
Columbus and the shape of the Earth, a “Holywood” story - diodorus
http://mappingignorance.org/2017/01/16/columbus-shape-earth-holywood-story/
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aetherson
For anyone reading the comments before the article: this article is not
principally about the banal fact that everyone knew that the Earth was round
in Columbus' time, nor that Columbus underestimated the size of the Earth.

It's about why the elites of Europe thought that a landmass like the Americas
was impossible. Which was new to me and quite interesting.

~~~
acqq
The main reason is not mentioned in the article but surely mentioned in the
book: the models always tried to assume that whats written in the Bible is
valid! As the Bible is "from God" and has "eternal truths" and it says nothing
about the new continent, therefore it can't exist.

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a3n
>It is well known that the great discoverer grossly underestimated the size of
the earth: whereas most of the astronomers of his time accepted a figure very
close to the real one, and based on Eratostenes measures in the 3rd century
BC, Columbus thought it was much smaller, so that the distance from Spain to
Japan crossing the Atlantic should be of around 3000 miles, instead of the
approximately 12000 miles really separating them.

Standard underestimation to get a government contract, after which it's too
expensive to switch contractors after the underestimation is discovered.

~~~
nerfhammer
He should have believed he was right because if he were wrong he would have
believed he was sending himself on a suicide mission. It was only blind luck
on his part that there happened to be another continent in the way.

~~~
goodcanadian
There is a theory that Columbus had information that there was indeed land at
the distance of America which he possibly assumed to be Asia which led to his
underestimate. Portuguese fishermen are the usually suggested source of this
information. I don't know whether there is much evidence to support this
theory, but there it is.

~~~
jcranmer
I would rule that theory unlikely.

The underlying idea of the theory is that fishermen discovered the Grand Banks
off of Newfoundland and incidentally discovered Newfoundland itself. When the
Grand Banks was discovered is unclear--it was definitely known in the early
1500s, but that postdates John Cabot's discovery of Newfoundland in 1497. The
usual claims of preemption seem to describe the date as "1400s".

The biggest hole in the theory as described is that the nonpublication of the
discovery is attributed to "fishermen keeping their new grounds secret," so
why would they confide their secrets in a (rival) navigator? It also makes
somewhat less sense that his voyages would have traveled in a southwesterly
direction rather than a northwesterly direction if he knew that the land were
to be found more to the north.

There is no real evidence to substantiate that fishermen found the Grand Banks
in the 1400s. The earliest claims seem to date to at best the 1580s or so and
have a vein of "we totally knew about that place but somehow lost track of it
until John Cabot found it again!" Given that the modern claims seem vague as
to whose fisherman it was that actually found them (Bristol, Basque, and
Portuguese have all been named), it seems more like an attempt to
retroactively claim primacy. There's been no archaeological evidence on
Newfoundland dating to the 15th century of any presence of cod fishermen--and
given the knowledge that by the end of the 16th century the industry did
produce a massive infrastructure on the coast, it seems unlikely that the lack
of evidence is because we haven't looked hard enough.

~~~
goodcanadian
While I am aware of what I'll call the "Grand Banks" theory, the one that I
read years ago referred specifically to the Caribbean. As to how Columbus got
the information, well, people talk when they are drunk, when they are
incentivised with money, just because they want to brag, and so on. Do I think
the theory is likely? Not really, but it does explain a few peculiarities
about what Columbus claimed and did.

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tpetricek
The article made me think of a recent book "The Invention of Science" almost
immediately - turns out the book is mentioned as one of the references - which
is well worth reading if you found the article interesting. It discussed the
story of the Earth in a lot more detail.

It is fascinating to read how amazing conclusions people inferred by following
perfectly sensible reasoning from basic assumptions they believed. It makes
you think about the perfectly sensible reasoning we are using today and what
our current ideas will seem completely silly in a few hundreds years!

~~~
acqq
> It makes you think about the perfectly sensible reasoning we are using today
> and what our current ideas will seem completely silly in a few hundreds
> years!

No, not in a way it was in the old times, at least not for the natural
sciences, and the book you mention very specifically argues why: the
"completely wrong" beliefs were possible before the "real" science, the later
always just limited by our measurements. Therefore, Newton formulas aren't
"completely wrong" even after Einstein, only not precise enough for the
measurements that were achieved shortly before Einstein.

The book in fact spends more chapters explaining exactly the difference
between the really modern science and the status before.

~~~
wtbob
But Ptolemy's formula's aren't completely wrong, either: they're actually very
effective at predicting the movements of the planets and stars — just not good
_enough_ , it turns out, and rather more complex than they need to be.

~~~
riffraff
This is an interesting thought. Not everything pre-scientific method is
completely wrong, but many things look like they were, e.g. :

* the idea that everything is made of (one of, or all) 4 elements

* humorist theory of disease

* belief in perpetual motion machines

* spontaneous generation

AFAICT all of these can be construed to be considered "good enough theories"
but they generally fail to make accurate predictions, which "good science"
doesn't.

~~~
acqq
I'd argue that even before the "good science" really established itself
broadly (that is, before the last few hundred years in Europe) there were the
results that have all the rights to be called "good science" and Ptolemy's
formulas actually have all the right to be recognized as "good science." Note,
the formulas, not the models that people believed, the "firm spheres and
stuff":

They made good prediction for where the planets are going to be. They covered
all the known planets. They produced accurate results for all the observations
of their time. It took the lifetime work of Brahe and his development of his
own observatories to even collect enough data for Kepler to be able to
recognize differences between the approximate circle paths of the planets.

In short, just like Newton's, Ptolemy's formulas are a "good enough"
approximation when knowing their limits.

I've even read one scientist, and I tend to believe him, claiming that Ptolemy
himself, during the development of his formulas, must have used the Sun-
centric model, and then he produced the "projected" result which was more
acceptable for everybody who just wanted to calculate where the planets are on
the sky, as seen from the Earth.

~~~
riffraff
you misunderstood me, I'd consider the Ptolemaic model "good science" (i.e. it
makes appropriate predictions, and can be improved and falsified, which it
was).

It's just that before the scientific method become common place a lot of
theories weren't.

~~~
acqq
Then we think the same. I didn't reply to you out of the disagreement with
what you wrote, but as the complement.

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nan0
Off topic ,but was Columbus really the discoverer of America?

Follow up article : "Why Christopher Columbus was the Perfect Icon for a New
Nation looking for a Hero" [http://www.smithsonianmag.com/history/why-
christopher-columb...](http://www.smithsonianmag.com/history/why-christopher-
columbus-was-perfect-icon-new-nation-looking-hero-180956887/)

~~~
huherto
Columbus travels changed the world. It is arguably the most important
discovery in human history. Even if the Vickings were first you have to
consider the historical significance.

~~~
metaphorm
> It is arguably the most important discovery in human history

Fire? Writing? Textiles?

There's a case to be made its the most important discovery of his era, but
then, we do tend to be Eurocentric here and the Chinese were at the climax of
a centuries long golden age when Colombus was doing his thing in America.

~~~
huherto
There is a reason we are Eurocentric. That is precisely because Europeans
discovered America. It changed their mindset. They started looking outwards
while the Chinese kept looking inwards. It launched an era of exploration.

Fire, writing and textiles are prehistoric discoveries/inventions.

