Islam’s Greek Inheritance: Mathematics, Science, and Philosophy

May 2022

‘Pythagoras is the presiding genius of mathematical study in Islam. Greek and Indian elements are mingled in it, it is true, but everything is regarded from a neo-Pythagorean point of view.’ - TJ De Boer, The History of Philosophy in Islam, 1903

In the second Islamic century, by the time the Abbasid Caliphate had built their new capital in Baghdad, Muslim administrators and scholars were able to draw on an extraordinary range of knowledge from the vast territories that were now under their control. Classical, Romano-Greek, Chinese, Indian, Persian, and Egyptian learning of many kinds became available and were investigated, but the most important source of general and practical knowledge remained the extensive body of Greek works that the Muslims had first encountered as a result of their conquest of the Byzantine territories of Egypt and Syria in the first flush of their conquests.

The early Muslims, who, under the Umayyad Caliphate, had established Damascus as their administrative center, were as impressed by the level of Greek erudition as they were by the general level of civilized life in Egypt and Syria. This part of the world had been under Roman rule for seven centuries, was heir to Hellenistic civilization, and had been Christian since the fourth century CE. At the time Islam entered this region, in the late seventh century CE, Greek science and literature from the earlier Classical and Hellenistic eras was still being taught (albeit filtered through a Christian lens), as were the philosophies of Plato and Aristotle. Neoplatonism, with its roots in these philosophies, was an abiding influence in this milieu (Morewedge, 1992).

From their first encounters with this huge body of Classical knowledge, however, Muslims tended to be divided in their responses. Classicism, with its infidel, pagan associations, was regarded with great suspicion by those of a strictly religious disposition, but since the administration of a rapidly increasing Empire had now to be conducted in Arabic, there was a pressing need for the translation of huge amounts of written material, including official documents, from their original Greek. The Muslims had much to learn and Byzantine sources had much to teach, and although the original impetus for the translation of Greek material may have been for purely practical reasons, increasing familiarization with this wealth of information inevitably led to a broader interest in Greek thought. Translations during this early period tended to be unofficial, i.e., by private sponsorship, but since these sources clearly had so much to offer in many fields, this was to change. As the numbers and quality of translations from Greek originals accumulated their value became ever more apparent. Medical treatises were of particular interest at this stage, as were those dealing with Astrology and Alchemy, but as more and more subjects were translated, they became part of a general cultural influence that was being absorbed by Muslim society. The eventual outcome of this cultural osmosis was that Islam accepted late-Classical Greek attitudes to such an extent that, almost by default, they became an important part of its own tradition. In many ways, the templates for Islamic civil life were set here and permanently incorporated into its own, Islamic, ethos.

The so-called Golden Age of Baghdad, in the second great Islamic Caliphate, the Abbasids (in the Third Islamic century), was characterized by an extraordinary enthusiasm for the translation of not only Greek but Parthian and Indian knowledge. But even by the time the renowned House of Wisdom (Bayt al-Hikma) was set up in Baghdad (830 CE), such important figures as Plato, Aristotle, and Plotinus were as familiar to Islamic intellectuals as they had long been to those in the Byzantine world. This process was facilitated by the earlier Christian and Jewish adjustments to Classical thought, which, in a manner of speaking, had “sanitized” its pagan associations, effectively making it more acceptable to Islamic sensibilities.

The transference of the Court from Damascus to Baghdad had meant that the “Byzantinization” of the Caliphate had to a great extent been superseded by a “Persianization” of its religio-political ideas, attitudes, and manners (even though the rulers still tended to be Arab). But the general appetite for Greek texts was undiminished. The Bayt al-Hikma was originally founded as a center for translation but naturally developed into a library, and then to a university, where Greek and other works were made available to scholars. The establishment of this institution also meant that original manuscripts on a whole range of academic subjects were soon being actively sought from all available sources, including Byzantium, Persia, and India. As in Damascus, the first texts to be translated were those of subjects that were deemed to be of most immediate use to the Rulers, including Medical, Astrological, Agricultural, and other technological treatises, but as the translation movement gathered pace, particularly during the reign of Caliph Harun ar-Rashid, scholars turned their attention to scientific and philosophical works. By the time of the rule of his son Caliph al-Mamun in the first half of the ninth century, the translation movement had become highly fashionable, involving many different teams of translators and scribes, funded both by the Royal Court and by private, wealthy individuals.

The increasing familiarity with Greek ideas in Baghdad court circles engendered a genuine sense of admiration, particularly for texts those dealing with philosophical/scientific and mathematical subjects. The works of Euclid, Apollonius, and Archimedes in particular came to be treated with enormous respect. Euclid whose famous Elements established the basis of plane geometry, was translated into Arabic during Harun ar-Rashid’s reign (786–809 CE) by the mathematician al-Hajjaj ibn Matar (who later provided his son, the future Caliph Ma’mun, with an abbreviated but improved version).

During the ninth century CE, Baghdad, as the capital of the Caliphate, was the intellectual, religious, and commercial center of the Islamic world. This was a period of extraordinary scientific and medical innovation – developments that were often associated with philosophical speculation. Increased understanding of the principles of Classical mathematics and geometry led naturally to a sense of self-confidence among Islamic intellectuals, allowing them to advance on and, where necessary, correct the assertions of their illustrious predecessors. During Caliph al-Mamun’s rule (813–833 CE), there was a marked increase in the commissioning of new work in a range of areas – including mathematics, astronomy, geography, and medicine. These often went far beyond mere translation. A new class of Islamic scholarship came into being that was capable of making commentaries on Greek works and was increasingly involved in original research. In astronomy, for instance, the study of Ptolemy’s Almagest encouraged Al-Mamun to set up a program to verify the accuracy of existing star charts. This in turn led to the appointment of official astronomers and the building of observatories in Baghdad and Damascus – laying the foundations of Islam’s 700-year involvement with this science (the considerable achievements of which contributed much to modern astronomy). The translation movement itself more or less came to an end around the end of the tenth century CE, largely because everything that was available had already been translated but also because by this time Islamic science was well and truly established on its own account and had produced a great deal of original work.

One of the more remarkable accomplishments of the era of Baghdad’s “Golden Age” and one that gives an indication of the general spirit of scientific enquiry at this time were the attempts to make an accurate measurement of the circumference of the Earth, a project in which Al-Mamun himself took a personal interest. This first attempt involved an accurate measurement of a stretch of flat desert in Sinjar, northwestern Iraq, and the comparison of the elevation of the Pole Star at the beginning and end of the process, then a calculation of the curvature of the Earth from the angular difference. The result, 8000 farsakhs (24,000 miles), which was checked by a second expedition, was remarkably accurate for its time.

Caliph al-Mamun personally employed the famous mathematician and astronomer al-Khwarizmi who, among many other achievements, was responsible for the introduction of Indian numerals into Arabic mathematics. Al-Khwarizmi also developed the procedure we now know as Algebra (al-Jebr) and gave his name to the term “algorithm.” There was a heady, pro-science atmosphere in the Baghdad court at this time, but in this early-Islamic setting, it was inevitable that the problem of reconciling Reason with Faith should arise. The Caliph’s response to mounting religious criticism of his proto-rationalistic views was to promote the theology known as Mu’tazilism, which argued that Allah’s moral obligations are accessible to rational thought and that, because knowledge derives from reason, the latter should be the “final arbiter.” The Mu’tazilites disliked conventional anthropomorphic interpretations of the Qur’ān and went so far as to declare that the Holy Book could not properly be considered as the word of Allah, since He could have no separable parts. In this view, the Qur’ān was therefore created, not eternal, as popular religious belief would have it.

This was heady stuff and an interpretation of basic Islamic precepts that did not go down at all well among the religiously orthodox, who bitterly opposed every aspect of these rationalistic ideas. In the event, this conflict brought about an ideological crisis that led the Caliph, al-Mamun, to attempt to force the issue by making the acceptance of Mu’tazilism a condition of official service and, in the face of continuing opposition, instituted an Inquisition (mihnah) against those who refused to accept his ruling. This, in turn, prompted a strong religious and popular reaction against these moves, so that Caliph’s attempt at imposing a degree of separation between rational practice and religious observance ultimately failed. With hindsight, this proved to be a fork in the road for Islam, where eventually Faith was to take precedence over Reason – as a result of which the influence of Classical, Hellenistic attitudes decreased. Scientific ideas and sceptical, rational thought were to continue to play an important role in the Islamic world over the following centuries, and many important discoveries were made but, objectively speaking, Islamic science peaked around 1000 CE and went into a long, slow decline. Unfortunately, the tendencies toward religious conservatism and dogma within the Islamic world after this time increasingly tended to create conditions that were less conducive to the pursuit of scientific knowledge.

A key moment in this process occurred in the eleventh century CE when the influential theologian Al-Ghazali, in a work entitled The Incoherence of the Philosophers (Tahafut al-Falasifa), attacked the entire Greek philosophical tradition (in particular the Emanationist principles of Neo-Platonism), denouncing them as a form of heresy. This declaration marked an important shift in Islamic epistemology. However, by this time, Neoplatonic attitudes had been thoroughly assimilated into mainstream Islamic thought, and ironically Al-Ghazali himself used Classical dialectical methods in his refutation of this and other Classical philosophies. However, Neo-Platonism continued to influence Islamic culture in many subtle ways - indeed the otherworldly, geometrical, preoccupations of Islamic art can be seen as part of this enduring legacy. The complex ideas of this religious philosophy are unlikely to have been of interest to most artist/craftsmen, but they (along with many others in Islamic society) seem to have absorbed many of its broad notions by way of the cultural osmosis referred to above.

Al-Ghazali (1058–1111 CE) was a towering figure in Islamic cultural history and is still counted as one of its greatest religious thinkers. He is important because by his time, the question of ultimate authority in matters of law and legislation (which had its roots in the Mu’tazilism controversy mentioned above) had become part of a cultural crisis. Islamic society had developed in a variety of somewhat irreconcilable directions – among which was the continuing challenge of the Hellenistic rational/philosophic tradition. Al-Ghazali experienced this epistemological fracturing at a most personal level, in the form of a crisis of faith and conscience that led to a complete mental and physical breakdown. His recovery from this traumatic experience came in the form of a conversion from his previous extreme philosophical skepticism to a more mystical acceptance of the role of prophetic revelation. His Revival of the Religious Sciences (Ihya ulum l-din), amounting as it did to a thorough refocusing of Islamic verities, was enormously influential. From this and other works, he came to be regarded as the “Restorer of the Faith.” His achievement is reflected in the fact that his ideas managed to achieve widespread acceptance. To the Sufi’s, he remained a mystic; more orthodox theologians regarded him as an important religious teacher; and for the legalists, he continued to be admired as an eminent jurist.

In a much later, somewhat ironical, development, Al-Ghazali (who was credited with producing some 70 books) came indirectly to influence European rational thought in its slow emergence from the Dark Ages – particularly through the philosophical works of Thomas Aquinas and Pascal.