Science and Rationalism in 9th Century Baghdad

Text of the Lecture of Professor Jim Al-Khalili in the Conference Muslim Heritage in our World: Social Cohesion marking the 1001 Inventions Exhibition at the House of Parliament, 15th of October 2008, Church House, London, UK.

Professor Jim Al-Khalili*

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Professor Jim Al-Khalili

Text of the Lecture of Professor Jim Al-Khalili in the Conference Muslim Heritage in our World: Social Cohesion marking the 1001 Inventions Exhibition at the House of Parliament, 15th of October 2008, Church House, London, UK.

We live in an age when rational thought is under attack from irrationality, superstition and pseudo-scientific ideas. I do not mean by this anything necessarily to do with the religion of Islam, but rather the threat in the West from irrational beliefs such as alternative therapies, New Age nonsense and, most worryingly, Creationism.

When a potential Vice President (and hence President) of the most powerful nation in the world believes that dinosaurs roamed the Earth just a few thousand years ago, and that the Universe itself was created in 4000 BC, then I really worry.

We have recently heard in the news of a prominent scientist at the Royal Society making what were in my view quite sensible comments about how we, as scientists and science educators, should engage with those children whose religion conflicts with the science taught in the classroom. He was subsequently forced to resign his position as education secretary at the Royal Society because of a backlash from hard-line atheists as the battle lines are being drawn. This is particularly important now as next year we celebrate the 200 anniversary of the birth of Charles Darwin and so debates and discussions about his theory of evolution will be taking place all over the world.

As a scientist myself (I am a theoretical nuclear physicist, I am naturally of the strong opinion that the greatest idea that the human race ever came up with is the notion of the scientific method. This idea gives us the only rational way of finding out how our universe works and what our place in it is. The knowledge that humanity has gained from a rational scientific understanding of the Universe, gives us far more than just ‘one way of viewing the world’.

Progress, through reason and rationality, is by definition a good thing; knowledge and enlightenment are always better than ignorance. On the other hand, I respect the views of those who hold religious beliefs. I see the value and importance, to them, of their faith, even if I do not share it. I see the cultural, historical and psychological value of religion even if I do not share its spiritual dimensions. But many have worried that science and religion are therefore incompatible. So I would like to describe a period in history when science and religion coexisted in harmony like never before or since, anywhere in the world.

You see, I was born in Baghdad, to an English mother and Iraqi father. And despite my education being in Britain (at least from the age of 16) I still have cultural interest in the Golden Age of Islam, when science flourished, particularly during the time the early ‘Abbāsid caliphate that had Baghdad as its capital. It is often claimed that what we define as the modern scientific method wasn’t established until the European Renaissance, by the likes of Francis Bacon and René Descartes in the 17th century. But dig a little into history that is not so blatantly Eurocentric and you find that in fact all the ingredients of the scientific method –investigating phenomena, acquiring new knowledge, correcting and integrating previous knowledge based on the gathering of data through observation and measurement, followed by the formulation and testing of hypotheses to explain the data – there is no doubt that this actually began 600 years earlier in Iraq, thanks to an incredible genius called Ibn al-Haytham (known in the West by his Latinized name Alhazen).

Certainly, the early Muslim thinkers were quite clear about their mission, for the Qur’ān required all Muslims to study the skies and the earth to find proof of their faith. The Prophet himself urged his disciples to seek knowledge ‘from the cradle to the grave’, no matter how far that search took them. Of course, this knowledge (‘ilm) referred primarily to theology, but in its early years, Islam made no distinction between religious and non-religious scholarly pursuits. And not all the scientific work was carried out by Muslims. Important contributions were also made by Christian and Jewish scholars, particularly in the early days of the ‘Abbāsid era, when the main body of translation from Greek texts was carried out. This was made possible because the political climate in Baghdad at the time was dominated by a movement of Islamic rationalists, who sought to combine faith and reason. Their theological view was supported by the caliphate, which led to a spirit of tolerance by the ‘Abbāsids of other faiths, and an inclusiveness of other cultures, in which scientific enquiry was encouraged.

Now, we are taught at school that Isaac Newton is the undisputed father of modern optics. School science books abound with his famous experiments with lenses and prisms, his study of the nature of light and its reflection, and the refraction and decomposition of light into the colours of the rainbow. In fact, it is Ibn al-Haytham who is the true father of optics. He famously explained how vision works by light entering our eyes rather than being emitted from the eye to shine on the objects we see, as was believed to be the case by many of the Greek philosophers. He went on to describe reflection and refraction, and invented the pinhole camera.

Many sciences flourished during this Golden Age between the 9th and 12th centuries, and even continued for several hundred years later. For instance, Islamic mathematicians inherited the Indian decimal system and extended it to describe fractions. The very word ‘algebra’ comes from the Arabic al-jabr, which appears in the title of a book written by Al-Khwārizmī, a Persian from modern day Uzbekistan who worked in Baghdad in the 9th century. And he wasn’t the only famous scholar to have come from that part of the world.

Read most popularisations of the history of astronomy and you will very likely find that apparently nothing happed of note between the Greek, Ptolemy, in the 2nd century CE and the Polish Renaissance astronomer, Copernicus in the 16th. The reason is simple: Ptolemy believed that the sun went round the earth. Copernicus is credited with correctly explaining that is in fact the other way round. But we now know that the Copernican revolution would not have taken place without the work of Syrian and Persian astronomers hundreds of years before him.

In physics, I have mentioned the work of Ibn al-Haytham in optics. In addition, many feats of engineering involving valves, vacuums, pullies and levers needed a solid understanding forces and mechanics. In his famous Mas’ūdī Canon, the great al-Bīrūnī employed mathematical techniques and basic calculus for the first time to describe motion and acceleration, thereby laying the foundations for Newton’s laws of motion in his Principia over six hundred years later.

One field in particular that can truly be said to have begun at this time is chemistry. The word ‘alchemy’ itself derives directly from al-kīmyā’, the Arabic word for ‘chemistry’. And it is a lonely scholar by the name of Jābir ibn Hayyān whom we must thank for single-handedly creating what we would regard as modern chemistry. Many other words in chemistry like ‘alcohol’ and ‘alkali’ derive from the Arabic during his time.

In medicine, Al-Rāzī who lived in Baghdad in the 9th century wrote a medical encyclopaedia that was translated into Latin and became one of the most highly respected and frequently used medical textbooks in Europe. He made contributions to gynaecology, obstetrics and ophthalmic surgery. He was also the first to study psychology and psychotherapy and ran the psychiatric ward in a Baghdad hospital at a time when, in the Christian world, the mentally ill would have been regarded as being possessed by the devil.

An extremely fascinating topic that it is important to explore carefully is that ‘Abbāsid scientists developed rudimentary theories on evolution and natural selection. A biologist of East African decent born in Basra in Southern Iraq around 781, was a man called Al-Jāhith. In his Book of Animals, he first speculated on the influence of the environment on animals. Given the importance of Darwinian natural selection and the continuing strong feelings it provokes, it seems astonishing to me that Al-Jāhith’s work, although extremely rudimentary and by no means undermining the genius of Darwin has been largely ignored, particularly in the Islamic world.

So why did this wonderful era end? Well, there were many complex reasons. And the decline was far slower than many in the West realise. It did not end suddenly in the 13th century when the Mongols invaded. It certainly did not end due to a sudden turn towards a more conservative mystical version of Islam, although we cannot deny that this happened. Other reasons include weaker leaders, fragmentation of the Empire and the later colonialism by Europeans.

But the fact is that today, just as we see in many parts of the Christian world, we sometimes see an unhealthy anti-scientific attitude in many Muslim countries. I recently had the opportunity of reading two medieval Arabic medical texts in preparation for a forthcoming BBC series on science and Islam I am making. One was Ibn Sīna’s (Avicenna) Canon of Medicine, dating back to the 11th century, the other, called the Prophet’s Medicine, from the 14th century. While Ibn Sīnā’s contained some treatments and cures we would find silly today, such as bloodletting, it was at least a serious attempt at a proper understanding of physiology, anatomy and disease and was required reading in Europe for almost seven hundred years. The other book, written 300 years later, showed a huge step backwards in thinking and contained many irrational ideas, such as treating epilepsy by the exorcism of the evil spirits.

It seems that in many ways, thinking and scholarship in Medieval Islam a thousand years ago was far more rational, open and enquiring than many of the attitudes we see today, and I don’t just mean in the Islamic world but the so-called civilised West as well. Early Islam can certainly teach us a lesson or two on tolerance, inclusiveness and a spirit of enquiry based on open and rational thought – and by ‘us’ I mean all cultures today. Cultural cohesion is possible.

* Professor of Physics and Professor of the Public Engagement in Science at the University of Surrey, UK