Early Arabic Critique of Ptolemaic Cosmology: A Ninth-Century Text on the Motion of the Celestial Spheres

See, for example, Hartner Willy , “Copernicus the man, the work, and its history”, Proceedings of the American Philosophical Society, cxvii (1973), 413–22, reprinted in his Oriens occidens II (Hildesheim, 1984), 251–60; idem, “Astronomy from Antiquity to Copernicus”, Oriens occidens II, 326–32; idem, “The Islamic astronomical background to Nicholas Copernicus”, Oriens occidens II, 316–25; Swerdlow Noel , “The derivation and first draft of Copernicus's planetary theory: A translation of the Commentariolus with commentary”, Proceedings of the American Philosophical Society, cxvii (1973), 423–512; Swerdlow Noel and Neugebauer Otto , Mathematical astronomy in Copernicus's De revolutionibus (New York, 1984), 41–48, 193, 295, et passim; and finally Saliba George , “Arabic astronomy and Copernicus”, Zeitschrift fur Geschichte der Arabisch-Islamischen Wissenschaften, i (1984), 73–87.

I have attempted to sketch the developments in Arabic planetary theories in the introduction to A history of Arabic astronomy: Planetary theories during the Golden Age of Islam (New York, 1994).

As far as I can tell, the term ‘Marāgha School’ was first coined by Roberts Victor , “The planetary theory of Ibn al-Shāṭir: Latitudes of the planets”, Isis, lvii (1966), 208–19, p. 210, and was codified by Kennedy in “Late medieval planetary theory”, Isis, lvii (1966), 365–78, p. 365, et passim. The name Marāgha refers to the observatory that was built in 1259 (all dates are given in the era A.D. unless otherwise stated) by the Ilkhanid rulers in the north-western city of Iran with the same name. For an excellent study of this observatory in the context of general Islamic observatories, see Sayih Aydin , The observatory in Islam and its place in the general history of the observatory (Ankara, 1960). The term ‘Marāgha School’ is now used more and more in the secondary literature, as can be noted in Encyclopedia of Islam, 2nd edn, iii, s.v. “ilm al-hay'a”, 1135–8, esp. p. 1137, where it designates the work of a group of astronomers who were critical of Greek Ptolemaic astronomy and whose works were similar to those of Copernicus.

Hartner , “Copernicus” (ref. 1), claimed a direct borrowing by Copernicus of the mathematical theorem now known as the Tūsī Couple, which was named after the chief Marāgha astronomer Naṣīr al-Dīn al-Ṭūsī (d. 1274). Hartner even claimed that the alphabetic designations of the geometric points in the theorem as used by Copernicus were identical to the ones used by Ṭūsī with the obvious phonetic transcription of Arabic phonemes into their Latin counterparts.

See, for example, Swerdlow and Neugebauer , op. cit. (ref. 1), for a full documentation.

Sabra A. and Shehaby N. , Ibn al-Haytham: Al-Shukūk 'alā Baṭlamyūs (Dubitationes in Ptolemaeum) (Cairo, 1971).

See, for example, Sabra A.I. , “The Andalusian revolt against Ptolemaic astronomy”, in Transformation and tradition in the sciences, ed. by Mendelsohn Everett (Cambridge, 1984), 133–54, p. 134.

Roberts Victor , “Solar and lunar theory of Ibn al-Shāṭir: A pre-Copernican Copernican model”, Isis, xlviii (1957), 428–32.

According to one historian of science, this age of decline must have begun even earlier, sometime during the eleventh century, for he calls the ninth and the tenth centuries “The Golden Age”. See Smith David E. , History of mathematics (New York, 1958), i, 177.

Saliba George , “The astronomical tradition of Marāgha: A historical survey and prospects for future research”, Arabic sciences and philosophy, i (1991), 67–99.

Introduction, A history of Arabic astronomy (ref. 2).

This is best expressed as such in Ptolemy's Planetary hypotheses, and in the preface to the Almagest. For the Planetary hypotheses, see, for example, Goldstein Bernard , The Arabic version of Ptolemy's Planetary hypotheses, Transactions of the American Philosophical Society, n.s. lvii (1967), no. 4, p. 38 where Ptolemy says: “But we should not attribute to the ethereal bodies (al-ajsām al-athīrīyd) things which we have to posit for the bodies that are around us (fīmā 'indanā min al-ajsām), nor should we imagine of anything that hinders the things which are around us that it would similarly hinder the celestial nature which is completely different from (the things around us) both in essence and in action (fī al-jawhar wa-l-fi'l jamī'an).” In the Almagest Ptolemy says: “… this kind of activity, somewhere up in the highest reaches of the universe, can only be imagined, and is completely separated from perceptible reality”, translated by Toomer G. , in Ptolemy's Almagest (New York, 1984), 35–36. The previous sentence in the Almagest's preface, which is also quoted by the ninth-century text, puts the first celestial motion in the hands of a deity, for it says: “Now the first cause of the first motion of the universe, if one considers it simply, can be thought of as an invisible and motionless deity”, ibid., 35.

See, for example, Kuhn Thomas , The Copernican Revolution: Planetary astronomy in the development of Western thought (New York, 1959), 43–44, 121, et passim.

The first word in the title of Shīrāzī's text has been in dispute for some time. A. I. Sabra argues, in “Ibn al-Haytham's treatise: Solution of difficulties concerning the movement of Iltifāf”, Journal for the history of Arabic science, iii (1979), 388–422, p. 391, note 9, that the word should be read “fa'alta” (“You've done it”, i.e. “You have asked for it”) not “fa'altu” (“I did what I had to do”) as I have read here. Although he does not say so, Sabra may have been following Krause Max , “Stambuler Handschriften Islamischer Mathematiker”, Quellen und Studien zur Geschichte der Mathematik, Astronomie und Physik, Abteilung B, Band 3, Heft 4 (1936), 437–532, p. 508, who also read “fa'alta” (“Du hast (es) getan”). I have argued against this reading in “Ibn Sīnā and Abū 'Ubayd al-Jūzjānī: The problem of the Ptolemaic equant”, Journal for the history of Arabic science, iv (1980), 376–403, p. 377, note 6, to which I can now add that the copyist of Shīrāzī's text, now preserved at Topkapi Seray (Ahmed III, 3338), has clearly vocalized the text in the dedication title page as “fa'altu”. As for the date of the composition of Shīrāzī's text, the colophon of the copy at Topkapi Seray, Ahmad III, 3338 (fol. 126r) is dated 11 Shawwāl 705 A.H. = 25 April 1306. Another manuscript may have had an earlier date for according to Max Krause, op. cit., this text was composed in 704 A.H., i.e. 1304/5. This text of Shīrāzī, which is very important for the history of Arabic astronomy, has not yet been edited, nor has it been fully exploited for the historical information it contains, although it exists in several manuscripts. The edition appended here uses two of these manuscripts to establish the now lost ninth-century text under discussion. I have had occasion to quote this remarkable text of Shīrāzī in connection with another citation from an eleventh-century text by the famous Bīrūnī (d. c. 1050), which is also apparently lost. See Saliba , “The astronomical tradition of Marāgha” (ref. 10).

This commentary is called Nihāyat al-Idrāk fī Dirāyat al-Aflāk (“The final grasp in comprehending the celestial orbs”).

The new commentary was called al-Tuḥfa al-Shāhīya (“The royal gift”) for it was dedicated to the royal patron Amīn Shāh Muḥammad b. al-Ṣadr al-Sa'īd Tāj al-Dīn Mu'izz b. Ṭāhir (1285). See Brockelmann Carl , Geschichte der arabischen Literatur (Leiden, 1938), supplement 11, 296.

This sentence appears in chap. 2 of Book II of Ṭūsī's Tadhkira. The whole second book is devoted to the configuration (hay'a) of the celestial bodies (ajrām), and the second chapter of that book is devoted to the arrangement of the celestial bodies and their order with respect to one another (Fī tartīb al-ajrām wanaḍādiha) (Leiden, Arabic MS, 905, folios 8r et seq.). The phrase itself occurs on folio 8v, lines 7–9.

Shīrāzī, fa'altu, Arabic MS, Majlis-i Shūrā-i Millī, 3944, folio 26v, lines 5–9.

See, for example, the statement of the problem of the motion of the ninth sphere in the Planetary hypotheses (ref. 12), 38, 42, et passim.

In the English introduction to the text of Mu'ayyad al-Dīn al-'Urḍī (d. 1266), The astronomical work of Mu'ayyad al-Dīn al-'Urdi: A thirteenth century reform of Ptolemaic astronomy (Beirut, 1990), 35, which was written during the academic year 1982–83, I had noted a frequent practice among medieval astronomers in that they re-wrote their own works. Although I knew at the time of two other astronomers doing so, I only speculated that Tūsī may have followed their example. My judgement was then based on the type of variants that were reported in the partial edition of Tūsī's Tadhkira, which was filed by Jamil Ragep as a dissertation at Harvard University in 1982, and I did not have the direct evidence implied by the statement quoted here of Tüsī's own student. See Ragep F. J. , “Cosmography in the ‘Tadhkira’ of Naṣīr al-Din al-Ṭūsī” (dissertation, Harvard University, 1982; University Microfilms International, Ann Arbor, no. 8222696). With this added evidence from Ṭūsī's own student, the practice of re-writing one's work can now be confirmed for Ṭūsī as well. More recently, Ragep has also reached the same conclusion (see his Naṣīr al-Dīn al-Ṭūsī's Memoir on astronomy (New York, 1993), 70–71).

Muḥammad b. Abī Ya'qüb Isḥāq al-Nadīm, Kitāb al-Fihrist (hereafter Fihrisi), ed. by Tajaddud R. (Teheran, 1971), 330–1.

Sezgin Fuat , Geschichte des arabischen Schriftums (Leiden, 1967–), vi, 147.

Régis Morelon has already edited this text of Qusṭā, and is preparing it for the press.

Sezgin , op. cit. (ref. 22), vi, 181–2.

Jamāl al-Dīn Abū al-Ḥasan al-Qifṭī, Ta'rīkh al-Ḥukamā', ed. by Lippert Julius (Leipzig, 1903), 262–3.

Almagest I, 8.

An account of this discovery is given in Almagest VII, 2, 3.

On the ninth sphere, see the Planetary hypotheses (ref. 12), 38, 42, etc.

See Planetary hypotheses (ref. 12), 38.

It should be remembered that modern library officials are not much more intelligent than their medieval counterparts. The reader need only be reminded of the cataloguer of the American University of Beirut Library who, during the 1960s, listed T. S. Elliot's book, Waste land, under agriculture.

This practice was obviously carried over into the Latin tradition as can be seen by such designations as “Liber trium fratrum”, or “Verba filiorum Moysi filii Sekir…” See, for example, Clagett M. , Archimedes in the Middle Ages (Madison, 1964), 223 et passim.

Qifṭī, op. cit. (ref. 25), 441–3.

Qifṭī, op. cit. (ref. 25), 315–16.

See Planetary hypotheses (ref. 12), 38, and Almagest, Toomer's translation (ref. 12), 35–36.

Shīrāzī, fa'altu, folio 34v.

For a study of the Arabic translations of the Almagest, see Kunitzsch Paul , Der Almagest: Die Syntaxis Mathematica des Claudius Ptolemäus in arabisch-lateinischer Überlieferung (Wiesbaden, 1974), 1–82.

Since the Arabic translation of the Almagest is not yet fully edited, and exists only in manuscript form, the text copied here is based on two surviving manuscripts of this translation, namely, Tunis, Bibliothèque Nationale, Ms. 07116, dated 478 A.H. (= 1085), folios lv-2r, and Paris, Bibliothèque Nationale, Ms. Arabe 2482, folio 2r. The variations between the two manuscripts are only scribal and pertain to omissions inserted on the margin. The Ḥajjāj translation of the Almagest has the following: “Wa-qad yumkin an yu'qala waḥdahu bi-ghayr al-ākhar. Wa-man ṭalaha an ya'lama mā al-sabab al-awwal al-ladhī li-l-ḥarakat al-ūlā, fa-sa-yathbutu lahu idhā basaṭa dhālika 'alā al-marātib annahu ilāh lā yurā wa-lā yataḥarrak, wa-anna ṣinfa al-nażar al-ladhī yubḥathu bi-hi 'an ṭalab al-'ilm bi-hi [sic] a'lā ‘ulūw al-’ālam yusammā ilāhīy^an wa-dhālika ma'aūl^un annahu mufāriq^un li-l-jawāhir al-ḥissīya.” (“It is possible to conceive of one without the other. And whoever seeks to know the first cause, which pertains to the first motion, it will be confirmed for him, once he details that in successive stages, it is a deity who neither is seen nor does he move, and that the kind of study in which one seeks to know it in the farthest reaches of the universe is called theological, and that is conceived to be different from the sensible substances”) (British Museum Add. 7474, folios lr-lv). In Toomer's translation of the Almagest (ref. 12), directly from the Greek sources, Ptolemy is supposed to have said: “None of these [three, i.e. matter, form and motion] can be observed in its substratum by itself, without the others: They can only be imagined. Now the first cause of the first motion of the universe, if one considers it simply, can be thought of as an invisible and motionless deity; the division [of theoretical philosophy] concerned with investigating this [can be called] ‘theology’, since this kind of activity, somewhere up in the highest reaches of the universe, can only be imagined, and is completely separated from perceptible reality” (pp. 35–36).

In Toomer's translation of the Almagest (ref. 12), we read: “Furthermore it can work in the domains of the other [two divisions of theoretical philosophy] no less than they do. For this is the best science to help theology along its way, since it is the only one which can make a good guess at [the nature of] that activity which is unmoved….” In the translation of Ḥajjāj this sentence is rendered thus: “Wa-ammā fī dark al-qismayn al-ākharayn fa-laysa 'awnuhu fīhimā bi-dūnⁱⁿ. Ammā fī al-jins al-ilāhīy fa-huwa al-muṭarqu [sic] al-sā'iqu ilayhi li-annahu waḥdahu faqaṭ min jins mā lā yataghayyar wa-ḥazruhu bi-lā 'amal taqrībⁱⁿ al-a'rāḍa al-latī fī-l-adwār wa-marātib al-ḥarkāt al-lawātī li-l-jawāhir al-ḥissīya al-muḥarrikāt wa-l-mutaḥarrikāt al-abadīya al-latī laysa fī-hā khilāf^un “(B.M. Add. 7474, fol. 2r). The text is obviously corrupt, but may be taken to mean: “As for the comprehension of the other two divisions (of theoretical philosophy) its assistance is not trivial. As for the metaphysical (science), it is the one that leads and conducts to it, for it alone is of the type that does not change, and guesses without any approximation the conditions that are at various cycles and orders of the motions that pertain to the sensible substances which move and are moved by the eternal that has no variation.”

Kunitsch Paul , Der Sternkatalog des Almagest: Die arabisch-mittelalterliche Tradition, i (Wiesbaden, 1986), 3, but more credibly, see the biography of Ibn Bulbul by D. Sourdel, in Encyclopedia of Islam, 2nd edn, s.v. “Ismā'īl”.

See, for example, Kunitzsch Paul , Ibn al-Ṣalāḥ: Zur Kritik der Koordinatenüberlieferung im Sternkatalog des Almagest (Abhandlungen der Akademie der Wissenschaften in Göttingen, Phil.-Hist. Klasse, 3. Folge, Nr. 94; Göttingen, 1975), 155.

This possibility was suggested to me by my friend and colleague Roshdi Rashed.

See Saliba , The astronomical work of Mu'ayyad al-Dīn al-'Urḍī (ref. 20), 43–49.

Brockelmann cites, for example, one manuscript in Turkey, AS 2668, but does not cite the two manuscripts used for this edition. See Brockelmann C. , Geschichte der arabischen Literatur, ii (Berlin, 1902), 212. Max Krause lists yet another manuscript in Turkey, namely, Fātiḥ 3175, 2°, 164v–240v. See Krause , “Stambuler Handschriften” (ref. 14).

I will translate falak with the term ‘orb’ here, in order to use the term ‘sphere’ for the word kura. The distinction is only formal for the two Arabic words are often used interchangeably.

The term used here is Arabic ḥorraka = to move (something) and not taḥarraka = to be moved.

Here the author uses the term kura = sphere.