I wrote that in the post below. In the comments section Eileen wondered what might be behind such a bald statement:
JJC--can you elaborate on this, especially in relation to excerpt I shared from Pinker? I was thinking, too, especially viz. Meg's comments: do we need to define more precisely what we mean by "race"? ... I feel that there is a kind of bio-spectral leftover we're still not dealing with quite adequately somehow.
And here's the problem: race is exceptionally difficult to define. Everyone knows what they mean by race, but ask them try to articulate what they mean by the word and "race" dissolves into contradiction and incoherence (kind of like Augustine complaining about defining "time"). Is race skin color? Physiology? Susceptibility to certain diseases? Geographic origin? Genetic variation? It's tough to make the concept stick to any of those categories in a coherent way, except via fantasy and unexamined belief.
Don't buy that? My colleague at GW, Gayle Wald, provides from a cultural studies point of view a succinct survey of race as a mode of representation rather than an essence. See the introduction to her book Crossing the Line: racial passing in 20th C US Literature and Culture. The starting point for much of the influential field of criticism called Critical Legal Studies is likewise that race is a category that must be constantly reified (especially legislatively) because it doesn't actually pre-exist such reification, except as an incoherent mass of assumption tacked to shifting physical criteria.
The American Anthropological Association issued a Statement on "Race" in 1998 that rebuked most common conceptualizations of what race consists of, implicitly rejecting the category's utility. The New England Journal of Medicine published an editorial in 2001 that stated bluntly "race is a social construct, not a scientific classification" (NEJM 344  1392-93). Nature Genetics published a special, web-available issue on "Genetics for the Human Race" that looks closely at race and the human genome. Most of the articles conclude that race is not an easily identified genetic presence. Here is an excerpt from the foreword by Ari Patrinos:
If 'race' as a concept is oversimplified, what can or should we use to describe and define our heritage or familial lineage? Ethnicity, genetics, ancestry, lineage and family all denote something about our origins, but what? Perhaps the more immediate question is whether the completed Human Genome Project will define a concept of race that is scientifically credible and useful. Can a more thorough look at the genetic complement, the actual DNA sequences we each carry, clarify and inform our history and relationships? At the simplest level, each of us carries a set of genes that affects the color of his or her skin (often a surrogate for race). The exact number of these genes isn't known (PLoS Biology 1, 19−22; 2003), but they represent only a small fraction of the estimated 30,000 total genes in our genomes (Nature 409, 860−921; 2001; and Science 291, 1304−1351; 2001). We are genetically far more nuanced and variable than is reflected in just skin coloration. With more data, can we build a comprehensive understanding of ourselves, backed by societal strictures that encourage the beneficent use of the resulting knowledge rather than an urge to discriminate? Can we follow Aristotle's advice to "...venture on the study of every kind of animal without distaste; for each and all will reveal to us something natural and something beautiful. Absence of haphazard, and conduciveness of everything to an end, are to be found in Nature's works in the highest degree, and the resultant end of her generation and combinations is a form of the beautiful." (On the Parts of Animals, Oxford, 1911)?
Some of the essays that follow in this special issue conclude that "race" might be useful from a patient-centered viewpoint because of concerns about neglected populations and effective care, but most are extremely cautious about linking race to a genetic reality. "Genetic variation, classification and 'race'" by Lynn B Jorde & Stephen P Wooding is typical:
New genetic data has enabled scientists to re-examine the relationship between human genetic variation and 'race'. We review the results of genetic analyses that show that human genetic variation is geographically structured, in accord with historical patterns of gene flow and genetic drift. Analysis of many loci now yields reasonably accurate estimates of genetic similarity among individuals, rather than populations. Clustering of individuals is correlated with geographic origin or ancestry. These clusters are also correlated with some traditional concepts of race, but the correlations are imperfect because genetic variation tends to be distributed in a continuous, overlapping fashion among populations. Therefore, ancestry, or even race, may in some cases prove useful in the biomedical setting, but direct assessment of disease-related genetic variation will ultimately yield more accurate and beneficial information.
The scientific question of race is obviously not settled, and probably won't be in the near future -- mainly because the word is so damn shifty. My own take on race is that, even though it seems so chimerical from so many points of view, nonetheless it has a long history of linkage to (1) inequality and (2) corporeality that in fact make it more useful for describing how medieval groups conceptualized themselves and others than terms which are supposedly more neutral.