Monday, May 16, 2016

Let's talk about Homo naledi

It was a huge relief to launch Human Genesis and release the special issue of JCTSB!  I had been working on those projects since the day the Homo naledi papers were announced, and it was a lot more work than I expected (always is).  But I'm very happy with all of it.  Now at last I can start talking about Homo naledi, and that might be the biggest relief of all.

For those of you keeping score, here's where creationists stand on Homo naledi:

  • AIG's Mitchell and Menton think it's "most likely an ape," presumably based on how different it is from us (and other fossil forms that they also accept as human).
  • ICR's Clarey thinks the bones are a combination of human and non-human bones.  He wrote, "The scientists built an imaginary creature from bones that likely come from both humans and non-humans."
  • CMI's Peter Line took substantially longer to come to a conclusion than ICR or AIG, and he argued that it was probably a pathological form of human.
  • GRI's Ronny Nalin wrote that we don't know what Homo naledi was, although he did say it was likely post-Flood.  Like Line, he also took a bit longer than AIG and ICR to write up his thoughts.
  • W+W's Michael Brandt posted a very detailed discussion of H. naledi and argued that the remains should probably be placed in a completely new genus (not Homo or Australopithecus).  Consequently, he also claimed that H. naledi is not human.

So we've got nearly the entire array of opinions on this one.  You might recall the hubbub over A. sediba back in 2010, when I was the lone holdout against the unanimity of creationists claiming it was not human.  This time, things are considerably different, and that's kind of a relief.

In case you didn't get a chance to read the JCTSB articles, here's how things came out:

  • My baraminology study used characters published in the supplemental appendices to Berger's paper.  I found that Homo naledi unquestionably clustered with the cluster that contained Homo sapiens, which in my assessment makes it part of the "human" cluster (that is, descended from Adam and Eve).  I also found that A. sediba continues to cluster with the human cluster, and by using a set of characteristics from a different study, I found that the Dmanisi hominins are also part of the human cluster.  As before, I continued to find a discontinuity between humans and nonhumans in all of my analyses, which I take as confirmation of the creationist claim that there is a difference between human and nonhuman.  I think this study is a pretty big deal, since once again we find that purported intermediates do not collapse the separate human and nonhuman clusters into a single cluster.
  • To my surprise, O'Micks also submitted a baraminology study of Homo naledi that re-coded measurements from Berger's paper.  That was a different source of information than what I used, but the result was consistent: Homo naledi grouped with the human cluster, and there was a difference between the human cluster and other clusters of nonhumans.
  • Kurt Wise's assessment of the fossils basically reviewed and affirmed the conclusions of Dirks's paper.  Homo naledi was intentionally buried in a dark cave, and it would have required the use of torches or some other light source for the individuals to get the bodies back that far.  He argued that these attributes indicated that Homo naledi was most likely human.

Now you might be thinking that these three evaluations aren't really independent, that I went around and recruited only people who agreed with me to publish in this special JCTSB issue.  While it is true that I wanted to present a unified position in this special issue, the three technical studies all present different aspects of the discovery, and the O'Micks study really was independent, since I didn't even know it was coming.

So what does all of this mean?  It means that Homo naledi is weird.  I do happen to think there is more than enough evidence from the burial alone to argue that it was human, but I can also understand why there would be disagreement.  The body form of Homo naledi really is different from modern humans and Neandertals, and that is often judged to be a big deal by lots of creationists.

What surprises me is how hostile everyone seems to be towards the evidence for burial.  I understand why noncreationists would be skeptical: This "animal" has a brain the size of an orange.  Berger's research team are quick to point out that they aren't saying this is a ritual burial in the same way that Homo sapiens adorns their dead for burial.  They just call it "intentional body disposal," or as Lee Berger said at AAPA2016, "It's a ritual only in the sense that they keep doing the same thing [i.e., disposing bodies in the same location]" (that's a rough paraphrase).  I suppose for creationists who agree that Homo naledi was not human, even body disposal is too much to accept, but the evidence for intentional burial seems quite impressive at this time.

But this post is already too long, so I'll discuss a bit more about that next time.

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