Transcript for:
Islamic Contributions to Science Overview

[Music] my name is Jim alkal and I'm a professor of physics at the University of su studying the innermost secrets of atoms and their nuclei has been at the heart of my working life but there's another side to me [Music] I was born and grew up in Baghdad to an English mother and Iraqi father but left Iraq with my family in the late '70s when Saddam Hussein came to Power by then science was already my great passion in life and as I studied it further I saw myself fully par of the western tradition inspired by names like Newton and Einstein but buried away was this nagging feeling that I was ignoring part of my own scientific Heritage I still remembered my school days in Iraq and being taught of a golden age of Islamic scholarship there between the 9th and 12th centuries a great leap in scient scientific knowledge took place in Baghdad Damascus Cairo and Cordo so I want to unearth this buried history to discover its great figures and to assess exactly what their contribution to science really was are there medieval Muslim scientists who should be spoken of in the same breath as Galileo or Newton or Einstein and crucially what is the relationship between science and Islam [Music] [Applause] [Music] my journey into the science of the medieval Islamic world will take me through Syria Iran and North Africa I started in the back streets of the Egyptian Capital Cairo with the realization that the language of modern science still has many references to its Arabic Roots take scientific terms like algebra algorithm alali I instantly recognize these words as Arabic and and these are at the very heart of what science does there will be no modern mathematics or physics without algebra no computers without algorithms and no chemistry without alkalis surprisingly few people in the west today even scientists are aware of this medieval Islamic Legacy but it wasn't always so from the 12th to the 17th century European scholars regularly refer to earlier Islamic texts I have here copies of some pages uh of the book liberachi by the great Italian mathematician Leonardo Pizano otherwise known as Fibonacci what's fascinating is that on page 46 is a reference to an older text called modem algebra El mukabala and in the margin is the name Ma which is the latinized version of the Arabic name Muhammad the person he's referring to is Muhammad IB mus alari in fact Arabic names crop up in many medieval European texts on subjects as varied as mapmaking Optics and Medicine but I want to start with elawar ismi because his work touches on a crucial aspect of all our lives today it's thanks to elisi that the European World realized that their way of doing arithmetic which was still essentially based on Roman numerals was hopelessly inefficient and downright clunky if I ask you to multiply 100 23 by 11 you may even be able to do it in your head the answer is 1353 but try doing it with Roman numerals you'd have to multiply cxx I I I by XI it can be done but trust me it's not fun ismi showed Europeans that there's a better way of doing arithmetic in his book entitled it the Hindu art of Reckoning he describes a revolutionary idea you can represent any number you like with just 10 simple symbols the idea of using just 10 symbols the digits from 1 to 9 plus a symbol for zero to represent all numbers from one to Infinity was first developed by Indian mathematicians around the 6th Century ad and I can't overstate its importance let me show you here are the numbers in Indian Arabic numerals and here are the numbers we're more familiar with in the west 1 2 3 4 5 6 7 eight nine and you can see the similarity between these numbers in particular for instance the digits two and three if I tip this sideways you can see now how they look like numbers two and three and what's powerful about these digits this numerical system is how it simplified arithmetic calculations but elisi and his colleagues went further than just translating the Indian system into Arabic they created the decimal point this text written a century afteri is by a man we know only as Al here he shows it this same decimal system can be extended to describe not just whole numbers but fractions as well the Infinity of possibilities that lie in between the integers here's a copy of El's manuscript where he showed how the decimal point is used for the very first time he describes it by using a dash here are the digits 1 7 7 968 and you can see there's a small Dash over the nine indicating the decimal place the idea of the decimal point is so familiar to us that it's hard to understand how people managed without it but like all great science it's blindingly obvious after it's been discovered [Music] story of numbers and the decimal point hints that even over a thousand years ago science was becoming much more Global ideas were spreading emerging out of India Greece even China and cross fertilizing and looking on a map that shows where people lived a thousand years ago gave me my first insight into why medieval Islam would play such an important role in the development of science now look at which city lies at the center of the Known World a place where the widest range of peoples and ideas were bound to collide it's the city where I was born the capital of the Islamic empire Baghdad recent events mean I can no longer visit the city but these are the home movies of my cousin Faris filmed in the 1960s the Baghdad we knew then looked nothing like the bomb wrecked City it is now I certainly grew up proud to be associated with one of the world's greatest cities Baghdad was founded in 762 ad by the caleff El Mansour his aim was to make it the Glorious capital of a brand new Empire United by Islam the rising religion of the time the Abbasid cffs had claimed their right to rule by declaring that they were directly related to The Prophet Muhammad who had founded the new religion over a hundred years earlier but in that short time the armies of Islam had conquered a vast territory St in a small area around Medina they moved rapidly out of the Arabian Peninsula and within a few decades had taken control of the Levant North Africa Spain and Persia I think one must bear in mind that this is an era in which people actually believed in God and the dramatic successes of the Arabs as they poured out of Arabia uh was such that a lot of people did sort of observe and say they must have God on their side this must be the truth true God some people did convert or if they didn't convert they did submit to Arab Muslim political control for that reason by the early 8th Century Islamic cffs ruled a vast territory and like most successful Emperors from Caesar to Napoleon they understood that political power and scientific knowhow go hand in hand there were many reasons for this some were practical medical knowledge could save lives military technology could win Wars mathematics could help deal with the increasing complexities of the finances of state and Islam as a religion also played a pivotal role the prophet himself had told Believers to seek knowledge wherever they could find it even if they had to go as far as China and many Muslims I'm sure felt that to study and better understand God's creation was in itself a religious duty but there were also other less edifying motives at play to many in the ruling Elite of the Islamic empire knowledge itself had a self-serving purpose because possessing it was seen as proof of the new Empire's superiority over the rest of the world but with military EMP political success the Islamic cffs faced an inevitable problem how do you sensibly govern a hugely diverse population although some of the Empire had converted to Islam they were still separated by huge distances and adhered to many different traditions and languages in the 8th Century ad the Empire's leader the caleff Abdul mik had to find a way of administering this mish mash of languages like all the great figures of the Islamic empire Abdul mik lived in a culture without portraiture all we have are later impressions of what he might have looked like his solution was Sweeping in scale and inadvertently laid the foundations of a scientific Renaissance it was this Abdul Malik Maran who said this bureaucratic chaos has to stop we cannot continue to run a government and govern all of this span of land with this uh uh Tower of Babel languages so he wanted to govern it with a uniform language that uniform language of course he wanted to be able to understand it so he demanded that it be in Arabic but the choice of Arabic as the common language of the empire went beyond administrative convenience the decision had extra force and persuasiveness because Islam's holy book the Quran is in Arabic and Muslims therefore consider Arabic to be the language of [Music] God the words of the Quran are so sacred that its text hasn't changed in over 1,400 years by comparison English has changed dramatically in just 700 years to our ears cha is almost unintelligible whereas any Quran can be understood by Anyone who reads Arabic making copies of the Quran has always been a specialized and highly respected job since the foundation of Islam calligraphy expert naif scaf who lives in the Syrian Capital Damascus writes for mosques and IM medras all over the country these are words he's found himself writing over and over again words of great significance for Muslims they're the opening line to each chapter in the Quran so it what it says is which means in the name of God the most gracious and the most merciful so he saying the complexity of Arabic calligraphy was enforced on them because of the spread of Islam because they were worried that the meaning of the words in the Quran will be lost uh if it was read by people who don't speak Arabic then they wouldn't Not only would they misinterpret it they just wouldn't be able to distinguish between different letters so not only did they add dots on certain letters they also added other little squiggly lines which changed the sound of vowels and it was something that they put in place just to ensure that people were able to have the right pronunciation when they read the Quran the consequences for science were immediate Scholars from different lands who previously had no way of communicating now had a Common Language and it was a language that was specially developed to be precise and unambiguous which made it ideal for scientific and Technical terms what this meant was the summoning into existence of a vast intellectual Community where Scholars from very different parts of the world could engage in dialogue comparison debate argument often very Fierce argument with each other it was possible for Scholars based in Corda in southern Spain to engage in literary and scientific debate with Scholars from Baghdad or from uh sarand but I can tell you that Scholars aren't motivated by the love of knowledge alone there's nothing like a large hunk of cash to focus the Mind by the early 800s the ruling Elite of the Islamic empire were pouring money into a truly ambitious project which was Global in scale and which was to have a profound impact on science it was to scour the libraries of the world for scientific and philosophical manuscripts in any language Greek syak Persian and Sanskrit bring them to the Empire and translate them into Arabic this became known as the translation [Music] movement the effort Scholars put into finding ancient texts was astonishing and one key reason for this is that bringing a book to the cff which you could add to his Library could be extremely lucrative The Story Goes that the khif aloon was was so obsessed that he would send his Messengers out of Baghdad far and wide to distant lands just to get hold of books that he didn't possess for the translation movement and anyone who brought him back a book that he didn't have he'd repay him its weight in gold to give some sense of the extent of this activity sort of between seven 50 and 950 um somebody called aadim who wrote a list of sort of the intelligencia of the aasted era lists 70 translators so it was quite a large cohort of people involved in translation and obviously he only named the well-known they could get up to 500 gold dinar a month which is probably around $24,000 which is a huge sum of money for what they were doing it was a very very prestigious well-paid well patronized activity and motivating This Global acquisition of knowledge was a pressing practical concern one that rarely crosses our minds today this is the new library at Alexandria in Egypt but fresh in the memory of many in the empire was the story of the destruction of the original library at Alexandria centuries earlier and the shocking loss of thousands of years of accumulated knowledge one of the things that we tend to forget because we live in an age of massive information storage and perfect communication more or less um is the everpresent possibility of total loss that was very very important for medieval Islamic scholars they knew extremely well that writings could be forgotten or buried or burnt or destroyed that cities could pass away and what we see in Baghdad or Cairo or sarand is exactly the Gathering Together translation analysis accumulation storage and preservation of material that they were well aware could be entirely lost forever [Applause] [Music] [Applause] and if there was one branch of knowledge that everyone from the Mighty kff To The Humble Trader wanted to preserve and enhance it was medicine these were after all times when few lived to old age writings from the time remind us that what we might consider a relatively minor infection today could be a death sentence religious teachings then were not just a source of comfort there were a constant reminder that we should never give up in the Hadith which is the collected sayings of the Prophet Muhammad it says which means that God did not send down a disease without also sending down its cure it statements like this that lead Muslims even today to believe that cures for all diseases are out there somewhere and that we need to search to find them to assess how this optimism actually affected Islamic medicine I met up with Dr Peter pman in the Syrian Capital Damascus he's a leading expert on Islamic medicine who spends much of his time researching here in the Middle East what people don't realize is that uh the history of Islamic medicine is really the history of our medicine because our medicine the university medicine be used until the 19th century it was based to a large extent on all these work of these Islamic Physicians Islamic medicine built extensively on the foundations laid by the ancient Greeks the most highly prized and among the first to be translated into Arabic with the medical manuscripts of the 3 Century Greek physician galin galin believed that a healthy body was one in balance a balance of four types of fluids called humors which circulate through the body and any one of which if out of balance would cause illness and a change of temperament the four humors were yellow bile which if in excess would cause the patient to become bilious or bad tempered and nauseous blood too much of which would cause the patient to become sanguin or cheerful and flushed black bile which nxs would cause the patient to become lethargic melancholic even depressed and FL M which in excess would cause the patient to become fmatic or apathetic and emotionally detached Galen argued that illnesses are caused by an imbalance in one of the humors and so the Cure lies in draining the body of some of that humor and so he recommended techniques like cutting to induce bleeding or using emetics to induce vomiting but Islamic doctors were acutely aware that galin and Greek medicine were only one source of medical [Music] knowledge there were other traditions of medicine that they were equally Keen to incorporate into their understanding of how the body functioned medieval Arabic texts refer to Wise Women folk healers Who provided medical drugs this tradition continues today as I found when I came across one for myself in the back streets of hamamat in Tunisia this is Arafat nail she's been running her shop selling medicinal herbs and spices for over 20 years she believes that her remedies can cure a wide range of medical ailments ah okay well in the back streets of Tunisia this knowledge is still being used but medieval Islamic doctors were also aware of other traditions of medicine from China and India and yet another tradition of medical guidance Came From Within Islam itself and takes some of its ideas from the Quran and some from the collected sayings of the Prophet the Hadith in a book shop in monasa in Tunisia I found a copy of a very popular book available right across the Islamic world this book is called The Prophet's medicine and uh it see how old it is the author was born between 691 and 751 H which places him in the 14th century here's an interesting bit uh where it deals with the plague it says if you come across a land where the plague has come down then do not enter that land and if the plague comes down onto your land and you're you are there then do not leave your homes in the hope of escaping it so sort of makes a lot of sense but here's quite an amusing part um it deals with epilepsy uh and it says that the Greeks or or galin believed that epilepsy originated in the brain so however they were ignorant they didn't realize the true cause of epilepsy which is the the possession of the body by evil spirits and it talks about the cure for epilepsy being exorcism hardly scientific but Islam's most tangible contribution to medicine is less in its specific remedies and More in its overarching [Music] philosophy it is after all a religion whose central idea is that we should feel compassion for our fellow humans and accompanied by Dr Peter pman I'm going to see a physical bricks and mortar manifestation of medieval Islamic compassion this is the naline hospital the leading Hospital of the Islamic empire built here in Damascus and now a museum this was built in the 1150s 1154 I believe one of the ideas which are stipulated in uh in Islam is the idea to be charitable and charity yes exactly and it's an obligation to to give arms and stuff like that and so if you're a ruler or if you have a lot of money what you could do is obviously you could really be charitable charitable and set up like a nice Hospital like this one and within the hospital Islam actively encouraged a high degree of religious tolerance something we take for granted in modern secular society the hospital was open to all communities so you would have Christians you would have Jews Muslims obviously Maybe other denominations both as patients and also as practitioners like a Christian Studies with the Muslim Muslim says my best student was a Jew and so the medicine which was practiced here transcended religion I mean typically how many Physicians would there be well it depends well like for certain hospitals we hear figures of like 24 or 28 Physicians yes the Physicians would do the rounds in the morning to sit do their prescriptions and stuff like that hasn't changed over the ages yeah as a result of the translation movement those Physicians now became aware of the latest remedies from as far away as India and China and as the new drugs filtered in from the rest of the world hospitals started to set up a new kind of facility within their walls the pharmacy so this notion of a pharmacy in a hospital is that a new innovation the whole package certainly that's uh that's new and what is interesting if you look for Innovation you like on the level of Pharmacy if you look at Baghdad or even Damascus it's at this Crossroad of cultures so Nots of new things come in like mask for instance my robal and you have like Indian drugs there's like an Indian pill for instance which is good against headaches and you like a bad breath but also you know gives you sexual appetite and stuff like that so you know kills a headache gives you um fresh breath fresh breath and and gives you increase and so so it's like toothpaste Viagra and aspirin that's right all in one fantastic so well let's uh walk in here Peter wants to show me perhaps the most ghoulish aspect of Islamic medicine surgery here you have like a wonderful illustration this it appears that this is the the first anatomical illustration in history you like you see it says adala which is which means muscle and so these are like the different muscles which move the eyelids so it was understood then that the muscles controlled the oh absolutely the lens in your eye yeah and move the eyelid and stuff like that so the other thing which which we have here which is really nice is I think we have some uh you know like opthalmological instruments for instance it's a hook could be used for instance you like to kind of pull back your eyelid that sort of thing you know I mean these instruments were very useful to the doctor although these tools might look crude eye surgery was one of Islamic medicine's great successes one Innovation was to improve an older technique for curing cataracts called couching which in their hands had a success rate of over 60% in a living subject the corne would be clear and you'd be able to see the pupil clearly with the catara sitting behind the pupil the the wiac to see how couching stands the test of time I'm meeting up with eye surgeon Mr Vic sh right cataract is the lens inside the eye which sits behind the pupil um as with time with age the Cataract the lens gets cloudier and cloudier and that's what it's referred to as a cataract um I've brought along a replica of a medieval couching knife and a description of the treatment by alassis which is the Latin name for the great 10th Century Islamic surgeon El zahi uh he says you take the couching needle in your right hand if it be the left eye and so on and then thrust the needle firmly in at the same time rotating it with your hand until it penetrates the white of the eye and you feel the needle has reached something empty uh so he's talking about how to dislodge exactly so I mean maybe you can show me we've got some eyes here y I'll certainly give it a shot and what they would have done would have attempted to go in just by the white of the eye just at the edge where the corer is and then what they are attempting to do is to sweep around trying to break all those ligaments of that lens and trying to get the lens to drop away from the pupil to allow more light to enter in through the people and to brighten the subject's vision but of course you haven't got the capacity to focus oh yeah you haven't got a lens nowly so that was a big problem until people started compensating that with specs later on right right what is your feeling about how advanced and successful well they were on the you know the general ballpark they were at the right place they were they were trying to remove the Cataract away from the visual axis they understood the anatomy of the eye they had some understanding of the anatomy of the eye and you know that the lens was behind the pupil and that's what was causing the um visual loss and so removing that um you know and that General principle is still the same right and you know there are still accounts of it being used in certain parts of the world [Music] presently looking back at Medieval Islamic with modern scientific eyes is frustrating they take us true many things we know to be nonsense but on the other hand their desire to deal with this vast subject logically and systematically is admirable and truly marks a break with the past one Islamic scholar more than any other embodies the synthesis of religion faith and reason his name was ibben Cena or avyna as he's known in the west he was a polymath who clearly thrived in intellectual and courtly circles in 1025 he completed this Al or the cannon of medicine in it ibben Cena collated and expanded on all that had gone before him medical ideas from Greece to India and turn them into a single work so how would you place this SP book in a historical context oh it's hugely important I mean it's uh I mean there are a few books which are as important as the Canon because what this encyclopedia does it kind of you know sweeps away everything else it becomes a text book it be it supersedes a lot of other texts and people even complain that like it's so good it's so tightly organized it's so easily accessible that uh you know like people forget to read the the Greek sources in Arabic translation this whole first book this is the first book contains what we call the Kad the general principles so it's all about how the human body works you know how disas work in general the second book contains the diseases what we sometimes call from tip to toe like from tip to toe so he starts with the diseases of the head and then he moves moves down like the eyes the ears the nose the mouth and he he normally they end up at the sexual organs you see at First Sight the sheer ambition of the three volumes is hugely impressive here's an attempt at diagnosis and cure for diseases as diverse as depression meningitis and small poox and there's even detailed chapters on more common problems so um like for instance here you have like headaches so different kinds of headach so headaches caused by Pleasant fragrant smells or and then he's also got um so um hangovers different kind you can get headache from sex is that right well I mean I hasn't happened to me yet but I mean you know let's see so the treatment of headache caused by sex so if somebody uh has or is befallen by suffers from a headache after sex and he also has a repletion so he like he has too many superfluities or something like that um so one has to First Resort to Venice section or blood letting and then you should use purging in for each both of them I mean like blood letting and purging are necessary a lot of the the stuff in here sounds like nonsense of course because this is not modern medicine no it's not um so how long was was this taken seriously well the fundamental ideas contained here about how the body works I mean they hadn't changed until the early 19th century I mean there was there were there was progress obviously on certain levels but the feel like the essence was the same and then came the big break with the discovery of bacteria and and viruses and things like that and from the second half of the 19th century onward you know medicine was totally revolutionized that's right IB Cena's Cannon of medicine is a landmark in the history of the subject although much of the Medical Science it espouses we know now to be terribly misguided its value lies in accumulating the best knowledge in the world at the time into one accessible organized text the cannon would give future Generations something to [Music] rewrite cataloging the world's medical knowledge has clear and obvious benefits but the Islamic Empire's Obsession to uncover the knowledge of the Ancients went beyond practical matters like medicine many like the cff elmon believed that the people of antiquity possessed dark even magical powers and what's more new evidence is coming to light to show just how hard Islamic scientists worked to ReDiscover [Music] them to find out about that story I have to visit the harsh burnt yellow of the Sahara desert in Egypt there I am to meet an academic who wants to show me how the translation movement took the Arabs to Egypt on a quest to break a code which they thought hid the secret of the Dark Art of alchemy [Music] this is Sakara a necropolis or graveyard of the ancient pharaohs over a 10 Acre Site it's a collection of burial Chambers and step pyramids that were built in the third millennium before Christ these are said to be among the oldest Stone buildings in the world mind the step here archaeologist Dr okasha alali is my guide he was about to reveal the most astonishing story of my journey so far look at that like most people I believe that Egyptian hieroglyphs had remained completely undeciphered until the 19th century then came the chance discovery of the famous Rosetta Stone this Stone had the same inscription written in both hieroglyphs and Greek it provided the crucial Clues which British and French Scholars used to decipher the writings of ancient Egypt that's the usual Story one hears but Dr alali has made a discovery that dramatically Alters it he has recently Unearthed a number of rare works by the Islamic scholar ibben wah what he did was figure out a correspondence between hieroglyphs like these and letters in the Arabic alphabet if look here for example at's manuscript you see he's giving us the Egyptian hieroglyphic signs that have underneath yes and they have the fanatic value in Arabic underneath so look very carefully at this one he says seen underneath that seat yes now look at this seat here that is s that seat in Egyptian hieroglyphic is used for the sign s scene which is what you see here SE that is the name of the god Osiris Osiris oh with an S that's a scene yeah this is the letter H this one here this is the H the water wave right is a letter N or n in Arabic T and the letter F these are all letters these are all letters but then he realized but how did he decipher the hieroglyphs the one good thing about the early Arabic Scholars was their ability to link ancient Egyptian language we call heroglyph to link it with their own contemporary Coptic they realized that Coptic is nothing but the later stage of ancient Egyptian language and they realized this because the translation movement had literally placed hundreds of Coptic texts into their hands the scholars could now see a direct link between hieroglyphs and Arabic what fraction of these symbols would have been correctly deciphered they got about 14 letters they CRA more than half of the Egyptian hieroglyphic correctly so that was a remarkable achievement for people were on the 9th century 10th Century well that's probably the biggest Revelation for me so far on on my travels that uh egyptology didn't begin in the 19th century yet again it seems that Islamic scholars actually cracked hieroglyphics and they cracked it for for strange reasons they cracked it because they were interested in in astrology and and Alchemy but here is another example of this amazing translation movement they weren't just translating Greek and and and Indian and Persian text they were translating Egyptian hieroglyphics as well absolutely incredible unfortunately for the cff El mmon the hieroglyphs contained no alchemical secrets but what this story reveals to me is the insatiable curiosity Islamic scholars had about the world they were desperate to absorb Knowledge from all cultures purely on merit with no quals about the places or religions from which it came most intellectual Traditions including if I may say so our own tend to work very hard to keep everybody else out whereas here we have an example of an Enterprise which is desperate curious to turn itself into a net importer of intellectual product that's a very important lesson for the history of the Sciences I was soon to see just how dramatically this fueled scientific innovation but it's worth remembering that the translation movement wasn't just about science and medicine as the capital Baghdad sat in the center of a vast successful Empire it became home to an extraordinary flourishing of all kinds of [Music] culture for this is the time described by 101 Knights of great and generous cffs magic carpets great Journeys but also ambitious buildings music dance storytellers and the [Applause] Arts Baghdad was such a cultured and vibrant City that one traveler of the time wrote there is none more learned than their Scholars more cogent than their theologians more poetic than their poets or more Reckless than their [Music] rakes it really must have felt like Baghdad and the Arabic empire were the world leaders in Civilization and culture to be part of that City's growing intellectual Elite must have been as exciting as it gets it was a new Muslim City it only started to be built in 756 so it has that sort of sense of almost being on on a frontier of being something new of being something different um it was full of coures it was full of um sort of nvo individuals who were trying to make their way at the aasted court and it is the sort of a place if you like where Innovation is valued and appreciated at the heart of the city's intellectual life was a system called the Magus now the word Magus could probably best be translated as Salon or talking house in 9th century Baghdad what this meant was that the city's Elite the califf his courters generals and the aristocracy would hold regular meetings you might call them seminars or discussions during which the city's cleverest men the philosophers theologians astronomers and logicians would gather to discuss and debate their ideas it was not the case that people were expected to adhere to a particular line or adopt a particular religion they were allowed to express their own sentiments and their own views very freely the point was that they should do so in elegant Arabic and a good logical reasoning the effect of the Magus was to create a hey mix of money and brains with the best Minds in the Empire swapping ideas while simultaneously engaged in Fierce competition for patronage it's at this point my investigation into the first wave of Islamic science returns me to the man we first met at the beginning of this story in the back streets of Cairo the great mathematician who brought the West the decimal system out of the very heart of this intellectual Whirlwind came alisi mathematician astronomer courtier and favorite of the kff El mmon he was a product of his age an immigrate from Eastern Persia into Baghdad surrounded by books well-versed in learning from Greece Persia India and China and fearless in his thinking alisi brought together two very different mathematical traditions and synthesized them into something new the capacity to have on your desk simil aneous two very different kinds of mathematics presses on models of what counts as calculation what counts his measurement and I think accelerates the process of intellectual change the first of these Traditions came from the greeke speaking World Greek mathematics dealt mainly with geometry the science of shapes like triangle angles circles and polygons and how to calculate area and volume the other great mathematical tradition alisi inherited came from India they' invented the 10 symbol decimal system which made calculating much simpler thanks to the translation movement alar ismi was in the astonishingly lucky position of having access to both Greek and Indian mathematical traditions he was able to combine geometrical intuition with arithmetic Precision Greek pictures and Indian symbols inspiring a new form of mathematical thinking that today we call algebra as a physicist I've spent much of my life doing algebra and I can't overstate its importance in science but it is a strange idea I remember being perplexed when my math teacher first started talking about mathematics not using numbers but with symbols like X and Y it's an incredibly liberating idea because it allows you to solve problems without getting bogged down in messy numerical calculations so we have here this Priceless manuscript kab Alaris alar ism's book and professor Ian Stewart has studied algebra for much of his working life together we looked at an early copy of the book in which the idea really took form published I see here although it's written sort of in the margin the title of the book uh Al jabber M so that's the first time the word algebra appears algebra algebra that's where our word algebra comes from now what I found very early on is that he said I I I discovered that people require three kinds of numbers umud so Roots squares and numbers so what is it trying to do here this is what we would Now call x and x squ this is quadratic equations this really is algebra so he's setting you up for a book about how to solve equations by algebraic methods okay now quadratic equations I thought were around and being solved long before Caris me back to Babylonian time so you know what's the big deal about this book it's the point of view he treats root and square as if they're objects in their own right they're not just something some number that we're trying to find out they're a process you apply what Al charism is thinking of is square means take the root and multiply by itself and that recipe is true whatever the root might be if it's five it's 5 Time 5 it's 25 if it's three it's 3 * three um he's giving you a general recipe now called an algorithm after him right the algorithm comes from it comes from it's another word that comes from Alaris yes now he talks about this procedure here on the next page um you you take the number multiplying the root and then you Harve it and then you multiply it by itself then you add add it to the other number and take the square root that's that's the algorithm is it that's right and this is where you see the difference because previous writers on the subject would have said things like take half of 10 which is five square that which is 25 and then they do another problem take half of 12 which is six square that which is 36 and they'd run you through this same process over and over again with different numbers and it would be up to you to infer how to do it on the next problem but he doesn't do that he doesn't do that he says take half the root whatever the root is take half the root so half the root is actually an object if the root is an object half the roote is an object so you don't have to have in your mind what that route stands for you you can forget about what it stands for when you come to square it you just know okay I should Square this thing I don't care what the thing is so you abandon temporarily this link with specific numbers manipulate the new objects according to the rules that his book is explaining and then the numbers that these objects represent in your particular problem will miraculously appear at the end and you'll end up with x equals 3 or whatever it is how revolutionary do you regard Alaris his work he made it possible for algebra to exist as a subject in its own right rather than as a technique for finding numbers the least interesting bit of an algebraic calculation is when you get to the end and discover that x equals 3 it's the route you take to get there but if it was a special route for each problem and a different route for each problem that wouldn't be interesting either it would just be a big mess there's this beautiful General series of principles and if you understand those then you really understand algebra [Music] [Applause] what is the true Global importance of algebra it's been used throughout the ages to solve all sorts of problems let the mass of the Cannonball be M let the distance it has to travel be D use algebra to work out the optimum angle you have to point your cannon that sort of knowledge wins Wars or let's call the speed of light C the change in mass of an atomic nucleus M and then calculate the energy released with the following algebraic Formula E = M c² Mastery of that information truly is power algebra has helped create the modern world our science is unimaginable without it it it sums up so much that was remarkable about medieval Islamic science taking ideas from Greece and India combining and enhancing them similarly modern medicine owes a considerable debt to the work of the Islamic Physicians but I think the real story of what happened to science in the Islamic world in the eth and 9th centuries tells us more than any single Discovery what it really tells us is is about the universal truth of science itself I believe that the first great achievement of the medieval Islamic scientists was to prove that science isn't Islamic or Hindu or helenistic or Jewish Buddhist or Christian it cannot be claimed by any one culture before Islam science was spread across the world but the scholars of medieval Islam pieced together this giant scientific jigsaw by absorbing knowledge that had originated from far beyond their own Empire's borders this great synthesis produced not just new science but showed for the first time that science as an Enterprise transcends political borders and religious affiliations it's a body of knowledge that benefits All Humans now that's an idea that's as relevant and as inspiring as ever [Music] in the next episode I investigate how one of the most important ideas in the world arose in the Islamic empire I discover how mathematics and experimentation Fus together as the Empire embraced a medieval Industrial Revolution and incar I find out how these ideas led directly to today's world of science and [Music] technology science and Islam continues next Monday night at 11:25 tonight we're heading for broadcasting house and a day out with you too [Applause] [Music] [Music] every now and then an idea takes form that changes everything it's revolutionizes the way we see and understand the world around us I believe that just such an idea took form in the medieval Islamic world it's the idea that everything from the stars above to the workings of our own bodies is not arbitrary or whimsical but subject to certain systematic rules and what's more that we humans can work out what those rules might be and then we can refine and test our theories through observation and experiment in other words it's the idea we now call the scientific method [Music] for me the story of the scientific Renaissance that took place in the medieval Islamic world is a personal one this is my cousin samir's house in the Iranian Capital tan I haven't seen some of the relatives on my father's side of the family in over 30 years this is my not so tall but very beautiful Auntie Ana the alkal family is originally from the city of nef in Iraq south of Baghdad in fact I grew up in Iraq but when Saddam Hussein came to power the family split many of the alkalis fled here to Iran as my mother's English I came to Britain with my parents there I pursued my passion for Science and am now a professor of physics at the University of Sor but now I find that my own scientific work and my Arabic and Islamic Heritage are intertwined on my journey through the Middle East I discovered that an astonishing leap in scientific knowledge took place here a thousand years ago under a powerful and flourishing Islamic empire wealthy powerful successful cultures will produce enormous advances in understanding and in technique and that's just what we find in Islam in Baghdad under a series of successful powerful wealthy and self-confident Islamic regimes over a thousand years ago the Islamic empire was the largest in the world it governed and estimated 60 million people that was over 30% of the world's population I found an archaeological fragment of this glorious past in a suburb of tran not far from my cousin's house these ancient walls tucked behind a back street on the outskirts of Southern Teran are literally all that remain of the ancient city of Ray the city that the great Persian geog al mad described as one of the glories of Islam of course Ray was just one of a number of cities that flourished under early Islamic rule from Baghdad its capital the empire spread across thousands of miles from North Africa through to central Asia cities like alasar Basra MV Gan bhara each powerful and thriving cities each would have been rich in trade alive with culture each would have had its own libraries its ownmy these were powerhouses of the new science this really was a golden age think of that span of land this is larger than any Empire human civilization had ever known within that span of land you can plug in the Roman Empire and it will fill just maybe what one third of it one half of it or something like that [Applause] [Music] reminders of this great Islamic empire are everywhere in the Arab world today this football match in the Syrian Capital Damascus is being played at the Abbasid Stadium that's the name of the family who ruled the Islamic empire from 750 to 1258 ad [Applause] this large territory allowed them to raise enormous tax revenues to fund a search for knowledge and scholarship which became known as the translation movement they sent Scholars around the known world to gather up great books and have them translated into Arabic it's a legacy that's still alive in the minds of most modern Arabs [Music] [Applause] [Music] [Applause] for medieval Islamic leaders scientific knowledge was crucial to successfully running a vast Empire they did have a big and sophisticated governmental Administration and obviously that needed knowledge if you wanted to be an administrator and you had to assess taxes you needed to know about mathematics it also wants to be able to build Monumental buildings that requires the knowledge of architecture and again mathematical skills to construct fine buildings safely medicine just to keep the elite happy and healthy and those are the areas of knowledge which are first translated from other languages into Arabic the legacy of the medieval Islamic empire is scattered across a vast region there's architectural masterpieces like the omad mosque in Damascus the jam mosque in Isfahan and Al ashar University of mosque in Cairo and then there are many ruins that still hint at past glories like this a crumbling 8th Century Palace deep in the Syrian desert and this a huge Muslim palace called Medina Zahra currently being excavated in southern Spain these are the impressive ruins of Medina to Zahra the Fantastic Palace City built outside Corda in the 9th century by abdur Rahman III who was the greatest of all the Andalusian cffs at the time that it was ruined Cordoba was in fact the largest and most important city in Europe arrival to Baghdad in the East for a center for Islamic scholarship and Science and as I traveled I saw how science especially numerical recordkeeping and measurement was crucial to dealing with the challenges of running a vast Empire this is the mighty River Nile as it flows through the Egyptian Capital Cairo since Antiquity its unpredictable floods have determined the fate of Egypt's people bringing years of lean and plenty by the 8th Century Cairo was part of the Islamic empire and the new rulers took the first step to understanding this Mighty River in a scientific way they built a device to measure it amazing structure Dr Nardo Al bizer of The Institute of ismi studies is showing me the nilometer it's basically a huge colonade that was built in a chamber connected by tunnels to the river as the water Rose or fell its height could be read from the central column the central colonade here is ultimately a measuring uh instrument it is very precise it's almost one inch between a marking and another presumably they need to know seasonal variations in the Heights and to the mark try to have some sort of record so that they could measure against certain years where a year was known for a high level of Flood versus another year known for its drought then they might perhaps take some precautions yes the data collected from the nilometer did have one practical use by creating an objective record of the river's Behavior it allowed the rulers of the time to calculate how much tax to levy on Egypt's Farmers but whatever its use is what I love about the nomer is how it shows that to understand the world you have to build devices to measure it if you think very hard it's never obvious that measurement can make sense of the world around us the world appears as a western philosopher once put it like a buzzing blooming confusion and the idea that we as a group have tools which are reliable which have sufficient Integrity which have an intellectual grip that can make sense of the basic phenomena we see around us that's an astonishing idea and one medieval Islamic ruler made measurement a personal Obsession giving it a scale and ambition that was truly unprecedented his name was el- mmon and he became the cff or ruler of the Islamic empire in 83 ad El mmon lived in a culture without portraiture so all we have are later impressions of what he might have looked like elmm Moon funded a range of scientific research but one particular project was a personal favorite of his and given that he ruled over such such a large territory it's hardly surprising what it was mapmaking in the second decade of the 9th century ad El mmon commissioned a new map of the world and his scientists did a pretty impressive job it was a vast Improvement on all maps that had come before what we see here is that they've really got the the Mediterranean uh it shape and how it links in with the Black Sea the middle e even the whole of Asia as far as China and Japan they've even got the the Indian Ocean and the east coast of Africa it all looks pretty impressive for the known world at the time of course what Al mmon ultimately wanted to know was how much of the Earth as a whole did he possess and this beged the question just how big is the Earth it's a sign of amazing ambition that groups of Scholars and Craftsmen together can as it were capture the world where does that ambition and that confidence come from part of it comes from uh religious Faith because the world was made by someone a bit like us but much smarter if we're smart enough the thought was we could probably make sense of a bit of what he did and that's very clear as a motivation in a lot of Islamic as in a lot of Christian Science and more specifically the practice of Islam demanded that its followers have a very clear idea of the size and shape of the world now this is crucial information for Muslims because wherever they are in the world they need to know the direction to mecca for their prayer this is known as Al now over such a large territory finding the direction to Mecca is not a trivial problem this problem was wonderfully Illustrated when a mosque was built recently in Washington DC some worshippers were confused because the direction they were told to face when praying was slightly North and not Southeast as they expected after all Mecca is southeast of Washington and on a flat map it does appear to lie in that direction but on a curved sphere the shortest distance between any two points follows what's called a great circle so for example this great circle line between Washington and Mecca is quite different to what you might expect so the direction to Mecca from Washington actually points slightly Northeast rather than Southeast of course this is complicated stuff but the key point for Islamic scholars is that knowing the direction to Mecca requires a knowledge of how steeply the Earth curves and that means knowing how big it is so Elma Moon commissioned his very best scientists to measure it hello hello I'm jar nice to meet you to understand how they did it I'm meeting up with Professor Sami Ubi from Aleppo University in Syria who's an expert in early Islamic science join me Professor chalbi began by explaining the measuring technique which elmon scientists first used and which they had inherited from the Greeks we're now talking about this the earlier Aristophanes um technique of measuring the circumference it was repeated again by the the abased astronomers was to measure the distance between two points and then look at the angle of inclination of the Sun so in Egypt in Aswan down in the South they regard the Sun as being vertical this is you know near to the equator and they worked out how far away from the vertical the sun was if they measured it from the north of Egypt in Alexandria which is on the Mediterranean Coast Elm Moon's astronomers repeated the Greek experiment in Syria and Iraq by measuring the angle of the Sun in the sky at noon at one known location they then walked due north to a second location carefully measuring the distance they traveled at the second location they once again measured the angle of the Sun at noon this angle would have been slightly smaller than the first one with these figures elmm Moon's astronomers were able to estimate the Earth's circumference they got a value of 24,000 M within 4% of the correct value not bad you might think but this method was flawed and ultimately unreliable the main problem with it was that measuring the distance between two locations was incredibly difficult it could only be done by the unreliable method of counting Paces as you walked through the burning desert a more reliable and sophisticated method for estimating the Earth's size was needed and two centuries after elmm Moon died it came what made it possible was a great leap of imagination and the fact that by 900 ad much of the world's mathematical knowledge had been translated into Arabic so Scholars could scrutinize and improve on it out of this obsession with scholarly learning came a true mathematical visionary Abu ran Muhammad IB Ahmed Ali and like all Islamic scholars of the time alboni was obsessed with the Science and Mathematics of the ancient Greeks Babylonians and Indians and because of the success of the translation movement he had literally on his desk the great work on Geometry by euklid toames alest the Indian text the sind and the famous work on algebra by Al karisi Professor chelbi has brought along the book in which elb Rooney describes how he combined algebra and geometry with some very simple and practical measurements to solve the Epic Problem of how to calculate the size of the Earth this is this is hisi the masi cannon yes this is Boon's Cannon which I've been trying to get hold of um where he describes this this fantastic experiment and oh and you found the page yes having read elon's description of how to estimate the size of the world I wanted to try it for myself first he had to find a fairly high mountain from the top of which he could see a flat Horizon in this case the sea what I love about this story is that with a few simple measurements around this small mountain peak you can work out the size of the whole world ALB Ro's First Step was to work out the height of the mountain he did this by going to two points at sea level a known distance apart and then measuring the angles from these points to the Mountaintop so to measure the angle to the Mountaintop Boon had to use a device like this called an astrola it's basically a giant protractor it has the Angles and degrees marked around the outside and a pointer to help him determine his line of sight so if we try now and determine the the angle to the top it has to hang freely and then okay so you let it hang I'd like to stress if you haven't noticed already that Alber rooni would have made his measurements more meticulously than I am he did them again and again to get consistently reliable results okay that's about it and that is 242° okay so now we've determined one angle we now have to go and pick our second spot along the beach the distance from the first to the second points must be measured accurately in this case case is 100 m and the two points must be in a straight line with the mountain I measured the second angle to be about 262° and now had enough information to calculate the height of the mountain using trigonometry and algebra elb Rooney used a formula that relates the height of the mountain to what are known as the tangents of the angles he measured using my measurements I get a figure for this mountain of about 530 m i now need only one more measurement to get the size of the Earth and to get that I have to climb to the top of the mountain what beon did next was measure the angle of the line of sight to the Horizon as it dips below the horizontal so we're going to try and reproduce that so if you can lift it up so that it's hanging and if I locate The Horizon okay which is about half a degree which is about the value that beon got now here's the really ingenious part beoni had measured four quantities three angles and a distance he used two of the angles and the distance to work out the height of the mountain ALB roon now had everything he needed in essence ALB roon imagined a huge right angled triangle which has as its three corners The Mountaintop The Horizon and the center of the earth trigonometry told him that the angle he had measured and the height of the mountain are related to the radius of the Earth and algebra allowed him to calculate it with this formula beon is able to arrive at a value for the circumference of the earth that's within 200 miles of the exact value we know it to be today about 25,000 mil that's to within an accuracy of less than 1% a remarkable achievement for someone a thousand years ago [Music] for me Boon's experiment is an early dramatic example of a scientist using mathematical reasoning to extend Humanity's reach he really pushes the idea that abstract geometrical rules governing idealized shapes like perfect circles and triangles can help us to comprehend the real world Einstein used precisely the same approach admittedly with much more advanced mathematics ICS when he developed his general theory of relativity almost a thousand years after beoni but both Einstein and beon were United by a single common idea with mathematics Humanity can embrace the universe in this story of the birth of the scientific method the Islamic Scholar's ability to master sophisticated mathematics is the first crucial [Music] ingredient the second crucial ingredient is the use of experiments in science without experiments Theory remains meaningless and sterile it's experimentation that allows Theory to be held up against the real world it gives it physical meaning but whereas sophisticated mathematics grew out of the Empire's obsession with the world's learning through the translation movement practical experiments came from the daily needs of a powerful and expanding civilization the driving force of the expanding medieval Islamic empire was trade it boomed from around 700 AD onwards creating a massive demand for metal workers glass blowers tile makers Craftsmen of every possible kind when this collided with scholarly tradition symbolized by the translation movement it had seismic consequences for science the scienes absolutely depend astronomy is a wonderful example chemistry is other on really intense relationships between craft traditions of instrument making of working with metal and fire of working with medicines drugs plants and scholarship highly sophisticated literary and mathematical analysis and the Islamic world is just such a place by around 800 ad the great cities of the Islamic empire dominated the World's Trade to its markets came silks spices drugs fruit perfumes and gold from as far a field as India and China in the East and Spain in the west anything that could be traded was [Music] a wonderful relic of this medieval trade boom are the great Caravan s like this one in the Syrian Capital Damascus this huge vaulted building was designed as a resting place for all the Traders and their animals who visited the [Music] city on their ground floors were wide spaces for animals and goods and above there were rooms for the rich Merchants to refresh themselves before another day of [Music] haggling one 10th Century traveler talks of the riches and beauties of the bazaars and that the income of the provinces and localities was between 700 and 800 million din markets like this in the Egyptian Capital Cairo still capture the intensity of medieval trade and still surviving in the modern world of the internet and the mobile phone is a fantastic example of how Traders a thousand years ago communicated across a vast Empire so so this is a carrier pigeon it Bas is here so wherever you took this pigeon all over Egypt it will make its way back to this guy there's a famous story that a rich Cairo Merchant by the name of Anor wanted to grow cherry trees so he sent a message with a carrier pigeon took contact of his in Damascus asking for some seeds his contact sent back 500 Birds each one carrying a small bag with seeds in it the whole process took just three days sort of a medieval FedEx really [Music] by 700 AD the Islamic empire was taking the first steps towards mass production and in this world where knowledge of materials metals and how they worked became increasingly important one practice flourished it's the practice that was inextricably linked with magic specific speically the dream to turn base Metals into gold the mysterious practice of alemy the Ancient Art of alchemy was a mystical system of belief based on spells symbols and Magic but I believe it took Islamic scholars to turn this quasi religion into something much more scientific chemistry increasingly the knowledge of the Alchemists found more and more practical applications for instance when during the last decade of the 7th Century the ruler of the Islamic empire Abdul mik made the Bold decision to create a common currency for all his dominions he turned to Alchemists for help the proportion of gold to other alloyed metals that you have to put into the din to make the din usable otherwise pure gold will become uh very soft and you can't use it so that proportion is adjusted by believe it or not in this period the Alchemists it is the Alchemists who knew how to combine Metals together and how to get the proportions of this gold to Silver and Gold to bronze and so on I hunted down tangible evidence of the skill of medieval Islamic Alchemists in the old markets in the Syrian Capital Damascus this is an Islamic din the date of this 128 after hij so the middle of the 8th Century 7 almost 7 this 1300 year old coin made of an alloy of different metals isn't just durable it's also malleable enough to be inscribed with intricate Arabic writing no God and of Allah and coin making is one of the many examples of how the Practical needs of a booming economy began to turn the magical practice of alchemy into modern chemistry what striking about chemistry in the medieval Islamic world is the sheer quantity of manuscripts that deal with the subject there are literally thousands that survive dealing with subjects as varied as metalogy glass making tile making dying perfumery Weaponry there's even a description on how to distill alcohol all this activity clearly points to a bustling economy with consumers soldiers Engineers Architects all demanding Innovation and all demanding new technology a great example of applied chemistry in the medieval Islamic world was the manufacturer of soap this stuff solid soap that you can really clean yourself with was virtually unknown in northern Europe until the 13th century when it started being imported from Islamic Spain and North Africa by that time the manufacturer soap in the Islamic world had become virtually industrialized the town of Fez boasted some 27 different soap makers and cities like Nabis Damascus and of course Aleppo became world renowned for the quality of their soaps a 12th century document has the world's first detailed description of how to make soap it mentions a key ingredient and it's a substance that became crucial to Modern Chemistry an alkaline now alkaline substances are crucial to soap making but what's interesting is that our word Alkali derives from the Arabic alali which means ashes that's because back then alkalis were manufactured From the Ashes of the roots of certain plants like salt warts Islamic chemists new understanding of alkalis and other new chemicals gave another industry a lift to Glass making the Islamic chemists discovered that they could change the color of glass using newly discovered chemicals like manganese salts and they built industrial furnaces some several stories high to manufacture glass in huge quantities the legacy of their skills can still be seen in beautiful stained glass windows Islamic chemists also developed many other colors pigments and dyes using their new alkalizes and metals like lead and Tin these helped Architects to decorate mosques like this one in the Iranian city of Isfahan in a glorious range of colors and designs chemistry was also driven by the booming markets in perfumes in the main Market in Damascus Traders still make up your favorite scent as they would have a thousand years ago so it's basically has a base of alcohol and then he adds to it the uh the oils from the plants that you want Jasmine and and and Rose Water and mint but these days they'll they'll use um very nice yeah I think I'll buy some of that perfumers pushed chemists to come up with ever more ingenious techniques for extracting subtle and fragile fragrances from flowers and plants they responded by refining and really establishing a technique that all chemists would instantly recognize today distillation many of the techniques originate with Islamic scholars or even earlier Dr Andrea c a chemist from University College London shows me how distillation was used distillations would have been done in devices sort of related to these this is what's now called a retort and we don't really use them anymore but retort comes from from the word to bend in other words a flask which has been bent over and that's crucial well many of the Techni the shape means that a gas produced in the flask is forced to condense in the spout and it's the main way of extracting scents from flowers and plants now the idea here is that you heat at this end and you collect at the other and so we should actually take a look and see if we can do a quick distillation with rose petals first we need to just put in a little bit of water the water and steam will essentially control the temperature what we don't want is for this to get too hot um because the trick with this kind of distillation is to use heat to release the scent molecules but at the same time making sure that these delicate substances aren't destroyed in the process you actually use the steam to control the temperature and the steam will carry the those smells over you can see the liquid coming up condensing in the long tube and there is already liquid coming coming over and that should be carrying with with it some of the sort of rose water smell yes you can really spell it this picture shows a 14th century perfume Distillery Middle Eastern perfumes were known to have been sold as far away as India and China the Islamic chemists also played a pivotal role in another more gruesome industry Weaponry historical records during the Crusades talk in terrified tones of how the Muslims would attack the Christians with burning missiles and grenades striking fear into the hearts of the Defenders many of these use a substance known as Greek Fire Islamic chemists improved on Greek Fire by using and refining a naturally occurring resource petroleum they developed the idea of distilling petroleum or nft to create a lighter extremely flammable oil which they mixed with other volatile chemicals to make them burn furiously and the result was clearly terrifying what all these medieval Islamic texts on chemistry have in common is their great attention to detail which is clearly based on careful experimentation in fact the whole idea of a laboratory where chemical and Industrial processes can be tried out really takes hold at this time the Ingenuity of medieval Islamic chemists is impressive but I wanted to know something deeper what contribution did they make to our modern understanding of the principles behind chemistry this is the center piece of modern chemistry the periodic table it lists all the known elements its key idea is to group substances with similar properties together on the far right for instance are the inert gases on the far left are the volatile Metals the periodic table is a Triumph of classification giving scientists a way of organizing their knowledge of the material world classification is is simply a way to to think clearly I mean what you need when when you when you have some ideas about how the world works is that gives you a kind of schema and you chop the world up into categories and that actually helps you to understand to to to to make sense of what's around you people had been trying to classify the material world since ancient times the Greeks for instance thought there were just four worldly elements air Earth fire and water but this idea was was a philosophical one and had little practical value and that's what medieval Islamic chemists really changed they used experimental observations to classify the stuff the world is made of at the Forefront of this was a medieval Islamic doctor and chemist called iban Zakaria al- razi who was born here in the city of Ray just outside the Iranian Capital Teran in 865 ad elzi's classification was very different from the Greek one he argued for instance that minerals roughly stuff we dig out of the ground should be classified into six groups depending on their observed chemical properties the same guiding principle that lies behind the modern periodic table now what I've done is I've brought materials from his classification scheme and we have here what we would what he called the spirits we have the alic bodies we have the stones then we have the atrament the salts and finally The Borax each of elzi's groups had a profoundly different experimental behavior for instance Spirits were flammable the metals were shiny and malleable salts dissolved in water of course these classifications are not the way we do it today but the point is that for the first time elrazi was grouping substances on the basis of experimental observations not philosophical musings we've come over a thousand years since the work of arazi what sort of debt does Modern Chemistry owe to him for his classification well I think with razi we start to see the the the first classification which really leads on to further experiments the first schema which allows people to start doing rational work and so really he lies at the start of of almost formal chemistry which ultimately leads to our periodic [Music] table I believe that what we see in the work of the Islamic chemists and Alchemists is the first tentative steps to a new science yes by our standards it contained a lot of magic and Mumbo jumbo but it placed an emphasis on experimentation that was truly revolutionary but bigger and better was to come because Islamic mathematics and the experimental techniques of Jabar and hayan and arazi were about to be welded together in a completely Innovative way that would revolutionize their work and create the modern scientific age until the 9th or 10th centuries ideas about science and how the natural world worked were dominated by the Greek philosopher Aristotle and they were very different from ours today he believed that mathematics was concerned only with an abstract world of perfect forms of idealized shapes like circles squares and triangles it had no power to explain what we observe in the world around us a world character ized by irregular wonky shapes and constant change physics is a Greek word meaning the science of change and for the classical Greek tradition there was a strong sense in which the science of change was in contradiction with mathematics mathematics dealt with perfect knowledge with the unch changing world of mathematical forms and it seemed in principle extremely unlikely that processes of coming into being and passing away of growth and of decay of qualitative change could be captured with the beauties of geometry and Mathematics the story of how Humanity shook off this idea and began to see that mathematics is actually an incredibly powerful way of describing the world around us is long and complicated but for me Islamic scientists played a crucial role and I believe one man really LED this movement to turn mathematics from a language of abstract thought into a truly practical science he was like me from Iraq and his name name wasam what alham and his contemporaries argued for was the possibility in a way of a single science which would be both mathematical and philosophical which would link together a physics a science of change with a mathematics a science of quantity and that seems to me to be radical and crucial for the construction of new forms of Rel reliable knowledge iel haam was born in 965 ad in the southern Iraqi town of Basra and other Scholars regarded him as a prodigy he shot to Scientific Fame just after the turn of the first Millennium and was an incredibly Innovative and Brilliant scholar his reputation as an intellect spread throughout the Empire but it was this reputation that would almost cause him to lose everything when he took up the poison Chalice of trying to tame one of the world's greatest Rivers there's a wonderful if suspiciously apocryphal story about how iel Ham's career as a scientist was transformed it concerns the Nile and how just after the turn of the Millennium nnel haam was asked by the ruler of Egypt to find a way of controlling it could he prevent its unpredictable and potentially devastating floods and droughts but it didn't take imel haam long to realize that the Nile was way too large to control on hearing this the califf flew into a terrible rage and ordered iel Ham's execution iel haam responded by feigning Madness the execution was called off and he was placed under under house arrest there with time on his hands to contemplate The Story Goes iel haam considered deep and fundamental questions in physics and he began with a truly enigmatic and Universal problem he asked if the wonderful and entirely mysterious nature of light and vision could be explained by mathematics and geometry under house arrest or perhaps here in the rooms of Al ashar University in Cairo IAM carried out a series of experiments that created the modern science of Optics I'm with Dr Al bizri who has carefully studied imam's work he explained that I haam first considered the Aristotelian explanation for how we see an explanation that was completely could say a tree its essence or form emanates from it and then mysteriously flows into our eyes so if I'm uh for instance now looking at the buildings and the trees on the banks of the Nile uh I'm receiving the forms of these buildings and these trees uh in the eye abstracted from their matter according to Dr albis found this idea deeply unsatisfactory he wanted a mathematical explanation and looking back at existing Greek writings he found one although it was obscure and bizarre this idea claimed that we see because light rays come out of the eye ultimately it says that Vision occurs by way of the emission uh from the eye of light that is shaped in the form of a pyramid or a core this cone shaped beam illuminates what we're looking at and is defined by nice geometric straight lines it seems haam liked this mathematical approach but immediately spotted its flaws if we see he asked because light comes out of the eye why does it hurt when you look at a bright object like the Sun but not hurt when you look at something dim or at night can light from our eyes really be lighting up distant objects in the sky so in an inspired piece of thinking IAM combined the two Greek ideas and defined our modern understanding of light and vision light he said does travel in straight lines that obey geometric laws but instead of them coming out of the eye these travel into it it is the development of an entirely new Theory and also methodologically it is the beginnings of mathematizing physics whatam did was take the principles of geometry with its rules governing straight lines and apply them to the real world he then designed experiments which would test whether the real world measured up to his mathematics in about 1020 iel haam published his groundbreaking geometric explanation of light in hisab manad or book of Optics and what really marks this book out as science is that iel haam carefully justifies his theories with detailed experiments that others can repeat and verify he starts from first principles to find out how light travels for his first experiment iel haam wanted to test the idea that light travels in straight lines now to do this he took a straight tube on which he drawn a straight line down the side and a ruler again with a straight line down the length of it and by matching the two together he was convinced then that the tube was straight now if he uses it to look at an object in this case a candle he can see the candle through the tube which is good evidence that the light is traveling up in a straight line but just to be sure he then blocked the end of the tube and then by looking at the candle again of course he can't see it because what this does is confirm that the light doesn't travel to his eye via any other route in a curved path outside the tube proof that light only travels in a straight line now this might sound quite trivial and obvious to us but IAM was starting from first principles then through experiment he extends his light travels in straight lines idea to many other phenomena he explains how mirrors work by arguing that the angle the ray comes in at is the same as the angle it bounces off at he explains what we now call refraction why objects look kinked in a glass of water are arguing that light rays Bend when they move from one medium to another and then he tackles the nature of vision IAM wanted to understand how an object makes an image on the retina of the eye so he built what he believed was a stripped down version of the eye which is basically a black box with a tiny hole in it this is what we call today the camera obscurer he next took his subject in this case Anna is very brightly lit and we now go inside the box to see what the image looks like now that I'm inside the camera obscurer and I've allowed my eyes to get used to the dark we can open the hole and there we clearly see the image of Anna waving on the screen but the image is inverted because light travels in straight lines and so the light from her head has to move diagonally downwards to hit the bottom of the screen and light from from her feet travels diagonally upwards to hit the top but more importantly what this proved to inel hm is that there's a onetoone correspondence between every point on the object on Anna and every point on her image on the screen just like a modern scientific paper the attention to detail in theab manad is incredible his book isn't just a dry scientific Treatise it's a manual for f future Generations in his work he constantly justifies his theories about light with experimental observation and he describes his experiments in great detail so that other people can repeat them and confirm his ideas his messages don't take my word for it see for yourself I believe that I haam was one of the very first people to ever work like this this for me is the moment that science itself is summoned into existence and becomes a discipline in its own right what I find so impressive about iel haam is how once he arrives at his mathematical theories he then uses them to extend our knowledge of the real world so for instance he used his new ideas about light to deduce that the Earth's atmosphere is of a finite thickness and he even estimated what that thickness is he did it basically by measuring how long Twilight lasts he rightly assumed that the reason it continues to be light after the sun has dropped below the Horizon must be because its Rays Bend as they enter the Earth's atmosphere the length of Twilight and an educated guess for what we today call the Air's refractive index gave iel haam a way of estimating the thickness of the Earth's atmosphere he came up with a figure of around 40 kilm about half of the modern value that's pretty impressive it really shows how mathematics extends the power of science to explain on my journey so far I've been overwhelmed by the sheer intellectual ambition of medieval Islamic scientists when their leaders asked them to find out the size of the World Scholars like ALB roon used mathematics in startling new ways to reach out and describe the universe and as trade and commerce boomed scientists like Al Razzi responded by developing a new kind of experimental science chemistry but if there's one Islamic scientist we should remember above all others it is in my view IAM for doing so much to create what we now call the scientific method the scientific method is I believe the single most important idea the human race has ever come up with there is no other strategy that tells us how to find out how the universe works and what our place in it is of course it's also delivered technologies that have transformed our lives so the next time you jet off on holiday or use a mobile phone or get vaccinated against a deadly disease remember I haam IB Cena El Boni and countless other Islamic scholars a thousand years ago who struggled to make sense of the universe using crude mirrors and astrolabes they didn't get all the right answers but they did teach us how to ask the right [Music] [Music] questions in the next episode I travel to Syria and Northern Iran to find out about the great Islamic scientists who revolutionized astronomy making it a truly modern science and I'll also discover how the man many consider to be the father of the European scientific Renaissance cernus borrowed from Islamic astronomical theories and I'll unravel the mystery of how the Golden Age of Islamic science came to an [Music] end and there's more from science and Islam next week next night plunging right into the thick of it with more biting comedy [Music] [Applause] [Music] the Sun the moon the planets and stars have always fired our imaginations and fueled our mythologies and studying the heavens astronomy is surely the oldest scientific discipline there is what's really unexpected I guess is that astronomy has repaid our interest in it over the centuries time after time it's been the place where new ideas have emerged and it's often led the rest of the Sciences I'm a professor of physics at the University of su and the ideas and theories of the great European scientists like Galileo muttin and Einstein lie at the heart of my work but there's another side to me I'm half Iraqi and I'm Keen to investigate stories I'd heard as a school boy in Baghdad of great astronomers from the medieval Islamic World whose work shapes the discoveries of these later Western SCI scientists so I'm going on a journey through Syria and Egypt to the remote mountains in Northern Iran to discover how the work of these Islamic astronomers had dramatic and far-reaching consequences there I'll discover how they were the first to attack seemingly unshakable Greek ideas about how the heavenly bodies move around the earth it was Islam that paved the way for one of the greatest upheavals in the history of science [Music] [Music] this is the University of Padua in Northern Italy I'm here to see incontrovertible evidence that one of the greatest breakthroughs in European science links back to the earlier work by Islamic scholars because it was a news one that that time astronomer Dr Louisa piotti and I are climbing up to the 18th century observ at the top she promises to show me one of the most important books in scientific history so what do we have here okay this is the second edition of ricus yes this is the revolutionibus orium celestium which was published in 1543 by the Polish astronomer Nicholas cernus I'll be careful the significance of this book is enormous in it cernus argues for the first time since Greek Antiquity that all the planets including the Earth go around the Sun for thousands of years everyone had believed a very different view that the Earth is static and everything including the Stars sun and planets move around it and here the all his system okay oh here we go system the sun in the middle it's a famous drawing this one oh yes and there's yes there's teror with the moon going around it okay yes this is an astonishing book and many historians credit it with starting the European Scientific Revolution the first crucial step in a journey that led to Modern physics well I agree but it does seem a bit odd that one doesn't hear much about where cernus got his ideas and information the impression is that they came out of nowhere the beginning the beginning is all in in Arabic it certainly is a real Revelation to me that he explicitly mentions a 9th century Muslim for providing him with a great deal of observational data an astronomer who lived in Damascus called elbani like all the great scientists of the Islamic empire elbani lived in a culture without portraiture all we have are later impressions of what he might have looked like and here he mention parus calipo me and so on and he started to mention what he call MAK means Alat okay and then this second book here the second book is oh we can look at the beginning in Latin I see we can open cernus in fact made extensive use of elani's observations of the positions of planets the Sun the moon and stars he worked with Latin translations similar to this one of the Syrian astronomer's data so this is Ban's Z is his his book of Star Charts so it has the Arabic yes all the Arabic PR yes and then the Latin version that's convenient ah but he certainly he had the data the observational data by Al batani and you know he and copernicus's book is full of clues that hints at other past sources and though alberani is the only Islamic astronomer cernus actually names recent detective work has uncovered clues that cernus based many of his ideas on the work of other Islamic scholars the clearest example is cernus is use of a mathematical idea devised by the 13th century Islamic astronomer El tusi called the tusi couple back in England I compared a copy of Al's with another edition of Cernic's revolutionary bus in it there's a diagram of the tusi couple and there's an almost identical diagram in Cernic's book even down to the letters that Mark the points on the circles so in elzi there's the Arabic Al if which is a there's the ba which is B G over here is the G and the Dal at the center D it's a remarkable similarity now this might just be coincidence but it's pretty compelling evidence in fact I truly believe that cernus must have been aware of alu's work and other Islamic [Music] astronomers further detective work also shows that cernus used mathema iCal ideas for planetary motion that are remarkably similar to ones developed by another Islamic astronomer a 14th century Syrian called IAT for some historians this cannot be coincidence Copernicus to me I have no proof I don't have a Smoking Gun but to me it looked like and again by analyzing his own works it looks like he was working from diagrams somebody gave him a a geometric diagram of what was done by I shat to solve the problem of the moon for example to solve the problem of the upper planets to solve the problem of the movement of mercury he had diagrams and he was genius enough to be able to figure out from the diagrams what was the underlying theory behind those diagrams so far from emerging from nowhere it seems cernus is work will be better described as the culmination of the preceding 500 years of Islamic astronomy I wanted to investigate this story find out more about those astronomers and their ideas but before that I wanted to investigate an even deeper question what actually motivated medieval Islamic scholars interest in astronomy [Music] [Music] this is the umed mosque in the heart of the Syrian Capital Damascus and is one of the oldest in the [Music] world and I'm here on a kind of treasure hunt well it it says in the books that there is a sun dial on the top of the arus minate the bride minate over there so we'll see whether it is there or not so this is Dr re turkmani an astrophysicist and medieval astronomy expert from Imperial College London and we're looking for one of the most accurate Sund dials made in the medieval world and equally exciting for me is the fact that it was made by one of the Islamic astronomers who had so heavily influenced cernus I Shad let's see officials in the mosque claim that the Sundial was removed in the 19th century but Ream's research suggests that an exact replica might still exist high in one of the minettes Hidden from view it's not quite the Lost Arc of the Covenant but the idea of discovering a 150y old artifact is still quite something would would you recognize anything if you had I need to look that off the other window sorry no no it it is further up yeah marking time accurately is essential to Islam the Quran requires the faithful to pray five times a day at five very precise times at the exact moment of Dawn when the sun is overhead in the afternoon moon at Sunset and then again at the moment of Nightfall so for early Islam an accurate Sundi was an extremely important fixture in many mosques that's it that's it I found it I found it here is that's it look just as descri in the it's hidden by the hill yeah no wonder they didn't know that it exists here it's all covered with the pigeons F pigeon crap yeah oh oh great thank you try that so let's see now this consist of three candiles you know the main big one and there's the northern one and the southern one there is a line here for Salat the the midday prayer and there is one for the afternoon prer innat had calculated the arrangement of these lines so that the Su dial remains accurate all through the year even though the length of the days change they will have the eke keeper you know it's a very important job so he would sit here watching the shadow exactly and exactly the precise moment for prayer he'd signal to them then to start to the call for prayer exactly okay [Music] accurate to within minutes really showed me how Islam required its Scholars to make meticulously accurate observations of heavenly bodies and I began to understand why kernus was so impressed by the work of his Islamic predecessors they really brought standards of accuracy and precision to astronomy that were unheard of before they' calculated the size of the Earth to within 1% and created trigonometric tables accurate to three decimal places and when I met up with re turkmani again on Mount kasun outside Damascus I was to hear about the Islamic astronomer who personified accurate observation the man whose astronomical tables and measurements cernus explicitly makes reference to alberani born in 858 in southern turkey alberani made accurate astronomical measurements a personal Obsession and the story goes is that alatan used to observe on this mountain here in that in this Observatory over 40 years from 877 both here and in the town of raka Alban's great project was to work out as accurately as possible the length of the Year this is a copy of the original manuscript okay so I'll show you the chapter at which he explained the length of the Year okay mhm the the chapter 27 so he first start here by citing the ancient valleys of the Egyptians and the Babylonians right and he gives on the vi their estimate of the year was 365 days 6 hours and just over 10 minutes to improve on this elbani used his Ingenuity and a device like this an armillary sphere he used it to measure how the length of Shadows varied over the course of the year with this information he was able to work out the precise day on which it's both light and dark for exactly the same time the so-called Equinox and he repeated his measurements over the course of 40 years now here's the clever bit he examined a Greek text that was written 700 years earlier and discovered the precise day on which its author had also measured The Equinox he now had two vital pieces of data the number of days between the two observations and the number of years he divided the first number by the second to arrive at an astonishing result a year is 365 days 5 hours 46 minutes and 24 seconds and he gets the new number which was only 2 minutes of the modern observations two minutes two minutes of only the late of a year to is an two minutes exactly the one he calculated what's astonishing about the accuracy of elani's measurements is that he had no telescope he used an armillary arm his naked eye and devices like this an astrolab so you move the pointer and you move this disc with it to points towards the North Star then this small pointers here they will give you the location of the rest of the stars and the planets despite this among his many other observations is an incredibly accurate figure for the Earth's Tilt of just under 24° about half a degree from the figure we now know it to be and he didn't stop there he measured variations in the diameter of the Sun to such accuracy that it led him to an astonishing conclusion this distance the furthest point the Sun reaches from the earth during the year known as the the apy actually changes from one year to another also his tables showing the position of the sun and the moon which is what cernus refers to some 600 years later set a new standard in precision and accuracy so alberani and his fellow Islamic astronomers were clearly good observers but so what you might ask well the answer is that their observations began to suggest to them that the prevailing Greek theory that described how everything in the heavens revolved around the earth had some serious flaws this Greek tradition which had been unquestioned for over 700 years was based primarily on the work of one of the greatest astronomers of the ancient world Claudius tus or toy was a Greek astronomer based in Alexandria in the 2nd Century ad he wrote one of the greatest texts in astronomy the elest which was basically a distillation of All Greek knowledge on the celestial World Tommy believed that the Sun the moon the planets and the stars all sat on crystal spheres that rotated around the earth so the moon sits on the innermost sphere followed by the sun and the planets and finally a patchwork of stars on the outermost sphere so we human beings sit at the very center of the universe with the rest of the universe rotating around us but as Tommy himself realized there's a problem with trying to describe the heavens as a place of mathematically idealized perfect spheres and that is that the planets don't really play ball as they move across the night sky they change speed appear to get bigger and smaller and even go back on themselves Tommy tried to explain this away by arguing that the planets sat on small spheres called epicycles which rotated around a bigger sphere called a defant this explained why they might look as though they were changing size and why they sometimes even change direction unfortunately that still didn't fit all the facts it didn't easily explain why the planets appear to speed up and slow down so rather desperately toy fudged his model further by moving the Earth away from the center of the deference and having the deference rotate around an arbitrary point in Space the equant but now The Works of astronomers like alberani started to strain Tommy's ideas to Breaking points their careful observations began to suggest that even with tm's unwieldy equence and deference the actual behavior of the heavens didn't fit the data so what do you do if you were an an astronomer living in Baghdad and you have all those results on your table the very first requirement is say ah this Greek Trad is not as trustworthy as it is advertised to be and now of course they begin to say if the fundamental values of the astronomical tradition of the Greeks which we could double check and we found them to be in error what else is in error they began to question now the more basic foundational astrolog astronomical cosmological foundations of of of the Greek tradition and question they [Music] did what's absolutely striking about the writings of Islamic scholars by the 9th century is the increasing use of the word shuk which in English means doubts they showed that it's sometimes necessary to doubt an idea that everyone around you believes unquestioningly Islamic doubting of Greek astronomy began began the slow process of undermining the notion that the Earth is at the center of the universe to doubt takes great courage and Imagination but if the great dialogue between Islamic and European astronomers shows anything it's that doubt or shakk is the engine that drives science [Music] forward one of the first great shakk scientists was called haam he was born in the Iraqi city of Basra in 965 ad and was among the first to argue passionately that scientific ideas are only valid if they're mathematically consistent and reflect reality and when he applied his Fierce rigorous intelligence to Greek astronomy he immediately spotted that there was a fundamental contradiction at its heart on the one hand Greek cosmology argued that everything in the heavens revolves around the earth on the other hand Tommy in his Elma argued that if you want to mathematically predict how the Sun and planets move you have to pretend that they go around an arbitrary point in Space the so-called eent this is clearly a contradiction the heavens can't both go around the earth and not go around it at the same time time haam hated this nonsensical contradiction in the early 11th century he wrote a paper Al or doubts on toomy in it he writes with barely contained frustration Tommy assumes an arrangement that cannot exist says that is a total absurdity we cannot accept that and furthermore he says it's not a slip of a tongue pami knew that it was an absurdity and he shows us where pami himself was embarrassed by having to introduce it so he says there is a fundamental reasoning problem meaning that the Greeks knew that knew that he was making a mistake but he knew he couldn't do any better and hence now the challenge is to do one notch better and hence to be able to fix this that in my explanation begins to be the program of research for all astronomers to come in order to achieve that project you had to be convinced you had to be convinced that it was possible to make high precision mathematical models of the way in which planets and stars move that would really capture how they are in the heavens iel haam in effect laid down the challenge for all astronomers who followed which was to come up with an explanation for how the heavens move that is both mathematically consistent and agrees with what we observe the final answer to this would come from far away Europe with cernus and others but the next and crucial breakthrough came somewhat closer the top of this mountain in Northern Iran was the adopted home of the man who was the next of cernus Islamic influences nasin alusi he would succeed in rewriting Tommy's Theory which would ultimately lead to the overthrow of the geocentric view of the universe and so the birth of the modern scientific age this is the remote castle of alamut Eli's adopted home for many years it was the home of a Muslim sect called the ismaelis it's a lovely secluded spot and it was the center of the is movement it's not surprising that elzi would find a home here and it wasn't just him many other Scholars were gathered here and there seems to have been a library it was a Center for Learning as well as a military stronghold here this is the main gate Northern gate of the upper castle of Hassan a new archaeological dig is now revealing under the castle heun into the living Rock a Warren of rooms and studies a mosque and living quarters for this extraordinary community of soldiers and scientists this is the court of mosque or uh Center of of headquarter of Castle and it was Within These cramped conditions that Eli started his Masterwork of the shuk or the doubts the teira in it he finds an answer to iel Ham's first challenge how to eliminate Tommy's eent instead of a sphere rotating around an arbit point in space Eli devised a series of two nested circles which rotate around each other in such a way that they eliminate the equin the nested circles became known as a toi [Music] couple this is the mathematical system that Finds Its way into cernus is work some 300 years later having found a solution to the equence problem Eli now wanted to complete the task imel haam had started 200 years earlier to find a consistent mathematical description of the movement of the celestial bodies but to do that he needed better data which meant bigger and better equipment than he was ever going to find here at alamut and then something happened which changed Del's life forever the Mongols streaming in from the East an army of Mongols led by Huga Khan marched into Iran crushing everything before them by 1255 they had reached the foothills of alamut intent on its destruction then in a brilliant piece of diplomacy alusi managed to both save his own skin and satisfy his scientific ambition he visited the Mongol leader and played on his deep astrological Superstition convincing him he could tell the future if only he had new equipment alusi persuaded the Khan to make him his head scientist and to build him just a few hundred miles away perched on a Hilltop where the air was clear the largest Observatory the world had ever [Music] seen this is All That Remains of the Maraga Observatory the main instrument is hidden under this protective Dome [Music] alosi's new astronomical Center was based around a single large Building inside was an enormous metal Arc an arm millery arm 10 m across on its circumference were marked angles in degrees and minutes the scientists would line up the celestial object under study with a central point on the ark and then make make a reading from the markings on the ark giving them the definitive accurate position of the object in the sky the building was also surrounded by smaller astronomical equipment libraries offices and accommodation The Observatory even had its own dedicated mosque I suppose it is a little disappointing that there's not that much left of the place now so you really have to imagine what it must have been like back in its Heyday after all what alusi built here was nothing less than the world's greatest Observatory for 300 years and like any modernday uh International Research Institute he brought together the world's greatest astronomers from as far away as Morocco and even China I mean it must have been a really great buzzing atmosphere to work here with his new Observatory and worldclass team alosi was now ready to fulfill iel Ham's dream to try to make Tommy's model scientifically rigorous first they attacked the mathematics as well as the Tosi couple they invented other systems of planetary movement and with these new systems they were able to calculate mathematically consistent models for many of the celestial bodies Mercury Venus Mars Jupiter Saturn and the sun and moon alusi and the astronomers he brought together created what became known as the mara Revolution which was a complete paradigm shift in astronomy overthrowing the old toic view what Islamic scholars and astronomers like alusi do is to organize and make sense of mathematical astronomy at a level of unprecedented accuracy using instruments more precise than had been built before over longer time scales with predictions of the positions of planets and stars that no one had previously reached that at Moraga or at alamut we see I think genuine Revolutions in the level scale and intensity of mathematical astronomy but there was still a problem the new models were mathematically coherent and they dispensed with Tommy's unwieldy equant but but they still firmly placed the Earth at the center of the universe and that inevitably meant that their descriptions of the heavens were intricate and complicated with epicycles deference and couples it was like some great Cosmic [Music] gearbox it would require a huge leap of imagination to make the next step in our story and that next step would take place 2,000 miles from where I am [Music] now in my view the last phase of the Maraga Revolution took place not in Iran or anywhere in the Islamic empire but here in Northern Italy based on the work of Muslim Scholars places like the University of pad were already starting a new scientific movement the [Music] Renaissance back in Padua where I began my journey I Now understand why Islamic astronomers were so important to cernus they gave him his motivation he's the first European to share iel Ham's deep aversion to Tommy's cosmology and that's what makes cernus not the first great astronomer of a new European tradition but the last of the Islamic tradition this is the second edition as we've seen many of the complex mathematical models cernus uses in his new heliocentric model like the tusi couple are copied from Islamic astronomers but more importantly it's cernus is deep desire to bring mathematical consistency to cosmology that he really owes to his Islamic predecessors Cernic's ideas set in motion a train of scientific Revelations that would eventually lead to Isaac Newton and the discovery of gravity in Newton's hands iel haan's dream of an astronomy with rigorous and coherent mathematics which agrees with experimental observation finally took place but this begs two crucial questions why was the Great astronomical project which Islamic astronomist began completed in Europe and not in the Middle East and how did knowledge of Islamic science get to Europe in the first place the answers to these questions lie in one of the most beautiful cities on Earth the queen of the Adriatic [Music] Venice Venice was founded on a swamp off the coast of Italy and felt itself separate from Europe and not bound by its laws and traditions and as Shakespeare famously pointed out the two most important aspects of Venice were its merchants and its long-standing links with the Arabs or Moors it was a rich and complicated relationship sometimes based on piracy and theft The Story Goes that in 828 two Venetian Merchants stole the bones of a famous Christian saint from venice's rival city across the water Alexandria the bones belong to St Mark the Evangelist and they brought them back here to St Mark square but without doubt trade with the East brought to Venice great wealth and an exchange of ideas customs and people as Venice expert Vera costantini showed me so this is called campi because as you can see at the corners there are statues of what were called Moors oh there's another yeah there's another one with a turban the beard was recommended to Venetian Merchants even when they went to the east there was there were manuals written for for Venetian Merchants how to blend in how to yes you know how to be respected in this yeah as venetians traded more and war with their Muslim neighbors the influence of Islam was more strongly felt Arabic Coffee Culture became hugely popular as did Islamic styles of architecture with their characteristic arches and decorations so the next thing I want to show you is the Palace of the camel and when venetians traded in the East the of measurement of a load that could be loaded on a drry was called carico and it was the exactly same Unity of measurement they had in the East and it was called UK so it's not coincidence that they no it's not they actually imported that unit of weight yes of measurement yeah of weight and with the Arabic trade came the Arabic books the great 9th century Arabic text on algebra appeared in Latin in the 12th century the same Century saw the arrival of Arabic astronomical tables and in the 15th century the famous Cannon of medicine was first published in the [Music] west and this influx of learning seems to coincide with a great historical shift the engine of science begins to move west from the Islamic world to Europe that's where the great breakthroughs from the 1500s would mainly take place I encountered an astonishing and very tangible symbol of this shift and a really surprising clue as to why it happened thanks to Professor Angela noovo from the University of [Music] UD 20 years ago in this library on one of the islands of Venice Angela discovered the only surviving version of a 500y old book and what did it feel like I mean this is this is a big Discovery yes it was a great emotion I remember it was July very hot like today even hotter and I felt cold wow that moment yes and yes it was a great emotion what she found was the very first printed copy of Islam's holy book the Quran now they ask you this is the first time she's seen her Quran since she discovered it 20 years ago it was but it struck me as strange that the world's first printed Quran was produced in Venice and not in the Islamic world and it's obvious at first glance that it was printed by people who didn't speak Arabic very well it's yeah I mean what strikes me is that it's it's written in in what I would regard as almost childlike handwriting it's clumsy yeah yeah well it's the first attempt to reproduce the handwriting in movable types and as you know the language has an enormous amount of sorts different sorts as of course every letter changes according to ligatures and the position of course in the the worda which means for that you the dash should be underneath the L here but it's above it so instead of saying Thea it saysa which is which is wrong probably there were not people really of mother language in the Press so there were some errors of the mistakes in the text which are of course things yes of course I mean as as as the Quran for every Muslim believes it's this word of God you can't so when you change it it's a sin it's yes how was it first received do you think when it was published well yes the idea is that the hypothesis is and I think it's true that it was an enormous failure from really the business point of view as uh the Muslim didn't accept the printing press for centuries and probably the whole copies of this book were destroyed so we don't have any other copy the only probably the only one that remained in the western world is this book I felt that the failure of this printed Quran to catch on in the Islamic World spoke [Music] volumes 800 years earlier one reason for Islamic science's success had been the Precision of the Arabic language with over 70 different ways of writing its letters and many extra symbols to Define pronunciation and meaning it allowed Scholars of many different lands to communicate in a single common language now with the arrival of the printing press scientific ideas should have been able to travel even more freely in the west books printed in Latin accelerated its scientific Renaissance but because of its symbols and extra letters Arabic was much harder to set into type than Latin and so a similar acceleration in the Islamic World failed to materialize I believe this rejection of the new technology the printing press marks the moment in history when Arabic science undergo a seismic shift Europe has embraced Greek and Arabic knowledge and the new technology and Galileo and his ilk are poised at the cusp of the Renaissance it has been a turning point both in the history of the Venetian printing press who used to be extremely powerful I mean it's the limit of expansion let's say and in the history of the relationship the cultural and general relationship between the East and the West as acceptation of printing would have meant the acceptation of the first important technology so you know the two histories started to differ very much as you know this initial rejection of Prince was one of the many reasons that caused science in the Islamic world to fall behind the West it coincided with a host of global changes all of which affected the way science developed the first and most obvious reason for the slowdown in Islamic science is that the Islamic empire itself falls into to decline from the mid 1200s one reason for this is that it's under attack from all sides from the east of the Mongols in 1258 they invaded the capital Baghdad and it said that the Waters of the tigress and Euphrates rivers ran black for days with the ink of the books they' destroyed but trouble was also brewing in the far west of the Empire Islamic Spain already fragmented into separate city states now faced a new threat a United and determined Onslaught from the Christian North the reconquest as it was called raged for hundreds of years but culminated in the 15th century when Ferdinand II and Isabella LED an army which forced the last of the Muslims in Granada to surrender in 1492 the Christians were intent on removing every last vesage of Islamic civilization and culture from Spain in 1499 they ordered the burning in this Square in Granada of all Arabic texts from Granada's libraries except for a small number of medical texts within about a 100 years every Muslim in Spain had either been put to the sword burnt at the stake or banished and Christians from the east of Europe were intent on reclaiming the Holy Land the Crusades bent on carving out a holy Christian Levant and claiming the holy city of Jerusalem the Crusaders launched a massive attack on Northern Syria they quickly captured this castle and turned it into one of their strongholds s then with ruthless and missionary Zeal they marched on Jerusalem and as the Empire fought with its neighbors it collapsed into Waring foms the mamluks slaves who originally belonged to the state of Egypt became its leaders the bourbon alads ruled Morocco and Spain in the 13th century and the north of Syria and Iraq splintered into a series of city states but for many historians of science the biggest single reason for the decline in Islamic science was a rather famous event that took place in 1492 that year the entire political geography of the world changed dramatically when a certain Christopher Columbus arrived in the Americas I explain it with the phenomena of the discovery of the new world in for 1892 the immediate result is that you got immense amount of gold and silver coming to the Royal houses of Europe at the time and all the adventurous Empires and Royal houses of the time were setting colonies all over the world and science always follows the money as the 16th and 17th centuries came and went that money power and hence scientific will moved through Spain and Italy and on to Britain by the 17th Century England sitting at the center of the lucrative Atlantic trade route could afford big science and that ultimately explains why the greatest book in World science Sir Isaac Newton's prinkipia Mathematica the book that ultimately explains the motion of the Sun the moon and the planets was not published in Baghdad but in London it was necessary for him to have data of astonishing accuracy gathered from a across the world global inventories of numbers observations positions the heights of Tides the positions of comets and planets uh the rate at which pendulums beat it's a global project it's big science and many of those observations many of those mathematical models were of course models initially developed by Islamic astronomers in Egypt and the near East and Central Asia but there's a final twist in the tale as the wealth of the Islamic Nations subsided through War political and religious entrenchment and the loss of its lucrative trade so its science declined but what this doesn't explain is why their scientific achievements have been so forgotten and that's partly because as Europeans colonized great SES of the Middle Eastern Asia they actively encouraged the idea that the civilizations they encountered were moribond and in Decline it seems the English and the French were uncomfortable with subjugating people whose knowledge and science may have been as sophisticated as their own so it became important to portray the Islamic World in a very specific way namely that yes they once were very sophisticated and they had great scientists and philosophers but of course now they fallen into Decay somehow this point of view made the whole Colonial Enterprise seem much more palatable one of the most fascinating developments I think in the history of the encounter between Western Europeans and other cultures is a kind of shift which has got got fundamental and terrible consequences amongst Western Europeans when they start to reflect on why they are superior it doesn't often cross Western Europeans Minds that they might not be superior to everybody else for a very long time after all Western Europeans in general the British for example suppose that their superiority lay in their religion but then I think around the 7 1900s we begin to see a shift and the shift is from claiming that the reason for European superiority is its religion to the reason for European superiority is its Science and Technology it eventually it ends up with the famous phrase we have the Gatling gun and they do not Europeans and that period were quite prepared to acknowledge that in ancient times Islam for example had achieved great things in the Sciences but they weren't doing so now so even recent Islamic and Sanskrit astronomy was imagined to be very old because if it was very old it meant that the culture the British were conquering was declining and for the British that was clearly good news and some experts believe that the effect of this on Islamic scientific history is still felt in the Islamic world today the Islamic part and the Arab part have not yet discovered their history because their history was obliterated intentionally by the colonization period and unfortunately when they ReDiscover it now they're rediscovering it in bits and [Music] pieces so today for many different reasons the great observatories of the medieval Islamic world are ruined husks and it's true to say that most of the great scientific breakthroughs of the last four centuries have taken place in the west but that's not to say that science has completely ground to a halt in the Islamic world now in the 21st century there are many examples of cuttingedge research being carried out well I've arrived at The royan Institute here in ter Iran where they carry out stem cell research uh infertility treatment and cloning research I was surprised to learn that here in Iran an Islamic State potentially controversial science like genetic modification and cloning is condoned even funded by a Theocratic government one of the uses is when a small part of the heart stops working which is finally going to lead to Heart failure right so the cells from that part of the heart are actually replaced with the cells that have been cloned another use of cloning and Therapeutics is actually creating an animal which has the medicine in their milk for example so when we drink the milk we actually receive the medicine we need considering genetic research has many vifer opponents in Christian communities I was intrigued to see that here in tan they have their own inhouse Imam to offer support and advice on this sometimes quite controversial research we have got uh this medical ethic committee here in Ruan Institute and every project which is proposed is uh investigated in this committee and we see different aspects of it and they have got to justify the project for us I'm not enough of an expert in genetics to truly assess the quality of the work here but one thing I can say is how at home I felt whatever cultural and political differences we have with the Iranian State inside the walls of the lab it was remarkably easy to find common ground with fellow scientists Nature's rules are refreshingly free of human Prejudice that's something the scientists of the medieval Islamic World understood and articulated so well in the 9th century alisi synthesized Greek and Indian ideas to create a new kind of Mathematics Algebra the polymath iban Cena brought together the world's traditions of healthare into one book contributing to the creation of the subject of Medicine in remote Iranian mountains astronomers like elori paved the way for scientists working hundreds of years later in Western Europe these scientists Quest For Truth wherever it came from was summed up by the 9th century philosopher El Ki who said it is fitting for us not to be ashamed of acknowledging truth and to assimilate it from whatever Source it comes to us there is nothing of higher value than truth itself it never cheapens or abases he who [Music] seeks one moral emerges from this epic tale of the rise and fall of Science in the Islamic World between the 9th and 15th centuries and that is that science is the universal language of the human race decimal numbers are just as useful in India as they are in Spain Star Charts drawn up in Iran speak volumes to astronomers in northern Europe and Newton's pipia is just as true in Arabic as it is in Latin or English what medieval Islamic scientists realized and articulated so brilliantly is that science is the common language of the human race man-made laws may vary from place to place but nature's laws are true for all of us [Music] that was the last in the series next tonight how to fit a square peg into a round hole if only it were that simple it's hole in the wall next [Music]