The Evolution Of The Butthole

14:45Hannah Fry:And so it began to really fill a hole in an equation. And now there are people who spend their entire careers studying, analysing, trying to decipher what dark matter is. no one's ever found it. But I mean, there is sort of quite good evidence that something like that exists. But there is this rival theory that says, well, what if Einstein was just wrong? Like, what if, you know, we were talking about scales earlier, what if Einstein works at the scale of the solar system, but doesn't work at the scale of the galaxy? What if there is something else that's missing? So there are some other people who are working on this rival theory, which is called modified Newtonian dynamics, that says, you know, actually kick Einstein out the whole phrase of like, oh, what are you?

15:28Hannah Fry:Einstein's not going to work anymore because they're just going to disprove everything that he ever came up with. I mean, that's one really big fundamental thing that would be pretty devastating to the entire scientific community.

15:40Michael Stevens:But I hope that they can get past that devastation because that's the only way you make progress. I mean, how exciting of an idea. I've never heard of this before. Modified Newtonian dynamics. So the idea is that Einstein is once again, just an approximation that's not good for big stuff. It's good for medium-sized stuff. And then we've got the quantum realm on one side and the transgalactic world on the other. How interesting.

16:06Hannah Fry:Yeah, because we already know that Einstein isn't a complete picture, exactly as you described, right? It doesn't capture things down at the small scale. So who's to say there's not another big scale above it?

16:17Michael Stevens:I always assumed, look, we've got the top half figured out. It's the bottom half that we still need to marry to the big. and yet maybe we're still just eating the filling of the sandwich and we don't know what two slices of bread are doing where is the bread michael that's that's the question i mean there's

16:33Hannah Fry:other things like okay so at our scale we make and actually the scale of galaxies and solar systems we really make the assumption that time goes forwards only you can't like smash a glass in reverse right that's sort of this unwritten rule um but the thing is is that at the quantum realm I think that they're slightly less comfortable with that as a baseline assumption. I mean, why should that be? And that, I think, is one that would really tear everything apart. There's also all the constants, you know, like Planck's constant. Hey, I've heard of that before.

17:09Michael Stevens:I've said that before.

17:11Hannah Fry:There's other constants about, for example, the way that electrons orbit an atom and the sort of strength of those forces. So who's to say that those constants have been constant throughout the entire history of the universe, right? Maybe actually they're just, we're seeing one snapshot in time of the way that they look or one corner of the universe in which they look that way. All of these are fundamental assumptions that actually, you know, you still have to question, right? You can't just accept them as fact and move on. And I think that everything would fall apart there. But I think actually the reason why I wanted to go beyond just the universe on this is that I had one thought.

17:54Hannah Fry:There's this really brilliant piece in the Sunday Times that was about scientific publishing. And I think that this assumption that actually scientists rely on a lot is that the peer review process is great. The way that scientists publish papers means that we end up with facts. And sometimes that looks on slightly shaky ground. Right. I think that's been an assumption for a long time, that scientific papers have been through such a rigorous process of peer review, of other scientists checking the numbers, checking that they work. You can trust every single scientific paper. And I think that there are a few little cracks in that.

18:37Hannah Fry:There's quite a lot of duct tape down there as well. A lot of scientific retractions. because the system isn't necessarily built for true stuff to come to the top.

18:51Michael Stevens:New stuff, too, has a big barrier because, again, it's not God-reviewed. It's peer-reviewed. It's other people who have their own community expectations and paradigms that are shared. Here's the thing, right?

19:07Hannah Fry:If you're a scientist, of course, you're contributing to this great big body of knowledge. Of course, you're advancing human understanding of the universe. Of course you are. But you're also trying to get a job. You're also trying to get a research grant. And the thing is, is that to do the things that are fundamentally and understandably selfish, sometimes they run counter to the things that serve that wide range. you know you need to publish papers you need to like get a reputation you need to be noticed internationally you need to like have people cite your work and all of that is um you know you do best in that situation when you are like pumping out papers when you've got got amazing data when you're like coming up with incredible results and so there are basically incentives in the system for people to just like, you know, fudge a little bit around the corners, like just sort of like, maybe just tweak the data a tiny bit here and there, maybe publish the most interesting results that they're getting and not the boring ones.

20:15Hannah Fry:And I'm not talking about necessarily direct manipulative behavior always here. I think sometimes it's sort of overlooking, there's like confirmation bias, all of that kind of stuff. And the thing about the peer review system is that you're handing these papers that you're writing and you're handing them to volunteer scientists who've got their own stuff going on, who maybe don't have time or the expertise to go through and check every single number. And like quite a lot of stuff slips through. So this article in the Times was really talking about the number of retractions that have happened in the scientific literature is increasing.

20:49Hannah Fry:And I think that with AI contributing to this landscape of like, just, you know, making it a tiny bit easier to make your paper sound amazing, just making it a tiny bit easier to like, Like, you know, play with your data in a particular way. Right. The number of retractions is increasing.

21:05Michael Stevens:Because AI, as like an LLM specifically, is going to be able to write things that sound right. This is what peer-reviewed papers tend to sound like. And so here's one. And it passes peer review because it's been engineered by an algorithm to sound like it should. And we don't wind up making any progress. We certainly don't do anything novel or revolutionary. I also wanted to say that I think we might discover that there are limits to what we can know that we don't currently know about. I think we could prove in some like Godelian mathematical way, for example, that we will never know what consciousness is and whether one thing is conscious or not.

21:50Michael Stevens:That might actually be for some really clever reason beyond the ability of a fellow conscious being. And we're just going to be left in the dark having to accept it on faith. And I think that I could see a far future where science is more about making people feel okay with what we cannot know. And it kind of takes the place of religion.

22:09Hannah Fry:You're such an optimist. I mean, I definitely agree with you about the limits of human knowledge and about accepting the limits. I don't think we're there yet, though. I do not think we're there yet.

22:20Michael Stevens:No.

22:21Hannah Fry:All right. Here's one for you, Michael. I know you're going to like this one. Okay. This is from Jacob. When hanging a post from my office, why do I feel compelled to hang it at the center? I could hang it anywhere. But why does it look best if equally between two endpoints? Is there an evolutionary reason for this? I've attached a photo of it hanging in my dingy office.

22:40Michael Stevens:Okay, let's show that photo. And then let's judge whether it's centered enough.

22:44Hannah Fry:Let me tell you what we're looking at here. So we've got this. It looks like one of those, it's been taken inside one of those sort of temporary buildings that you get on construction sites. That's sort of what it looks like. It's a corner of a room. It's got sort of cream paneled walls. It has a window to one side and then symmetrically between one of the wall panels hangs a glass framed photograph of a man with a guitar and a cowboy hat. Looks a bit like Bruce Springsteen from afar.

23:20Michael Stevens:First of all, I love that Jacob submitted a photo with his question. Is though, we would read his question and go, what do you mean centering a poster? I've never seen such a thing. I need a visual here. Oh, a poster. Now I know what you're talking about.

23:37Hannah Fry:Thank you for that picture, Jacob. I mean, I would say that aesthetically, there's a bit of headroom there to go, isn't there?

23:45Michael Stevens:Look, we don't need to judge Jacob's decoration, okay? He's asking about a psychological evolutionary phenomenon. Yeah.

23:56Hannah Fry:I don't think I don't remember coming across Bruce Springsteen posters in the history of evolution, but maybe I missed that lecture.

24:03Michael Stevens:Regardless of who it is, I think this is a really important question because I think it gets at like one of those, what is a human kind of things and why are we still here? Why did we not go extinct? I think that we really enjoy stuff that's difficult, stuff that is unnatural. I think we are a high skill based species where we don't hunt with the claws we're all born with. We have to like come up with strategies to hunt. And the only food sources available to these like little hairless naked apes that had no protection was the high skill stuff. Like, let's get let's get a mastodon or let's hunt an elephant.

24:49Michael Stevens:And that's going to require traps and cooperation and tools and spears and things that other animals just couldn't put together. And so humans that enjoyed things like, hey, look, this is symmetric or this is centered did better when it came to surviving with such soft, fleshy bodies. So now we are their children, right? We also really enjoy when things are unnecessarily rule following, when they're centered, when they're symmetric. And this has been our story forever. One of my favorite mysteries is why so many ancient stone axes are symmetric when they didn't need to be. It's been shown that making these, you know, what do you call it?

25:37Michael Stevens:When you nap stone to make a sharp point, making it symmetric or bifaced or giving it the shape that they seemingly all have took a lot more time than necessary to do the job. of killing an animal or ripping the skin off the bone or the meat off the bone. And so the only explanation seems to be that we just thought it was cool looking, that it showed a level of skill that meant that we were good potential mates, that we were going to be good at other things that humans needed to be good at, like cooperation, planning, thinking ahead, imagining. so yeah we want our posters to be centered because if we didn't we would have gone extinct

26:24Hannah Fry:it's like um i i often think about about the number of right angles that are in our lives yeah because nature does not have right angles then you don't find them i mean maybe very occasionally as a fluke but in every room in every building you ever walk into in every object that you own in every space that you encounter, we are surrounded by them, surrounded by this thing that is the most unnatural of human inventions. And I totally agree with you. It's like, why are we so obsessed with right angles? It's because they're symmetrical. It's because they're neat. It's because there's this precision to them that we are completely drawn to.

27:03Hannah Fry:I totally agree.

27:04Michael Stevens:That's right. There's an unnatural precision that shows a mastery of something that requires more skill than any other animal would require. And that's us. The only way we could survive was by having that high skill.

27:19Hannah Fry:So there you go, actually. I started off by slagging off your Bruce Springsteen poster, but actually now, now you've got the line of your window, you've got the really sad foam panels in the ceiling. You've got right angles and symmetry all over the place, Jacob. You are demonstrating yourself as uniquely human.

27:40Michael Stevens:I'm trying to make this picture bigger. Ah. Okay, so it's not Bruce Springsteen. It's a guy in a cowboy hat. Maybe it's Jacob himself. Oh, wouldn't that be cool? And we're sitting here not admiring it enough. Oh, hold on a second.

27:54Hannah Fry:Now that we've zoomed in, it's not Bruce Springsteen at all. It's Clint Black. Okay, this is a signed poster. Actually, he says it in his email. A signed poster from 1990. I don't know who Clint Black is, but I know what he looks like now, thanks to this image. I think at that point, maybe we'll go to a break, shall we?

28:39Hannah Fry:ever since.

28:40Michael Stevens:Radiotherapy remains one of the cornerstones of cancer treatment today. Every year, millions of people worldwide benefit from Cancer Research UK's work to make it more precise.

28:51Hannah Fry:Scientists are still refining how radiotherapy is delivered. And one example is an experimental treatment called flash radiotherapy, which delivers radiation in fractions of a second, up to a thousand times faster than standard radiotherapy.

29:06Michael Stevens:And early studies suggest that speed could make a real difference. Flash radiotherapy may cause up to 50 % less damage to healthy cells.

29:15Hannah Fry:But scientists don't yet know why healthy cells seem to be spared, so Cancer Research UK are working to answer that. Understanding it could be key to reducing side effects in the future.

29:27Michael Stevens:For more information about Cancer Research UK, their research and breakthroughs, and how you can support them, visit cancerresearchuk.org forward slash the rest is science.

30:03Michael Stevens:exclusively at Nespresso.com. When you want your spring break to feel like... And your kids' pool day to feel like... And your hotel bed to feel like... Ooh, and room service to feel like... Because at Hilton, hospitality feels like... Your cabana's ready. Would you like fresh towels? It matters where you stay. Book now at Hilton.com. Hilton for this day.

30:43Hannah Fry:All right, we're back. And this time I've got another question for you, Michael. How many holes does a straw have? One. Are you sure?

30:53Michael Stevens:Yeah, I'm sure. I mean, if we're talking about topological holes, holes that cannot be removed by gluing or ripping, one.

31:00Hannah Fry:This is a topic of much debate on the internet, you know. of how many holes does a straw have? Because as you say, some people say one, it's just, you know, you look through it, it's a hole, done. Other people say that there's two because there's one on this end and there's one on the other end. And in many ways, both groups of people, I think have a point, sort of.

31:21Michael Stevens:They have a point. I mean, you know, I did a video on how many holes a human has. And I think the bottom line is that here's what a hole is. It's a word. We made it up and it can mean whatever we want. And most of these debates are around what the word should mean. Should it mean like an individual entrance or is there some better definition? So look, by using a mathematical definition of a hole, the straw has one. You can imagine taking one end of the straw and stretching it open so that you wind up with a plate with a hole in the middle. Then it's really obvious that you've got one hole.

31:56Hannah Fry:I mean, of course, you are absolutely right. I'm going to come to your video on how many holes a human has in a moment, if I may.

32:04Michael Stevens:I'm really curious about what object you've brought, because we're jumping right into holes. Oh, yeah. Which you've established matters a lot to me.

32:11Hannah Fry:It does, evidently. Okay, but really what I want to talk about here is topology, which is basically the Alice in Wonderland of mathematical ideas. It's where you take a shape and the rules are that you can bend it and stretch it and deform it as much as you like, but you cannot cut it. right? You cannot cut it, you cannot rip it, you cannot crease it. And then people have these arguments extensively about how many holes things like straws or t-shirts or trousers have. Now, okay, while I agree with you that fundamentally, I think that a straw has one hole, you could say, well, hold on a second.

32:49Hannah Fry:If I cover up one end here, if I pinch one end of the straw, now how many holes does it have? Because it's sort of, you could say that it sort of does still does still have a hole. It's sort of a hole on the end, no?

33:01Michael Stevens:Right. Okay. So, I mean, I would say that, first of all, you have pinched a hole shut. All right. So you have, you're no longer talking about topology because you've committed a heteromorphism. It's now a different shape. You have glued one end shut and you don't have a hole anymore. You have a blind hole, which is a hole that you cannot go all the way through, but those can be removed by just, you know, moving the thing around like clay.

33:28Hannah Fry:Okay, sure. But then hold on a second. What about this glass? Does this glass have a hole in it?

33:33Michael Stevens:No.

33:33Hannah Fry:Why not? What are you talking about? It's got a hole right there.

33:36Michael Stevens:Yeah, but I can get rid of that hole without needing to use any glue or scissors. I can just, if we imagine that the glass is made of clay, I can open its orifice larger and larger until the whole thing is flat and it's a plate.

33:47Hannah Fry:Okay. So this is, I think, the fundamental key point. The two ways that you can look at this straw. One is that you can say that the surface is two dimensional, that the paper around the outside is 2D. And you can imagine blowing up this straw until it's the size of a balloon. Okay. So it's like this big round balloon. At which point then there are these two circles that are cut into it. Those are boundaries, right? So I think that exactly as you pointed out at the beginning, the problem is that the word hole means two different things. Sometimes it means tunnel and sometimes it means a boundary.

34:23Hannah Fry:So you could say that this straw, if it was the shape of a balloon, blown up to the shape of a balloon, would have two circles cut in it, two boundaries essentially. And so that is like the argument in favour of the people who say that a straw has two holes, one at each end.

34:40Michael Stevens:What field of mathematics worries about holes as boundaries? Because I do appreciate the difference between these two conceptions. a topologist would would would say this shape still has just one hole i think it's still a

34:55Hannah Fry:topologist it's just as the topologist is on looking at the surface rather than the the a three-dimensional object no i'm not sure i think you're right i don't i don't know if a i would say topologist but maybe i'm maybe i'm wrong um the other way to look at this straw is to say okay well imagine it was made of plasticine at which point you could well you could also cut off a tiny bit of it, make it shorter and shorter and shorter and shorter and shorter until you had just a little ring that was left over. At which point you're like, that's definitely got one hole. I mean, you're kind of crazy to imagine anything else.

35:28Hannah Fry:It's the same shape as a donut. A donut obviously has one hole. Right. So those are the two different ways to look at it, right? As though the surface is paper, two-dimensional, or the surface is a sort of physical object itself, a three-dimensional object itself.

35:44Michael Stevens:If we blow the straw up to a balloon. I like this way of thinking about it because now we've got seemingly two boundaries, though a topologist would say, but I could put my fingers into one of those boundaries and pull it and stretch the balloon until it was just a circle with a hole in the middle, one hole.

36:03Hannah Fry:Right. So this is exactly it, right? Is that it's like you've got two boundaries on the surface, but if you consider that the whole object is like solid, then it's one tunnel. So there's a difference between boundaries and tunnels, which is where the confusion comes in. So, okay, it's all right. It's not so bad on a straw, but what about a t-shirt? How many holes does a t-shirt have?

36:23Michael Stevens:Well, it has three holes, right? It's got four openings. The head hole and the torso hole, top and bottom are like one hole, but then it's got two more openings that join the central cavity of that hole, the armholes. So you can imagine shuffling them around and creating three very distinct through holes in a t-shirt.

36:47Hannah Fry:I really think the blowing it up into the balloon thing is really helpful here. Because if you imagine taking a t-shirt and blowing up into a balloon, then you've got four circles cut on the balloon. That's right. Exactly. But you're right that if it was, if the t-shirt itself is like made of plasticine, then essentially you have one tunnel, one central tunnel from top to bottom and then two additional tunnels that join that tunnel so three holes in total okay so mathematicians love playing around with these ideas of like taking really kind of crazy intricate shapes manipulating them asking whether a sphere can pass through itself asking whether you can like invert a donut all of these kind of things but the reason why this is fun and the reason why this matters I think is because of what happened with early life in the universe because it was basically playing this topological game um so uh the earliest earliest organisms they try to uh digest food in a sort of as as though they're a sack right so sort of imagine you know jellyfish here or anemones okay so they're they're they eat with the same hole that kind of goes into their stomach they digest it and then they sort of basically spit this waste out the same hole, which is inefficient.

38:02Hannah Fry:Pooping and eating out of the same hole is not a good idea, I would say.

38:06Michael Stevens:Yeah, I don't need to be told that.

38:11Hannah Fry:And then around about 550 million years ago, right? I mean, quite a long time ago, there was this worm-like creature that did the, I mean, it was the first one that did this really incredibly revolutionary thing. It essentially evolved a second hole, second boundary, but in effect made the hole into a tunnel. So it stopped being like a poke into the body of the creature and actually became a tunnel. A tunnel all the way through. So this creature, how long ago did it emerge? 550 million years ago.

38:45Michael Stevens:That doesn't seem that long ago, to be honest. for the first butthole, for the first living donut? The first butthole. That's great. That's cool.

38:57Hannah Fry:The first butthole. Michael, I love working with you. You're so right. That is the e-delition of the butthole. Is that what we call this video? We haven't even been around for a billion years. Anyway, the butthole as an innovation was genius. Okay. So, so much of life on the planet. I mean basically every creature that you can imagine that eats at one end and then ejects waste at the other is like following this same moment of revolution and this is the thing now you can eat continuously right you've got what you've done is you've turned yourself topologically into a different shape and now you can have this like assembly line of food and that is what allowed animals to get way bigger, way more complex.

39:45Michael Stevens:It's a miracle. That's why I think eating on the toilet is almost a religious experience. It's a celebration of the fundamental donut-ness of my body.

39:55Hannah Fry:Yeah, right? Because we are. We are like squish us down. We are all these donut shapes. It's also, though, the reason why our brains and our eyes and our nose and our mouth are all in the same place. Because think of us as though we are just a tube that's existing through the world that's like continually looking for food. Sort of imagine us worm shaped, right? And we are all of our senses packed up towards the like entrance to our like fundamental tube.

40:26Michael Stevens:Yeah, that's right.

40:27Hannah Fry:It creates a bit of a problem, though, because you need the tube, the kind of the esophagus to like go through the middle, right? You want the brain to kind of exist all the way around the tube. You don't want the brain on one side and nothing on the other. So there are some very simple animals, even antropods, I think, where the esophagus literally goes through the middle of their brain. So if they swallow a chunk of food that is too big, they can give themselves brain damage, which is not great. I'm glad that's not us. Do you know how humans worked out our way around it? Well, not humans, but I mean mammals more generally.

41:02Hannah Fry:No, no. How? So if you think we have like, you're eating through your mouth, you're breathing through your nose, which is above your mouth. But then once it gets to your throat, they have to swap over. You have to go to your lungs.

41:19Michael Stevens:The nose goes into the sinuses. Yeah. And they all connect in the throat, the mouth hole and the nose hole. But then there is a division between the esophagus and the trachea for air and food. And for humans, that's a dangerous connection. It's much easier for us to choke than like a dog or a bear.

41:45Hannah Fry:Do you know what? I thought I understood this and now I'm thinking about it. I'm not sure I completely do this little bit. Oh, there we go. Look at this. Yeah.

41:52Michael Stevens:So here you can see the mouth opens up and comes down this way into the throat, but the nose goes into this big open area called the sinuses. And this connects back into throat to the throat as well. They come down and here we have this division between the esophagus and the trachea. So air that we breathe comes down here to the lungs and food is squeezed by the muscles in the esophagus to get to the stomach.

42:21Hannah Fry:So here's the problem is that you need the stomach to go in the middle of the body. Right. But at the nose, it's like the airway is on top. It's sort of it's kind of at the back, as it were. and then they switch over, they cross over in that section where the air supply starts to come to the front, right? So originally it's at the back and now it comes to the front. You've got this crossover, the switch over. And it's the topological solution to the fact that we need our brains to be around our whole body. You need the tube to be in the center. And how do you do it?

42:55Michael Stevens:Yeah. Are you with me? I'm with you. And it makes me appreciate the existential quality of choking, that it's fundamentally because of this crossover that has to happen.

43:07Hannah Fry:The crossover has to happen. Exactly. The brain's on top, the nerve cord is on the bottom. You've got to have your connecting nerves physically to wrap around the esophagus to link up so the brain can act around the entire body. And so what you end up with is this like switch over. All right. So we're all these tubes munching along, eyes and ears and stuff all at the top. But then we also, of course, have breathing apparatus attached, right? Our noses. Now, I know that you have done a video on this. Tell me how many holes are there in the human body in topological terms?

43:46Michael Stevens:Okay. To make it brief, I'll say that we need to define how big something has to be to be a hole. Like if a single blood cell can pass through it, then the body has millions of holes, right? The urethra is a hole because you can get up into the bladder, through the ureters, to the kidneys, blah, blah, blah, blah, blah. So I think we need to go bigger than that. If we go 60 microns, all right, the thickness of a human hair, if it can come in one hole and come out another, we've got ourselves a through hole. And as it turns out, humans have eight entrances, meaning we have seven topological holes.

44:21Hannah Fry:Seven topological holes. Ears don't count, Paws don't count. Female reproductive organs don't count. That's right.

44:27Michael Stevens:The ears don't count because the eardrum blocks any continuous passage from the ear into anything else. At the scale of a human hair, right? A neutrino can pass right through the eardrum. A neutrino can pass right through reproductive organs and go wherever it wants. But a little spaceship 60 microns wide, it's going to be like, guys, we're stuck. We've got eight ways in and out. And that means we've got seven holes. There was a program that I was doing a few years ago about evolution.

45:01Hannah Fry:And we were talking about how all creatures were tubes. And I mentioned the fact that you had done this seven-holed human thing and was extremely excited about it and just absolutely loved it. And so I also, by the way, at the time was quite obsessed with wood turning videos on the internet, which I'd also mentioned on the show. Anyway, someone made me, wood turned me, a topological model of a human body. Oh, it's beautiful.

45:30Michael Stevens:Isn't that gorgeous? You know, it looks like the cylinder of a revolver. That's right. There's a central hole that it could pivot around. And then there are six holes for the six bullets. And that's the human body. Topologically, that's the same thing. We haven't discussed what these other six holes are. Like we know that there's this hole from the mouth to the anus, but there are six more tunnels that all join in to that same tube. Two of them are the nostrils. You've got your left and your right nostril. They meet together in the sinuses and then they connect up with the throat. And then you have on both eyes, you have two holes that are called your lacrimal punctum and they absorb your tears.

46:16Michael Stevens:If you're actually crying, they can't keep up. And so the tears come down on your face. But normally the wetness of your eyes is it's like squirted on the eye. And then it drains through these two holes we have at the corners of our eyes. And that goes into the sinuses as well.

46:31Hannah Fry:The back of your throat.

46:32Michael Stevens:That's why when you get really teary, your nose runs. A lot of that crying nose runny liquid is actually tears that are in your nose now. So you've got those four puncta, two in each eye, two nostrils. That's the six holes that all join up and they are greater than 60 microns across. So they fit my definition of a hole that, you know, you could travel through. You stick a hair through and pull it out somewhere else. So that's all seven of them. You've got the.

46:58Hannah Fry:Here you go. Mouth to bum right here in the middle.

47:01Michael Stevens:It's the middle one, let's say. Yeah. And then you've got the two nostrils. Nostril nostril right there. And then you've got the four lacrimal puncta.

47:09Hannah Fry:Left eye, right eye, human.

47:12Michael Stevens:Yep. And they all connect, but you can, and this is hard to do if you're just listening, but you can imagine all of those tunnels being morphed and continuously deformed away from each other to form exactly the shape Hannah is holding.

47:28Hannah Fry:That's us. That's us right there. Just the really loving right angles as well. This and right angles. That's the whole description of humanity that you ever need. You know what? Forget about the Arecibo message.

47:41Michael Stevens:this is what we should have sent yeah they would have gotten it like in general this is us i mean it'd be better than the other one they sent frankly we could have sent a board of wood with two holes drilled in it and said this is our pants drill a third hole it's a shirt yeah

48:01Hannah Fry:yeah unless unless it's a button-up shirt in which case the first one would do

48:05Michael Stevens:Like, oh, yes, yes. And by the way, like we all in general have seven holes. But if you've got piercings, those add additional holes.

48:17Hannah Fry:Oh, gosh. Oh, they do. You're absolutely right. I need to put in a teeny tiny, especially a nose piercing. I need to put in a teeny tiny one in there.

48:25Michael Stevens:And not to get too into the weeds, but some people have additional holes through their sinuses. I forget what the medical term is for it, but we don't really know if we have them unless we've had like scans or like nasal problems. But you can live your whole life not knowing that you've got an eighth hole hidden inside your head. Or someone with two buttholes. There aren't many of them, but I've met some people that I've been suspicious. I'm like, you've got two down there, don't you? You're talking out of your second butthole. Yeah, it requires a whole different language, but it's possible.

49:01Hannah Fry:Now that we've done an evolutionary history of the butthole, I think we put this episode to bed, Michael. That was an enjoyable romp.

49:09Michael Stevens:Let's flush all of it. All right, guys. Thanks for joining us. I'm glad you've got your seven plus holes. And we hope you bring them back next time.

49:21Hannah Fry:Certainly do. If you have any questions you'd like us to answer, anything you want to send us in, you can send us anything you like. The rest is science at goalhanger.com.

49:30Michael Stevens:And you can join our newsletter at therestis.com slash science.

49:35Hannah Fry:We're going to be back next Thursday with another edition of Field Notes and on Tuesday with our usual normal episode where we will not be talking about buttholes. Stay there. Probably not.

49:45Michael Stevens:But until then, stay curious.