Islamic and Jewish Philosophy

Islamic and Jewish philosophy is the tradition of reasoned inquiry that grew up in the lands of Islam from the eighth century onward, written mostly in Arabic and later in Persian, by Muslims, Jews and Christians who shared the same Greek inheritance. It stretched from Central Asia to Spain and from Baghdad's ninth-century translators to the Persian philosophers of the seventeenth century. Its thinkers argued about whether the world had a beginning, whether God knows individual things, how the soul relates to the body, what causes really are, and how a revealed law relates to the conclusions of reason.

The tradition matters twice over. In its own right it produced some of the most original metaphysics ever written. And it was the channel through which Aristotle and much of Greek science reached medieval Europe, so that the story told under medieval Christian philosophy cannot be understood without it. Its roots lie in the late Greek schools described under Hellenistic and Roman philosophy.

After the Arab conquests of the seventh century, which followed the death of Muhammad in 632, the new empire ruled cities such as Alexandria, Antioch and Edessa where Greek learning had long been studied. Syriac-speaking Christians had already translated parts of Aristotle's logic into their own language, and the court of the Sasanian Empire had sponsored translations into Middle Persian. Under the Umayyad Caliphate, ruled from Damascus, a few Greek texts were rendered into Arabic, but systematic work began only after 750, when the Abbasid Caliphate took power and moved the capital east.

In 762 the caliph al-Mansur founded Baghdad, and over the next two centuries caliphs, courtiers and wealthy families paid for Greek works to be translated into Arabic. Harun al-Rashid and especially his son al-Ma'mun (r. 813–833) were notable patrons. The motives were mixed: practical demand for medicine, astronomy and mathematics, the prestige of presenting the Abbasids as heirs of ancient wisdom, and a need for logic in religious debate. The court library, the House of Wisdom, is often described as a translation academy, though scholars now think it was chiefly a library and that the translators worked for many different patrons. Scientists such as al-Khwarizmi worked in this setting.

The most productive translator was Hunayn ibn Ishaq (809–873), a Nestorian Christian physician who, with his son Ishaq and his nephew Hubaysh, translated most of Galen and much of Aristotle, often first into Syriac and then into Arabic. By the tenth century Arabic readers had nearly all of Aristotle, works by Galen, Euclid and Ptolemy, and Neoplatonic texts, some of them misattributed. One, the so-called Theology of Aristotle, was in fact a paraphrase of parts of Plotinus, and it led Arabic philosophers to read Aristotle through a Neoplatonic lens, with the world emanating in stages from a single divine source. This flowering of science and scholarship is often called the Islamic Golden Age.

Alongside the translators, Muslim theologians developed kalam, literally "speech" or discussion, a method of rational argument in defence of religious doctrine. The first major school, the Mu'tazila, emerged in Basra in the eighth century. Its members insisted on God's absolute unity, so that God's attributes such as knowledge or power could not be separate eternal realities beside him, and on God's justice, which they took to require that humans have genuine free will, since punishing people for acts they could not avoid would be unjust. They held that reason can know right and wrong independently of revelation, and that the Quran was created in time rather than eternal.

Al-Ma'mun adopted the doctrine of the created Quran and in 833 began the mihna, a test in which judges and scholars had to affirm it. The traditionalist scholar Ahmad ibn Hanbal refused and was imprisoned and flogged. The policy was abandoned around 848 under al-Mutawakkil, and Mu'tazilite influence at court declined, though the school survived for centuries, especially among Shi'is.

Its most important successor was founded by al-Ash'ari (c. 874–936), who had trained as a Mu'tazilite before breaking with his teachers. The Ash'aris used rational argument to defend more traditional positions: the Quran is God's eternal speech, God's attributes are real, and good and evil are what God commands and forbids, not standards that reason can impose on him. Many later Ash'aris held that the world consists of atoms and momentary accidents that God re-creates at every instant, so that there is no real causal power in created things. Fire does not burn cotton; God creates the burning when the two meet. This view, called occasionalism, protected divine omnipotence. A parallel school, founded by al-Maturidi in Samarkand, allowed more room for human choice and became dominant among Hanafi Muslims in Central Asia and later in the Ottoman lands.

The philosophers proper, the falasifa (from the Greek philosophia), worked in the tradition of Aristotle and the Neoplatonists. The first was al-Kindi (c. 801–c. 870), an Arab aristocrat at the Abbasid court who supervised a circle of translators and wrote on everything from optics to music. He argued that truth should be welcomed from any source, even foreign peoples, and that philosophy and revelation agree. Unlike most later philosophers he held, with the theologians, that the world was created from nothing and has a finite past, and he offered arguments that an actually infinite past is impossible.

Al-Farabi (c. 870–950), probably born in Central Asia, worked in Baghdad and later in Aleppo and Damascus. He was so admired as a logician and commentator that he became known as the Second Teacher, after Aristotle. He presented a cosmos in which a chain of intellects emanates from the First Cause, the lowest of them, the Active Intellect, illuminating human minds. In The Virtuous City he applied Plato's Republic to an Islamic setting: the ideal ruler is a philosopher-prophet who grasps truth intellectually and conveys it to ordinary people through symbols and laws. Religion, on this account, is philosophy expressed in images for the many, which placed philosophers in a delicate position with the guardians of the faith.

Avicenna, Ibn Sina (980–1037), was born near Bukhara in the Samanid Empire, in modern Uzbekistan. A prodigy, he claimed to have mastered most sciences by eighteen. He spent his career as physician and vizier to rival princes in Iran, including the Buyid rulers of Hamadan and the Kakuyid court at Isfahan. His Canon of Medicine was a standard textbook in both the Islamic world and Europe for centuries, and his Book of Healing is a vast encyclopaedia of logic, natural science, mathematics and metaphysics.

Avicenna did not simply comment on Aristotle; he rebuilt the system. He distinguished sharply between a thing's essence, what it is, and its existence, that it is. Considering the essence of a horse tells you nothing about whether any horse exists, so every ordinary thing is merely possible in itself and needs a cause to exist. A chain of such causes must end in a being whose existence is necessary in itself, the Necessary Existent, which he identified with God. In his famous thought experiment of the "floating man", a person created suspended in the air, with no sensations and no contact with his own body, would still be aware that he exists, showing, Avicenna argued, that the self is distinct from the body. He held that the world emanates eternally from God and that God knows particular things only "in a universal way", positions that would bring him into conflict with the theologians. Avicenna's system became the starting point for nearly all later philosophy and theology in the eastern Islamic world.

Al-Ghazali (1058–1111), born in Tus in northeastern Iran, was appointed in 1091 to teach at the Nizamiyya college in Baghdad, founded by the vizier of the Seljuk Empire. He studied the philosophers thoroughly, summarising their views before attacking them. In The Incoherence of the Philosophers (c. 1095) he examined twenty of their doctrines and argued that they had failed to prove them by their own demonstrative standards. Three, he said, amounted to unbelief: that the world is eternal, that God does not know particulars, and that there is no bodily resurrection.

His most famous argument concerns causation. We see that fire is always followed by burning, but, al-Ghazali argued, observation shows only that one follows the other, not that the fire produces the burning by necessity. God could create one without the other, as the stories of miracles require. The argument is often compared to David Hume's analysis of causation more than six centuries later. Soon after, al-Ghazali underwent a spiritual crisis, left his post in 1095 and turned to Sufism, describing the search in his autobiography Deliverance from Error. Contrary to an old view, he did not end philosophy in Islam. He kept and promoted Aristotelian logic, and after him theologians absorbed much of Avicenna's metaphysics into kalam, a synthesis carried forward by Fakhr al-Din al-Razi (1149–1209).

In the Iberian peninsula, Muslim al-Andalus had been ruled since 756 by a branch of the Umayyad dynasty, and its capital Córdoba was among the largest and most learned cities in Europe in the tenth century. After the Umayyad caliphate there collapsed in 1031, the region broke into small kingdoms and was later ruled from North Africa by the Almoravid dynasty and then the Almohad Caliphate. Philosophy came late here but produced a distinctive school. Ibn Bajja (d. 1138), known in Latin as Avempace, wrote on the solitary life of the philosopher in an imperfect society. Ibn Tufayl (d. 1185), court physician in Marrakesh, wrote Hayy ibn Yaqzan, a philosophical tale of a boy raised alone on an island who reasons his way, unaided, to knowledge of God and then finds that it matches the religion of a neighbouring island.

Ibn Tufayl introduced to the Almohad caliph Abu Ya'qub Yusuf a young judge from Córdoba, Averroes, Ibn Rushd (1126–1198), who was asked to explain Aristotle's difficult works. Averroes wrote short, middle and long commentaries on almost the whole corpus, trying to recover the real Aristotle from Neoplatonic accretions, including Avicenna's. In The Incoherence of the Incoherence he answered al-Ghazali point by point, and in the Decisive Treatise he argued, as a legal scholar, that the Quran actually commands those capable of it to study philosophy. Scripture speaks to everyone, he said, using rhetoric for the many, dialectic for the theologians and demonstration for philosophers, and where a demonstrated truth seems to contradict a verse, the verse should be interpreted. He also argued that there is only one material intellect for all humankind, a thesis that would cause uproar in Paris. Briefly disgraced around 1195, possibly for political reasons, he died in Marrakesh in 1198. His influence in the Islamic world was limited, but in Latin and Hebrew translation he became one of the most read authors in Europe.

Other Andalusians took different paths. Ibn Arabi (1165–1240), born in Murcia and buried in Damascus, became the most influential theorist of Sufi mysticism, teaching a vision of all existence as the self-manifestation of God. The last Muslim state in the peninsula, the Emirate of Granada, fell in 1492, completing the Reconquista.

Jews in the Islamic world spoke and wrote Arabic, and Jewish philosophy, part of the wider history of Judaism, developed in direct dialogue with kalam and falsafa. Saadia Gaon (882–942), born in the Fayyum in Egypt and later head of the academy of Sura near Baghdad, wrote The Book of Beliefs and Opinions, the first systematic Jewish philosophy of the Middle Ages. Close to the Mu'tazila, he held that reason and revelation lead to the same truths, argued for creation from nothing, and defended human free will, while rejecting their atomism.

In al-Andalus, the poet Solomon ibn Gabirol (c. 1021–c. 1058) wrote The Fountain of Life, a Neoplatonic work that circulated in Latin under the name Avicebron; its Jewish authorship was forgotten until the nineteenth century. Judah Halevi (c. 1075–1141), another great poet, attacked the philosophers in the Kuzari, a dialogue in which the king of the Khazars questions a philosopher, a Christian, a Muslim and a rabbi before choosing Judaism. Halevi argued that the historical experience of revelation at Sinai, witnessed by a whole people, gives a certainty that abstract argument cannot.

The greatest Jewish philosopher of the age was Maimonides, Moses ben Maimon (1138–1204). Born in Córdoba, he left with his family when the Almohads imposed conversion on non-Muslims, lived for a time in Fez and settled by 1166 in Fustat, the old city of Cairo, where he became leader of the Jewish community and a physician at the court of Saladin's family. Besides a monumental code of Jewish law, he wrote The Guide of the Perplexed (completed 1190) for readers torn between Scripture and Aristotle. He taught that nothing positive can be said about God's essence; the more one denies of God, the closer one comes to the truth. He argued that neither the eternity of the world nor its creation can be demonstrated, and that creation is the more reasonable belief. The Guide was banned and even burned by some opponents in the Maimonidean controversies of the thirteenth century, but it shaped Jewish thought permanently. Later Jewish philosophers in Provence and Spain, such as Gersonides (1288–1344) and Hasdai Crescas (c. 1340–1410), continued to debate Aristotle, with Crescas mounting a pioneering critique of Aristotelian physics.

Ibn Khaldun (1332–1406), born in Tunis under the Hafsid dynasty to a family of Andalusian origin, served several North African and Andalusian courts before withdrawing to write. The Muqaddimah (Introduction), drafted in 1377 as the preface to a universal history, set out what he called a new science of human society. He argued that historians must test reports against an understanding of how societies actually work. Dynasties rise, he proposed, through the asabiyya, or group solidarity, of hardy nomadic or rural peoples; once settled in cities, they grow wealthy and soft, lose that cohesion, and are replaced by new groups, in cycles of roughly three or four generations. He also wrote perceptively on economics, labour and taxation. He spent his last years as a judge in Cairo under the Mamluk Sultanate, and in 1401 met Tamerlane outside besieged Damascus. Largely neglected for centuries, he was rediscovered by Ottoman and then European scholars and is now regarded as a forerunner of sociology.

In the east, philosophy did not decline after the twelfth century, as older histories claimed. Shihab al-Din Suhrawardi (c. 1154–1191), born in northwestern Iran, founded the Illuminationist school. In The Philosophy of Illumination (1186) he criticised Avicenna's Aristotelianism and built a metaphysics of light: reality is a hierarchy of lights of varying intensity, descending from the Light of Lights, which is God, and true knowledge is not a mental picture of an object but direct awareness of it, knowledge by presence, of the kind we have of ourselves. He drew deliberately on Plato, ancient Persian wisdom and Sufi experience. He was executed in Aleppo around 1191, on charges of heresy, under the Ayyubid prince al-Zahir, a son of Saladin.

After the Mongol Empire destroyed Baghdad in the siege of 1258, patronage moved elsewhere. Nasir al-Din al-Tusi (1201–1274), adviser to the founder of the Ilkhanate, defended Avicenna's philosophy against its critics and ran the observatory at Maragha. Commentary and teaching continued in the schools of Shiraz, of the Timurid Empire and of the Ottoman Empire.

The last great flowering came under the Safavid Empire in Iran, where Shi'ism became the state religion and Isfahan became the capital in 1598. Teachers such as Mir Damad and Shaykh Baha'i formed what modern scholars call the school of Isfahan. Their most famous student, Mulla Sadra (c. 1571–1635), from Shiraz, synthesised Avicenna, Suhrawardi, Ibn Arabi and kalam. Reversing Suhrawardi, he held that existence, not essence, is what is fundamentally real, and that existence comes in degrees of intensity. He also argued for substantial motion: change happens not only to a thing's qualities but to its very substance, so the whole world is in constant becoming. His "transcendent philosophy" still dominates teaching in Iran's religious seminaries.

From the twelfth century, scholars in Toledo, conquered by the Christian kingdom of Castile in 1085, and in Sicily around Palermo, translated Arabic works into Latin, often with Jewish intermediaries who rendered the Arabic orally into a Romance language. Gerard of Cremona translated dozens of scientific and philosophical texts, Dominicus Gundissalinus and the Jewish scholar Abraham ibn Daud translated Avicenna, and Michael Scot translated Averroes in the 1220s. In Provence, the Ibn Tibbon family translated Maimonides, Averroes and others into Hebrew, creating a Hebrew philosophical library.

The results reshaped European thought. Avicenna's distinction between essence and existence and al-Farabi's classification of the sciences entered the Latin curriculum. Averroes became simply the Commentator, and Latin "Averroists" at Paris, with their thesis of a single intellect for humanity, provoked the condemnations of 1277. Thomas Aquinas cited Avicenna, Averroes and Maimonides constantly, often with respect, and Averroism remained a live force at Padua into the Renaissance. Ibn Tufayl's tale, translated into Latin in 1671, was read by early modern thinkers interested in natural reason. The traffic, then, ran in one great loop: Greek philosophy passed from Athens and Alexandria into Syriac and Arabic, was developed for four centuries in Baghdad, Bukhara, Córdoba and Cairo, and returned to Europe, transformed, in Latin. For how this tradition fits into the wider story, see the history of philosophy.