earth’s atmosphere thirteen thousand years ago, setting much of North America
on fire. Possibly the resulting firestorm killed off the larger mammals, like
horses and mastodons, and decimated the human population.^11
“Possibly,” however, does not fit with textbook style, which is to present
definitive answers. Only The American Adventure admits uncertainty: “This
page may be out of date by the time it is read.” Adventure goes on to present
competing claims that humans have been in the Americas for twelve thousand,
twenty-one thousand, and forty thousand years. As a result, although Adventure
is one of the oldest of all the textbooks I surveyed, its pre-Columbian pages
have not gone out of date.^12 Most other textbooks retain their usual
authoritative tone. Regarding the date of the first human settlement of the
Americas, estimates vary from twelve thousand years before the present to
more than seventy thousand BP.^13 Some scientists believe that the original
settlers came in successive waves over thousands of years; genetic similarities
convince others that most Natives descended from a single small band.^14 Most
textbook authors simply choose one date and present it as undisputed fact.
Some newer books add “probably,” as in: people “probably followed the
animal herds,” from Holt American Nation. But then, like the others, they
supply one date for students to memorize.
Authors need to go further. Walking across Beringia (the isthmus across the
Bering Strait) is only a hypothesis. They ought to give other theories, including
boats, a hearing. They would not have to do all the work themselves, either, but
could set students loose on the Web and in the library, arming them and their
teachers with ideas about what to look for and how to assess reputed new
findings. The school year might then begin with a debate among students who
have chosen different dates and routes—each marshaling evidence from
glottochronology (dating linguistic changes), genetics, archaeology, and other
disciplines to bolster their conclusion. Students would be excited. They would
realize, at the start, that history still remains to be done—that it is not just an
inert body of facts to be memorized.
We can see the absence of intellectual excitement from the beginning. How
did people get here? Every book says something like this, from Boorstin and
Kelley:
So much of the earth’s water had frozen into ice that it lowered
the level of the sea in the Bering Strait. Then as they tracked