Dr. Moya McTeer (3:11)

No, academia gives you some good training for head, heart, gut. Actually.

Dr. Claire Aubin (3:15)

Absolutely. Especially if you're the sort of debate club, model UN style person that. I was not an athlete. However, I was, I was, I was arguing as a, as a youth and then I did a law degree. Like it's the whole. Yeah, yeah, built. Built for arguments.

Dr. Moya McTeer (3:33)

No, you did great in head. Hard gut.

Dr. Claire Aubin (3:35)

Thank you. Let's get into what we're really all here for. Rather than telling people about a podcast that they're probably not listening to, but they can if they join the multi crew. Who are we talking about today?

Dr. Moya McTeer (3:49)

Today we are talking about Claudius Ptolemy. The P is not silent, but it is subtle according to, you know, native Greek speakers that I've asked about it. And we don't know many details about his personal life. Like we don't even know when he was born or when exactly he died. But he lived in the second century C.E. and he was, according to some, some. One of the most accomplished ancient astronomers in the world. He gave us the most of the constellations that we still use today. He did a lot of work in cataloging and tracking the motion of stars in the galaxy and trying to figure out the order of our solar system. And that is why I wanted to talk about him today because he is known not as the like, founder of geocentrism, the idea that the Earth is at the center of not just the solar system, but the entire universe. But his model of geocentrism was used by the Catholic Church for 1500 years to squash real scientific advancement and like our, our real understanding of the night sky. So my gripe with Ptolemy is that even though he didn't start it, he became the poster child for geocentrism. And I just can't let that stand.

Dr. Claire Aubin (5:11)

Fair enough. We will get to all of the sort of nitty gritty of the what's wrong with him in just a second. But I think it's also important for people to really. Because I'm. That's the best. That's the point of the show. Like, that's the best part of the show. Really. But I think it's important for people also in order to really understand why this is a problem and why you have a problem with him. It's important for them to get his real sort of contributions or the sort of broader understandings that people might already have, or if they've only heard of him in a textbook or something, why he might be familiar to them. And I want to mention, as always, that this is so extremely not my area of expertise. One ANCIENT two Math and science. So even when I was trying to do research for this episode prep, I was like, I do not fully understand what's happening here, which means I'm flying a little bit blinder than usual.

Dr. Moya McTeer (6:06)

I'm curious where it broke down for you. And I will say that you're not alone because all of the ancient people who were studying Ptolemy after he died, they didn't really understand what he was saying either.

Dr. Claire Aubin (6:17)

Well, I mean, I think once we get to the problems with him, I'll definitely be able to draw out some of the issues that I came across. But really a lot of me trying to do prep for this episode was me saying, so what have other people said about him? Because normally I can figure out where the problems are immediately. Like normally I can research someone or read a book or whatever and from, from the guest and be able to say, okay, this is where the issues are going to be with this one. I know the big, the big one. But it seems like there were a few other critiques that I kind of was like, huh? Because I'm not an astronomer. There's no world in which I would possibly have known that that was a problem.

Dr. Moya McTeer (6:52)

Right, right.

Dr. Claire Aubin (6:54)

So Ptolemy, like you said, also known as Claudius Ptolemy or to born, as you said, around 100 AD?. Died at some point in the 160s to 170s. There are like five or six different years that he allegedly died within there some point in the mid to late 160s, early 170s ish. So yeah, second century, Greco Roman, possibly born in a Greek city in Europe, in Egypt. Not Europe, a Greek city in Egypt. We don't know if that's true. How fun.

Dr. Moya McTeer (7:29)

But we do know he lived in Egypt through his life. We know he was in Alexandria. He worked and wrote in and around the library there.

Dr. Claire Aubin (7:40)

Presumably he almost certainly lived the majority of his life. It's where he died. He died in Alexandria. We do know that one. When I was looking up things about him, I came up with a list of job titles. Yes, astronomer, mathematician, astrologer, geologist, General theorist, writer of treatises, much like ourselves, booked and busy, basically.

Dr. Moya McTeer (8:08)

Look, the natural philosophers back then there was the word scientist did not exist and they were just doing whatever they wanted to. What they followed their, the whims of their curiosity far.

Dr. Claire Aubin (8:22)

That's so wild to me because if you and I were like, right, so I'm making a hard pivot to philosophy. I'm making a hard pivot to me in my case math or whatever, someone would be like, can you do that? Like, do you know how to do that actually? Or are you just doing it? And they could just do it.

Dr. Moya McTeer (8:40)

Good. They could just do it. Look, I cannot say anything bad about someone else who couldn't choose a single direction for their career. Okay? Like, I have no leg to stand on there if I, I am falling very well into the ancient tradition of studying all of the things.

Dr. Claire Aubin (8:59)

Yeah, that is true. To be fair, you are like a sort of jack of all trades in terms of like being like astronomy and also folklore.

Dr. Moya McTeer (9:06)

Question mark.

Dr. Claire Aubin (9:07)

Why not do it at the same time? Why not? They miss and right. You were the first person to, to, to do that at Harvard. Yes.

Dr. Moya McTeer (9:14)

Mm, Yes. I had to convince the professors to let me study both of these fields.

Dr. Claire Aubin (9:19)

Were they like, these don't go well together and you're like, okay, let me introduce to you my boy, Ptolemy.

Dr. Moya McTeer (9:28)

Yes. There's a pre approved list of double majors at Harvard and astro and folklore not on that list unless you can make a case for it.

Dr. Claire Aubin (9:36)

Well, clearly you did, so that's great. Speaking of. We weren't speaking of this, but speaking of things that Ptolemy was doing. He's famous for writing some of the most important ancient theoretical works on astronomy and mathematics. Yes, yes.

Dr. Moya McTeer (9:53)

Yeah, we, we can't talk about Ptolemy without talking about the Almagest. He, he published, you know, over a dozen different treatises and works over his career. But the most famous of them was this 13 volume collection that he called the Mathematical collection, but we call it the Almagest. And it described the motion of stars and planets in the sky. He was following in the path of Hipparchus, who created one of the first star catalogs ever before Ptolemy came along and he created his own catalog of more than a thousand stars in the night sky. Most importantly, the fixed stars that didn't seem to move relative to each other. Of those fixed stars, he separated them into groups called constellations or catastarismi, as the ancient Greeks called them. And we use all but one of those 48 constellations today in 1922 or 1923. The International Astronomical Union officially declared 88 different constellations in the night sky. These are official regions that are around the asterisms, the pretty shapes that we see by connecting the lines between the stars. And because Ptolemy lived in Egypt, he didn't see most of the Southern hemisphere, so he didn't see the rest of those 40 constellations that the IAU designated, but he saw those 48. And the only one that we don't still use was the Argo Navis constellation. And that's just because it was really big. So we have split it up into, like, five different constellations now.

Dr. Claire Aubin (11:31)

So the issue is not that we. That he missed one, it's that he made one too big.

Dr. Moya McTeer (11:36)

Correct. Yeah.

Dr. Claire Aubin (11:37)

It was so, honestly, incredibly cool.

Dr. Moya McTeer (11:40)

Yeah. Because we use constellations as an easy way of identifying regions in the night sky. So those regions can't be too big. Or else if you say, look in Argo Navis, there's just so much sky to look for.

Dr. Claire Aubin (11:54)

And it is interesting also, like, we're already establishing some limitations here which I think will contribute enormously to what your issue is with him when we, when we get to that, where, like, he's saying, okay, I can observe this half of the night sky or this hemisphere. This is what I'm able to see. These are the constellations that exist, but there's another half that's. That's not there, which sounds really, like, silly on the front on the face of it. But in actuality, like, it shows a limitation to the scientific process in this. Or to his experience of. Of trying to establish scientific norms and data that. That then later shows up in. In other ways too, where these limitations actually really shape what we can understand about him and what he is able to understand about the universe.

Dr. Moya McTeer (12:41)

Yes. Although the extra information that he would have gotten from seeing the southern sky probably only would have taught him that the Earth was spherical, which people already knew by the time Ptolemy came around. Because when you can go from the north to the south or vice versa, what you end up seeing is that the angle, the orientation of objects in the sky flips. And so that gives you real experience, like seeing the curvature of the sphere of the universe, which does teach people that Earth isn't flat, but they knew that for a long time.

Dr. Claire Aubin (13:19)

So it is also interesting to get to talk about that, too, as being part of this episode, just in general, that there are a lot of misconceptions around what people know and when they know it, just based on things like written narrative, which does not accurately reflect human knowledge all the time, so much as it reflects knowledge that has been written down. Those are not the same thing. And it's very easy to mistake one for the other.

Dr. Moya McTeer (13:45)

Yeah. In folklore, we learned that so much knowledge was passed down orally, it was told through stories and passed on through poems and folklore. And we tend to give more weight to things that were written down and things that were proven with a, like, Western scientific method. But there's, you know, a lot of knowledge that that leaves out.

Dr. Claire Aubin (14:04)

Yeah, absolutely. So also with the Alma guest for people who are interested in history, because obviously we're on a history show also known as the Mathematica Syntaxis. In it, he tracks the apparent paths and motions of planets and stars. We're starting to reach the limit of my understanding of these things, but it's also enormously important for several reasons. One, like you said, he draws from people like Hipparchus as well as Aristotle as well as Babylonian astronomy, in order to comprehensively discuss potential models for the heavy heavens. And it's also the only surviving comprehensive ancient astronomical document that we have in its full and complete format, including reliable translations. And we have surviving translated Arabic copies from as early as the 9th century or around 800 CE. It's a very, very important document. And it's pretty incredible that we have this ancient document and essentially it's full, like, translated text. Like, we have it this far, this much later.

Dr. Moya McTeer (15:02)

Like, he was the. I don't know, like the George R R Martin of his day. Like, the fact that he was writing in ancient Greek and he was translated into Latin and Arabic and spread across Europe and the Middle east and Africa, like, that's incredible. They didn't have the printing press. There were people handwriting the Almagest because that's how important it was.