Not only has secularism failed to continue its steady global march but countries as varied as Iran, India, Israel, Algeria and Turkey have either had their secular governments replaced by religious ones, or have seen the rise of influential religious nationalist movements. Secularisation, as predicted by the social sciences, has failed.

To be sure, this failure is not unqualified. Many Western countries continue to witness decline in religious belief and practice. The most recent census data released in Australia, for example, shows that 30 per cent of the population identify as having ‘no religion’, and that this percentage is increasing. International surveys confirm comparatively low levels of religious commitment in western Europe and Australasia. Even the United States, a long-time source of embarrassment for the secularisation thesis, has seen a rise in unbelief. The percentage of atheists in the US now sits at an all-time high (if ‘high’ is the right word) of around 3 per cent. Yet, for all that, globally, the total number of people who consider themselves to be religious remains high, and demographic trends suggest that the overall pattern for the immediate future will be one of religious growth. But this isn’t the only failure of the secularisation thesis.

Scientists, intellectuals and social scientists expected that the spread of modern science would drive secularisation – that science would be a secularising force. But that simply hasn’t been the case. If we look at those societies where religion remains vibrant, their key common features are less to do with science, and more to do with feelings of existential security and protection from some of the basic uncertainties of life in the form of public goods. A social safety net might be correlated with scientific advances but only loosely, and again the case of the US is instructive. The US is arguably the most scientifically and technologically advanced society in the world, and yet at the same time the most religious of Western societies. As the British sociologist David Martin concluded in The Future of Christianity (2011): ‘There is no consistent relation between the degree of scientific advance and a reduced profile of religious influence, belief and practice.’

The story of science and secularisation becomes even more intriguing when we consider those societies that have witnessed significant reactions against secularist agendas. India’s first prime minister Jawaharlal Nehru championed secular and scientific ideals, and enlisted scientific education in the project of modernisation. Nehru was confident that Hindu visions of a Vedic past and Muslim dreams of an Islamic theocracy would both succumb to the inexorable historical march of secularisation. ‘There is only one-way traffic in Time,’ he declared. But as the subsequent rise of Hindu and Islamic fundamentalism adequately attests, Nehru was wrong. Moreover, the association of science with a secularising agenda has backfired, with science becoming a collateral casualty of resistance to secularism.

Turkey provides an even more revealing case. Like most pioneering nationalists, Mustafa Kemal Atatürk, the founder of the Turkish republic, was a committed secularist. Atatürk believed that science was destined to displace religion. In order to make sure that Turkey was on the right side of history, he gave science, in particular evolutionary biology, a central place in the state education system of the fledgling Turkish republic. As a result, evolution came to be associated with Atatürk’s entire political programme, including secularism. Islamist parties in Turkey, seeking to counter the secularist ideals of the nation’s founders, have also attacked the teaching of evolution. For them, evolution is associated with secular materialism. This sentiment culminated in the decision this June to remove the teaching of evolution from the high-school classroom. Again, science has become a victim of guilt by association.

The US represents a different cultural context, where it might seem that the key issue is a conflict between literal readings of Genesis and key features of evolutionary history. But in fact, much of the creationist discourse centres on moral values. In the US case too, we see anti-evolutionism motivated at least in part by the assumption that evolutionary theory is a stalking horse for secular materialism and its attendant moral commitments. As in India and Turkey, secularism is actually hurting science.

In brief, global secularisation is not inevitable and, when it does happen, it is not caused by science. Further, when the attempt is made to use science to advance secularism, the results can damage science. The thesis that ‘science causes secularisation’ simply fails the empirical test, and enlisting science as an instrument of secularisation turns out to be poor strategy. The science and secularism pairing is so awkward that it raises the question: why did anyone think otherwise?

Historically, two related sources advanced the idea that science would displace religion. First, 19th-century progressivist conceptions of history, particularly associated with the French philosopher Auguste Comte, held to a theory of history in which societies pass through three stages – religious, metaphysical and scientific (or ‘positive’). Comte coined the term ‘sociology’ and he wanted to diminish the social influence of religion and replace it with a new science of society. Comte’s influence extended to the ‘young Turks’ and Atatürk.

The 19th century also witnessed the inception of the ‘conflict model’ of science and religion. This was the view that history can be understood in terms of a ‘conflict between two epochs in the evolution of human thought – the theological and the scientific’. This description comes from Andrew Dickson White’s influential A History of the Warfare of Science with Theology in Christendom (1896), the title of which nicely encapsulates its author’s general theory. White’s work, as well as John William Draper’s earlier History of the Conflict Between Religion and Science (1874), firmly established the conflict thesis as the default way of thinking about the historical relations between science and religion. Both works were translated into multiple languages. Draper’s History went through more than 50 printings in the US alone, was translated into 20 languages and, notably, became a bestseller in the late Ottoman empire, where it informed Atatürk’s understanding that progress meant science superseding religion.

Today, people are less confident that history moves through a series of set stages toward a single destination. Nor, despite its popular persistence, do most historians of science support the idea of an enduring conflict between science and religion. Renowned collisions, such as the Galileo affair, turned on politics and personalities, not just science and religion. Darwin had significant religious supporters and scientific detractors, as well as vice versa. Many other alleged instances of science-religion conflict have now been exposed as pure inventions. In fact, contrary to conflict, the historical norm has more often been one of mutual support between science and religion. In its formative years in the 17th century, modern science relied on religious legitimation. During the 18th and 19th centuries, natural theology helped to popularise science.

The conflict model of science and religion offered a mistaken view of the past and, when combined with expectations of secularisation, led to a flawed vision of the future. Secularisation theory failed at both description and prediction. The real question is why we continue to encounter proponents of science-religion conflict. Many are prominent scientists. It would be superfluous to rehearse Richard Dawkins’s musings on this topic, but he is by no means a solitary voice. Stephen Hawking thinks that ‘science will win because it works’; Sam Harris has declared that ‘science must destroy religion’; Stephen Weinberg thinks that science has weakened religious certitude; Colin Blakemore predicts that science will eventually make religion unnecessary. Historical evidence simply does not support such contentions. Indeed, it suggests that they are misguided.

So why do they persist? The answers are political. Leaving aside any lingering fondness for quaint 19th-century understandings of history, we must look to the fear of Islamic fundamentalism, exasperation with creationism, an aversion to alliances between the religious Right and climate-change denial, and worries about the erosion of scientific authority. While we might be sympathetic to these concerns, there is no disguising the fact that they arise out of an unhelpful intrusion of normative commitments into the discussion. Wishful thinking – hoping that science will vanquish religion – is no substitute for a sober assessment of present realities. Continuing with this advocacy is likely to have an effect opposite to that intended.

Religion is not going away any time soon, and science will not destroy it. If anything, it is science that is subject to increasing threats to its authority and social legitimacy. Given this, science needs all the friends it can get. Its advocates would be well advised to stop fabricating an enemy out of religion, or insisting that the only path to a secure future lies in a marriage of science and secularism.

By Peter Harrison, published in Aeon, September 7th 2017.

Peter Harrison is an Australian Laureate Fellow and director of the Institute for Advanced Studies in the Humanities at the University of Queensland. He is the author of The Territories of Science and Religion (2015), and the editor of Narratives of Secularization (2017).

Photo Credit

Ahmed Mater’s Magnetism.

Died  near Samarqand, (Uzbekistan), 27 October 1449

Ulugh Beg (Turkish for “great prince”) was governor of Transoxiana and Turkestan and, during the last 2 years of his life, Timurid Sultan. However, he is mostly remembered as a patron of mathematics and astronomy. In Samarqand, he founded a school and the famous astronomical observatory, where the most extensive observations of planets and fixed stars at any Islamic observatory were made. Ulugh Beg is associated with a Persian astronomical handbook (zīj) that stands out for the accuracy with which its tables were computed.

Ulugh Beg was the first‐born son of Shāhrukh (youngest son of the infamous conqueror Tīmūr or Tamerlane) and his first wife Gawharshād. He was raised at the court of his grandfather and, at the age of 10, was married to his cousin Agha Bīkī, whose mother was a direct descendent of Chingiz Khan. Thus Ulugh Beg could use the epithet Gūrgān, “royal son‐in‐law,” which had originally been used for Chingiz’s son‐in‐law.

In the years after Tīmūr’s death in 1405, Ulugh Beg became governor of Turkestan and Transoxiana, the most important cities of which were the cultural centers Samarqand and Bukhara. Although not completely divorced from affairs of state, he is better known for his interest in religion, architecture, arts, and sciences, which were fostered by the Mongols as well as by the Timurids. Ulugh Beg is said to have spoken Arabic, Persian, Turkish, Mongolian, and some Chinese. He had a thorough knowledge of Arabic syntax and also wrote poetry. Although he honored Turkic–Mongolian customs, he also knew the Quran by heart, including commentaries and citations. Ulugh Beg was also a passionate hunter.

By 1411, Ulugh Beg had developed a lively interest in mathematics and astronomy, which may have been aroused by a visit in his childhood to the remnants of the Marāgha Observatory that had been directed by Ṭūsī. In 1417, he founded in Samarqand a madrasa (religious school or college) that can still be seen on the Registan Square. At this institution, unlike other madrasas, mathematics and astronomy were among the most important subjects taught. The most prominent teacher was Qāḍīzāde al‐Rūmī, who was joined somewhat later by Kāshī.

Two extant letters by Kāshī to his father in Kāshān make clear that Ulugh Beg was personally involved in the appointment of scholars and that he was frequently present, and actively participated, in seminars, where he displayed a good knowledge of mathematical and astronomical topics. Kāshī relates how Ulugh Beg performed complicated astronomical calculations while riding on horseback. Anecdotes from other sources show that Ulugh Beg, like many other Muslim rulers, believed in astrology and fortune‐telling. He appears as a person who very much respected the scholars he appointed, and whose main objective was to reach scientific truth.

In 1420, Ulugh Beg founded his famous astronomical observatory on a rocky hill outside the city of Samarqand. Its circular main building, beautifully decorated with glazed tiles and marble plates, had a diameter of about 46 m and three stories reaching a height of approximately 30 m above ground level. The north–south axis of the main building was occupied by a huge sextant with a radius of 40 m (called Fakhrī sextant after that of Khujandī). On the scale of this instrument, which partially lay in an underground slit with a width of half a meter, 70 cm corresponded to 1° of arc, so that the solar position could be read off with a precision of 5″. On the flat roof of the main building various smaller instruments could be placed, such as an armillary sphere, a parallactic ruler, and a triquetrum. Among other instruments known to have been used in Samarqand are astrolabes, quadrants, and sine and versed sine instruments.

Although Ulugh Beg was the director of the Samarqand Observatory, Kāshī was in charge of observations until his death in 1429, after which he was succeeded by Qāḍīzāde, who died after 1440. The observational program was completed by Qūshjī, who had studied in Kirmān (southeastern Iran) before returning to Samarqand. The results of the observations made under Ulugh Beg include the measurement of the obliquity of the ecliptic as 23° 30’17” (the actual value at the time was 23° 30’48”) and that of the latitude of Samarqand as 39° 37’33” N. (modern value: 39° 40′). Furthermore, most of the planetary eccentricities and epicyclic radii were newly determined, and the longitudes and latitudes of the more than 1,000 stars in Ptolemy’s star catalogue were verified and corrected. Precession was found to amount to 51.4″ per year (corresponding to 1° in little more than 70 years; the actual value is 50.2″ per year).

The observatory of Ulugh Beg stayed in operation for little more than 30 years. It was finally destroyed in the 16th century and completely covered by earth in the course of time. In 1908, archaeologist V. L. Vyatkin recovered the underground part of the Fakhrī sextant, consisting of two parallel walls faced with marble and the section of the scale between 80° and 57° of solar altitude. Ulugh Beg’s observatory exerted a large influence on the huge masonry instruments built by Jai Singh in five Indian cities (most importantly Jaipur and Delhi) in the 18th century, more than 100 years after the invention of the telescope.

The main work with which Ulugh Beg is associated is an astronomical handbook with tables in Persian, variously called Zīj‐i Ulugh Beg, Zīj‐i Jadīd‐i Sulṭānī, or Zīj‐i Gūrgānī. In the introduction, Ulugh Beg acknowledges the collaboration of Qāḍīzāde, Kāshī, and Qūshjī, who were undoubtedly responsible for the underlying observations as well as the computation of the tables. The Zīj is in many respects a standard Ptolemaic work without any adjustments to the planetary models. It consists of four chapters dealing with chronology, trigonometry and spherical astronomy, planetary positions, and astrology, respectively. The instructions for the use of the tables, which were edited and translated into French by L. Sédillot in the middle of the 19th century, are clear but very brief and do not even include examples of the various calculations.

Thus, the most significant part of Ulugh Beg’s Zīj lies in the observations and computations underlying the tables. Most impressively, the sine table, covering 18 pages in the manuscript copies, displays the sine to five sexagesimal places (corresponding to nine decimals) for every arc minute from 0° to 87° and to six sexagesimal places (11 decimals) between 87° and 90°. All independently calculated values for multiples of 5′ are correct to the precision given, whereas the intermediate values, calculated by means of quadratic interpolation, contain incidental errors of at most two units. Also most of the planetary tables in the Zīj were calculated to a higher precision than before. New types of tables were added that simplified the calculation of planetary positions. Ulugh Beg’s star catalog for the year 1437 represents the only large‐scale observations of star coordinates made in the Islamic realm in the medieval period. (Most other catalogs simply adjusted Ptolemy’s ecliptic coordinates for precession or were limited to a relatively small number of stars.)

Ulugh Beg’s Zīj was highly influential and continued to be used in the Islamic world until the 19th century. It was soon translated into Arabic by Yaḥyā ibn ʿAlī al‐Rifāʿī and into Turkish by ʿAbd al‐Raḥmān ʿUthmān. Reworkings for various localities were made in Persian, Arabic, and Hebrew by scholars such as ʿImād al‐Dīn ibn Jamāl al‐Bukhārī (Bukhara), Ibn Abī al‐Fatḥ al‐Ṣūfī (Cairo), Mullā Chānd ibn Bahāʾ al‐Dīn and Farīd al‐Dīn al‐Dihlawī (both Delhi), and Sanjaq Dār and Husayn Qusʿa (Tunis). Commentaries to the Zīj were written by Qūshjī, Mīram Chelebī, Bīrjandī, and many others. Hundreds of manuscript copies of the Persian original of Ulugh Beg’s Zīj are extant in libraries all over the world. Already in 17th‐century England, various parts of the Zīj were published in edition and/or translation.

Little is known about other works of Ulugh Beg. A marginal note by him in the India Office manuscript of Kāshī’s Khāqānī Zīj presents a clever improvement of a spherical astronomical calculation. A Risāla fī istikhrāj jayb daraja wāḥida (Treatise on the extraction of the sine of 1°) has been attributed to Ulugh Beg on the basis of a citation in Bīrjandī, although most manuscripts of this work mention Qāḍīzāde as the author. Aligarh Muslim University Library lists a treatise Risāla‐yi Ulugh Beg that is yet to be inspected. Finally, an astrolabe now preserved in Copenhagen and made in 1426/1427 by Muḥammad ibn Jaʿfar al‐Kirmānī, who is known to have worked at the observatory in Samarqand, was originally dedicated to Ulugh Beg.

In 1447, Ulugh Beg succeeded his father Shāhrukh as sultan of the Timurid empire. However, he was killed on the order of his son ʿAbd al‐Laṭīf. An investigation of Tīmūr’s mausoleum by Soviet scholars in the 1940s showed that Ulugh Beg was buried as a martyr in accordance with Sharīʿa (Islamic law), i. e., fully clothed in a sarcophagus.

By Benno van Dalen, Ulugh Beg: Muḥammad Ṭaraghāy ibn Shāhrukh ibn Tīmūr, The Biographical Encyclopedia of Astronomers, pp 1157-1159.

Selected References

Bagheri, Mohammad (1997). “A Newly Found Letter of Al‐Kāshī on Scientific Life in Samarkand.” Historia Mathematica 24: 241–256.

Barthold, V. V. (1958). Four Studies on the History of Central Asia. Vol. 2, Ulugh‐Beg. Leiden: E. J. Brill.

Kary‐Niiazov, T. N. (1950). Astronomicheskaya shkola Ulugbeka (The astronomical school of Ulugh Beg) (in Russian). Moscow: Akademia Nauk SSSR. (Second enlarged edition in Kary‐Niiazov, Izbrannye trudy [Collected works]. Vol. 6. Tashkent: FAN, 1967.)

——— (1976). “Ulugh Beg.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 13, pp. 535–537. New York: Charles Scribner’s Sons.

Kennedy, E. S. (1956). “A Survey of Islamic Astronomical Tables.” Transactions of the American Philosophical Society, n.s., 46, pt. 2: 121–177, esp. 125–126 and 166–167. (Reprint, Philadelphia: American Philosophical Society, 1989.)

——— (1960). “A Letter of Jamshīd al‐Kāshī to His Father: Scientific Research and Personalities at a Fifteenth Century Court.” Orientalia 29: 191–213. (Reprinted in E. S. Kennedy, et al., Studies in the Islamic Exact Sciences, edited by David A. King and Mary Helen Kennedy. Beirut: American University of Beirut, 1983, pp. 722–744.)

——— (1998). “Ulugh Beg as Scientist.” Chapter 10 in Astronomy and Astrology in the Medieval Islamic World. Aldershot: Ashgate. (Describes the marginal note by Ulugh Beg in a manuscript of Kāshī’s Zīj.)

Knobel, Edward Ball (1917). Ulugh Beg’s Catalogue of Stars: Revised from All Persian Manuscripts Existing in Great Britain, with a Vocabulary of Persian and Arabic Words. Washington: Carnegie Institution of Washington.

Krisciunas, Kevin (1992). “The Legacy of Ulugh Beg.” In Central Asian Monuments, edited by H. P. Paksoy, pp. 95–103. Istanbul: Isis. (Includes a bibliography of all publications of parts of the Zīj of Ulugh Beg.)

——— (1993). “A More Complete Analysis of the Errors in Ulugh Beg’s Star Catalogue.” Journal for the History of Astronomy 24: 269–280.

Kunitzsch, Paul (1998). “The Astronomer al‐Ṣūfī as a Source for Uluġ Beg’s Star Catalogue.” In La science dans le monde iranien ā l’époque islamique, edited by Ž. Vesel, H. Beikbaghban, and B. Thierry de Crussol des Epesse, pp. 41–47. Tehran: Institut français de recherche en Iran.

Manz, Beatrice F. (2000). “Ulugh Beg.” In Encyclopaedia of Islam. 2nd ed. Vol. 10, pp. 812–814. Leiden: E. J. Brill.

Rosenfeld, B. A. and Jan P. Hogendijk (2002/2003). “A Mathematical Treatise Written in the Samarqand Observatory of Ulugh Beg.” Zeitschrift für Geschichte der Arabisch‐Islamischen Wissenschaften 15: 25–65.

Sayılı, Aydın (1960). The Observatory in Islam. Ankara: Turkish Historical Society, esp. pp. 260–289.

———(1960). Ghiyâth al‐Dîn al Kâshî’s Letter on Ulugh Beg and the Scientific Activity in Samarqand. Ankara: Turkish Historical Society.

Schoy, Carl (1927). Die trigonometrischen Lehren des persischen Astronomen Abū ʾl‐Rayḥān Muḥammed ibn Aḥmed al‐Bīrūnī dargestellt nach al‐Qānūn al‐Masʿūdī. Hanover: Lafaire. (Reprinted in Schoy, Beiträge zur arabisch‐islamischen Mathematik und Astronomie, edited by Fuat Sezgin, Vol. 2, pp. 629–746. Frankfurt am Main: Institute for the History of Arabic‐Islamic Science, 1988.) (Includes an edition of parts of Ulugh Beg’s sine and tangent tables.)

Sédillot, Louis P. E. Amélie (1847). Prolégomènes des tables astronomiques d’Oloug‐Beg. Publiés avec notes et variantes et précédés d’une introduction. Paris: Firmin Didot.

——— (1853). Prolégomènes des tables astronomiques d’Oloug‐Beg. Traduction et commentaire. Paris: Firmin Didot.

Shevchenko, Mikhail Yu (1990). “An Analysis of Errors in the Star Catalogues of Ptolemy and Ulugh Beg.” Journal for the History of Astronomy 21: 187–201.

Photo Credit

PHOTO YOKO AZIZ/ALAMY
The Ulugh Beg Observatory in Samarqand, Uzbekistan, completed in the fifteenth century, was used by several famous Islamic astronomers.

In the last few decades, a critical mass of excellent studies by competent historians of Islamic science has led to a qualitative shift in our understanding of this history. Yet despite this shift, an integrated approach to the study of the history of science in Muslim societies still needs to overcome some real hurdles. To start with, such an undertaking calls for an examination of wide-ranging cultural activities, in a vast geographical area, under different historical conditions, and for a period of at least seven centuries. Moreover, the sources for the study of this subject are daunting, and they include, in addition to material evidence, thousands of scientific manuscripts, most of which remain unexamined. The abundance of evidence also gives rise to a number of methodological difficulties: earlier surveys of the history of Islamic science were based on a handful of random studies of scientific treatises. Some of the actual studies were of a high quality; yet ironically, the paucity of hard evidence available to early scholars often enabled them to cover all the fields of science in all-inclusive, and often reductive, narratives. In the last few decades, many more scientific treatises have been critically examined, with the dual effect of providing detailed information about the various scientific disciplines, and highlighting the peculiarity of the history of each separate discipline or even fields within disciplines.

In the absence of thorough and exhaustive accounts for developments in the various scientific disciplines as well as accounts for the epistemological foundations of these sciences, it only stands to reason that attempts to provide general characterizations of science in Muslim societies and its relation to religion can only be provisional and subject to scrutiny. Even such seemingly straight forward characterizations of the scientific activity in Muslim societies as Islamic or Arabic cannot be taken for granted, and the same applies to the assertion that Islam has either a positive or a negative attitude towards science. I do not mean here to deny the validity of using terms such as “Islamic science”, but simply to stress the importance of addressing the question of methodology before venturing such general characterizations.

Due to the extent of the scientific enterprise in classical Muslim societies, the question of the relationship between science and religion in Islam can be approached from many different perspectives, and may vary according to, and within, the region, period, or discipline under consideration. For example, one may look at standard discussions among religious scholars and theologians. Alternatively, the classifications of the sciences provide an epistemological perspective which pertains to theories of knowledge. One can also examine and attempt to classify the manifold views of scientists as well as religious scholars on the relationship between science and religion. In this essay, I will restrict myself to the field of astronomy; in particular, I will compare two important trends of research in theoretical astronomy. Astronomy, I should add, is especially relevant to the question of the relationship between science and religion because of its cosmological dimension and the relative ease with which it can be invoked in connection with metaphysical questions. The main focus in this paper is on the way communities of scientific knowledge conceived of their profession and research within the larger context of religion. However, I will first say a few words about religious scholars who discussed science and proposed “Islamic” assessments of the various sciences.

Almost invariably, discussions of the Islamic attitude toward science invoke the works of al-Ghazali (d. 505/111). I will not attempt to summarize Ghazali¹s views on the various sciences; these views have received more scholarly attention than those of any other Muslim scholar who had written on the subject. It is important to note, however, that the debate regarding Ghazali¹s true attitudes and views continues among contemporary scholars, and there seems to be no consensus even over the interpretation of his most obvious work, Tahafut al-Falasifa (The Incoherence of the Philosophers), let alone an integrated assessment of his whole oeuvre, including such relevant works to our subject as al-Iqtisad fi al-IŒtqad, MiŒyar al-ŒIlm, al-Qustas al-Mustaqim, Maqasid al-Falasifa, and al-Mustasfa min ŒIlm al-Usul.

Aside from al-Ghazali and whether he actually condoned, neglected, or opposed the sciences, there are, to be sure, some radical and credible traditionalists, such as Ibn Taymiyya (d. 1328), who attacked some of the fields of knowledge that Ghazali condoned, but in the face of these there are equally radical and popular traditionalists, such as Ibn Hazm (11th century), who defended logic and argued for the interconnection between the various sciences. What is more important about the provocative writings of Ibn Taymiyya with such titles as “The Rebuttal of Logic” and “The attack on Logicians” is that Ibn Taymiyya employed the discourse of formal logic, and rather than deny the validity of logic, he only denies the claim by a professional group of logicians to have an exclusive monopoly over methods of arriving at Truth. Moreover, Ibn Taymiyya questioned the validity of some of the propositions and syllogisms of certain kinds of formal logic, and not all kinds of logic. Furthermore, Ibn Taymiyya criticized Ghazali¹s denial of causality and was a strong believer in physics and the natural laws. Again, the purpose of citing these authors here is not to provide an exhaustive analysis of their views, but simply to point out the diversity as well as complexity of the views of traditional Muslim scholars on science and scientific knowledge.

The differences between these traditional religious scholars highlight the difficulty of identifying a unified, traditional Islamic attitude toward science. It is clear, however, that the overall outcome of the religious debates over scientific knowledge was to naturalize some of the exact sciences and to provide Islamic justifications for certain kinds of scientific knowledge. Such was the assessment of the famous 14th century historian Ibn Khaldun who remarks in his Muqaddima that after Ghazali all religious scholars studied logic, but they studied it from new sources, such as the works of Ibn al-Khatib and al-Khunji (13th century), and that people stopped using the books of the ancients; “the books and the methods of the ancients”, says Ibn Khaldun, “are avoided, as if they had never been”. Later, he adds (p. 143) “It should be known that the early Muslims and the early speculative theologians greatly disapproved of the study of this discipline [logic]. They vehemently attacked it and warned against it… Later on, ever since al-Ghazzali and the imam Ibn al-Khatib, scholars have been somewhat more lenient in this respect. Since that time, they have gone on studying (logic)…”

Generally speaking, therefore, religious assessments of the epistemic value of various kinds of scientific knowledge were nuanced and diverse. And although one cannot adduce a direct and mechanical correlation between the religious arguments and the ways in which scientists perceived of and theorized their own scientific disciplines, it is abundantly clear that the views of scientists were also manifold. Furthermore, since they were inspired by a variety of cultural factors, these articulations by scientists are obvious and tangible expressions of what “Islamic” science meant in actual history, and are as indicative of the Islamic dimension as the views expressed by religious scholars. In what follows, I will approach the question of the relationshipbetween science and religion by focusing on two particular traditions of astronomical research, one in the Muslim east and the other in the Muslim west. My interest is in charting out the peculiar modes of thinking that provided the epistemological and methodological conditions for the formation of these two traditions, and the diverse conceptual frameworks that informed the different planetary theories proposed in each.

Ever since Sarton¹s attempt to write a universal history of science, the Islamic sciences have had a considerable presence in various accounts of this history. Despite their large quantitative presence, however, Islamic sciences are all too often absent from grand, integrative narratives of the history of science. When historians offer conceptual analysis of epochal changes in the history of science (which is something they often do), the cumulative legacy of the Islamic sciences is simply overlooked. Conceptually, the Islamic scientific legacy is seen as a rather mechanical continuation of the Greek one: the Islamic sciences expanded and refined the Greek sciences without departing from them conceptually. A justification of this oversight is seldom provided, but when it is, it usually has to do with the role of philosophy or theory in science. In the field of astronomy in particular, theoretical considerations were often overlooked on the basis of a widely held assumption that Islamic science was practical and hence theoretically or philosophically shallow. The decline of Islamic science, according to this view, was a result of the lack of theoretical rigor. In the last few decades, however, an alternative view has been proposed, often by competent historians of science. In contrast to the notion that the Islamic sciences declined because of their feeble philosophical foundations, historians of astronomy now argued that the motivation for the most important tradition of astronomical reform in the Muslim world was philosophical. Despite its different understanding of the role of philosophy in connection with the science of astronomy, this thesis often served to undermine the “scientific” value of these astronomical reforms.

In a sense, the two different views regarding the role of philosophy in Islamic science echo a fundamental debate over the function of scientific theory. Simply put, scientist and philosophers (as well as historians of science) differ over whether the primary role of scientific theory is to explain nature as it exists in reality or simply describe and predict its appearance as we perceive it. In the latter case (description and prediction), the quest of science is to “save the phenomena,” whereas in the former case, science goes beyond appearance to explore causal connections or, in the language of philosophers, “first causes.” This philosophical controversy, and many variations of it, is at the roots of the emergence of what is commonly called “modern science”, and it continues to inform modern and postmodern debates on the relationship between scientific knowledge and others forms of knowledge. This controversy has also influenced readings of the history of “non-western” science. Before examining the question of the role of theory in science as reflected in the two Islamic traditions of astronomical reform, a few words on the early developments in Islamic astronomy that provided the background for the latter reform traditions.

Astronomy was one of the oldest, most developed and most esteemed exact sciences of antiquity. (Many of the mathematical sciences were originally developed to facilitate astronomical research. Various disciplines and belief systems intersected and interacted in astronomy, including physics and metaphysics, as well as mathematics and religion. Islamic/Arabic astronomy was also culturally hybrid (Babylonian, Indian, Persian, and Greek), and intimately connected to politics (astrology, dynastic legitimization). Finally, practical considerations such as finding one’s direction during night travel, and the correlation between the seasons of the year and the positions of the planets provided additional incentives for the study of astronomy. For all of these reasons, astronomical research was hybrid and spirited, and the field of astronomy provided fertile grounds for questioning old conceptions and developing and testing new ones.

The first astronomical texts that were translated into Arabic in the eighth century were of Indian and Persian origin. The real emergence of Arabic astronomy, however, occurred in the ninth century at which time the major Greek astronomical texts were translated. Right from its very beginnings in the ninth and all the way till the sixteenth century, astronomical activity was wide-spread and intensive. This activity is reflected in the large number of scientists working in practical and theoretical astronomy, the number of books written, the active observatories, and the new observations.

Arabic astronomy was first exposed to Persian and Indian astronomy, and it continued to use some of the parameters and methods of these two traditions, yet the greatest formative influence on Arabic astronomy is undoubtedly Greek. Early in the ninth century, astronomers realized that the Greek astronomical tradition was far superior to the other two, both in its comprehensiveness and its use of effective geometrical representations. One particular Greek author, and more specifically one work by this author, exerted a disproportionate influence on all of medieval astronomy through the whole of the Arabic period and until the eventual demise of the geocentric astronomical system. This is the Almagest of Ptolemy (second century AD). That this text should exert so much influence is neither accidental nor surprising, for it is the highest achievement in Hellenistic mathematical astronomy, and one of the greatest achievements of all of Hellenistic science.

The Almagest was rightly considered the main authoritative work of antiquity on Astronomy. In this book, Ptolemy synthesizes the earlier knowledge of Hellenistic astronomy in light of his own new observations. The main purpose of the book is to establish the geometric models which would accurately account for observational phenomena. A large part of the book is dedicated to the methods for constructing various models and for calculating the parameters of these models. Ptolemy also provides tables for planetary motions to be used in conjunction with his models. Of all the books of antiquity, the Almagest represents the most successful work of mathematical astronomy: its geometric representations of the universe provided the most accurate and best predictive accounts for the celestial phenomena. A Greek tradition of physical astronomy is also reflected in the Almagest and in Ptolemy’s other influential work, the Planetary Hypothesis. According to this predominantly Aristotelian tradition, the universe is organized into a set of concentric spheres, each carrying a star and rotating around the stationary earth at the center of the universe. In contrast to sublunary rectilinear motion, the heavenly bodies move in perfect uniform circular motions. Ptolemy adopted, at least in theory, the two basic Aristotelian principles: that the earth is stationary at the center of the universe, and that the motion of heavenly bodies ought to be represented by a set of uniform circular motions. In practice, mathematical considerations often forced Ptolemy to disregard the second of these principles. However, against his better “mathematical” judgement, the only physical theory or cosmology available to Ptolemy was that of Aristotle. Ptolemy thus had no other option but to profess his adherence to this cosmology, an adherence which gave rise, in the Islamic period and later in Europe, to a long and fruitful tradition of astronomical reform.

Astronomical reform in the Islamic period took different forms. Under the Caliph al-Ma¹mun, a program of astronomical observations was organized in Baghdad and Damascus. Like any organized research project, this program endowed astronomical activity in the Islamic world with formal prestige. The professed purpose of this program was to verify the Ptolemaic observations by comparing the results derived by calculation, based on the Ptolemaic models, with actual observations conducted in Baghdad and Damascus some 700 years after Ptolemy. The results were compiled in al-Zij al-Mumtahan (The verified tables), which is no longer extant in its entirety, but is widely quoted by later astronomers. The most important correction introduced was to show that the apogee of the solar orb moves with the precession of the fixed stars. On a more general note, this program stressed the need for continuing verification of astronomical observations, and for the use of more precise instruments.

Thus, right from its beginnings, Arabic astronomy set out to rectify and complement Ptolemaic astronomy. Having noted several discrepancies between new observations and Ptolemaic calculations, astronomers then proceeded to reexamine the theoretical basis of Ptolemy’s results. This critical reexamination took several forms. Although the general astronomical research of this period (ninth century) is conducted within the framework of Ptolemaic astronomy, this research reworked and critically examined the observations and the computational methods of this astronomy and, in a limited way, was able to explore problems outside its set frame. The application of diverse mathematical disciplines to each other also had the immediate effect of expanding the frontiers of disciplines and introducing new scientific concepts and ideas. The use of systematic mathematization transformed the methods of reasoning and enabled, in turn, further creative developments in the branches of science.

In the tenth and eleventh centuries, the earlier examinations of Ptolemaic astronomy led to systematic projects which, rather than addressing the field in its totality, focused on specific aspects of astronomy. One of the main characteristics of this period was the tendency to provide exhaustive synthesizing works on particular astronomical topics, culminating in Biruni¹s (973-c. 1048) al-Qanun al-MasŒudi, a synthesis of the Greek, Indian, and Arabic astronomical traditions. It is with Biruni that we have the first systematic discussion, by a scientist (astronomer), of the relationship between science and philosophy. A book entitled al-As¹ila wal-Ajwiba (questions and answers) preserves an exchange between Biruni and his contemporary Ibn Sina, the most celebrated Muslim philosopher of all time. Biruni presents Ibn Sina with a set of questions in which he criticizes Aristotle’s physical theory, especially as it pertains to astronomy. Ibn Sina then responds, and a lively debate ensues. In the course of this exchange, Biruni questions almost all of the fundamental Aristotelian physical axioms: he rejects the notion that heavenly bodies have an inherent nature, and asserts that their motion could very well be compulsory; he maintains that there is no observable evidence that rules out the possibility of vacuum; he further asserts that, although observation corroborates Aristotle’s claim that the motion of heavenly bodies is circular, there is no inherent “natural” reason why this motion cannot be, among other things, elliptical. What is more significant than the actual objections raised by Biruni is the argument he employs in the course of the debate. Biruni draws a distinction between his vocation and that of Aristotle and Ibn Sina. He seems to argues that the metaphysical axioms on which philosophers build their physical theories do not constitute valid evidence for the mathematical astronomer. In other words, Biruni clearly distinguishes between the philosopher and the mathematician, the metaphysician and the scientist. He conceives of himself as a mathematical astronomer for whom the only valid evidence is observational or mathematical. Biruni’s example illustrates how the systematic application of rigorous mathematical reasoning led to the mathematization of astronomy and, by extension, to the mathematization of nature. Rather than subsuming the various sciences under the all-encompassing umbrella of philosophy, many scientists considered their professions as autonomous mathematical enterprises, separate from, and on par with philosophy.

As I noted earlier, Ptolemy had taken the liberty to propose models that did not conform to Aristotelian cosmology; so how does Biruni¹s example differ from that of Ptolemy? Put differently, can we think of both Ptolemy and Biruni as prototypes for scientists that are interested in the descriptive functions of science, in “saving the phenomena,” as opposed to scientists seeking to explain and not just describe? I will try to answer this question by comparing two traditions of astronomical reform in the Muslim east and west.

Traditions of astronomical reform in the Islamic period

Building on the cumulative achievements of Arabic astronomy, the eleventh century witnessed the emergence of a new tradition of astronomical research. After the eleventh century, the efforts of most theoretical astronomers were directed towards providing a thorough evaluation of the physical and philosophical underpinnings of Ptolemaic astronomy, and proposing alternatives to it. It should be noted here that the emergence of this tendency in astronomical research does not represent a move away from the thorough mathematical examination of astronomy, but is an outcome of this increasing mathematization. This line of research was pursued by several eleventh-century scientists. In a book entitled Tarkib al-Aflak, Abu ŒUbayd al-Juzjani (d. c. 1070) indicates that both he and his teacher, Ibn Sina, were aware of the o-called equant problem of the Ptolemaic model. Juzjani even proposes a solution for this problem. The author of an anonymous Andalusian astronomical manuscript refers to another work which he composed under the title al-Istidrak Œala Batlamyus (recapitulation regarding Ptolemy), and indicates that he included in this book a list of objections to Ptolemaic astronomy. The most important work of this genre, however, was written in the same period by Ibn al-Haytham (d. 1039). In his celebrated work Al-Shukuk Œala Batlamyus (doubts on Ptolemy), Ibn al-Haytham sums up the physical and philosophical problems inherent in the Greek astronomical system, and provides an inventory of the theoretical inconsistencies of the Ptolemaic models. The tradition of astronomical reform thrived in the thirteenth century, climaxed in the fourteenth, and continued well into the fifteenth and sixteenth centuries. Most astronomers of this period took up the theoretical challenge outlined by Ibn al-Haytham, attempted to rework the models of Ptolemaic astronomy and to provide, with varying degrees of success, alternatives to these models. The list of astronomers working within this tradition comprises some of the greatest and most original Muslim scientists. The astronomers who have received modern scholarly attention include: Mu¹ayyad al-Din al-ŒUrdi (d. 1266), Nasir al-Din al-Tusi (d. 1274), Qutb al-Din al-Shirazi (d. 1311), Sadr al-ShariŒa al-Bukhari (d. 1347), Ibn al-Shatir (d. 1375), and ŒAla¹ al-Din al-Qushji (d. 1474).

To appreciate the technical aspects of these astronomical reforms, a quick overview of some aspects of Ptolemaic astronomy is in order. In his Almagest, Ptolemy used the results of earlier Hellenistic astronomy and incorporated them into one great synthesis. Of particular geometrical utility was the concept of eccentrics and epicycles developed by Hipparchus (second century BC) and adopted by Ptolemy. In an astronomical representation employing the eccentric model (Figure 1), a planet is carried on the circumference of an eccentric circle which rotates uniformly around its own center G. This center, however, does not coincide with the location O of an observer on the earth. As a result, the speed of the planet appears to vary with respect to the observer at O. In an epicyclic model, the planet P is carried on the circumference of an epicycle, whose center is in turn carried on a circle called the deferent, which rotates uniformly around the center of the universe, the earth. Viewed by an observer at point O, the combination of the two uniform motions of the deferent and the epicycle produces a non-uniform motion which is mathematically equivalent to the motion of the eccentric model.

(Not Shown)
Figure 1

The Ptolemaic model for the motion of the sun utilized either a simple eccentric or the equivalent combination of a deferent and an epicycle. All the other Ptolemaic models for planetary motions were considerably more complex. For example, in the model for the longitudinal motion of the upper planets Mars, Jupiter and Saturn (Figure 2), the center G of the deferent circle no longer coincides with the earth O; moreover, the uniform motion of the center of the epicycle on the circumference of the deferent is measured around the point E, called the equant center, rather than the center G of the deferent. Ptolemy proposed this model because it allowed for fairly accurate predictions of planetary positions. However, circle G in this model is made to rotate uniformly around the equant E which is not its center. This represented a violation of the Aristotelian principle, adopted by Ptolemy, of uniform circular motion around the Earth, the stationary center of the universe. In other words, for the sake of observation, Ptolemy was forced to breach the physical and philosophical principles on which he built his astronomical theory. Other Ptolemaic models were even more complex, and with each additional level of complexity new objections were raised against Ptolemaic astronomy.

(Not Shown)
Figure 2

Other objections raised by Ibn al-Haytham and taken up by later astronomers include the problem of the prosneusis point in the model for the longitudinal motion of the moon; the problem of the inclination and deviation of the spheres of Mercury and Venus; the problem of planetary distances, and so on. In the case of the moon, additional difficulties arise because Ptolemy’s model has a deferent center which is itself moving; moreover, the motion of the center of the epicycle on this deferent is not uniform around the deferent’s center; rather, it rotates uniformly around the center of the world. To complicate matters further, the anomalistic motion on the epicycle is measured away from the mean epicyclic apogee, that is aligned with a movable point called the prosneusis point, rather than being measured from the true apogee, that is aligned with the center of the world. This prosneusis point is the point diametrically opposite to the center of the deferent on the other side of the center of the world. The model for the longitudinal motion of Mercury contained complex mechanisms that were equally objectionable. Additional complications also resulted from the motion of the planets in latitude: the motion in longitude is measured on the plane of the ecliptic which is the great circle of the celestial sphere that traces the apparent yearly path of the sun as seen from the earth. The deferents of the Ptolemaic models, however, did not coincide with this plane. The least problematic is the case of the lunar model, where the deferent has a fixed inclination with respect to the ecliptic, and the epicycle lies in the plane of the deferent. However, the epicycles of the upper planets do not lie in the plane of the deferent, and they have a variable deviation with respect to it. In the case of the lower planets, both the inclination of the deferent with respect to the ecliptic and that of the epicycle with respect to the deferent are variable. Without getting into details, one can easily imagine the complexity and potential problems of the Ptolemaic models which attempted to account for these see-saw and oscillation motions.

The astronomers who attempted to solve the above problems can be classified into two general schools: a mathematically oriented school which was predominantly in the eastern parts of the Muslim world, and a philosophically oriented school based in the western regions of the empire. The name “Maragha school” is often given to the eastern reformers in recognition of the achievements of a number of astronomers working in an observatory established at Maragha. Whereas the contributions of these astronomers are no doubt monumental, it should be noted that the reform of Ptolemaic astronomy started before the establishment of the Maragha observatory in the thirteenth century, and reached its highest point in the fourteenth. In fact, some of the astronomers of the Maragha group seem to have started their reform projects even before they joined this observatory; they were perhaps invited to join the observatory team because they were already engaged in such research. The eastern reform tradition, then, was too diffused to be associated with any one geographical area or period; rather, it characterizes several centuries of Arabic astronomical research throughout the Eastern domains of the Muslim world.

Astronomers of the eastern reform tradition adopted several mathematical strategies in their attempts to solve the theoretical problems of the Ptolemaic models. One of their main objectives was to come up with models in which the motions of the planets could be generated as a result of combinations of uniform circular motions, while at the same time conforming to the accurate Ptolemaic observations. Two useful and extremely influential mathematical tools were invented by Tusi and ŒUrdi. The first tool, known in modern scholarship as the Tusi couple, in effect produces linear oscillation as a result of a combination of two uniform circular motions. The tool was used in various ways by many astronomers including Copernicus. The ŒUrdi lemma is an equally versatile mathematical tool used by ŒUrdi and his successors. To produce optimal representations that are physically and mathematically sound, other astronomers used various combinations of these two tools, and devised additional tools of their own invention. In addition, other mathematical solutions were proposed to resolve the contradictions inherent in the Ptolemaic models. For example, ŒUrdi reversed the direction and tripled the magnitude of motion of the inclined sphere in the Ptolemaic lunar model; he was thus able to produce uniform motion around the geometric center of the sphere, while at the same time reproducing the uniform motion around the old Ptolemaic center. The most comprehensive and successful models were introduced in the fourteenth century by the Damascene astronomer Ibn al-Shatir; his models for all the planets utilize combinations of perfect circular motions where each circle rotates uniformly around its center. Ibn al-Shatir was also able to solve problems of planetary distances, and to provide more accurate accounts for observations.

The development of Arabic astronomy in al-Andalus and North Africa followed different routes. The beginnings of significant scientific activity in al-Andalus started in the ninth century; yet this activity was almost completely dependent upon and lagging behind the sciences of the eastern part of the Muslim world. Between the ninth and eleventh centuries, however, a full-fledged scientific tradition emerged. Many scientists traveled east to study science; scientific books were systematically acquired and large private and public libraries were established. A solid familiarity with the eastern astronomical tradition led, in the eleventh century, to an intensive and at times original astronomical activity. The emphasis of the activity of these and other astronomers was focused on the compilation of tables and on spherical astronomy. Their primary original contributions were limited to some new observations, but mostly to the mathematics of the trepidation movement of the stars, as well as to the invention of highly sophisticated astronomical instruments. During this entire period, however, little work of significance was devoted to planetary theory.

In contrast to the earlier period, the focus of astronomical research in al-Andalus and North Africa in the twelfth century shifted to planetary theory. The names associated with this research tradition include Ibn Baja (d. 1138), Jabir Ibn Aflah (fl. 1120), Ibn Tufayl (d. 1185), Averroes (d. 1198), and Al-Bitruji (fl. 1200). Of these, Al-Bitruji was the only one to formulate an alternative to Ptolemaic astronomy, while the others produced philosophical discussions of this astronomy. Both the discourses on Ptolemaic astronomy, as well as the actual proposed model of al-Bitruji, conceived of astronomical reform in reactionary terms-that is, in terms of adopting older and mathematically inferior models in place of the ones used since Ptolemy. The aim of the western school was to reinstate Aristotelian homocentric spheres, and to completely eliminate any use of eccentrics and epicycles. In accordance with the most stringent and literal interpretations of Aristotelian principles, the western researchers demanded that the heavens be represented exclusively by nested homocentric spheres and perfect uniform circular motions. Even epicycles and deferents that rotated uniformly around their centers were not tolerated, because their use entailed an attribution of compoundednesss to heavenly phenomena; according to Aristotelian principles, the heavens are perfectly simple. However, since the predictive power of the Ptolemaic models and their ability to account for the observed phenomena relied on the use of epicycles and eccentrics, the western models were strictly qualitative and philosophical, and were completely useless from a mathematical point of view. These models were neither numerically verifiable, nor could they be used for predicting planetary positions. It is no wonder, therefore, that all but one of the western philosophers did not bother to produce actual geometrical models.

The significance of the difference between the eastern and western reform traditions of Arabic astronomy cannot be overemphasized. The prevalent view in contemporary scholarship attributes the steady decline of the intellectual sciences in al-Andalus and North Africa to the rise of the so-called “fundamentalist” states of the Almoravids (1091-1144) and Almohads (1147-1232). It was precisely during this period, however, that the greatest Andalusian philosophers worked under the patronage of the rulers of these two states. What we have, therefore, is not a steady decline of the intellectual disciplines, but the rise of some at the expense of others. The decline of mathematical astronomy has nothing to do with the Almoravids or the Almohads, nor with an alleged theological counter-revolution. Rather, the decline is a result of the adoption of a specific research program of astronomical research, a program which is driven by the untenable, and by then outdated, Aristotelian philosophical concerns that proved incompatible with the advanced mathematical and scientific aspects of astronomy.

In sharp contrast with the western school, the eastern school of Arabic astronomy did not favor philosophy at the expense of mathematics. The objections of this school were mathematical and physical and, as the comparison with their western counterpart clearly illustrates, these objections were certainly not philosophical. A common view which is prevalent in earlier studies maintains that the eastern reform tradition of Arabic astronomy was driven by philosophical considerations, a notion which is often used to undermine the mathematical and scientific significance of this tradition. Given the overwhelming evidence of detailed research on this tradition, such a view is no longer tenable. The alternative solar model proposed by Ibn al-Shatir is an example in which reform was motivated by purely observational considerations, even though the Ptolemaic model was completely unobjectionable from a physical or philosophical point of view. More generally, the eastern tradition of astronomical reform has its roots in the systematic mathematization of astronomy and, to some extent, even of nature itself. A recent study of the al-Takmila fi Sharh al-Tadhkira of al-Khafri (d. 1525) clearly illustrates one of the main characteristics of this tradition. Al-Khafri was primarily a religious scholar who wrote a highly sophisticated commentary on the Tadhkira of Nasir al-Din al-Tusi, one of the classics of the eastern reform tradition. Al-Khafri presents in this work thorough accounts for the various alternative models proposed by arlier astronomers. The purpose of this presentation, however, is not to look for a correct model, nor to decide which one conforms with an ideal or preferred cosmology, but to establish the mathematical equivalence of all of these models.

Now to go back to the question I raised earlier, namely whether we can think of this tradition of astronomical research as an expansion of the descriptive tendency started by Ptolemy himself. The answer, in my view, is no. To start with, it would be inaccurate to talk of a mathematical school and a philosophical school in Greek astronomy, since the astronomers who provided mathematical models in violation of Aristotelian physics did not theorize the superiority of mathematical principles over philosophical ones. Moreover, this supposed school of mathematical astronomy culminated in Ptolemy, who considered his models defective because they did not conform fully with Aristotelian cosmology. In contrast, in the case of the eastern Islamic astronomical tradition, the proposed mathematical models were deliberate theoretical and epistemological choices that were conceived as alternatives to the philosophical choice. This reform tradition thus shifted the understanding of physics from metaphysics to mathematics. In turn, this shift laid the foundation for the demise of Aristotelian physics and for the emergence of the new sciences. Despite the diversity of their proposed solutions, a shared, fundamental change introduced by the astronomers of the Muslim east is in the understanding of what constitutes a principle. The principles employed by these astronomers did not derive from philosophical speculation about the nature of heavenly bodies (as in the case of the principles adopted by Ptolemy), but from mathematics. Such is, for example, the principle that the uniform motion of a sphere can only be around an axis passing through its center, since any other rotation is, by definition, non-uniform. At the same time, ŒUrdi, for example, does not hesitate to reverse the direction of the motion in his proposed model, simply because he can reproduce the Ptolemaic observations while employing spheres that rotate uniformly around their own centers; ŒUrdi could not have possibly conceived of this reversed motion as one that corresponds to reality, but only as one that allows accurate predictions of planetary positions. Likewise, Tusi¹s couple and ŒUrdi¹s lemma were pure mathematical tools that had no physical counterpart. While the objective of the western Islamic astronomical tradition was to save the (meta)-physical theory, that of the eastern tradition was to save the phenomena as well as the newly constituted physics. In this physics, mathematical principles were not just tools or a vehicles for studying nature but also for conceptualizing it.

Philosophy, the overarching discipline in the Greek classifications, was gradually relegated in the Islamic hierarchy of knowledge to one subdivision among many other sciences. Having isolated philosophy, Muslims could then single it out as a potential source of conflict with religion without jeopardizing the other demonstrable sciences. The western (Islamic) tradition of astronomical research subscribed to the older Greek metaphysics, whereas the eastern tradition did not. It is thus legitimate to think of this latter tradition of astronomical reform as a specific Islamic development, and of the views espoused in the formulations of members of this tradition as indications of what is “Islamic” about Islamic science. A notable characteristic of this tradition of astronomical reform is the development of mathematical principles to replace the older physical, or rather metaphysical principles of astronomy. Thus conceived, the areas in which science and religion overlap are reduced, and scientific knowledge is separated from religious knowledge. In other words, one of the consequences of the separation of science and philosophy was the separation of religion and science. To a certain extent, therefore, the Islamization of science in the practice of medieval Muslim astronomers actually meant its secularization.

By Ahmad Dallal

Review – 1001 Inventions: Muslim heritage in our world: an exhibition at the Museum of Science and Industry, Manchester, UK, to 4 June 2006

IT still comes as a surprise to discover how many children (and their parents) think that modern science is a European event, starting with the Enlightenment. Perhaps those inclined to such Eurocentrism should be packed off to the north of England to see an ambitious exhibition. Teasingly called 1001 Inventions, it may go some way towards filling in what the curators call “1000 years of missing history” by showing the role of Islamic-era science in shaping the modern world.

It might also help see off easy talk of “civilisations in collision”. The fact is that by the 12th century the Islamic empire covered a swathe of the world from Spain to Indonesia and, as with all civilisations, expansion drove scientific excellence. The exhibition captures a time when states governed by sharia law no less produced world-class innovation by scientists and translators who were Christian, Jewish, Muslim and Zoroastrian.

As with modern science, much of their research was dictated by practical need. One catalyst for developing clocks, for example, was the need for mosques to announce accurate times for the five daily prayers. Similarly, administering a large empire required postal systems, good maps and surveying techniques, research into common diseases, intensive farming and irrigation – not to mention more effective weapons of war. It also drove serious amounts of fundamental research into astronomy, chemistry and mathematics.

There were also breakthroughs that were, just as they are today, pure serendipity. One of my favourites is the story of coffee. Discovered accidentally by a livestock farmer from Ethiopia, it was embraced by the Sufis of Yemen to help them stay awake at night, and brought to London in the 17th century by a Turkish merchant. Even the word derives from the Arabic kahwa. Arabic was very much the language of culture, administration and research. Most strikingly, as the exhibition shows, some scientific English words have Arabic roots: chemistry (kimia), algebra (al-gabr), and alkali (al-qaly).

This is all excellent. But what 1001 Inventions doesn’t do is explain what happened next, and why there is so little highquality science and learning in Muslim countries today. Indices of patents and research publications make it clear that countries with mostly Muslim populations rate poorly for generating new knowledge. They have produced just two science Nobelists: Egypt’s Ahmed Zewail for chemistry and Pakistan’s Abdus Salam in physics, and even they won their honours at western universities.

Today, Islam has a record number of followers: one-fifth of humanity is Muslim. Moreover the Koran is rare among religious texts in explicitly telling readers to go learn, study and think about the nature of the world around them. If Islam inspired great learning in the past, why not now?

Perhaps one answer is crudely financial. Science needs money, but today’s Muslim states spend on average 0.2 per cent of GDP on research and development, compared with a developed-world average of more than 2 per cent.

A second answer lies in the fact that Islam’s scientists of old were aware that science is a process. They understood that innovation is underpinned by knowledge of what happened before, and were voracious consumers of knowledge from ancient Greece, for example. Today, knowledge of the latest research is found in Europeanlanguage scientific journals. In Muslim countries, only a few elite universities have good access to the top journals, and translations from European languages into Arabic are pitifully rare.

Lack of encouragement for critical thinking is also a big factor. Scholarly debate and criticism flourished in the old Muslim world: it was possible to publish many things which today would result in an appointment with the censor – or even prison or exile. High-quality research needs a level of freedom to think, speak and publish that does not exist in many Muslim countries.

Commitment to a faith can be a strong catalyst for scientific excellence, but perhaps the overriding message of 1001 Inventions is that the freedom to push boundaries and to challenge dogma is an irreplaceable ingredient.

By Ehsan Masood, published in New Scientist

Ehsan Masood is a writer specialising in science in developing countries. See www.1001inventions.com for further information on the exhibition

Download full article here

Ibn al-Haytham (10 to 11th century A.D.)

The turn of the first millennium was a time of intense research in mathematics, physics, and astronomy. One scientist active and productive in all of these fields was Ibn al-Haytham, called by his successors of the 12th century “Ptolemy the Second.”

Ibn al-Haytham, also known as Alhazen (the Latin transliteration of his first name al-Hasan), was born in Iraq, most likely in Bassorah, in the second half of the 10th century. He arrived in Cairo under the reign of Fatimid Caliph al-Hakim, a patron of the sciences who was particularly interested in astronomy. Ibn al-Haytham proposed to the Caliph a hydraulic project to control the flow of the Nile—an early Aswan dam. The Caliph refused, but al-Haytham continued to live in Cairo, in the neighborhood of the famous University of al-Azhar, until his death after 1040.

Ibn al-Haytham was born after a century and a half of intense research in mathematics, astronomy, optics, and other physical sciences. Scholars such as Banu Musa, Thabit ibn Qurra, Ibrahim ibn Sinan, al-Quhi (1), and Ibn Sahl measured curved surfaces and solids, invented new geometrical methods, and rediscovered the method of integral sums. They combined mathematical and observational astronomy and formulated the first rigorous geometrical theory of lenses.

Beyond the biographic details above, little is known about Ibn al-Haytham’s life. But his contribution to science is not in doubt. His work on optics, which includes a theory of vision and a theory of light, is considered by many to be his most important contribution, setting the scene for developments well into the 17th century. His contributions to geometry and number theory go well beyond the archimedean tradition. And by promoting the use of experiments in scientific research, al-Haytham played an important part in setting the scene for modern science.

The ancient bibliographers cite at least 96 scientific titles under al-Haytham’s name; more than 50 survive. Half of his writings are on pure mathematics; 14 on optics, including the authoritative and voluminous Kitab al-Manazir (Book on Optics) (2–4); and 23 on astronomy. He also wrote about philosophy of mathematics, statics, hydrostatics, and various other topics, grappling with all mathematical sciences of his time except algebra.

Few mathematical and scientific writings in the Middle Ages have been as influential as those of Ibn al-Haytham, whose works were translated into Latin, Italian, and Hebrew. The Latin translation of his Book on Optics and On Parabolic Burning Mirror provided a basis for centuries of research in optics. His mathematical works influenced Roger Bacon, Frederick of Fribourg, Kepler, Snell, Descartes, and Huygens and many others.

In one of his many geometrical studies, al-Haytham calculated the volume of solids such as the paraboloid and the sphere. He used the method of integral sums and generalized one of the propositions in Euclid’s Elements. In another study, he set out to prove that among planar figures with the same perimeter, the disk has the greatest area, and among solids with the same total surface the sphere has the greatest volume. To study these problems, Ibn al-Haytham formulated the first known theory on solid angle, which leads to double integrals (1, 3). It was the most advanced mathematical work of his time, combining a projective method and an infinitesimal method.

Some of Ibn al-Haytham’s most important geometrical writings deal with the theory of conic sections. Apollonius’ Conics, written in the 3rd century B.C.E., were translated into Arabic in the 9th century A.D., but the last (the eighth) book had long been lost in the original Greek. Ibn al-Haytham devoted a substantial treatise to the reconstruction of this lost book. He also used conic sections to construct solid figures known since antiquity, such as the regular heptagon, as well as new ones (1).

Earlier mathematicians had concentrated on isolated problems of geometrical construction. Ibn al-Haytham showed that geometrical figures could be built systematically with the help of intersections of conic curves, and that these curves could be constructed from in a pointwise fashion and could also be drawn continuously. His studies of pointwise geometrical transformations led him to introduce the notion of continuous movement into geometry. He went on to develop the first concept of space based on geometry (1).

Ibn al-Haytham redirected geometrical research and obtained many results attributed by historians to his successors of the 17th century. But his work in optics was no less revolutionary. He changed the meaning of the term optics, and established experiments as the norm of proof in the field. The revolution entailed his division of optics into two parts: a theory of vision and the associated physiology of the eye and psychology of perception, and a theory of light that includes geometric and physical optics.

There had been a doctrinal contest between “extramissionists,” who postulated a visual ray produced by the eye, and “intromissionists,” who held that objects sent off forms or totalities that emanated from the visible under the effect of light. Ibn al-Haytham proposed instead that rays emanate toward the eye from every point of a visible object. Looked at thus, the eye becomes a simple optical instrument. Ibn al-Haytham then explained how the eye perceives the visible with the help of the rays emitted from all points.

His optical theories rested on qualitative laws and quantitative rules derived from experiments, which he performed with an instrument that he designed and built himself. On the basis of these experiments, al-Haytham was the first to propose a camera obscura. He also discovered spherical aberration, and gave the correct explanation of the moon’s light. Henceforth, experimental control was viewed not only as a general practice of investigation but as the norm of proof in optics, and more generally in physics.

By Roshdi Rashed, published in Science  02 Aug 2002: Vol. 297, Issue 5582, pp. 773 DOI: 10.1126/science.1074591

References

1. R. Rashed, Les Mathématiques infinitésimales du IXe au XIe siècle (al-Furqan Islamic Heritage Foundation, London, 1993 to 2002), vol. 4.
2. M. Nazif, Al-Hasan ibn al-Haytham, Buhuthuhu wa kushufuhu al-basariyya (Nuri Press, Cairo, 1942 to 1943), vol. 2.
3. R. Rashed, Ed. Encyclopedia of the History of Arabic Science, 3 vols (Routledge, London/New, 1996).
4. A. I. Sabra, The Optics of Ibn al-Haytham: Books I-III on Direct Vision (Warburg Institute, London, 1989).

Ibn Rushd (1126—1198), was a native of Cordoba, in Andalusian Spain, and his work covered a broad range of topics in medicine, science and philosophy. He would be known to Thomas Aquinas and other European scholars in the next century as Averroes. And Ibn Rushd was—thanks to Aquinas—destined to have a much greater impact on the European mind than he ever did on Islamic culture.

First, a little context:

The wanderers who came to Spain and Sicily from Italy, France, the British Isles in the 11th and 12th centuries, did not know it at the time, but their rediscovery of scientific and medical treatises, would, long before Gutenberg and the printing press, lead to Europe’s first information revolution.

This revolution was triggered in no small part by a simple demand: for better technology. Or more precisely, a demand for better instructions on how to use technology.

Especially the tools of astronomy.

These tools included carefully written tables with precise recordings of celestial movements, and books of planetary theory—the most important of which was the great work of Claudius Ptolemy: The Almagest.

If you were a monk in France or Italy, intent on projecting the most accurate dates of each year that Easter and other holy days should fall, the only way to get your hands on the most reliable copies of these texts, meant finding a good translation from Arabic (or Greek).

And the only way to acquire these … was to hit the road.

Such was the origin of the medieval ‘translation movement’, an enterprise that largely took place in Spain and in Sicily between the years 1130 and 1275.

But what started out as a search for better translations of astronomical and astrological guides, led first to the discovery of Arabic treatises on the astrolabe and the astronomical tables of the great Muslim astronomer al-Kwarzimi who worked in Baghdad in the ninth century.

This led in turn to the discovery of other Arabic textbooks on medicine, philosophy and science by figures such as Ibn al-Haythem and al-Biruni.

As Arab philosophers and doctors had long adopted the ancient works of Aristotle, scholars from Europe found themselves rediscovering the Greek philosopher’s source texts as well, source texts that for centuries they had only known from references in other works that merely summarized them—and often not accurately.

Back to our hero: Ibn Rushd was writing at the height of this translation movement, although he never came in contact with the scholars in the northern cities of Spain, lately recaptured by Christian dukes.

Born in 1126, Ibn Rushd came from a prominent family of judges in Cordoba. He was educated as a physician, but felt strongly drawn to the study of pure philosophy.
A fortuitous meeting with the Caliph of Cordoba, Abu Ya’qub Yusuf, led to a full time position for the young doctor. Yusuf also enjoyed the study of philosophy in spite of the more conservative attitude that the Almohad dynasty had toward the subject, and he employed Ibn Rushd to write new commentaries on Aristotle to clarify all the major works. Many had been previously translated into Arabic from earlier Syriac versions, but Yusuf found them difficult to understand.

This period, the last quarter of the twelfth century, was the time in which Ibn Rushd wrote his most influential treatises, adopting a rationalist point of view—not unlike the view (I discussed recently here) propounded by Adelard of Bath and William of Conches—that would have such profound influence on the pursuit of science in the later Middle Ages–namely, that nature operated according to its own autonomous laws, and that these laws could be fruitfully explored in their own right.

After the death of Abu Ya’qub Yusuf, the Caliph’s son al-Mansur continued to support Ibn Rushd for a few years, but by the 1190s, more conservative members of the Islamic schools began to attack the philosopher, and on the excuse of some questionable charges made against him, Ibn Rushd was, at the age of 69, banished from Cordoba to the nearby village of Lucena.

Though he did not suffer execution, his books were banned, and indeed most were eventually burned—though not all. He was allowed to return to Cordoba, one year before he died in 1199 when he was 73. But he was not destined to have anything like the influence on Islamic thought that earlier masters such as Ibn Sina and al-Ghazali had.

Ibn Rushd was never to know the honor and esteem in which his works would be held by his country’s enemies to the north of the Pyrenees. When Aquinas wrote his Summa Theologica in the latter half of the thirteenth century, he referred to Ibn Rushd as “The Commentator.” When it came to any discussion of Aristotle, Aquinas rarely failed to reference Ibn Rushd’s assessment of any question—even when he disagreed with it.

The Latin Christians, for example, believed Ibn Rushd espoused a doctrine of ‘double-truths’, whereby philosophy and theology allow one to adopt two contradictory positions, for example about the eternity of the universe. This was roundly condemned.

But as it turns out, the source of this assessment of Ibn Rushd was based on a faulty understanding, due to a lack of access to his complete works.

One of the main reasons that led to such a deep misunderstanding, Nidhal Guessoum writes in the introduction to his book Islam’s Quantum Question, is the simple fact that two of the three books that contained Ibn Rushd’s essential views were never translated into Latin or later to European languages until the twentieth century. “Only his commentaries on Aristotle’s and other great Hellenistic works were known to the West until recently.”

There’s another twist to this tale as well.

As historian Diarmaid MacCulloch notes in his book Christianity: the First Three Thousand Years:

Scholasticism was disputatious, skeptical, analytical, and that remained characteristic of Western intellectual exploration long after most Western intellectuals had parted company with scholasticism itself. And it had its precedent in the method used in Islamic higher education. It is a happy irony that one of the great expressions of the cultural unity of the Latin West, evolved at the age of the Crusades, had its roots in the culture which the West was trying to destroy.” [p. 399]

For an excellent short biography of Ibn Rushd, check out Averroes, written in 2001 by Majid Fakhry, Emeritus Professor of Philosophy at the American University of Beirut.

By John Farrell, published in Forbes, June 30^th 2014.

Follow me on Facebook and Twitter. Subscribe to my Vimeo Channel.

The first heritage regrouped the savoir-faire, often ingenious, that were practised and transmitted, orally and on initiation in the world of corporations, particular professions or activities. This was the case of the knowledgeable who dealt with generally, by commodity, to be classed in the following groups: military or civil technology (water based systems, automations), chemistry (treatment of glass and colours, cosmetics, metal works), administration and calculations for transactions, geometry, land surveying and decoration etc. The comparative study of these methods and techniques reveals the diversity of their origins and their links with different cultures in which they occurred.

The second heritage comprises of the theories or applications of knowledge which have been preserved and circulated in writings. They were produced generally in Greece, India, Persia, Mesopotamia and to a lesser extent the Iberian peninsula. The results of their enquiries have not been the same all over: a great part of Greek sciences were hypothetically deduced, those of India, Persia and Mesopotamia were due to algorithmic and experimental methods.

This diversity had the same goal, that of establishing the results and making tools, characteristic of the first scientific footsteps in Islamic countries were disparate elements of knowledge coming from diverse cultural horizons, having firstly been juxtaposed before making the object arising from a prolific amount of suggestions and giving a unified expression across the Arab world. It is also from the IX century, that a network of scientific establishments were set up, in towns such as Baghdad and Damascus at the centre of the Empire, Samark and in central Asia, Kairouan au Maghreb abd Cordoba in the Iberian peninsular. From the end of the X century, its centres would come together with others, all just as dynamic, such as Rayy in Iran, Cairo in Egypt and, a little later, Toledo, Saragossa and Marrakech in the Muslim East. It is important to remember that, in all these centres, science was practised in the same fashion, according to a norm that you could describe as “universal”, that is to say did not depend on any specific denomination, ethnic or cultural identity, apart from the unity of the language of expression, that we have already evoked, and that is the only justification for the mode of expression of “Arabic science” to design this together in practice.

After a period of more than a century where this was known, from the first heritage, which was to work in different sectors of activity in the Islamic city, the need to access the contents of the second heritage, starting by formulating and improving some of the first translations, which were financed by the caliphs and other high persons of the State. But, from the end of the IX century, these initiatives experienced a great amplification –right through to the middle of the X century- carried by civil members of the society not necessarily belonging to the courts of caliphs and princes. As this society was cosmopolitan, multi-denominational and multi-cultural, it is not surprising that this long-time activity of translation reflecting its diversity (even if the Arabic libraries note the strong participation of the Christian communities increasingly in the activity of translation). It must, finally, be added, about this phenomenon, that its duration is explained by the development, in certain groups of society, of a real demand. The member of these groups were generally less well off than the patron caliphs but relatively more numerous. Amongst them, it is interesting to note the presence of eminent scientists such as al-Kindi (died circa 873) and the brothers Banû Mûsâ (IX century).

These translations concern all the scientific and technical domains as were practised in the previous civilisations: astronomy and Indian medicine written in Sanskrit or Persian writings in pehlevi, texts in Latin dealing with astrology and medicine, treatises of nabatéen agriculture. . . To this modest amount, you must add, much more importantly, produced within the framework of Greek scientific and philosophical tradition since the V century B.C. It is this material, which after translation, has added to or impregnated all the disciplines practised in Islamic countries, even those who have originated contributions to the new civilisation. There was, in the first place, mathematicians, with their different orientations, which were designed from the end of the III century: numerical theories with Pythagoras and Nikomacheia, plane and cubic geometry of Euclid, conic geometry with Apollonius, and geometry of measurement with Archimedes. In close relation with his disciples, he also studied astronomy, (models of planets, astronomical tables, instruments for measuring) and physics (statics, hydrodynamics, optics). At the time there was all the sciences as one considered them as not Arts; Greek heritage: medicine (physiology, anatomy, pharmacopaeia), mechanics (ludic or utilitory) chemistry (experimental or esoteric), botany, zoology, agriculture, etc.

As the discoveries and innovations in this book unfold themselves, they are divided into six categories, it seems practical to describe them, briefly, the development of each one is placed in order to show its original contribution which is the object of this book to show the general development of the science to which they refer.

Mathematics started off in Islamic countries, from its practical aspects, which refer to the different economic needs (accounting, commercial transactions), justice (division of inheritances) and arts (architecture, decorations). Some ancient chapters have been reactivated, such as the procedures for mental calculation, the Indian arithmetical procedure based on the system of positional numbers (with the zero), geometry tools to make the architectural shapes and to copy the figures in two dimensional decorations. It is within this frame-work that they have valued and perfected the geometric steps and techniques (symmetry, rotations, calligraphy, and that of the mosaic).

The second great orientation of mathematics is purely theoretic in the sense where the researchers wanted to solve problems that their Greek predecessors had stumbled on or new problems that they had been set, or other sciences had asked them to solve. Sharing the results and the steps that were inherited from the Ancients, they started off by commenting on them, sometimes criticising them, then reflecting on the foundations of their discipline, to elaborate on the thesis, before developing them in new ways. Certain ones, as algebra and trigonometry, were extensions and enrichments of old practices. Others, as combination analysis and magic squares were suggested then favoured by a cultural context.

From the start, astronomy had the attention of the State. Certain caliphs not only financed the translations but also made certain orders to the leading astronomers: the compiling of calendars and geographical maps, the determination of the direction of Mecca, calculation of the times for everyday prayers. Always in response to the needs, this time in response to particular people (merchants, pilgrims, men of science), interest in ancient instruments (planispheric astrolabes, solar bodies) which were redressed and perfected, such as was described in the chapter “ from al-Khwârizmî to al-Zarqâlî, the astrolabe became the king of instruments”. Later, and in the scope of optimisation (lightening instruments) new instruments were invented (the universal astrolabe, sines).

But astronomy had had an important theoretical wing that one knew less and had perhaps constituted a decisive stage in the development of this discipline, even across some of its checks. In this domain, the work concerned the realisation of numerous astrological tables for all uses, the conception of models of new planets to replace those of Ptolemy which, which having reigned for centuries in astronomy were no longer considered as satisfactory. They even had, at the beginning of the XI century, in central Asia, discussions on the theory of the Earth’s rotation on its axis and that of its rotation around the sun. These hypothesises were finally abandoned, not for theological or philosophical reasons, but for reasons judged as scientific in their time.

In physics, and in an extension of Greek traditions, four disciplines were particularly developed: statics, dynamics, hydro-dynamics and optical. Three of the contributions as presented in this book illustrate the vitality of these domains: the scales of wisdom of al-Khâzinî (XII century), the theory of light of Ibn al-Haytham (died 1041) and the rainbow theory of al-Fârisî (died 1319). It is important to state that the contributions were not the end of the investigations that had started, for certain among them, at the start of the IX century. To take for example optics, the sources we learn first researched concerned mirrors, which interested first of all the military, because they could be used to start fires and so burn the fleets and fortresses of the enemy. Then there were the theoretical preoccupations on the technical aspects. Led by al-Kindî, Ibn Sahl (X century) and their two successors; these studies concerned the physiology of optics, the laws of reflection and refraction and certain light phenomena that can be seen in the sky.

Arab medicine, solidly anchored in the galénic medical tradition, seems to have had trouble to free itself from its ancient conceptions and convictions. But this did not impede the innovation in certain other domains. Its most significant contribution, by amplitude and duration, has been the setting up of a medical hospital, financed firstly by State representatives then by members of the society with the help of waqf (Assets belonging to the state that can’t be sold). Certain of these hospitals even had sections for the mentally ill. They also had advances in anatomy (knowledge of certain bones in the human body), in the diagnosis of certain illnesses, in the practice of surgical instrumentalisation, in particular with the contribution of Andalusian az-Zahrâwî (XI century), and in the elaboration of great medical synthesis, such as those of Ibn Sîna (Avicenne, died 1037) and of ar-Râzî (Rhazes, died 935), who directed medical teaching in Europe until XVIIth century. But it was in physiology, with the discovery of the small circulation of blood, which is described in the chapter “the discovery of pulmonary circulation by Ibn al-Nafîs”, that a new road was followed. Unfortunately, this was abandoned by the medical community of the era (XIII century) which stayed faithful to the Galien theory, confirmed by Avicenne.

In mechanics, it was in response to civil and military needs that the works of Héron of Alexandria, Archimedes, and Philon de Byzance were translated into Arabic. After having adapted and perhaps bettered their contents the Islamic countries’ mechanics set out to innovate, in particular automations and hydraulic systems. It is in this last domain that they updated and applied the conical valve, the camshaft, the piston and the crankshaft. Certain original ideas were already thought up in the book of the brothers Banû Mûsâ. But it was with al-Jazarî (died in 1206) that you hear the most numerous and significant innovations, as those that we presented here, in the chapter “the al-Jazari (hydraulic) water pump”.

Chemistry with medicine is the discipline, which, it appears, the best to survive the decline of the ancient civilisations of the eastern Mediterranean. This explains its precocious reactivation in the sphere of the new civilisation. in effect, from the start of the VIII century, it has assisted with the constitution of a solid tradition in this domain with, as the undisputable animator, the famous Jâbir Ibn Hayyân (Geber), whose works together with those of his disciples, abound in original results. after them, different chemical practices were developed, such as calcination, sublimation, purification, and above all distillation, which had substantial progress, as is shown in the chapter “Introduction to Arab alchemy”. Always in the framework of the theory of the four elements inherited from the Greeks and refined by Jâbir, these works added to the description of substances not previously known about, the setting up of mineral acids and the elaboration of new classifications of analysed products. Among the scientists who have taken part in these advances are al-Kindî and Abû Bakr ar-Râzî.

One part of the contributions that we are going to present briefly has started to circulate, relatively quickly, outside the borders of Islamic countries, in particular towards Europe. The figures called “Arabic” and the astrolabe arrived in the south of Europe at the end of the X century. Some works of medicine published in Baghdad and at Kairouan have been transcribed in Latin by Constantine the African in the second half of the XI century. But you have to wait until the start of the XII century for this activity of translation (from Arabic to Latin and Hebrew) to grow. At Toledo and Palermo, where this phenomenon had its seat, dozens of young Europeans freshly ‘arabised’ were engaged in this with a passion, supported and financed by enlightened men of the church and, later, by the Castilian king Alphonse X the wise. Their work allowed access for men of science and practitioners to the rich inheritance in origin Greek, Indian and Arab cultivated and elaborated on in the Muslim world since the IX century. The assimilation of these rich contents opened the way to new investigations which were, in their turn, contributions to modern day science.

In conclusion, it remains for us to make a few remarks on the nature of the scientific activities of Islamic countries, in the sphere of which the discoveries presented here have been realised, and on the actual gateway of these discoveries.

It should be first of all stated that as the scientific practices which are going to be briefly described here, during each of their phases, in a context of intercultural exchanges, which are never contradicted. The scientific historians have even observed the totally non religious character of these practices, which may be at the level of their contents, of their formation, of their approach, or discussion which has been produced on the scientific production itself. This aspect only serves to reinforce the universality of the science produced in Islamic countries, favouring, just the same, their circulation in Muslim cultures and in Christian cultures of medieval Europe, and this in spite of the religious antagonisms that are sometimes expressed from the advent of Islam and which are deepened from time to time, particularly, at the time of the crusades (end XI – end XII centuries).

As to the discoveries presented here, they are certainly constituted on a time, largely well passed, in the elaboration of science. But they are more than that. In effect, by the motivations which have animated their authors, by their approaches and their goals that they have met, they witness, further than the specificity of each of them, from what appears to men of science from different eras and cultures: an instant curiosity, patient observation of studied phenomenon, taking things into account, with a critical attitude, in relation to your predecessors, obstinate research of the truth, comforted by the unbreakable faith in the capacities of science to surpass all obstacles. It is this lesson, finally very modern and universal, that the authors of this book have read in the contributions of some of these Islamic savants, and that they want to render it accessible to the teachers and their pupils.

Ahmed Djebbar

Download The Dicsoveries in Islamic Countries by Ahmed Djebbar

Photo Credit

Courtesy of Younes Boudiaf, TIKUYA PRODUCTIONS

https://www.facebook.com/younes.boudiaf

https://twitter.com/younesboudiaf

By Ehsan Masood

As we celebrate Darwin, let’s not forget the unsung champions of evolution from the Muslim world

Last month, scientists from around the world partied into the small hours on the 200th anniversary of the birth of Darwin.

But as we celebrate the work of one of the most influential scientists ever, let’s take a moment or two to remember others who contributed ideas in the history of evolutionary thought. Many came from Britain as well as other countries in Europe. Others came from further afield, and their writings are increasingly coming to light thanks to the painstaking work of historians of science, and historians of ideas.

One of them is an East African writer based in Baghdad in the 9th century called al-Jahiz. In a book describing the characteristics of animals, he remarked:

“Animals engage in a struggle for existence, and for resources, to avoid being eaten, and to breed.” He added, “Environmental factors influence organisms to develop new characteristics to ensure survival, thus transforming them into new species. Animals that survive to breed can pass on their successful characteristics to their offspring.”

Or there’s Muhammad al-Nakhshabi, a scholar from 10th century central Asia. He wrote: “While man has sprung from sentient creatures [animals], these have sprung from vegetal beings [plants], and these in turn from combined substances; these from elementary qualities, and these [in turn] from celestial bodies.”

In their excellent Darwin’s Sacred Cause: Race, Slavery and the Quest for Human Origins, Adrian Desmond and James Moore describe how Darwin and his family were influenced by the anti-slavery movement, and they explore the extent to which these ideas, in turn, influenced his own thinking – especially on the idea of the connectedness of humanity.

A parallel line of argument can also be found from a Spanish philosopher from the 12th century. His name is Muhammad ibn Arabi and he developed an idea that his translators called the “unity of existence”. He believed that all living matter is connected. And many commentators now think that this was his way of showing that within humanity, there can be no outsiders or “others”.

These ideas were later taken up in the writings of Indian-born philosopher-poet Muhammad Iqbal in the early 20th century. We also know that Iqbal had been reading Darwin and wanted to find a way of synthesising the latest ideas from biological science with earlier Islamic-era philosophy. Iqbal today is revered throughout South Asia and also happens to be Pakistan’s national poet.

Why is it important to emphasise links between Darwin, and thinking on evolution in other cultures?

One reason is that in many developing countries today, Darwin – and by extension evolution – are seen as being in the service of imperialism. This is partly because of the period in which Darwin lived and worked, but also because of a perception that Darwin’s ideas were used by colonialists to provide “scientific” justification for empire.

Another reason comes from the rise of creationism. I’ve just finished work on a new documentary series for BBC radio 4 on science and Islam in the modern world. One thing I didn’t expect to find was the extent to which creationism poses a risk to what is otherwise more encouraging news: that after decades of neglect, interest and investment in science and learning in Islamic countries is on an upward trajectory.

Many countries are building more universities and opening doors for young people to embark on PhDs. Progress, however, will be slower if more start believing that scientific knowledge can be found in the pages of sacred texts; or if they devote time and energy getting sucked into anti-evolution campaigns.

Instead, if today’s young scientists could just take a peek into the history of science in Islamic cultures, they would see a respectable tradition of thinking, debate and argument on the origins of life and the evolution of species.

The irony in all this is that creationism did not exist as a significant movement during the heyday of Islamic civilisation. Back when Baghdad was a centre for advanced learning, scientists did not spend hours examining passages of revelation to see if they compare with observed knowledge of the natural world.

Instead, they went out and tried to discover things for themselves.

Islam and Science is on BBC Radio 4 at 9pm on Monday 2 March. It is also available to download on BBC i-player.

By Ehsan Masood, published in The Guardian, March 1st 2009.

Interest in optics began in antiquity. The Babylonians, Egyptians and Assyrians all used polished quartz lenses. The basic principles of geometric optics were laid down by Plato and Euclid. They included ideas such as the propagation of light in straight lines, and simple laws of reflection from plain mirrors. The earliest serious contribution from the Islamic world came from ninth-century Arab scholar Ya’qub ibn Ishaq al-Kindi.

As a young man, Ibn al-Haytham received an excellent education and was widely noted as a mathematical and scientific prodigy. Frustrated by his administrative duties working in a government post in the vast Islamic Empire — which at the time stretched from India to Spain — he was sacked owing to real or, as some speculate, faked mental illness.

Sometime during the first decade of the new millennium, he proposed an ambitious project to dam the Nile. He was invited to Egypt by the Fatimid caliph al-Hakim bi’amr Illah. However, on seeing the scale of the task, Ibn al-Haytham quickly realized that it was beyond him. He was promptly imprisoned in Cairo for wasting the caliph’s time.

Far from cowing him, the decade of imprisonment granted Ibn al-Haytham the seclusion to think and write, particularly on optics. After his release around the year 1020, he began working at a prolific rate, carrying out a series of famous experiments on the nature of light. For example, using a camera obscura, he proved that light travels in straight lines; he also mathematized the fields of catoptrics (reflection of light by mirrors) and dioptrics (refraction of light through lenses). This huge body of experiment and theory culminated in his Book of Optics.

This treatise can be regarded as a science textbook. In it, Ibn al-Haytham gives detailed descriptions of his experiments, such as exploring how light rays are reflected off plain and curved surfaces. He includes the apparatus he used, the way he set it up, the measurements and his results. He then uses these observations to justify his theories, which he develops with geometrical models. He even urges others to repeat his experiments to verify his conclusions. Many historians of science consider Ibn al-Haytham to be the first true proponent of the modern scientific method.

The work can be roughly divided into Books I, II and III, devoted to the theory of vision and the associated physiology of the eye and the psychology of perception; and Books IV to VII, covering traditional physical optics. The work’s most celebrated contribution to science is its explanation of vision.

At that time, scholars’ understanding of the phenomenon was a mess. The Greeks had several theories. In the fifth century bc, Empedocles had argued that a special light shone out of the eye until it hit an object, thereby making it visible. This became known as the emission theory of vision. It was ‘refined’ by Plato, who explained that you also need external light to see. Plato’s student Aristotle suggested that rather than the eye emitting light, objects would ‘perturb’ the air between them and the eye, triggering sight. Other philosophers around this time, including Epicurus, attempted a form of ‘intromission theory’ of vision (light entering the eye from outside), but it was Plato’s theory that was given a mathematical basis by Euclid, who described light rays emerging in a cone from the eye. Several centuries later, Ptolemy expanded on this idea.

Early Islamic scholars such as al-Kindi and Hunayn ibn Ishaq favoured a combined emission–intromission theory. They posited that the eye sends out light to the observed object, which then reflects the light back into the eye.

It took the genius of Ibn al-Haytham to finally resolve the issue. He argued that if we see because rays of light are emitted from the eye onto an object (Plato and Euclid’s ‘sight rays’), then either the object sends back a signal to the eye or it does not. If it does not, how can the eye perceive what its rays have fallen on? Light must be coming back to the eye, and this is how we see. But if so, what use is there for the original rays emitted by the eye? The light could come directly from the object if it is luminous or, if it is not, could be reflected from the object after being emitted by another source. Rays from the eye, decided Ibn al-Haytham, are an unnecessary complication.

He also went further than anyone before in trying to understand the underlying physics of refraction. He argued that the speed of light was finite and varied in different media, and he used the idea of resolving the path of a light ray into its vertical and horizontal components of velocities. He carried out all his work geometrically, and introduced many new ideas, such as the study of how the atmosphere refracts light from celestial bodies.

Later Islamic scholars, including the thirteenth-century Persians Qutb al-Din al-Shirazi and Kamal al-Din al-Farisi, extended the Optics. Al-Farisi, who wrote The Revision of the Optics (Tanqih al-Manazir), used geometry to arrive at the first correct mathematical explanation of the rainbow (at the same time as, but independently of, the German scholar Theodoric of Freiberg).

“Many historians of science consider Ibn al-Haytham to be the first true proponent of the modern scientific method.”

The Book of Optics was first translated into Latin in the late twelfth or early thirteenth century, as De Aspectibus. The English philosopher and empiricist Roger Bacon then wrote a summary of it, as did his Polish contemporary Witelo. It was soon being cited across Europe. Among the many ideas taken up by Ibn al-Haytham’s Latin-reading disciples was that pure light was not visible, and that its job was simply to allow us to see colour. Even Kepler, who studied Ibn al-Haytham’s work, thought this; it took Newton to describe light as itself being made up of different colours. (Other erroneous ideas in Optics include a repetition of Ptolemy’s mistaken law of refraction, and an incorrect understanding of reflection as a more intense form of refraction.)

Ibn al-Haytham’s work decisively influenced the theory of perspective that flowered in Renaissance European science and art. De Aspectibus was translated into Italian in the fourteenth century, making it accessible to practitioners such as the Florentine art theorist and architect Leon Battista Alberti, author of the 1435 treatise On Painting (Della pittura), the sculptor Lorenzo Ghiberti and the geometer-artist Piero della Francesca. They harnessed Ibn al-Haytham’s discussions on perspective to help to create the illusion of three-dimensional depth on canvas and in friezes. These revolutionary artists strove to understand both the objective world and the visual system that determined its appearance.

Today, as we use laser beams to manipulate atoms, stimulate neurons with light or convey information in entangled photons, it is worth recalling that the foundations of this field were laid down around 1,000 years ago by Ibn al-Haytham.

By Jim Al-Khalili, published in Nature, February 11th 2015.

I review first the main similarities and differences between the planetary model of Ibn al-Shatir (14^th-Century Muslim astronomer) and of Copernicus. I show that important similarities reside in the technical aspects of the orbits constructed by the two astronomers but that fundamental differences are:

(a) Copernicus adopted a heliocentric model while Ibn al-Shatir (and all Muslim astronomers) assumed a geocentric model, as strictly as possible;

(b) Copernicus followed a clear inductive method while Ibn al-Shatir remained within the Zij (astronomical tables) tradition.

On the question of the extent to which Copernicus had benefitted from the ‘transmission’ of thos models and critiques of Ptolemy, I insist that neither Ibn al-Shatir nor any Muslim astronomer accepted, let alone proposed, a heliocentric model. I then briefly discuss the Copernican Revolution and try to assess the extent to which the Polish astronomer might have been influenced by earlier Muslim discussions on the centrality (or not) and immobility (or possible motion) of Earth.

Nidhal Guessoum is associate dean at the American University of Sharjah. He can be followed on Twitter at: www.twitter.com/@NidhalGuessoum

Source: http://adsabs.harvard.edu/full/2008Obs…128..231G

Download full article here – Courtesy of Nidhal Guessoum

But in fact, Yemen is where the ubiquitous brew has its true origins.

Along with the first university, and even the toothbrush, it is among surprising Muslim inventions that have shaped the world we live in today.

The origins of these fundamental ideas and objects — the basis of everything from the bicycle to musical scales — are the focus of “1001 Inventions,” a book celebrating “the forgotten” history of 1,000 years of Muslim heritage.

“There’s a hole in our knowledge, we leap frog from the Renaissance to the Greeks,” professor Salim al-Hassani, Chairman of the Foundation for Science, Technology and Civilisation, and editor of the book told CNN.

“1001 Inventions” is now an exhibition at London’s Science Museum. Hassani hopes the exhibition will highlight the contributions of non-Western cultures — like the Muslim empire that once covered Spain and Portugal, Southern Italy and stretched as far as parts of China — to present day civilization.

STORY HIGHLIGHTS

• Exhibition celebrates 1,000 years of “forgotten” Muslim heritage
• From coffee to cranks, items we couldn’t live without today are Muslim inventions
• Modern hospitals and universities both began in 9th century North Africa

Here Hassani shares his top 10 outstanding Muslim inventions:

1. Surgery

Around the year 1,000, the celebrated doctor Al Zahrawi published a 1,500 page illustrated encyclopedia of surgery that was used in Europe as a medical reference for the next 500 years. Among his many inventions, Zahrawi discovered the use of dissolving cat gut to stitch wounds — beforehand a second surgery had to be performed to remove sutures. He also reportedly performed the first caesarean operation and created the first pair of forceps.

Hospitals as we know them today, with wards and teaching centers, come from 9th century Egypt
~ professor Salim al-Hassani

2. Coffee

Now the Western world’s drink du jour, coffee was first brewed in Yemen around the 9th century. In its earliest days, coffee helped Sufis stay up during late nights of devotion. Later brought to Cairo by a group of students, the coffee buzz soon caught on around the empire. By the 13th century it reached Turkey, but not until the 16th century did the beans start boiling in Europe, brought to Italy by a Venetian trader.

3. Flying machine

“Abbas ibn Firnas was the first person to make a real attempt to construct a flying machine and fly,” said Hassani. In the 9th century he designed a winged apparatus, roughly resembling a bird costume. In his most famous trial near Cordoba in Spain, Firnas flew upward for a few moments, before falling to the ground and partially breaking his back. His designs would undoubtedly have been an inspiration for famed Italian artist and inventor Leonardo da Vinci’s hundreds of years later, said Hassani.

4. University

In 859 a young princess named Fatima al-Firhi founded the first degree-granting university in Fez, Morocco. Her sister Miriam founded an adjacent mosque and together the complex became the al-Qarawiyyin Mosque and University. Still operating almost 1,200 years later, Hassani says he hopes the center will remind people that learning is at the core of the Islamic tradition and that the story of the al-Firhi sisters will inspire young Muslim women around the world today.

5. Algebra

The word algebra comes from the title of a Persian mathematician’s famous 9th century treatise “Kitab al-Jabr Wa l-Mugabala” which translates roughly as “The Book of Reasoning and Balancing.” Built on the roots of Greek and Hindu systems, the new algebraic order was a unifying system for rational numbers, irrational numbers and geometrical magnitudes. The same mathematician, Al-Khwarizmi, was also the first to introduce the concept of raising a number to a power.

6. Optics

“Many of the most important advances in the study of optics come from the Muslim world,” says Hassani. Around the year 1000 Ibn al-Haitham proved that humans see objects by light reflecting off of them and entering the eye, dismissing Euclid and Ptolemy’s theories that light was emitted from the eye itself. This great Muslim physicist also discovered the camera obscura phenomenon, which explains how the eye sees images upright due to the connection between the optic nerve and the brain.

7. Music

Muslim musicians have had a profound impact on Europe, dating back to Charlemagne tried to compete with the music of Baghdad and Cordoba, according to Hassani. Among many instruments that arrived in Europe through the Middle East are the lute and the rahab, an ancestor of the violin. Modern musical scales are also said to derive from the Arabic alphabet.

8. Toothbrush

According to Hassani, the Prophet Mohammed popularized the use of the first toothbrush in around 600. Using a twig from the Meswak tree, he cleaned his teeth and freshened his breath. Substances similar to Meswak are used in modern toothpaste.

9. The crank

Many of the basics of modern automatics were first put to use in the Muslim world, including the revolutionary crank-connecting rod system. By converting rotary motion to linear motion, the crank enables the lifting of heavy objects with relative ease. This technology, discovered by Al-Jazari in the 12th century, exploded across the globe, leading to everything from the bicycle to the internal combustion engine.

10. Hospitals

“Hospitals as we know them today, with wards and teaching centers, come from 9th century Egypt,” explained Hassani. The first such medical center was the Ahmad ibn Tulun Hospital, founded in 872 in Cairo. Tulun hospital provided free care for anyone who needed it — a policy based on the Muslim tradition of caring for all who are sick. From Cairo, such hospitals spread around the Muslim world.

For more information on muslim inventions go to: muslimheritage.com. For more information about the exhibition at London’s Science Museum go to: science museum.org.uk

By Olivia Sterns for CNN January 29, 2010.

For more than a century an army of scholars, enthusiasts and outright eccentrics has delved into the question of who discovered America. Some of the claims are truly exotic, with fanciful reportage on ancient Phoenicians in Rhode Island or Chinese from the Middle Kingdom in the Bay Area. Back in the 1950s the colourful Norwegian ethnographer and adventurer Thor Heyerdahl contended that Peruvians in sailboats made of balsa wood were commuting back and forth between the Americas and Polynesia centuries before Columbus set sail.
Leaving aside patently absurd theories, there are a number of serious­ claimants for the title. First comes Zuan Chabotto (c.1450-99), the Venetian navigator and explorer. His claim turns on the fact that Columbus did not reach the American mainland until 1498, while he touched the North American shore a full year earlier. That he had set sail from England caused him to be remembered in the Anglophone world as John Cabot and shifted bragging rights from Venice to the ‘Sceptred Isle’. Then it turned out that, while Cabot found investors in Bristol and received a patent from Henry VII, his principal financial backer was an Italian banking house in London. The laurels shifted back to Italy.

Discoveries and doubts

In 1966 an English scholar, Alwyn Ruddock, discovered a letter of 1498 written to Columbus by an English merchant named John Day. In it, Day asserted that it was ‘considered certain’ that the North American mainland, which Cabot had visited the previous year, had been ‘found and discovered in the past’ by seamen from the port of Bristol (which happened to be Ruddock’s home town). Ruddock unearthed more papers suggesting that these pioneering Englishmen had reached America as early as 1470. Unfortunately Ruddock ordered all of these papers to be destroyed at her death in 2005. Just as it seemed that the prize was about to head north again, fresh doubts set in.

Amid this ping-pong match, Francesco Guidi-Bruscoli, the Italian historian who had discovered information on Cabot’s Italian backers, came across a yellowed parchment map with an intriguing notation suggesting that Cabot may have been dispatched to confirm a discovery made many years earlier. Written in Italian, it states that ‘Giovanni Chabotte’ (Cabot) from Venice had been commissioned to sail to the ‘new land’. That the reference to new land was preceded in Italian by the definite article, il, rather than the indefinite un suggested to Guidi-Bruscoli that Cabot’s sponsors already knew of the Americas, thanks to reports by an earlier explorer. Cabot was simply verifying what was already known.

Meanwhile scholars from Scandinavia have examined the Norse sagas for evidence that their forebears had sailed to North American shores before the English and Italians. The story of Vikings plowing the waves in their narrow-hulled boats to explore and settle Greenland is by now well known and confirmed by archaeological finds along Greenland’s south-western coast. At the beginning of the 20th century Professor Gustav Storm of the University of Christiania in Oslo produced evidence that Norsemen had made several trips to within sight of the Canadian coast, identifying and naming Markland (southern Labrador), Helluland (Baffin Island) and Vinland, which is thought to be Nova Scotia.

Norse sagas

Among these adventurers Leif Ericson (970-1020), the son of Eric the Red (c.950-1003), who had discovered Greenland, entered the history books for his sighting of Vinland in about 1000. True, one saga from 1387 states that a certain Bjarni, Son of Herjulf, had beaten Leif to Vinland, having been blown off course and sighted land there as early as 985-6. But no further support for the Bjarni claim has turned up.

Just what is meant, then, by this Norse ‘discovery’ of North America? Leif Ericson was a Christian missionary who had been sent to Greenland by King Olaf I of Norway (r.995-1000) with orders to bring the faith to settlements there. On the return voyage his boat was blown so far south that he was brought within view of Nova Scotia. The authors of the Norse sagas, amazed that he survived this adventure, dubbed him ‘Leif the Lucky’.

Except for Ericson, most of the other Norsemen who made contact with North America were traders by profession. Had their commercial interests fared better, they might have given the continent a second look, but they didn’t. Their one serious venture onto North American territory resulted in a fight with native Americans, after which they quickly fled to their boats. The southernmost confirmed evidence of Vikings in the New World was discovered in 1960 at L’Anse aux Meadows, on the northern tip of Newfoundland.

From the sod houses and primitive artefacts that archaeologists excavated at L’Anse aux Meadows and in Greenland these Norse traders emerge as hardy adventurers. As to their ‘explorations’, they were carried out in a thoroughly ad hoc way, usually the result of accident or unfavourable winds. At their most deliberate the Vikings strove each time to sail a little further down a coastline than their immediate predecessor. Either way, when they returned to Greenland, Iceland or Norway they told their tales to wide-eyed listeners huddled around log fires. There is no evidence that any of the Viking leaders who headed towards North America were literate.

It took another three generations before Adam of Bremen (c.1050-1081/5) in northern Germany, wrote the Gesta Hammaburgensis Ecclesiae Pontificum, a chronicle which included the stories he had heard concerning the adventures of Leif the Lucky. Adam and other chroniclers and authors of the sagas offered their reports in a stolid and matter-of-fact way, with no indication that they had any idea of the implications of these remarkable travels.

At around the same time that the Vikings were venturing south and westward from their bases in Greenland, a very different process of discovery was taking place in landlocked territories many months’ journey from the nearest open salt water. Beginning more than 3,000 years ago, traders from the great urban centres of what is now Uzbekistan, Turkmenistan and Afghanistan had sent goods across Eurasia, from Europe to India and China. They moved their cargo in long camel caravans, which carried the equivalent of a dozen or more modern freight containers. Gold and silver coins minted in their cities were honoured as currency as far afield as Sri Lanka and England. Vikings, among others, collected hordes of these beautifully crafted coins because they knew they would be accepted widely. Once back home the Central Asian traders not only told their tales around neatly built hearths in solid multi-storey houses but wrote down detailed information on the geography and climates of the lands they had visited. Local scholars collected and analysed these reports.

A curious mind

The greatest of these scholars was Abu Raihan al-Biruni. Born in 973 near the Aral Sea in what is now Uzbekistan, while still a youth Biruni mastered mathematics, astronomy, mineralogy, geography, cartography, geometry and trigonometry. He spoke Persian, Arabic and Khwarazmian, the language of the Sunni dynasty that ruled Greater Iran between the 12th and 13th centuries. Later on he also studied Sanskrit.

While still a young man Biruni had calculated the latitude and longitude of his home town and had begun to collect similar co-ordinates for other places. Using ancient Greek sources he compiled data on hundreds of locales in the Mediterranean world and then began adding calculations on other locations from all points of the compass. From ancient writers like Claudius Ptolemy (c.150 BC), from more recent sources and from his own field observations he knew that the earth is round. By the time he was 30 Biruni was employing the most advanced systems of the day to calculate its precise circumference. In a pioneering effort not matched until the Renaissance he constructed a globe 16ft high showing the Earth’s terrestrial features.

Biruni followed in the footsteps of several other scientists from Central Asia. Among them was Ahmad al-Farghani, from what is now Uzbekistan, who in the ninth century had calculated the width of one degree of longitude at the equator, from which he deduced the earth’s circumference. His calculation, though less precise than Biruni’s, marked a significant improvement on those made by the ancient Greeks and assured a wide readership for his book on the subject, A Compendium of the Science of the Stars (c.833). Five centuries later Columbus came across a Latin translation of Farghani’s treatise. Besides welcoming confirmation that the Earth is round, Columbus used Farghani’s data to argue before sceptical potential sponsors that it was small enough for him potentially to circumnavigate. However, Columbus wrongly assumed that Farghani had presented his measurements in Roman miles rather than Arab miles. This caused him to understate the actual circumference of the earth by 25 per cent. His misreading caused (or, if it was deliberate, enabled) Columbus to place Cipango, or Japan, near the Virgin Islands. This convenient error proved crucial in Columbus obtaining funding for what he estimated would be a relatively short voyage to China.

Biruni had also delved into mineralogy, specifically the relative density and weight of minerals of all types and how the separate minerals interact in nature. In the process of this research he discovered the concept of specific gravity.

Just how Biruni acquired his passion for precise measurement is a mystery. It certainly owed something to his education, which included study of the classical Greek scientist Pythagoras, who had proclaimed that ‘things are numbers’. Biruni’s constant urge to quantify whatever he observed, combined with his enquiring mind, was to plunge him down a path that led to epochal insights, which in most respects put Columbus, Cabot and the Vikings in the shade.

By 1017 Biruni had become an honoured scientist at Gurganch, the intellectual capital of his home region of Khwarazm. But in that year a fierce and religiously fanatical Muslim ruler from Ghazni in Afghanistan, crushed Khwarazm and destroyed its capital. Mahmud of Ghazni, as he was known, was a brutal man but, like many rulers in the region, tried to surround himself with poets and learned scholars. He ordered Biruni to come to Ghazni and bring the results of his research with him.

Biruni, with no way out, not only complied but seized upon the move as an opportunity to learn more about India, which Mahmud had conquered over the previous decade. But Mahmud was as difficult as he was ruthless and Biruni quickly realised that he had to distance himself from his court. He removed to Lahore, now in Pakistan, where he penned the world’s first book on comparative religion, focusing on Hinduism and Islam. Gathering his notes and no equipment other than a simple astrolabe, he then withdrew to a heavily fortified hilltop castle at Nandana, not far from what is now Islamabad.

There Biruni returned to the old problem of measuring the earth’s circumference. To this end he devised a new technique, which involved careful observation, spherical trigonometry and the application of the law of sines. Besides being far simpler than using two distant points on flat land, this method produced a measure of the earth’s circumference that was a mere 10.44 miles less than the definitive modern measurement.

After Mahmud’s death in 1030, Biruni hauled his field notes and papers back to Ghazni in Afghanistan, where Mahmud’s son, Masud I (r.1031-40), welcomed him and helped him to settle into a quiet life of research and writing. Biruni wrote up his lifetime’s research on specific gravity and then turned to writing a vast tome, known as the Codex Masudicus, in which he summarised everything known at the time about astronomy and allied disciplines.

It was in the Codex Masudicus that Biruni considered the possibility that the sun is stationary and that the earth revolves around it. He stopped short of fully embracing a heliocentric view, noting instead that the notion of a heliocentric universe is no less logical than its alternative and called on mathematicians and astronomers either to refute it or accept it. It is no wonder that historians of science judge the Codex Masudicus to be the greatest work on astronomy from the period between late antiquity and the modern era. In his codex Biruni also hypothesised about the existence of North and South America.

Biruni began by presenting the research on the earth’s circumference that he had carried out at Nandana. He then set about fixing all known geographical locations onto his new, more accurate map of the globe. His list of longitudes and latitudes had grown substantially since his earliest collection and now included more than 70 sites in India alone, as well as hundreds of other locations stretching across the Eurasian land mass.

When Biruni transposed these data onto his map of the earth he noticed at once that the entire breadth of Eurasia, from the westernmost tip of Africa to the easternmost shore of China, spanned only about two fifths of the globe. This left three fifths of the Earth’s surface unaccounted for.

A world ocean

The most obvious way to explain this gap of 15,000 miles was to invoke the explanation that all geographers from antiquity down to Biruni’s day had accepted: that the Eurasian land mass was surrounded by a ‘World Ocean’. But was three fifths of the Earth’s circumference really nothing but water? Biruni considered this possibility but rejected it on the grounds of both observation and logic. From his study of specific gravity he knew that most solid minerals were heavier than water. Would so watery a world not give rise to serious imbalances to which the planet would have had to adjust over time? And why, he asked, would the forces that had given rise to land on two fifths of the earth’s belt not also have had an effect on the other three fifths as well? Biruni concluded that somewhere in the vast expanses of ocean between Europe and Asia there must be one or more unknown land masses or continents.

Were these unknown continents empty wildernesses or ones inhabited by human beings? To address this question Biruni turned to his data on longitudes. He noted that human beings inhabit a broad north-south band stretching from Russia to southern India and the heart of Africa. If the unknown continent or continents were uninhabited, he reasoned, they would have to lie either north or south of this band.

To pursue this hypothesis Biruni went beyond his field observations and employed Aristotelian logic, a reasoning process built from propositions. Noting that the Eurasian land mass stretched roughly around the Earth’s belt, he hypothesised that it must have been the result of powerful processes that would surely have obtained elsewhere. Known evidence of the Earth gave him no grounds for believing that the unknown continents would be squashed into the northernmost and southernmost latitudes. He concluded that the unknown land masses between the Atlantic and Pacific Oceans would have to be inhabitable as, in fact, they were.

Biruni reached these momentous conclusions about the existence of the New World by 1037, basing them on research he had conducted over the preceding three decades.

Did Biruni discover America in the first third of the 11th century? In one sense, definitely not. He never laid eyes on the New World or the continents about which he wrote. By contrast the Norsemen had actually touched land in North America shortly before ad 1000; briefly, to be sure, and without really understanding what they had found. Leif Ericson was so uninterested in the forested shore of North America that he did not bother to return later, nor did any of those who heard oral reports of Ericson’s travels or read about them in later Norse documents. Still, if ‘discovery’ includes the unreflective processes of Norse seafaring, then the prize must go to the Vikings.

Yet Biruni is at least as deserving of the title of North America’s discoverer as any Norseman. Moreover, the intellectual process by which he reached his conclusions is no less stunning than the conclusions themselves. His tools were not the hit-or-miss methods of Venetian seamen or Norse sailors but an adroit combination of carefully controlled observation, meticulously assembled quantitative data and rigorous logic. Only after a further half-millennium did anyone else apply such rigorous analysis to global exploration.

Having assembled all known knowledge of the subject, studying the wisdom of ancient Greeks and Indians as well as medieval Arabs and fellow Central Asians, Biruni devised completely new methods and technologies to generate his voluminous and precise data and processed it with the latest tools of mathematics, trigonometry and spherical geometry as well as the austere methods of Aristotelian logic. He was careful to present his conclusions in the form of hypotheses, on the understanding that other researchers would want to test and refine his findings. This did not happen for another five centuries. In the end European explorers confirmed his hypotheses and vindicated his bold proposals.

Breaking free

This son of Central Asia was arguably the greatest explorer between the ancient world and the great age of European exploration. Two features of Biruni’s work warrant this conclusion. First, he achieved what he did through the systematic and rigorous application of reason and logic, unconstrained by religious or secular dogmas, folklore or anecdotes. He was a Muslim, but broke free of the culture-bound assumptions of Islam in a way that scientists in the Christian West struggled for several more centuries to achieve. He carried out his breathtaking intellectual explorations while living far from the sea in a landlocked region and without leaving his study except to carry out scientific measurements. While he was absolutely confident in his conclusions, his written presentation of them indicated the precise paths by which someone seeking to disprove him might proceed.

Who today can better the credo that this Central Asian polymath penned a thousand years ago?

… in an absolute sense, science is good in itself, apart from its [content of] knowledge; its lure is everlasting and unbroken … [The servant of science] should praise the assiduous [ones] whenever their efforts [arises from] delight [in science itself] rather than from [the hope of achieving] victory in argument.

Even today, Biruni’s modus operandi strikes one as astonishingly modern, a voice of calm and dispassionate scientific enquiry sounding forth from the depths of the irrational and superstitious medieval world.

Biruni accomplished all this while living and working in a region which many still regard as backward, a region immersed in superstition, fanaticism and violence. His birthplace in western Uzbekistan is close to the Aral Sea, where from the 1950s the Soviet Union created one of the most fearful ecological disasters of modern times. His achievements took place in a bleak zone on the northern border of Turkmenistan, far from the enormous gas fields that are today transforming that country into a Central Asian Kuwait. His research at Nandana, in what is now the West Punjab territory of Pakistan, put him within an hour of Jammu and Kashmir, the future scenes of a half century of armed struggle between Pakistan and India. As to Ghazni in Afghanistan, where he penned his renowned Codex Masudicus, simply to reach this town today is a dangerous task, requiring armoured vehicles and armed guards to traverse the heavily mined road from Kabul or Kandahar.

But one can do so nonetheless and can, amid the desolate remains of ancient Ghazni, ferret out the actual tomb of Biruni. Here in the very heart of Afghanistan lie the remains of the most modern explorer of the Middle Ages, a man who was open to the entire world and to all the knowledge it contains.

If and when Afghanistan gains a stable government and begins to develop, travellers and tourists will visit Ghazni, the scene of Biruni’s great work as a global explorer, and pay their respects at the tomb of one whose achievements match those of Columbus.

By S. Frederick Starr | Published in History Today Volume: 63 Issue: 12 2013

S. Frederick Starr is research professor at the Paul H. Nitze School of Advanced International Studies at Johns Hopkins University and a founding chairman of the Central Asia-Caucasus Institute.