In my previous post, I documented how it was not “out of context” to quote the paper Hawks et al. (2000) stating that the paleoanthropology evidence shows a sudden or non-gradual origin of humanity. I noted that in 2024, the paper’s lead author, John Hawks, wrote a response to the use of his paper. He claims that when his paper is making these statements about the sudden and abrupt appearance of Homo, they are speaking hypothetically, asking “what if the first appearance of H. erectus was a rapid event? What would that look like?” (Emphasis added.)
When Hawks adds the word “if” he writes as if he’s offering a hypothetical thought experiment about what things might look like “if” Homo erectus arose rapidly. But in fact, Hawks is plainly covering his tracks and really not fairly representing his own paper. There is no conditional “if” in the discussion we just saw. Hawks and his coauthors give a straightforward interpretation of what the fossil evidence shows.
If you don’t believe me, consider the perspective of the widely reputed AI chatbot Grok. I uploaded a PDF of Hawks et al. (2000) to Grok and asked it, “Does this paper interpret the fossil record to show that Homo sapiens arose suddenly and abruptly?” Here’s what it said back:
Yes.
The paper explicitly interprets the fossil (paleoanthropological) record as evidence of a sudden, abrupt origin of early Homo sapiens (their term for the species that includes what others often call Homo erectus/H. ergaster, the direct ancestor of later humans) at ~2 million years ago. This is framed as a cladogenetic speciation event involving a population bottleneck and “genetic revolution,” not gradual anagenic change.
Key statements and reasoning from the paper (pages 3–6, with supporting figures):
“A hominid speciation is documented with paleoanthropological data at about 2 MYA by significant and simultaneous changes in cranial capacity and both cranial and postcranial characters.”
Early H. sapiens was “significantly and dramatically different from earlier and penecontemporary australopithecines in virtually every element of its skeleton … and every remnant of its behavior.” The authors describe this as “a real acceleration of evolutionary change from the more slowly changing pace of australopithecine evolution.”
Four “interrelated complexes of changes” (brain size and shape, dental function/face, cranial buttressing, and dramatic body-size/proportion increase) occurred “all together, at the time of its origin.”
“The anatomy of the earliest H. sapiens sample indicates significant modifications of the ancestral genome and is not simply an extension of evolutionary trends in an earlier australopithecine lineage.” Its combination of features “never appears earlier; some of its characteristics are unique.”
“The changes are sudden and interrelated and reflect a bottleneck … no gradual series of changes in earlier australopithecine populations clearly leads to the new species, and no australopithecine species is obviously transitional.” (They reject habilines as transitional forms because the known specimens are too young.)
“In sum, the earliest H. sapiens remains differ significantly from australopithecines in both size and anatomical details. Insofar as we can tell, the changes were sudden and not gradual.”
The paper contrasts this abrupt shift with the much slower, smaller-scale changes between earlier australopithecine species (e.g., cranial capacity increasing only ~25 cm³ from A. afarensis to A. africanus, versus a jump to ~860 cm³ in early H. sapiens). It uses the fossil evidence (e.g., KNM-ER 2598 occiput, KNM-ER 3228 innominate, femur-length distributions showing a distinct large-bodied mode) to argue that the anatomical and behavioral package appeared rapidly, supporting a founder-effect bottleneck rather than gradual evolution.
This interpretation underpins the paper’s central claim: an early (~2 MYA) population-size bottleneck at the origin of the H. sapiens lineage is compatible with both the fossil/archaeological record and the genetic data (long-term low effective population size), while recent bottlenecks are ruled out.
All of that sounds remarkably like what I wrote in my previous posted. So unless Grok is experiencing some radical hallucinations, I think Hawks is not giving us an entirely objective analysis of his own paper.
What Does Hawks Believe Today?
We’ve just established that the prior quotation of Hawks et al. (2000) does not take anything “out of context.” That paper clearly interprets the fossil record as showing the “abrupt” and “sudden” appearance of Homo erectus. In his 2024 response, Hawks now claims that “A lot has changed in the fossil record during the last 24 years” and he cites the discovery of Australopithecus sediba in 2010 which has some traits that are similar to Homo erectus. He claims that today, “Australopithecus and their close relatives were much more humanlike, and Homo erectus much more Australopithecus-like, than it once seemed.”
All that’s fair — people are always welcome to change their views in response to what they feel is convincing new evidence. But this raises the question: Professor Hawks’s prior paper said “no australopithecine species is obviously transitional,” so I’m wondering exactly which australopithecine was directly ancestral to Homo? His post doesn’t say. He makes a big deal about Australopithecus sediba, but as I’ve discussed before, this species post-dates the first evidence of Homo and one paper found that based upon the chronology of the fossil record, the likelihood that this species could be ancestral to Homo is “less than 0.001.” Even a 2016 paper that ultimately argues that the distance between Homo and Australopithecus is small — published years after the discovery of Australopithecus sediba — nonetheless acknowledges that “the fossil record bearing on the origin and earliest evolution of Homo is virtually undocumented” and that “The fossil record bearing on the ancestry of Pleistocene Homo is poor.”
We’re left with a curious situation where Hawks et al. (2000) plainly acknowledges the abrupt appearance of Homo in the fossil record, and quoting it as such doesn’t take the paper “out of context” as Hawks charges. (At least according to Grok, I quoted the paper fairly!) So Hawks and others have clearly acknowledged the abrupt appearance of Homo in the past. But in trying to deflect those who cite them, Hawks has quite strangely misrepresented what they wrote. Again, as Grok noted:
The paper explicitly interprets the fossil (paleoanthropological) record as evidence of a sudden, abrupt origin of early Homo sapiens (their term for the species that includes what others often call Homo erectus/H. ergaster, the direct ancestor of later humans) at ~2 million years ago.
Hawks may have changed his views since that time, and today he believes the evolution of Homo was more gradual. Fair enough. He has the right to believe whatever he wishes! But the evidence he’s citing doesn’t seem to solve the problem. What exactly was it that wasn’t Homo that evolved into Homo? Nobody can seem to answer this question — not even Grok:
