[QUOTE=yabob]
One thing I find curious is that the existence of another land mass should have been a complete surprise to everybody. Surely, using the roughly correct figures and estimating the ocean distance to Japan at 10000 miles, somebody must have entertained the possibility that in all that unexplored ocean there might be at least a sizeable island that nobody knew about, or maybe even a whacking great continent or two.
[/QUOTE]
Possibly, but would you have staked your life on it? Because, that is what we are talking about after all.
[QUOTE=John Mace]
I’m skeptical that this is generally accepted by scholars of the subject. Can we have some cites?
[/QUOTE] The Worlds of Christopher Columbus (1993), by William D. Phillips, Jr. and Carla Rahn Phillips:
[QUOTE=yabob]
One thing I find curious is that the existence of another land mass should have been a complete surprise to everybody. Surely, using the roughly correct figures and estimating the ocean distance to Japan at 10000 miles, somebody must have entertained the possibility that in all that unexplored ocean there might be at least a sizeable island that nobody knew about, or maybe even a whacking great continent or two.
[/QUOTE]
Actually, if you go back a few hundred million years, all of the continents were combined together in one continuous mass. This has happened more than once, and is projected to happen again.
Plate tectonics tends to cause the continents to all bang into each other, to separate, and to eventually run into each other again.
If we humans had lived in a time in Earth’s geologic history when the continents were stuck together, Columbus would probably not have made it all the way around the long way. (Unless he was lucky enough to run into a volcanic island chain like Hawaii…)
[QUOTE=yabob]
One thing I find curious is that the existence of another land mass should have been a complete surprise to everybody. Surely, using the roughly correct figures and estimating the ocean distance to Japan at 10000 miles, somebody must have entertained the possibility that in all that unexplored ocean there might be at least a sizeable island that nobody knew about, or maybe even a whacking great continent or two.
[/QUOTE]
There were many rumors and legends of islands in the Atlantic, including the Isle of Brasil (Hy-Brasil), after which the present Brazil was named after its discovery in 1500, and Antillia, after which the Antilles were named after their discovery by Columbus. As I mentioned, Columbus gathered all the “information” he could on these mythical islands before setting out.
[QUOTE=Colibri]
That’s correct, but I think you miss the point of Lemur’s post a little. The circumference of the world was directly relevant to whether the western route to Asia was feasible or not. Columbus believed the circumference of the world to be 25% smaller than that calculated by Eratosthenes in 200 BC, which was actually almost correct; and 10% smaller than that calculated by Ptolemy. At the same time, he believed that Asia stretched much further west than the classical geographers had. The result of these two miscalcualtions was that Columbus thought the west coast of Asia was within striking distance of Europe, which it was not. So settling the scientific dispute in Columbus’ favor was essential to the feasibility of the western route.
[/QUOTE]
Why didn’t he believe them? The Greeks were considered to be fairly authoritative on such calculations, no? So where did Columbus come up with his numbers and what made him believe they were more accurate than anyone else’s estimates?
[QUOTE=TJdude825]
Why didn’t he believe them? The Greeks were considered to be fairly authoritative on such calculations, no? So where did Columbus come up with his numbers and what made him believe they were more accurate than anyone else’s estimates?
[/QUOTE]
It was apparently a combination of wishful thinking (or perhaps just PR), cherry-picking the most optimistic estimates from antiquity, and confused translations of ancient sources. See here for a brief discussion.
[QUOTE=TJdude825]
Why didn’t he believe them? The Greeks were considered to be fairly authoritative on such calculations, no? So where did Columbus come up with his numbers and what made him believe they were more accurate than anyone else’s estimates?
[/QUOTE]
Well, as mentioned above, even the Greeks didn’t exactly agree (Erasthones vs. Ptolemy) on the size of the Earth. And the breadth of Asia wasn’t known very well at all. Columbus was the eternal optimist who chose the most favorable numbers for all of his calculations. For a good sci-fi take on why this was, read Orson Scott Card’s Pastwatch.
BTW, Eratosthenes got lucky, too. His technique was sound, but his assumptions and the accuracy of data available to him were not good enough to assure him coming as close as he did. For one thing, he assumed Alexandria was due north of Syene (present day Aswan). It is, in fact, a significant distance west. Syene is not exactly on the Tropic of Cancer, either, so the sun was not really directly overhead there at the summer solstice, as he assumed. Errors in the distance measurements he had available apparently compensated, rather than accumulating, allowing him to come up with a surprisingly accurate figure. It would still have been a noteworthy accomplishment if he had come within, say, 10 or 20% of the correct figure, as might have been expected given the tools and data he had available.
[QUOTE=Colibri]
That’s correct, but I think you miss the point of Lemur’s post a little.
[/QUOTE]
no, I understood perfectly. His post gave the impression that columbus sailed with the sole purpose of testing the size of the Earth. And that’s not correct, is it? It would be more correct to say that he made an assumptionm about the size of the arth, one that turned out to be wrong. Proving a point was never part of the mission.
[QUOTE=Peter Morris]
no, I understood perfectly. His post gave the impression that columbus sailed with the sole purpose of testing the size of the Earth. And that’s not correct, is it? It would be more correct to say that he made an assumptionm about the size of the arth, one that turned out to be wrong. Proving a point was never part of the mission.
[/QUOTE]
I don’t see how Lemur’s post indicated that that was the sole point of the mission - that’s your own interpretation. **Lemur ** said nothing in his post about Columbus’s motivations. Columbus’s miscalculations were the reason he thought the trip was possible, and were essential to his even attempting it. If Columbus had reached Asia in 4000 miles, that would have proved his conjecture, and thus it was an implicit part of the mission.
Of course Columbus didn’t care about the circumference of the earth.
He had the idea to sail west to reach the Indies. He really really really wanted this to be possible. So he chose numbers that would make a voyage west to the Indies possible rather than suicide. But those numbers were all wrong, Columbus only believed them because they supported his mission.
He didn’t decide it was possible to reach the Indies because he believed the Earth was small, rather he decided the Earth was small because he believed it was possible to reach the Indies.
[QUOTE=Colibri]
I don’t see how Lemur’s post indicated that that was the sole point of the mission - that’s your own interpretation. **Lemur ** said nothing in his post about Columbus’s motivations.
[/QUOTE]
The specific words were “However, Columbus maintained that the earth’s circumference was something like 15,000 miles, while the philosophers maitained it was 28,000 miles. The philosophers were right, Columbus was wrong.”
I have this image: Philosopher: You’re mad, Columbus, mad I tell you. Columbus: Fool. I’ll show you. I’ll show you all. Bwah-ha-ha-ha.
[QUOTE=Peter Morris]
The specific words were “However, Columbus maintained that the earth’s circumference was something like 15,000 miles, while the philosophers maitained it was 28,000 miles. The philosophers were right, Columbus was wrong.”
[/quote]
That is of course completely true. What was your point again?
You have a fine imagination. This isn’t of course related to anything that **Lemur ** said.
Columbus: “I can sail west to the Indies!”
Philosophers: “He’s mad, my Lady! Our calculations show it would be a trip of 10,000 miles. He’ll never make it.”
Columbus: “Fools! MY calculations show it would be a trip of only 4,000 miles! I shall return with the riches of the Indies and destroy you all!”
[QUOTE=Colibri]
That is of course completely true. What was your point again?.
[/QUOTE]
:rolleyes: The point is that he *seemed *to be saying that Columbus made his voyage in order to settle this dispute,
Okay, so in fact he wasn’t actually saying that. I accept that this isn’t what he meant to say at all. But it is the most obvious interpretation of his words, albeit a wrong one.
[QUOTE=Peter Morris]
:rolleyes: The point is that he *seemed *to be saying that Columbus made his voyage in order to settle this dispute,
Okay, so in fact he wasn’t actually saying that. I accept that this isn’t what he meant to say at all. But it is the most obvious interpretation of his words, albeit a wrong one.
[/QUOTE]
I don’t think it’s an obvious interpretation, either. Lemur was just giving the aspect of the story that was most relevant to the OP; he wasn’t trying to give the entire story.
Well, when you jump out of a plane, you are in practice testing the theory that your parachute will work. But the fact that you were willing to jump indicates you’ve already formed a strong conclusion on the outcome of the test.