in 1884, and was soon appointed lecturer with the chair of Anatomy at the University of Amsterdam in 1886. He was neither an anthropologist nor a paleontologist, but he did intend to devote his free time to researching this Pithecanthropus. In 1887, he decided to leave Amsterdam to settle in Sumatra with his family, and joined the Royal Dutch Indian Army as a doctor.
Human paleontology was not yet a discipline; the Neanderthal skeleton and the Gibraltar skull had still not been described. Dubois went to the island of Java and prospected the ancient formations of a river, the Solo, on a paleontological site called Trinil. Between 1891 and 1892 many fossils were collected with the help of two engineers and some convicts. These fossils included two human molars and a human-like skull cap with a low vault and a strong bulge above the orbits. Subsequently, a perfectly preserved femur of modern appearance was collected about 15 m from the area. The skull base was missing and only the proximity justified the association of the femur and the skull cap. Dating went back to the Middle Pleistocene (500,000 years in 2020). Dubois published a description of the fossils in Java in 1894 (Dubois 1894), comparing the skull cap with a chimpanzee and decided to attribute the fossil to an extinct genus of Hominids, the Pithecanthropus, and to add the femur to define the species as erectus, in other words, the erect ape-man. Cranial capacity was estimated at 900 ml, while that of Homo sapiens is 1,350 ml on average, that of the orangutan is 320–340 ml and that of the gibbon is 82 ml (White 2007). On the strength of his discovery, Dubois traveled around Europe in 1895 to obtain the approval of anatomists. The monograph was read carefully by the most informed authorities, some 20 experts, and the conclusions were more in the realm of opinions, ranging from a giant gibbon to an extinct genus of intermediate hominin between Ape and Man. The Société d’Anthropologie de Paris appreciated the discovery and its implications. In January 1895, Léonce Manouvrier (1850–1927), a specialist in the physiology and anatomy of the human brain, presented his analysis and conclusions (Manouvrier 1895). After seeing the originals, he confirmed his position in 1896 and invited Eugène Dubois to come and present his arguments (Manouvrier 1896). The numerous fossils of vertebrates resembled the most recent species of Siwaliks (2 million to more than 700,000 years old).
If the skull cap was that of a hominin, then the date when Man’s ancestors must have appeared would defy theologians. However, the association of the “modern” femur with a skull and a brain both different from that of a Homo sapiens posed a problem. The discussion revolved around bipedalism, within the framework of the doctrine of the locomotor origins of human anatomy. Indeed, for Dubois, who apparently did not compare the femur of a man with that of a gibbon, the latter was also bipedal:
Certainly it was not to be assumed that the femur of an anthropoid becoming bipedal could be very different from a human femur, the function being the same and the form already approximated by the origin. (Dubois, Le Pithecanthropus erectus et l’origine de l’homme, 1896, author’s translation)
Dubois was of course interested in the brain. In 1897, he published a synthesis on the evolution of the central nervous system, which was taken up and translated by Léonce Manouvrier for the Société d’Anthropologie de Paris:
The central nervous system of animals has increased in complexity and volume as their relationships with the external world have multiplied [...]. Mammals have much larger and more sophisticated brains than all other animals and show to some extent, according to the degree of the order to which they belong, an increasing development. They have acquired this superior organization gradually. Marsh1 and others have shown that the brain dimensions in mammals of the Eocene period are generally smaller than in related forms of the Neo-Tertiary or present day. Placental mammals of all orders in the earliest Eocene terrain have extremely small cranial cavities. In animals belonging to one of these orders, the brain was thinner than the spinal cord, so much so that it could have easily been extracted from the skull through the foramen magnum and the vertebral canal. At the same time, Marsh demonstrates that it was mainly the upper organized parts of the brain, the cerebral hemispheres, which were very poorly developed in these oldest placental mammals, with the result that these forms are even less distant, with regards to this point, from reptiles than recent placental mammals. This progressive development of the brain, in organization and volume, in vertebrates and mainly in mammals, as well as the remarkable volume and complexity in structure that it finally reaches in man, demonstrate that in this organ, the development of function determines the complication of structure and quantity as well. (Dubois, Sur le rapport du poids de l’encéphale avec la grandeur du corps chez les mammifères, 1897, author’s translation)
The complexification of the mammalian encephalon was maintained during the Tertiary era and Man was therefore the last degree of complexity:
No animal of the same size has a brain size comparable to that of man. Anthropoid great apes, whose body weight is equal to that of man, do not even reach 1/3, and dogs with the same weight 1/10, with regard to the brain and the weight of a man. Only the elephant, the largest whales and the Rhytine (Rhytina stelleri)2, an animal that disappeared in the last century, outweigh man in terms of the absolute weight of the brain [...]. For animals whose body weight is minimal: the relative weight of the shrew’s brain is 1/23, the monkey lion 1/26, the Javanese Tupaja 1/41, the mustached bat (Vesperttlio mystacinus) 1/42, while the relative weight of the human brain is 1/46 to 1/45: however, among these, in the shrew and the bat, the brain has a much lower organization. (ibid., author’s translation)
Encephalization was therefore not a question of absolute mass, volume, or weight relative to the body, it was a question of organization and the duration of growth:
Not enough attention is paid to the fact that the brain increases less in weight with age than the rest of the body. In humans it has already reached about the same weight as in adults by the ninth year of life, while the body weight increases more than twice as much. The same can be seen, as Dr. Weber demonstrated, in all mammals; the brain has finished growing much earlier than other parts of the body. (ibid., author’s translation)
Eugène Dubois did not accept criticism and did not allow access to the fossils before 1923. He was nevertheless supported by Léonce Manouvrier, not on an anatomical basis as there was a lack of comparative material, but on the significant mineralization and the proximity of other bones. Following that, the Java collections were enriched and supported the case for attributing the skull cap, and molars, to at least one extinct genus of hominin. The femur fragments collected confirmed a different anatomy from Homo sapiens. The recognition of Pithecanthropus by the Société d’Anthropologie de Paris and the discovery of a new 30,000-year-old Homo sapiens skeleton, buried with evidence of artistic activity dedicated to the dead, were beginning to arouse curiosity. Man’s technical intelligence was fascinating, as demonstrated at the 1889 Universal Exhibition with Gustave Eiffel’s tower, and the imagination fed by his progress during the Industrial Revolution was not to be outdone by Jules Vernes’ imagined voyages to the moon and the deep sea.
1.2.2. Human paleontology and secularism
Then, a grave discovered in the depths of a cave revealed the mastery of symbolic language to express immaterial concerns. Spirituality emerged from a process of evolution that singularized the human phylum. The most visionary, and therefore the most realistic, understood the issues facing researchers engaged in the study of this process, the emergence of spirituality and the sense of ethics. Consistency is paramount; the brain cell structure is not in itself aware of being a structure with molecules, ions. Natural cell death is one thing, but Man had been able to distinguish between death inflicted on a hunted animal and natural death, developing a sense of the sacred and sacrilege. Ernest Haeckel’s anthropogeny was based on a racial scale and served to elaborate projects of societies structured on the principle of reproduction between those better adapted, or more efficient. Albert Gaudry had foreseen the threat of Haeckelian Darwinian monogenism. His anthropogeny prepared the breeding ground for a 20th century that would put them into practice by going as far as the programed elimination
