A Tradition of Argument

When I survey the literature on paedomorphosis in human evolution, I cannot help but recall such catch phrases as "the dead hand of the past"—for Bolk's explanation and the rejected evolutionary theory hidden within it established a strong tradition of argument. This tradition, in subtle ways, still hinders the application of new and more fruitful approaches. Since Bolk insisted on a harmonious retardation of all "essential" features, the experimentum crucis has been cast in the following way: enumerate as many morphological features as you can and judge which are paedomorphic and which are not. If you regard a vast majority, or perhaps merely a "basic" list, as paedomorphic, you accept the hypothesis; if you disagree with this claim, you reject the hypothesis.

Thus, Weidenreich (1932) based his rejection on the fact that several adult features are closer to their fetal condition in Peking Man than in modern Homo sapiens. Since "Sinanthropus" is our direct ancestor, Weidenreich argues, the last stages of human evolution cannot have evolved by a general retardation in development. Ewer's rejection is squarely in the enumerative tradition: "The paedomorphic characters although undoubtedly a necessary element in the 'ascent of man' are secondary consequences of the nonpaedomorphic key characters" (1960, p. 180). And Delsol and Tintant (in press) write: "The several paedomorphic characters which incontestably accompany the appearance of man represent only a quite secondary element of the traits that mark this evolution. The principal elements of the phenomenon correspond to divergences."

Supporters of paedomorphosis scrutinize the same lists of features but apply different weights. Schindewolf classed as paedomorphic "the typical characters of the human skull—i.e. the characters that make up the essence of the human skull and that distinguish it so fundamentally from that of the lower mammals" (1929, p. 762). Konrad Lorenz argues: "The number of persistent juvenile characters in human beings is so large, and they are so decisive for his overall habitus, that I can see no cogent reason for regarding the general juvenescence of man as anything other than a special case of true neoteny" (1971, p. 180).

I believe that this enumerative tradition is the worst way to carry on the discussion. Modern evolutionary theory has driven Bolk's notion of harmonious development into obsolescence: to invoke it now as a criterion for judgment is to set up a straw man of surpassing weakness. No Darwinian supporter of retardation as a major element in human evolution can deny that many distinctive features are not