Pathfinders

by Jim Al-Khalili

  Given how far back it stretches in time, the history of the region – and even of Iraq itself – is too big a canvas for me to paint. Instead, what I hope to do in this book is take on the nonetheless ambitious task of sharing with you a remarkable story; one of an age in which great geniuses pushed the frontiers of knowledge forward to such an extent that their work shaped civilizations to this day.

  I have for some time had the strong desire to bring this story to a wider audience. That I do so now lies in my belief that it has never been more timely, nor more resonant, to explore the extent to which Western cultural and scientific thought is indebted to the work, a thousand years ago, of Arab and Persian, Muslim, Christian and Jewish thinkers and scientists. Popular accounts of the history of science typically show a timeline in which no major scientific advances seem to have taken place during the period between the ancient Greeks and the European Renaissance. In between, so we are told, Western Europe and, by extrapolation, the rest of the world, languished in the Dark Ages for a thousand years.

  In fact, for a period stretching over seven hundred years, the international language of science was Arabic. For this was the language of the Qur’an, the holy book of Islam, and thus the official language of the vast Islamic Empire that, by the early eighth century CE, stretched from India to Spain.

  I must also stress at the outset that my task is not to cover the whole of the history of science around the globe. I am well aware of the richness and variety of scientific achievements in other parts of the world, particularly in China and India, and there have been many books written – and no doubt many more yet to be written – about these two glorious civilizations. But that is not my story.

  I have been helped tremendously in my task of exploring the subject through the making of a recent BBC television series, Science and Islam. But unlike in the series, I have had the luxury in this book of exploring in more depth both the science and its associated social, political and historical influences and implications. Of course, the extensive travelling I undertook around the Islamic world in the making of the series was useful in two ways. First, and probably most importantly, it brought the subject alive for me in a way that the many books and scholarly articles I have buried myself in could not do. Secondly, it provided me with an opportunity to meet and discuss ideas with many scholars and historians from a wide range of backgrounds. I hope this book does them justice too.

  Naturally, there will be those who might suspect that, having grown up in Iraq, I see the Muslim world through rose-tinted glasses, a biased partisan on a mission to demonstrate what a wonderful and enlightened religion Islam is. However, as an atheist my interest in Islam is cultural rather than spiritual. So if Islam as a belief system, unencumbered by the misconceptions and misinterpretations of many of today’s Muslims and non-Muslims alike, comes out of my account in a positive light, then so be it.

  There is no doubt that, to the ear of many non-Muslims around the world today, the term ‘Islam’ too comfortably evokes a negative stereotype that contrasts with our Western secular, rational, tolerant and enlightened society. This lazy view can make it difficult to acknowledge that a thousand years ago the roles were reversed. Think of the Crusades: which side back then was the more enlightened, the civilized, the ‘good guys’? Even those in the West who have a vague awareness of the contribution of the Muslim world to science tend to think of it as no more than a reheating of Greek science and philosophy with the odd bit of originality subtly added, like Eastern spice, to enhance the flavour. A grateful Europe then eagerly reclaimed its heritage once it awoke from its slumber during the Renaissance of the fourteenth and fifteenth centuries.

  I shall address many questions that have long intrigued scholars of the history of science. How much science, for instance, did the Arabs actually know? How important were the contributions of Persian culture, Greek philosophy and Indian mathematics? How and why did scientific scholarship flourish under the patronage of certain rulers? And, possibly most interestingly, why and when did this golden era come to an end?

  As a practising scientist and a humanist, I believe that what is referred to as the ‘scientific method’, and the knowledge that humanity has gained from rational science, gives us far more than just ‘one way of viewing the world’. Progress, through reason and rationality, is by definition a good thing; knowledge and enlightenment are always better than ignorance. Growing up in Iraq, I learnt at school about such great thinkers as Ibn Sīna (Avicenna), al-Kindi and Ibn al-Haytham (Alhazen), not as remote figures in history but as my intellectual ancestors. Many in the West will have heard, for instance, of the Persian scholar Ibn Sīna. But there are very many other great names that have been largely forgotten. Even in Iraq, I encountered these characters not in science classes but in history lessons. For the teaching of science in the Muslim world today follows the Western narrative. While it is not surprising that European children are taught that Copernicus, Galileo and Kepler were the fathers of astronomy, that nothing of note came before them, it is rather more disappointing that children in the Muslim world are taught the same thing. Might they not sit up and take notice if they were told that most of the stars we see in the night sky have Arabic names? For instance, the names of five of the seven main stars that make up the constellation Ursa Major (or ‘Great Bear’) – also known as the Big Dipper or the Plough – are Arabic in origin: Dubhe, Megrez, Alioth, Mizar and Alkaid.

  The scientists who feature in this book truly were pathfinders, both literally and metaphorically. The title of the book is taken from a quotation about the fourteenth-century scholar Ibn khaldūn, but is in fact applicable to all those whose stories and achievements I touch upon. For they all broke new ground in advancing mankind’s knowledge, yet most have been forgotten.

  The transmission of science, especially that of mathematics and astronomy (referred to by historians as the ‘exact’ sciences), is one of the most powerful tools for establishing relationships between different civilizations. Other areas of human thought – such as religion and philosophy – are transferred more slowly and will only gradually diffuse into, and influence, a particular culture. But the exact sciences require the direct use of treatises and other written work and so can tell us a great deal about the circumstances of the time. And while my motives for trying to piece together a complete picture of Arabic science are no different from those of a historian, I should stress that my primary interest is in the origin and development of the science itself. For this reason, it does not really concern me whether the science in question was developed by Greeks, Christians, Muslims or Jews. And while I devote a chapter to examining how the Islamic Empire inherited the science of the Greeks and other civilizations, I nevertheless wish in this book to explore the ideas themselves, in the fields of natural science, medicine, philosophy and mathematics, which emerged and matured during medieval Islam.

  For a theoretical physicist more familiar with the inner workings of the atomic nucleus, this has been an exhilarating and refreshing journey. I am particularly pleased therefore to have turned over many stones that others before have either ignored or had not seen fit to describe to a wider audience.

  This book has been three years in the writing, throughout which time I have been on a relentlessly steep, yet hugely enjoyable, learning curve. I have been helped enormously in my research and education by many people; some are experts on the subject of Arabic science, others have provided insightful comments and helpful advice. Each one of them has added to this book and helped me turn it into something I am immensely proud of. First and foremost, I thank my wife Julie for her constant encouragement and companionship. I also owe a huge debt of gratitude to my agent Patrick Walsh, and commissioning editor at Penguin Press, Will Goodlad, both of whom have shared my enthusiasm for the subject and helped me mould my initial clunky, diffident and tentative draft into a more assured final product that I hope is both accurate and readable. I would also like to thank Afifi al-Akiti, Ali al-Azzawi, Nader a
l-Bizri, Salim al-Hassani, Faris Al-Khalili, Salima Amer, Amund Bjørnøs, Derek Bolton, Paul Braterman, Anna Croft, Misbah Deen, Okasha El Daly, Kathryn Harkup, Ehsan Masood, Peter Pormann, George Saliba, Mohammed Sanduk, Simon Schaffer, Andrea Sella, Paul Sen, Karim Shah, Adel Sharif, Ian Stewart, Rim Turkmani, Tim Usborne and Bernardo Wolf. I am hugely grateful to them all.

  A Note on Names, Pronunciations, Spellings and Dates

  It is common for English speakers to mispronounce Arabic names – not because some of the guttural-sounding letters have no English counterpart, but because the wrong syllables are often stressed. For instance, the Iraqi city of Kerballa was often mispronounced by news reporters during the Iraq invasion in 2003 as Kerballa or Kerbellah rather than the correct Kerballa. To transcribe Arabic words in English correctly, diacritical symbols should be added above or below letters to give them the correct pronunciation. However, I have not been overly pedantic or rigorous on this front, and have instead aimed at a ‘halfway house’ convention that closely approximates to the correct vowel sounds without worrying too much about the more awkward consonants. Therefore, you will find many names with a macron over a vowel to extend its sound. For instance, the Persian scholar Ibn Sīna is phonetically pronounced ibin seena. Without the macron over the ‘i’, Sina would more likely be pronounced by a native English speaker as sinner, which would be wrong. For Arabic words familiar in English I dispense with all diacritical marks. Thus, I do not bother to write Baghdād, Islām, Qur’ān or Irāq (provided the ‘a’ in Iraq is understood to sound like it does in ‘car’ rather than ‘cat’). Even for less familiar words, if I can get away without a diacritic then I will. Thus, the Arabic for ‘book’, kitab, should be written as kitāb, but since it is natural for a native English speaker to pronounce it correctly anyway, with a short ‘i’ and longer ‘a’ (kitab) then the bar is deemed unnecessary.

  In scholarly works, historians often insist on a comprehensive transcription of Arabic words into English with additional diacritics, such as dots underneath consonants. But I feel no obligation to follow this convention closely. Let me give you an example of what I mean: a famous text by the eleventh-century scholar Ibn al-Haytham, translated as ‘The Book of Optics’, is traditionally transcribed as Kitab al-Manazir. But the ‘z’ should really be written with a dot underneath it, ẓ, denoting the Arabic letter . The correct way to pronounce this letter is like the hard ‘th’ in ‘the’ (and not soft as in ‘think’), but with the tongue protruding further outside the mouth, which is more rounded. So, for me, a more faithful and closer pronunciation would be to spell the word as ‘al-Manathir’. The only reason to use a ‘z’ is if the word were pronounced in the colloquial style of certain Arab countries today, such as Egypt. So, my decision not to use any diacritical marks with consonants means I sometimes stray from the conventional scholarly transliteration and focus on a more natural transcription that is closer to the correct classical Arabic.

  In some cases, I have deferred to tradition. Thus, the word ‘ibn’ (‘son of’) is really pronounced ibin but it is usual not to include the second ‘i’ in the spelling; in any case it is difficult not to include a vowel sound between the ‘b’ and the ‘n’. Likewise, the name al-Khwārizmi – a mathematician we shall meet later – is always spelt this way, but the more accurate Arabic, and Persian, pronunciation is to include a vowel (an ‘a’ or an ‘o’) after the ‘Kh’.

  In a break with popular Western tradition on this subject, I believe there is no excuse not to refer to people by their correct Arabic or Persian names rather than the Latin derivation that has been passed on to us. Thus, I refer to Ibn Sīna and Ibn Rushd rather than the better known, in the West, Avicenna and Averroës. Finally, most Persian scholars have Arabized names with the definite article ‘al’ placed in front of the name. Thus al-Bīrūni and al-Tūsi would simply be Bīrūni and Tūsi in Persian. I have, however, stuck with the more familiar (usually Arabic) version of their names and hope that Iranian readers are not too offended. Thus, while I keep the more familiar Persian name of the mathematician Omar Khayyām, another Persian, Khwarizmi, is better known by the Arabized al-Khwārizmi.

  Many of the characters we shall encounter have impressively long names that involve not only their forenames and family names but, sandwiched in between, the names of their fathers and grandfathers. They may also pick up a laqab (nickname) or nisba, based on an attribute of their personality, profession or origin, such as describing someone from Baghdad as ‘al-Baghdadi’. They can even be known by the name of their eldest son. Thus the word Abū (pronounced aboo) means ‘father of’. If a man does not have children then his first name is often associated with a prominent character in Arabic or Islamic history who would have had a son. Among many Shi’ite Muslims, the name Ali is always associated with that of Imam Ali and his son, Hussein. Thus, when a man is referred to as Abū Hussein, he may either have an eldest son named Hussein or may simply be an Ali with no sons.

  For example, the mathematician al-Khwārizmi has the full name Abū Abdullah Muhammad ibn Mūsa al-Khwārizmi, which means his first name is Muhammad but his son is Abdullah and his father’s name is Mūsa (Moses). Sometimes he is referred to as Muhammad ibn Mūsa, but is far better known as al-Khwārizmi, named after his birthplace Khwārizm (modern Khiva in Central Asia).

  The common language used universally across the Arab world is referred to as classical Arabic. This is the Arabic of the Qur’an, and the Arabic of the educated classes. However, Arabic dialects differ widely from one country to the next and certain letters are pronounced differently. Thus a ‘j’ in Iraq is pronounced the same as in English, whereas in Syria it would be pronounced as in the French bonjour and in Egypt as a ‘g’ sound. But more than just accents differentiate Arabic dialects. Often words are completely different. For instance, in Iraq, the word for ‘yes’ is ee; in Egypt, it is aywa, but in classical Arabic, it is na’am. I mention this because classical Arabic, being the language of the Qur’an, has not changed at all in fourteen centuries, making the writings of the early Islamic scholars as accessible today as they were then.

  On the issue of dates, there are several standard conventions, and I have chosen the one most commonly used by contemporary historians. Apart from the early chapters, when I cover the sciences of antiquity and have to use the ‘BCE’ notation (Before the Common Era, or Before the Christian Era), years not so identified should be taken to denote the Common Era (or Christian Era), CE. For brevity, I have chosen not to include Muslim Hijri dates – the calendar that began in 622 CE.

  A Note on the Term ‘Arabic Science’

  Throughout the book, I use the term ‘Arabic science’ in its broadest sense. I do not mean by this only the science practised by people of Arab blood, and therefore carefully refrain from referring to it as ‘Arab science’. That would necessarily constrain the discussion to the inhabitants of Arabia (modern Saudi Arabia and southern Syria and Mesopotamia) many of whom, outside the cities, were in any case simple Bedouin desert tribes. What I mean by ‘Arabic science’ is that carried out by those who were politically under the rule of the Abbāsids, whose official language was Arabic, or who felt obliged to write their scientific texts in Arabic, the lingua franca of science in the medieval world. A large part of the scientific body of work was initially (in the ninth and tenth centuries) carried out in today’s Iraq, in the cities of Basra, Kūfa and, most importantly, Baghdad.

  Many of the scientific figures we shall encounter along our journey, such as al-Bīrūni and Ibn Sīna, were Persians, and were often even anti-Arab in their sentiments. But what matters in this context is that most of their scientific work was written in Arabic, not Persian. Nor indeed do we find that all the scientific work was carried out by Muslims, despite the undeniable fact that this explosion in scientific creativity would not have been possible without the spread of Islam, as I shall explain later on. Many important contributions were made by Christians and Jews, particularly in the early days of the Abbāsid era when the
main body of translation from Greek texts was being carried out. But even they shared with their Muslim rulers a common culture that encompassed their customs, thinking, education and language.

  Thus, when I speak of ‘Arabic’ scientists I do not mean the word in the sense that they had to have been born and educated in today’s Arab and Arabic-speaking countries and would have regarded themselves as Arabs, rather that it was the Arabic language that united them. I therefore include the great Persian scientists as part of this broad definition.

  A nice example to emphasize this point is that of the Alexandrian astronomer Ptolemy, author of the Almagest (c. 150 CE), one of the most important astronomical texts ever written. Those who would question whether the work of Persians such as al-Bīrūni and Ibn Sīna is rightly part of Arabic science cannot then class the work of an Egyptian such as Ptolemy as part of Greek science. However, it is acknowledged universally that Ptolemy’s work was no less a part of the science of the Greeks than that of Euclid, Archimedes or Aristotle.

  Naturally, you might ask whether it is not more appropriate to define this as Islamic, rather than Arabic, science. There are three reasons why I have not done so. The first is one that I have alluded to already: not all the important scientific advances were carried out by Muslims. Before the spread of Islam in the seventh century, much of the Middle East was Christian. Its two main sects were the Nestorians (chiefly in the cities of Hīra in southern Iraq and Edessa and Antioch in northern Syria) and the Monophysites (who were spread throughout Syria, Anatolia and Egypt). In addition, large parts of the region before Islam also practised the ancient Mazdean and Zoroastrian religions, even Buddhism. Consequently, during the golden age of Arabic science many of the leading figures were not Muslims. The greatest of all the translators of Baghdad, Hunayn ibn Ishāq, was a Nestorian who never converted to Islam. Other Christian scientists of ninth-century Baghdad include the astronomer Yahya ibn abi Mansūr and the physicians Jibrīl ibn Bakhtyashū and Ibn Massāwayh. Likewise, many Jewish philosophers and scientists, such as the translator Sahl al-Tabari, the medic Ishāq ibn Amrān and the astronomer Mashā’allah, all made valuable contributions to the intellectual culture of Baghdad. Nor can we ignore the many contributions of the Andalusian Jewish scholars between the eighth and eleventh centuries, or even later, such as the great medieval Jewish philosopher and physician Maimonides, who was born in Córdoba but spent much of his life in Egypt.