THREE CENTURIES' PERSPECTIVES 399
erectus populations, and then spread out later to cover the globe—
the so-called out-of-Africa view?
The tides of argument have swung back and forth, but recent
evidence seems to be cascading toward Out of Africa. As more and
more genes are sequenced and analyzed for their variation among
human racial groups, and as we reconstruct genealogical trees based
upon these genetic differences, the same strong signal and pattern
seem to be emerging: Homo sapiens arose in Africa; the migration
into the rest of the world did not begin until 112,000 to 280,000
years ago, with the latest, more technologically sophisticated studies
favoring dates near the younger end of this spectrum.
In other words, all non-African racial diversity—whites, yellows,
reds, everyone from the Hopi to the Norwegians, to the Fijians—
may not be much older than one hundred thousand years. By con-
trast, Homo sapiens has lived in Africa for a longer time. Conse-
quently, since genetic diversity roughly correlates with time
available for evolutionary change, genetic variety among Africans
alone exceeds the sum total of genetic diversity for everyone else in
the rest of the world combined! How, therefore, can we lump "Afri-
can blacks" together as a single group, and imbue them with traits
either favorable or unfavorable, when they represent more evolu-
tionary space and more genetic variety than we find in all non-
African people in all the rest of the world? Africa is most of human-
ity by any proper genealogical definition; all the rest of us occupy a
branch within the African tree. This non-African branch has surely
flourished, but can never be topologically more than a subsection
within an African structure.
We will need many years, and much pondering, to assimilate
the theoretical, conceptual, and iconographic implications of this
startling reorientation in our views about the nature and meaning
of human diversity. For starters, though, I suggest that we finally
abandon such senseless statements as "African blacks have more
rhythm, less intelligence, greater athleticism." Such claims, apart
from their social perniciousness, have no meaning if Africans can-
not be construed as a coherent group because they represent more
diversity than all the rest of the world put together.
Our greatest intellectual adventures often occur within us—not
|n the restless search for new facts and new objects on the earth or
the stars, but from a need to expunge old prejudices and build