Cut marks and stone tools
My last post elicited comments that some of the sites I included in my map were dubious or debatable. And you know what? That's true. What's more, the mere fact that stone tools and cut bones occur together does not by itself indicate that humans were once present there. We've known for a long time that other creatures can make tools that look kind of like Oldowan flake tools (like chimpanzees). In fact, I would expect that some early human traces would have a sort of dubious quality to them, where they just don't stand out enough from the background to be conclusively recognized.
As I went down the Google Scholar rabbit hole looking up papers on the sites from my last post, I stumbled onto the fascinating world of automatic identification of tool marks on bones. I've known about this new field for a while, but reading about some of the recent applications really grabbed my attention. The techniques are fairly straightforward. Researchers use bones and stone tools to make a bunch of cut marks, then they photograph or scan them. Those images then become a training set for a computer to learn how to recognize cut marks. With that finished, researchers can then feed the computer images of archaeological bone surface marks with the hope of identifying real stone tool cuts. Researchers claim these computer models are more accurate than human experts in identifying real cut marks. (This is exactly the sort of thing we do for eukaryotic gene identification.)
What's the big deal? Here, I want to bring in an idea that Kurt Wise has pointed out for years. In his book Faith Form and Time, he wrote, "Trace fossils are often found below the oldest body fossils. This is consistent with the idea that the traces were made by organisms trying to escape catastrophic conditions" (p. 204). (Here, "trace fossil" mostly refers to trackways or footprints.) He's constructing an argument for the Flood in that quote, but I think it also can apply after the Flood.
After Noah and crew disembArk, there's a period of fruitful multiplying wherein people do not die. For example, if you go by the Masoretic chronology, the first to die was Peleg, Noah's g-g-g-grandson, and he died about 440 years after the Flood. In the Septuagint chronology, Shem's the first to die at 502 years after the Flood. Those sound like long lifespans, but that's nothing when you consider the radiometric age. The oldest presumptively human fossils are more than 3 million years old, but if they died after the Flood (which their depositional context suggests they did), then they are possibly less than 4,000 years old. That's an average time compression of 750 radiometric years for every true year. Now we don't think that compression has been uniform, so it's actually much higher for really "old" stuff.
All that to say that things separated by 500,000 to 1,000,000 radiometric years around 3 million years ago could very well be separated by weeks or months, maybe a few years at most, in real time. Now think about what that means for the occurrence of stone tools. It's possible you could have some very disadvantaged people doing subsistence living after the Flood moving around and leaving stone tools here and there long before one of their group actually dies, but that could mean there might be half a million radiometric years separating the earliest stone tools from the remains of the people who made them. The supposed cultural progression from Oldowan flakes to bifacial handaxes and beyond could very well be a handful of people improving their knapping game by trial and error. Also, there was probably not a long period of cultural stasis in Homo erectus, because the timeframe of Homo erectus just wasn't that long. It's kind of mindblowing when you really sit down and think about how the creationist approach to human history changes so many things.
Now back to my machine learning and stone tools theme. Are there really stone tools and cut marks on bones older than two million years outside of Africa? Obviously I can't answer that definitively (because I wasn't there to watch those cut marks happen), but there is a very interesting article about cut marked bones from Uruguay that were conventionally dated to 30,000 years ago. They found eight bones that the computer classified as having cut marks, four of them with >90% confidence. As usual, I wish there were more, but it's still fascinating. This precedes the Clovis culture by some 20,000 years. How could there be human artifacts so long before actual human remains showed up? Because it wasn't that long.
(Photo: Stone tools from Gesher Benot Ya'aqov, National Library of Israel, CC BY-4.0)
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