 Good morning, Hank, it's Tuesday. I recently got to wondering when the median human being was born, and in researching that question, I learned something interesting and surprising. But let's start with that hypothetical median person. So obviously, we don't have, like, super firm statistics on how many people have ever lived, or when they died, or any of that, but through a mix of population modeling and genetic research, our best current guess is that about 117 billion modern humans, as we are known, have ever lived. So I was trying to figure out, when did the person in the middle of that 117 billion live? The, uh, I'm bad at math, 58.5 billionth person. Now, I'd probably go to guess, like, 1,900, 1,750, something like that, because there are way more humans than there used to be. I mean, fewer humans lived on Earth 6,000 years ago than currently live in Mexico City. 7% of the people who've ever lived are currently alive, so the median human can't be that far removed from us, right? Except no, that's wrong. At least according to the Population Reference Bureau, the 58.5 billionth person probably was born sometime between 10 and 100 C.E., so about 2,000 years ago. That is to say, of all the people who've been born, most were born and died before the Roman Emperor Nero or the Malian Emperor Mansa Musa. They lived and died before the idea of minutes and seconds, before guns, before the emergence of Christianity and Islam as global forces, and before potatoes or pineapples were in Afro-Eurasia. This median person almost certainly could not read or write. They probably did not believe in one God, and if they survived to adulthood, which they probably didn't, they were probably farmers and probably had many children, some of whom almost definitely died. Now, when I was young, I was taught that in the old days, the old days were never quite defined, life expectancy was 30, which I took to mean that the average adult died at 30, and that's not the case. At least in Sweden where we have relatively good data, if you lived to be 10 in the early 1800s, your life expectancy was around 46. And in 1841 England, if you lived to be 20, your life expectancy was around 60. It's just that overall life expectancy was brought down to below 30 because child mortality was so high. These days one sometimes hears that the only reason life expectancy has gone up is because child mortality has gone down, and that's also not the case. In 1865 Italy, even if you survived childbirth, your life expectancy was under 50, today it's well over 70. Like, it's worth remembering that 200 years ago, about a quarter of all humans died of tuberculosis, and most of them died under 40. Also, girls who survived childhood had a very high chance of dying in childbirth, in some communities over 10%. That said, child mortality was very, very high. Like, in 1800 about 30% of people born in France died before the age of 10, but it used to be even higher. Like, in Iron Age France, life expectancy wasn't 28 or 30, it was 10 or 12. Our best current guess is that when the median person was born 2,000 years ago, half of all people died before the age of 10. Child mortality was so high that birth rates were five times greater than they are now, but the overall population of humans barely increased. And this is why the median human was born 2,000 years ago, not because there were so many people back then, but because there were so many people who died young. Early death wasn't common, the way that dying at, say, 65 is now, it was the norm, the way dying at 80 is now. I mean, even last year, more people died before the age of 5 than died between 65 and 69. So it's likely that even today, most of the 110 billion humans who've died never saw the age of 20. We can't do anything about historical rates of premature death, of course, but we can choose to live in a world where fewer people die early. I know we can make that choice because we have made it before. That's what we're trying to do at pih.org slash Hank and John and through silly things like Pizzamas, which, by the way, raised over $130,000 toward better maternal and child healthcare in impoverished communities. Thank you, Hank. I'll see you on Friday.