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Background Supplementary Notes

Chronology of Political Events in Islamic History

Various notes on Arabic science

1. Islamic religion was central to Islamic civilization, and therefore it played a central role in shaping the transmission into and the appropriation of science in the culture. For example, the translation of scientific works on such a massive scale could not have occurred without huge financial support; it was a patronized activity fully supported by Islamic rulers and elites, much as occurred later in the similar effort to translate Arabic and Syriac sources into Latin for western Europe. Lindberg does an excellent job exploring some of the reasons why Islamic intellectuals supported this vast endeavor. Such things do not happen by accident!
    
2. Here is a sample of some of the Arabic-language scientists you will encounter in later chapters of Lindberg:
• Al-Khayyami (Omar Khayyam): mathematics, algebra, treatise on cubic equations, Rubaiyat, worked at Samarqand, Isfahan.
• Ibn Rushd (Averroes), 12th century, Cordoba, Spain. Known as "The Commentator" because his comprehensive commentaries on the Aristotelian corpus became a standard reference in the Latin west.
• Ibn Sina (Avicenna), 980?-1037; wrote the Canon, perhaps the most important Arabic treatise on medicine, and an important work on geology.
• Al-Battani (Albatenius), d. 929; astronomy, wrote the Sabian astronomical tables.
   
  
3. Historians tend to speak of "Islamic science" as well as "Arabic science," because the civilization was predominately Islamic in orientation but not ethnically Arabic. There were many different ethnicities and varied religious persuasions, including Jews, Christians (e.g., Hunayn ibn Ishaq), pagans and Sabeans (e.g., Thabit Ibn Qurra). For example, Christian communities in the Middle East (including what is now Iraq) continued to exist up through the late 20th century. Because of the varied religious persuasions of scientists writing in Arabic, their works can be referred to as Arabic language science. Because the culture was predominately Islamic, it can also be called Islamic science. On the other hand, neither "Arabic" nor "Islamic" science are perfectly apt:
   "one still has to find a name for the production of the Tusi Couple, that was first encountered in an Arabic text, written by a man who spoke Persian at home, and used that theorem, like many other astronomers who followed him and were all working in the "Arabic/Islamic" world, in order to reform classical Greek astronomy, and then have his theorem in turn be translated into Byzantine Greek towards the beginning of the fourteenth century, only to be used later by Copernicus and others in Latin texts of Renaissance Europe.  What name could one possibly dream up for that kind of science, and whose science was it anyway?"
   George Saliba, "Whose Science is Arabic Science in Medieval Europe?
    
   
4. Although the civilization was not essentially Arabic in an ethnic sense, it was Arabic in a linguistic sense. Arabic became the language of scientific expression across an immense geographical span.
    
• Geographical span: As a leading historian of Islamic science, A.I. Sabra, explains: “It was through the vehicle of Arabic that a non-Arab scholar in eleventh-century Nishapur or fifteenth-century Samarqand had access to the results arrived at in ninth or tenth century Baghdad, and an astronomer working in fourteenth-century Damascus became acquainted with writings produced in eleventh-century Cairo, twelfth-century Spain, or thirteenth-century Maragha.” Sabra continues: “With the decline of Abbasid power and the eventual breakup of the Abbasid empire centers of learning multiplied across the Islamic world following the proliferation of dynastic rules that vied with one another for cultural and intellectual eminence as well as for political power.”
   
• Arabic language: Sabra explains: “The result of these [early translation] efforts over a period of roughly one hundred and fifty years was that the Arabic language came to acquire a scientific legacy never before equaled in richness and variety.... never before had there been so many translations from so many sources into one language.” Just think of all of the examples of Arabic scientific vocabulary we use today! A few examples from mathematics and astronomy include: Algebra, algorithm, zenith, azimuth, nadir, Almagest, Deneb, Altair and countless other star names.
   
• Once translated, works in Arabic became widely available thanks to the geographical span of Islamic culture and the increasing availability of books. The secret of making paper was obtained from Chinese prisoners of war in the 8th century. Since paper was much cheaper than papyrus or parchment; manuscripts could be made available at relatively affordable costs; e.g., sell a donkey instead of about 30 sheep. By the 11th century, a technical work like Ptolemy's Almagest could be expected to lie within the reach of determined scholars.
   
  
5. What were the institutions in which Islamic science was pursued? Lindberg notes the absence of universities as in the Latin West, and points out that the madrasa curriculum did not require the study of science, yet more needs to be said...
    
   
1. Madrasas were schools of religious law, and although their significance for science may be unclear in some respects, even the teaching of religious law required non-trivial competence in mathematics and astronomy. For example, muslim leaders had to be able to calculate the rules of inheritance in order to implement Islamic justice, and these rules were quite mathematical. Second, any muslim leader needed to be able to calculate the qibla, which is the direction to Mecca, because five times each day muslims are instructed to pray facing Mecca. From your location, can you calculate the precise direction on this spherical Earth to face toward any distant city? The qibla required rather sophisticated competence in spherical geometry. Many astronomers earned their keep as the muwaqqit, or timekeeper of the local mosque, to calculate the qibla, maintain the religious calendar, and to determine the proper times of prayer. This example shows something of the kind of assimilation Sabra emphasizes in articulating the "appropriation thesis" as Lindberg mentions. For reasons like these, the marginality thesis is now quite marginal among historians of Islamic science today, and the appropriation thesis has overwhelming support, despite agreement that Islamic science had a precarious institutional base (as in Greek and Roman culture), and therefore was pursued with the private support of rulers and the personal dedication of scholars.
    
   
2. Observatories are a specifically scientific institution that illustrates the role of ruler patronage. Motivated by belief in astrology, many rulers maintained observatories, which entailed the construction of a building, maintaining a staff of technically trained astronomers, amassing a library and collecting appropriate instruments. Because patronage was critical to the existence of the observatory, however, few survived intact when rulers changed, particularly if the incoming ruler did not share his predecessor's belief in the importance of astrology. Astronomers would then become itinerant scholars forced to travel in search of patrons in neighboring regions.
    
   • Example #1: One of the most important astronomical observatories was founded in 1259 by Hulagu, a Mongol ruler, in Maragha (in Azerbaijan, now northwestern Iran). The Maragha school, as it is known, enjoyed an exceptionally long life of 57 years. Despite its short longevity (in comparison with contemporaneous medieval universities), Maragha hosted some very surprising advancements in Ptolemaic astronomy. The Persian astronomer Nasir ad-Din al-Tusi (1201-1274) worked on problems raised by Ptolemy's Planetary Hypotheses, which as Lindberg explains was concerned with describing possible physical structures of the universe that would correspond with the geometrical models of the Almagest (more on this below). In short, Nasir al-Tusi developed a geometrical device called the "Tusi couple" that acts like a crank mechanism, sliding a planet directly toward or away from the center of the deferent. The Tusi couple resolved a problem with Ptolemy's lunar models, which accurately predicted the position of the Moon but required the Moon to appear with a greatly varying diameter (which is not observed). Therefore the Tusi couple could move the Moon farther out or closer in as needed to maintain a more constant apparent diameter of the Moon.
     PS: As we will see, in the 16th century Copernicus knew of the Maragha school because he used a Tusi couple in his lunar theory, directly appropriating this technique from Islamic astronomers. [See Jamil F. Ragep, "Tusi and Copernicus," Science in Context, 2001, 14:145-163.]
     Note: many lunar topographical features are named after Islamic astronomers.
      
   • Example #2: Another justly famous observatory located in Samarqand (modern Uzbeckistan), was founded in the 15th century by Ulugh Beg (d. 1444), who was the grandson of the conqueror Tamerlane. At Samarqand huge instruments were constructed, far larger than the more widely known instruments of Tycho Brahe at Uraniborg a century later. As governor of Transoxiana and Turkestan, Ulugh Beg not only supported the mathematical sciences, but also became proficient in them.
     • Ali Qushji, an astronomer at the Samarqand observatory until his arrival in Constantinople after the death of Ulugh Beg, was one of the major figures of 15th-century astronomy. For example, Copernican scholar Noel Swerdlow has shown that Copernicus founded his heliocentric (Sun-centered) system upon two unusual propositions he found in Book XII of Regiomontanus' edition of Ptolemy's Almagest (1496). These propositions were denied by Ptolemy, but historian Jamil Ragep has shown that they were affirmed and demonstrated by Qushji around 1430. Swerdlow concludes: "In this way Regiomontanus provided the foundation of Copernicus's great discovery. It is even possible that, had Regiomontanus not written his detailed description of the eccentric model [in these two propositions], Copernicus would never have developed the heliocentric theory... While I do not believe that Regiomontanus ever advocated the heliocentric theory, he was, through these two propositions, virtually handing it to any taker." Through the more recent work of Ragep, we can now say the same of Qushji. Moreover, in a commentary on a theological work by al-Tusi, Qushji argued that astronomy should dispense with Aristotelian physics. Setting physics aside, therefore, Qushji concluded, since neither observation nor mathematics proves the contrary, the rotation of the Earth must remain a possibility. [See Noel Swerdlow, "The Derivation and First Draft of Copernicus's Planetary Theory, Proceedings of the American Philosophical Society, 1973, 117: 423-512; and Jamil Ragep, "Ali Qushji and Regiomontanus," Journal for the History of Astronomy, 2005, 36: 359-371.]
        
       
6. An example of the vitality and originality of Islamic science is the Islamic critique of Ptolemy's Almagest. In the spirit of Ptolemy's Planetary Hypotheses (described by Lindberg), Ibn al Haytham in the early 11th century founded a tradition of Islamic astronomical investigation that sought to reconcile Ptolemaic geometrical models with plausible physical mechanisms. The problem at its most basic consists of this: In a rotating sphere, the axis of rotation runs through the center of the sphere. Yet Ptolemy’s equant requires a sphere to rotate uniformly around a point not on its axis, which is mechanically impossible for a rigid sphere. Review Lindberg's definition of an equant model; do you see why this is the case? If not, here is an extended explanation:
    
• First, review these animated models of various geometrical devices to ensure that you understand them: | Equant system for outer planet on epicycle; Earth eccentric; with Sun | Craig Sean McConnell (scroll down to equant animation) | Ptolemy's models for outer planets, Peter Barker & Andres Idrobro | Nicholas Gross | Dennis Duke, click on Ptolemy's Moon |
   
• We can't take a styrofoam ball and model its rotation around an equant. A sphere is defined by a point and a given radius that sweeps out a circumference in 3 dimensions. A rotating sphere has an additional entity, an axis, that passes through the center. If one changes any of those three entities (center, radius, axis of uniform rotation) one no longer has the same sphere. Yet the equant model does precisely this: it calls for a sphere to rotate uniformly around a point not on its axis (the equant). One might as well try to shift the center to the equant, shorten or lengthen the radius on the fly, and smoosh the circumference as the sphere continues to rotate. The only way to do it is to make the sphere elastic or fluid, like a nerf ball; otherwise it’s mechanically impossible for a rigid physical sphere to move this way. And if it does move this way, by definition it's not really a sphere anymore, because the center, radius, and axis are not constant. Noel Swerdlow and Otto Neugebauer, Mathematical Astronomy in Copernicus’s De Revolutionibus (Springer-Verlag, 2 vols) explain this in a summary point about Ptolemy's astronomy (p. 41): Ptolemy’s “Planetary Hypotheses contain physical representations of the models that are supposed to exist in the heavens and produce the apparent motions of the planets, but these lead to difficulties, the most notable being the violation of uniform circular motion by spheres that are required to rotate uniformly with respect to points not located on their axes, and thus rotate nonuniformly about their axes.”
   
• Further on (pp. 43-44), Swerdlow and Neugebauer summarize the Arabic critique of the equant: “...when Ptolemy's planetary model is physically represented as complete spheres, a problem arises in that the sphere carrying the epicycle must rotate uniformly around a point, the equant point, not on its axis, so that the motion of the sphere with respect to its axis is nonuniform. The serious physical, or mechanical, problem is that there is no way of compelling a sphere, a ‘simple body’ in the Aristotelian sense, to do this all by itself.”
   
• ***In the 13th century at the Observatory of Maragha in northwest Iran, the astronomers Nasir al-Din al-Tusi (1201-1274) and Qutb ad-Din ash-Shirazi (1236-1311) developed non-equant models, as did Ibn ash-Shatir (1305-1375) the following century in Damascus. These astronomers criticized Ptolemy for geometrical devices like the equant that could not be represented by physical models.***
   
7. Appropriation thesis: To refer to Arabic-language scientists as merely the “curators of the Museum of Greek science," as Duhem could say at the turn of the 20th century, is no longer possible among informed historians of science (in this sense there was no "Dark Ages"). Over the last half-century, the appropriation thesis described by Lindberg (and first articulated by Sabra) has been overwhelmingly supported by historical research. Most of Lindberg's examples of Islamic contributions to, and transformations of, various fields of science are noted in later chapters of the text, but at the start it might help to list just a few Islamic scientific accomplishments...
• extended number theory to include irrational magnitudes
• developed trigonometry (synthesizing the Greek chord with the Indian sine and tangent)
• created algebra
• solved higher than quadratic equations
• probed the foundations of geometry, particularly Euclid's parallel postulate
• contributed greatly to the theory and practice of optics: burning mirrors, rainbow, etc.
• further developed the ideas of John Philoponos on what became known as impetus theory, an alternative to Aristotle's theory of natural motion that anticipated 17th century concepts of inertia.
• constructed sophisticated astronomical instruments: sundials, armillary spheres, astrolabes, quadrants, and equatoria (see note on Ulugh Beg's observatory, above).
   
  
8. Lindberg raises the problem of the decline of Islamic science. To me, the most interesting point is that today no one argues any longer that Islamic culture had science, and this new realization that Islamic science was so dynamic and impressive is what makes the problem of its demise seem to require explanation. So now historians debate a thousand suppositions to explain the decline of science in Islam, including the following major kinds of arguments:
    
   1. Institutional isolation: Were Islamic scientists were supported by a precarious institutional base, in contrast to Babylonian scribes and medieval Latin universities?
       
   2. Intellectual isolation: Might Islamic science have been handicapped by its tenuous ties to philosophy? By seeing science as natural philosophy, Europeans worked through the implications of natural knowledge in an explicit, systematic and integrated manner.
       
   3. Loss of peace, prosperity, and patronage: Just as with the decline of the Roman empire in the west, the support and pursuit of science requires social stability. Might political upheaval, factional warfare, and external threats from Christendom and Mongols on either side suffice to explain the decline of science in Islam?
       
   4. Decline is NOT the problem: Why does decline require explanation after all? The above explanations of decline fail to appreciate the precariousness of natural philosophy in the first place, under even the best conditions. Science doesn't keep going of its own inertia; every example of its occurrence, not its absence, requires explanation. Even in the US today, science could perish in an organized form in one generation unless general and specific cultural conditions are maintained. Therefore, what should surprise us, and occupy our full explanatory powers, is not the decline but the emergence and development of science in Islamic culture.
       
   5. What decline? Is it far too premature to talk about an alleged decline of Islamic science, because too many manuscripts still await initial examination? Perhaps Arabic science remained vigorous up into the 18th century! There were still meaningful exchanges between European and Ottoman scientists up through the generation of Newton. Learn Arabic, become a historian of Islamic science, and you can spend the rest of your life exploring scientific texts that no one else alive today has yet seen! All we can do today is affirm our ignorance of the later course of Islamic science, because too few scholars have yet studied it (see the remarkable example of Qushji, described above).
       
      • Which of these explanations, or which combination of these explanations, seems more plausible to you?
    

	HSCI 3013. History of Science to 17th century Kerry Magruder, Instructor, 2004-14 Brent Purkaple, TA Report typos or broken links	Go to this course at Janux spellcheck.net | wordcounter.net Many thanks to the pedagogical model developed in Mythology and Folklore and other online courses by Laura Gibbs, which have been an inspiration for this course.	Academic Calendar
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