process or historical sequence.
In fact, proof is derived through a convergence of evidence from numerous
lines of inquiry--multiple, independent inductions, all of which point to
an unmistakable conclusion.
We know evolution happened not because of transitional fossils such as A.
natans but because of the convergence of evidence from such diverse fields
as geology, paleontology, biogeography, comparative anatomy and physiology,
molecular biology, genetics, and many more. No single discovery from any
of these fields denotes proof of evolution, but together they reveal that
life evolved in a certain sequence by a particular process.
One of the finest compilations of evolutionary data and theory since Charles
Darwin's On the Origin of Species is Richard Dawkins's magnum opus, The
Ancestor's Tale: A Pilgrimage to the Dawn of Evolution (Houghton Mifflin,
2004)--688 pages of convergent science recounted with literary elegance.
Dawkins traces numerous transitional fossils (what he calls "concestors,"
the last common ancestor shared by a set of species) from Homo sapiens back
four billion years to the origin of heredity and the emergence of evolution.
No single concestor proves that evolution happened, but together they reveal
a majestic story of process over time.
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We know evolution happened because of a convergence of evidence.
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Consider the tale of the dog. With so many breeds of dogs popular for so
many thousands of years, one would think there would be an abundance of
transitional fossils providing paleontologists with copious data from which
to reconstruct their evolutionary ancestry. In fact, according to Jennifer
A. Leonard, an evolutionary biologist then at the Smithsonian Institution's
National Museum of Natural History, "the fossil record from wolves to dogs
is pretty sparse." Then how do we know whence dogs evolved? In the November
22, 2002, Science, Leonard and her colleagues report that mitochondrial DNA
(mtDNA) data from early dog remains "strongly support the hypothesis that
ancient American and Eurasian domestic dogs share a common origin from Old
World gray wolves."
In the same issue, molecular biologist Peter Savolainen of the Royal Institute
of Technology in Stockholm and his colleagues note that even though the fossil
record is problematic, their study of mtDNA sequence variation among 654
domestic dogs from around the world "points to an origin of the domestic
dog in East Asia" about 15,000 years before the present from a single gene
pool of wolves.
Finally, anthropologist Brian Hare of Harvard University and his colleagues
describe in this same issue the results of a study showing that domestic
dogs are more skillful than wolves at using human signals to indicate the
location of hidden food. Yet "dogs and wolves do not perform differently
in a nonsocial memory task, ruling out the possibility that dogs outperform
wolves in all human-guided tasks," they write. Therefore, "dogs'
social-communicative skills with humans were acquired during the process
of domestication."
No single fossil proves that dogs came from wolves, but archaeological,
morphological, genetic and behavioral "fossils" converge to reveal the concestor
of all dogs to be the East Asian wolf. The tale of human evolution is divulged
in a similar manner (although here we do have an abundance of fossils), as
it is for all concestors in the history of life. We know evolution happened
because innumerable bits of data from myriad fields of science conjoin to
paint a rich portrait of life's pilgrimage.
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Michael Shermer is publisher of Skeptic (www.skeptic.com) and author of
The Science of Good and Evil.
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