one were selected from a uniform distribution corresponding to the number of taxa in each character subset minus the number of reference taxa used to define the character subset (17 for LC, 19 for FA, 20 for PO, 21 each for SO and EAO, and 22 for HN). Gap distances between adjacent points (including 0 and 1) were calculated, and the procedure was replicated one thousand times. The resulting gap distances conformed to a Weibull distribution, and the statistical significance of any gap size could then be estimated using the pweibull function in R. Each character subset was then subjected to standard cluster analysis using simple matching and Jaccard distances. Distance correlation, medoid partitioning, and fuzzy analysis were all calculated using BARCLAY (https://coresci.org/barclay). Any additional calculations were done in R. RESULTS Bipedalism characteristics. Fifteen skeletal characteristics associated with bipedalism were selected from empirical comparisons and the published literature (Table 1). Fossils referred to Au. africanus exhibited twelve of the fifteen characteristics, with one more probable based on the anatomy of the proximal first metatarsal (Table 2). Since Au. africanus fossils are frequently found disarticulated and therefore might represent more than one taxon (as argued by Clarke 2013), the fifteen bipedalism characters were also scored on the Little Foot skeleton, StW 573. Most of Little Foot was found articulated in a small area and hence represents a single skeleton (Clarke 2019). Little Foot exhibited nine of the bipedalism characters out of ten that could be diagnosed from photographs and published descriptions (Table 2). If bipedalism is an essential characteristic of human beings, these bipedalism characters fail to distinguish human from taxa that are decidedly not human. Craniodental characters. A published set of 391 craniodental characters were scored for 24 taxa. The overall completeness of the character matrix is 52.8%. Character relevance ranges from 8.3% to 100%. Taxic relevance ranges from 9.5% (Kenyanthropus) to 92.8% (African H. erectus). A simple majority of taxa (13) have more than 60% of their character states known. The incompleteness of the matrix therefore limits its utility for wide samples of putatively essential character states. For example, only ten characters are scored for all eleven members of genus Homo, and none of the character states are identical in all eleven taxa. With the smaller sample of five Australopithecus species, 28 characters are scored for all five members of the genus, with only nine characters (1, 21, 58, 78, 79, 244, 249, 262, and 266) exactly the same for all australopiths. These nine characters fail to meet the definition of essential characters, however, since all nine character states are shared by at least one member of genus Homo. Smaller samples of taxa will therefore be necessary to explore character states that meet the requirement of being shared by the ingroup but not shared by the outgroup. The first character set from a restricted taxon sample is the simplest and most intuitive: characters for which the states found in Homo sapiens differ from the states found in chimpanzee and gorilla (sapiens-only or SO characters). I found 104 SO characters (Table 3). The remaining 21 taxa shared between 81 (African H. erectus) and 4 (Homo antecessor) of these character states found in Homo sapiens (Table 4). Neandertals—a taxon widely accepted as fully human by creationists—exhibited only 60 of these character states out of the 69 that were known for Neandertals. In fact, none of the characters with known states for all taxa have a unique, autapomorphic state in Homo sapiens. Therefore, we find no characters that meet the requirement of essential characters for Homo sapiens only. By taking the number of character states that differ from theSO character states, we can calculate a simple matching distance that represents the percent difference between a taxon’s character states and the SO character states. These distances can be arranged on a linear scale, and we can examine that scale for any notable gaps that might indicate a discontinuity between human and nonhuman taxa. This procedure dispenses with the strict essentialist approach and treats Character Number Au. africanus StW 57 1. Present, STS 5 (Ahern 2005) Present (Clarke and Kuman 2019) 2. Present, STS 14 Not yet described 3. Present, STS 14 Present (based on photographs in Clarke 2019) 4. Present, STS 34 Present (Heaton et al. 2019) 5. Present, StW 514 Present (Heaton et al. 2019) 6. Present, StW 595 Present (McHenry and Jones 2006) 7. Present, StW 595 Unknown, distal surface damaged 8. Probable, StW595 Present (DeSilva et al. 2019) 9. Present, StW 89 Unknown, fossil not recovered 10. Present, TM 1513, STS 34 Absent (Heaton et al. 2019) 11. Present, TM 1513, STS 34 Present (Heaton et al. 2019) 12. Present, StW 363 Present (DeSilva et al. 2019) 13. Absent, StW 355 Unknown or not yet described 14. Present, StW 114/115 Unknown, distal end damaged 15. Absent (Beaudet et al. 2019) Present (Beaudet et al. 2019) Table 2. Character scoring and documentation of bipedalism characters in Au. africanus and StW 573 WOOD Essentialism and Human Kind 2023 ICC 91
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