Pathfinders: The Golden Age of Arabic Science

The Muslim Empire became a major player on the stage of world politics over an astoundingly short period of time - between the middle of the 7th century AD, when Islam began in the desert cities of Arabia, and the middle of the 8th century AD, by which time it dominated a realm extending from Spain in the West to Central Asia in the East. Equally astounding was the culture that it nurtured. In Baghdad in the early 9th century, for example, the Caliph al-Ma'mun ordered the construction of an astronomical observatory to test the accuracy of data inherited from Greek sources that had been translated into Arabic during the previous decades.

This enterprise was in fact "the world's first state-funded large-scale science project", as Jim Al-Khalili puts it in Pathfinders: The Golden Age of Arabic Science. But the caliph did not stop there, for he also instigated programmes in which groups of scholars and instrument-makers were assembled to address other scientific issues: to determine as accurately as possible the length of a one-degree arc on the Earth's curvature (and with that, the circumference of the Earth, which was known to be spherical), and how to more accurately calculate the coordinates of major world cities and landmarks. At the same time, in Baghdad, the foundations were being laid for the development of algebra and the adoption of the decimal system of notation.

Such remarkable historical facts have been available to the general English reader in various formats for some time (despite the implication in the preface to this book). Never, however, has such material been assembled in as compelling a manner. Al-Khalili, who was born in Iraq and spent his early years there, has interwoven the story of pre-modern science in the Middle East with his own family history - as interesting in its own right as the historical tale he has to tell. The resulting volume is composed in a lively writing style, with occasional ironic asides or references to modern parallels and even puzzles to help readers understand the procedures that were used at the time.

The period he writes about was one in which Arabic was the language of learning, commerce and politics - as Latin was to become for many centuries in Europe. It was a heady and exciting intellectual climate in which scholars and scientists moved from one centre of court patronage to another as political regimes came and went over 500 years. The multicultural and multilingual society of Baghdad (and later Damascus, Cairo and other localities) reverberated with an intellectual vitality comparable to that of Athens some 12 centuries earlier, or Florence in the 15th century.

Al-Khalili approaches the subject from a modern perspective - that of a research physicist and an avowed atheist. For this reason, he insists upon the complete separation of science from religion. The result is a certain cherry-picking of the best ideas as defined by our modern notion of correctness and truth. This approach also distorts the attitudes towards science at the time he is writing about, for virtually no scholar or "scientist" of that day would have accepted such a dichotomy between religion and science. At the very least, they would have adhered to the Arabic maxim cited in medieval texts: "Whoever does not know astronomy and anatomy is deficient in the knowledge of God."

His astonishment and enthusiasm is palpable as he writes of the sophisticated scientific ideas explored by Arabic-speaking thinkers of these early centuries. In his understandable desire to make his points, there are inevitable overstatements. Earlier societies such as ancient Greece also engaged in close observation, the recording of data and even "experiments" such as comparative anatomical dissection, although a casual reader of this book might be left with the impression that such approaches were unique to medieval Arabic scholars.

Terms such as "experimentation", "controlled experiments", "clinical trial", "control group", "experimental method" and "scientific method" are left largely undefined and are tossed about in a surprisingly loose manner for a scientist. On occasion they are applied in inappropriate ways, such as calling an "experiment" the determination of the circumference of the Earth by measuring the height of a mountain - a calculation undertaken by the highly inventive al-Biruni (or Alberonius, as he was known in Latin), who died in 1048. There are also occasional small factual mistakes, but nothing serious enough to confuse or mislead the reader.

The same cannot be said for the illustrations, for the volume is marred by their poor choice and lack of integration. Except for those of the Al-Khalili family, the plates appear to have been assembled at the last minute by a picture researcher. Ten plates are never referred to in the text itself, including one providing a diagram of a solar eclipse from a treatise attributed to al-Karaji, who is never mentioned in the course of the book (although the same illustration is used on the dust jacket). The reader is referred to Plate 15 for an illustration of a lunar crater named after the legendary Andalusian inventor Abbas ibn Firnas, only to find an illustration of the muscles of the eye from a 9th-century ophthalmological treatise.

Readers directed to Plate 19 for an illustration of surgical instruments originally drawn by the Andalusian physician al-Zahrawi, who worked around the year 1000, will be surprised to find a map of northern Iraq from a treatise on geography composed in the 10th century (not the 11th, as stated in the caption). Even the two modern maps intended to assist the reader are confusing, for the boundary lines between realms are unclear and the River Ebro has lost a letter between the two versions. Most important, some of the locations mentioned frequently in the text, such as Khurasan, appear on neither map. For a work intended for the general public, this is unhelpful.

Setting aside these weaknesses, however, this highly readable volume has much to offer. Al-Khalili has made a conscious effort not to be unduly biased towards the scholars of Islam and thereby downplay the activities of other early societies, such as Greece (he mostly succeeds). Throughout he presents a fair and balanced evaluation of the quite remarkable achievements of Arabic-speaking scientists over 700 years. For example, he neatly explains why so much credit is due to al-Khwarizmi, a highly original scholar of 9th-century Baghdad, for the development of algebra (and not simply because the word "algebra" derives from the title of his treatise).

He presents an excellent summary of the contentious issue among historians today of the possible influence on Copernicus of mathematical models developed by Muslim astronomers. Al-Khalili also gives proper attention to the extraordinary role of paper production in the diffusion of new ideas and its impact on all aspects of life at the time, somewhat parallel to the computer's role today in transforming access to information. More could have been said in the volume about other technological advances during this period, and the author would have benefited from employing the writings of Donald Hill on the topic.

As it stands, the volume is an enjoyable and highly useful introduction to a society of creative thinkers and our intellectual forebears. Equipped with razor-sharp intellects, they challenged scientific authority, developed instruments allowing for the greatest possible precision prior to the telescope or microscope, and refined mathematical models to account for better observational data. The intellectual creativity of these early scholars is impressive, but Al-Khalili provides no suggestions for further reading. That is a pity, for this engaging book should be the beginning - not the end - of learning about an overlooked but fundamental part of our scientific heritage.

THE AUTHOR

When he moved to the UK from Iraq as a teenager, not only did Jameel (Jim) Al-Khalili's love of science flourish, but he also became a supporter of Leeds United Football Club. Those two passions have endured: a keen Sunday-league footballer until he sustained a knee injury in his late twenties, the theoretical physicist is one of 21 "Faces of UK Science" on permanent display at the National Portrait Gallery in London.

Graduating with a BSc in physics from the University of Surrey, he stayed on to pursue a PhD in nuclear-reaction theory and was later awarded professorships in physics and public engagement in science at the institution.

He was awarded the Royal Society's Michael Faraday Prize for science communication in 2007, and is the author of four popular science books, covering topics including black holes and quantum physics.

A frequent guest on television and radio who readily admits that he loves performing, Al-Khalili still finds time for hobbies as diverse as oil painting and card tricks. He recently revealed on BBC Radio 4's Desert Island Discs that his luxury item would be his acoustic guitar.

Chloe Darracott-Cankovic.