This is a blog to discuss philosophy, chess, politics, C. S. Lewis, or whatever it is that I'm in the mood to discuss.
Sunday, October 07, 2018
Large-earthers and small-earthers
Actually, the idea that people who were critical of Columbus were flat-earthers is a well-known historical mistake. Everyone knew the world was round. There were two types of people, those like Columbus whom we might call small-earthers who thought you could get to the Indes after a relatively short trip, and large-earthers, who thought there was a large ocean to cross and that it would not be cost-effective to have lots of ships sailing West to get to the East. The large-earthers were right, of course, but Columbus made it into the history books because there was this other continent between Europe and Asia on the Westward route, what eventually became know as the Americas.
Not a subject I'm studied on, but couldn't the issue be resolved by using the curvature of the horizon to figure out the circumference? Or was that beyond their capabilities at the time?
ReplyDeleteLegion of Logic,
ReplyDeleteIt's hard to measure curvature without a reliable way to measure large distances. For example, if I assume a sphere, and see the mast of a ship whose height from the ocean floor I know is 20', I get different curvatures if it disappears five miles from shore or 5.1 miles from shore, but I don't have a good way (at that time) to know which of them is correct.
The diameter of the Earth was actually determined with astonishing precision by the Greek mathematician Eratosthenes in 240 BC. He arranged for people to make precise measurements of the shadows of sticks of identical lengths at the same moment in time at varying latitudes (from northern Greece to southern Egypt). By calculating the difference in shadow length from one latitude to another, he was able to determine the curvature of the Earth, and thus its diameter.
ReplyDeleteThese experiments were well known in Columbus's time, so my only conclusion is that he willfully ignored them in order to gain support for his otherwise insane idea of sailing west to reach the Indies.
By the way, replicating Eratosthenes' experiment is a popular international science activity of contemporary school children. Students from places as far apart as England and Ghana or Canada and Ecuador will measure the length of shadows at noon of the same day and from them find the size of the Earth.
This sounds about right to me. Read the one with the green checkmark.
ReplyDeleteAs so often, when foolish decisions are made there are politics involved.
By the way, I am in awe of the Greeks' ability to have people thousands of miles apart conduct the exact same experiment at the exact same time - and all without any means of communication faster than a horse.
ReplyDeleteBoggles the mind.
Blogger Starhopper said...
ReplyDeleteThe diameter of the Earth was actually determined with astonishing precision by the Greek mathematician Eratosthenes in 240 BC. He arranged for people to make precise measurements of the shadows of sticks of identical lengths at the same moment in time at varying latitudes (from northern Greece to southern Egypt). By calculating the difference in shadow length from one latitude to another, he was able to determine the curvature of the Earth, and thus its diameter.
These experiments were well known in Columbus's time, so my only conclusion is that he willfully ignored them in order to gain support for his otherwise insane idea of sailing west to reach the Indies.
There were other calculations made, contemporaneously and later, that produced numbers about 3/4 the estimate of Eratosthenes, but it is also true that Columbus seems to have distorted the numbers to make them even smaller.
Since the journey by all accounts should have failed, but didn't, it must have been Divine Providence.
ReplyDeleteOn Metarock's blog doing a series on liberal theology and how to distinguish it from other kinds, Informative not arguig for either side.
ReplyDeleteRitschl was in line with Schleiermacher's thinking, he believed religion was primarily a matter of revelation and personal experience. He worked agaisnt Hegel and his ilk in ridding theology of speculative metaphysics and philosophical frameworks. This puts him in line with Schleiermacher since Hegel hated Schleiermacher (the two had been class mates in college) and Schleiermacher's feeling of utter dependence worked directly against Hegel's notions of philosophical speculation. Ritschl sees theology as practical and not speculative. He grounds his inquiry in historical criticism and history, and in the revelation of God through Jesus Christ.
part 1 was Monday was Schleiermacher
ReplyDeleteThis is a very important Clarice abouit the new study on global warming by the UN,We have only 12 years to act and Trump will prevent us using that time effectively. This is of extreme importance, please copy and send this to all your friends use this research to make your own arguments own ,we must win the mid terns,
Trump screws our last chance
that auto correct makes me so angry. This is a very important Clarice> Important essay!
ReplyDeleteIn 1989 we were told we only had ten years. In 2006 we were told we only had 10 years. In 2007 we were told we only had 8 years, or 4 years depending on who you listened to. In 2009 we were told we only had 4 years.
ReplyDeleteThese predictions have been remarkably consistent in being wrong. I wonder if I should treat this one differently?
Legion of Logic said...
ReplyDeleteIn 1989 we were told we only had ten years. In 2006 we were told we only had 10 years. In 2007 we were told we only had 8 years, or 4 years depending on who you listened to. In 2009 we were told we only had 4 years.
These predictions have been remarkably consistent in being wrong. I wonder if I should treat this one differently?
If you look at the actual predictions, and what they were trying to avoid, they've been remarkably accurate.
I agree with One Brow. Contra what legion wrote, the predictions of climatologists have so far been scarily accurate.
ReplyDeleteWho said we had only 10 years and/or what did they mean?
ReplyDeleteOr I could repeat the same... predictions have been surprisingly accurate and models keep being refined.
It's like the myth of "they used to predict an ice age!" when, in reality, scientists have been seeing warming trends, and giving warnings, for decades.
For anyone interested in the topic; this ex science journalist has been making videos to make the content accessible to all for many years:
ReplyDeletehttps://www.youtube.com/playlist?list=PL82yk73N8eoX-Xobr_TfHsWPfAIyI7VAP
by potholer54
Haha well okay.
ReplyDelete
ReplyDeletePolitics is not an expression of the Gospel but the values of or politics should be taken the values that are derived from our theology, If not we are inconsistent with our beliefs, The Gospel mandates the value of social justice, The conservatives and right have taught Americans to dispirit the notion of social justice but it is at the heart of the Gospel,
Metacrock's blog: Gospel mandates Value Social Justice
Joe Hinman said...
ReplyDeletethat auto correct makes me so angry. This is a very important Clarice> Important essay!
October 11, 2018 11:12 PM Delete
Blogger Legion of Logic said...
In 1989 we were told we only had ten years. In 2006 we were told we only had 10 years. In 2007 we were told we only had 8 years, or 4 years depending on who you listened to. In 2009 we were told we only had 4 years.
These predictions have been remarkably consistent in being wrong. I wonder if I should treat this one differently?
people come on face book and say this all the time it is absolute drivel. No credible scientific study said that, this is a UN study.Since 1989 a lot of people have said a lot of things. That should not cancel out scientific studies when they are done,,
my article presets quite it of research, That right wing ploy about they keep saying that is just nonsense, who said what? turn on then light man.
ReplyDelete