Or is it?

Before Ghazali came along, three intellectual movements [orthodoxy, philosophy, and Sufism] were competing for adherents in the Islamic world. After Ghazali, two of these currents had come to an accommodation and the third had been eliminated.
—Tamim Ansary¹

As I described in my previous post, the impact of Abu Hamid Ghazali (d. 1111) on the Muslim world was enormous. He’s been called the Proof of Islam and the greatest Muslim after Muhammad. His book The Incoherence of the Philosophers, in which he attacks nothing less than the cornerstone of Western civilization, reason, was hugely influential. Thanks to Ghazali, Muslims stopped writing books about philosophy and science and literally started burning them. The rationalist current in Muslim thought, which had once flourished and produced intellectual giants like Avicenna, Biruni, and Omar Khayyam had been, as Tamim Ansary and many others observed, eliminated.

That’s the standard narrative, anyway. But is it true?

It’s a question that numerous scholars have revisited in recent years, and a growing number of them answer no. The flaw in the narrative, they argue, is that no decline in the Muslim pursuit of science ever occurred, or if it did, it occurred so long after Ghazali that ascribing it to his influence strains credibility.

Among the skeptics is Nassim Nicholas Taleb, author of The Black Swan. “Many thinkers blame the Arabs’ later abandonment of scientific method on Alghazel’s huge influence,” he writes, “though apparently this took place a few centuries later.”² Jan P. Hogendijk and Abdelhamid Sambra insist that “The Islamic tradition in the exact sciences continued well into the nineteenth century, and abundant source material is available in the form of unpublished manuscripts in Arabic, Persian, and other languages all over the world.”³ Mohamad Abdalla, Founding Director of the Griffith University Islamic Research Institute, disputes whether this abandonment happened at all. In a 2007 paper, he calls the theory “a scholarly error that has proven to be remarkably persistent despite the availability of contrary evidence.”⁴ Citing Columbia’s George Saliba, Abdalla argues that the technological gap between Islam and the West, which was so readily apparent by the 18th century, was not so much a matter of a decline in Muslim science as “the result of the industrial leap forward that Europe achieved, particularly after the discovery of the Americas.”

The critics of the decline narrative point out—correctly—that there were still many brilliant and productive Muslim scientists long after Ghazali. Oft-cited examples include Nasir ad-Din Tusi (d. 1274) who served as astronomer and theoretician to the Assassin Cult. After their stronghold of Alamut was destroyed by the Mongols, he found employment with his new overlords and built the Maragheh Observatory in Azerbaijan. Ulugh Beg (d. 1449), despite being the grandson of Tamerlane, was a better astronomer and mathematician than a ruler—the ruins of his observatory may still be seen in Samarqand. The social scientist ibn Khaldun (d. 1406) is credited by Arthur Laffer with laying the foundations of supply side economics half millennium before Dr. Laffer himself proposed his eponymous curve.

In his magnum opus, the Muqaddimah, ibn Khaldun surveys the state of Muslim science during his time:

Scientific activity disappeared there [North Africa and Spain], save for a few remnants that may be found among scattered individuals and that are controlled by the orthodox religious scholars…5 This may be exemplified by our previous statements concerning Baghdad, Cordoba [Spain], al-Qayrawan [Tunisia], al-Basra and al-Kufa. At the beginning of Islam, the civilizations (population) were large, and sedentary culture existed in them. The sciences were then greatly cultivated there, and the people were widely versed in the various technical terminologies of scientific instruction, in the different kinds of sciences, and in posing problems and (inventing new) disciplines. They exceeded (all) who had come before them and surpassed (all) who came after. But when the civilization of those cities decreased and their inhabitants were dispersed, the picture was completely reversed. Science and scientific instruction no longer existed in those cities, but were transplanted to other Muslim cities. We, at this time, notice that science and scientific instructions exist in Cairo in Egypt, because the civilization of (Egypt) is greatly developed and its sedentary culture has been well established for thousands of years. Therefore, the crafts are firmly established there and exist in many varieties. One of them is scientific instruction.6

Professor Abdalla cites these passages as evidence that the decline paradigm is wrong; indeed they are the centerpiece of his paper. Scientific inquiry didn’t decline in the Muslim world, he argues, it merely moved around, “transplanted to other Muslim cities.” This was driven by population declines in some areas, and not merely because academic inquiry was “controlled by the orthodox religious scholars” influenced by Ghazali, albeit that was a factor.

IMHO, these are strawmen arguments. Despite the use of hyperbole, like Ansary's word "eliminated," no one who is familiar with the history of science in the Muslim world really believes or claims that scientific research stopped entirely after Ghazali. What they claim is that there was a lot less of it. Indeed, the fact that the same handful of post-Ghazali scientists keep coming up in these discussions, Nasir ad-Din Tusi in particular, suggests how few of them there were.

Ankara University’s Aydin Sayili captures the situation eloquently In his book The Observatory in Islam (which, incidentally, was indispensable to me in writing the scene in The Thread of Reason which takes place in Omar Khayyam’s observatory). In an appendix on “The Causes of the Decline of Scientific Work in Islam” he writes that after the 900s there was a

decrease in the energy and the vitality of and the general interest in scientific work…There was a gradual, if not uniform, decrease both in the intensity of production of first-rate work, and in the frequency of appearance of first-class scientists...Men of such calibers did not disappear during the later centuries, but they became increasingly rare.7

Indeed there is abundant evidence that Sayili is right. Certainly any list of the mega-minds of medieval Muslim science would be disproportionately clustered around the 9th and 10th centuries. Even during Ghazali’s lifetime, the decline of science had become evident, as his sometime friend, Omar Khayyam complained bitterly,

We have witnessed the decline of the men of science, now reduced to a thin troop, the number of which is as small as its afflictions are great, and to which the rigors of fortune have imposed the common obligation to devote themselves, as long as they last, to perfect and explore a single science. But most of those who in the present day appear to be scholars, deceive the truth with lies, do not go beyond the limits of sham and scholarly ostentation, and only use the quantity of knowledge, they only have material and vile goals.8

I already mentioned, in my previous installment, the frustration that ‘Abd’ul-Latif al-Baghdadi felt trying to find philosophers and scientists in Cairo when he visited in 1191, and the burning of science books that Rabbi Joseph b. Judah witnessed the following year in Baghdad. And the very ibn Khaldun passages that Prof. Abdalla’s cites to show that scientific inquiry continued to flourish three hundred years after Ghazali also say that it had been reduced to “a few remnants” in half the Muslim world and that in the other half it had disappeared from previously flourishing cultural centers like Baghdad, Basra, and Kufa. This is not a picture of a healthy scientific community; at best the passage only partially supports Prof. Abdalla’s case.

Admittedly, these arguments are somewhat soft, relying as they do on general impressions of the “energy” and “vitality” of the Muslim scientific community and anecdotal evidence from narrators who, as the postmodernists never tire of reminding us, have their own agendas.

However, there is one field of Muslim science where the level of activity has been quantified, and that is astronomy. In a 1956 paper, E.S. Kennedy, of the American University of Beirut, surveys every medieval Muslim astronomical table (in Arabic, zij) that is known to us—over a hundred in total—both those that are extant and those that are only known through mentions in other works. He then plots them based on when and where the observations were made, from the 8th to the 15th century, and from Afghanistan to Spain.

As you can see, as the centuries pass, not only are there fewer astronomical tables, but observations increasingly move away from the center of the Muslim world in Iran and Iraq, and move toward the fringes, places like Samarqand, home to the previously mentioned Ulugh Beg Observatory (#12 in the lower right corner of the chart. Omar Khayyam is #22 and Nasir ad-Din Tusi #6).⁹

Needless to say it is risky to draw conclusions about Muslim science as a whole by extrapolating from a single field of study. However, it should be noted that many of the Muslim rulers were superstitious and consulted their astrologers before any major decision. They therefore continued to provide state support for charting the stars and planets long after the Golden Age had passed. This was especially true of the Il-Khanid (Mongol) dynasty that patronized Nasir ad-Din Tusi—which accounts for the cluster of data points in Iran around the year 1300 in the Kennedy chart. It is therefore likely that the decline in other fields of scientific endeavor was far more severe than in astronomy. Relying on the astronomy data errs on the side of conservatism.

The zij data supports quantitatively what was already widely believed anecdotally: that there really was a decline in Muslim science. It also shows that, contrary to what Taleb and others claim, the decline began a hundred years or so before Ghazali lived, and not hundreds of years after. But that in itself is problematic, and raises serious questions as to the extent Ghazali was responsible for it. Questions which I’ll address in the final installment of this series.

Michael Isenberg drinks bourbon and writes novels. His latest book, The Thread of Reason, is a murder mystery that takes place in Baghdad in the year 1092, and tells the story of the conflict between science and shari’ah in medieval Islam. It is available on Amazon.com Please follow Mike on Facebook and Twitter. Subscribe to Islam: the Good, the Bad, and the Everyday Photo credit(s): CC by-SA 4.0 Igor Pinigin

¹Ansary, Tamim, Destiny Disrupted: A History of the World through Islamic Eyes, New York: Public Affairs (2009), p. 113. ²Taleb, Nassim Nicholas, The Black Swan: The Impact of the Highly Improbably, 2nd Ed., New York: Random House Trade Paperback (2019), p.83. ³Quoted in Abdalla, Mohamad, “Ibn Khaldun on the Fate of Islamic Science after the 11th Century,” Islam & Science, Vol. 5, No. 1 (Summer 2007), p. 66. ⁴Abdalla, op. cit., pp. 61-70. ⁵Ibn Khaldun, The Muqaddimah: An Introduction to History, Franz Rosenthal, tr., Vol. 3, p. 117, quoted in Abdalla, op. cit. ⁶Ibid, Vol. 2, p. 343. ⁷Sayili, Aydin, The Observatory in Islam and its place in the general history of the observatory, Ankara: Truk Tarih Kurumu Basimevi (1960), pp. 408-413 ⁸Khayyam, Omar, L’Algèbre d’Omar AlKhayyâmî, Paris: Benjamin Duprat (1886), F. Woepcke, tr., pp. 34-35. Translation from the French is mine. ⁹Kennedy, E.S., “A Survey of Islamic Astronomical Tables,” Transactions of the American Philosophical Society, 46:2 (1956), pp. 123-177.

Portents of Infection

Did Avicenna invent quarantine in the 11th century?

In the wake of the coronavirus crisis, numerous claims have been making the rounds of cyberspace to the effect that during the Middle Ages, Muslims had an almost modern understanding of infectious disease and the steps that should be taken to combat it. In particular, it is claimed that Islam implemented quarantine centuries before the practice became common in Europe during the Black Death.

In my previous installment, I discussed what Muslim scripture had to say on the subject of disease and quarantine, and how it was interpreted by the theologians of the time. The bottom line was that although there are passages about not entering or leaving areas where plague has broken out, they are more about patiently submitting to the Will of Allah, than about trying to divert His Will by taking steps to combat the disease.

But in addition to its theologians, the medieval Muslim world was known for its scientists. They were certainly ahead of the curve in many areas, including medicine, and in this installment I’m going to take a look at the state of the art of medical science, circa 1000 AD. I’m going to focus in particular on the king of all medieval Muslim physicians, Avicenna. Born in 980 in what’s now Uzbekistan, Avicenna was a Renaissance Man hundreds of years before the Renaissance, with accomplishments in mathematics, astronomy, chemistry, and poetry. He even served in government when a satisfied patient, the Emir of Hamadan, made him his vizier (prime minister).

But it’s for his medical works that Avicenna is best known. His Canon of Medicine was the textbook on the subject, both in the Muslim world and in Christendom, up until the 1600s. Some claim that he invented quarantine and even that he came up with the forty day isolation period, which later became common in Europe and gave the practice its name (quaranta is Italian for forty).

I thought it was suspicious that all the claims about Avicenna and quarantine came from secondary sources—no actual quotations—so I did some research and found no place in the Canon of Medicine or Avicenna’s other works where he recommends the practice. The earliest references I could find come from around 1500, when reformers like Ilyas bin Abram al-Yahudi, a Jewish convert to Islam, attempted to persuade a reluctant Ottoman Court to adopt state-of-the-art medical practices. In her excellent 2012 book, Plague, Quarantines and Geopolitics in the Ottoman Empire, Birsen Bulmus speculates that, “Perhaps Al-Yahudi sought to cover his own personal arguments – like his warning ‘not go in crowded districts’ – with earlier renowned authorities so that his recommendations would be accepted within literary Islamic traditions.”¹ In any case, al-Yahudi’s arguments fell on deaf ears—quarantine would not be established in the Ottoman Empire until 1838, and even then, only after considerable debate.

Indeed, it would have been strange for Avicenna to champion quarantine, given the understanding of health and disease that prevailed in his time. Despite the hype one hears about the great accomplishments of medieval Muslim physicians, it is, frankly, a mixed bag. They made great strides in diagnosing disease and assembling massive catalogs of symptoms. For example, A Treatise on Smallpox and Measles by Muhammad ibn Zakariyya ar-Razi (854-925), known in the west as Rhazes, is the oldest book we know of to distinguish between the two diseases (For an amusing story about Rhazes’s foray into psychology, see here). But when it came to understanding disease, and treating it, things were considerably more hit or miss.

The obstacle was that the germ theory of disease didn’t exist. The conceptual framework of medicine had not progressed since the time of the Ancient Greeks. The prevailing theory was Galen’s notion of the four humors—blood, phlegm, green bile, and black bile—and their corresponding properties of hot/cold and wet/dry. Under this theory, illness was the result of the humors getting out of balance, and the cure was to eat foods with opposite properties of temperature and moisture in order to compensate. Green bile, for instance, was thought to be hot and dry and therefore an excess of it caused fevers. Thus, to cure fever, the green bile needed to be balanced with something cool and moist. Although we do find some powerful drugs in the Muslim pharmacopeias—in a recent post about a tenth century cookbook, I included a recipe for opium-based cough drops—treatments were mostly food-based and bordered on quackery. In the case of fever, gourds and pomegranates were thought to be especially effective.

As for what causes the humors to fall out of balance in the first place, there were various theories.

Take smallpox, for example. Since Bubonic Plague was taking a rest—the aftershocks of the Plague of Justinian had died out around the end of the Umayyad Caliphate (750) and the Black Death of the 1300s was still centuries away—smallpox was probably the most dangerous disease with which the physicians of the Islamic Golden Age had experience.

Absolutely everyone got it, usually during childhood. Either they survived or they didn’t—the death rate was about 25%. If they survived, they never got it again.

Based on these observations, physicians concluded smallpox was just a normal part of growing up. Both Rhazes and Avicenna described it as a process of rot or fermentation in the blood. According to The Canon of Medicine,

Its symptomatic cause is the natural fermenting [or boiling] of the blood to shake out the remaining menstrual nourishment that was mixed in it from the time of pregnancy…like what nature does in squeezing the grape until it becomes a drink resembling its essence [i.e., wine].2

Still, this didn’t explain epidemics, why smallpox would break out in large numbers in certain times and places. Along those lines, Avicenna did have some rudimentary notion about contagion. One paragraph in The Canon of Medicine lists diseases that can be spread from person to person, and the manner in which they’re spread:

And among the diseases, some are contagious, like leprosy, scabies, smallpox, infectious fever, and festering wounds, especially where the houses are cramped, or likewise if the neighboring houses are downwind. Also conjunctivitis, especially from gazing into the eyes of someone else, and toothache from imagining biting into something acidic. Also pannus and leprosy.3

However, this was not so much due to the transmission of germs from person-to-person—Avicenna knew nothing of the variola virus—as it did with the presence of bad air, or miasmas, in certain places. Hence the significance of whether a house was closely confined or downwind from an infected house.

Sometimes the reason is that winds carry bad vapors from distant places that have stagnant water in them, or wounded bodies from battles, or those who died from fevers and weren’t buried or burned. And sometimes the reason is proximity to a neighboring place. And sometimes corruption is shown to be hidden in the ground for reasons not understood in detail. Then the water and the air are prepared and the fevers occur.4

Avicenna fills page after page describing how winds, seasons, temperature, humidity, and even the heavens affect the quality of the air. For example,

If we see the south wind increase, and days of turbid air, and then after that it becomes clear for a week, and then a cold night occurs that extends into a hot, hazy, cloudy day, then an epidemic might come that causes infectious fevers and smallpox and their like. And likewise if there was a cool summer and the atmosphere was heavy with soot. And comets, fires, and meteors in the fall are portents of infection as well.5

"As for improving the air," Avicenna writes,

...it is the goal to dry the air. Make the air good and prevent the rottenness from entering and crude matter from returning with ambergris, camphor, musk, and a measure of candy, storax, sandarac, asafetida, clove resin, mastic, terebinth resin, laudanum, honey, saffron, cypress, juniper, moss, bay leaf, sedge, 'adhkhar, savin, waja, shababk, bitter almonds, and so forth. And take these components in vinegar and asafetida and sprinkle the house...perfume with incense: sandalwood, camphor, pomegranate peel, myrtle, apples, quince, teak, tamarisk, and ribas. The perfuming must be repeated.6

This use of perfumes and incenses to fumigate the bad air was common practice. The historian as-Suyuti (d. 1505) tells of an incident during the "Plague of the Notables" (716-717), when a merchant appeared before the prince Ayyub, son of the Caliph Suleiman. The desperate courtiers grabbed the merchant's supply of musk right out of his hands. It didn't work though. When the merchant returned a week and a half later, Ayyub and all his household were dead and the palace boarded up.⁷

Clearly these three theories—maturation of the blood, person-to-person transmission, and miasmas—are not entirely consistent with each other, despite all appearing in the same book, and sometimes on the same page. The miasma theory is the one to which Avicenna dedicates the most space, and also the one which one hears the most about in the works of other authors. It is, of course, entirely at odds with the idea of quarantine.

If disease is the product of a foul and pestilent congregation of vapors that have accumulated in some place, then rather than hunkering down where you are, the logical thing to do is escape to some more wholesome locale. The chronicles of the Umayyad period are rife with accounts of rulers fleeing their palaces during outbreaks of Bubonic Plague. Finding higher ground was especially popular, since it was believed that the miasmas had an affinity for hollows and valleys. In the example I gave in my previous post, in which the Caliph Omar relocated his troops during the Plague of Amwas, their destination was the higher elevations of Hauran, in what's now southern Syria.⁸

Despite the vaunted reputation of medieval Muslim physicians in general, and Avicenna in particular, there is not only no evidence that they invented quarantine, but the idea wouldn't even make sense to them, given their basic ideas about medicine. Some of which were downright laughable. Obviously comets have nothing to do with smallpox, and even though conjunctivitis is highly contagious, spreading it requires some form of contact; you don’t get it merely by gazing into the eyes of someone who has it.

Still, we shouldn’t laugh too hard. Their painstaking classification of disease and symptoms laid the foundation for what was to come. The pioneers of modern medicine stood on the shoulders of giants, and Rhazes and Avicenna were giants indeed.

Michael Isenberg drinks bourbon and writes novels. His latest book, The Thread of Reason, is a murder mystery that takes place in Baghdad in the year 1092, and tells the story of the conflict between science and shari’ah in medieval Islam. It is available on Amazon.com Please follow Mike on Facebook and Twitter. Subscribe to Islam: the Good, the Bad, and the Everyday Photo credit(s): Ether Monument, Boston Public Gardens from Wikimedia Commons

¹Bulmus, Birsen, Plague, Quarantines and Geopolitics in the Ottoman Empire, Edinburgh: Edinburgh University Press (2012), p. 44.
²Avicenna, Qanun fi al-Tibb (Canon of Medicine), Book IV, Beirut: Muʻassasat ʻIzz al-Dīn (1987), Chapter 3, Section 67. All translations from The Canon of Medicine are mine.
³Avicenna, Qanun fi al-Tibb (Canon of Medicine), Book I, Beirut: Dar al-Kotob al-Ilmiyah (1999), Chapter 2, Section 8.
⁴Avicenna, Book IV, op. cit., Chapter 3, Section 65.
⁵Ibid, Chapter 3, Section 66.
⁶Ibid.
⁷See Michael W. Dols seminal article, "Plague in Early Islamic History," Journal of the American Oriental Society, Vol. 94, No. 3 (Jul. - Sep., 1974), p.379.
⁸Dols, op. cit., pp. 376-380.