New Atheists love astronomer and science educator Neil deGrasse Tyson.  It’s not hard to see why, given that Tyson is a pretty lovable guy: he’s charismatic, articulate, poised, funny and does a good job of bringing science to the masses.  And this is something he did back in January where a rapper called “B.o.B.” began tweeting that the world is actually flat. Yes, this genius actually believes that the whole spherical world idea, known since the sixth century BC and proven by small things like Magellan’s circumnavigation and thousands of space flights, is actually a big conspiracy.  B.o.B also believes that genetically modified crops, the Holocaust, NASA and science generally are all conspiracies as well.  Because he’s a moron.

So Tyson did what a good science educator should do and gave B.o.B. and his fans a quick lesson in how we know that the earth is, in fact, not flat.  And he was doing well … until he tweeted this:

So according to Neil deGrasse Tyson, people 500 years ago believed the earth was flat.  Except, ummm, they didn’t.  Luckily there are a few people out there whose grasp of history is rather better than Tyson’s, so a few days later someone questioned the great man’s assertion:

But the great STEM Lord was having none of this and proceeded to use his mighty powers of sciency scienceness to make declarations about history because, science:

Ah – the “Dark Ages”!  So the impertinent peon was silenced and everyone got back to being all scientific and rational. Neil deGrasse Tyson had spoken and, being a scientist, what he had said must be right.  Because, science.

Except, he was wrong.

Inventing the Flat Earth

Tyson can perhaps be forgiven to a certain extent.  The idea that the knowledge of the shape of the earth was “lost to the Dark Ages” and only finally restored by Columbus’ voyage is still commonly believed and is very much a part of the American foundation myth.  No doubt like most of his generation Tyson would have have seen the 1951 Bugs Bunny cartoon “Hare We Go” in which Bugs helps Columbus prove the earth is round in the face of a medieval king’s scepticism.  And as recently as 1983, when Tyson was in college, Daniel Boorstin was able to write:

“A Europe-wide phenomenon of scholarly amnesia …. afflicted the continent from A.D. 300 to at least 1300.  During those centuries Christian faith and dogma suppressed the useful image of the world that had been so slowly, so painfully and so scrupulously drawn by ancient geographers.” (The Discoverers, 1983, p. 100)

Boorstin goes on to pour scorn on the “legion of Christian geographers” who followed the path of the stupid sixth century flat-earther Cosmas Indicopleustes and so plunged Europe into this millennium of ignorance.  So, for some at least, the idea of the medieval belief in a flat earth remains a useful stick with which to beat those detested “Dark Ages” and Christianity’s dead hand on “progress”.

Back in 2012 New Atheist blogger Donald Prothero took hold of the flat earth stick and gave Christianity a vigorous beating.  Prothero is Professor of Geology at Occidental College in Los Angeles and he had just seen Alejandro Amenábar’s woeful tripe Agora, so naturally he felt these things qualified him to lecture the readers of Skepticblog about history.  In a post entitled “Hypatia, Agora and Religion vs. Science”, he praised Amenábar’s highly distorted biopic of Hypatia and used that as a jumping off point for a sermon about the alleged suppression of science by religion that was peppered with classic New Atheist bad history howlers.  As I’ve detailed elsewhere, the result was total butchery of the facts, but he finished in grand style, with a reference to “Christians suppressing the heretical notion that the Earth is round”, showing that the Medieval Flat Earth Myth is alive and kicking at the more clueless end of the New Atheist paddling pool.

And it’s easy to see why this myth is so hard for the New Atheists to resist – it conforms to every element of their pseudo historical metamyth.  We have the wise and rational Greeks discovering the earth is a sphere using science.  Then the terrible Christians destroying this knowledge (presumably by burning down the Great Library of Alexandria and murdering Hypatia), plunging Europe into a 1000 year Dark Age of Church oppression where the Bible must be interpreted literally at all times.  And finally, a brave rationalist arising at the dawn of Modernity to boldly defy the Church proves the Greeks right by sailing to the Americas.

But those of us who actually care to check facts – something the New Atheists preach about but, strangely, rarely do on matters historical – know that this is all complete crap.  Anyone who can bother to read Jeffrey Burton Russell’s Inventing the Flat Earth: Columbus and Modern Historians (1991), Google a Wikipedia article or even read Cracked.com can get a solid understanding of how the idea that the Medieval Church suppressed the concept of a spherical earth and taught that the earth was flat is a wholesale fiction that arose in the nineteenth century.  They can read up on how, in 1828, the American novelist Washington Irving invented the whole idea of a conflict between the Church and Columbus to spice up the otherwise rather dull story in his fictionalised biography A History of the Life and Voyages of Christopher Columbus.  This book, unfortunately, became the best selling biography of Columbus for the next century, and so fixed the myth in the English speaking world as something “everyone knows”.  Despite the fact it was completely made up.

The Medieval Sphere of the World

In fact, the idea that the earth was a sphere was never disputed in the Middle Ages.  The weird flat earth cosmology of the sixth century Byzantine writer Cosmas Indicopleustes, who Boorstin erroneously blamed for his alleged centuries of “scholarly amnesia”, was in fact virtually unknown even in the Eastern Roman Empire and was completely unknown in western medieval Europe.  His obscure book did not appear in a Latin edition in Europe until 1706.

The writer who actually influenced western medieval thinking on the matter was Plato, because his Timaeus – the only Platonic dialogue known in the early medieval west and one of the most influential works throughout the period – stated categorically that the Creator “made the world in the form of a globe, round as from a lathe, having its extremes in every direction equidistant from the centre, the most perfect and the most like itself of all figures”.  And if an authority as august as Plato said so, that, as far as most medieval scholars were concerned, was that.

Though after the influx of lost Greek learning via translations from the Arabic in the twelfth century, they were also well aware of the rational proofs of the shape of the earth established by the ancient astronomers and physicists.  In his introduction to astronomy, the Tractatus de Sphaera (“Treatise on the Sphere” – the title is something of a hint), John Sacrobosco (c.1195- c.1256) gave several proofs of the shape of the earth:

“That the earth, too, is round is shown thus. The signs and stars do not rise and set the same for all men everywhere but rise and set sooner for those in the east than for those in the west; and of this there is no other cause than the bulge of the earth. Moreover, celestial phenomena evidence that they rise sooner for Orientals than for westerners. For one and the same eclipse of the moon which appears to us in the first hour of the night appears to Orientals about the third hour of the night, which proves that they had night and sunset before we did, of which setting the bulge of the earth is the cause.” (Sacrobosco, Tractatus, Ch. I.9)

He also shows how it can be known that the surface of the sea is, therefore, also spherical:

“That the water has a bulge and is approximately round is shown thus: Let a signal be set up on the seacoast and a ship leave port and sail away so far that the eye of a person standing at the foot of the mast can no longer discern the signal. Yet if the ship is stopped, the eye of the same person, if he has climbed to the top of the mast, will see the signal clearly. Yet the eye of a person at the bottom of the mast ought to see the signal better than he who is at the top, as is shown by drawing straight lines from both to the signal. And there is no other explanation of this thing than the bulge of the water.” (Sacrobosco, Tractatus, Ch. I.11)

Sacrobosco’s book was the standard text in medieval universities for anyone who studied astronomy, which was essentially anyone who took an Arts Degree.  So the idea that the earth was round was so well known and unquestioned that Thomas Aquinas used it as an illustrative example of an accepted, objective and scientific fact:

“Both an astronomer and a physical scientist may demonstrate the same conclusion, for instance that the earth is spherical; the first, however, works in a mathematical medium prescinding from material qualities, while for the second his medium is the observation of material bodies through the senses.” (Summa Theologica, q.1, a.1).

In short, this was all standard, accepted and unquestioned as far as medieval scholars were concerned.  As Stephen Jay Gould (a scientist who actually did bother to check his facts on history) summarised it:

” … there never was a period of ‘flat Earth darkness’ among scholars (regardless of how the public at large may have conceptualized our planet both then and now). Greek knowledge of sphericity never faded, and all major medieval scholars accepted the Earth’s roundness as an established fact of cosmology.” (Gould, “The late birth of a flat earth”, Dinosaur in a Haystack: Reflections in Natural History, pp. 38–50)

“But, what about … ?”

So that, you would think, settles that.  But myths die hard and even those who are made aware of all the abundant evidence that this one is total bunk find ways to clutch at some straws.  One such is to try to claim that while some or even most medieval scholars accepted that the earth was round, there were still a few who did not.  And so it’s claimed that there was some kind of “dispute” over the issue.  Some of those who try to argue along these lines point to assertions made in the Middle Ages about “the antipodes”, disputing that they exist.  For example:

“As to the fable that there are Antipodes, that is to say, men on the opposite side of the earth, where the sun rises when it sets on us, men who walk with their feet opposite ours, there is no reason for believing it.” (Augustine, De Civitate Dei, XVI.9)

In 748 AD Pope Zachary declared the belief “that beneath the earth there was another world and other men, another sun and moon” to be heretical and rejection of this antipodean world is found elsewhere in early medieval writings.

But these are not references to any dispute about the shape of the earth.  These writers are echoing a dispute between ancient philosophers about whether the other side of the round earth could have its own lands and inhabitants.  This was disputed on the grounds that the equatorial region was considered so hot that it was impassible, though for Christian writers it was also considered impossible because they believed mankind had been created in the northern hemisphere (with Eden being in the region of Jerusalem) and then spread out from Mount Ararat after the Great Flood.  So Noah’s descendants could not have passed the equator to populate the southern hemisphere and any lands which may be there would be uninhabited.

As it happens, it was medieval travellers who ventured as far afield as Sri Lanka, Java and Sumatra by the thirteenth century that finally debunked the idea of an impassable equatorial zone and put the debate about the antipodes to rest.  But the point here is that this dispute was not about the shape of the earth – on the contrary, it presupposed the earth was spherical.

“Okay, but what about … ?”

A few more tenacious defenders of the myth try even harder and come up with a passage from Isidore of Seville that they think is a clincher.  Isidore’s Etymologiae was an encyclopaedia (of sorts) compiled by the sixth century bishop of Seville (c. 560-636) and organised according to his often highly fanciful etymologies for key words.  Given that the early medieval period had very few such works of general reference, it was a widely copied and read text.  Therefore if Isidore said the earth was anything other than round, surely this indicates that there was some dispute or doubt on the matter, at least in the early part of the medieval era.  And some feel this passage indicates just that:

“It is in virtue of its circular form that we speak of the orbis terrae (orb of the earth), because it is like a wheel; hence the name for a small wheel is orbiculus.  The ocean flowing around the land encircles its limits on all sides. It is divided into three parts, the first is called Asia, the second Europe and the third Africa.” (Isidore, “De orbe” in Etymologiae,  XIV.2)

If here we have one of the most influential scholars of the early Middle Ages saying the earth is shaped “like a wheel” then surely this is clear evidence of at least some belief that it was something other than round, right?  Well, actually, wrong.  Sorry.

Elsewhere in the Etymologiae Isidore makes it clear that he understood the earth to be spherical.  For example, here is how he defines and describes the heavens:

“The sphere (sphaera) of the sky is so named because it has a round shape in appearance. But anything of such a shape is called a sphaera by the Greeks from its roundness, such as the balls that children play with. Now philosophers say that the sky is completely convex, in the shape of a sphere, equal on every side, enclosing the earth” (Isidore, “De partibus caeli” in Etymologiae, XIII.5)

Obviously if the spherical heavens are enclosing the earth and are “equal on every side”, the earth too must be spherical.  And in another of his works, De natura rerum, he makes the same point:

“The earth, as Hyginus states, is situated in the middle of the universe. Equidistant from all of [the universe’s parts] it occupies the centre.  The ocean, spread out by the limit of the circumference of the sphere, bathes virtually the entire globe.” (Isidore, De natura rerum,  XLVIII)

The explicit references here to “the sphere” and “the globe” here are quite clear.  Finally he makes the point again in Book XIV, just before the “like a wheel” passage quoted above:

“The earth is placed in the central region of the [universe], standing fast in the centre equidistant from all other parts of the sky.”  (Isidore, “De terra” in Etymologiae,  XIV.1)

So what was he saying when he goes on to write in the next section of Book XIV that the “orbis terrae” is “like a wheel”?  The key to understanding this apparent contradiction lies in the quote from De natura rerum above.  He notes that the ocean “bathes virtually the entire globe”.  This follows the Greeks, who thought that most of the earth was covered in ocean and that the three continents took up only a portion in the northern hemisphere, with the existence of any land masses in the southern hemisphere merely a conjecture, as discussed above.  More specifically, following Aristotle, they held that the continents occupied the northern temperate zone, between the frigid arctic zone and the torrid and impassable equatorial one:

  

So how can the “orbis terrae” be “like wheel” while the “globus” is a sphere?  Because when Isidore is referring to the “orbis terrae” he’s referring to the inhabited northern temperate zone in which the three continents sit and he’s imagining this zone as a three dimensional slice with the land masses on the outer rim of the “wheel”.  There is no contradiction here once we understand the cosmology Isidore inherited from Aristotle (via Macrobius).

“Fine, but then there’s …”

Which leaves just one last medieval scholar that some try to claim as a flat-earther, this time from the other end of the medieval era.  Alonso Tostado (c. 1400-1455) was a Franciscan theologian and commentator on the Bible and, for most modern readers, about as obscure a scholar as you could possibly get.  There is no English translation of any of his works largely because anyone who is likely to want to read them would almost certainly be fluent in Latin. So how does he get dragooned into the rear-guard action in defence of some ragged remnant of the Flat Earth Myth?  Well, this is because he is mentioned tangentially in Jeffrey Burton Russell’s Inventing the Flat Earth: Columbus and Modern Historians, tucked away in an end note.  In a note on Edward Grant’s conclusion that “there were no educated people who denied the roundness of the earth in the fifteenth century” (Russell, p. 14), Russell deals with a couple who could be said to have done so.  He dismisses one, but provisionally accepts that Tostado may be “an anomaly” in this regard and refers to Tostado’s Commentaria in Genesim, though without giving a more specific citation.

He seems to be referring to Tostado’s commentary on Genesis 1:9 – “And God said, ‘Let the water under the sky be gathered to one place, and let dry ground appear” – where Tostado is disputing the opinions of “some ignorant men” and their view that “the entire world was spherical”.  But read in context the issue is not the shape of the world now, but a question of what we could call “flood geology”: was the earth’s surface wholly smooth before the Great Flood and the “hollows and mountains” seen today created by the Deluge or did they exist before this and were in fact created in the “gathering of the waters” on the second day of creation?  Against the “ignorant men”, Tostado argues for the latter on this burning issue (all this is at the end of “Quaestio XIX” and the beginning of “Quaestio XX” of his Commentaria in Genesim for anyone who wants to drag themselves through the turgid Latin). And to show that Tostado was not actually any kind of “anomaly” and somehow, alone of any scholar in his age, believed that the earth was not round, here is a passage from another of his works that shows he definitely understood the earth was a sphere:

“If we put a man in any part of the world, and we draw the diameter of the earth passing from his feet to the other extremity of the earth, and through the centre of the earth, and if there is another man in that extremity which is touched by the other part of the diameter, those men, who are the diameter of the earth distant from themselves, are called the antipodes of each other.” (Tostado, Commentaria in Deuteronomium, Qaestio IV Cap. VII)

So Tostado clearly understood the earth to be spherical.  No anomalies here.

The Peasants are Revolting!

By now it should be quite clear that the Flat Earth Myth has no foundation and that the knowledge of the sphericity of the earth was not, despite Neil deGrasse Tyson’s confident tweet, “lost to the Dark Ages”.  As we’ve seen, there were no medieval scholars in western Europe in the entire 1000 years before Columbus who considered the earth to be anything other than a sphere. But deGrasse Tyson’s Twitter followers were not going stand for those who continued to point out that the great man was wrong.  One “Mark Bauermeister” showed he had zero knowledge of medieval exegesis by declaring “Biblical literalism was widespread in the dark ages (obviously)”.  When challenged on this claim he went even more off the deep end: “Remember the black death? Rats were allowed to roam free because people considered cats the spawn of Satan.”  This is a reference to yet another myth, that there was some kind of medieval massacre of cats (there wasn’t) which caused rats to spread the plagues of the 1340s (See my article “Cats, the Black Death and Pope” for a detailed debunking of this one).  Why these pandemics also hit non-Christian regions such as vast tracts of central Asia and the Middle East every bit as hard as Europe is not explained by Mr Bauermeister. Back to the original claim – further insistence that the Flat Earth Myth was, indeed, a myth was met by more children’s picture book level historical analysis.  

A certain “Jake Peninger” solemnly assured us that “it wasnt (sic) widely known and the knowledge didnt (sic) spread. It has only been common knowlege (sic) for 5 centuries”, going on to claim “education in the middle ages was scarce. Like i said, it was not common knowledge.” And this is the last bastion in the defence of the Flat Earth Myth.  When forced to accept that the Church did not teach that the Bible was literally true on this point and that no scholar in the Middle Ages believed that the earth was anything other than spherical, it is then claimed that perhaps the scholars knew this, but it was not “common knowledge” and the revolting peasants still thought the earth was flat. Of course, the nature of our source material is such that it is hard to know what the peasants or even the unlearned non-nobles generally believed about pretty much anything.  But the evidence we do have indicates that, in fact, it was common knowledge and was widely understood and accepted by the unlearned as well. For example, the popular fourteenth century collection of travellers’ tales, The Travels of Sir John Mandeville, includes a story of a man who unwittingly returns to his homeland from the west by sailing into the east:

“I have often thought of a story I have heard, when I was young, of a worthy man of our country who went once upon a time to see the world. He passed India and many isles beyond India, where there are more than five thousand isles, and travelled so far by land and sea, girdling the globe, that he found an isle where he heard his own language being spoken…He marvelled greatly, for he did not understand how this could be. But I conjecture that he had travelled so far over land and sea, circumnavigating the earth, that he had come to his own borders; if he had gone a bit further, he would have come to his own district.”

(Travels, XX)

This is in a work of often fanciful tales written for non-scholars and intended to be read aloud for entertainment. Similarly we have multiple passing references to the shape of the earth in a variety of vernacular works intended for an unlearned audience which use the same similes – rond comme une pomme (“round like an apple”) or rund cume pelote (“round like a ball”). Romances, which were written in part to be read to illiterate audiences, include references to the earth sitting like a yolk within the egg of the heavens. Both the Old French Roman d’Eneas and Le Couronement de Louis have references to people circumnavigating the earth. The Roman de Thebes includes a description of a map in the tent of a king divided into the five zones of Greek geography (see above) – a division that only makes sense with a spherical world. In the Alexandre de Paris Darius is depicted sending Alexander a present of a ball implying he’s a child, whereas Alexander declares it a sign that he would conquer the world, implying the audience understood that the earth was ball-shaped. The same poem ends with Alexander’s tomb being topped by a statue of him holding up an apple, symbolising his dominance of the whole world.  

    This image would have been familiar to medieval audiences, since royal regalia often included the orb, representing the king’s earthly authority. In an age where iconography was a shared language for the illiterate masses, the image of the king on his throne, holding the sceptre and the orb (or rather the globus cruciger, an orb topped with the cross), would have been a familiar one.  And the orb is clearly not a disc.   Finally, the Old Norse King’s Mirror depicts a father explaining to his son the way the sun’s light strikes the earth using a thought experiment that assumes he already knows the earth is a sphere:

“If you take an apple and hang it close to the flame, so near that it is heated, the apple will darken nearly half the room or even more. However, if you hang the apple near the wall, it will not get hot; the candle will light up the whole house; and the shadow on the wall where the apple hangs will be scarcely half as large as the apple itself. From this you may infer that the earth-circle is round like a ball and not equally near the sun at every point.”

  So much for the “dark ages”. Of course, this is not to say that there were not some or perhaps even many among the unlearned in the period who had no conception of the earth as a sphere.  Given that in 2012 a survey found that 26% of American respondents were under the impression the sun went around the earth and we get people like our idiot rapper friend B.o.B. trying to convince people the earth is flat even today, it’s very likely there were people similarly confused back then.  And some of the language used in popular medieval literature is sufficiently ambiguous that it may be that the writers though that the world was round like a wheel rather than round like an apple.  But there is sufficient evidence that knowledge the earth was a sphere was widespread or even common, even if we can’t know how common it was.  

Why It Matters  

Of course, the fact that the average person still gets their idea of medieval cosmology from a 1951 Bugs Bunny cartoon is not really the issue here.  The problem is that the Flat Earth Myth keeps popping up in New Atheist critiques of religion, despite it being patent nonsense.  If it were just people like Tyson’s Twitter defenders whose grasp of history was so inadequate that they believe this stupid myth this would not be an issue.  But when a man like Tyson, who is regarded as some kind of authority on all things (not just science), and who has 5.21 MILLION Twitter followers, peddles this pseudo historical crap it’s small wonder New Atheists have a warped view of history.  Donald Prothero is nowhere near as influential, but as an educator, it’s deeply concerning that he takes it upon himself to lecture others on this subject, despite the fact he doesn’t have the faintest idea what he’s talking about.   What we see here, in short, is everything that is wrong with New Atheist Bad History – outdated myths backed by garbled evidence peddled by non-historians who have irrelevant authority by merit of being scientists and who are motivated by an emotionally-driven ideological bias against religion.  The result is, yet again, total garbage presented uncritically by people who are meant to be rationalists and sceptics.  And that’s the problem.  

Edit (July 1 2016):    

Since I posted my article above, a list of errors of fact made by Neil deGrasse Tyson was posted on Hop’s Blog, entitled “Fact checking Neil deGrasse Tyson” and including his blunders over the Medieval flat earth myth.  Tyson commented on the post and included a defence of his comments about flat earth being “five centuries regressed in … thinking”.  Here’s what he said:  

“I neglected to mention that the “five-centuries” reference in my tweet the B.o.B refers to the dawn of the earliest maps of a spherical Earth. A time where all doubt was removed from the minds of cartographers. I am most fascinated by this transition of world view, before which everybody drew themselves in the center of a flat circle.”

  Unfortunately for Tyson, in trying to pretend he didn’t make a blunder he blundered further.  The transition from symbolic medieval mappae mundi to actual cartographic maps did not represent any “transition of world view” and it definitely didn’t indicate any final removal of “all doubt” about a flat earth.  As I detail in my blog post, there was no “doubt” to be finally “removed”.  And the earlier maps were iconographic clusters of symbolism overlaid over a very general and schematic cartographic rendition.  So to compare them to later actual cartographic charts is comparing apples to oranges and to conclude the difference between the two represents some change in “world view” or the removal of any “final doubts” is just pseudo historical garbage.   His attempted defence doesn’t seem to have cut much ice with the commenters at that blog and one of them was good enough to post a link to my article above to show exactly how wrong Tyson’s “history” actually was.

Edit (April 28 2021):

It appears Donald Prothero is persisting with his claims about a medieval flat earth belief. Prothero has now left Occidental College and apparently is a research associate in vertebrate palaeontology at the Natural History Museum of Los Angeles County. He is also a current fellow of the Committee for Skeptical Inquiry. Yet, despite having been told that his claims about the Church teaching the earth was flat are wrong, in his recent book The Story of Evolution in 25 Discoveries (Columbia University Press, 2020) Prothero repeats the myth on his book’s very first page. He claims:

Before 1543, almost all humans thought that the earth was flat and at the center of the universe and that the stars were tiny points of light on the dome of the heavens.

While, strictly speaking it is true that “almost all” people on earth in this period probably believed this (Chinese, Sub-Saharan, Asian, Oceanic and American cosmologies had a flat earth, with only the European and Muslim inheriting the Greek conception of the world), his reference to 1543 shows Prothero is totally confused. That is the date of the publication of Copernicus’ De revolutionibus orbium coelestium, which had absolutely nothing to do with the shape of the earth, which had been established as round for about a millennium by that stage, and was about a heliocentric model.

Prothero displays his confusion and ignorance of history further when he goes on to declare that Galileo’s telescopic observations discovered the stars “were not scattered on a big dome over our heads” and proclaims to his readers that “he confirmed Copernicus’ idea that the earth was just another planet orbiting the sun”. No-one thought the sky was a dome in Galileo’s time and Galileo did not “confirm” anything of the sort. Galileo made some arguments in favour of the Copernican model, but none of them were definitive and at least one of them was wildly wrong.

Prothero is yet another example of a scientist who is working from a cartoonish grasp of history that is mostly nonsense, but which he broadcasts to another generation of readers with great self-assurance nonetheless. Historians are constantly having to clean up after ignorant “skeptics” like Prothero.