WEBVTT 00:00:00.000 --> 00:00:01.940 Welcome back to the Deep Dive. I have to admit, 00:00:02.080 --> 00:00:04.240 when I first saw the stack of sources for today, 00:00:04.419 --> 00:00:08.099 I had a moment of hesitation. I looked at the 00:00:08.099 --> 00:00:10.859 title and I thought, OK, really, are we going 00:00:10.859 --> 00:00:12.779 there? Because usually when you see this topic 00:00:12.779 --> 00:00:16.239 online, it's well, it's a comment section war. 00:00:16.399 --> 00:00:19.460 It is usually a very loud, very angry argument. 00:00:19.539 --> 00:00:23.210 Yes, it gets heated. To put it mildly. Exactly. 00:00:23.710 --> 00:00:26.269 But then I started reading through the materials 00:00:26.269 --> 00:00:28.870 you pulled, the historical records, the ancient 00:00:28.870 --> 00:00:31.350 cosmology papers, the studies on psychology. 00:00:31.629 --> 00:00:33.670 And I realized pretty quickly that this isn't 00:00:33.670 --> 00:00:35.530 actually a debate about the shape of a planet. 00:00:36.109 --> 00:00:38.469 I mean, it is, but that's the boring part. That 00:00:38.469 --> 00:00:40.149 is the least interesting part of the conversation, 00:00:40.329 --> 00:00:42.649 honestly. The real story is so much bigger. Right. 00:00:42.969 --> 00:00:45.570 What this actually is, is a massive sprawling 00:00:45.570 --> 00:00:48.109 story about human perception. It's about history. 00:00:48.289 --> 00:00:50.189 It's about how we know what we know. And honestly, 00:00:50.390 --> 00:00:52.670 it's about the stories we tell ourselves to feel 00:00:52.670 --> 00:00:55.049 smart. It is a journey through the evolution 00:00:55.049 --> 00:00:58.320 of thought. We are going to look at how humanity 00:00:58.320 --> 00:01:01.140 figured out where we are in the universe. And 00:01:01.140 --> 00:01:03.460 the road to getting there is much stranger than 00:01:03.460 --> 00:01:05.939 just people used to be dumb and now we are smart. 00:01:06.140 --> 00:01:08.219 That is the vibe I want to shatter today. We 00:01:08.219 --> 00:01:10.579 are diving into the flat earth, but we aren't 00:01:10.579 --> 00:01:12.980 doing the YouTube debunking video thing. No, 00:01:12.980 --> 00:01:15.379 no, not at all. We are going back to ancient 00:01:15.379 --> 00:01:17.739 Mesopotamia. We are going to the royal courts 00:01:17.739 --> 00:01:20.079 of the Ming Dynasty. And we are definitely going 00:01:20.079 --> 00:01:22.500 to spend some time in the 19th century to figure 00:01:22.500 --> 00:01:25.159 out who lied to us about Christopher Columbus. 00:01:25.640 --> 00:01:27.439 That is the part that usually surprises people 00:01:27.439 --> 00:01:30.260 the most, that big reveal. So let's set the stage 00:01:30.260 --> 00:01:32.819 with a bit of a double twist hook just to orient 00:01:32.819 --> 00:01:36.439 you. Twist number one, the ancients, and I'm 00:01:36.439 --> 00:01:39.400 talking the really ancient civilizations, absolutely 00:01:39.400 --> 00:01:42.040 thought the world was flat. It was intuitive. 00:01:42.159 --> 00:01:43.980 It was obvious. And we are going to talk about 00:01:43.980 --> 00:01:47.299 why. But twist number two, the people you think 00:01:47.299 --> 00:01:49.200 thought it was flat, the medieval Europeans, 00:01:49.599 --> 00:01:52.379 the peasants, the church, the people in the so 00:01:52.379 --> 00:01:55.420 -called dark ages actually didn't. That is the 00:01:55.420 --> 00:01:59.120 big myth. If you grew up thinking Columbus sailed 00:01:59.120 --> 00:02:01.079 to prove the world was round while everyone else 00:02:01.079 --> 00:02:03.239 was terrified he'd fall off the edge, you were 00:02:03.239 --> 00:02:05.459 told a lie. You were told a story. A literal 00:02:05.459 --> 00:02:08.139 fiction invented hundreds of years later for, 00:02:08.199 --> 00:02:10.560 you know, political reasons. My entire third 00:02:10.560 --> 00:02:12.780 grade history class feels like a betrayal right 00:02:12.780 --> 00:02:15.919 now. We are going to fix that. But the mission 00:02:15.919 --> 00:02:18.699 for this Deep Dives is to unpack what historians 00:02:18.699 --> 00:02:22.759 call this archaic conception. We need to understand 00:02:22.759 --> 00:02:24.939 why the flat Earth model existed in the first 00:02:24.939 --> 00:02:27.599 place, why it vanished in the West, why it stuck 00:02:27.599 --> 00:02:30.240 around in the East for so long, and the really 00:02:30.240 --> 00:02:32.960 fascinating, somewhat terrifying reasons why 00:02:32.960 --> 00:02:34.979 it has suddenly returned in the 21st century. 00:02:35.080 --> 00:02:37.680 And we have a really diverse stack of sources 00:02:37.680 --> 00:02:40.039 today. We've got translations of Babylonian tablets. 00:02:40.139 --> 00:02:42.379 We've got analysis of Chinese astronomy. We've 00:02:42.379 --> 00:02:45.219 got the specific history of the modern flat Earth 00:02:45.219 --> 00:02:47.580 resurgence from Wikipedia and some sociological 00:02:47.580 --> 00:02:49.599 studies. So let's start at the very beginning. 00:02:49.979 --> 00:02:52.360 The floating log. The floating log. This brings 00:02:52.360 --> 00:02:55.280 us to Thales of Miletus. I read that in the notes, 00:02:55.300 --> 00:02:58.840 Thales of Miletus, around 550 BC, and the image 00:02:58.840 --> 00:03:01.419 is just so specific. He didn't say the earth 00:03:01.419 --> 00:03:04.120 was a rock or a mountain. He said it was a log 00:03:04.120 --> 00:03:06.479 floating in water. It sounds funny to modern 00:03:06.479 --> 00:03:08.800 ears, but we have to put ourselves in the headspace 00:03:08.800 --> 00:03:11.599 of an early observer. We need to distinguish 00:03:11.599 --> 00:03:15.000 between ignorance and observation. Okay. If I 00:03:15.000 --> 00:03:16.539 asked you to forget everything you learned in 00:03:16.539 --> 00:03:19.120 school, Forget the globes, forget the NASA photos, 00:03:19.280 --> 00:03:21.680 forget satellites, and just walk outside and 00:03:21.680 --> 00:03:23.699 describe the world based strictly on your sensory 00:03:23.699 --> 00:03:26.199 data. What would you say? Well, if I'm standing 00:03:26.199 --> 00:03:30.139 in a field, it looks flat, maybe a bit bumpy 00:03:30.139 --> 00:03:33.240 with hills. But generally, the horizon is a straight 00:03:33.240 --> 00:03:35.860 line. It doesn't curve. Precisely. If you're 00:03:35.860 --> 00:03:38.400 on a boat looking at the ocean, the horizon is 00:03:38.400 --> 00:03:41.259 a flat line 360 degrees around you. Yeah. If 00:03:41.259 --> 00:03:43.629 you're in the desert, it's a flat plane. The 00:03:43.629 --> 00:03:46.009 intuitive view, the default factory setting for 00:03:46.009 --> 00:03:48.509 the human brain is a flat earth. It is what your 00:03:48.509 --> 00:03:51.150 eyes tell you every single day. So early civilizations 00:03:51.150 --> 00:03:53.050 weren't being anti -science. They were being 00:03:53.050 --> 00:03:55.409 empiricists. They were trusting their primary 00:03:55.409 --> 00:03:58.330 data source. They were being literalists. They 00:03:58.330 --> 00:04:01.250 were building a model of the world based on the 00:04:01.250 --> 00:04:03.650 evidence they could gather themselves. And this 00:04:03.650 --> 00:04:06.150 connects to the floating log. Why water? Right. 00:04:06.189 --> 00:04:08.090 Why always water? If you look at the ancient 00:04:08.090 --> 00:04:12.169 Near East, Egypt, Mesopotamia. Their entire existence 00:04:12.169 --> 00:04:16.509 depended on water. The Nile, the Tigris, the 00:04:16.509 --> 00:04:20.589 Euphrates. Water was life. And the ocean surrounding 00:04:20.589 --> 00:04:23.209 the land. Right. So in the Near Eastern mythology, 00:04:23.350 --> 00:04:26.170 and specifically in the Egyptian texts, the world 00:04:26.170 --> 00:04:29.310 is portrayed as a disk that rose out of a massive, 00:04:29.389 --> 00:04:32.490 infinite, chaotic ocean. The cosmic ocean. In 00:04:32.490 --> 00:04:34.990 Egypt, they called it Nun. It was the primordial 00:04:34.990 --> 00:04:37.470 waters. The earth was just a bubble or a mound 00:04:37.470 --> 00:04:40.660 of dry land floating in this endless sea. It 00:04:40.660 --> 00:04:42.480 makes sense, right? If you dig down into the 00:04:42.480 --> 00:04:44.480 earth, what do you eventually hit? Water, groundwater. 00:04:44.759 --> 00:04:46.500 And if you travel far enough in any direction, 00:04:46.579 --> 00:04:49.300 what do you hit? The ocean. So logically, the 00:04:49.300 --> 00:04:51.360 land must be floating on top of the water. There's 00:04:51.360 --> 00:04:53.439 water below and water all around. It's a very 00:04:53.439 --> 00:04:55.879 coherent, if incorrect, picture. That actually 00:04:55.879 --> 00:04:57.800 makes a disturbing amount of sense if you don't 00:04:57.800 --> 00:05:01.439 know about gravity or geology. But the part of 00:05:01.439 --> 00:05:03.540 this ancient worldview that I found most beautiful 00:05:03.540 --> 00:05:07.720 and also kind of claustrophobic is the sky. They 00:05:07.720 --> 00:05:10.269 didn't see the sky as empty space. No, the concept 00:05:10.269 --> 00:05:13.610 of space is very modern. For the ancients, the 00:05:13.610 --> 00:05:16.990 sky was a solid object. This is the firmament. 00:05:17.170 --> 00:05:19.889 The rakia in Hebrew, right. I saw that word in 00:05:19.889 --> 00:05:22.310 the sources. Yes. The word implies something 00:05:22.310 --> 00:05:25.310 hammered out, like a metal sheet or a dome. In 00:05:25.310 --> 00:05:27.629 the biblical view, and the Babylonian view before 00:05:27.629 --> 00:05:32.040 it, the sky is a solid, arched structure. It's 00:05:32.040 --> 00:05:34.639 like a glass snow globe. So the Earth is the 00:05:34.639 --> 00:05:36.459 flat bottom of the snow globe, and the firmament 00:05:36.459 --> 00:05:38.980 is the glass dome over the top. Exactly. And 00:05:38.980 --> 00:05:41.100 its job is to hold back the waters above. Wait, 00:05:41.180 --> 00:05:42.959 waters above? So there's water on top of the 00:05:42.959 --> 00:05:45.300 sky dome? They believed there was water up there, 00:05:45.420 --> 00:05:47.819 which explains why the sty is blue, like the 00:05:47.819 --> 00:05:50.399 ocean, and why it rains. Of course. The firmament 00:05:50.399 --> 00:05:52.800 had windows or sluice gates that God could open 00:05:52.800 --> 00:05:55.680 to let the water in. Rain wasn't a meteorological 00:05:55.680 --> 00:05:57.860 cycle. It was a deliberate opening of the cosmic 00:05:57.860 --> 00:06:00.759 plumbing. That is such a cozy, enclosed image. 00:06:00.980 --> 00:06:03.120 It's like living in a house. The floor is the 00:06:03.120 --> 00:06:05.959 earth. The roof is the firmament. And the stars. 00:06:06.199 --> 00:06:09.240 What about the stars in this model? In this model, 00:06:09.360 --> 00:06:11.740 the stars aren't distant suns billions of miles 00:06:11.740 --> 00:06:15.339 away. They are lights embedded in the dome. Think 00:06:15.339 --> 00:06:18.139 of jewels set into a ceiling or lamps hanging 00:06:18.139 --> 00:06:21.060 from a roof. The sun and moon were also just 00:06:21.060 --> 00:06:23.680 larger lights moving along tracks set into this 00:06:23.680 --> 00:06:26.740 dome. It's interior decorating on a cosmic scale. 00:06:27.180 --> 00:06:29.420 It creates a universe that is focused entirely 00:06:29.420 --> 00:06:32.860 on humanity. We are in the center, on the stage, 00:06:32.959 --> 00:06:34.899 and the whole universe is just the theater building 00:06:34.899 --> 00:06:38.100 around us. Very anthropocentric. And the Greeks. 00:06:38.180 --> 00:06:39.899 I feel like we always give the Greeks a pass 00:06:39.899 --> 00:06:42.980 as the smart ones, the math guys. But the early 00:06:42.980 --> 00:06:44.959 Greek poets were right there with the Babylonians 00:06:44.959 --> 00:06:47.579 on this. Oh, absolutely. If you read Homer or 00:06:47.579 --> 00:06:50.459 Hesiod, we're talking 8th century BC, way before 00:06:50.459 --> 00:06:52.699 the philosophers we know. They described the 00:06:52.699 --> 00:06:55.079 shield of Achilles. This is a famous passage 00:06:55.079 --> 00:06:56.959 in the Iliad where Hephaestus makes a shield 00:06:56.959 --> 00:07:00.079 and on it he depicts the entire cosmos. And it's 00:07:00.079 --> 00:07:02.339 a dis. A flat circle. A flat circle surrounded 00:07:02.339 --> 00:07:05.839 by the river Okeanos. Okeanos wasn't just a body 00:07:05.839 --> 00:07:10.240 of water to them. It was a titan. A god, a river 00:07:10.240 --> 00:07:13.259 that flowed back into itself in a circle, bounding 00:07:13.259 --> 00:07:15.439 the edges of the world. It was the begetter of 00:07:15.439 --> 00:07:18.160 all life. That word edges is doing a lot of work 00:07:18.160 --> 00:07:20.240 there. That's the scary part. If there is an 00:07:20.240 --> 00:07:23.740 edge, there is a drop. And that fear of the edge 00:07:23.740 --> 00:07:26.360 is something that permeates these early cosmologies. 00:07:26.560 --> 00:07:29.079 It's why the cosmic ocean is often seen as dangerous 00:07:29.079 --> 00:07:31.899 or chaotic. It's the boundary between the known 00:07:31.899 --> 00:07:35.300 world and the unknowable abyss. This brings us 00:07:35.300 --> 00:07:37.459 to the pre -Socratic philosophers. This is a 00:07:37.459 --> 00:07:39.360 group I've always found fascinating because they 00:07:39.360 --> 00:07:42.139 are trying to move away from Zeus did it to here 00:07:42.139 --> 00:07:44.360 is a physical explanation, even if the physical 00:07:44.360 --> 00:07:46.720 explanation is wild. They're the bridge between 00:07:46.720 --> 00:07:48.920 mythology and science. They're asking the right 00:07:48.920 --> 00:07:50.939 questions, even if they get the wrong answers. 00:07:51.120 --> 00:07:53.420 We mentioned Thales and his log, but then you 00:07:53.420 --> 00:07:56.399 have his student, Anaximander, and his theory 00:07:56.399 --> 00:07:59.540 is, well... It's industrial. It's very specific. 00:07:59.779 --> 00:08:01.560 The cylinder. He didn't think it was a flat, 00:08:01.600 --> 00:08:04.560 thin disk. He thought the Earth was a stone column 00:08:04.560 --> 00:08:07.920 or a cylinder, like a drum. And we live on one 00:08:07.920 --> 00:08:10.199 of the flat surfaces, the top. The height was 00:08:10.199 --> 00:08:12.160 about one -third of its diameter, according to 00:08:12.160 --> 00:08:15.180 him. So the Earth is a hockey puck, a very thick 00:08:15.180 --> 00:08:17.379 hockey puck suspended in space. A hockey puck, 00:08:17.500 --> 00:08:20.680 yes. But here is the genius of an axemander, 00:08:20.800 --> 00:08:23.839 even though his shape was wrong. He had to answer 00:08:23.839 --> 00:08:26.620 the question, what is holding the puck up? Right. 00:08:26.839 --> 00:08:29.819 Thales said water. But Anaximander asked, what 00:08:29.819 --> 00:08:32.240 is the water resting on? It's turtles all the 00:08:32.240 --> 00:08:34.039 way down, right? Right. You need a base. You 00:08:34.039 --> 00:08:36.399 always need a final turtle. Anaximander said, 00:08:36.559 --> 00:08:39.759 nothing. He said the Earth stays in place because 00:08:39.759 --> 00:08:42.299 it is equidistant from everything else in the 00:08:42.299 --> 00:08:45.320 universe. It is in the center. Because it is 00:08:45.320 --> 00:08:47.820 in the center, it has no reason to move up, down, 00:08:47.980 --> 00:08:50.139 left, or right. It is held in place by equilibrium. 00:08:50.669 --> 00:08:52.750 That is actually incredibly sophisticated. He's 00:08:52.750 --> 00:08:55.149 talking about forces, essentially, rather than 00:08:55.149 --> 00:08:57.409 a giant turtle or a pillar. He's using logic, 00:08:57.450 --> 00:09:00.169 not just an image. Exactly. It's a huge leap 00:09:00.169 --> 00:09:02.570 in abstract thinking. He's the first person we 00:09:02.570 --> 00:09:04.490 know of to imagine the Earth floating freely 00:09:04.490 --> 00:09:07.570 in space. But then you have Anaximenes, who comes 00:09:07.570 --> 00:09:09.970 along and says, no, that's too complicated. It's 00:09:09.970 --> 00:09:13.330 a leaf. A leaf. He went back to the flat disk 00:09:13.330 --> 00:09:16.490 idea. He said the Earth is flat and broad, and 00:09:16.490 --> 00:09:18.830 because it is broad, it rides on the air like 00:09:18.830 --> 00:09:21.279 a leaf or a kite. The air pressure underneath 00:09:21.279 --> 00:09:23.960 holds it up. He also thought the sun and moon 00:09:23.960 --> 00:09:27.000 were flat, fiery bodies that also floated on 00:09:27.000 --> 00:09:29.620 the air. Okay, so we have a log, a hockey puck, 00:09:29.820 --> 00:09:32.440 and a kite. And then there was Archelaus with 00:09:32.440 --> 00:09:34.320 the saucer. Archelaus is interesting because 00:09:34.320 --> 00:09:37.320 he was trying to solve a specific observational 00:09:37.320 --> 00:09:39.960 problem. This shows they weren't just making 00:09:39.960 --> 00:09:42.200 things up. They were wrestling with data. Okay, 00:09:42.240 --> 00:09:44.220 what was the problem? Travelers had noticed that 00:09:44.220 --> 00:09:46.659 the sun rises and sets at different times depending 00:09:46.659 --> 00:09:49.649 on where you are east or west. If the Earth were 00:09:49.649 --> 00:09:51.830 perfectly flat, everyone would see the sunrise 00:09:51.830 --> 00:09:54.590 at the exact same instant. Right. Pop. The sun 00:09:54.590 --> 00:09:57.029 clears the horizon. Everyone sees it. But they 00:09:57.029 --> 00:09:59.710 knew that wasn't true. So Archelaus suggested 00:09:59.710 --> 00:10:02.090 the Earth was depressed in the middle, like a 00:10:02.090 --> 00:10:05.009 bowl or a saucer. The raised rim meant that the 00:10:05.009 --> 00:10:07.110 sun would be blocked for some people while visible 00:10:07.110 --> 00:10:09.750 to others. So he's twisting the flat Earth model 00:10:09.750 --> 00:10:11.850 into a pretzel to try and make it fit the data. 00:10:11.929 --> 00:10:14.549 He's patching the bugs in the code. That is the 00:10:14.549 --> 00:10:16.750 hallmark of this era. Yeah. They are gathering 00:10:16.750 --> 00:10:20.440 data. astronomical data, travel logs, and they 00:10:20.440 --> 00:10:23.080 were trying to cram it into the flat framework 00:10:23.080 --> 00:10:25.200 because that's what their intuition tells them 00:10:25.200 --> 00:10:27.340 must be true. Before we leave the ancient flat 00:10:27.340 --> 00:10:29.559 Earth, we have to talk about the Norse because 00:10:29.559 --> 00:10:32.379 their version of the cosmic ocean isn't just 00:10:32.379 --> 00:10:35.519 water, it's a monster. The Norse cosmology is 00:10:35.519 --> 00:10:39.120 extremely visceral. You have Midgard, the Earth, 00:10:39.240 --> 00:10:42.059 which is a flat, circular realm, and surrounding 00:10:42.059 --> 00:10:44.720 it is the great ocean. But the ocean isn't just 00:10:44.720 --> 00:10:47.960 empty, it is the home of Jormungandr. A Midgard 00:10:47.960 --> 00:10:50.700 serpent. A snake so large that it encircles the 00:10:50.700 --> 00:10:52.899 entire world and bites its own tail. I've always 00:10:52.899 --> 00:10:55.340 loved that image, the Ouroboros on a global scale, 00:10:55.419 --> 00:10:58.279 but looking at it through this lens, it's a containment 00:10:58.279 --> 00:11:00.919 field. It is. In the Gylfaginning, one of the 00:11:00.919 --> 00:11:04.299 key Norse texts, the ocean is described as impassable. 00:11:04.559 --> 00:11:07.360 The snake represents the boundary. It's the do 00:11:07.360 --> 00:11:10.139 -not -enter sign for humanity. The reason the 00:11:10.139 --> 00:11:12.820 oceans don't drain off the edge is because this 00:11:12.820 --> 00:11:15.259 living force is binding it all together. It really 00:11:15.259 --> 00:11:16.860 highlights the difference between the modern 00:11:16.860 --> 00:11:19.600 view of the ocean and the ancient one. To us, 00:11:19.600 --> 00:11:21.940 the ocean is a highway. We ship cargo across 00:11:21.940 --> 00:11:25.200 it. To them, the ocean was the barrier. It was 00:11:25.200 --> 00:11:28.080 the end of reality. And that psychological barrier, 00:11:28.259 --> 00:11:30.500 the idea that there is a limit to the world, 00:11:30.620 --> 00:11:32.779 is something that takes a long time to break. 00:11:33.240 --> 00:11:35.700 It requires a shift from trusting your gut to 00:11:35.700 --> 00:11:38.379 trusting your math. Which segues perfectly into 00:11:38.379 --> 00:11:40.940 part two, the great shift. The Greeks start seeing 00:11:40.940 --> 00:11:43.519 curves. This is one of the most important moments 00:11:43.519 --> 00:11:45.700 in intellectual history. It happens in Greece, 00:11:45.779 --> 00:11:47.600 starting with Pythagoras in the 6th century BC, 00:11:47.779 --> 00:11:50.559 who seems to have suggested it for aesthetic 00:11:50.559 --> 00:11:52.720 reasons. He just thought spheres were the most 00:11:52.720 --> 00:11:55.159 perfect shape. Of course he did. But it really 00:11:55.159 --> 00:11:58.080 solidifies with Aristotle around 330 BC. No, 00:11:58.120 --> 00:11:59.779 why did they change their minds? Did someone 00:11:59.779 --> 00:12:02.580 sail around the world? No, and that's the beauty 00:12:02.580 --> 00:12:04.840 of it. They figured it out without leaving the 00:12:04.840 --> 00:12:07.580 Mediterranean. It wasn't about travel. It was 00:12:07.580 --> 00:12:10.639 about deduction and observation. So Aristotle 00:12:10.639 --> 00:12:12.899 lays out three main arguments in his book on 00:12:12.899 --> 00:12:15.700 the heavens. And these are arguments that, spoiler 00:12:15.700 --> 00:12:17.980 alert, modern flat earthers still struggle to 00:12:17.980 --> 00:12:20.580 answer. They're simple, elegant, and devastating 00:12:20.580 --> 00:12:23.610 to the flat model. The first one is the stars. 00:12:24.629 --> 00:12:26.669 Aristotle points out that travelers going to 00:12:26.669 --> 00:12:29.110 Egypt see stars that are invisible in northern 00:12:29.110 --> 00:12:31.750 Greece, and stars that are visible in both places 00:12:31.750 --> 00:12:34.190 appear higher in the sky in the south and lower 00:12:34.190 --> 00:12:37.129 in the north. So the dome of stars is shifting 00:12:37.129 --> 00:12:39.289 relative to your position. The further south 00:12:39.289 --> 00:12:41.789 you go, the more of the southern sky you see. 00:12:41.929 --> 00:12:44.490 Right. If the Earth were flat, moving a few hundred 00:12:44.490 --> 00:12:47.009 miles north or south shouldn't change the angle 00:12:47.009 --> 00:12:48.710 of the stars that much, unless the stars were, 00:12:48.789 --> 00:12:51.590 like... Really close. But the shift happens uniformly. 00:12:52.049 --> 00:12:54.889 It implies you are walking along a curve, and 00:12:54.889 --> 00:12:57.190 as you do, your personal horizon is tilting. 00:12:57.350 --> 00:13:00.009 Okay, that's clever. Argument number two, the 00:13:00.009 --> 00:13:02.750 moon. The lunar eclipse. This is my favorite 00:13:02.750 --> 00:13:05.250 one. When the Earth passes between the sun and 00:13:05.250 --> 00:13:08.830 the moon, it casts a shadow on the moon. Aristotle 00:13:08.830 --> 00:13:11.750 simply pointed out. Look at the shadow. It is 00:13:11.750 --> 00:13:14.450 always a curve. The edge of the shadow is always 00:13:14.450 --> 00:13:16.590 part of a circle. And a flat disk could cast 00:13:16.590 --> 00:13:18.529 a circular shadow, right? Like a dinner plate. 00:13:18.690 --> 00:13:21.470 Only if the dinner plate is facing the sun directly, 00:13:21.690 --> 00:13:25.110 perfectly face on. But eclipses happen at all 00:13:25.110 --> 00:13:27.529 different times of night with the Earth in all 00:13:27.529 --> 00:13:30.610 different orientations relative to the sun. If 00:13:30.610 --> 00:13:33.070 the Earth were a flat disk, eventually you would 00:13:33.070 --> 00:13:35.210 get a shadow that looked like a thin line at 00:13:35.210 --> 00:13:38.070 the edge of the plate or an oval. But it's not. 00:13:38.330 --> 00:13:41.070 It is always a circle. The only shape that casts 00:13:41.070 --> 00:13:43.649 a circular shadow from every single angle is 00:13:43.649 --> 00:13:45.990 a sphere. That is the mic drop moment for me. 00:13:46.029 --> 00:13:47.470 You can see it with your own eyes. You don't 00:13:47.470 --> 00:13:49.669 need a telescope. You just need an eclipse. And 00:13:49.669 --> 00:13:51.529 the third one is the ships. We've all heard this 00:13:51.529 --> 00:13:53.990 one, but it's powerful. A ship sailing away from 00:13:53.990 --> 00:13:55.970 you doesn't just get smaller until it's a dot. 00:13:56.429 --> 00:13:59.850 It sinks. The hull disappears first. Then the 00:13:59.850 --> 00:14:01.929 sails. Then the little flag on the top of the 00:14:01.929 --> 00:14:03.990 mast. It's going over the curve of the Earth. 00:14:04.190 --> 00:14:07.490 So by 330 BC, the intellectual heavyweights know 00:14:07.490 --> 00:14:10.360 it's a sphere. But knowing it's a sphere and 00:14:10.360 --> 00:14:12.539 knowing how big it is are two different things. 00:14:12.860 --> 00:14:15.860 Enter Eratosthenes. Eratosthenes, the librarian 00:14:15.860 --> 00:14:21.000 of Alexandria, around 240 BC. This story is often 00:14:21.000 --> 00:14:23.759 told as he put a stick in the ground. But we 00:14:23.759 --> 00:14:26.639 need to unpack the genius of the experiment because 00:14:26.639 --> 00:14:28.899 it's a master class in geometry and observation. 00:14:29.360 --> 00:14:32.409 He used the sun as a protractor. Basically. He 00:14:32.409 --> 00:14:34.730 heard a report, or read it in a scroll in a library, 00:14:34.990 --> 00:14:37.970 that in the city of Syene, which is modern Aswan, 00:14:38.110 --> 00:14:41.049 on the summer solstice at noon, the sun was directly 00:14:41.049 --> 00:14:43.190 overhead. And how did they know that? Because 00:14:43.190 --> 00:14:45.610 there was a deep well. And at that specific moment, 00:14:45.769 --> 00:14:48.250 the sun shone all the way to the bottom. It illuminated 00:14:48.250 --> 00:14:50.590 the water. There was no shadow cast by the rim 00:14:50.590 --> 00:14:52.730 of the well. So the sun is 90 degrees straight 00:14:52.730 --> 00:14:55.230 up, perpendicular to the ground. Right. But in 00:14:55.230 --> 00:14:57.450 Alexandria, which was almost directly north of 00:14:57.450 --> 00:15:00.289 Syene, on the same day at the same time, a stick 00:15:00.289 --> 00:15:02.850 in the ground did cast a shadow. Eratosthenes 00:15:02.850 --> 00:15:05.090 measured the angle of that shadow. It was about 00:15:05.090 --> 00:15:08.210 7 .2 degrees. Okay, so we have 0 degrees in Syene 00:15:08.210 --> 00:15:10.590 and 7 .2 degrees in Alexandria. What does that 00:15:10.590 --> 00:15:14.289 tell us? Here is the geometry. Eratosthenes made 00:15:14.289 --> 00:15:17.830 two assumptions. One, that the sun was so far 00:15:17.830 --> 00:15:20.110 away that its light rays are hitting the earth, 00:15:20.230 --> 00:15:22.210 essentially parallel to each other. Which is 00:15:22.210 --> 00:15:24.830 a good assumption. And two, that the earth is 00:15:24.830 --> 00:15:28.049 a sphere. If the earth was flat, the parallel 00:15:28.049 --> 00:15:30.169 rays would hit both cities at the same angle. 00:15:30.559 --> 00:15:33.419 Both sticks would have no shadow. The only reason 00:15:33.419 --> 00:15:35.360 for the difference in shadow length is if the 00:15:35.360 --> 00:15:37.460 surface of the Earth is curving between the two 00:15:37.460 --> 00:15:40.360 cities. So the 7 .2 degrees represents the amount 00:15:40.360 --> 00:15:42.519 of curvature of the Earth between those two points. 00:15:42.679 --> 00:15:46.039 Exactly. He realized that 7 .2 degrees is 150th 00:15:46.039 --> 00:15:49.059 of a full circle, which is 360 degrees. So, if 00:15:49.059 --> 00:15:51.440 that's the case, the distance between Alexandria 00:15:51.440 --> 00:15:54.519 and Syene must be 150th of the Earth's total 00:15:54.519 --> 00:15:56.559 circumference. Now he just needs to know the 00:15:56.559 --> 00:15:58.360 distance between the cities. He didn't have Google 00:15:58.360 --> 00:16:00.820 Maps. How do you measure a distance of, what 00:16:00.820 --> 00:16:05.169 was it, 500 miles? in 240 BC. You hire a professional? 00:16:05.289 --> 00:16:07.549 They were called bimetists. Bimetists. Professional 00:16:07.549 --> 00:16:10.250 pacers. Walkers. Their entire job was to walk 00:16:10.250 --> 00:16:12.870 long distances with a perfectly consistent stride 00:16:12.870 --> 00:16:15.009 length and count every single step. They were 00:16:15.009 --> 00:16:17.370 human odometers. Can you imagine the pressure 00:16:17.370 --> 00:16:22.230 on that guy? 1 ,001, 1 ,002. Hey, don't talk 00:16:22.230 --> 00:16:23.490 to me. I'll lose camera. Might have to start 00:16:23.490 --> 00:16:26.350 over in Alexandria. It sounds absurd, but they 00:16:26.350 --> 00:16:28.769 were surprisingly accurate. They determined the 00:16:28.769 --> 00:16:31.590 distance was about 5 ,000 stadia. And a stadia 00:16:31.590 --> 00:16:34.570 is? It's an ancient unit, and we're not 100 % 00:16:34.570 --> 00:16:36.570 sure of its exact length, which is why there's 00:16:36.570 --> 00:16:40.230 some debate over his final number. But based 00:16:40.230 --> 00:16:42.830 on the most likely conversion, he did the math. 00:16:43.259 --> 00:16:47.480 5 ,000 times 50 is 250 ,000 stadia. That comes 00:16:47.480 --> 00:16:50.159 out to roughly 40 ,000 kilometers. Which is... 00:16:50.159 --> 00:16:52.919 Almost exactly the real number. He was within 00:16:52.919 --> 00:16:55.639 1 or 2 % of the actual polar circumference of 00:16:55.639 --> 00:16:58.679 the Earth. With a stick, a well, and a guy walking, 00:16:58.879 --> 00:17:01.000 it's one of the greatest scientific experiments 00:17:01.000 --> 00:17:03.549 in history. That is mind -blowing, but... And 00:17:03.549 --> 00:17:05.250 there's always a but in this story. Not everyone 00:17:05.250 --> 00:17:07.150 was convinced. We have to talk about the holdouts. 00:17:07.470 --> 00:17:09.210 Because even in the ancient world, there were 00:17:09.210 --> 00:17:11.849 skeptics. Lucretius is the most famous one. He 00:17:11.849 --> 00:17:13.609 was a Roman poet and philosopher in the first 00:17:13.609 --> 00:17:16.309 century BC. He followed the atomist school of 00:17:16.309 --> 00:17:18.650 thought, like Democritus. Why did he hate the 00:17:18.650 --> 00:17:21.549 sphere? What was his beef with it? It was philosophical, 00:17:21.809 --> 00:17:24.829 not observational. He believed the universe was 00:17:24.829 --> 00:17:28.049 infinite. If the universe is infinite, it can't 00:17:28.049 --> 00:17:31.150 have a center. The Aristotelian model relied 00:17:31.150 --> 00:17:32.849 on the Earth being the center of the universe 00:17:32.849 --> 00:17:35.509 where all heavy things naturally fall. Right. 00:17:35.549 --> 00:17:39.089 Down meant toward the center of the Earth. Lucretius 00:17:39.089 --> 00:17:41.529 said if there is no center, why would things 00:17:41.529 --> 00:17:44.269 fall to a ball? Why wouldn't they just fall down? 00:17:44.650 --> 00:17:47.529 He believed in a universal down. Ah, the universal 00:17:47.529 --> 00:17:51.349 down idea. A single direction for the whole infinite 00:17:51.349 --> 00:17:54.529 cosmos. Right. And this led him to mock the idea 00:17:54.529 --> 00:17:57.859 of. The antipodes. You antipodes. We need to 00:17:57.859 --> 00:17:59.779 define this word because it keeps coming up in 00:17:59.779 --> 00:18:03.599 the sources. Anti -opposite -podes. Feet? Yeah. 00:18:03.700 --> 00:18:05.779 People whose feet are opposite yours. The people 00:18:05.779 --> 00:18:07.900 on the other side of the globe. Lucretius thought 00:18:07.900 --> 00:18:10.019 this was a comedy routine. He wrote that the 00:18:10.019 --> 00:18:12.299 idea of men walking upside down or rain falling 00:18:12.299 --> 00:18:13.980 upwards into the sky on the other side of the 00:18:13.980 --> 00:18:16.539 world was absurd. He basically said, look, have 00:18:16.539 --> 00:18:19.279 you ever seen anything fall up? No. So why would 00:18:19.279 --> 00:18:21.480 people stick to the bottom of a ball? It's intuitive 00:18:21.480 --> 00:18:23.779 again. Without a theory of gravity, the idea 00:18:23.779 --> 00:18:26.740 that mass attracts mass, the sphere does seem 00:18:26.740 --> 00:18:28.799 ridiculous. Why doesn't the water drain off the 00:18:28.799 --> 00:18:30.660 bottom? Why don't people in Australia just fall 00:18:30.660 --> 00:18:34.460 off? Exactly. But despite Lucretius, the consensus 00:18:34.460 --> 00:18:37.680 held. By the time of the Roman Empire, Pliny 00:18:37.680 --> 00:18:40.720 the Elder writes in his encyclopedia that everyone 00:18:40.720 --> 00:18:44.099 agrees on the spherical shape. It was settled 00:18:44.099 --> 00:18:46.359 science in the West. They still argued about 00:18:46.359 --> 00:18:49.299 the antipodes, but the shape was a given. In 00:18:49.299 --> 00:18:52.019 the West. But if we pan the camera across the 00:18:52.019 --> 00:18:55.539 Silk Road to China, we enter a completely different 00:18:55.539 --> 00:18:58.380 reality, a parallel intellectual universe. The 00:18:58.380 --> 00:19:00.700 Chinese exception. This is a part of the history 00:19:00.700 --> 00:19:03.299 that often gets skipped, but it's crucial. China 00:19:03.299 --> 00:19:05.619 had a civilization just as advanced, if not more 00:19:05.619 --> 00:19:08.059 so, than Rome. They had brilliant engineers, 00:19:08.400 --> 00:19:11.059 astronomers who cataloged comets, mathematicians 00:19:11.059 --> 00:19:13.640 who calculated pi. But they operated on a flat 00:19:13.640 --> 00:19:16.359 earth model almost until the 17th century. How 00:19:16.359 --> 00:19:18.740 is that possible? How do you map the stars effectively 00:19:18.740 --> 00:19:21.220 if you have the wrong shape of the ground? Well, 00:19:21.240 --> 00:19:23.420 their model was called Gaitian, the canopy heavens. 00:19:23.680 --> 00:19:25.940 And the standard phrase was, the sky is round, 00:19:26.099 --> 00:19:28.759 the earth is square. A square earth, not even 00:19:28.759 --> 00:19:31.079 a circle. Yes, think of a chessboard. And over 00:19:31.079 --> 00:19:33.059 the chessboard, you have a round canopy or an 00:19:33.059 --> 00:19:35.079 umbrella that rotates. That was the heavens. 00:19:35.380 --> 00:19:39.200 It was a deeply ingrained philosophical and cosmological 00:19:39.200 --> 00:19:42.000 view. But I recall reading about an egg analogy. 00:19:42.500 --> 00:19:45.440 Zhang Heng, a brilliant polymath in the Han Dynasty, 00:19:45.680 --> 00:19:48.299 described the universe as a hen's egg. That sounds 00:19:48.299 --> 00:19:50.559 pretty spherical. This is where translation and 00:19:50.559 --> 00:19:52.799 interpretation get tricky. In the 20th century, 00:19:52.980 --> 00:19:55.920 Western historians like Joseph Needham read Zhang 00:19:55.920 --> 00:19:59.279 Heng's text. And Zhang wrote, the heavens are 00:19:59.279 --> 00:20:02.160 like a hen's egg. The earth is like the yolk 00:20:02.160 --> 00:20:04.740 of the egg and lies in the center. Okay, yolk 00:20:04.740 --> 00:20:07.380 equals round. Case closed, right? That sounds 00:20:07.380 --> 00:20:08.740 like he got it. That's what Needham thought. 00:20:09.079 --> 00:20:11.200 He argued that the Chinese knew it was a sphere, 00:20:11.400 --> 00:20:13.680 but later scholars looked closer at the context 00:20:13.680 --> 00:20:16.460 and at Zhang Heng's other writings. In another 00:20:16.460 --> 00:20:19.640 text, Zhang Heng himself wrote, Earth takes its 00:20:19.640 --> 00:20:22.640 body from the yin, so it is flat and quiescent. 00:20:22.759 --> 00:20:25.619 Flat and quiescent. So the egg analogy was about 00:20:25.619 --> 00:20:30.519 what? Position. Position. Nesting. He meant the 00:20:30.519 --> 00:20:32.740 earth is inside the heavens, fully enclosed, 00:20:33.039 --> 00:20:35.819 like a yolk is inside an egg. But not that it 00:20:35.819 --> 00:20:38.359 was a sphere. The yolk can be flat inside the 00:20:38.359 --> 00:20:41.210 shell. Ah, so it was about being enclosed, not 00:20:41.210 --> 00:20:44.730 about being spherical. Precisely. And this philosophical 00:20:44.730 --> 00:20:47.849 commitment to the square Earth had real consequences 00:20:47.849 --> 00:20:50.910 for their science. There's a story about how 00:20:50.910 --> 00:20:53.190 they tried to do an Eratosthenes -style measurement, 00:20:53.289 --> 00:20:55.529 but it went completely wrong. This is fascinating. 00:20:55.789 --> 00:20:58.589 What happened? This is a perfect example of how 00:20:58.589 --> 00:21:01.789 your starting axiom dictates your results. In 00:21:01.789 --> 00:21:04.990 the Tang Dynasty, around 7 and 20 AD, a monk 00:21:04.990 --> 00:21:08.190 and astronomer named Yi Jing led a massive imperial 00:21:08.190 --> 00:21:11.470 survey. They measured the shadow of the sun at 00:21:11.470 --> 00:21:13.470 different latitudes, just like Eratosthenes. 00:21:13.890 --> 00:21:15.630 They had better instruments than the Greeks. 00:21:15.710 --> 00:21:18.069 Their data was incredibly precise. But they started 00:21:18.069 --> 00:21:19.769 with the assumption that the Earth was flat. 00:21:19.950 --> 00:21:22.250 Right. So when they saw the shadow length change 00:21:22.250 --> 00:21:25.170 as they moved north, they didn't think, the Earth 00:21:25.170 --> 00:21:27.609 is curving away from the sun's rays. They thought, 00:21:27.710 --> 00:21:29.670 the sun must be much closer than we thought. 00:21:29.970 --> 00:21:33.029 Ooh. Because if the Earth is flat and the shadow 00:21:33.029 --> 00:21:35.109 gets shorter, it means you're getting closer 00:21:35.109 --> 00:21:37.450 to the light source. Like walking under a street 00:21:37.450 --> 00:21:39.910 lamp, the shadow changes. Exactly. So they used 00:21:39.910 --> 00:21:42.529 trigonometry, assuming a flat Earth, to calculate 00:21:42.529 --> 00:21:44.849 the height of the sun. They calculated that the 00:21:44.849 --> 00:21:48.009 sun was exactly 100 ,000 light, which is about 00:21:48.009 --> 00:21:51.089 200 ,000 kilometers above the ground. So they 00:21:51.089 --> 00:21:53.289 did the math perfectly. They gathered the data 00:21:53.289 --> 00:21:56.150 perfectly. But because their foundational belief 00:21:56.150 --> 00:21:59.069 was Earth is flat, they ended up with a tiny, 00:21:59.150 --> 00:22:02.609 close sun. instead of around Earth. It wasn't 00:22:02.609 --> 00:22:05.789 until the Jesuits arrived in the 1600s, specifically 00:22:05.789 --> 00:22:08.769 Matteo Ricci, bringing European globes and maps 00:22:08.769 --> 00:22:11.230 and astronomical knowledge, that the Chinese 00:22:11.230 --> 00:22:13.349 court finally began to shift toward the spherical 00:22:13.349 --> 00:22:16.109 view. It shows that intelligence isn't the same 00:22:16.109 --> 00:22:18.390 as correctness. You can be a genius and still 00:22:18.390 --> 00:22:20.390 be wrong if your starting premise is flawed. 00:22:20.589 --> 00:22:23.130 That is a lesson for the ages. Okay, let's jump 00:22:23.130 --> 00:22:24.549 back to Europe. We need to tackle the elephant 00:22:24.549 --> 00:22:27.220 in the room. the myth of the dark ages the columbus 00:22:27.220 --> 00:22:30.660 myth we were all told the story the brave handsome 00:22:30.660 --> 00:22:33.380 christopher columbus stands before the ignorant 00:22:33.380 --> 00:22:36.559 spanish court the priests are wagging their fingers 00:22:36.559 --> 00:22:39.559 saying you can't sail west you'll fall off the 00:22:39.559 --> 00:22:42.380 edge the monsters will eat you and columbus says 00:22:42.380 --> 00:22:45.640 no science says it is round it is a dramatic 00:22:45.640 --> 00:22:49.019 scene it's heroic It's got conflict and it is 00:22:49.019 --> 00:22:52.519 100 % fiction. It never happened. Not one bit 00:22:52.519 --> 00:22:55.240 of it. Never. The debate between Columbus and 00:22:55.240 --> 00:22:57.000 the Spanish Royal Commission, which actually 00:22:57.000 --> 00:22:59.160 happened, was not about the shape of the earth. 00:22:59.240 --> 00:23:01.619 It was about the size. Everyone in the room knew 00:23:01.619 --> 00:23:03.789 it was a sphere. They were arguing about the 00:23:03.789 --> 00:23:06.809 circumference. Yes. The Royal Commission, which 00:23:06.809 --> 00:23:09.670 was made up of educated men, used Eratosthenes' 00:23:09.769 --> 00:23:12.529 old numbers. They said the Earth is about 40 00:23:12.529 --> 00:23:15.430 ,000 kilometers around. The ocean between Europe 00:23:15.430 --> 00:23:17.829 and Asia is too big. You will run out of food 00:23:17.829 --> 00:23:20.069 and water before you get to Japan. And Columbus 00:23:20.069 --> 00:23:23.069 said. Columbus essentially cherry -picked bad 00:23:23.069 --> 00:23:26.430 math. He used calculations from a Persian geographer, 00:23:26.569 --> 00:23:29.490 but mixed up the units of measurement using Roman 00:23:29.490 --> 00:23:32.250 miles instead of Arabic miles, which were longer. 00:23:32.539 --> 00:23:35.980 He also underestimated the size of Asia. He basically 00:23:35.980 --> 00:23:38.039 fudged the numbers to convince himself the Earth 00:23:38.039 --> 00:23:41.099 was much smaller, about 25 ,000 kilometers around. 00:23:41.380 --> 00:23:44.880 So Columbus was the bad mathematician. The ignorant 00:23:44.880 --> 00:23:47.559 priests were actually right. The priests and 00:23:47.559 --> 00:23:49.779 scholars were scientifically correct. The ocean 00:23:49.779 --> 00:23:52.839 was too big. If the Americas hadn't been there, 00:23:52.940 --> 00:23:54.880 which neither side knew about, Columbus and his 00:23:54.880 --> 00:23:56.319 crew would have died of thirst in the middle 00:23:56.319 --> 00:23:58.890 of the Atlantic. He got lucky. So if everyone 00:23:58.890 --> 00:24:01.049 knew it was round, where did this story come 00:24:01.049 --> 00:24:03.150 from? Why does every American school child know 00:24:03.150 --> 00:24:05.589 the people thought it was flat story? We have 00:24:05.589 --> 00:24:07.710 to blame the storyteller, Washington Irving. 00:24:07.789 --> 00:24:09.509 The guy who wrote The Legend of Sleepy Hollow. 00:24:09.890 --> 00:24:12.789 The Headless Horseman guy. The very same. In 00:24:12.789 --> 00:24:15.589 1828, he wrote a biography called A History of 00:24:15.589 --> 00:24:17.329 the Life and Voyages of Christopher Columbus. 00:24:17.569 --> 00:24:19.369 It was more historical fiction than history. 00:24:19.509 --> 00:24:21.470 He wanted to write a bestseller. He wanted a 00:24:21.470 --> 00:24:24.599 hero. And a hero needs a villain. And a bureaucratic 00:24:24.599 --> 00:24:27.299 argument about the length of a sea mile isn't 00:24:27.299 --> 00:24:30.619 a very sexy villain. Exactly. So Irving, being 00:24:30.619 --> 00:24:33.259 a fiction writer at heart, invented the scene 00:24:33.259 --> 00:24:36.460 of the ignorant flat earth priests. He framed 00:24:36.460 --> 00:24:39.319 Columbus as the lone beacon of science against 00:24:39.319 --> 00:24:41.920 the darkness of religious stupidity. He just 00:24:41.920 --> 00:24:44.039 made it up for dramatic effect. And people just 00:24:44.039 --> 00:24:46.519 thought it. They loved it. It was a great story. 00:24:46.700 --> 00:24:49.619 But it wasn't just Irving. Later in the 19th 00:24:49.619 --> 00:24:52.140 century, you had scholars like John William Draper 00:24:52.140 --> 00:24:54.680 and Andrew Dixon White. They were pushing something 00:24:54.680 --> 00:24:57.680 called the conflict thesis. What is that? The 00:24:57.680 --> 00:24:59.559 idea that science and religion are fundamentally 00:24:59.559 --> 00:25:02.579 and eternally at war. They wanted to show that 00:25:02.579 --> 00:25:05.099 the church has always held back progress. So 00:25:05.099 --> 00:25:07.660 they latched onto Irving's story and presented 00:25:07.660 --> 00:25:10.630 it as historical fact. They effectively slandered 00:25:10.630 --> 00:25:13.250 a thousand years of medieval scholarship to score 00:25:13.250 --> 00:25:15.970 a political point in the 1870s. Because the reality 00:25:15.970 --> 00:25:18.210 of the Middle Ages was very different. Completely 00:25:18.210 --> 00:25:20.549 different. If you go to a university in 1250 00:25:20.549 --> 00:25:24.430 AD, the standard astronomy textbook was Desiramundi 00:25:24.430 --> 00:25:27.150 on the Sphere of the World by John of Sacrobosco. 00:25:27.269 --> 00:25:29.309 It's in the title. It's right there in the title. 00:25:29.609 --> 00:25:31.930 Thomas Aquinas, the greatest theologian of the 00:25:31.930 --> 00:25:35.490 era, starts his Summa Theologica by using the 00:25:35.490 --> 00:25:38.109 spherical Earth as an example of a fact that 00:25:38.109 --> 00:25:40.769 is proven by physics. He treats it as obvious, 00:25:40.809 --> 00:25:43.650 like, of course the Earth is round, just as it's 00:25:43.650 --> 00:25:46.170 obvious that. And you mentioned the kings, the 00:25:46.170 --> 00:25:49.289 symbols they held. The Globus Cruciger. You've 00:25:49.289 --> 00:25:52.109 seen it in paintings of Queen Elizabeth or Charlemagne. 00:25:52.390 --> 00:25:55.930 They hold a golden orb with a cross on top. The 00:25:55.930 --> 00:25:58.240 Holy Hand Grenade. Right. That orb represents 00:25:58.240 --> 00:26:01.079 the universe, the earth. The cross represents 00:26:01.079 --> 00:26:03.720 Christ's dominion over it. If they thought the 00:26:03.720 --> 00:26:05.259 world was flat, they would have held a plate 00:26:05.259 --> 00:26:07.819 or a disc. The fact that the ultimate symbol 00:26:07.819 --> 00:26:10.519 of power was a sphere tells you everything you 00:26:10.519 --> 00:26:12.819 need to know about the medieval worldview. Okay, 00:26:12.880 --> 00:26:15.000 so they knew it was round, but was there any 00:26:15.000 --> 00:26:18.099 debate or was it total consensus? There was a 00:26:18.099 --> 00:26:19.900 debate, but it goes back to the Antipodes. It 00:26:19.900 --> 00:26:22.160 goes back to St. Augustine. Augustine of Hippo, 00:26:22.400 --> 00:26:25.539 4th century, one of the most influential church 00:26:25.539 --> 00:26:28.799 fathers. Augustine was a smart guy. He read the 00:26:28.799 --> 00:26:31.420 science of his day. He accepted the spherical 00:26:31.420 --> 00:26:34.720 shape. But he had a theological problem with 00:26:34.720 --> 00:26:36.940 the other side of the world. He argued that there 00:26:36.940 --> 00:26:39.000 could not be people there. Walk us through the 00:26:39.000 --> 00:26:41.799 logic. Why not? It was a syllogism. Premise 1. 00:26:42.039 --> 00:26:45.039 All humans are descended from Adam and Eve. Premise 00:26:45.039 --> 00:26:48.240 2. The equatorial ocean is a scorching hot boiling 00:26:48.240 --> 00:26:52.339 sea, the torrid zone. No ship can possibly cross 00:26:52.339 --> 00:26:55.700 it. Conclusion. If no ship can cross it, Adam's 00:26:55.700 --> 00:26:57.299 descendants could never have reached the other 00:26:57.299 --> 00:27:00.339 side. Therefore, the other side is empty. It 00:27:00.339 --> 00:27:03.019 might be land, but it is uninhabited by humans. 00:27:03.220 --> 00:27:05.660 So the debate wasn't, is it flat? It was, is 00:27:05.660 --> 00:27:08.740 the other side empty? Exactly. And this brings 00:27:08.740 --> 00:27:10.619 us to the one guy the myth makers always point 00:27:10.619 --> 00:27:13.839 to, Cosmas Inacoploustes. Cosmas, who sailed 00:27:13.839 --> 00:27:16.660 to India. Quite a name. He was a 6th century 00:27:16.660 --> 00:27:19.470 merchant turned monk. And he did write a book 00:27:19.470 --> 00:27:22.210 arguing the earth was flat. He drew it as a rectangle, 00:27:22.470 --> 00:27:24.569 shaped like the tabernacle of Moses from the 00:27:24.569 --> 00:27:26.690 Old Testament. So there was one. The myth has 00:27:26.690 --> 00:27:30.049 a grain of truth. There was one. But he was the 00:27:30.049 --> 00:27:32.809 exception that proves the rule. His contemporaries 00:27:32.809 --> 00:27:35.549 mocked him. Another Christian philosopher, John 00:27:35.549 --> 00:27:38.009 Philipponus, wrote a scathing rebuttal telling 00:27:38.009 --> 00:27:40.269 him he was an idiot and that he was making Christians 00:27:40.269 --> 00:27:43.769 look bad by ignoring basic astronomy. Cosmas 00:27:43.769 --> 00:27:46.730 was a fringe blogger in his own time. But modern 00:27:46.730 --> 00:27:49.490 historians or pseudo historians picked him out 00:27:49.490 --> 00:27:52.190 of the trash heap and said, look, this represents 00:27:52.190 --> 00:27:55.150 the entire Middle Ages. It's classic cherry picking. 00:27:55.289 --> 00:27:57.390 It's like looking at a flat earth tweet from 00:27:57.390 --> 00:28:00.569 2024 and saying the people of the 21st century 00:28:00.569 --> 00:28:03.190 believe the earth was flat. Which, ironically, 00:28:03.349 --> 00:28:05.609 brings us to the 21st century because people 00:28:05.609 --> 00:28:07.970 do believe it again. The modern resurgence. This 00:28:07.970 --> 00:28:09.910 is the part of the deep dive that shifts from 00:28:09.910 --> 00:28:14.319 history to sociology and. psychology. When did 00:28:14.319 --> 00:28:16.700 it come back? Because for a long time, Flat Earth 00:28:16.700 --> 00:28:19.059 Society was a punchline. It was a joke about 00:28:19.059 --> 00:28:21.640 people who argue for the sake of arguing. The 00:28:21.640 --> 00:28:24.059 modern movement starts, weirdly enough, in the 00:28:24.059 --> 00:28:26.920 19th century. Just as the myth of the Flat Earth 00:28:26.920 --> 00:28:29.980 Pass was being invented, a guy named Samuel Rowbotham 00:28:29.980 --> 00:28:32.099 started actually preaching it. What was his deal? 00:28:32.359 --> 00:28:35.420 He was an English inventor and writer. In 1849, 00:28:35.640 --> 00:28:38.500 he published a pamphlet under the pseudonym Parallax 00:28:38.500 --> 00:28:42.470 called Zetetic Astronomy. Earth. Not a globe. 00:28:42.890 --> 00:28:44.849 Zetatic. That's a key word here. What does it 00:28:44.849 --> 00:28:47.150 mean? It comes from the Greek zetio, meaning 00:28:47.150 --> 00:28:50.529 to seek or to inquire. Robotham's philosophy 00:28:50.529 --> 00:28:53.950 was, do not trust theories. Do not trust what 00:28:53.950 --> 00:28:56.690 you are told by so -called experts. Trust only 00:28:56.690 --> 00:28:58.589 what you can demonstrate with your own senses. 00:28:58.829 --> 00:29:01.029 Back to the floating log. Back to the intuitive 00:29:01.029 --> 00:29:04.609 view. It all comes full circle. Exactly. He argued 00:29:04.609 --> 00:29:06.609 that if you look at a canal, specifically the 00:29:06.609 --> 00:29:08.710 old Bedford -level canal, which is a long, straight 00:29:08.710 --> 00:29:11.809 drainage canal, the water looks flat for six 00:29:11.809 --> 00:29:14.809 miles. Therefore, the world is flat. He was a 00:29:14.809 --> 00:29:16.930 master showman. He would hold public debates, 00:29:17.130 --> 00:29:19.549 shout down astronomers, and he gained a small 00:29:19.549 --> 00:29:22.349 but dedicated following. This evolved into the 00:29:22.349 --> 00:29:25.049 Universal Zetetic Society, but it stayed pretty 00:29:25.049 --> 00:29:27.130 small, right? A handful of people. It was a fringe 00:29:27.130 --> 00:29:29.390 curiosity. The Flat Earth Society was founded 00:29:29.390 --> 00:29:32.089 in 1956, but it never had more than a few thousand 00:29:32.089 --> 00:29:34.910 members. It was a quirk. Until around 2015. The 00:29:34.910 --> 00:29:37.450 algorithm era. We cannot overstate the role of 00:29:37.450 --> 00:29:39.849 YouTube and social media algorithms in this. 00:29:40.250 --> 00:29:43.470 Around 2015, the recommendation engines figured 00:29:43.470 --> 00:29:46.789 out that Flat Earth videos were sticky. Sticky 00:29:46.789 --> 00:29:48.690 meaning people watched them all the way through. 00:29:48.869 --> 00:29:51.900 And commented. And shared. They generated massive 00:29:51.900 --> 00:29:55.240 engagement. So the algorithm pushed them to millions 00:29:55.240 --> 00:29:57.839 of people. People watch conspiracy video about 00:29:57.839 --> 00:30:01.319 9 -11 and the up next would be 200 proofs Earth 00:30:01.319 --> 00:30:03.819 is not a spinning ball. And it sends them down 00:30:03.819 --> 00:30:05.759 the rabbit hole. A very deep one. We have to 00:30:05.759 --> 00:30:07.579 get into the psychology of the modern believer 00:30:07.579 --> 00:30:10.839 because unlike the Babylonians, these people 00:30:10.839 --> 00:30:12.900 have access to Google Earth. They can book a 00:30:12.900 --> 00:30:16.619 flight from Sydney to Santiago. How do they maintain 00:30:16.619 --> 00:30:19.380 the belief? in the face of just overwhelming 00:30:19.380 --> 00:30:21.740 evidence. It requires a massive psychological 00:30:21.740 --> 00:30:24.259 firewall. We call it the conspiracy necessity. 00:30:24.640 --> 00:30:26.279 Meaning? Meaning you cannot believe the earth 00:30:26.279 --> 00:30:29.859 is flat in 2026 without also believing in a massive, 00:30:29.960 --> 00:30:33.240 coordinated, global conspiracy to hide the truth. 00:30:33.480 --> 00:30:36.289 It's a package deal. It has to be. You have to 00:30:36.289 --> 00:30:38.849 believe NASA is fake. You have to believe all 00:30:38.849 --> 00:30:41.990 space agencies, Russian, Chinese, Indian, are 00:30:41.990 --> 00:30:44.730 working together to lie to us. You have to believe 00:30:44.730 --> 00:30:47.930 every pilot is in on it, every GPS engineer, 00:30:48.170 --> 00:30:51.470 every satellite TV technician. It creates a villain 00:30:51.470 --> 00:30:54.190 again. They are lying to us. And that is the 00:30:54.190 --> 00:30:57.250 appeal. It makes the believer feel special. I 00:30:57.250 --> 00:31:00.190 am not a sheep. I know the truth. I have woken 00:31:00.190 --> 00:31:03.460 up. It appeals to people who feel disenfranchised, 00:31:03.519 --> 00:31:05.759 who don't trust the government, who feel like 00:31:05.759 --> 00:31:07.960 the world is out of control. This is one thing 00:31:07.960 --> 00:31:09.859 they feel they can understand and control. Let's 00:31:09.859 --> 00:31:12.000 talk about their model, because they don't believe 00:31:12.000 --> 00:31:14.059 in the edge where you fall off into space, right? 00:31:14.240 --> 00:31:16.640 Generally, no. Most modern flat earthers believe 00:31:16.640 --> 00:31:19.240 in the ice wall. Which is Antarctica. In their 00:31:19.240 --> 00:31:21.579 map, which is usually just the UN flag logo, 00:31:21.759 --> 00:31:24.680 and as a beautiful equidistant projection, the 00:31:24.680 --> 00:31:27.680 North Pole is in the center. The continents spread 00:31:27.680 --> 00:31:30.079 out from there. And Antarctica isn't a continent 00:31:30.079 --> 00:31:32.700 at the bottom. It is a giant ring of ice that 00:31:32.700 --> 00:31:35.099 surrounds the entire disk. Like a pizza crust 00:31:35.099 --> 00:31:37.980 holding in the sauce. Exactly. And the theory 00:31:37.980 --> 00:31:40.579 is that if you try to go there, the military 00:31:40.579 --> 00:31:43.140 will stop you. The Antarctic Treaty is viewed 00:31:43.140 --> 00:31:45.900 by them not as an environmental agreement, but 00:31:45.900 --> 00:31:48.779 as a militarized border pact to keep people away 00:31:48.779 --> 00:31:50.799 from the edge of the dome or the edge of the 00:31:50.799 --> 00:31:53.299 world. It effectively makes the world a prison. 00:31:53.980 --> 00:31:56.759 Or a terrarium with a giant ice wall. And that 00:31:56.759 --> 00:31:59.240 leads to the do -it -yourself science. You see 00:31:59.240 --> 00:32:01.579 these guys buying $10 ,000 gyroscopes or taking 00:32:01.579 --> 00:32:05.119 high -powered cameras. The Nikon P900 is famous 00:32:05.119 --> 00:32:07.359 in this community to the beach to try and zoom 00:32:07.359 --> 00:32:10.240 in and bring ships back over the horizon. There 00:32:10.240 --> 00:32:12.640 is a tragedy in that. They are curious. They 00:32:12.640 --> 00:32:14.319 are buying equipment. They are experimenting. 00:32:14.420 --> 00:32:16.640 They are acting like scientists. But they refuse 00:32:16.640 --> 00:32:19.460 to accept any result that contradicts their belief. 00:32:19.740 --> 00:32:21.480 There is a famous scene in the documentary Behind 00:32:21.480 --> 00:32:23.740 the Curve, which I highly recommend, where a 00:32:23.740 --> 00:32:25.700 group of flat earthers sets up an experiment 00:32:25.700 --> 00:32:29.269 with lasers and posts over a canal. to prove 00:32:29.269 --> 00:32:31.650 the water is flat the bedford level experiment 00:32:31.650 --> 00:32:34.930 updated yep and the experiment proves the water 00:32:34.930 --> 00:32:37.470 is curved their own experiment and instead of 00:32:37.470 --> 00:32:39.710 saying oh wow i guess we were wrong one of them 00:32:39.710 --> 00:32:42.069 says that's interesting and another says they 00:32:42.069 --> 00:32:44.809 encountered heaven energies that must have bent 00:32:44.809 --> 00:32:47.329 the laser that is the difference between science 00:32:47.329 --> 00:32:50.029 and pseudoscience right there science changes 00:32:50.029 --> 00:32:52.710 the theory to fit the data pseudoscience changes 00:32:52.710 --> 00:32:56.119 the data to fit the theory or Just ignores it. 00:32:56.240 --> 00:32:58.779 Precisely. And while the number of hardcore believers 00:32:58.779 --> 00:33:01.480 is small, maybe one or two percent, the sentiment 00:33:01.480 --> 00:33:04.859 is growing. A 2018 survey showed that only 82 00:33:04.859 --> 00:33:07.380 percent of 18 to 24 year olds in the U .S. firmly 00:33:07.380 --> 00:33:10.519 agreed. I have always believed the world is round. 00:33:10.660 --> 00:33:13.559 Only 82 percent. That number should be 100 percent. 00:33:13.960 --> 00:33:16.119 It's not that the other 18 % are committed flat 00:33:16.119 --> 00:33:18.500 earthers. It's that they are skeptical. They've 00:33:18.500 --> 00:33:20.059 been exposed to the counter -narrative online, 00:33:20.240 --> 00:33:22.220 and now they're thinking, well, maybe. I'm just 00:33:22.220 --> 00:33:24.740 asking questions. That phrase is the gateway 00:33:24.740 --> 00:33:27.880 drug. It reflects a breakdown in trust. We don't 00:33:27.880 --> 00:33:30.180 trust experts anymore. We don't trust institutions. 00:33:30.519 --> 00:33:32.460 And if you don't trust anyone, you fall back 00:33:32.460 --> 00:33:34.539 on your own eyes. And your eyes tell you the 00:33:34.539 --> 00:33:37.160 world is flat. This has real consequences for 00:33:37.160 --> 00:33:39.380 education. I can't imagine being a science teacher 00:33:39.380 --> 00:33:42.190 today. It's a battleground. Child psychologists 00:33:42.190 --> 00:33:44.769 tell us that kids naturally develop a flat earth 00:33:44.769 --> 00:33:48.109 model. It's intuitive. A small child's universe 00:33:48.109 --> 00:33:51.210 is flat with a sky above it. Education is the 00:33:51.210 --> 00:33:54.390 process of unlearning that intuition and replacing 00:33:54.390 --> 00:33:57.210 it with a complex, non -intuitive model based 00:33:57.210 --> 00:34:00.160 on data. But now teachers aren't just fighting 00:34:00.160 --> 00:34:02.140 a child's natural intuition. They're fighting 00:34:02.140 --> 00:34:04.319 TikTok. The National Center for Science Education 00:34:04.319 --> 00:34:07.059 actually provides resources now specifically 00:34:07.059 --> 00:34:09.860 for this. Teachers have students coming in saying, 00:34:10.000 --> 00:34:12.800 but I saw a video that says gravity is just buoyancy 00:34:12.800 --> 00:34:15.679 and density. The teacher has to deconstruct the 00:34:15.679 --> 00:34:17.639 algorithm's programming before they can teach 00:34:17.639 --> 00:34:20.179 the physics. It's a heavy lift, a very heavy 00:34:20.179 --> 00:34:23.530 lift. It is. So let's try to land this. or the 00:34:23.530 --> 00:34:26.429 spaceship. We've gone from Thales and his log 00:34:26.429 --> 00:34:29.250 to the brilliant geometry of Eratosthenes, to 00:34:29.250 --> 00:34:31.829 the stubborn square of China, to the fake news 00:34:31.829 --> 00:34:34.670 of Washington Irving, and finally to the YouTube 00:34:34.670 --> 00:34:37.090 rabbit hole. It's a long, strange trip through 00:34:37.090 --> 00:34:39.469 the human mind. What is the big takeaway here? 00:34:39.969 --> 00:34:43.250 Why should you, the listener, who presumably 00:34:43.250 --> 00:34:46.489 knows the Earth is round, care about this history? 00:34:46.690 --> 00:34:49.250 I think it's a lesson in humility. The Earth 00:34:49.250 --> 00:34:52.010 has always been round. The physical reality hasn't 00:34:52.010 --> 00:34:55.070 changed. But our perception of it and our ability 00:34:55.070 --> 00:34:57.849 to accept it depends entirely on the tools we 00:34:57.849 --> 00:35:00.469 use and the stories we trust. It's a reminder 00:35:00.469 --> 00:35:02.869 that common sense is often the enemy of truth. 00:35:03.150 --> 00:35:05.590 Common sense says the Earth is flat and stationary. 00:35:06.150 --> 00:35:08.929 Science says we are spinning on a rock at 1 ,000 00:35:08.929 --> 00:35:11.869 miles an hour, orbiting a fusion explosion in 00:35:11.869 --> 00:35:15.170 an expanding universe. The truth is not intuitive. 00:35:15.829 --> 00:35:19.239 It requires work. It requires trust in the collective 00:35:19.239 --> 00:35:21.619 intelligence of humanity built up over thousands 00:35:21.619 --> 00:35:23.980 of years. And it requires us to check our own 00:35:23.980 --> 00:35:26.159 myths. I want to leave you with a thought that 00:35:26.159 --> 00:35:28.000 kind of haunts me after going through all this. 00:35:28.119 --> 00:35:31.000 We look back at the 19th century people who mocked 00:35:31.000 --> 00:35:33.159 the medievals. They invented a fake history, 00:35:33.340 --> 00:35:35.619 the flat earth dark ages, to make themselves 00:35:35.619 --> 00:35:38.780 feel superior and modern. They needed to feel 00:35:38.780 --> 00:35:40.780 like they had conquered ignorance, that they 00:35:40.780 --> 00:35:43.480 were the enlightened ones. Right. So the question 00:35:43.480 --> 00:35:46.829 is, what are we doing right now? What scientific 00:35:46.829 --> 00:35:49.690 truths or historical facts do we accept today 00:35:49.690 --> 00:35:52.610 simply because they make us feel superior to 00:35:52.610 --> 00:35:55.730 the past? What will the people doing these deep 00:35:55.730 --> 00:35:58.329 dives in the year 2500 be laughing at us for 00:35:58.329 --> 00:36:01.110 believing? That is a terrifying question, and 00:36:01.110 --> 00:36:02.969 I don't have the answer. Something to think about 00:36:02.969 --> 00:36:05.070 next time you look at the horizon. Thanks for 00:36:05.070 --> 00:36:07.050 diving deep with us. Keep looking up. See you 00:36:07.050 --> 00:36:07.309 next time.