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April 18, 2005

The myth about Columbus and the shape of the Earth

In his April 3, 2005 New York Times column called It's a Flat World, After All, Thomas Friedman begins:

In 1492 Christopher Columbus set sail for India, going west. He had the Nina, the Pinta and the Santa Maria. He never did find India, but he called the people he met "Indians" and came home and reported to his king and queen: "The world is round."

This is just a throwaway anecdote, to set the frame for another of Friedman's typical banal outpourings of conventional wisdom. (Sorry to offend the many Friedman fans that are out there but I have never understood his appeal. Not only does he not seem to have any original insights but he also comes across as patronizing and condescending, especially towards the people of other countries.)

But this posting is not meant to poke fun at Friedman, as enjoyable as that might be. That is done much better by Matt Taibbi of the NY Press as he reviews Friedman's latest book which bears the name The World is Flat. It is instead intended to address one of my pet peeves, the widespread belief that at the time of Columbus' famous journey, he and almost everyone else believed that the Earth was flat.

This is just not true. So can we all get together and stamp out this myth once and for all?

Thomas Kuhn in his book The Copernican Revolution discusses the early cosmologies and shows quite clearly that the idea of the flat Earth went out very early in recorded history. As early as the seventh century BCE Anaximander of Miletus (624-546 BCE) thought that the Earth was in the shape of a wheel. By the fourth century BCE, most Greek philosophers and astronomers believed in a two-sphere universe, in which the Earth was a tiny sphere, surrounded by a much larger concentric rotating sphere in which the stars were embedded.

The beliefs in the sphericity of the Earth, even back in those early days, were based on careful observations and solid reasoning. The fact that ships moving away had their hulls disappear before the mast, the fact that if you were on high ground, you could see more of the ship than when you were at sea level, the circular edge of the shadow of the Earth on the Moon during lunar eclipses, were all convincing arguments against a flat Earth and educated people of that time accepted them.

In fact, there are references to the measurement of the Earth's circumference that appear in Aristotle's (384-322 BCE) writings but the first complete record of this measurement comes from the Eratosthenes (276-194 BCE), the librarian of Alexandria in what is now Egypt, who arrived at a figure that was only off by about 5% from present day measurements, which is remarkable. He obtained this value from observing that the length of the shadow cast by a vertical stick depended on its latitude.

Aristarchus (310-230 BCE) and others in the third century B.C.E had sophisticated measurements of the sizes of the Moon, the Sun, the various distances between them, etc. and all these things were widely known among educated people.

The idea of using the round Earth to sail westward to India was also suggested by geographer Strabo, who was born around 63 BCE.

All this was about 1,500 years before Columbus.

The idea that Columbus and the Spanish nobility may not have been aware of this knowledge is also a myth. Columbus knew the Earth was round as did the other educated people of Spain. The reason that Columbus found it hard to gain support for his expedition was not because people thought he would fall off the edge of the flat Earth, but because Columbus had come up with a dubious calculation for the radius of the Earth that was quite a bit smaller than the accepted value, and it was suspected that he had fudged the calculation in order to make his trip appear more feasible and worth supporting. If the better values for the radius were adopted, then his ships would not have been able to carry enough provisions to reach India.

So Columbus' arrival in America did not save him from falling off the edge of the Earth, it just saved him and his crew from starvation and death. If America had not been there, his ships would never have been able to make the long trip over the Atlantic and Pacific oceans.

So while it is true that in 1492 there were probably some people who thought that the Earth was flat (as there are probably still people now too), this was not the view of educated people, and definitely not true of Columbus and the people of the Spanish Royal Court.

So why is this myth so resilient? Is it because it makes a dramatic story? Is it still taught in history courses in American schools? Whatever the reason, it is time to put it to rest.

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Comments

What an interesting post Mano! I'm trying to figure out whether I believed Columbus thought the earth was flat before I started reading. I vaguely remember hearing somewhere that he did not, but there was no accompanying thorough explanation. As far as history courses, I don't remember a 15th century "flat earth" being specifically taught, but it was definitely never refuted for me either. It seems like it would be such a simple misconception to fix.
Do you think this is all part of our society's general disrespect for people in the past? One of my current history professors always feels the need to remind us not to downplay the intelligence of the people we are studying. For example, medieval heretics who believed that the devil made the earth and God made the heavens were not simply fatalists. They were trying to account for the presence of evil in a world they were told was made by a perfect God. I guess it makes us feel better about ourselves to demean those in the past...

Posted by Katie S on April 18, 2005 09:54 AM

Katie,

I think your history professor is quite right. We look back with hindsight and treat the people of those times as little better than morons.

In a series of postings beginning tomorrow, I am going to be looking at beliefs about the Copernican revolution which is riddled with myths that again (surprise!) make us look a lot smarter than the people of those times.

Actually, the more I read history, the more impressed I am with the people of those times who achieved so much with so few tools at their disposal.

Posted by Mano Singham on April 18, 2005 10:13 AM

I was definitely taught from about fourth grade on that Columbus didn't in fact prove that the Earth was round, but the myth was definitely quite pervasive up to that point.

It's funny, I don't even remember what sources I got it from, but I certainly heard it.

A favorite story of mine is about the time in my seventh-grade social studies class when the question of the day was "Why did Aristotle believe the world was round?" The girl the teacher called on to answer the question responded, apparently in earnest, "Because he saw pictures from outer space?"

Posted by Mark on April 18, 2005 11:21 AM

Mark,

That is a funny story. But it does illustrate how little we emphasize the power of observation and inference in the way we teach. Instead students have a lot of "received" information that they have been told and believe.

I have visited a lot of middle school science classrooms and sometimes ask students whether it is possible that the moon is half bright and half dark, and that the reason we see different phases of the moon is that the moon is rotating about its axis, showing us different amounts of bright and dark regions.

Students all say that that is a wrong model. But when I ask how we know that, they almost always say that it is because astronauts have gone to and around the moon. When I say that this fact was known way before that, they are baffled.

Posted by Mano Singham on April 18, 2005 01:53 PM

Mano,

I find it ironic that I read this entry yesterday morning and then went to a tutoring session later in the day where a student was writing a paper on the article. It may not have been the greatest or most original, but it provided me with the basis for the best tutoring session of the semester!

I know that when I was in elementary school, I was given the whole "proved the world is round, not flat" line on Columbus Day, but I also recall later teachers saying that was false. I think it was middle school or so, though, before someone gave a reason, namely that of taller items being visible for longer when moving away.

It seems to me that the problem here may not only be propagating myths to the younger generation but oversimplifying the things we teach them. It takes a bit more effort to come up with a way to explain why people knew the earth is round to a five-year-old, but it's quite possible, and, better, in my opinion, than training them to accept whatever we tell them as truth when there's no rational explanation.

There's also an awful lot to what you say about fooling ourselves into thinking that we're much more intelligent than the cultures that came before us. It may be tough for the modern day child of Enlightenment to accept, but anyone who had looked at ancient history should realize that there were a lot of intelligent people around before us. Look at the remains of Pompeii! They had regular plumbing in 79 A.D. and some cultures had innovations like that a thousand or more years earlier. Some places in this country probably didn't get that luxery until the twentieth century.

Posted by Nicole on April 19, 2005 08:54 AM

Actually, there is nothing in principle wrong with just telling young children stuff, since they may not be at the developmental stage to understand sophisticated arguments. Even our own knowledge is a mix of received knowledge and things we have worked out for ourselves.

But what I don't understand is that given the choice between two kinds of received knowledge, why we tell them stuff that is incorrect, like the Columbus-flat earth story. It is just as easy to tell them the correct story. The reason must be that peole believe the wrong story.

Posted by Mano Singham on April 19, 2005 02:17 PM

Well, the real problem for Friedman is that his flat-earth analogy fails because he is alluding to the wrong sense of "flat." From what I know of his book, he means the Earth is flat becase it is not "mountainous" -- that is, in the wired, connected world of today no one or no culture will occupy the economically advantageous high-ground, in other words. So this has nothing to do with the Earth's being a big sphere or not. In fact a very smooth sphere is flat in this sense too. I believe many if not most Europeans knew of the existence of the Alps and that therefore the Earth was not "flat."

Posted by Daniel Zanger on April 22, 2005 01:04 PM

Columbus, from everything I've read, simply made a potentially disastrous miscalculation about the size of the Earth and refused to accept any evidence that he was wrong. As Mano says, educated people of the 15th century knew full well that the world was round, debates about the status of the antipodeans having fizzled out centuries earlier. Having read the NY Press beating the hell out of Friedman's prose style, I wasn't leaning towards reading Friedman's newest in any case, but I took a special thrill in his whole metaphor being basically nonsensical.

Posted by Steve Cook on April 24, 2005 04:54 PM

That is a really interesting link, Steve. It fills in some of the gaps in the Columbus story. Tracing the origins of the myth to Letronne and to its American popularization to Washington Irving was fascinating.

Posted by Mano Singham on April 25, 2005 09:10 AM

Thanks, Mano.

Are you making a pedagogical point with your recent posts, or is this blog actually focused on the history of science? (If it is and you're interested in readership outside the Case community, I'll sidebar it on snarkout.org, which is my personal site.)

Posted by Steve on April 25, 2005 10:18 AM

Well, this blog is many things, which is part of its problem. I write about whatever happens to interest me. Since my basic interest is in the history and philosophy of science, this is what most entries will be about. But as the masthead suggests, I will be wandering farther afield now and then.

Posted by Mano Singham on April 25, 2005 12:35 PM

The myth of Columbus and the flat earth lives on, and many of the efforts to expunge it have failed. I have sent repeated letters to the editors of the New York Times, but they saw nothing to be concerned about. The correspondence is posted on History News Network,
http://hnn.us/readcomment.php?id=58900#58900.

On the brighter side, the Economist in London did print two letters correcting the fable, as did the Washington Post Book World several years ago. The mythologizers are adamant and remorseless in their illusions and impervious to reason, but such is the power of myth.

Keep up the good work.

Posted by Vince Treacy on April 30, 2005 03:00 PM