I have, so far, only
presented the negative evidence for my thesis that human equality is a contingent
fact of history. I have argued that the old bases for inequality have evaporated.
I must now summarize the positive arguments (primarily three in number) and, equally
important, explain how easily history might have happened in other ways.
The positive argument from racial definition. In one of the first
columns of this series (March 1974), I presented the biological argument against
naming races within any species, and within H. sapiens in particular. The
argument is technical and taxonomic; it has nothing to do with human particularities
or ethical impositions. Its précis follows:
only one formal category for divisions within species--the subspecies. Races,
if formally defined, are therefore subspecies. Subspecies are populations inhabiting
a definite geographic subsection of a species' range and sufficiently distinct
in any set of traits for taxonomists to recognize them. Subspecies differ from
all other levels of the taxonomic hierarchy in two crucial ways. First, they are
categories of convenience only and need never be designated. Each organism must
belong to a species, a genus, a family, and to all higher levels of the hierarchy;
but a species need not be formally divided. Subspecies represent a taxonomist's
personal decision about the best way to report geographic variation. Second, the
subspecies of any species cannot be distinct and discrete. Since all belong to
a single species, their members can, by definition, interbreed. Modern quantitative
methods have permitted taxonomists to describe geographic variation more precisely
in numerical terms; we need no longer construct names to describe differences
that are, by definition, fleeting and changeable. Therefore, the practice of naming
subspecies has largely fallen into disfavor, and few taxonomists use the category
any more. Human variation exists; the formal designation of races is passé.
Some species are divided into tolerably distinct geographic races.
Consider, for example, an immobile species separated on drifting continental blocks.
Since these subpopulations never meet, they may evolve substantial differences.
We might choose to name subspecies for such discrete geographic variants. But
humans move about and have the most notorious habits of extensive interbreeding.
We are not well enough divided into distinct geographic groups, and the naming
of human subspecies makes little sense.
Our variation is subject
to all the difficulties and discordances that make taxon omists shudder (or delight
in complexity) and avoid the naming of subspecies. Consider just three points.
First, discordance of characters. We might make a reasonable division on skin
color, only to discover that blood groups imply different alliances. When so many
good characters have such discordant patterns of variation, no valid criterion
can be found for unambiguous definition of subspecies. Second, fluidity and gradations.
We interbreed wherever we move, breaking down barriers and creating new groups.
Shall the Cape Colored, a vigorous people more than two million strong and the
offspring of unions between Africans and white settlers (the ancestors, ironically,
of the authors of apartheid and its antimiscegenation laws), be designated a new
subspecies or simply the disproof that white and black are very distinct? Third,
convergences. Similar characters are independently evolved again and again; they
confuse any attempt to base subspecies on definite traits. Most indigenous tropical
people, for example, have evolved dark skin.
The arguments against
naming human races arc strong, but our variation still exists and could, conceivably,
still serve as a basis for invidious comparisons. Therefore, we need the second
and third arguments as well.
The positive argument from recency
of division. As I argued in the first part of this essay (and need only state
in repetition now), the division of humans into modern "racial" groups
is a product of our recent history. It does not predate the origin of our own
species, Homo sapiens, and probably occurred during the last few tens (or
at most hundreds) of thousands of years.
The positive argument
from genetic separation. Mendel's work was rediscovered in 1900 and the science
of genetics spans our century. Yet, until twenty years ago, perhaps the most important
question in evolutionary genetics could not be answered for a curious reason.
We were not able to calculate the average amount of genetic difference between
organisms because we had devised no method for taking a random sample of genes.
In the classical Mendelian analysis of pedigrees, a gene cannot be identified
unless it varies among individuals. For example, if absolutely every Drosophila
in the world had red eyes; we would rightly suspect that some genetic information
coded this universal feature, but we would not be able to identify it by analyzing
pedigrees, because all flies would look the same. But as soon as we find a few
white-eyed flies, we can mate white with red, trace pedigrees through generations
of offspring, and make proper inferences about the genetic basis of eye color.
To measure the average genetic differences among races, we must
be able to sample genes at random--and this can't be done if we can only identify
variable genes. Ninety percent of all genes might be held in common by all people,
and an analysis confined to varying genes would grossly overestimate the total
In the late 1960s, several geneticists harnessed
the common laboratory technique of electrophoresis to solve this old dilemma.
Genes code for proteins, and varying proteins may behave differently when subjected
in solution to an electric field. Any protein could be sampled, independent of
prior knowledge about whether it varied or not. (Electrophoresis can only give
us a minimal estimate because some varying proteins may exhibit the same electrical
mobility but be different in other ways.) Thus, with electrophoresis we could
finally ask the key question: how much genetic difference exists among human races?
The answer, surprising for many people, soon emerged without ambiguity:
damned little. Intense studies for more than a decade have detected not a single
"race gene"--that is, a gene present in all members of one group
and none of another. Frequencies vary, often considerably, among groups, but all
human races are much of a muchness. Variation among individuals within
any race is so great that we encounter very little new variation by adding another
race to the sample. In other words, the great preponderance of human variation
occurs within groups, not in the differences between them. My colleague Richard
Lewontin, who did much of the original electrophoretic work on human variation,
and whose recent book, Human Diversity (Scientific American Library, 1982),
may be consulted for the details, puts it dramatically: if, God forbid, the holocaust
occurs "and only the Xhosa people of the southern tip of Africa survived,
the human species would still retain 80 percent of its genetic variation."
As long as most scientists accepted the ancient division of races,
they expected important genetic differences. But the recent origin of races (second
positive argument) squares well with the minor genetic differences now measured.
Human groups do vary strikingly in a few highly visible characters (skin color,
hair form)--and this may fool us into thinking that overall differences must
be great. But