consistency of results could embolden us to pursue more research using essentialist-style methodology. The procedures here described are not properly tests of character-based essentialism itself but rather tests of specific character weightings derived from an essentialist approach. Here, I evaluate character-based essentialism in three ways using seven different character weightings. First, I constructed a list of skeletal characteristics associated with bipedalism in extant humans and scored their presence or absence in Au. africanus and the Little Foot skeleton (Au. africanus sensu lato or Au. prometheus), two taxa that all creationists agree are not human and should not exhibit human-specific characteristics. Second, I use a larger list of craniodental characteristics to identify putatively essential characteristics for six different samples of taxa. I then use these characteristics to test for consistency and success in distinguishing human from nonhuman, based on cases that all creationists agree on. Finally, I use the same subsets of characteristics in distance-based clustering. Again, I look for consistency among the character samples as well as consistency with previous evaluations of the human kind in order to assess the utility of a character-based essentialist approach to identifying the human kind. METHODS As an initial test of essentialism, I compiled a list of fifteen skeletal characters associated with bipedalism in human beings (Table 1), based on the published literature and personal examination of skeletal casts of a human, a chimpanzee, and a gorilla. The human skeleton cast is in the collection of Core Academy of Science, and access to the chimpanzee and gorilla skeletons was provided by Southern Adventist University. Each character was coded such that the presence of the character is consistent with bipedalism. Using photographs, 3D scans, and published descriptions, I scored each of these characters for their presence in Australopithecus africanus and in the Little Foot skeleton, taxa that all creationists accept as nonhuman. For a second test, I used a previously published set of 391 craniodental characters scored for 24 hominid taxa (Wood 2020). The taxa include eleven members of Homo, five Australopithecus, three Paranthropus, Ardipithecus, Sahelanthropus, Kenyanthropus, and the outgroups gorilla and chimpanzee. Homo erectus is treated separately as African and Asian forms, and the Dmanisi fossils are included as a single taxon, Georgian H. erectus. I used the recoded characters such that the character state zero always codes an absent character state. Using these characters, I defined six subsets. The first subset consists of characters where the state in Homo sapiens is different from the state in chimpanzee and the state in gorilla. I call these the sapiens only (SO) characters. The second subset consists of characters found in extant apes only (EAO), where the character state in chimpanzee is the same as gorilla but different from H. sapiens. The third subset expands the set of apes to include Au. afarensis and Au. africanus, such that all four ape taxa have the same state that differs from the state seen in H. sapiens. I call these the four ape (FA) characters. For the fourth subset, I define a “Lubenow Core” (LC) set of humans to include H. sapiens, Neandertals, and African and Asian H. erectus. This subset corresponds to the taxa that Marvin Lubenow accepted as human in his book Bones of Contention (Lubenow 2004). The LC characters have the same state in all four human taxa and differ from the state in gorilla and chimpanzee. I created two additional character subsets to act as controls. First, I selected characters that were the same in all three Paranthropus species but different in Homo sapiens. These Paranthropus-only (PO) characters provide an alternative ape group by which to evaluate a different set of putatively essential characteristics. For the second control set, I selected characters that differed between Homo sapiens and Neandertals (HN characters), as a test of characteristics that would be unique to modern Homo sapiens. For all of these character subsets, polymorphic characters were not included in the putatively essential character subset. Since essentialism requires that all members of the same taxon have the same character state, polymorphisms by definition cannot be essential. For each subset, I recorded how many of the characters agreed with the human (LC, SO, HN) or ape (EAO, FA, PO) characters for all remaining taxa. The raw number of character differences were then converted to percent differences to generate a simple matching distance. With this distance I then created a unidimensional scale that included all taxa. For the LC, SO, and HN characters, a distance of zero corresponded to the human taxa or taxon, and a distance of one corresponded to the apes (LC or SO) or Neandertal (HN). For the remaining taxa the distances from the human taxa placed each taxon at a specific location on the scale. Gaps between adjacent taxa on this scale could then be calculated. This procedure was then repeated for the EAO, FA, and PA characters, where zero distance corresponded to the ape taxa and the distance of one corresponded to the human taxa. Statistical significance of the gap sizes between adjacent taxa was then estimated from simulations. Random positions from zero to 1. Anterior position of the foramen magnum 2. Lumbar lordosis or lumbar vertebral wedging 3. Bowl shaped pelvis or iliac flaring 4. Bicondylar angle >4° 5. Proximal articular surface of tibia in line with tibial shaft 6. Articulation of medial cuneiform and first metatarsal flat and inflexible 7. Distal articular surface of first metatarsal rounded in medial view and extended superomedially over metatarsal shaft 8. Adducted hallux 9. Superior surface of second metatarsal flat and not convex 10. Medial and lateral condyles of distal femur same size 11. Deep patellar groove of distal femur 12. Tibia-talar joint relatively perpendicular to tibial shaft 13. Superior surface of proximal pedal phalanges flat and not convex 14. Fifth metatarsals exhibit lateral torsion 15. Semicircular canal shape human-like (most simlar to extant humans as judged by shape coordinate PCA) Table 1. Characteristics associated with bipedalism in living human beings (Homo sapiens). WOOD Essentialism and Human Kind 2023 ICC 90
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