Talk:De sphaera mundi

Earlier article

For earlier discussion related to a now-deleted article on this book, see Talk:Sphaera Mundi.

The deleted article was the subject of a dispute regarding whether the author was entitled to insist on attribution to another wiki. I did not rely on that article for any of the information I used to create this one, so the issue is now moot. Frankly, the article was of poor quality in any case, as it focused on a specific edition of the book (and not even the first printing), rather than being about the book itself.

From the previous discussion and my brief research, it remains unclear what the most common title of the book is, as it carried several in its various editions. Although "De sphaera mundi" gives it the real flavor of astronomy, it may be that plain "De sphaera" is more accurate. Anyone who wants to pursue this further should probably get their hands on The Sphere of Sacrobosco and its Commentators by Lynn Thorndike, which was mentioned earlier and would probably make a great start to building a "References" section. --Michael Snow 05:33, 15 August 2005 (UTC)

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as stub, and the rating on other projects was brought up to Stub class. BetacommandBot 03:30, 10 November 2007 (UTC)

OR

I marked the claim that this book proves that the belief that "13th century people were mostly Flat Earthers is wrong" as original research. We need a secondary source that makes such an attribution. For example, just because this one book did not hold to a Flat Earth perspective, does not rule out the possibility that others did. Now, if a reliable secondary source says, "De sphaera mundi shows us that the belief in the 19th century that...", then we can attribute that and give a reference. Absent such sourcing, though, the info should probably be removed. Qwyrxian (talk) 00:18, 29 July 2011 (UTC)

The principal secondary source is no doubt Jeffrey Burton Russell, Inventing the Flat Earth. He stated in his summary [1] that he could find only two to five early Christian fathers who denied a spherical Earth but "On the other side tens of thousands of Christian theologians, poets, artists, and scientists took the spherical view throughout the early, medieval, and modern church." and "No one before the 1830s believed that medieval people thought that the earth was flat." So De sphaera mundi would have been only one example in a long list of medieval sources refuting the late 19th- and early 20th-century view "that medieval scholars from the 13th century thought the Earth was flat". See Myth of the Flat Earth. However, I cannot provide a citation that specifically mentions De sphaera mundi until I consult Russell. — Joe Kress (talk) 19:43, 31 July 2011 (UTC)

I'm adding the promised reference. — Joe Kress (talk) 07:01, 2 August 2011 (UTC)

Excellent, thanks! Qwyrxian (talk) 07:14, 2 August 2011 (UTC)

Sabrosco does not teach a sperical earth

Contrary to what this article says, Sabrosco makes statements that contradict a spherical earth, for example is he saying in Chapter 1:

Those are said to have the sphere oblique who live this side of the equator or beyond it. For to them one pole is always raised above the horizon, and the other is always depressed below it.

If people in Europe have one pole raised above the horizon, the earth cannot be a sphere because on a sphere neither pole is raised above the horizon unless you live at the pole itself. This disproves the idea that Sabrosco portrayed a spherical earth.

Furthermore the section that is quoted where Sabrosco is supposed to be saying that the earth is a sphere is misrepresented. He says that the earth is round, not a sphere:

That the earth, too, is round is shown thus.

The English section heading "THE EARTH A SPHERE" is an addition and not contained in the original Latin. What he does say in this section, is that the earth has a "swelling" or bulge (Latin "tumor"):

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. 

I'm quite sure that more proof could be found in the document against the matter but I suppose that this enough to convince anyone sensible enough not to follow the interpretations given on this wiki page. — Preceding unsigned comment added by Retonom (talk • contribs) 12:59, 3 April 2024 (UTC)

It looks to me like you are entirely misunderstanding Sacrobosco's point, which is that people who don't live on the equator always have one pole of the celestial sphere visible. These statements would be very confusing if not meaningless if the Earth were not roughly spherical. –jacobolus (t) 21:49, 3 April 2024 (UTC)

Granted, I'll mark this part of my objection as invalid, but the rest of my argument stands and you have not addressed it. The article's section "Spherical Earth" and statements made there like "De sphaera 1230 A.D. contains a clear description of the Earth as a sphere" are incorrect. Sabrosco's work does not contain a clear description of the Earth being a sphere. It doesn't mention the earth being a sphere at all. Retonom (talk) 06:59, 5 April 2024 (UTC)

I don't really understand what you are getting at. The sphericity of the Earth was obviously well understood by scholars (including Sacrobosco) since at latest Eudoxus in the 4th century BC. Ptolemaic astronomy, including Sacrobosco's work, is premised on having a spherical Earth, which was taken for granted as an obvious fact. (To the extent that belaboring it in this article seems kind of unnecessary.) –jacobolus (t) 07:29, 5 April 2024 (UTC)

Here's a direct quotation of an English translation of De Sphaera:

The Earth a Sphere.—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.

Further Proofs of This.—That the earth also has a bulge from north to south and vice versa is shown thus: To those living toward the north, certain stars are always visible, namely, those near the [celestial] North Pole, while others which are near the South Pole are always concealed from them. If, then, anyone should proceed from the north southward, he might go so far that the stars which formerly were always visible to him now would tend toward their setting. And the farther south he went, the more they would be moved toward their setting. Again, that same man now could see stars which formerly had always been hidden from him. And the reverse would happen to anyone going from the south northward. The cause of this is simply the bulge of the earth. Again, if the earth were flat from east to west, the stars would rise as soon for westerners as for orientals, which is false. Also, if the earth were flat from north to south and vice versa, the stars which were always visible to anyone would continue to be so wherever he went, which is false. But it seems flat to human sight because it is so extensive.

Surface of the Sea 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 theeye 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. For all other impediments are excluded, such as clouds and rising vapors.

You can see the drawings accompanying a 1501 printed edition copy in this scan: https://archive.org/details/sphaeramundi00sacr_0/page/n19/mode/2up

There is a picture of a round earth with little people standing on it pointing outward in different directions, with different stars visible to them because of the Earth's sphericity. It is not remotely supportable to claim that "Sabrosco [sic] does not teach a sperical [sic] earth". –jacobolus (t) 07:56, 5 April 2024 (UTC)

Again I say the same. Sabrosco is talking about a bulge, and he's not saying it's a sphere. The titles mentioning a sphere are added in the English version and are not original. And the picture you are talking about, if you watch closely, the little people do not stand on the earth but are walking, sitting or crawling on the lines drawn. Retonom (talk) 08:21, 5 April 2024 (UTC)

One of the manuscript sources has something like "On the roundness of the Earth" as an added heading here.

But anyway, what do you think Sacrobosco means when he says that the Earth is "round" and has a "bulge" in both the East–West and North–South directions?

What do you think Sacrobosco means when he says the oceans are round like a water droplet?

What do you think Sacrobosco means when he says we can measure the "girth" of the Earth by first measuring the terrestrial length of 1° by taking a star sighting then walking northward until stars move the expected amount, then multiply this length by 360, and then goes on to say we can find the Earth's diameter by following the rule for circles?

Are you getting this weird criticism from some particular source? Some flat earth conspiracists or something? –jacobolus (t) 08:41, 5 April 2024 (UTC)

All I'm saying is that he doesn't say the earth is a sphere as the article postulates. We could go on an debate whether he meant the earth to be a sphere but he doesn't say it, so the article shouldn't say he did. Ok? Retonom (talk) 11:05, 10 April 2024 (UTC)

I disagree, as do the published works by experts in this topic. Maybe you can find "reliable sources" claiming that Sacrobosco did not think the Earth was spherical? –jacobolus (t) 19:37, 11 April 2024 (UTC)

In the middle ages they didn't believe in the spinning ball

As pointed out above the whole section "Spherical Earth" should be removed because it is not factual. This part is also incorrect:

... which agrees with widespread opinion in Europe during the higher Middle Ages, in contrast to statements of some 19th- and 20th-century historians that medieval scholars thought the Earth was flat.

I can give two important proofs that the Copernicus and people like him were regarded as fools in the middle ages. Both Martin Luther and John Calvin condemned these theories and it can be seen from their comments, that the idea of the earth being a spinning sphere was laughable at this time. The historians in the 19th- and 20th century were correct and this new teaching is not.

Calvin's account:

And let us not be similar to those dreamers, who have a spirit of bitterness and contradiction, who reprove everything and pervert the order of nature. We will see some so deranged, not only in religion, but who demonstrate in all things that they have a monstrous nature, that they will say that the sun does not move, and that it is earth that moves and turns. When we see such minds, it must be said that the devil possess them, and may God set them before us as mirrors, to make us remain in his fear.

from Sermon 8 on 1 Corinthians 10:19—24 (translated from French), Joannis Calvini opera quae supersunt omnia, Volume 49, page 677

And here's what Martin Luther had to say about it:

It was thought of a new astrologer [meaning Copernikus], who wanted to prove that the earth would be moving and going around, not the sky or the firmament, the sun and the moon; Just as if someone is sitting and moving in a car or in a ship, would say that he was sitting quietly and calm, but the earth and the trees went around and moved. But nowadays it works like that: who wants to be clever should not have pleasure in what others do, he has to create something of his own, and it has to be the very best, the way he makes it. The fool wants to reverse the whole art of astronomy. But as the Holy Scripture shows, Joshua called the sun to stand still and not the earth. Joshua 10.12-13.

from Martin Luther, Colloquia Oder Tischreden, Chapter LXX "Von der Astrologia", page 433, Issued 1568 Google Books — Preceding unsigned comment added by Retonom (talk • contribs) 05:11, 11 April 2024 (UTC)

You are mixing up two different things: (1) whether the Earth revolves around the sun and spins (the "Copernican" theory, which was controversial at the time) vs. the Earth being fixed with the stars and sun revolving around the earth, and (2) whether the Earth is spherical (accepted as an obvious fact by all astronomers and other educated people from the 4th century BC to the present). –jacobolus (t) 19:34, 11 April 2024 (UTC)

Medival Scholars

In the aspect of the Article that "medieval scholars thought the Earth was flat," medieval scholars don't exist. We don't know who 'medieval scholars' are because it is a collective. 2600:1700:9B01:1A0:51E9:F617:EA76:8350 (talk) 06:14, 19 May 2024 (UTC)