Dobzhansky on Weidenreich's species concept21 May 2007
I found this passage in the discussion following T. Dale Stewart's paper, "The problem of the earliest claimed representatives of Homo sapiens," from the 1950 Cold Spring Harbor Symposium on Early Man.
DOBZHANSKY: The great variability of the Neanderthaloids, so ably described by Drs. McCown and Stewart [McCown's paper immediately preceded the one under discussion], bears upon one of the basic problems of human descent. It is now clear that the Neanderthaloids and the so-called sapiens type were at no time two reproductively isolated species, but rather component races of a single species. Some modern populations may carry genes that were present in the Neanderthaloids, and other moderns may not carry such genes. But this does not mean, of course, that mankind consists of races descended from Neanderthaloids and other races which came from the sapiens type contemporaneous with the Nenderthaoids. In general, the old anthropological alternative of monogenic versus polygenic descent of man ceased to exist when considered from the vantage point of the present evolution theory. Different populations (races) of a polytypic species may be descended largely from different races of the ancestral species and may differ in some genes in which these ancestral races differed. And yet, a polytypic species may still evolve as a single genetic system. Favorable mutants or gene combinations arrived at in one part (race) of such a species may, under the influence of natural selection, eventually spread to all other parts and thus become a common property of the entire species. Thus, local autonomy of the gene pools of racial populations does not preclude retention of a basic unity of the species as a whole. I would like to point out that this view agrees quite well with the conclusions reached by the late Weidenreich on basis of purely morphological analysis of pre-human populations. This is worth while [sic] stressing because Dr. Weidenreich has sometimes used expressions which seemed to put him close to the old-fashioned polygenist camp, which he actually rejected absolutely (Dobzhansky, following Stewart 1950:106-107).
I love these discussions, which often included exactly the people whose opinions you would like to see, and sometimes some surprising ones. For instance, after Dobzhansky in this particular discussion, Joseph Birdsell and Stewart had an exchange about the implications of the fluorine dating of Piltdown for interpreting variability within modern humans (Birdsell's point being that such an apelike jaw must extend the variability of Homo sapiens even further if it is actually recent! Ha!)
And they often jumped off on tangents, like the Piltdown tangent, which remind you of the other things that people cared about besides the immediate topic. I think it's the closest thing to science blogging that the 1940's and 1950's had to offer!
Stewart TD. 1950. The problem of the earliest claimed representatives of Homo sapiens. Cold Spring Harbor Symp Quant Biol 15:97-107, comments following.