Science and Islam_A History_Icon Science

by Ehsan Masood

  However, with technology, it’s not always so easy to see how a new invention or discovery came to be. Without physical evidence we cannot be sure whether an invention was entirely the work of the inventor, or the extent to which he may – or may not – have borrowed from his peers. This is partly because many of the ‘missing links’ in terms of working objects from the past are simply not available.

  These are some of the reasons why it’s hard to be sure of the precise extent to which Islamic technology was picked up in Western Europe, and the extent to which modern technological developments came about independently of things that happened in the past. From the examples of al-Jazari and the Banu Musa brothers, it seems that technology in Islamic times was notably advanced. We find references to crankshafts, which would become a key component in the machines of the European Industrial Revolution. We find cam-operated valves, which came into their own in the internal combustion engine. And there are references to automatic valves and double-action pumps, as well as technology directed towards raising water – and also using water to provide power.

  Many technologies helped to power the Industrial Revolution, and from what we have seen in this chapter, the scientists and engineers of the Islamic world could well have played a part.

  Part III

  Second Thoughts

  13

  An Endless Frontier

  Whosoever seeks the truth will not proceed by studying the writings of his predecessors and by simply accepting his own good opinion of them. Whosoever studies works of science must, if he wants to find the truth, transform himself into a critic of everything he reads. He must examine tests and explanations with the greatest precision and question them from all angles and aspects.

  Hassan ibn al-Haitham, Cairo, 11th century

  Much of this book has been concerned with how scientists from Islamic times contributed to the modern world. We have looked at both scientific and industrial processes. The previous chapter looked at engineering, and before that we had mathematics (algebra and trigonometry) and medicine. And in astronomy, for example, Arabic-speaking astronomers were found to have made a contribution to the work of Copernicus. Islamic scientists, however, had an impact in other fields which may well have helped shape the world as we know it today, including optics and the development of universities. Moreover, there is good evidence of early thinking in the Islamic world on the topic of human origins.

  Seeing is believing

  The nature of vision, and finding out the mechanisms for sight, are among the oldest questions in the history of human knowledge. These were of interest to scientists from the Islamic world too, and by the time of the translation movement from Greek to Arabic, scholars such as ibn-Sina and ibn al-Haitham were well aware of the leading theories in optics of the time.

  Perhaps the most popular of these theories of vision was what is now called the extramission theory, whose proponents included Plato. According to extramission theory, the human eye is able to see objects because the eye releases a special kind of optical energy. This energy can be regarded as being a bit like electromagnetic radiation; it streams ahead out of the eye in pulses, shining a sort of light, which allows humans to see.

  The extramission theory wasn’t without its critics, however, and they included Aristotle. The critics believed that, instead of a light pulsing out of the eye, our vision is more likely to come from a light that is released from physical objects themselves, which then interacts with the eye. This theory is known as intromission, and is not far off from our latest knowledge of vision.

  Galen, the pioneer of herbal medicine, had yet another view: he shared the extramission idea that the eye emits optical energy, but he also held that our ability to see happens when this energy mixes with the surrounding air and with sunlight.

  Among the first scientists of the Islamic world to get to grips with theories of vision was Abu Yusuf al-Kindi, the Kufa governor’s son who became scientific advisor to three caliphs, starting with al-Mamun. Al-Kindi, like his patron, acknowledged the Greeks as the original masters but, like many of his contemporaries, he also knew that advances in learning would require improving and refining ideas from the past:

  It is fitting for us to remain faithful to the principle which we have followed in all our works, which is first to record in complete quotations all that the ancients have said on the subject. Second, to complete what the ancients have not fully expressed, and this according to the usage of our Arabic language, the customs of our age and our own ability.

  (From Theories of Vision: From Al Kindi to Kepler by David Lindberg, Chicago, 1976)

  Other proponents of extramission from the Islamic world included al-Farabi (who died in 950) and the astronomer Nasir al-Din al-Tusi.

  Extramission was also supported by a second group of scientists, led by the medical doctor and translator from Baghdad, Hunayn ibn-Ishaq. Hunayn and members of his camp were largely on Galen’s side of the argument, however. They believed that, yes, the eye emits an optical energy, but that our ability to see is achieved when the energy from extramission mixes with air and sunlight.

  Criticising the rival intromission theory, Hunayn asked his readers to imagine that a large group of people – say 10,000 – are all standing before a tall mountain. If this mountain were capable of emitting images of itself, Hunayn said, then it would need to know that it has to send out 10,000 sets of images so that every person standing before it can see the mountain. As it is impossible, he argued, for mountains to know how many people will be looking at them, this meant that intromission had to be false.

  Hunayn’s ideas were extremely influential, both in the Islamic world and beyond, according to historian David Lindberg. Hunayn’s book Ten Treatises on the Eye ‘influenced almost every member of the Western optical and ophthalmological tradition before the 17th century’.

  A different view

  Intromission, though less popular among Islamic scientists, did have influential supporters. Among these was al-Razi (who died in 924). Using his experience as a working physician, al-Razi discovered that the pupil of an eye contracts and dilates depending on how much external light it receives. This was in stark contrast to Hunayn’s view that the pupil dilates according to the pressure of the visual energy that the eye is about to release.

  In addition to al-Razi, some of the most powerful and convincing attacks on extramission were made by ibn-Sina. In spite of being Galenist in his medical writings, ibn-Sina parted company with his mentor on extramission. Extramission was contrary to common sense for ibn-Sina; he could not believe that something as small as an eye could produce the energy necessary to be capable of travelling great distances, such as to the stars in the sky, and that this process would need to happen every time the eye opened. Moreover, said ibn-Sina, if it were true that vision occurs when energy from the eye mixes with air and sunlight, then stars and distant planets should be invisible to the naked eye, because air does not touch these distant objects.

  Ibn-Sina’s critiques of extramission were powerful and to a certain extent convincing. However, he was unable to significantly advance our understanding of vision. Instead, the job of taking the study of optics to new heights fell to ibn al-Haitham.

  Optics goes to new heights

  As we have already encountered, ibn al-Haitham lived in the 10th century and worked for the Ismaili caliphate (the Fatimids) based in Cairo, under the ruler al-Hakim. He worked in a range of fields, though he is known in the West chiefly for his works on optics and astronomy, including The Book of Optics, On the Spherical Burning Mirror, On the Light of the Moon, and Doubts Concerning Ptolemy. Ibn al-Haitham was a skilled experimentalist and he used his abilities to great effect when testing out the theories of the day.

  He began his criticism of extramission by describing what happens when people are exposed to bright lights. For example, anyone who tries to look directly at the sun experiences pain, he said, as do those who try to look at the sun’s reflection in a mirror. No mat
ter what the light source, the effect of bright lights, according to ibn al-Haitham, was always – and painfully – the same. This suggested to him that light entering into the eye from an external source had at least some role to play in vision.

  Furthermore, he argued, even if we did accept that the eye released a visual energy which interacts with the air (Galen’s view), the result of this interaction would need to flow back into the eye so that vision could be registered by the observer’s brain. This confirmed to him that, even if we accept extramission, some form of intromission would be needed for the eye to be able to see.

  To test his ideas out further, he began to experiment with refraction, which is the bending of light as it passes from one medium to another. According to ibn al-Haitham, if vision is what happens when light passes from an object and into the eye, it is likely to bend once it enters the eye. This refracted light could lead to a distorted image, so ibn al-Haitham performed many experiments to see if it was possible for light to transfer from one medium to another without being bent.

  Ibn al-Haitham’s other main contribution to optics was in suggesting that the mathematics of optics – such as reflection and refraction – need to be consistent with what we know about the biology of the eye. This was all groundbreaking stuff, and his theory of vision was enormously influential. And, as was often the case, it was more influential among Western scientists than those in his own region. Our current understanding of vision did not come directly from ibn al-Haitham, but what is not in doubt is that he was among the first to demonstrate critical flaws in the extramission theory.

  Back to school

  The consensus among historians is that the astronomer from Germany, Johannes Kepler, to whom we owe much of our knowledge of optics and astronomy, leant on ibn al-Haitham’s work, which was widely available in Latin in the 16th and 17th centuries.

  By the 16th century, scientists in Western Europe such as Kepler would have likely studied in or worked at universities. Universities in Western Europe began to appear in the middle ages. The university of Siena, for example, founded in 1240, is one of Western Europe’s oldest seats of learning. Along with Bologna, Cambridge, Oxford, Padua, and Europe’s oldest university in Paris, it helped to revive knowledge and learning in Europe after the middle ages. Yet, to any modern-day visitor from the Middle East or from Asia, the architecture of the oldest universities in Europe mirrors that of many Islamic-era colleges, the first of which were established in Baghdad in the 9th and 10th centuries, and later in Cairo, Egypt. Perhaps the most obvious architectural feature is the presence of a large square or rectangular courtyard, surrounded by teaching rooms at the perimeter.

  The similarities, however, run deeper. Some historians, notably the late George Makdisi, have found intriguing connections between the organisation of learning in Western Europe and that in similar institutions from the Islamic world. Makdisi, for example, discovered that some of the words and concepts commonly used in modern higher education and scientific research today have a connection to an Islamic past.

  Principal among these is the ‘doctorate’, a concept whose origins date back to the time of Europe’s earliest universities. The origins of the doctorate, however, are believed by historians such as Makdisi to lie even earlier still, in a certificate or diploma called a ‘licence to teach and issue legal opinions’. This was awarded by senior teachers in the Islamic world’s colleges to those of their trainees who could demonstrate, after a number of years of study, that they had absorbed enough knowledge to be able to teach their own students. Makdisi discovered that teaching diplomas were used for the same purpose in Bologna and Paris two centuries later.

  Similarities notwithstanding, Europe’s first universities are different from Islamic-era colleges in one important respect. Universities such as Bologna, Oxford and Paris were established with the support of politically powerful churches, and their aims included the need to train new generations of scholar-clerics who were expected one day to hold the reins of power.

  Islam’s early colleges, in contrast, grew out of a movement against state-organised religion – and they were not places where the leading scientists of the day came to work or to study. Almost all of the scientists we have encountered in this book worked directly for caliphs and governors, and were often based inside palace complexes. We have seen that one of these caliphs, al-Mamun, initiated an inquisition, ordering the persecution of intellectuals who refused to accept rationalism within Islam. What is less well known is that once the inquisition failed, those who had resisted the caliph’s demands decided to organise themselves (in the form of guilds) so that they could resist future attempts at governmental meddling in religious learning and interference in who should – or should not – have the right to become a teacher and have students.

  These guilds later gave rise to the first colleges, and the ‘licence to teach’ was designed both to increase the numbers of scholars who could stand up to the state and at the same time to create a curriculum that excluded subjects such as philosophy (and possibly the natural sciences), which would have been identified with al-Mamun ’s policies to enforce a state religious doctrine.

  That is not to say that different Islamic caliphates did not continue to interfere with teaching and learning to pursue their own goals – including science and philosophy. This would still happen, and examples include a network of educational institutions set up in the 11th century by Nizam al-Mulk. These, incidentally, were partly established to counter what the leader saw as the threat from the Ismailis and the Fatimid caliphate. Al-Azhar university in Cairo had already been established by the Fatimids, in part so that they could train their own scholars and theologians in their own more rationalist doctrines.

  If the origins of the doctorate are one day found to lie in the ancient cities of the Middle East, one inescapable conclusion from this is that a key component of our modern research enterprise has roots in two seemingly contradictory aims: the first a desire to free scholarship from state control; the second a desire to stop young people from innovating and experimenting with ideas, and instead to steer them in the direction of traditional thinking.

  A second conclusion might be even more troubling. As we shall see in the next chapter, Europe’s nations used learning – both scientific research and higher education – in the service of colonisation. If Islam’s colleges were the forerunners to Europe’s universities, could it be said that Islamic-era science and learning had a small part to play in the colonial project?

  Acknowledging the past

  As can be seen in this chapter and elsewhere in the book, scientists from the Islamic era were generous – perhaps a little over-generous – in acknowledging that their knowledge of optics, astronomy, medicine and much else had in fact been developed elsewhere, especially India and ancient Greece. What the Western world calls Arabic numerals are known as ‘Indian numerals’ in the Arabic language, and what is known in the Western world as Islamic medicine is known in Muslim countries as Greek (or Unani) medicine.

  Yet, when it was Europe’s turn, not all in the research fraternity were willing to repay the compliment and acknowledge that some of the ideas being worked on in the 15th and 16th centuries had come to Europe from the empires of non-Western cultures. Such a lack of citation was not universal, and it proved less of an issue in the fields of optics, algebra and chemistry. As we have seen, controversy is greater over the extent to which Islamic-era astronomy, medicine and the organisation of learning was adopted in Europe.

  In his book Islam and the Destiny of Man, the British writer and former diplomat Charles Le Gai Eaton argues that the present time (in which the nations of Islam and the post-Christian world are mostly at peace) is unusual. For most of the past, he says, the relationship between the two has been characterised by wars and by mistrust. These wars span literally centuries of conflict between Islam’s early caliphates and Byzantium, followed by centuries of Crusades, and followed after that by centuries of fighting between Eur
opean states and the Ottoman empire, right up to the 20th century and the end of the First World War.

  Such a long and sustained history of warfare may offer one explanation as to why the institutions of Europe would have been reluctant to acknowledge the validity of (or cite) Islamic-era learning. One way of understanding this relationship is to consider what happened during the Cold War and its aftermath. Even if they had wanted to, scientists from East and West weren’t able to acknowledge each others’ work because of the deep hostilities that existed between the United States and the former Soviet Union.

  A more relevant example, however, can be found in the reception of the medicine of ibn-Sina in Renaissance Europe. The Canon of Medicine has arguably had the greatest worldwide impact of any medical textbook in the pre-modern world. It dominated medical teaching and research for more than five centuries, and in doing so it changed how medicine was performed in Latin Europe. At the same time, however, ibn-Sina was sometimes harshly attacked by commentators in Western Europe, both for his medicine and also for the fact that he was from a different religion.

  Much science and medicine arrived in Europe in Arabic through Spain – specifically via a translation school in the city of Toledo. But quite how the Canon got into university curricula is not clear. The first known Latin translation was by Gerard of Cremona in the 12th century. This translation became the standard text in Western Europe – very few saw any reason to go back to the Arabic original after that.

  The Canon was taught to budding medics in France, Germany, Italy and Spain at universities including Bologna, Montpellier, Padua, Paris and, later, Tübingen. Thanks to the painstaking work of New York-based historian Nancy Siraisi, we know of the existence of 60 separate editions that were in circulation between 1500 and 1674.