David Reich: belief

Transcript context

…One thing I would love to see—I assume this will change over time as more data comes up—is some sort of chart that is superimposed upon a world map and evolves over time. Maybe you can have blobs representing different population groups. You can start off with the archaic humans and go back like, 200,000 years ago, even before that because this is a global event. It's not just an African event. For hundreds of thousands of years, you can just see different populations splitting off, merging back together. If somebody could make that sort of animation, that would be very useful. I think you can. People have tried to make animations like this in some ways. But one way to think about it is that there's a huge danger in being too interested in yourself. This comes across in my book. It's very tempting to be interested in your own history and think it's important. It's obviously not important compared to other people's history. However, if you think about one person's history and about where their ancestors lived two to eight generations back in the past, those are your great-grandparents and great-great-grandparents and you may even know where they live. Then you can actually just plot on a map a different number of generations back in the past where your ancestors lived. It's interesting to do within your family. My ancestors going back a few generations are in different parts of Europe, for example. People do this and when you get a test back from one of these personal ancestry testing companies like 23andMe, they'll say, “Oh, you are 20% Irish and 30% Chinese” or whatever it is and so on. What they're referring to is if you roll back 20 or 30 generations, where your ancestors are scattered in proportions. But then if you roll back 3000 generations, there's some in East Africa and some Neanderthals, right? For any one group of people or any one person, there's different time slices that matter. 30 generations ago, you get the 23andMe output. 3000 generations ago, you get the proportion of your ancestors who are Neanderthals or not Neanderthals or Denisovans or something like that. If you're from one of the many populations around the world that live in Denisovans. If you are any population going back further in time, presumably there's something similar happening. Mostly in Africa, but possibly outside of Africa 300,000 years ago, people's ancestors will be coming from different places. It's very plausible that people's ancestors are not all in Ethiopia 200,000 years ago. In fact some of them are maybe in North Africa. Some of them are maybe in West Africa. Some of them are in South Africa. Some of them are in Eurasia. Actually appreciable fractions are in each place. That braid and that trellis is coming together again and again over time. As you move further back, they'll collapse. Some will go extinct, some will reappear, some will re-merge. At any one point, there's never a singularity. I don't know if you're familiar with Nat Friedman's Vesuvius Challenge. I don't know if you saw that when it was going around. It’s the scrolls in the library at Herculaneum. There's a volcano during the Roman empire, 79 AD. It buried the scrolls in that library. They all became literal ash, or at least very burnt. Nat Friedman found this professor who had done CT scans of these scrolls. There was really no way to decipher them. We just had the CT scans. It felt like the kind of thing where somebody out there might be able to figure out a technique for how to do it. We know what the end results should look like. We just don't know what the intermediate steps look like. It feels plausible with modern technology. So they offered a million dollar prize and a 21 year old with a GPU coded up a CNN model to decipher these scrolls. Is there something in your field which has this sort of feeling? There's something we need to figure out? We don't know the exact right technique. But if you could put it out and offer a million dollar bounty for it, maybe somebody will come up with a cool new technique to figure it out.…

Stored transcript either side of the excerpt. The highlighted words are the published quote; the surrounding text is unedited source, never generated.