ヒトのネオテニー説批判

The purpose of this paper is to indicate a biological misunderstanding on the neoteny doctrine and a danger of the biological determinism inevitably included in the doctrine. The neoteny doctrine discussed in this paper is used in a broad sense, including Bolk's fetalization, Montagu's neoteny and Gould's retardation theories. A general understanding of the term (concept) of neoteny is a mixture of the above-mentioned three, though exemplifications of their characters for neoteny are not always same. Morphogenesis is classified into the following eight types by de Beer; 1) caenogenesis, 2) deviation, 3) neoteny, 4) reduction, 5) adult variation, 6) retardation, 7) hypermorphosis, and 8) acceleration. According to this classification, Bolk's fetalization and Montagu's neoteny correspond to neoteny, and Gould's retardation is to retardation and neoteny. Anatomical characters of Homo sapiens are enumerated in Table 1, where characters identified as neoteny by Bolk, Montagu and Gould are marked with circles. However, the critique of the neoteny doctrine should be focused on the anatomical characters for bipedal walk in erect posture, since this posture is the most important biological character of Homo sapiens. Bipedal walk in erect posture consists of erect posture, bipedalism and walk. The most fundamental characters are sigmoidal flexure of a vertebral column for erect posture, shape of a pelvis for bipedalism, and plantar arches for walk. If the neoteny doctrine is correct, those fundamental characters of Homo sapiens should appear in fetus or infant stages of anthropoids. Anatomical and comparative embryological examinations reveal that those characters are not observed in these stages. It is, therefore, concluded that the above-mentioned characters of Homo sapiens do not support the neoteny doctrine. Since the fundamental characters of Homo sapiens do not support neoteny, discussion on the other characters hitherto related to neoteny seems to be unnecessary. However, we discussed such characters as cranium, cranial flexure and direction of vagina so far regarded to be representative for neoteny, and proved that these characters are not to be neoteny. All of those who support the neoteny doctrine of Homo sapiens believe the human body as a perfect (harmonic) reality without any contradiction and are, at the same time, lacking in historical (geohistorical or phylogenic) viewpoints to human body constituent organs. Moreover, the neoteny doctrine originates in neglect or disregard of the importance of 'human society' in the course of humanization of the genus Homo. Lastly, we discussed the background for the birth of the neoteny doctrine and suggested the existence of biological determinism behind. We insist that organically unified natural and social sciences could become only the science in the 21 century.