0:00:10 > 0:00:17My name is Jim Al-Khalili and I'm a professor of physics at the University of Surrey.
0:00:19 > 0:00:25Studying the innermost secrets of atoms and their nuclei has been at the heart of my working life.
0:00:27 > 0:00:30But there's another side to me...
0:00:40 > 0:00:43I was born and grew up in Baghdad,
0:00:43 > 0:00:46to an English mother and an Iraqi father,
0:00:46 > 0:00:49but left Iraq with my family in the late '70s
0:00:49 > 0:00:51when Sadam Hussain came to power.
0:00:53 > 0:00:57By then, science was already my great passion in life.
0:00:57 > 0:01:00As I studied it further, I saw myself fully part
0:01:00 > 0:01:05of the Western tradition, inspired by names like Newton and Einstein.
0:01:10 > 0:01:16But buried away was this nagging feeling that I was ignoring part of my own scientific heritage.
0:01:19 > 0:01:26I still remembered my schooldays in Iraq and being taught of a golden age of Islamic scholarship.
0:01:26 > 0:01:29That between the 9th and 12th centuries,
0:01:29 > 0:01:32a great leap in scientific knowledge
0:01:32 > 0:01:36took place in Baghdad, Damascus, Cairo and Cordoba.
0:01:36 > 0:01:39So, I want to unearth this buried history
0:01:39 > 0:01:41to discover its great figures
0:01:41 > 0:01:46and to assess exactly what their contribution to science really was.
0:01:46 > 0:01:49Are there medieval Muslim scientists who should be spoken of
0:01:49 > 0:01:53in the same breath as Galileo, Newton and Einstein?
0:01:53 > 0:01:57And crucially, what is the relationship
0:01:57 > 0:01:59between science and Islam?
0:02:23 > 0:02:27My journey into the science of the medieval Islamic world
0:02:27 > 0:02:30will take me through Syria, Iran and North Africa.
0:02:36 > 0:02:40'I started in the backstreets of the Egyptian capital Cairo,
0:02:40 > 0:02:48'with the realisation that that the language of modern science still has many references to its Arabic roots.
0:02:50 > 0:02:55'Take scientific terms like algebra, algorithm, alkali.
0:02:55 > 0:02:59'I instantly recognise these words as Arabic.
0:03:00 > 0:03:04'And these are at the very heart of what science does.
0:03:04 > 0:03:08'There would be no modern mathematics or physics without algebra.
0:03:08 > 0:03:15'No computers without algorithms and no chemistry without alkalis.
0:03:21 > 0:03:28'Surprisingly few people in the west today, even scientists, are aware of this medieval Islamic legacy.
0:03:28 > 0:03:31'But it wasn't always so.
0:03:32 > 0:03:35'From the 12th to the 17th century,
0:03:35 > 0:03:41'European scholars regularly refer to earlier Islamic texts.'
0:03:41 > 0:03:49I have here copies of some pages of the book Liber Abacci by the great Italian mathematician,
0:03:49 > 0:03:52Leonardo Pisano, otherwise known as Fibonacci.
0:03:52 > 0:03:58What's fascinating is that on page 406 is a reference to an older text
0:03:58 > 0:04:02called "modum algebre et almuchabale'
0:04:02 > 0:04:05and in the margin is the name Maumeht,
0:04:05 > 0:04:09which is the Latinised version of the Arabic name, Mohammed.
0:04:09 > 0:04:15The person he's referring to is Mohammed ibn Musa Al-Khwarizmi.
0:04:18 > 0:04:23In fact, Arabic names crop up in many medieval European texts
0:04:23 > 0:04:27on subjects as varied as map-making, optics and medicine.
0:04:32 > 0:04:35But I want to start with Al-Khwarizmi, because his work
0:04:35 > 0:04:39touches on a crucial aspect of all our lives today.
0:04:42 > 0:04:49It's thanks to Al-Khwarizmi that the European world realised that their way of doing arithmetic,
0:04:49 > 0:04:52which was still essentially based on Roman numerals,
0:04:52 > 0:04:56was hopelessly inefficient and downright clunky.
0:04:57 > 0:05:01If I asked you to multiply 123 by 11,
0:05:01 > 0:05:05you may even be able to do it in your head.
0:05:05 > 0:05:09The answer is 1,353.
0:05:09 > 0:05:13But try doing it with Roman numerals,
0:05:13 > 0:05:16you'd have to multiply CXXIII by XI.
0:05:16 > 0:05:20It can be done, but trust me, it's not fun.
0:05:24 > 0:05:26Al-Khwarizmi showed Europeans
0:05:26 > 0:05:29that there's a better way of doing arithmetic.
0:05:29 > 0:05:36In his book entitled The Hindu Art Of Reckoning, he describes a revolutionary idea.
0:05:36 > 0:05:39You can represent any number you like
0:05:39 > 0:05:41with just ten simple symbols.
0:05:45 > 0:05:50This idea of using just ten symbols, the digits from one to nine,
0:05:50 > 0:05:54plus a symbol for zero to represent all numbers from one to infinity
0:05:54 > 0:05:58was first developed by Indian mathematicians
0:05:58 > 0:06:04around the 6th century and I can't overstate its importance.
0:06:04 > 0:06:08Here are the numbers in Indian Arabic numerals.
0:06:08 > 0:06:12Wahid, ithinin, thalatha, arba'a,
0:06:12 > 0:06:16khamsa, sita, saba'a, thamania, tisa'a.
0:06:16 > 0:06:19And here are the numbers we're more familiar with in the West.
0:06:19 > 0:06:22One, two, three, four, five,
0:06:22 > 0:06:25six, seven, eight, nine.
0:06:25 > 0:06:29And you can see the similarity between these numbers
0:06:29 > 0:06:32and particularly between the numbers two and three.
0:06:32 > 0:06:34If I tip this sideways,
0:06:34 > 0:06:38you can see how they look like numbers two and three.
0:06:38 > 0:06:43And what's powerful about these digits, this numerical system
0:06:43 > 0:06:47is how it simplifies arithmetic calculations.
0:06:47 > 0:06:55'But Al-Khwarizmi and his colleagues went further than just translating the Indian system into Arabic.
0:06:55 > 0:06:57'They created the decimal point.'
0:06:59 > 0:07:03This text, written just a century after Al-Khwarizmi's,
0:07:03 > 0:07:05is by a man we know only as Al-Uqlidisi.
0:07:05 > 0:07:09Here he shows that the same decimal system
0:07:09 > 0:07:14can be extended to describe not just whole numbers but fractions as well.
0:07:14 > 0:07:19The infinity of possibilities that lie in between the integers.
0:07:19 > 0:07:21Here is a copy of Al-Uqlidisi's manuscript
0:07:21 > 0:07:24where he showed how the decimal point
0:07:24 > 0:07:26is used for the very first time.
0:07:26 > 0:07:28He describes it by using a dash.
0:07:28 > 0:07:31Here are the digits 17968,
0:07:31 > 0:07:36and there's a small dash over the nine indicating the decimal place.
0:07:36 > 0:07:41The idea of the decimal point is so familiar to us,
0:07:41 > 0:07:45that it's hard to understand how people managed without it.
0:07:45 > 0:07:46Like all great science,
0:07:46 > 0:07:50it's blindingly obvious after it's been discovered.
0:08:00 > 0:08:04'The story of numbers and the decimal point hints
0:08:04 > 0:08:09'that even 1,000 years ago science was becoming much more global.
0:08:10 > 0:08:14'Ideas were spreading, emerging out of India, Greece or even China
0:08:14 > 0:08:15'and cross-fertilising.
0:08:18 > 0:08:22'And looking on a map that shows where people lived 1,000 years ago
0:08:22 > 0:08:26'gave me my first insight into why medieval Islam
0:08:26 > 0:08:30'would play such an important role in the development of science.
0:08:32 > 0:08:37'Now look at which city lies at the centre of the known world,
0:08:37 > 0:08:41'a place where the widest range of peoples and ideas
0:08:41 > 0:08:43'were bound to collide.
0:08:43 > 0:08:46'It's the city where I was born,
0:08:46 > 0:08:49'the capital of the Islamic empire, Baghdad.
0:08:56 > 0:08:59'Recent events mean I can no longer visit the city,
0:08:59 > 0:09:06'but these are the home movies of my cousin Farris, filmed in the 60s.
0:09:06 > 0:09:09'The Baghdad we knew then looked nothing
0:09:09 > 0:09:11'like the bomb-wrecked city it is now.
0:09:11 > 0:09:14'I certainly grew up proud to be associated
0:09:14 > 0:09:17'with one of the world's greatest cities.
0:09:20 > 0:09:27'Baghdad was founded in 762 AD by the caliph Al-Mansur.
0:09:27 > 0:09:31'His aim was to make it the glorious capital of a brand new empire
0:09:31 > 0:09:35'united by Islam, the rising religion of the time.'
0:09:38 > 0:09:42The Abbasid caliphs had claimed their right to rule by declaring
0:09:42 > 0:09:46that they were directly related to the prophet Mohammed,
0:09:46 > 0:09:49who had founded the new religion over 100 years earlier.
0:09:49 > 0:09:52But in that short time,
0:09:52 > 0:09:57the armies of Islam had conquered a vast territory.
0:10:00 > 0:10:02Starting in a small area around Medina,
0:10:02 > 0:10:05they moved rapidly out of the Arabian peninsula
0:10:05 > 0:10:10and within a few decades had taken control of the Levant,
0:10:10 > 0:10:12North Africa, Spain and Persia.
0:10:14 > 0:10:16I think one must bear in mind that this is an era
0:10:16 > 0:10:18in which people believed in God,
0:10:18 > 0:10:21and the dramatic successes of the Arabs
0:10:21 > 0:10:23as they poured out of Arabia
0:10:23 > 0:10:26were such that a lot of people did observe
0:10:26 > 0:10:29and say they must have God on their side.
0:10:29 > 0:10:32This must be the true god, and some people did convert,
0:10:32 > 0:10:34or if they didn't convert,
0:10:34 > 0:10:39they did submit to Arab-Muslim political control for that reason.
0:10:41 > 0:10:48By the early 8th century, Islamic caliphs ruled a vast territory.
0:10:48 > 0:10:52And like most successful emperors, from Caesar to Napoleon,
0:10:52 > 0:10:55they understood that political power
0:10:55 > 0:10:58and scientific know-how go hand in hand.
0:11:03 > 0:11:07There were many reasons for this. Some were practical.
0:11:07 > 0:11:09Medical knowledge could save lives.
0:11:09 > 0:11:12Military technology could win wars.
0:11:12 > 0:11:16Mathematics could help deal with the increasing complexities
0:11:16 > 0:11:17of the finances of state.
0:11:17 > 0:11:21Islam as a religion also played a pivotal role.
0:11:21 > 0:11:24The prophet himself had told believers to seek knowledge
0:11:24 > 0:11:28wherever they could find it, even if they had to go as far as China.
0:11:28 > 0:11:31And many Muslims, I'm sure, felt that to study
0:11:31 > 0:11:36and better understand God's creation was in itself a religious duty.
0:11:36 > 0:11:40But there were other less edifying motives at play.
0:11:40 > 0:11:44To many in the ruling elite of the Islamic Empire,
0:11:44 > 0:11:47knowledge itself had a self-serving purpose.
0:11:47 > 0:11:52Because possessing it was seen as proof of the new empire's superiority
0:11:52 > 0:11:54over the rest of the world.
0:11:59 > 0:12:05But with military and political success, the Islamic caliphs faced an inevitable problem.
0:12:06 > 0:12:10How do you sensibly govern a hugely diverse population?
0:12:12 > 0:12:15Although some of the empire had converted to Islam,
0:12:15 > 0:12:18they were still separated by huge distances
0:12:18 > 0:12:23and adhered to many different traditions and languages.
0:12:24 > 0:12:30In the 8th century AD, the empire's leader, Caliph Abdul Malik,
0:12:30 > 0:12:35had to find a way of administering this mish-mash of languages.
0:12:35 > 0:12:41Like all the great figures of the Islamic empire, Al-Malik lived in a culture without portraiture.
0:12:41 > 0:12:46All we have are later impressions of what he might have looked like.
0:12:46 > 0:12:49His solution was sweeping in scale
0:12:49 > 0:12:51and, inadvertently,
0:12:51 > 0:12:54laid the foundations of a scientific renaissance.
0:12:55 > 0:13:00It was this Abdul Malik who said this bureaucratic chaos has to stop.
0:13:00 > 0:13:04We cannot continue to run the government
0:13:04 > 0:13:10and govern all this span of land with this tower of Babel languages.
0:13:10 > 0:13:14He wanted to govern it with a uniform language
0:13:14 > 0:13:18and that language was one he wanted to understand,
0:13:18 > 0:13:20so he demanded that it be in Arabic.
0:13:26 > 0:13:32But the choice of Arabic as the common language of the Empire went beyond administrative convenience.
0:13:34 > 0:13:38The decision had extra force and persuasiveness,
0:13:38 > 0:13:40because Islam's holy book the Qur'an
0:13:40 > 0:13:44is in Arabic, and Muslims therefore consider Arabic
0:13:44 > 0:13:46to be the language of God.
0:13:58 > 0:14:01The words of the Qur'an are so sacred
0:14:01 > 0:14:05that its text hasn't changed in over 1,400 years.
0:14:05 > 0:14:10By comparison, English has changed dramatically in just 700 years.
0:14:10 > 0:14:14To our ears, Chaucer is almost unintelligible,
0:14:14 > 0:14:19whereas any Qur'an can be understood by anyone who reads Arabic.
0:14:24 > 0:14:28Making copies of the Qur'an has always been a specialised
0:14:28 > 0:14:33and highly respected job since the foundation of Islam.
0:14:33 > 0:14:38Calligraphy expert Nayef Scaf, who lives in the Syrian capital
0:14:38 > 0:14:43Damascus, writes for mosques and in madrasahs all over the country.
0:14:44 > 0:14:48These are words he's found himself writing over and over again.
0:14:48 > 0:14:51Words of great significance for Muslims.
0:14:51 > 0:14:55They're the opening line to each chapter in the Qur'an.
0:14:55 > 0:15:01So, what it says is, "Bismi llahi ar-rahman ar-rahim,
0:15:01 > 0:15:03which means, "In the name of God
0:15:03 > 0:15:06"the most gracious and the most merciful."
0:15:06 > 0:15:09HE SPEAKS ARABIC
0:15:14 > 0:15:19He's saying that the complexity of Arabic calligraphy
0:15:19 > 0:15:22was enforced onto them because of the spread of Islam,
0:15:22 > 0:15:26because they were worried that the meaning of the words
0:15:26 > 0:15:28in the Qur'an would be lost.
0:15:28 > 0:15:32If it was read by people who don't speak Arabic not only would they misinterpret it,
0:15:32 > 0:15:35they wouldn't be able to distinguish between letters.
0:15:35 > 0:15:38So, not only did they add dots on certain letters,
0:15:38 > 0:15:41but also lots of squiggly lines
0:15:41 > 0:15:44which change the sound of the vowels.
0:15:44 > 0:15:47It was something they put into place to ensure that people were
0:15:47 > 0:15:51able to have the right pronunciation when they read the Qur'an.
0:15:55 > 0:15:58The consequences for science were immediate.
0:15:58 > 0:16:00Scholars from different lands
0:16:00 > 0:16:04who previously had no way of communicating
0:16:04 > 0:16:06now had a common language.
0:16:06 > 0:16:10And it was a language that was specially developed to be precise
0:16:10 > 0:16:17and unambiguous, which made it ideal for scientific and technical terms.
0:16:17 > 0:16:20What this meant was the summoning into existence
0:16:20 > 0:16:23of a vast intellectual community,
0:16:23 > 0:16:27where scholars from very different parts of the world
0:16:27 > 0:16:30could engage in dialogue, comparison, debate, argument,
0:16:30 > 0:16:33often very fierce argument with each other.
0:16:33 > 0:16:39It was possible for scholars based in Cordoba in southern Spain
0:16:39 > 0:16:42to engage in literary and scientific debate
0:16:42 > 0:16:45with scholars from Baghdad or from Samarkand.
0:16:52 > 0:16:56But I can tell you that scholars aren't motivated by the love of knowledge alone.
0:16:56 > 0:17:01There's nothing like a large hunk of cash to focus the mind.
0:17:03 > 0:17:07By the early 800s, the ruling elite of the Islamic empire
0:17:07 > 0:17:11were pouring money into a truly ambitious project,
0:17:11 > 0:17:13which was global in scale
0:17:13 > 0:17:15and which was to have a profound impact on science.
0:17:18 > 0:17:21It was to scour the libraries of the world for scientific
0:17:21 > 0:17:25and philosophical manuscripts in any language,
0:17:25 > 0:17:28Greek, Syriac, Persian and Sanskrit,
0:17:28 > 0:17:33bring them to the empire and translate them into Arabic.
0:17:33 > 0:17:37This became known as the translation movement.
0:17:50 > 0:17:56The effort scholars put into finding ancient texts was astonishing.
0:17:56 > 0:18:00And one key reason for this is that bringing a book to the caliph,
0:18:00 > 0:18:05which he could add to his library, could be extremely lucrative.
0:18:05 > 0:18:09The story goes that the caliph al-Ma'mun was so obsessed
0:18:09 > 0:18:12that he'd send his messengers out of Baghdad,
0:18:12 > 0:18:15far and wide to distant lands, just to get hold of books
0:18:15 > 0:18:18that he didn't possess, for the translation movement.
0:18:18 > 0:18:22And anyone who brought him back a book that he didn't have,
0:18:22 > 0:18:24he'd repay them its weight in gold.
0:18:25 > 0:18:31To give some sense of the extent of the activities between 750 and 950,
0:18:31 > 0:18:36somebody called Al Nadim, who wrote a list of the intelligentsia
0:18:36 > 0:18:40of the Abbasid era, lists 70 translators,
0:18:40 > 0:18:44so it was quite a large cohort of people involved in translations.
0:18:44 > 0:18:48And obviously, he only named the well-known translators.
0:18:48 > 0:18:51They could get up to 500 gold dinars a month,
0:18:51 > 0:18:54which is probably around 24,000.
0:18:54 > 0:18:57Which is a huge sum of money for what they were doing.
0:18:57 > 0:19:02It was a very prestigious, well-paid, well-patronised activity.
0:19:04 > 0:19:09And motivating this global acquisition of knowledge
0:19:09 > 0:19:11was a pressing practical concern,
0:19:11 > 0:19:14one that rarely crosses our minds today.
0:19:15 > 0:19:19This is the new Library at Alexandria, in Egypt.
0:19:19 > 0:19:23But fresh in the memory of many in the empire was the story
0:19:23 > 0:19:26of the destruction of the original library
0:19:26 > 0:19:28at Alexandria centuries earlier,
0:19:28 > 0:19:32and the shocking loss of thousands of years of accumulated knowledge.
0:19:34 > 0:19:37One of the things that we tend to forget,
0:19:37 > 0:19:40because we live in a age of massive information storage
0:19:40 > 0:19:44and perfect communication more or less,
0:19:44 > 0:19:49is the ever present possibility of total loss.
0:19:49 > 0:19:53That was very important for Islamic scholars.
0:19:53 > 0:19:59They knew extremely well that writings could be forgotten
0:19:59 > 0:20:04or buried or burnt or destroyed, that cities could pass away.
0:20:04 > 0:20:07What we see in Baghdad or Cairo or Samarkand
0:20:07 > 0:20:12is exactly the gathering together and translation, analysis,
0:20:12 > 0:20:17accumulation, storage and preservation of material
0:20:17 > 0:20:21which they were well aware could be lost forever.
0:20:34 > 0:20:40And if there was one branch of knowledge that everyone from the mighty caliph to the humble trader
0:20:40 > 0:20:43wanted to preserve and enhance, it was medicine.
0:20:47 > 0:20:51These were, after all, times when few lived to old age.
0:20:51 > 0:20:55Writings from the time remind us that what we might consider
0:20:55 > 0:21:00a relatively minor infection today could be a death sentence.
0:21:00 > 0:21:05Religious teachings then were not just a source of comfort.
0:21:05 > 0:21:09They were a constant reminder that we should never give up.
0:21:09 > 0:21:14In the Hadith which is the collected sayings of the Prophet Mohammed,
0:21:14 > 0:21:19- it says.... - HE READS ARABIC
0:21:19 > 0:21:23Which means that God didn't send down a disease
0:21:23 > 0:21:25without also sending down a cure.
0:21:28 > 0:21:32It's statements like this that lead Muslims, even today, to believe
0:21:32 > 0:21:36that cures for all diseases are out there somewhere
0:21:36 > 0:21:39and that we need to search to find them.
0:21:40 > 0:21:46'To assess how this optimism actually affected Islamic medicine,
0:21:46 > 0:21:51'I met up with Dr Peter Pormann in the Syrian capital, Damascus.
0:21:51 > 0:21:54'He's a leading expert on Islamic Medicine,
0:21:54 > 0:21:57'who spends much of his time researching
0:21:57 > 0:21:58'here in the Middle East.'
0:21:58 > 0:22:00What people don't realise is that the history
0:22:00 > 0:22:04of Islamic medicine is really the history of our medicine,
0:22:04 > 0:22:07because our medicine, the university medicine,
0:22:07 > 0:22:09we used until the 19th century,
0:22:09 > 0:22:13it was based to a large extent on the work of all these Islamic physicians.
0:22:17 > 0:22:21Islamic medicine built extensively on the foundations
0:22:21 > 0:22:23laid by the ancient Greeks.
0:22:25 > 0:22:29The most highly prized and among the first to be translated into Arabic
0:22:29 > 0:22:36were the medical manuscripts of the 3rd century Greek physician, Galen.
0:22:36 > 0:22:40Galen believed that a healthy body was one in balance.
0:22:40 > 0:22:43A balance of four types of fluids called humours,
0:22:43 > 0:22:46which circulate through the body
0:22:46 > 0:22:49and any one of which, if out of balance,
0:22:49 > 0:22:52would cause illness and a change of temperament.
0:22:52 > 0:22:55The four humours were yellow bile,
0:22:55 > 0:23:01which, if in excess, would cause the patient to become bilious
0:23:01 > 0:23:04or bad-tempered and nauseous.
0:23:06 > 0:23:12Blood. Too much of which would cause the patient to become sanguine,
0:23:12 > 0:23:14or cheerful and flushed.
0:23:18 > 0:23:22Black bile, which in excess would cause the patient
0:23:22 > 0:23:26to become lethargic or melancholic or even depressed.
0:23:26 > 0:23:31And...phlegm, which in excess
0:23:31 > 0:23:35would cause the patient to become phlegmatic or apathetic
0:23:35 > 0:23:38and emotionally detached.
0:23:40 > 0:23:44Galen argued that illnesses are caused by an imbalance
0:23:44 > 0:23:45in one of the humours,
0:23:45 > 0:23:50so the cure lies in draining the body of some of that humour.
0:23:50 > 0:23:54He recommended techniques like cutting to induce bleeding
0:23:54 > 0:23:57or using emetics to induce vomiting.
0:23:59 > 0:24:04'But Islamic doctors were acutely aware that Galen and Greek medicine
0:24:04 > 0:24:07'were only one source of medical knowledge.
0:24:10 > 0:24:14'There were other traditions of medicine that they were equally keen
0:24:14 > 0:24:18'to incorporate into their understanding of how the body functioned.
0:24:21 > 0:24:27'Medieval Arabic texts refer to wise women, folk healers who provided medical drugs.
0:24:27 > 0:24:32'This tradition continues today, as I found when I came across one
0:24:32 > 0:24:36'for myself in the back streets of Hammamat in Tunisia.
0:24:38 > 0:24:40'This is Arafez Nabil.
0:24:40 > 0:24:45'She's been running her shop selling medicinal herbs and spices for over 20 years.
0:24:45 > 0:24:48'She believes that her remedies can cure
0:24:48 > 0:24:51'a wide range of medical ailments.'
0:25:36 > 0:25:40'In the backstreets of Tunisia this knowledge is still being used.
0:25:40 > 0:25:47'But medieval Islamic doctors were also aware of other traditions of medicine from China and India.
0:25:54 > 0:25:59'And yet another tradition of medical guidance came from within Islam itself,
0:25:59 > 0:26:02'and takes some of its ideas from the Qur'an
0:26:02 > 0:26:06'and some from the collected sayings of the Prophet, the Hadith.
0:26:07 > 0:26:12'In a bookshop in Monastir in Tunisia, I found a copy
0:26:12 > 0:26:16'of a very popular book available right across the Islamic world.'
0:26:19 > 0:26:22This book is called The Prophet's Medicine
0:26:22 > 0:26:23and you can see how old it is.
0:26:23 > 0:26:28The author was born between 691 and 751 Hijri,
0:26:28 > 0:26:31which places him the 14th century.
0:26:31 > 0:26:34Here's an interesting bit, where it deals with the plague.
0:26:34 > 0:26:37HE READS ARABIC
0:26:44 > 0:26:51It says, "If you come across a land where the plague has come down, then do not enter that land.
0:26:51 > 0:26:55"And if the plague comes down onto your land and you are there,
0:26:55 > 0:26:58"then do not leave your homes in the hope of escaping it."
0:26:58 > 0:27:00So that sort of makes a lot of sense.
0:27:00 > 0:27:03But here's quite an amusing part.
0:27:03 > 0:27:09It deals with epilepsy and it says that the Greeks or Galen believes
0:27:09 > 0:27:15that epilepsy originated in the brain, however they were ignorant.
0:27:15 > 0:27:19They didn't realise the true cause of epilepsy, which is the possession
0:27:19 > 0:27:21of the body by evil spirits.
0:27:21 > 0:27:25And it talks about the cure for epilepsy being exorcism.
0:27:26 > 0:27:29'Hardly scientific.
0:27:29 > 0:27:32'But Islam's most tangible contribution to medicine
0:27:32 > 0:27:34'is less in its specific remedies
0:27:34 > 0:27:37'and more in its over-arching philosophy.
0:27:44 > 0:27:47'It is, after all, a religion whose central idea
0:27:47 > 0:27:50'is that we should feel compassion for our fellow humans.
0:27:55 > 0:27:57'And accompanied by Dr Peter Pormann,
0:27:57 > 0:28:02'I'm going to see a physical, bricks and mortar manifestation
0:28:02 > 0:28:04'of medieval Islamic compassion.
0:28:05 > 0:28:08'This is the Nur al-Din hospital,
0:28:08 > 0:28:11'the leading hospital of the Islamic empire,
0:28:11 > 0:28:14'built here in Damascus and now a museum.'
0:28:14 > 0:28:18THEY GROAN WITH EXERTION
0:28:18 > 0:28:21This was built in the 1150s, 1154, I believe.
0:28:21 > 0:28:24One of the ideas which are stipulated in Islam
0:28:24 > 0:28:28- is the idea to be charitable and charity.- Zakat.
0:28:28 > 0:28:33Exactly, and it's an obligation to give alms and stuff like that.
0:28:33 > 0:28:36So, if you're a ruler or you have a lot of money, what you could do is...
0:28:36 > 0:28:41- You could really be charitable. - ..and set up a nice hospital like this one.
0:28:41 > 0:28:45And within the hospital, Islam actively encouraged
0:28:45 > 0:28:48a high degree of religious tolerance,
0:28:48 > 0:28:52something we take for granted in modern secular society.
0:28:52 > 0:28:55The hospital was open to all communities,
0:28:55 > 0:28:58so you'd have Christians and Jews and Muslims obviously
0:28:58 > 0:29:03and maybe other denominations both as patients and also as practitioners.
0:29:03 > 0:29:08Like a Christian studies with a Muslim, a Muslim says my best student was a Jew,
0:29:08 > 0:29:11and so the medicine which was practised here transcended religion.
0:29:11 > 0:29:14Typically, how many physicians would there be?
0:29:14 > 0:29:18Well, it depends. For certain hospitals,
0:29:18 > 0:29:21- we hear figures of 24 or 28 physicians.- Wow.
0:29:21 > 0:29:23Physicians would do the rounds in the morning.
0:29:23 > 0:29:25Do the prescriptions.
0:29:25 > 0:29:28Things haven't changed over the ages, yeah.
0:29:31 > 0:29:34'As a result of the translation movement
0:29:34 > 0:29:38'those physician now became aware of the latest remedies
0:29:38 > 0:29:40'from as far away as India and China.
0:29:42 > 0:29:46'And as the new drugs filtered in from the rest of the world,
0:29:46 > 0:29:50'hospitals started to set up a new kind of facility
0:29:50 > 0:29:53'within their walls - the pharmacy.'
0:29:53 > 0:29:58So, this notion of a pharmacy in a hospital, is that a new innovation?
0:29:58 > 0:30:01The whole package, certainly that's new, and what is interesting,
0:30:01 > 0:30:05if you look for innovation on the level of pharmacy,
0:30:05 > 0:30:08if you look at Baghdad or even Damascus,
0:30:08 > 0:30:11it's at this crossroad of cultures. So loads of new things come in,
0:30:11 > 0:30:16like musk, for instance, you have Indian drugs, there's an Indian pill, for instance,
0:30:16 > 0:30:19which is good for headaches and bad breath,
0:30:19 > 0:30:23but also gives you sexual appetite, and stuff like that.
0:30:23 > 0:30:25Cures your headache,
0:30:25 > 0:30:30gives you...fresh breath, and gives you...
0:30:30 > 0:30:33So it's like toothpaste, Viagra and aspirin.
0:30:33 > 0:30:36- That's right. All in one.- Fantastic.
0:30:36 > 0:30:38So, let's walk in here.
0:30:38 > 0:30:45'Peter wants to show me perhaps the most ghoulish aspect of Islamic medicine, surgery.'
0:30:45 > 0:30:48Here you have a wonderful illustration.
0:30:48 > 0:30:53This appears to be the first anatomical illustration in history.
0:30:53 > 0:30:57You see it says "adala", which means muscle.
0:30:57 > 0:31:01So, these are the different muscles, which move the eyelids.
0:31:01 > 0:31:07- So it was understood that the muscles controlled the lens and the eye.- Absolutely. Yes. Yeah.
0:31:07 > 0:31:09Move the eyelid, and stuff like that.
0:31:09 > 0:31:12The other thing we have here, which is really nice,
0:31:12 > 0:31:16is we have some ophthalmological instruments,
0:31:16 > 0:31:17for instance it's a hook,
0:31:17 > 0:31:22could be used to pull back your eyelid, that sort of thing.
0:31:22 > 0:31:26These instruments were very useful to the doctor.
0:31:26 > 0:31:33Although these tools might look crude, eye surgery was one of Islamic medicine's great successes.
0:31:33 > 0:31:40One innovation was to improve an older technique for curing cataracts called "couching"
0:31:40 > 0:31:45which, in their hands, had a success rate of over 60%.
0:31:45 > 0:31:47In a living subject, the cornea would be clear.
0:31:47 > 0:31:52Then you'd be able to see the pupil clearly, with the cataract sitting behind the pupil.
0:31:52 > 0:31:59'To see how couching stands the test of time, I'm meeting up with eye surgeon Mr Vic Sharma.'
0:31:59 > 0:32:04The cataract is the lens inside the eye, which sits behind the pupil.
0:32:04 > 0:32:08As with time and age the cataract, the lens gets cloudier and cloudier,
0:32:08 > 0:32:11that's what is referred to as a cataract.
0:32:11 > 0:32:15'I've brought along a replica of a medieval couching knife
0:32:15 > 0:32:19'and a description of the treatment by Albucasis,
0:32:19 > 0:32:25'which is the Latin name for the great 10th-century Islamic surgeon Al-Zahrawi.'
0:32:26 > 0:32:31He says, "You take the couching needle in your right hand, if it be the left eye..." and so on.
0:32:31 > 0:32:35"Then thrust the needle firmly in, at the same time rotating it with your hand
0:32:35 > 0:32:39"till it penetrates the white of the eye and you feel the needle has reached something empty."
0:32:40 > 0:32:42- So, he's talking about how to dislodge.- Exactly.
0:32:42 > 0:32:45So, maybe you can show me. We've got some eyes here.
0:32:45 > 0:32:47Yeah. I'll give it a try.
0:32:47 > 0:32:50And what they would have done is attempted to go in
0:32:50 > 0:32:54by the white of the eye, at the edge,
0:32:54 > 0:32:59where the cornea is, and what they attempted to do was sweep around,
0:32:59 > 0:33:01try to break those ligaments of that lens
0:33:01 > 0:33:04and get the lens to drop away from the pupil,
0:33:04 > 0:33:07to allow more light to enter in through pupil
0:33:07 > 0:33:10and to brighten the subject's vision.
0:33:10 > 0:33:16- You haven't got the capacity to focus.- Yeah, you have no lens now. That was a big problem
0:33:16 > 0:33:19until people starting compensating for that with specs later on.
0:33:19 > 0:33:24Right. What is your feeling about how advanced and successful...?
0:33:24 > 0:33:28Well, they were in the general ball park, the right place.
0:33:28 > 0:33:32They were trying to remove the cataract away from the visual axis.
0:33:32 > 0:33:36They had some understanding of the anatomy of the eye
0:33:36 > 0:33:38and that the lens was behind the pupil
0:33:38 > 0:33:41and that's what was causing the visual loss.
0:33:41 > 0:33:46And so removing that... That general principle is still the same.
0:33:46 > 0:33:50There are accounts of it still being used in certain parts of the world presently.
0:33:56 > 0:34:02'Looking back at medieval Islamic medicine with modern scientific eyes is frustrating.
0:34:02 > 0:34:06'They take as true many things we know to be nonsense,
0:34:06 > 0:34:10'but on the other hand, their desire to deal with this vast subject
0:34:10 > 0:34:13'logically and systematically is admirable
0:34:13 > 0:34:17'and truly marks a break with the past.
0:34:17 > 0:34:20'One Islamic scholar, more than any other,
0:34:20 > 0:34:25'embodies the synthesis of religion, faith and reason.
0:34:25 > 0:34:32'His name was Ibn Sina, or Avicenna, as he's known in the West.
0:34:32 > 0:34:37'He was a polymath who clearly thrived in intellectual and courtly circles.
0:34:37 > 0:34:41'In 1025, he completed this...
0:34:41 > 0:34:46'Al-Qanun fi al-Tibb or the Canon Of Medicine.
0:34:46 > 0:34:49'In it Ibn Sina collated and expanded on all
0:34:49 > 0:34:51'that had gone before him,
0:34:51 > 0:34:57'medical ideas from Greece to India, and turned them into a single work.'
0:34:57 > 0:35:00So how would you place this book in an historical context?
0:35:00 > 0:35:02Oh, it's hugely important.
0:35:02 > 0:35:05There are few books which are as important as the Canon,
0:35:05 > 0:35:09because what this encyclopaedia does, it kind of, you know,
0:35:09 > 0:35:13sweeps away everything else, it becomes a text book,
0:35:13 > 0:35:16it supersedes a lot of other texts.
0:35:16 > 0:35:21People even complain, like, it's so good, it's so tightly organised,
0:35:21 > 0:35:23so easily accessible that, you know,
0:35:23 > 0:35:27people forget to read the Greek sources and the Arabic translations.
0:35:27 > 0:35:32This whole first book, this is the first book, it contains what we call the general principal,
0:35:32 > 0:35:38so it's all about how the human body works, how diseases work in general.
0:35:38 > 0:35:43The second book contains diseases right from tip to toe,
0:35:43 > 0:35:45so he starts with the diseases of the head
0:35:45 > 0:35:52and then he moves down, like the eyes, the ears, the nose, the mouth.
0:35:52 > 0:35:55And he...normally they end up at the sexual organs.
0:35:56 > 0:36:01'At first sight the sheer ambition of the three volumes is hugely impressive.
0:36:01 > 0:36:07'Here's an attempt at diagnosis and cure for diseases
0:36:07 > 0:36:10'as diverse as depression, meningitis and small pox,
0:36:10 > 0:36:14'and there's even detailed chapters on more common problems.'
0:36:14 > 0:36:17So, for instance, here you have, like, headaches.
0:36:17 > 0:36:20Different kinds of headaches.
0:36:20 > 0:36:25HE READS ARABIC
0:36:25 > 0:36:29So, headaches caused by pleasant fragrant smells.
0:36:29 > 0:36:33- And then he's also got, erm... - HE READS ARABIC
0:36:33 > 0:36:36- So, hangovers. - DR PORMANN READS ARABIC
0:36:36 > 0:36:39- Headaches from sex.- Is that right?
0:36:39 > 0:36:43I mean, it hasn't happened to me yet, but I mean, you know...
0:36:43 > 0:36:48Let's see. So the treatment of headache caused by sex.
0:36:48 > 0:36:53HE READS ARABIC
0:36:56 > 0:37:00So if somebody is befallen by,
0:37:00 > 0:37:04suffers from a headache after sex
0:37:04 > 0:37:09and he also has a repletion, like, so he has too many superfluidities or something like that...
0:37:09 > 0:37:13HE READS ARABIC
0:37:13 > 0:37:16He has to first resort to venasection, or blood letting.
0:37:16 > 0:37:19HE READS ARABIC Then you should use purging.
0:37:19 > 0:37:23In... HE READS ARABIC
0:37:23 > 0:37:27For both of them, blood letting and purging are necessary.
0:37:27 > 0:37:30A lot of the stuff in here sounds like nonsense,
0:37:30 > 0:37:34- because this is not modern medicine. - No, it's not.
0:37:34 > 0:37:38How long was this taken seriously?
0:37:38 > 0:37:43Well, the fundamental ideas contained here about how the body works, I mean...
0:37:43 > 0:37:47they hadn't changed until the early 19th century.
0:37:47 > 0:37:50There was progress on certain levels,
0:37:50 > 0:37:53but the essence was the same.
0:37:53 > 0:37:59And then came the big break, with the discovery of bacteria and viruses and things like that.
0:37:59 > 0:38:02From the second half of the 19th century onwards,
0:38:02 > 0:38:04medicine was totally revolutionised.
0:38:05 > 0:38:11'Ibn Sina's Canon of Medicine is a landmark in the history of the subject.
0:38:11 > 0:38:17'Although much of the medical science it espouses we know now to be terribly misguided,
0:38:17 > 0:38:21'its value lies in accumulating the best knowledge in the world
0:38:21 > 0:38:25'at the time into one accessible, organised text.
0:38:25 > 0:38:29'The Canon would give future generations something to rewrite.'
0:38:47 > 0:38:52Cataloguing the world's medical knowledge has clear and obvious benefits.
0:38:52 > 0:38:54But the Islamic empire's obsession
0:38:54 > 0:38:57to uncover the knowledge of the ancients
0:38:57 > 0:39:00went beyond practical matters, like medicine.
0:39:00 > 0:39:02Many, like the Caliph Al-Mamun,
0:39:02 > 0:39:05believed that the people of antiquity
0:39:05 > 0:39:08possessed dark, even magical powers.
0:39:08 > 0:39:13And, what's more, new evidence is coming to light to show just
0:39:13 > 0:39:17how hard Islamic scientists worked to rediscover them.
0:39:27 > 0:39:32'To find out about that story, I have to visit the harsh burnt yellow
0:39:32 > 0:39:34'of the Sahara desert in Egypt.
0:39:34 > 0:39:36'There I am to meet an academic
0:39:36 > 0:39:40'who wants to show me how the translation movement
0:39:40 > 0:39:44'took the Arabs to Egypt on a quest to break a code,
0:39:44 > 0:39:49'which they thought hid the secret of the dark art of alchemy.
0:39:58 > 0:40:03'This is Saqqara, a necropolis, or graveyard, of the ancient pharaohs.
0:40:04 > 0:40:07'Over a ten-acre site, it's a collection of burial chambers
0:40:07 > 0:40:10'and step pyramids that were built
0:40:10 > 0:40:13'in the third millennium before Christ.
0:40:14 > 0:40:18'These are said to be among the oldest stone buildings in the world.
0:40:20 > 0:40:24'Archaeologist Dr Okasha El-Daly is my guide.
0:40:24 > 0:40:30'He was about to reveal the most astonishing story of my journey so far.'
0:40:30 > 0:40:35Oh! Ho ho. Look at that.
0:40:38 > 0:40:41'Like most people, I believed that Egyptian hieroglyphs
0:40:41 > 0:40:45'had remained completely undeciphered until the 19th century.
0:40:45 > 0:40:50'Then came the chance discovery of the famous Rosetta Stone.
0:40:50 > 0:40:53'This stone had the same inscription
0:40:53 > 0:40:55'written in both hieroglyphs and Greek.
0:40:55 > 0:40:57'It provided the crucial clues,
0:40:57 > 0:41:01'which British and French scholars used to decipher
0:41:01 > 0:41:03'the writings of ancient Egypt.
0:41:05 > 0:41:08'That's the usual story one hears.
0:41:08 > 0:41:12'But Dr El-Daly has made a discovery that dramatically alters it.
0:41:13 > 0:41:17'He has recently unearthed a number of rare works
0:41:17 > 0:41:19'by the Islamic scholar Ibn Wahshiyah.
0:41:19 > 0:41:23'What he did was to figure out a correspondence
0:41:23 > 0:41:27'between hieroglyphs like these and letters in the Arabic alphabet.'
0:41:27 > 0:41:35If you look here, for example, at Ibn Wahshiyah's manuscript, he's giving us the Egyptian hieroglyphic signs...
0:41:35 > 0:41:37And Arabic letters underneath.
0:41:37 > 0:41:41Yes. And the phonetic value in Arabic underneath.
0:41:41 > 0:41:44Look very carefully at this one, says "seen" underneath that seat.
0:41:44 > 0:41:46- Yes.- Now, look at this seat here.
0:41:46 > 0:41:53That seat in Egyptian hieroglyphic is used for the sign "S", "seen", which is what you see here, "seen".
0:41:53 > 0:41:55That is the name of the god Osiris.
0:41:55 > 0:41:57- Osiris.- Oh, with an "S".
0:42:00 > 0:42:02This is the letter "H".
0:42:02 > 0:42:05- This one here...- This is the "hah".
0:42:05 > 0:42:10The water wave is the letter "N", or "noon" in Arabic.
0:42:10 > 0:42:15- "T" and the letter "F"...- These are all letters?- These are all letters.
0:42:15 > 0:42:18'But how did he decipher the hieroglyphs?'
0:42:18 > 0:42:22The one good thing about the early Arabic scholars is their ability
0:42:22 > 0:42:26to link ancient Egyptian language, we call hieroglyphics,
0:42:26 > 0:42:28to link it with their own contemporary Coptic.
0:42:28 > 0:42:31They realised that Coptic is nothing
0:42:31 > 0:42:34but the later stage of ancient Egyptian language.
0:42:35 > 0:42:38'They realised this because the translation movement
0:42:38 > 0:42:43'had literally placed hundreds of Coptic texts into their hands.
0:42:43 > 0:42:47'The scholars could now see a direct link
0:42:47 > 0:42:51'between hieroglyphs and Arabic.'
0:42:51 > 0:42:56What fraction of these symbols would have been correctly deciphered?
0:42:56 > 0:43:01They got about 14 letters. They cracked more than half of Egyptian hieroglyphics.
0:43:01 > 0:43:05So, that was a remarkable achievement for people of the 10th century.
0:43:10 > 0:43:16Well, that's probably the biggest revelation for me so far on my travels,
0:43:16 > 0:43:20that Egyptology didn't begin in the 19th century.
0:43:20 > 0:43:23Yet again, it seems that Islamic scholars
0:43:23 > 0:43:29actually cracked hieroglyphics and they cracked it for strange reasons.
0:43:29 > 0:43:33They cracked it because they were interested in astrology and alchemy.
0:43:33 > 0:43:38But here is another example of this amazing translation movement.
0:43:38 > 0:43:42They weren't just translating Greek and Indian and Persian texts,
0:43:42 > 0:43:45they were translating Egyptian hieroglyphics as well.
0:43:45 > 0:43:47Absolutely incredible.
0:43:51 > 0:43:55'Unfortunately for the Caliph Al-Mamun,
0:43:55 > 0:43:59'the hieroglyphs contained no alchemical secrets.
0:43:59 > 0:44:04'But what this story reveals to me is the insatiable curiosity
0:44:04 > 0:44:07'Islamic scholars had about the world.
0:44:07 > 0:44:09'They were desperate to absorb knowledge
0:44:09 > 0:44:12'from all cultures purely on merit,
0:44:12 > 0:44:17'with no qualms about the places or religions from which it came.'
0:44:17 > 0:44:22Most intellectual traditions, including, if I may say so, our own,
0:44:22 > 0:44:25tend to work very hard to keep everybody else out.
0:44:25 > 0:44:31Whereas here we have an example of an enterprise which is desperate,
0:44:31 > 0:44:37curious, to turn itself into a net importer of intellectual product.
0:44:37 > 0:44:41And that's a very important lesson for the history of the sciences.
0:44:44 > 0:44:47'I was soon to see just how dramatically
0:44:47 > 0:44:50'this fuelled scientific innovation,
0:44:50 > 0:44:54'but it's worth remembering that the translation movement
0:44:54 > 0:44:57'wasn't just about science and medicine.
0:44:57 > 0:45:02'As the capital Baghdad sat in the centre of a vast successful empire,
0:45:02 > 0:45:07'it became home to an extraordinary flourishing of all kinds of culture.
0:45:17 > 0:45:22'For this is the time described by One Thousand And One Nights,
0:45:22 > 0:45:27'of great and generous caliphs, magic carpets, great journeys,
0:45:27 > 0:45:32'but also ambitious buildings, music, dance,
0:45:32 > 0:45:36- 'storytellers, and the arts.' - HE CHANTS IN ARABIC
0:45:37 > 0:45:40CHEERING AND CLAPPING
0:45:44 > 0:45:48Baghdad was such a cultured and vibrant city that one traveller
0:45:48 > 0:45:53of the time wrote, "There is none more learned than their scholars,
0:45:53 > 0:45:56"more cogent than their theologians,
0:45:56 > 0:46:01"more poetic than their poets, or more reckless than their rakes!"
0:46:08 > 0:46:11It really must have felt like Baghdad and the Arabic Empire
0:46:11 > 0:46:15were the world leaders in civilisation and culture.
0:46:15 > 0:46:21To be part of that city's growing intellectual elite must have been as exciting as it gets.
0:46:25 > 0:46:26It was a new Muslim city.
0:46:26 > 0:46:30It only started to be built in 756
0:46:30 > 0:46:37so it has that sense of being on the frontier of being new and different.
0:46:37 > 0:46:41It was full of courtiers and nouveau riche individuals
0:46:41 > 0:46:44who were trying to make their way at the Abbasid court
0:46:44 > 0:46:47and it is the sort of place
0:46:47 > 0:46:51where innovation is valued and appreciated.
0:46:53 > 0:46:57At the heart of the city's intellectual life
0:46:57 > 0:47:00was a system called the majlis.
0:47:00 > 0:47:03The word "majlis" could perhaps be best translated
0:47:03 > 0:47:04as "salon" or "talking house".
0:47:07 > 0:47:12In 9th century Baghdad what this meant was that city's ruling elite,
0:47:12 > 0:47:15the Caliph, his courtiers, the generals and the aristocracy,
0:47:15 > 0:47:17would hold regular meetings,
0:47:17 > 0:47:20you might call them seminars or discussions,
0:47:20 > 0:47:25during which the city's cleverest men, the philosophers, theologians,
0:47:25 > 0:47:27astronomers and magicians,
0:47:27 > 0:47:31would gather to discuss and debate their ideas.
0:47:31 > 0:47:34It was not the case that people were expected to adhere
0:47:34 > 0:47:38to a particular line or adopt a particular religion.
0:47:38 > 0:47:39They were allowed to express
0:47:39 > 0:47:41their own views and sentiments very freely.
0:47:41 > 0:47:45The point was that they should do so in elegant Arabic
0:47:45 > 0:47:48and with good logical reasoning.
0:47:48 > 0:47:50The effect of the majlis
0:47:50 > 0:47:54was to create a heady mix of money and brains,
0:47:54 > 0:47:57with the best minds in the empire swapping ideas
0:47:57 > 0:48:02while simultaneously engaged in fierce competition for patronage.
0:48:02 > 0:48:07'It's at this point my investigation into the first wave of Islamic science
0:48:07 > 0:48:11'returns me to the man we first met at the beginning of this story
0:48:11 > 0:48:15'in the back streets of Cairo, the great mathematician
0:48:15 > 0:48:17'who brought the West the decimal system.'
0:48:17 > 0:48:21Out of the very heart of this intellectual whirlwind
0:48:21 > 0:48:25came Al-Khwarizmi, mathematician, astronomer, courtier
0:48:25 > 0:48:28and favourite of the Caliph al-Mam'un.
0:48:28 > 0:48:33He was a product of a his age, an emigre from Eastern Persia
0:48:33 > 0:48:35into Baghdad, surrounded by books,
0:48:35 > 0:48:40well-versed in learning from Greece, Persia, India and China,
0:48:40 > 0:48:42and fearless in his thinking.
0:48:44 > 0:48:48'Al-Khwarizmi brought together two very different mathematical
0:48:48 > 0:48:53'traditions and synthesised them into something new.'
0:48:53 > 0:48:58The capacity to have on your desk simultaneously
0:48:58 > 0:49:02two very different kinds of mathematics
0:49:02 > 0:49:07presses on models of what counts as calculation,
0:49:07 > 0:49:09what counts as measurement,
0:49:09 > 0:49:13and I think accelerates the process of intellectual change.
0:49:16 > 0:49:21The first of these traditions came from the Greek-speaking world.
0:49:21 > 0:49:25Greek mathematics dealt mainly with geometry,
0:49:25 > 0:49:30the science of shapes like triangles, circles and polygons,
0:49:30 > 0:49:33and how to calculate area and volume.
0:49:33 > 0:49:36The other great mathematical tradition
0:49:36 > 0:49:39Al-Khwarizmi inherited came from India.
0:49:39 > 0:49:43They'd invented the ten-symbol decimal system
0:49:43 > 0:49:46which made calculating much simpler.
0:49:46 > 0:49:48Thanks to the translation movement,
0:49:48 > 0:49:52Al-Khwarizmi was in the astonishingly lucky position
0:49:52 > 0:49:58of having access to both Greek and Indian mathematical traditions.
0:49:58 > 0:50:01He combined geometrical intuition
0:50:01 > 0:50:03with arithmetic precision,
0:50:03 > 0:50:06Greek pictures and Indian symbols,
0:50:06 > 0:50:12inspiring a new form of mathematical thinking that today we call algebra.
0:50:16 > 0:50:21'As a physicist, I've spent much my life doing algebra
0:50:21 > 0:50:25'and I can't overstate its importance in science.
0:50:25 > 0:50:27'But it is a strange idea.
0:50:27 > 0:50:31'I remember being perplexed when my maths teacher first started talking
0:50:31 > 0:50:36'about mathematics not using numbers but with symbols like x and y.
0:50:39 > 0:50:42'It's an incredibly liberating idea,
0:50:42 > 0:50:46'because it allows you to solve problems without getting bogged down
0:50:46 > 0:50:49'in messy numerical calculations.'
0:50:49 > 0:50:53So we have here this priceless manuscript,
0:50:53 > 0:50:56- HE READS ARABIC - Al-Khwarizmi's book.
0:50:56 > 0:51:00'Professor Ian Stewart has studied algebra
0:51:00 > 0:51:02'for much of his working life.
0:51:02 > 0:51:05'Together we looked at an early copy of the book
0:51:05 > 0:51:08'in which the idea really took form.'
0:51:08 > 0:51:12I see here, although it's written in the margins, the title of the book.
0:51:12 > 0:51:18Al-Jabr w'al-Muqabala, so that's the first time the word Al-Jabr appears.
0:51:18 > 0:51:21- Algebra.- That's where our world algebra comes from.
0:51:21 > 0:51:25Now, what I found very early on is that he said,
0:51:25 > 0:51:29"I discovered that people require three kinds of numbers,"
0:51:29 > 0:51:33- HE READS ARABIC - So, roots, squares and numbers.
0:51:33 > 0:51:36So, what is he trying to do here?
0:51:36 > 0:51:38This is what we would now call x and x squared.
0:51:38 > 0:51:40This is quadratic equations.
0:51:40 > 0:51:42This really is algebra.
0:51:42 > 0:51:44So, he's setting you up for a book
0:51:44 > 0:51:47about how to solve equations by algebraic methods.
0:51:47 > 0:51:51Now, quadratic equations, I thought were around and being solved
0:51:51 > 0:51:54long before Al-Khwarizmi back in Babylonian times.
0:51:54 > 0:51:57So what's the big deal about this book?
0:51:57 > 0:51:59It's the point of view.
0:51:59 > 0:52:04He treats root and square as if they were objects in their own right.
0:52:04 > 0:52:06They're not just some number
0:52:06 > 0:52:09that we are trying to find out,
0:52:09 > 0:52:11they are a process you apply.
0:52:11 > 0:52:14What Al-Khwarizmi is thinking of
0:52:14 > 0:52:18is square means take the root and multiply it by itself.
0:52:18 > 0:52:21And that recipe is true, whatever the root might be.
0:52:21 > 0:52:23If it's five, it's five times five, it's 25.
0:52:23 > 0:52:25If it's three, it's three times three.
0:52:25 > 0:52:29He's giving you a general recipe, now called an algorithm.
0:52:29 > 0:52:31After him.
0:52:31 > 0:52:34R...r...right, algorithm comes from...
0:52:34 > 0:52:36Its another world that comes from Al-Khwarizmi.
0:52:36 > 0:52:40Now, he talks about this procedure on the next page.
0:52:40 > 0:52:44You take the number multiplying the root and then you halve it,
0:52:44 > 0:52:46and then you multiply it by itself
0:52:46 > 0:52:50Then you add it to the other number and take the square root. That's the algorithm, is it?
0:52:50 > 0:52:54That's right and this is where you see the difference,
0:52:54 > 0:52:57because previous writers on the subject
0:52:57 > 0:52:59would have said things like,
0:52:59 > 0:53:03"Take half of 10, which is 5, square that, which is 25."
0:53:03 > 0:53:06And then they'd do another problem,
0:53:06 > 0:53:09take half of 12, which is 6, and square that, which is 36.
0:53:09 > 0:53:13And they'd run you through the same process over and over again with different numbers.
0:53:13 > 0:53:17And it would be up to you to infer how to do it on the next problem.
0:53:17 > 0:53:19- But he doesn't do that. - He doesn't do that.
0:53:19 > 0:53:21He says, "Take half the root,
0:53:21 > 0:53:23"whatever the root is, take half the root."
0:53:23 > 0:53:25So half the root is an object.
0:53:25 > 0:53:28If the root is an object, so is half the root.
0:53:28 > 0:53:31So you don't have to have in your mind what that root stands for.
0:53:31 > 0:53:33You can forget about what it stands for.
0:53:33 > 0:53:38When you come to square it, you just know to square the thing, I don't care what the thing is.
0:53:38 > 0:53:44So, you abandon temporarily this link with specific numbers,
0:53:44 > 0:53:49manipulate the new objects according to the rules his book is explaining.
0:53:49 > 0:53:53And then the numbers that these objects are represent
0:53:53 > 0:53:57in your particular problem will miraculously appear at the end
0:53:57 > 0:54:00and you'll end up with x = 3 or whatever it is.
0:54:00 > 0:54:04So, how revolutionary do you regard Al-Khwarizmi's work?
0:54:04 > 0:54:11He made it possible for algebra to exist as a subject in its own right,
0:54:11 > 0:54:13rather than as a technique for finding numbers.
0:54:13 > 0:54:19The least interesting bit of an algebraic calculation is when you get to the end and discover that x = 3.
0:54:19 > 0:54:22It's the route you take to get there.
0:54:22 > 0:54:25But if it was a special route and a different route for each problem,
0:54:25 > 0:54:28that wouldn't be interesting either, it would just be a big mess.
0:54:28 > 0:54:32There's a beautiful general series of principles,
0:54:32 > 0:54:36and if you understand those, then you understand algebra.
0:54:58 > 0:55:02What is the true global importance of algebra?
0:55:02 > 0:55:05It's been used throughout the ages to solve all sorts of problems.
0:55:05 > 0:55:10Let the mass of a cannon ball be 'm', let the distance it has to travel be 'd'.
0:55:10 > 0:55:13You use algebra to work out the optimum angle
0:55:13 > 0:55:16you have to point your cannon.
0:55:16 > 0:55:18That sort of knowledge wins wars.
0:55:19 > 0:55:22'Or let's call the speed of light 'c',
0:55:22 > 0:55:25'the change in the mass of an atomic nucleus 'm',
0:55:25 > 0:55:29'and then calculate the energy released
0:55:29 > 0:55:33'with the following algebraic formula, E=mc2.
0:55:35 > 0:55:39'Mastery of that information truly is power.
0:55:51 > 0:55:54'Algebra has helped create the modern world.
0:55:54 > 0:55:58'Our science is unimaginable without it.
0:55:58 > 0:56:01'It sums up so much that was remarkable
0:56:01 > 0:56:03'about medieval Islamic science,
0:56:03 > 0:56:09'taking ideas from Greece and India, combining and enhancing them.
0:56:09 > 0:56:12'Similarly, modern medicine owes a considerable debt
0:56:12 > 0:56:15'to the work of the Islamic physicians.
0:56:15 > 0:56:19'But I think the real story of what happened to science
0:56:19 > 0:56:22'in the Islamic world in 8th and 9th centuries
0:56:22 > 0:56:25'tells us more than any single discovery.
0:56:25 > 0:56:27'What it really tells us
0:56:27 > 0:56:31'is about the universal truth of science itself.'
0:56:34 > 0:56:37I believe that the first great achievement
0:56:37 > 0:56:40of the medieval Islamic scientists was to prove
0:56:40 > 0:56:44that science isn't Islamic, or Hindu or Hellenistic,
0:56:44 > 0:56:46or Jewish, Buddhist or Christian.
0:56:46 > 0:56:50It cannot be claimed by any one culture.
0:56:50 > 0:56:53Before Islam, science was spread across the world.
0:56:53 > 0:56:55But the scholars of medieval Islam
0:56:55 > 0:56:58pieced together this giant scientific jigsaw,
0:56:58 > 0:57:00by absorbing knowledge
0:57:00 > 0:57:04that had originated from far beyond their own empire's borders.
0:57:04 > 0:57:07This great synthesis produced not just new science,
0:57:07 > 0:57:09but showed for the first time
0:57:09 > 0:57:11that science as an enterprise
0:57:11 > 0:57:16transcends political borders and religious affiliations.
0:57:16 > 0:57:20It's a body of knowledge that benefits all humans.
0:57:20 > 0:57:24That's an idea that's as relevant and as inspiring as ever.
0:57:39 > 0:57:43'In the next episode, I investigate how one of the most important ideas
0:57:43 > 0:57:46'in the world arose in the Islamic empire.
0:57:46 > 0:57:51'I discover how mathematics and experimentation fused together
0:57:51 > 0:57:55'as the empire embraced a medieval industrial revolution.
0:57:55 > 0:58:00'And in Cairo, I find out how these ideas
0:58:00 > 0:58:04'led directly to today's world of science and technology.'
0:58:22 > 0:58:25Subtitles by Red Bee Media Ltd
0:58:25 > 0:58:28E-mail subtitling@bbc.co.uk