Today, we ask if there was life before Clovis. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
Scientists are always at
their worst when they're most certain. Science
looks the way it's supposed to look only when it
faces mystery. When Dirac and de Broglie struggled
with particles and waves in the 1920s, that was
real combat with mystery.
It was just then, in the '20s, that another piece
of common wisdom began falling apart. In 1920, we
believed the age of human life in the Americas was
only a few thousand years. Then, in 1926, we found
remains at a site near Clovis, New Mexico. The site
held lots of tools -- and a few bones -- all from
the late glacial period. Anthropology riveted our
interest as the age of the first Americans suddenly
stretched to 12,000 years.
For half a century we turned up other sites of
comparable age, but none older. As the years
passed, scientific inquiry turned to conviction.
Twelve thousand years became a Maginot line that
anthropologists could not cross.
Now we're again finding what might be far older
sites. And scholars square off to do battle. The
result is, to my mind, the game of science at its
best. Let's look at the evidence:
Carbon dating tells us that mammoth bones in the
Yukon are 15 to 20 thousand years old. The bones
seem to have been worked by stone tools, but were
they, really? Remains in a Pennsylvania site are 13
to 20,000 years old. They include two human bones
whose age seems to be 12 to 14 thousand years. But
skeptics find ways to question the carbon dating.
We've found arrowheads among 13,000-year-old
mastodon bones in Venezuela. But they might've been
dumped there by rising water. Similar doubts cloud
similar findings in Chile.
The most notorious find of all is a recent one in
Brazil. An arrangement of charcoal could be a
campsite. It gives carbon dates over 30,000 years
old. But was it really a campsite?
The pervasive problem is the lack of a corpus
delicti. Where's the body? Until we find human
remains, it's easy to be skeptical. The trouble
with experimental proofs is, they aren't absolute.
Defenders of the old Clovis dates fall back on a
legal definition of proof, not a scientific one.
Instead of accepting the most likely conclusion,
they demand that we erase all reasonable doubt. And
that's something science can never do.
So we draw battle lines. So much scholarship has
rested on the Clovis dates. The new sites threaten
whole lifetimes of intellectual commitment. But,
however the contest should end, New-World
anthropology is back in the public domain. The game
is afoot again; and for that, knowledge is alive.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds