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21.09.41 Juste et al. (eds.), Ptolemy’s Science of the Stars in the Middle Ages

21.09.41 Juste et al. (eds.), Ptolemy’s Science of the Stars in the Middle Ages


This is a marvellous book, with only minor reservations. It is one product of a twenty-five-year (sic) project, now nearing its halfway mark, that exudes scholarship, but not in a dry way. It is a quite remarkable mixture of chapters by established scholars and newcomers. It is not just about Ptolemy and his influence; it is also about the development of science, particularly the movement from the domination of philosophical ideas to the importance of empirical observations.

Ptolemy’s Almagest and his later Geography were incredibly influential. The Almagest was the pre-eminent book on astronomy in Europe and the Middle East for over a thousand years and his Geography was still in vogue when the Iberians started exploring the Far East. The influence of these books, and other writings by or ascribed to Ptolemy, was not only in Mediaeval Western Europe but, and just as importantly, throughout the Middle East. Owen Gingerich famously characterized Copernicus’s De revolutionibus orbium coelestium (which essentially updated theAlmagest) as “the book nobody read”; such cannot be said of Ptolemy’s works.

The range of the present book may look daunting, but the remedy is to explore the parts that entice. There is philology, history, comparative literature, mathematics and, of course, indeed Ptolemy’s principal interest, astronomy/astrology. (In the first millennium and a half of the common era, the astronomy/astrology distinction was at times non-existent, at other times emerging as important.) Readers should pick and choose, and this review will only lightly touch on each chapter.

The book begins with a beautifully written introduction. Then Alexander Jones takes on the fraught question of what exactly Ptolemy wrote, and when, in a clear and magisterial fashion.

The bulk of the papers concern interpretations of editions or translations but the volume starts and ends with a chapter on the mathematical front. First, Sidoli analyses Ptolemy’s methods in his Analemma with great insight. Instead of just presenting the work, he sets out the basic procedures in a very simple way. Foremost is the idea of projecting the three-dimensional world on to two dimensions. But he also shows how Ptolemy used practice to illuminate theory. Thus he describes Ptolemy’s use of a model, albeit with imperfections, to represent the cosmos (see also Hullmeine’s contribution). Then he goes on to correlate the practical use of a compass and straightedge (plus chord table trigonometry) to work out the requisite angles (see especially 71-2).

Despite its long pre-eminence, authors, especially in the Middle East, made attempts to improve the Almagest. Hullmeine considers modifications of the basis of Ptolemy’s theory: the eight spheres on which the heavenly bodies -- the sun, moon, five visible planets and the fixed stars -- sit. While Aristotle argued for a large number of spheres, al-Fārābī and Avicenna proposed just one more than the eight. As was quite usual at the time, the philosophical aspects had a considerable impact, not just the empirical observations. Some writers ascribed nine spheres to Ptolemy, though there are only eight in the Almagest, and the subject was discussed more in the Middle East, by both Jews and Muslims, than in Western Europe (81-2). The Ptolemaic ascription derives from the Planetary Hypotheses, which survives in its entirety only in Arabic and Hebrew. Hullmeine also raises the question of whether Neoplatonist philosophy influenced the Arab tradition. The whole discussion is based on a close reading of Greek and Arabic texts. He finally shows, using the work of al-Bīrūnī, that the imputation of a ninth sphere was due to John Philoponus (sixth century CE) who “altered the way in which medieval astronomers and philosophers thought about the Ptolemaic cosmos” (93).

Dimitrov’s contribution “demonstrates the relevance of the Semitic translations for the overall transmission history of the [Tetrabiblos]” (98). His scholarly philology not only establishes connections and yields clarifications, but also sheds light on how the translators between the different languages worked: in most of the cases he considers this means producing a close, literal, virtually word-for-word version, just as Gerard of Cremona would do with the Arabic Almagest three or so centuries later. The exception is the Syriac manuscript Dimitrov is currently editing, which seems to steer a course between literal and paraphrastic (111).

Thomann tantalizingly introduces a small fragment of an anonymous Arabic translation of the Almagest from the time of al-Ma’mūn. Interestingly, it uses astronomical terminology found in al-Khwārizmī (125). It is one more step in teasing out the history of the Almagest.

Grupe’s main conclusion is that Thābit ibn Qurra’s version of the Almagest was more popular than had been supposed. He achieves this by looking at several manuscripts in Arabic but also at a translation of the Almagest from Arabic into Latin in Dresden, SLUB, Db. 87, fols 1r-71r. However, he says: “A direct reception of Thābit’s text is difficult to determine” (154). The chapter is also tantalizing because only partial information about the Jaipur manuscript (Maharaja Sawai Man Singh II Museum Library, 20) is disclosed, though the author does give forward references to his later work on that.

In sharp contrast, with clarity and modesty, Langermann argues for a more nuanced view of Arabic commentaries on the Almagest. His own previous work looked at how commentaries challenged Ptolemy’s views, whereas now he sees a variety of approaches, principal among them the ideas of explicating matters not dealt with sufficiently in the original (159). He considers the commentaries of Ibn al-Haytam, Jābir ibn Aflaḥ and al-Bīrūnī. The last is not a straight commentator; he reviews “each one of the six cosmological principles that are established in Book I of the Almagest” (173). One particularly useful contribution is to encourage the study of other commentaries in order to understand how the Almagest was understood and, yes, criticized, in “a wide spectrum of cultures and varying historical contexts” (179). Indeed, this is a major aim of the whole book and enterprise, particularly linking the Middle Eastern readings to Western European ones.

Jābir ibn Aflaḥ’s commentary al-Kitāb fī l-Hay’a, or rather four Arabic versions of it, is the subject of Bellver’s contribution. It had wide influence, being translated by Gerard of Cremona into Latin as well as circulating as far east as Iran (186-7).

Astrologers interpreting charts of the heavens at a person’s birth traded on the names of Ptolemy and Hermes Trismegistus in the way they made their calculations. Casulleras analyses these and shows that some methods were indeed attributable to Ptolemy, while noting that “competent astronomers” complained about the attribution of natal astrologer’s methods to Ptolemy (219), but connections with the much more mysterious figure of Hermes are highly problematic (211).

Glosses, their purposes and utility are titillatingly introduced in Zepeda’s chapter. While he concentrates on Paris, BnF, lat. 7256, he delineates their uses and gives some hint of how and why they have been added to the manuscript. Although he provides many details, diligent readers will have to wait for Stefan George’s catalogue of glosses on all manuscripts of Gerard of Cremona’s translation for comprehensive coverage of even a circumscribed variety of such glosses on Ptolemy.

Henry Bate (1246-c. 1310) was an extremely well-connected astronomer/astrologer knowing, for example, William of Moerbeke. Steel provides a fascinating commentary on Bate’s prologue to his translation of Ibn Ezra’s Book of the World, as well as providing a transcription and English translation (268-79). Bate’s work is particularly valuable since he is very cognisant of the problems of accurate measurements with scientific instruments and yet moves to prioritise physical observation over the philosophical (and theological) metaphysical theories that had such a huge influence over early “scientific” thought. Throughout his chapter Steel is not only precise and analytical (correcting some earlier misreadings) but very sensitive to the whims of human scientists. He presents an absorbing picture of scientists at work.

Readers unfamiliar with the Pseudo-Ptolemaic Centiloquium, or καρπός, which comprises a hundred aphorisms, should start by reading Boudet’s conclusion (299-300), where they will find a good, though short, account of the significance and influence of three specific aphorisms (5, 8 and 51) on Catholic dogma. Boudet singles out half a dozen of the Latin versions of each of these for close consideration. (Boudet refers to Mavroudi’s paper that is not included here, see 283. It is scheduled to be published as a book, currently titled The Byzantine Reception of the Karpos attributed to Ptolemy and the Origin of the Text, in the same series as this volume.)

Shank’s (very long) chapter on disputes between Regiomontanus and George of Trebizond reminds me of Jacques Lacan’s seminar on the purloined letter (http://www.lacan.com/purloined.htm). There is a problem that the Epitome of Regiomontanus was not widely circulated, though he had intended it to be (308). So Shank is (re?)constructing the thought of Regiomontanus without the benefit of extensive comments from his contemporaries (310). Happily. Shank concentrates on Almagest 9.1 (starting on 311). The influence of the Planetary Hypotheses through Campanus of Novara on George is slowly adduced, although George did not know the original source (314 and 336). After detailing George’s views, Shank turns to those of Regiomontanus (347). As Shank notes, “George almost certainly never saw” the criticisms of Regiomontanus, though he may have heard of them (380). The putative debate would have to wait for Copernicus who provided a different resolution.

Rutkin looks closely at Pico della Mirandola’s sustained attack on astrology in his Disputationes adversus astrologiam divinatricem of 1496, which Rutkin is currently translating into English. The attack used any means available, even turning Ptolemy’s work against him when it suited, though using Ptolemy positively at other times (390-1 and 400). Pico’s work is vast and Rutkin, in this chapter, concentrates on religion. He gives us a tantalizing glimpse into Pico while sparing us (at least for the time being) from full details of the 376 mentions Pico makes of Ptolemy in the Disputationes. The chapter allows Pico to speak for himself, using Rutkin’s English translations with the original Latin in footnotes.

The last paper is again mathematical. Like Hullmeine, Kremer notes the shift to paying greater attention to empirical observations (particularly by Eichstad in 1622, 408). The work of Longomontanus is the focus of Kremer’s attention but, since Longomontanus wrote at great length, the focus is on Mars. In the ensuing explication Kremer manages to weave together consideration of interactions between Longomontanus and others with a close mathematical analysis of how Longomontanus engaged in his “bricolage.” “He was the last astronomer to create a theory in the Ptolemaic tradition” (440).

The quality of the contributions is uneven, though usually extremely high. The differences seem to stem from, on the one hand, neophyte zeal, where the author assumes the reader knows the same background, and the accumulated experience displayed by other writers, who contextualize their work for a more general reader. For example, the contrast between Grupe’s minutiae and Langermann’s graciousness is palpable.

One thing this book lacks is a good index--the three provided do not cover subjects. However the book is available through Open Access on BrepolsOnline, so searching is not a problem.

Finally, the actual production of the book is excellent, both physically and in terms of copy editing; obviously great care has been taken at every stage. Would that all, or even simply more, books were produced to such high standards. To parody, indeed invert the title of an old British TV comedy series about tailoring: “Never mind the breadth, feel the quality.”