328 | Mary Roach on Replacing Parts of Our Bodies

Hello, everyone, and welcome to the Mindscape podcast. I'm your host, Sean Carroll. A few weeks ago, as I'm recording this, there was some kind of global summit. I'm fuzzy on the details. I didn't really do a lot of research for this intro. But the point is that there was a conversation between Vladimir Putin, who's the president of Russia, and Xi Jinping, who's the leader of China, that was caught on what seems to be a hot mic. In other words, the microphone was turned on, but the speakers didn't actually know that they were being recorded or broadcast, and so they were more candid than they would otherwise be. You might think that they'd be talking about global geopolitics or trade agreements or something like that or even political philosophy, but no. Putin and Xi were talking about bioengineering and the possibility of immortality or at least longevity, ultra longevity. They were saying how advances in biological science were making it possible to replace organs. And if you could go at this rate, you might end up living for a hundred and fifty years or even more. Subtext being that they would like to live for a hundred and fifty years or even more. And, of course, that's a little contestable, that claim. I mean, there's no contestation to the fact that bioengineering and biology more generally are absolutely leaping ahead by leaps and bounds. We're learning a lot, but there's no actual breakthrough that so far has dramatically increased the upper limit on human lifespans. In fact, this is an issue more generally with sort of the techno optimist way of thinking about the world. And I say this as someone who is very much attracted to the techno optimist way of thinking about the world, and to someone who does understand the difference between something being literally incompatible with the laws of physics, in which case you should just give up on it, versus something just being really, really hard, an engineering problem as we call it. And many biological things are sort of engineering problems. But it's too easy to imagine taking biological things and just making them arbitrarily better. That turns out to be really hard. It's not that it can't be done. We do it. We're getting better at it. But biology is very, very, very complex compared to physics, mechanical engineering, even chemistry, things like that. So today's guest, Mary Roach, is one of our leading and also most entertaining science writers that we have. She's the author of books like Fuzz and Stiff and Bonk and Gulp, as well as Packing for Mars. And her new book is called Replaceable You Adventures in Human Anatomy. And Mary doesn't have, you know, an overarching lesson that she's trying to teach us here, but she goes through a large number of examples, both historically and in contemporary science, of how we replace our limbs and our organs and our skin and our …