Cosmos #3. Hypatia and the library

This is the last of three annotated transcripts of segments on ancient Greek science from Carl Sagan’s Cosmos (1980). See my introduction in part 1 on the impact Cosmos has had, its extraordinary influence in propagating some myths, and in creating others; and my introduction in part 2 on how some misinformation is a direct result of Sagan’s choice to set up science and religion as antithetical to one another.

This final episode is about Alexandria, and the idea that knowledge is something to be treasured. Sagan is right about that. But he’s wrong when it comes to his moral condemnation of the loss of knowledge. He wants to blame someone, and religion is in his sights. He’s right that the loss of knowledge isn’t a good thing -- but it’s also a historical inevitability.

Episode 13. ‘Who speaks for earth?’

YouTube link. First broadcast 21 December 1980.

Carl Sagan:
One of the great revelations of the age of space exploration is the image of the earth, finite and lonely, somehow vulnerable, bearing the entire human species through the oceans of space and time.

But this is an ancient perception. In the 3rd century BC our planet was mapped, and accurately measured, by a Greek scientist named Eratosthenes, who worked in Egypt. This was the world as he knew it. Eratosthenes was the director of the great library of Alexandria, the center of science and learning in the ancient world.

An ancient atlas: Ptolemy’s latitude and longitude data rendered onto Ptolemy’s own projection by Hans van Deukeren. Ptolemy’s atlas followed in the footsteps of several earlier ones, especially Marinus of Tyre, but Eratosthenes was the grandfather of ancient cartography. Eratosthenes’ atlas probably didn’t look much like this, though. Much or most of Ptolemy’s data came from Roman-era surveys; we don’t know what projection Eratosthenes used, but it wasn’t this one; and it’s possible Eratosthenes didn’t arrange his map with north at the top.

Aristotle had argued that humanity was divided into Greeks and everybody else, who he called ‘barbarians’; and that the Greeks should keep themselves racially pure. He taught it was fitting for the Greeks to enslave other peoples. But Eratosthenes criticized Aristotle for his blind chauvinism. He believed there was good and bad in every nation. The Greek conquerors had invented a new god for the Egyptians, but he looked remarkably Greek. Alexander was portrayed as pharaoh in a gesture to the Egyptians. But in practice, the Greeks were confident of their superiority. The casual protests of the librarian hardly constituted a serious challenge to prevailing prejudices. Their world was as imperfect as our own.

Sagan is basically right about Aristotle -- certainly in his criticism of Aristotle’s thinking on slavery, at least, which is awful enough that you will want to shower after reading it (Politics 1.2 = 1253b-1257a). However, ‘Eratosthenes criticized Aristotle’ is fantasy. We do not know what Eratosthenes thought about racism or even about Aristotle. The surviving fragments of Eratosthenes’ Geographica do not mention Aristotle.

But the Ptolemies, the Greek kings of Egypt who followed Alexander had at least this virtue: they supported the advancement of knowledge. Popular ideas about the nature of the cosmos were challenged, and some of them discarded. New ideas were proposed and found to be in better accord with the facts. There were imaginative proposals, vigorous debates, brilliant syntheses, and the resulting treasure of knowledge was recorded and preserved for centuries on these shelves. Science came of age in this library.

The Ptolemies didn’t merely collect old knowledge. They supported scientific research and generated new knowledge. The results were amazing. Eratosthenes accurately calculated the size of the Earth, he mapped it, and he argued that it could be circumnavigated. Hipparchus anticipated that stars come into being, slowly move during the course of centuries, and eventually perish. It was he who first cataloged the positions and magnitudes of the stars in order to determine whether there were such changes. Euclid produced a textbook on geometry which human beings learned from for 23 centuries. It’s still a great read, full of the most elegant proofs. Galen wrote basic works on healing and anatomy which dominated medicine until the Renaissance. These are just a few examples. There were dozens of great scholars here, and hundreds of fundamental discoveries.

Some of those discoveries have a distinctly modern ring. Apollonius of Perga studied the parabola and the ellipse, curves that we know today describe the paths of falling objects in a gravitational field, and space vehicles traveling between the planets. Heron of Alexandria invented steam engines and gear trains; he was the author of the first book on robots.

Imagine how different our world would be if those discoveries had been explained and used for the benefit of everyone, if the humane perspective of Eratosthenes had been widely adopted and applied. But this was not to be.

Let’s just repeat these two snippets, juxtaposed: Euclid produced a textbook on geometry which human beings learned from for 23 centuries. ... Galen wrote basic works on healing and anatomy which dominated medicine until the Renaissance. Imagine how different our world would be if those discoveries had been explained and used for the benefit of everyone ... But this was not to be. You don’t often see a normally level-headed person contradict themselves quite this quickly.

Alexandria was the greatest city the western world had ever seen. People from all nations came here to live, to trade, to learn. On a given day these harbors were thronged with merchants, and scholars, tourists. It’s probably here that the word ‘cosmopolitan’ realized its true meaning, of a citizen not just of a nation, but of the cosmos. To be a citizen of the cosmos. Here were clearly the seeds of our modern world.

But why didn’t they take root and flourish? Why, instead, did the west slumber through a thousand years of darkness until Columbus and Copernicus and their contemporaries rediscovered the work done here? I cannot give you a simple answer but I do know this: there is no record in the entire history of the library that any of the illustrious scholars and scientists who worked here ever seriously challenged a single political or economic or religious assumption of the society in which they lived. The permanence of the stars was questioned. The justice of slavery was not.

Columbus and Copernicus did not ‘rediscover’ anything. Columbus’ ambitions were solely colonial. He went out of his way to reject Eratosthenes’ work on the size of the earth when his opponents tried to remind him of it in Salamanca, in favour of guesswork and incomplete reports by Marinus of Tyre, Marco Polo, and Pierre D’Ailly. Copernicus should really be credited as a discoverer rather than a rediscoverer. His idol wasn’t any of the Alexandrian researchers, but Pythagoras, whom Sagan rightly casts as a mystic (see part 2). Neither of them knew or worked with any ancient sources that were obscure to their contemporaries.

Science and learning in general were the preserve of the privileged few. The vast population of this city had not the vaguest notion of the great discoveries being made within these walls. How could they? The new findings were not explained or popularized. The progress made here benefited them little. Science was not part of their lives.

The discoveries in mechanics, say or steam technology mainly were applied to the perfection of weapons, to the encouragement of superstition, to the amusement of kings. Scientists never seemed to grasp the enormous potential of machines to free people from arduous and repetitive labor. The intellectual achievements of antiquity had few practical applications. Science never captured the imagination of the multitude. There was no counterbalance to stagnation, to pessimism, to the most abject surrender to mysticism. So when at long last the mob came to burn the place down, there was nobody to stop them.

Sagan’s thesis that slavery obstructed the development of ‘science’ -- though really it sounds like he’s talking about industrial engineering, not science -- is coherent, but hugely over-simplified. The connection between slavery and something as distantly connected as engineering is always going to be a complex one, dependent on a huge range of historical circumstances. The main impact of slavery, insofar as it had anything to do with engineering, was economic. It’s a bit of a trite platitude these days that a slave economy had no need, and no room, for an industrial revolution. On that view, it’s true that it was impossible for industrial engineering to benefit society at large -- but not because of ‘mysticism’, or ‘pessimism’, or a failure of imagination; but because it was economically impossible. There’s probably some truth to that platitude. But the subject of what the Romans didn’t invent involves speculation and complexities. OK, maybe they didn’t have an economic framework that would reward that kind of industrialisation. But as well as that, they didn’t prize fuel (coal); they didn’t know Boyle’s Law; hell, they didn’t even know Newton’s Laws, not even the First Law. Steam engines depend on all of these things, including the more sophisticated Third Law, that every force has an opposing force. Like it or not, the theoretical considerations are important. Heron probably had only a hazy idea of how his steam engine worked. For the ancients it was a curiosity, not a tool: you can’t scale an industrial tool if you don’t understand how it works. We’ll hopefully all agree with Sagan that slavery is a bad thing, and that the monstrousness of slavery makes any society like that a model to avoid. But, as so often with Sagan’s historical arguments, there’s absolutely no reason to bring mysticism or superstition into it.

Let me tell you about the end. It’s a story about the last scientist to work in this place. A mathematician, astronomer, physicist, and head of the school of Neo-Platonic philosophy in Alexandria. That’s an extraordinary range of accomplishments for any individual, in any age. Her name was Hypatia. She was born in this city in the year 370 AD.

We do not know the date of Hypatia’s birth. ‘370’ is an estimate based on guessing her age at the time of her death in 415 (Sagan reports her death-date below accurately).

This was a time when women had essentially no options. They were considered property. Nevertheless, Hypatia was able to move freely, unself-consciously through traditional male domains. By all accounts she was a great beauty. And although she had many suitors, she had no interest in marriage.

The Alexandria of Hypatia’s time, by then long under Roman rule, was a city in grave conflict. Slavery, the cancer of the ancient world, had sapped classical civilization of its vitality. The growing Christian church was consolidating its power and attempting to eradicate pagan influence and culture. Hypatia stood at the focus, at the epicenter of mighty social forces. Cyril, the bishop of Alexandria, despised her: in part because of her close friendship with a Roman governor, but also because she symbolized, she was a symbol of learning and science which were largely identified by the early church with paganism.

In great personal danger Hypatia continued to teach and to publish, until in the year 415 AD, on her way to work, she was set upon by a fanatical mob of Cyril’s followers. They dragged her from her chariot, tore off her clothes, and flayed her flesh from her bones with abalone shells. Her remains were burned, her works obliterated, her name forgotten. Cyril was made a saint.

The glory you see around me is nothing but a memory. It does not exist. The last remains of the library were destroyed within a year of Hypatia’s death.

When Hypatia died, in 415, the Serapeum had been gone for 24 years. It was destroyed in 391. I won’t labour the story of exactly how she died, though there are some problems there too. Sagan also does not mention that one of Hypatia’s best teacher-student relationships was with Synesius, a Christian, who became bishop of Ptolemais and Metropolitan of Pentapolis in 410. As to the library itself: it’s hard to gauge how much of a library existed in the Serapeum in 391. There’s no mention of it in the accounts of the temple’s destruction (Theodoret, History of the church 5.22; Eunapius, Lives of the sophists 472). Ammianus, writing in the first part of the 300s, refers to a Serapeum library in the past tense, and gives the distinct impression that it was destroyed in Caesar’s invasion in 48 BCE (Ammianus Marcellinus 22.16.12-13). But there are some sensible counter-arguments too. Alexandria was certainly still a centre of learning. The fact that Theodoret’s and Eunapius’ terse accounts don’t mention books doesn’t mean they weren’t there: it was first and foremost a temple after all. Ammianus is definitely confused about the multiple libraries in classical Alexandria, and appears to have mixed up the Serapeum with the royal library (it was the latter that was destroyed in Caesar’s invasion). Aphthonius, writing in the late 300s (or even later?) describes public book collections in rooms off the temple colonnades, though we can’t be sure his rhetorical exercise is an eyewitness account (Progymnasmata 48 ed. von Spengel; §12 tr. M. Heath). Eunapius talks of Alexandria as ‘a sort of sacred world, because of the temple of Serapis’, but he says this in the context of describing the hordes of students that thronged to become disciples of one Antoninus, who supposedly foretold that the end of the Serapeum would coincide with the death of his philosophy (Lives of the sophists 471(a), 471(b)). That sure sounds like the Serapeum was still an intellectual centre -- or if not, then at least an important element of Alexandrian cultural life. It’s still pretty vague. There’s enough for some people to believe some fashion of library still existed in 391. But it won’t convince everyone, and there’s certainly no exactness about what did or didn’t exist. If, say, Eunapius’ Antoninus really was a mystic-philosopher, in a sort of Pythagoras-cum-Apollonius-of-Tyana vein, and if that’s representative of what kind of teaching went on at the Serapeum, then it’d be hard to think very highly of its culture. (Who knows, maybe the Serapeum was a bad spot in Alexandria’s intellectual landscape! Hypatia’s mathematical expertise survived it by a few decades, anyway.)

It’s as if an entire civilization had undergone a sort of self-inflicted radical brain surgery so that most of its memories, discoveries, ideas, and passions were irrevocably wiped out. The loss was incalculable. In some cases, we know only the tantalizing titles of books that had been destroyed. In most cases, we know neither the titles nor the authors.

It is vanishingly unlikely that anything at all was lost in 391 that wouldn’t have been lost anyway. The ancient Mediterranean had thousands of libraries. Any book that depended on a single library for its survival was already doomed, because no ancient library has survived to the present. To imagine the survival of any ancient library from antiquity to the present day is to imagine a miracle. We have reports of many ancient library fires. The case of Alexandria is famous because the library was big during the Ptolemaic era -- and because Sagan has publicised it -- not because its collection was unlike anything else. When 1st century CE Egyptian scribes made the sole surviving copy of Aristotle’s Constitution of the Athenians (BL pap. 131), they certainly didn’t do it in Alexandria: you don’t make a 200 km hike for a job done on the cheap (the papyrus is recycled). Alexandria has a place of honour in any account of the development of human knowledge. But the story of the loss of ancient knowledge is a story of economics, not of library burnings. In that story, Alexandria doesn’t even warrant a footnote.

We do know that in this library there were 123 different plays by Sophocles, of which only seven have survived to our time. One of those seven is Oedipus rex [Oedipus the king]. Similar numbers apply to the lost works of Aeschylus, Euripides, Aristophanes. It’s a little as if the only surviving works of a man named William Shakespeare were Coriolanus and A winter’s tale, although we had heard that he had written some other things which were highly prized in his time -- plays called Hamlet, Macbeth, A midsummer night’s dream, Julius Caesar, King Lear, Romeo and Juliet.

History is full of people who out of fear, or ignorance, or the lust for power have destroyed treasures of immeasurable value, which truly belong to all of us. We must not let it happen again.

This last bit lays bare the fundamental flaw in Sagan’s thinking. He sees the loss of knowledge as a crime. Where there’s a crime, there must be a criminal. But that isn’t how it works. The default state of knowledge is not to be preserved. Don’t believe me? Go and try to read a file off a 5½" floppy disk. Hell, try to read a file off a CD-ROM that you burned ten years ago. Preserving knowledge doesn’t mean storage, it means copying, endlessly and without pause. If the reproduction technology is laborious or expensive, as it was in antiquity, it’ll be that much harder. It doesn’t take much for the process to fail. Even in antiquity, you can find people in the 2nd century CE bemoaning the fact that they can no longer find a copy of one of Cicero’s speeches. As much as half the Epic Cycle may have been lost by the time of Augustus. We don’t know of any ancient writer who ever got to see a copy of book 2 of Aristotle’s Poetics (other than Aristotle himself). Now, that’s trying to preserve knowledge for just a handful of centuries. If you want it preserved for 1600 years, you have to imagine thousands of people collaborating, with no lasting supervision, no political continuity, no continuity in funding, and no mutual agreement. The fact that anything has survived that long is amazing. Even nowadays, a couple of decades of neglect would be enough to ensure the destruction of any modern library, acid-free paper or no acid-free paper. Ever heard how the video tapes of the Apollo 11 moon landing were lost? Or conversely, have you heard of the Archimedes palimpsest, and how new technological developments have allowed people to read heavily damaged texts that survived nowhere else? But were you aware that most of the damage to that book was done in the 1900s, not in the mediaeval period? That’s just how it is. Stuff gets lost, stuff gets damaged. If you wait long enough, every library disappears. Alexandria isn’t a tragedy. It’s a miracle that it happened at all, let alone that it lasted 7 centuries.