Talk:Celestial spheres

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Contents 1 Proposed merger with Sphere (geocentric) 1.1 Merger implemented 2 Unmoved mover 3 Harmonia Mundi 4 Spheres not geocentrist 5 Plato spherist? 6 Was Dante's God simultaneously in two different places? 7 Proposed section on inertia and the celestial spheres

[edit] Proposed merger with Sphere (geocentric)

Comparing these two articles I think a merger is in order. Sphere (geocentric) has a somewhat better overall presentation on the background in Greek philosophy, the Ptolemaic system, and on the literary impact.

The section on Kepler in Celestial spheres is extraneous; it would be better to discuss the continued use of the spheres by Copernicus and their ultimate rejection by Tycho and Kepler.

There is a definite need for a consideration of the philosophical and theological implications, on which Grant spends 670 pages, plus a hundred more of notes.

As for title of the merged article, I'd recommend Celestial spheres or Celestial orbs; but then I'm a medievalist and would look there. --SteveMcCluskey 20:55, 23 January 2007 (UTC)

For the moment, I have begun to edit and expand the two articles into a more coherent and fully documented one here. --SteveMcCluskey 01:53, 24 January 2007 (UTC) (Edited 14:47, 24 January 2007 (UTC))

[edit] Merger implemented

OK, I've rewritten the article; saved it as Celestial spheres; and made Sphere (geocentric) a redirect. There are still some gaps but I think it's an improvement. --SteveMcCluskey 15:37, 25 January 2007 (UTC)

[edit] Unmoved mover

Deor: Recently we've been involved in an edit skirmish -- it certainly hasn't escalated to the level of a war -- involving changes back and forth between the Prime Mover to the Primum Mobile. The changes have improved the precision of the discussion, but I think it would help if we clarified the intent of the paragraph being revised.

The paragraph involved concerns the movers of the spheres, not the spheres themselves. In that context the discussion of the first moving sphere should concentrate on its mover, the Prime Mover (who is, as Aristotle says, unmoved), not on the first moving sphere, the Primum Mobile, itself.

I'm going to revise again to take this approach; I hope it meets your concerns. let me know what you think. SteveMcCluskey 14:58, 17 February 2007 (UTC)

I'm not going to push it any farther. Before I began editing the article, it contained the sentence "The outermost mover, whose movement affected all others, was referred to as the Prime Mover and identified with God," which was clearly muddled, since the whole point of the Prime Mover is that it has no "movement" itself. In an effort to fix that, I seem to have stepped on your toes. I'm still not exactly sure what objection you have to linking the mention of "the first moving sphere" to the Primum Mobile article, but it's not worth arguing about. Deor 15:11, 17 February 2007 (UTC)

Ah; now I see. It was the link to the Primum Mobile that you wanted. I think we've already resolved the muddle you saw and since I've no problem with the link, I've added it now. (It's always hard to understand what's in an other editor's mind.) SteveMcCluskey 18:22, 17 February 2007 (UTC)

[edit] Harmonia Mundi

Why has the reference to Kepler's work Harmonia Mundi been removed?

Johannes Kepler dealt with the concept of the spheres in his work Harmonia Mundi. Kepler drew together theories from the world of music, architecture, planetary motion and astronomy and linked them together to form an idea of a harmony and cohesion underlying all world phenomena and ruled by a divine force.

This work remained untranslated into English for over 400 years, until astronomer and mathematician Dr J. Field translated the Latin into English for publication by the American Philosophical Society in Philadelphia in 1997.

Above removed 25 January 2007 by SteveMcCluskey Lumos3 19:57, 18 February 2007 (UTC)

Two reasons:

• First, the removal was part of a total rewrite of the article. In that rewrite I made it clear that Kepler largely abandoned the idea of the spheres, which he had used in several of his earlier works, not just the Harmonia Mundi. I didn't feel like mentioning all the specific works where he used the spheres. My replacement read:

Although in his early works Johannes Kepler made use of the notion of celestial spheres, by the Epitome of Copernican Astronomy (1621) Kepler was questioning the existence of solid spheres and consequently the need for intelligences to guide the motions of the heavens. An immobile sphere of the fixed stars, however, was a lasting remnant of the celestial spheres in Kepler's thought.

• I thought the paragraph about Field's translation cluttered the body of the article.

Hope this explains my changes. SteveMcCluskey 22:41, 18 February 2007 (UTC)

[edit] Spheres not geocentrist

The current opening paragraph is:

"The celestial spheres, or celestial orbs, were the fundamental element of Earth-centered (geocentric) astronomies and cosmologies developed by Plato, Aristotle, Ptolemy, and others. In these geocentric models the stars and planets are carried around the Earth on spheres or circles."

But it is profoundly misleading in respect of ahistorically tying spherism to geocentrism, historically refuted by the case of Copernicus's heliocentric spherism and geoheliocentric celestial models such as those Wittich and Ursus etc. Also Plato did not propose spheres, but rather mere bands for each planet in his Timaeus. Rather it seems it was Aristotle who first introduced spheres, and instead of mere bands for some reason as yet unexplained. And to say the planets are carried around on circles is obviously both physically absurd and geometrically false re planetary orbital paths. I therefore propose this first paragraph be replaced by the following historically less misleading paragraph:

'The celestial spheres, or celestial orbs, were the fundamental celestial entities of the cosmological celestial mechanics founded by Aristotle and developed by Ptolemy, Copernicus and others. [ref] Before Aristotle, in his Timaeus Plato had previously proposed the planets were transported on rotating bands.[ref] In this celestial model the stars and planets are carried around by being embedded in rotating spheres made of an aetherial transparent fifth element (quintessence), like jewels set in orbs. In Aristotle's original model the spheres have souls and they rotate because they are endlessly searching for love, which is the scientific historical origin of the popular saying 'Love makes the world go round'. Arguably nobody has ever proposed a more beautifully romantic cosmology, or at least until the great Yorkshireman Fred Hoyle proposed we are all made of stardust.'

One potential important function of the last two sentences here is to promote educational interest in the article and the fundamental historical importance and cultural influence of cosmology, and thus interest in physics. In his 2005 Lakatos Award lecture, Patrick Suppes emphasised how the theory of the celestial spheres was the most brilliantly successful longstanding cosmology of all time, but ironically so little understood by historians and philosophers of science, especially including the reasons for its termination.

The current untenable geocentrist bias of the remainder of the article should also be corrected. --Logicus (talk) 19:15, 20 February 2008 (UTC)

Anti-Deor: Deor reverted this edit implemented on 20 Feb, with the mistaken justifying comment "rv edit introducing unsourced info and POV - you should wait for feedback on the Talk page)". But in fact (i) the revised text was no more unsourced than the original and (ii) nor did it introduce a POV, but rather corrected the existing untenable geocentrist biassed POV of the original. And whilst Logicus is happy to await feedback before reverting, and indeed in most instances normally both posts proposed edits for discussion first, unlike most other editors, and also awaits feedback except perhaps where text is apparently unquestionably mistaken, he would be grateful if in future Deor would devote his efforts to reverting all other breaches of the rule he proposes before reverting Logicus's, whose edit Deor reverted just 9 minutes after its implementation. --Logicus (talk) 19:58, 22 February 2008 (UTC)

"Arguably nobody has ever proposed a more beautifully romantic cosmology, or at least until the great Yorkshireman Fred Hoyle proposed we are all made of stardust" was unacceptable POV in more than one respect. And the sentence preceding that one was factually incorrect. Deor would be grateful if Logicus eschewed personal comments. Deor (talk) 21:23, 22 February 2008 (UTC)

Logicus to Deor:I would be grateful to know what you claim is factually incorrect in "the sentence preceding", and why. It is

"In Aristotle's original model the spheres have souls and they rotate because they are endlessly searching for love, which is the scientific historical origin of the popular saying 'Love makes the world go round' "

Re personal comments, Logicus has not made any personal comments about you, but you issued the following very personal dictatorial instruction to Logicus: "YOU should wait for feedback on the Talk page."

I propose to implement at least the uncontested part of the proposed edit pro-tem whilst you explain the alleged error in the following sentence, supplemented with a diagram of a heliocentric model of celestial orbs to correct the historically untenable geocentrist bias.--Logicus (talk) 19:59, 23 February 2008 (UTC)

I would be grateful to know what you claim is factually incorrect in "the sentence preceding." No problem: "Endlessly searching for love" is a misrepresentation of what Aristotle wrote ("endlessly moved by their love for the Unmoved Mover" would be more accurate), and the extremely unlikely "is the scientific historical origin of the popular saying 'Love makes the world go round'" is unacceptable without some source other than your say-so. Deor (talk) 15:57, 24 February 2008 (UTC)

[edit] Plato spherist?

Notwithstanding its comments on the Spindle of Necessity, the Sirens and the Fates, the following current claim:

"One of the earliest intimations of celestial spheres appears in Plato's "Myth of Er," a section of the Republic, which describes the cosmos as the Spindle of Necessity, attended by the Sirens and turned by the three Fates."

does not actually evidence Plato was a spherist, rather than merely a bandist as in Timaeaus.

Unless Plato's alleged spherism can be documented, I propose its deletion.--Logicus (talk) 15:13, 24 February 2008 (UTC)

[edit] Was Dante's God simultaneously in two different places?

The article currently claims:

"Near the beginning of the fourteenth century Dante, in the Paradiso of his Divine Comedy, described God as a light at the center of the cosmos.[15]. Here the poet ascends beyond physical existence to the Empyrean Heaven, where he comes face to face with God himself and is granted understanding of both divine and human nature."

Is this contradictory ? i.e. was God both at the centre and also in the Empyrean Heaven at the same time ? Or is his light at the centre and his face in Heaven ?

This is not a frivolous issue. If both human beings (e.g. Scipio) and/or also God can ascend through the spheres or interpenetrate them, then why not comets also ? --Logicus (talk) 15:22, 24 February 2008 (UTC)

As you probably know, God isn't in any "place"; note "beyond physical existence" in the sentences you've quoted from the article. As C. S. Lewis wrote: "All this time we are describing the universe spread out in space; dignity, power and speed progressively diminishing as we descend from its circumference to its centre, the Earth. But I have already hinted that the intelligible universe reverses it all; there the Earth is the rim, the outside edge where being fades away on the border of nonentity. … [refers to the passage in Dante referred to in the article] The universe is thus, when our minds are sufficiently freed from the senses, turned inside out."

What this has to do with the penetrability or nonpenetrability of the physical spheres (which Dante himself has already passed through to reach the Empyrean) is, to say the least, unclear. Deor (talk) 16:09, 24 February 2008 (UTC)

[edit] Proposed section on inertia and the celestial spheres

Logicus proposes the following text be added to the end of the current 'Middle Ages' section. Another user has deleted a previous posting of it with the clearly mistaken justification that it is irrelevant.

I agree that it's irrelevant in this article. You may want to add some of it (with better sourcing) to the appropriate sections of Inertia. Deor (talk) 15:47, 14 June 2008 (UTC)

---

The crucial notion of inertia as an inherent resistance to motion in bodies that was to become the central concept of Kepler's and then Newton's dynamics in the 17th century first emerged in the 12th century in Averroes' Aristotelian celestial dynamics of the spheres to explain why they do not move with infinite speed and thus avoid the refutation of Aristotle's law of motion v @ F/R by celestial motion (where v = average speed of a motion, F = motive force and R = resistance to motion). For in Aristotle's celestial mechanics the spheres have movers but no external resistance to motion such as a resistant medium nor any internal resistance such as the gravity or levity of sublunar bodies that resist 'violent' motion, ^[1] and hence whereby R = 0 but F > 0, and so speed must be infinite. But yet the fastest sphere of all, the stellar sphere, observably takes 24 hours to rotate. In the 6th century Philoponus had sought to resolve this devastating celestial empirical refutation of mathematical dynamics by rejecting Aristotle's core law of motion and replacing it with the alternative law v @ F - R, whereby a finite force does not produce an infinite speed when R = 0.^[2]

But Averroes rejected Philoponus's 'anti-Aristotelian' solution to this celestial counterexample, and instead restored Aristotle's law of motion by adopting the 'hidden variable' approach to apparent refutations of parametric laws that posits a previously unaccounted variable and its value for some parameter. For he posited a non-gravitational previously unaccounted inherent resistance to motion hidden in the spheres, a non-gravitational inherent resistance to motion of superlunary quintessential matter. Thus Averroes most significantly transformed Aristotle's law of motion v @ F/R into v @ F/M for the special case of celestial motion with his auxiliary theory of what may be called celestial inertia M. However, Averroes denied sublunar bodies have any inherent resistance to motion other than their gravitational (or levitational) inherent resistance to violent motion.

But Averroes’ 13th century disciple Thomas Aquinas rejected this denial and extended this development in celestial physics to sublunar bodies,^[3]whereby he claimed this non-gravitational inherent resistance to motion of all bodies would also prevent infinite speed of gravitational motion of sublunar bodies in a vacuum, as predicted by the law of pre-inertial Aristotelian dynamics in one of Aristotle's famous examples of the impossibility of motion in a vacuum (i.e. a void with gravity), in which the variant of the law for the special case of natural motion v @ W/R thus became v @ W/0. ^[4] But it was Kepler who first dubbed this non-gravitational inherent resistance to motion in all bodies universally 'inertia', and Newton who revised it to exclude resistance to uniform straight motion, a purely ideal form of motion.^[5] Thus the notion of the resistant force of inertia was born in the heavens of medieval astrophysics, in the Aristotelian physics of the celestial spheres, rather than in terrestrial physics or in experiments. This auxiliary theory of inertia originally devised to account for the motions of the celestial spheres was the most important development in Aristotelian dynamics in its second millenium of progress in its core law of motion towards the quantitative law of motion of classical mechanics a @ (F - R)/m by providing its denominator, whereby acceleration is not infinite when there is no other resistance to motion.

--Logicus (talk) 14:52, 14 June 2008 (UTC)