As for any attempt to reify Germans over Slavs, Englishmen over Irishmen, Nordics over Alpines and Mediterreneans, those are screamingly obviously on the “Idealist” or “thought” side of the equation. But they are falsified by the genomic components on the “empirical” or “experience” side.I assume GW's assertion reflects a misinterpretation of studies such as this one, which involve principal components analysis of European SNP genotype data. I understand GW to mean he somehow believes these studies indicate no two European populations differ genetically in any systematic way which could lend support to "intra-European supremacist" arguments. Naturally, GW is wrong.
Granting that "superior" and "inferior" are subjective judgments rather than scientific universals, essentially any demonstration of a population's genetic distinctiveness can be seen to support both preservationist and "supremacist" arguments. Studies (from Cavalli-Sforza's work on "classical" markers to the recent analyses of 500k+ SNP microarray datasets) have repeatedly demonstrated sub-European genetic distinctiveness (particularly along a N/S or NW/SE axis).
SNP/PCA studies can (and do) demonstrate distinctiveness. They can't (and haven't) proven the absence of intra-European differences in genes influencing IQ and personality, for example -- if for no other reason than that no one has so far been able to use SNP genotypes to explain much variation in phenotypes like IQ. (In addition, 2-dimensional PCA plots typically leave plenty of variation unaccounted for, so -- even if we limit ourselves to considering common SNP variants -- samples which have identical values on the first two PCs might turn out to vary in some important way.)
Even the largest commonly-used SNP microarrays capture only a small fraction of human genetic variation, and definitive answers on many issues will await complete sequencing of large numbers of genomes.
In the meantime:
Compared to southern Euros, NW Europeans are demonstrably "superior" at digesting lactose as adults (92% LP in Utah vs. 11% in S. Italy), and -- though this may shock GW -- have demonstrably higher frequencies of alleles associated with light pigmentation.
Recent and ongoing (and probably accelerating) human evolution is a reality. "Genomically", Southern Europeans are more similar to Ashkenazi Jews than to Northern Europeans. Strangely, AJs and SEs don't have identical average IQ scores and personalities, and one doubts the finding would lull a Jewish supremacist into calling for a merger between AJs and SEs. "Small" genetic differences may have large phenotypic effects.
Even if, say, the English and Sicilians sprang from identical pools of ancestors 15,000 or 10,000 or even 5,000 years ago (and the genetic evidence says this was not the case), there's been plenty of time for differences to accumulate and plenty of reason to believe they have. See, e.g., Gregory Clark (thanks TGGP for that particular link). I find it hard to imagine radical differences in culture between Eastern and Western Europe (or, to a lesser extent, between England and Ireland) haven't engendered (and/or been engendered by) some degree of genetic differentiation. Again, even if you could show large German and Polish samples plot identically on a 2-d PCA chart (they don't), you would not have demonstrated genetic identity between them.