Islamic Science and the Making of the European Renaissance

7. Age of Decline: The Fecundity of Astronomical Thought

The previous chapter demonstrated very clearly the kind of results that were produced in the Islamic world and the impact those results had had on Renaissance Europe. In the chapters before that, where I talked about the encounter with the Greek scientific legacy and the innovations that encounter produced, I also noted that although the critiques of Greek thought began early on, the more mature criticism and the confidence with which the Greek scientific edifice began to be dismantled and replaced by more consistent alternatives, and far more sophisticated deployment of mathematics, did not really take place until the later centuries of the Islamic civilization, and mostly after the thirteenth century. Thus, based on what we have seen so far, one is justified in saying that those later centuries of Islamic civilization seem to have been centuries of great creativity, at least as far as the discipline of astronomy was concerned. In addition, one could also say that, that creativity was not apparently restricted to revamping all of the Greek astronomical theory but it seems to have had a seminal impact on Renaissance science as well.

But these are precisely the centuries that the classical narrative had earmarked as representing the total death of science, not to say the total death of rationality in Islam, which is more often used in connection with this period. Without paying any attention to the kind of evidence we have been reviewing, which was mainly produced during the latter centuries of Islamic civilization, or even indicating that such evidence existed, the classical narrative formulated its theory of decline by basing itself on two main assumptions. Those assumptions were held by two different groups of people. And although each group had its own analysis of the intellectual history of Islam, they converged, almost independently, on considering the the age of decline to have begun in the thirteenth century.

For those who looked, from the very beginning, at Islamic civilization as a continuous unfolding of religious thought only, and at the same time held the European paradigm of the conflict between religion and science, they attributed this death of rationality in the Islamic civilization, and in this later period, to an upsurge in religious thought, which they claim came about at the expense of scientific and philosophical thought. For those people, "progress" was defined by the very victory of science over the church, just as European progress was defined. Thus every civilization had to demonstrate that it had participated in this struggle before it could participate in this "universal" linear and constant search for "progress." Those civilizations had to have their science overcome their church, even if one had to redefine "church" in the particular terms of the said civilization. In the case of Islamic civilization, the struggle of the Mu'tazilites against the people of tradition (ḥadīth) exemplified, to a great extent, the conflict paradigm between "science" and "religion", without ever bothering to define the "science" of the Mu'tazilites, or the "church" of the people of ḥadīth. In that regard Ghazālī's (d. 1111) book The Incoherence of the Philosophers (tahāfut al-falāsifah) constituted a real milestone. Not only because this group of people saw in it the direct connection between philosophy and science in that period, and hence an attack on one is an attack on the other, but because they also rightly considered Ghazālī as the initiator of an Islamic Orthodoxy of sorts, and thus his book symbolized the triumph of religious thought. The conclusion that is usually drawn from the success of Ghazālī's religious thought is that this triumph must have caused the death of its counterpart, the rational scientific thought. Thus in a simple fashion, Ghazālī was single-handedly held responsible for the decline of rational, read scientific, thought in Islamic civilization in these later centuries.[367]

Thus, pinning the cause of the decline of Islamic science either on the conflict paradigm between religion and science, a paradigm that was first and foremost imported from the European example, or on the fatal blow that was single-handedly delivered by Ghazālī against the philosophers, has become so widespread[368] that those approaches continue to have their deleterious effects on the very reading of the scientific texts that were written both before and after the Ghazālī period.

Focusing on the conflict between science and religion before the Ghazālī period may have contributed to the lack of awareness that there were scientists working during that period and whose main concern was to combat the imported Greek scientific tradition, because of the errors and blemishes it harbored, and not because of the religious thought of their time. Muḥammad b. Mūsā's critique of Ptolemy, or Rāzī's shukūk against Galen, or even Ibn al-Haitham's Doubts against Ptolemy, among many others discussed above, have gained some importance only recently as texts rebelling against the Greek scientific tradition, rather than texts rebelling against the religious authorities of their time. None of those texts made any significant impact on the group of people who saw Islamic history as an unfolding of religious thought, and in that sense those text were badly read if they were read at all. It is not accidental that both of Rāzī's book as well as that of Ibn al-Haitham's were edited in the latter part of the twentieth century, and not during the nineteenth century when most Islamic religious and juridical works were studied with great care by famous European orientalists.

But those same nineteenth-century orientalists summarily dismissed the scientific texts that were written after the Ghazālī period. And until very recently no one had ever bothered to investigate the kind of science they contained. In this sense those texts too were very poorly read if they were read at all. As an example of this misreading of texts, we have already seen the efforts of the two famous nineteenth-century orientalists who looked at two works from the post-Ghazālī period, and who read them very carefully, and still could not see the originality that was embedded in them, simply because those orientalists were not looking for any originality during this period.[369] And their self-fulfilling prophecies indeed materialized.[370]

The second group which saw Islamic history more in political terms, and thus portrayed it as a succession of dynasties and battles, with little attention paid to intellectual history, the bête noire that was made responsible for the decline of science in the Islamic civilization was after all Hulagu Khan.[371] Hulagu's devastating blow came at a time when he actually managed to destroy the city of Baghdad, in 1258, in his westward bid from Central Asia to conquer the rest of the world. Those who blamed Hulagu for the death of Islamic science took literally the anecdotes preserved in the historical sources, which were incidentally mainly written further west, in Mamluk areas that were not conquered by the invading Mongols. Those historical sources spoke of the water of the Tigris turning black from the dissolving ink of the manuscripts that were tossed into the river by that barbarian invader. They presented a scene of destruction that continues to stand in the collective memory of most Arabs, and Muslims in general, as the ultimate of disaster and the epitome of barbarity.[372]

In a sense, the dates of the death of Ghazālī (1111) and the devastation of Baghdad (1258) seem to allow for the conversion of the two historiographic traditions just mentioned, one of which saw Islamic intellectual history as an unfolding of religious thought and one of which saw it simply as a sequence of political events. No wonder then that most people could easily conclude that those two fateful centuries, the eleventh and the thirteenth, indeed ushered in the decline of Islamic civilization and with it the decline of science in general. This conclusion was especially true for people who also remarked that they no longer saw during those later centuries the emergence of religious legal schools that were anywhere similar to the four schools that had already emerged during the eighth and the ninth centuries, and was also true for people who no longer saw a continuity of the Islamic caliphate after the fall of Baghdad.

In that sense, the thirteenth century was in fact a fateful century, as it witnessed the final disappearance of a system of caliphate that had up till then functioned tolerably well. But as far as intellectual history is concerned, the extant scientific sources do suggest a different scenario. They suggest that the thirteenth century was an age where new creative scientific thought continued to prosper, and more importantly, they even support the claim that the disappearance of the caliphal system of government was almost a blessing in disguise. For the loss of that system did not seem to have brought the end of the scientific activity. On the contrary it seems to have opened up other centers of production in the lesser capitals, such as Diyār Bakr, Iṣfahān, Damascus, and Cairo, to name only a few, that continued to produce excellent scientific works.

In summary, and as has already been stated, none of those narratives of the age of decline can really explain the greater number of sources that seem to signal a real upsurge of scientific production both well after the death of Ghazālī and well after the Mongol devastation of Baghdad. And if one focuses on the discipline of astronomy in particular, as we have been doing up till now, the problem of pinning down the cause of the decline according to one of those two narratives becomes even much harder to solve.

In a separate book devoted to the study of one aspect of Arabic astronomy: the aspect of planetary theories, I went so far as to call that same age of decline the golden age of Islamic astronomy. In that book I traced the developments in Arabic planetary theories between the eleventh and the fifteenth centuries and demonstrated the fecundity of that discipline. That book, and the various articles that have appeared since then, dealing mainly with the work of the sixteenth-century astronomer Shams al-Dīn al-Khafrī, described an unparalleled originality during that period that would be difficult if not impossible to dismiss.

If one takes either explanation of the age of decline, as offered by either group of the proponents of the classical narrative, one is then faced with problems that will not easily disappear. In the first case, and for those who hold Ghazālī responsible for the age of decline, they will have to explain the production of tens of scientists, almost in every discipline, who continued to produce scientific texts that were in many ways superior to the texts that were produced before the time of Ghazālī. In the case of astronomy, one cannot even compare the sophistication of the post- Ghazālī texts with the pre-Ghazālī ones, for the former were in fact far superior both in theoretical mathematical sophistication, as was demonstrated by Khafrī, as well as in blending observational astronomy with theoretical astronomy, as was exhibited by Ibn al-Shāṭir. Similar original production can be easily documented as well in mechanical engineering, in medicine, and in optics, to say nothing of the whole class of astronomers who were all working after the thirteenth century, and whose purpose was to push the frontiers of planetary theories into the realm of alternative astronomy or "New Astronomy" as was proposed by Ibn al-Shāṭir.

To take only few examples, compare the works of 'Izz al-Dīn al-Jazarī (c. 1206),[373] who worked nearly 100 years after the death of Ghazālī, with those of Banū Mūsā in the ninth century.[374] Earlier in the ninth century period, Banū Mūsā focused on developing new devices and new techniques that were not known from the Greek tradition. For instance, we note the development of the conic valve in the works of Banū Mūsā, which is nowhere documented in the earlier Greek sources. We also note a shift from the Greek tradition that relied mainly on nature's abhorrence of void to animate the machines that they designed, to a more instrumental approach by Banū Mūsā where they used concepts of sources of power as running water, or flowing sand, to achieve similar animations. For Philo of Byzantium[375] or Hero of Alexandria,[376] for example, the siphon worked by water replacing the void, while for Banū Mūsā water flew and was interrupted by turning a conic valve on and off, by means of floats and other mechanisms that did not depend on the concept of void. It was in these later developments that they had to invent such tools as the conic valve and the like. This does not mean that Banū Mūsā did not understand the way void worked in nature and in the design of machines, but that they used it together with other techniques that they themselves developed.

Looking at the works of Banū Mūsā in comparison with the Greek tradition one cannot only detect a forward leap in the variation of techniques in their engineering designs, but can also detect their participation in the general cultural mood of early Islamic times that was critical of the Greek scientific tradition. However, when their works are compared to the work of Jazarī we note a remarkable maturity in the latter's work that is nowhere to be found in the works of Banū Mūsā. With Jazarī we begin to notice discussions regarding the real function of mechanical devices, and real appreciation of their significance as tools that did not only fulfill daily functions for the society, but that they were also tools that could demonstrate the way in which the natural physical principles worked.[377] His devices were examples of natural physical principles in action. And in the introduction to his book, he explicitly states that his devices were intended to actualize (ikhrāj min al-quwwa ilā al-f'l)[378] — the physical principles that were potentially there, waiting to be actualized. His full grasp of the Aristotelian approach to mechanical devices and their intrusion into the world of nature is far superior to Banū Mūsā's understanding of such principles as far as one can tell from their surviving writings.

Even the historical sources preserve for us anecdotes about the patrons of Banū Mūsā, especially al-Mutawakkil (ruled 847-861), and tell us that Banū Mūsā's devices had indeed enchanted him,[379] and that those skillful engineers produced for him such entertaining objects exactly to serve that very purpose. Contrast that with the patron of Jazarī who demanded of him, according to Jazarī's own introduction to his work, that Jazarī should compose the work in order to keep a record of the peerless "models" (ashkāl), things that he invented (istanbaṭa), and "illustrations" (mithālāt) that he brought forth. For anyone reading that introduction, the language reveals very clearly a fuller understanding of how mechanical devices operated and why they did. At times Jazarī would even explicitly state that he intended to illustrate the same principle with many devices, all in order to show the universal applications of those principles.

But as these texts have not been fully studied from those perspectives yet, one has to wait before passing any more detailed judgments about them regarding their relative merits. The impressions given here resulted from a first quick reading of the sources, and will, I am sure, finally withstand the test of analysis.

Or take the works of Ibn al-Nafīs in medicine. It was in his commentary on Avicenna's Canon that we find his remarkable remark that did not only depart from the teachings of Avicenna, whom he admired greatly, but went further to criticize Avicenna's original source, Galen himself. With his criticism, he ended up refuting the doctrines of Galen on the basis of his own observations, and thus laid the foundation for the eventual discovery of the pulmonary circulation of the blood.[380] It was in the post-Ghazālī period that such scientists seem to have gained a well-earned confidence in order to challenge their predecessors and through them attack the main Greek legacy that continued to be the site of contention, with such statements as "this is the common opinion, but according to us, it is false" (hādha huwa al-ra'y al-mashhūr, wa-huwa 'indana bāṭil). These are echoes of Ibn al-Haitham, 'Urḍī, Ṭūsī, and others who said, at one point or another, "This is the accepted opinion, but according to us it is false." In that regard, Ibn al-Nafīs reflects the same trend that was developing in astronomy, and had already had its roots in the works of al-Rāzī some four centuries before him. He also seemed to have been complementing the works of other scientists from other disciplines who were all engaged in a cultural revival rather than an age of decline.

Consider also the work of Kamāl al-Dīn al-Fārisī (d. 1320)[381] from the following century, which illustrates the same trend again, but from the field of optics. It was al-Fārisī's teacher, the great astronomer Quṭb al-Dīn al-Shīrāzī (d. 1311), who suggested to al-Fārisī that he study the work of the great scientist Ibn al-Haitham (d.c.1038) from the pre-Ghazālī period. Note that he was not advised to go as far back as the obsolete Greek optics for his study. Instead he was put to challenge the best and most recent production on the subject.

Neither the Greek tradition, nor Ibn al-Haitham had managed to explain the phenomenon of the rainbow properly, and thus up till al-Fārisī's time this problem had remained the site of competition and speculation. And it was al-Fārisī who finally put his mind to it, and developed the instrumentation in order to explain how the colors of the rainbow were in fact produced. And exactly like his predecessor, Ibn al-Nafīs, he too followed the same style, that is, he produced an elaborate commentary on the most advanced work of a pre-Ghazālī scientist. And in the context of that commentary he refuted the ideas of his predecessor and the ideas of the more ancient Greeks who had nevertheless been his models to some extent. In this regard, it should be remembered that although Ibn al-Haitham could be counted as a great scientist in his own right, he too did not hesitate to reject Greek ideas when they did not meet his exacting scientific standards. And yet it was al-Fārisī who had the final say in the matter of the rainbow.

In a sense,, this phenomenon is very similar to what took place in astronomy. Here too we find the formidable critique of Ptolemaic astronomy, which was leveled by Ibn al-Haitham in the middle of the eleventh century. We also find the same critique left as such, without anything more positive being done about it till the thirteenth century, when the astronomer Mu'ayyad al-Dīn al-'Urḍī (d. 1266), who lived more than a century after Ghazālī, complained against Ibn al-Haitham for not bringing anything new besides criticism. It was 'Urḍī who undertook the development of a whole alternative astronomy that was destined to replace the Greek astronomy, and thereby produced his famous mathematical theorem that made its impact on almost all astronomers that followed him. Here again there is no comparison between the brilliance of 'Urḍī and that of Ibn al-Haitham, startling and brilliant as Ibn al-Haitham was.

Still, in the discipline of astronomy this trend continued after 'Urḍī, through Ṭūsī, Quṭb al-Dīn al-Shīrāzī (d. 1311), Niẓām al-Dīn al-Nīsābūrī (d. 1328), Ibn al-Shāṭir (1375) and his contemporary Ṣadr al-Sharī'a al-Bukhārī (c. 1350), ''Alā al-Dīn al-Qushjī (d. 1474), Mullā Fatḥallāh al-Shirwānī (c. 1450), and finally to Shams al-Dīn al-Khafrī (d. 1550) to name only a few. Each and every one of those astronomers would take the works that were produced in the pre-Ghazālī period, and refer to them as the commonly known astronomy (al-mashhūr) only to attack them severely, and attack Ptolemy behind them as well. After having done that, they would then go on to build their own alternatives to that astronomy on grounds that were completely new, and on levels that were much more sophisticated than the levels found in the earlier period or the Greek sources themselves.

Like work in optics and medicine, the work of the astronomers was cast in the form of commentaries on each other's works, or at times on the Greek works themselves. They only used those commentaries as vehicles to produce their own alternative theories and to record their own scientific insight, much as was done by Jazarī, Ibn al-Nafīs, and al-Fārisī.

For people who had pre-judged this period as a period of decline in Islamic science, they saw in these commentaries a sign of decadence, without ever bothering to read them or appreciate the novel ideas that were contained therein. Even the most learned of the modern Arab intellectuals, once president of the Academy of the Arabic Language of Cairo, Professor Ibrahim Madkour, had this to say about this period, and the commentaries it produced: "Speculative thought was confined to increasingly narrow areas, scientific inquiry stagnated, and matters that had previously been studied and understood became obscure. Creative thinking and the spirit of discovery were replaced by sterile repetition and imitation, expressed in commentaries and studies of texts and stressing words rather than meaning."[382] How much more wrong could one be?

Professor Madkour, however, was not alone in that assessment. In fact, in the vast modern literature, one reads one such author after another all bemoaning the low state of Islamic science just because this period witnessed the production of commentaries instead of original works. Had these authors only read those commentaries, they would have realized that they could not have been much farther from the truth, for they would have also found one commentator after another saying: Ptolemy, or some other astronomer or Greek scientist, said this or that, but I say, and then insert their own novel ideas at the right context.

The problem with these kinds of judgments is that they clearly indicate that a true appreciation of the role of those commentaries has not been fully developed yet. In an earlier publication I had hinted to the fact that there is much to be found in those commentaries, and in that context gave only the example of the Ṭūsī Couple itself which I have demonstrated was first conceived in 1247, but in the context of a commentary on Ptolemy's Almagest.[383]Since then, and after reading many of the astronomical commentaries that followed Ṭūsī's, I have come to realize that those commentaries acted in a manner quite similar to our modern periodical literature. For when a modern author conceives of a bright novel idea, which was not conceived before, s/he would go ahead and compose an article that s/he would send to a specialized periodical announcing his/her own new idea. From then on, the new idea would enter the literature. And when enough of those ideas that deal with kindred subjects accumulate, they are then digested into a secondary book that popularizes them and finally allows them to enter the domain of public knowledge.

In regard to the popularization of new ideas, the medieval author has a greater advantage over the modern author, although his advantage has yet to be appreciated. For the medieval author, who had no access to specialized periodicals, as they did not exist at his/her time, the most efficient way of propagating his/her ideas would be to introduce them in the context of a commentary. For in such commentaries the new idea would in fact be properly contextualized and thus would gain a much greater significance than a lonely article in a journal that would need a lot of supplementary contextualizing information, not to say long years of waiting, before it could be fully appreciated, if at all. Needless to say, that on that ground alone, I now take the medium of commentaries to be a much healthier sign than even our own modern periodical scholarship.

Commentaries continued to be written throughout the post-Ghazālī period, and of course they continued to produce new ideas all the way till the sixteenth century, the last century, which has received a cursory study so far. This does not mean that they stopped then, for the later centuries have not even been investigated. Nor does it mean that there were no banal commentaries that were written during this period, for there were a lot, and many were indeed composed by mediocre minds that one finds in every age and place. But one can still document a series of commentaries, written by each and every one of the astronomers just mentioned, all building on each other's works, and all continuously taking up the challenge of perfecting the discipline of astronomy. By the sixteenth century, and with Shams al-Dīn al-Khafrī the commentaries reached such a sophistication that Khafrī could finally write two huge ones before he would eventually write an independent book, which he titled Ḥall mā lā yanḥall (Resolving that which could not be resolved). In the last, rather short text, he managed to produce a series of the most sophisticated solutions for all the problems that had plagued Greek astronomy and had become notoriously difficult to solve before his time.[384] In that instance, where most of the novel ideas were originally expressed in his commentaries before they were finally grouped together in his last independent original work, one can say that it was the commentaries that gave rise to originality rather than the other way around.

All this evidence points to one inescapable conclusion. Any one who takes the time to read the scientific production in the post-Ghazālī period would have to characterize this period as the most fecund, and in the field of astronomy in particular completely unparalleled. The disciplines that I have cited here, and the astronomers I have mentioned by name, all speak to a continuously ascending tradition all the way till the sixteenth century, being the last century that has been investigated although to a very modest degree.

As for those who still harbor the notion of the deadly struggle between science and religion, I only need to mention that with the exception of 'Urḍī, whose religious credentials are yet to be determined, every one of the other astronomers mentioned, as well as Ibn al-Nafīs himself, were all religious men in the first place. Not in the sense that they were religiously practicing men only, but that they also held official religious positions such as judges, time keepers, and free jurists who delivered their own juridical opinions. Some of them wrote extensively on religious subjects as well, and were more famous for their religious writings than their scientific ones. This evidence leads me to conclude that the model of conflict between science and religion, which may have worked in Europe somehow, and I am not sure it did for it sounds too simplistic to contain the truth, this model does not seem to apply at least as far as the Islamic civilization is concerned. Nor does it particularly seem to apply in the post-Ghazālī period, when we witness more of the men of science being men of religion. Nor did it ever seem to be analytically useful as far as the discipline of astronomy is concerned for most astronomical works seem to have been produced by men of religion, and most of them were in fact employed in religious institutions.

As for those who think of history as a series of political events only, and a sequence of dynasties and wars, without paying much attention to intellectual history, they too can take little solace by relying so heavily on the Mongol invasion in order to justify their theory of decline. For although it was true that Baghdad was indeed destroyed at the hands of Hulagu Khan, it so happened that his vizier at the time was Naṣīr al-Dīn al-Ṭūsī, the astronomer he had captured in the conquest of the Ismā'īlī fortress of Alamūt. It was this same Ṭūsī who had enough wisdom to save about 400,000 manuscripts before the sack of Baghdad. In addition, he even saved a young man by the name of Ibn al-Fuwaṭī, and took him along to what later became the Ilkhānid stronghold near Tabriz. There, on a hill at the edge of the nearby city of Marāgha, Ṭūsī convinced the son of the same destroyer of Baghdad to grant him enough support in order to establish one of the most elaborate observatories the Islamic world had ever known.[385]

Of course, it helped that the same Ilkhānids soon converted to Islam, and granted Ṭūsī what he asked for. And there, in the city of Marāgha Ṭūsī managed to assemble the most distinguished company of astronomers ever assembled in one place. The mere gathering together of such astronomers, at such an active center, equipped with a new library of manuscripts that were rescued from Baghdad and other Iraqi and Syrian towns, together with Ibn al-Fuwaṭī as a librarian, they collectively and individually managed to produce the most sophisticated astronomical theories of Islamic times. Some of them had already made their contribution before they came to Marāgha. Just as Ṭūsī himself had done when he proposed his new mathematical theorem, the Ṭūsī Couple, while he was still at Alamūt, as we have already seen. And as 'Urḍī too did when he had completed his most celebrated astronomical work, and his Lemma, when he was still in Damascus. But their getting together at Marāgha produced the kind of astronomy that Shīrāzī was able to popularize by starting a tradition of dialogue with earlier astronomers, via the cumulative work of commentaries, and when he wrote two very long ones of his own within twenty years from the building of the Marāgha observatory.

More importantly, one should also remember that the foundation of the Marāgha observatory was commenced in the year 1259, that is, exactly one year after the destruction of Baghdad. The engineer who constructed the instruments, and in all likelihood who also built the structures himself, as most of them were masonry structures that doubled as astronomical observational instruments, was none other the famous astronomer/engineer 'Urḍī himself. We are particularly fortunate to have a treatise written by this distinguished engineer, in which he detailed all the constructions that he accomplished at Marāgha, a treatise unequaled in its sophistication and utility, and the likes of which was unknown from the pre-Ghazālī period. Its importance can only be fully appreciated when we learn that it was also used as a guide for the construction of later observatories that were built in Samarqand during the time of Ulugh Beg (c. 1420) and in Jaypur, India, toward the end of the eighteenth century. The text of this treatise remains, unfortunately, unedited in a modern scientific edition, and is only partially translated.[386]

Both of the decline narratives, therefore, that attribute the death of science either to the success of Ghazālī's religious thought, or to the destruction of Baghdad by the Mongols, do not seem to explain the brilliant scientific production we just mentioned. Furthermore, and in light of what we already know, these two causes do not seem to have even slowed down the production of science and did not seem to have set an age of decline. On the contrary, one may argue that the period that followed was marked by an increase in scientific production, and a remarkable upgrading of its quality, so much so, to make the production in the pre-Ghazālī period look much more modest in comparison. And as I have already said, in the field of astronomy alone, I have already argued that the golden age of that discipline, in terms of the production of planetary theories at least, should in fact be located in the post-Ghazālī period.

But if that were the case, and if the age of decline could be so easily reconstructed as an age of fecundity, at least as far as astronomical production was concerned, then when was this age of decline, and what is one to understand by the term decline in the first place? 'Decline' is a relative term implying a comparison between two levels, one perceived to be lower than the other. And as we have just seen, when we compared the scientific writings produced in the post-Ghazālī period, in several scientific disciplines, and found them to be more sophisticated than the ones that were written before, and at times even written in direct opposition to those earlier writings, we were at all times comparing one scientific production against another, and many factors were taken into consideration in this process. On the basis of those comparisons one would have dared to say that the post Ghazālī period witnessed a renaissance in comparison to the pre-Ghazālī period, and thus the latter could in turn be described as an age of decline.

Some of those factors that went into the comparison had to do with the quantity of production, for it is quite natural to expect that a few texts here and there would not make a trend, and thus would not constitute a shift in the type and quality of scientific production. It is for that reason that special attention was paid to the number of scientists in the post-Ghazālī period whose works were considered in the comparison process. And here again, the case of astronomy did not only prove that there were far more scientists from the later period who produced more creative material, but that there were more of them producing material in opposition to the earlier astronomers. One can detect a clear trend of new ways of doing astronomy, and thus one will have to admit that the post-Ghazālī period deserves a special consideration.

Then the number of fields in which this production was compared had to be considered, for it would also be natural not to think of excellence in one field as a sign of a trend that should characterize a historical period as more or less advanced. And there again, the circle was widened to include such disciplines as medicine, optics, and mechanical engineering. In all instances one could find results that were more or less in agreement with what seemed to be happening in astronomy.

And if one were to take a look at the field of scientific instruments, one could also document a similar flourishing activity in this later period, not only in the remains of large scale observatories such as the ones that were built in Marāgha and Samarqand, but also include those that were built by Jai Singh II (1686-1734) in India in imitation of those earlier ones.[387] One can also notice, from the sheer number of scientific instruments, still kept at Museums all over the world, whether astrolabes, quadrants, sextants, or what have you, that the number of more and more refined instruments kept increasing in the later period. To take only one example, the development of the universal astrolabe, of which we still have several samples, is not only a masterpiece of workmanship, but is also theoretically superior to the astrolabes that were constructed in the earlier period. And so was the case with many other instruments.[388] Thanks to the abundant results that are now in print, one can simply assert that the field of astronomical instruments also witnessed a "golden age" in the post-Ghazālī period, in complete synchrony with the field of planetary theories, although the two fields are only poor cousins.

I know the number of disciplines that I have attempted to list here is by no means exhaustive, and here I must admit that lack of competence in the history of other disciplines restrains me from passing judgments about them in the same fashion. But I certainly welcome colleagues who work in those disciplines to double check the results that have been so obviously achieved so far and decide for themselves whether this period can still be called a period of decline. My suspicion is that we have surveyed a good representative cross section of disciplines. And most probably the results we have already achieved, and the assessments we are now making, will withstand such additional tests from other disciplines.

While it is true that most of those results point to an increased volume of brilliant astronomical production, all coming from the post-Ghazālī period, nevertheless none of those results seem to come from the relatively later period, namely, the period beyond the sixteenth century, as far as I know. Again for the field of astronomy, I dare say that this may be due to lack of expertise on my part, since I have not thoroughly investigated the later works. I have focused over the last two decades or so on the works that were produced between the thirteenth and sixteenth centuries, and have not paid enough attention to the mostly inaccessible works of the later centuries. Disciplines other than astronomy may have suffered from similar handicaps, and thus may one day turn out new material that is still undiscovered.

But a quick survey of the readily accessible astronomical texts produced after the sixteenth century revealed an interesting phenomenon. Not only do we begin to see a slightly different astronomical production, one more concerned with purely religious astronomy such as mīqāt, or simplified astronomical texts, but also as early as the seventeenth century we begin to notice an incursion of European scientific ideas coming back into the world of Islam. We can even find echoes of things happening in Europe during the sixteenth century beginning to be acknowledged in the Islamic world, and sometimes incorporated. Here I am thinking of one of the later Syro-Egyptian astronomers: Taqī al-Dīn ibn Ma'rūf (d. ca. 1586), whose work included, in his own hand, an acknowledgment of his direct acquaintance with the multi-lingual dictionary of Ambrosio Calepino (1435-1510).[389]

Later works in geography from the seventeenth century reflect knowledge of the various astronomical systems of Copernicus and Tycho Brahe, and also demonstrate how such works began to mention the discovery of the new world. All these echoes come in the context of the translations of such works as the Atlas Maior and Minor, into Turkish.[390]

In sum, I am willing to accept the fact that a thorough investigation of this later period, say from the sixteenth to the twentieth century, will definitely demonstrate an increasing dependence on the scientific results that were produced in European centers of learning. Production that was by then making its way back into the Islamic world. This process apparently continued unchecked during these later centuries until the Islamic world was finally brought to rely completely on European science during the colonial era of the nineteenth and the twentieth centuries. That dependence has even intensified further in the present time.

The latter part of the twentieth century demonstrates this complete dependence extremely well. For after all, this particular century witnessed the "independence" of most Islamic countries after having already undergone a long period of colonization that was brought to an "end" during that part of the century. And now, most, if not all Muslim countries, depend for all their scientific education on the scientific output of European countries, their colonial centers of yesterday, or say western in order to include the United States of America. This is also the case at almost all universities in the developing world, with the Islamic world planted in its midst. They all depend, in their scientific curricula, on what is produced in the west.

With the end of the twentieth century we can see the pendulum moving all the way to the west. And if we look at the source of science, we would then be in a position to witness the extreme end of the spectrum. But we should also ask: When did this shift take place? That is, when did Europe stop being interested in the scientific production of the Islamic world, and when did it begin to export scientific production to it?

Determining the time of that shift itself may help us determine the onset of the age of decline. But let me be clear on the concept of decline itself. In this context, I wish to define such an age as an age in which a civilization begins to be a consumer of scientific ideas rather than a producer of them.

Going back to the sources, as we have been doing all along, those sources seem to indicate a break that took place sometime around the sixteenth century, and that century seems to contain the seeds of that age of decline, or at least seems to have been the time when such decline may have commenced. And if my reading of those sources is valid, then we must look for the events that surrounded this particular century, i.e. the sixteenth century, in order to determine, if we can ever determine at all, the causes of that decline.

For a better diagnostic look at the age of decline, one must constantly bear in mind the relative nature of that concept, and must appreciate the fact that social processes such as cultural decline or Renaissance and the like are rarely datable to a specific decade or even a century. They usually are indistinguishable at first, but with the passage of time trends begin to consolidate and remarkable differences begin to be noticed. As was already noted by others like Needham, who will be referred to again below, if one were to compare the scientific production in the world of Islam, China and what is now Europe, just about the beginning of the sixteenth century, one would have noticed that all three were almost on equal levels. Two centuries later, say by the beginning of the eighteenth, that comparison begins to weigh more heavily in the direction of Europe.

Those 200 years, say roughly between 1500 and 1700, witnessed the creation of one scientific revolution after another in Europe and marked the definite birth of modern science. And for that same reason, they gave rise to the multiplicity of questions that have been asked ever since, all attempting to explain why did modern science rise in Europe and not in the other two competitive cultures of the time. Many have sought answers in the social make up of the cultures concerned, others looked at the legal, religious, and political conditions. Some have even taken the conditions of modern Muslim societies and projected them, in very essentialist and non- historical terms, back onto the histories of those societies.[391]

And yet the question has persisted for a long time now. And because of its sheer emotional and ideological underpinnings, in a world constantly polarized, it has not become any easier to answer. But if we focus on the big picture, that is a picture drawn over a period of a few centuries where the trends become clearer to observe, and if we widen the scope to the multiplicity of factors that may have caused the lopsidedness of the scientific production that becomes clearer to observe as well, then we stand a better chance at understanding not only the nature of the decline of scientific production in the world of Islam, but may also gain some insight into the social economic context of science itself. By applying the same methodology, which attempted to explain the rise of science in early Islamic times in terms of socio economic conditions, this time the same methodology may yet help us understand why within a period of two centuries or so there arose a remarkable difference between the sciences that were produced in Europe and those that were produced in the rest of the world, and most notably the Islamic world. From that perspective, it would no longer be interesting whether Copernicus knew of the works of his predecessors from the Islamic world or not. Instead the focus would shift to the conditions that led to the works of Copernicus to be incorporated into later, more advanced works, and systems of thought that led to the demise of the old Aristotelian world order. Most importantly, those developments indeed changed the very nature of scientific production itself. Therefore, those two crucial centuries have a lot to teach us about the nature of modern science, its relationship to the cycle of capital investment, and its relationship to the fluctuating political and economic conditions. It is under those conditions that one has to seek the meaning of the age of decline in the Islamic world that has noticeably set in from the sixteenth century on, without necessarily pinning that decline, if one can help it, to a particular cause, a particular event, or a particular train of thought, be it religious or otherwise. So what happened during those two centuries?

Political history of that period may after all be useful in this regard, and it does reveal some very interesting features. By the middle of the sixteenth century we witness, for the first time, a large-scale split of political power within the Islamic world. That split produced three great Muslim empires. They all came into existence around the same time, and with the exception of the Ottoman they all passed away around the middle of the eighteenth century.

With the Ottomans (c. 1453-1920), finally conquering Constantinople in 1453, they swept through the eastern Mediterranean in 1516, as far down as Egypt and large parts of North Africa, in order to consolidate their stronghold over that part of the Muslim world. The Safavids (1502-1736), farther east in what is modern-day Iran, came into power by the beginning of the sixteenth century, and with time established a new empire with Shī'ism as its official religion, thus perpetuating a rivalry with the Sunni Ottoman empire to the west and a friendlier but yet competitive relation with the Mughal empire to the south-east that lasted for centuries. The Mughals (c. 1520-mid eighteenth century) themselves, originally a Central Asian dynasty, spread southward to establish one of the long lasting empires in the Indian subcontinent.

Besides the disrupting effect of this internecine competition and warfare, other factors came into play, but all leading to a weakening of the cultural cohesion of the Islamic world. The religious sectarian competitiveness played an important role on its own, as it still does today. But then there was also the very important event that took place toward the end of the fifteenth century, and which shook the whole world order to its very foundations. The event in question was the discovery of the New World, which not only disrupted almost all of the well-established Euro-Asian trade routes that used to siphon commercial wealth into the Islamic lands for centuries, but it also brought new raw material into European countries just as those same materials were almost completely depleted in the Islamic lands. It is not accidental that all three Islamic empires came into being around the same time, during the early part of the sixteenth century, and disappeared around the same time, end of the nineteenth beginning of the twentieth centuries, as we just said. In order to understand this phenomenon better, we must examine it in terms of the socio-economical and political global shifts that were taking place around that time.

By the beginning of the sixteenth century, the so-called "discovery" of the New World had just begun, and the westward orientation of European exploration, trade, and access to untapped natural resources as well as to human slave labor, both in the New World and (later) in Africa, created a major conflagration all around the world. Only to be followed by the "Age of Discovery" in the next century, which witnessed a dogged search for more lands to "discover", more resources to acquire, and more colonies and slave labor to entrap. All of these events of the sixteenth and early seventeenth centuries re-oriented wealth and trade around the Islamic world, or say circumvented the Islamic world, and mostly to its disadvantage. And while almost every European royal house and its dependencies, in one way or another, began to receive tons of gold and silver, as well as free slave labor and other natural resources from the colonies, the Islamic world found itself then blocked to the west by the rising powers of the European royal houses. Those royal and princely houses were now wealthy and well equipped with commercial and maritime navies.

Circumnavigating around Africa by the Portuguese helped them spread their trade in the south-eastern direction at first, and eventually to the east where Portuguese and later Dutch colonies began to sprout as far down as southern India, up north the Indian Ocean till the southern edges of the Arabian peninsula itself, and farther east by the Dutch till the eastern edge of the known world. Eventually, that colonial exploration that reached the South Asian and the Chinese theater in the Far East began to re-route even the trade of that eastern region around the Muslim world rather than through it.

Yes, there were some windfall profits that came to the Islamic world as a result of trade with the newly discovered wealth of Europe. But on the whole, Islamic lands lost the commercial initiative they once had, and became more and more dependent on whatever wealth the European merchants were willing to part with while trading with ports in the Islamic world. In essence the relationship began to shift from producing wealth to consuming wealth in return for whatever natural resources were still available. And these are the whole marks of an age of decline. Yes, there were Venetian merchants who brought some wealth to Damascus, for example, by commissioning household products and items of high culture to be produced there, but that meant that the Damascene worker began, even then, to enter into a relationship of dependency where he was working for a foreign master. The dependence and consumerism that was set then and later began to characterize the relationship between the Islamic world and Europe continues till this day.

I do not know of a good study that elaborates on the effects of the "discovery" of the New World on the intellectual life of European royal and princely houses. But it is not difficult to detect, in several European areas, and toward the beginning of the seventeenth century, the appearance of new institutions that had no medieval parallels per se, and their very creation may have had something to do with this new acquired wealth. During the first half of the seventeenth century, Europe witnessed the rise of scientific and royal academies, a phenomenon that was not known before as such, at least not to that extent where almost every royal or princely house had an academy of its own. The purpose of those academies seems to have been directed at assembling the most educated men of the time and to liberate those men from the financial worries and the like. In their very structure, the academies offered those intellectual elites an environment of scientific and intellectual competition. And as we have seen before, it is the healthy competition that is usually conducive to the production of science. But most importantly, this whole movement came about at almost no cost to the patronizing royal houses, for the capital and the slave labor associated with the investment usually came through many circuitous routes from the "discovered" colonies. In regard to those scientific institutions, we only note that the first of them was the Academia de Lincei, which was founded in Rome in 1603, only to be followed by the Royal Society of England in 1662, and the Academie des sciences of France in 1666.

The connection between those academies and the "discoveries" in the New World is not always readily apparent. But one should note that the oldest of them, the Academia de Lincei, soon enjoyed the membership of none other than Galileo ca. 1609, whose work for the Venetian commercial navy is well known.[392] And one of the earliest projects of the Academia de Lincei was the re-publication of the survey of the medical plants of the new colonies in Mexico, which was then called New Spain.[393] That survey was completed few years earlier by Dr. Francisco Hernandez (1515-1587), at the request of King Philip II of Spain (1527-1598). Instead of verifying the older herbs of Dioscorides that were well known in the "old world" and were obviously commercially fully exploited by then, the academy, and of course the earlier royal patrons before it, began to look to the New World for new sources of wealth, and the medical plants were apparently such well suited targets.

It is only natural that in such institutions as the academies, where men of science were financed to further their research, and to think out new ideas, in an environment of competition with other academies and royal houses, as well as competition among the scientists themselves, new scientific discoveries would eventually be produced. The situation was not too different from the conditions we described in early ninth-century Baghdad, minus the institution of the academies that quickly became the norm in Europe. If one scientist in a hundred produced something in those academies that had a commercial windfall, then the wealth accumulated from the new idea would be returned to fund other ideas, and, of course, allowing the patron to keep some of the profits aside.

In this manner, I believe that the major scientific developments in Europe during the sixteenth and seventeenth centuries were the product of this dynamic cycle of wealth, mostly initiated by the "discovery" of the New World. Wealth drove further production of science, and in turn science allowed the acquisition of more wealth, and so on. This pattern seems to have been set then. And for those who look at the close relationship between modern corporations and the production of modern science, can easily discern the main features of this same dynamic cycle that is still going on.

At this sped-up rate, the production of science in what is now Europe began to grow almost at a logarithmic rate, leaving the rest of the world to struggle with its own depleted resources and its old ways of doing science. The Islamic, as well as the Chinese worlds, had up till that time a similar scientific status as that of Europe, as was so aptly noted by Needham more than 50 years ago.[394] But with the onset of the new dynamic cycle we just mentioned, that was set in motion by the end of the sixteenth and beginning of the seventeenth centuries, European science began to surge on, and both of the Chinese and Islamic worlds were left behind.

Returning to the age of decline in the Islamic civilization, in my opinion, this age of decline was less caused by such factors as a book of Ghazālī or the invasion of the Mongols, than by the external world circumstances of the sixteenth century and thereafter. And since the term decline implied a comparative context, as was stated above, in my opinion too, what seems to have happened was the onset of a race between the European royal houses and the rest of the world, including the Islamic world. And in that race, the Islamic world lost. But no one should forget that the real race started in the sixteenth century as a result of the discovery of the New World, and that it was a race between Europe, on the one hand, and the rest of the world, on the other. This race continues to intensify till this very day. In relative terms then, when one culture begins to produce more and better science, for now it can afford to, the other culture will look like it declined, no matter what.

Of course, the translation of the European superiority, and now add the United States' as well, in commercial, scientific and technological terms, into further acquisitions of resources and manpower from the rest of the world, and actual subjugation of the rest of the world to military occupation between the eighteenth and twentieth century, the so-called age of colonialism, which is still going on in many places, did not help in leveling the field of competition. So naturally, all non-western cultures look like they are experiencing an age of decline in comparison. And their decline too started around the year 1600, nearly 100 years after the discovery of the New World and during which European royal houses learned how to translate the benefits of that discovery into political power.

As far as I can tell, neither Islamic science, nor Chinese science, for example, had managed to start a capital-driven cycle through their methods of production. In the Islamic world the institutions of science, such as observatories, hospitals, and even the various houses of science (individually called dār al-'ilm) that were mainly patronized by wealthy individuals, and at times the ruling sultan himself, were never directed at acquisition of further wealth, and never attained a self sustaining economic status that would have guaranteed their survival and perpetuity. They could produce brilliant scientists, such as the ones whose works we have examined, ever so briefly, but they could not guarantee the continuous production of the scientists themselves through the security of their income and position. As a result, the scientific production of the Islamic world was mainly driven by individual genius but only when those geniuses could by accident encounter the right patron who would offer the support.

For modern times, the problem of catching up with western science is not only a problem for the Islamic world alone. Instead it has obviously become the problem of the whole so-called second and third worlds as well. And now they all seem to be locked in this competitive race for which the non-western world neither possesses the necessary capital, nor the infrastructure, nor the manpower to compete on fair grounds. Add to that the constant brain drain that continues to feed the first world at the expense of the second and third, a fact that makes this race even harder to win.