Al-Ghazâlî (c.1056–1111) was one of the most prominent and influential philosophers, theologians, jurists, and mystics of Sunni Islam. He was active at a time when Sunni theology had just passed through its consolidation and entered a period of intense challenges from Shiite Ismâ’îlite theology and the Arabic tradition of Aristotelian philosophy (falsafa). Al-Ghazâlî understood the importance of falsafa and developed a complex response that rejected and condemned some of its teachings, while it also allowed him to accept and apply others. Al-Ghazâlî’s critique of twenty positions of falsafa in his Incoherence of the Philosophers (Tahâfut al-falâsifa) is a significant landmark in the history of philosophy as it advances the nominalist critique of Aristotelian science developed later in 14th century Europe. On the Arabic and Muslim side al-Ghazâlî’s acceptance of demonstration (apodeixis) led to a much more refined and precise discourse on epistemology and a flowering of Aristotelian logics and metaphysics. With al-Ghazâlî begins the successful introduction of Aristotelianism or rather Avicennism into Muslim theology. After a period of appropriation of the Greek sciences in the translation movement from Greek into Arabic and the writings of the falâsifa up to Avicenna (Ibn Sînâ, c.980–1037), philosophy and the Greek sciences were “naturalized” into the discourse of kalâm and Muslim theology (Sabra 1987). Al-Ghazâlî’s approach to resolving apparent contradictions between reason and revelation was accepted by almost all later Muslim theologians and had, via the works of Averroes (Ibn Rushd, 1126–98) and Jewish authors, a significant influence on Latin medieval thinking.

Life

Later Muslim medieval historians say that Abû Hâmid Muhammad ibn Muhammad al-Ghazâlî was born in 1058 or 1059 in Tabarân-Tûs (15 miles north of modern Meshed, NE Iran), yet notes about his age in his letters and his autobiography indicate that he was born in 1055 or 1056 (Griffel 2009, 23–25). Al-Ghazâlî received his early education in his hometown of Tus together with his brother Ahmad (c.1060–1123 or 1126) who became a famous preacher and Sufi scholar. Muhammad went on to study with the influential Ash’arite theologian al-Juwaynî (1028–85) at the Nizâmiyya Madrasa in nearby Nishapur. This brought him in close contact with the court of the Grand-Seljuq Sultan Malikshâh (reg. 1071–92) and his grand-vizier Nizâm al-Mulk (1018–92). In 1091 Nizâm al-Mulk appointed al-Ghazâlî to the prestigious Nizâmiyya Madrasa in Baghdad. In addition to being a confidante of the Seljuq Sultan and his court in Isfahan, he now became closely connected to the caliphal court in Baghdad. He was undoubtedly the most influential intellectual of his time, when in 1095 he suddenly gave up his posts in Baghdad and left the city. Under the influence of Sufi literature al-Ghazâlî had begun to change his lifestyle two years before his departure (Griffel 2009, 67). He realized that the high ethical standards of a virtuous religious life are not compatible with being in the service of sultans, viziers, and caliphs. Benefiting from the riches of the military and political elite implies complicity in their corrupt and oppressive rule and will jeopardize one’s prospect of redemption in the afterlife. When al-Ghazâlî left Baghdad in 1095 he went to Damascus and Jerusalem and vowed at the tomb of Abraham in Hebron never again to serve the political authorities or teach at state-sponsored schools. He continued to teach, however, at small schools (singl. zâwiya) that were financed by private donations. After performing the pilgrimage in 1096, al-Ghazâlî returned via Damascus and Baghdad to his hometown Tûs, where he founded a small private school and a Sufi convent (khânqâh). In 1106, at the beginning of the 6th century in the Muslim calendar, al-Ghazâlî broke his vow and returned to teaching at the state-sponsored Nizâmiyya Madrasa in Nishapur, where he himself had been a student. To his followers he justified this step with the great amount of theological confusion among the general public and pressure from authorities at the Seljuq court (al-Ghazâlî 1959a, 45–50 = 2000b, 87–93). Al-Ghazâlî regarded himself as one of the renewers (singl. muhyî) of religion, who, according to a hadîth, will come every new century. In Nishapur, al-Ghazâlî’s teaching activity at the Nizâmiyya madrasa led to a controversy that was triggered by opposition to his teachings, particularly those in his most widely read work, The Revival of the Religious Sciences, and by accusations that these show a distinct influence from falsafa. Al-Ghazâlî was summoned to defend himself in front of the Seljuq governor Sanjar (d. 1157). The latter, however, acquitted him from all charges and supported his teaching activity in Nishapur (Garden 2014: 143–168). On this occasion, al-Ghazâlî again asked to be released from his obligations at the Nizâmiyya madrasa, a request that was denied. All this time, he continued to teach at his zâwiya in Tûs where he died in December 1111 (Griffel 2009, 20–59).

The Place of falsafa in Islam

In his attempt to define the boundaries of Islam al-Ghazâlî singles out a limited number of teachings that in his opinion overstep the borders. In a separate book, The Decisive Criterion for Distinguishing Islam from Clandestine Unbelief (Faysal al-tafriqa bayna l-Islâm wa-l-zandaqa) he clarifies that only teachings that violate certain “fundamental doctrines” (usûl al-‘aqâ’id) should be deemed unbelief and apostasy. These doctrines are limited to three: monotheism, Muhammad’s prophecy, and the Qur’anic descriptions of life after death (al-Ghazâlî 1961, 195 = 2002, 112). He stresses that all other teachings, including those that are erroneous or even regarded as “religious innovations” (singl. bid’a), should be tolerated. Again other teachings may be correct, al-Ghazâlî adds, and despite their philosophical background, for instance, should be accepted by the Muslim community. Each teaching must be judged by itself, and if found sound and in accordance with revelation, should be adopted (al-Ghazâlî 1959a, 25–27 = 2000b, 67–70). This attitude leads to a widespread application of Aristotelian teachings in al-Ghazâlî’s works on Muslim theology and ethics.

Al-Ghazâlî’s refutations of the falâsifa and the Ismâ’îlites have a distinctly political component. In both cases he fears that the followers of these movements as well as people with only a cursory understanding of them might believe that they can disregard the religious law (sharî’a). In the case of the Ismâ’îlites there was an additional theological motive. In their religious propaganda the Ismâ’îlites openly challenged the authority of Sunni theology, claiming its religious speculation and its interpretation of scripture is arbitrary. The Sunni theologians submit God’s word to judgments that appear to be reasonable, the Ismâ’îlites said, yet they are purely capricious, a fact evident from the many disputes among Sunni theologians. No rational argument is more convincing than any of its opposing rational arguments, the Ismâ’îlites claimed, since all rational proofs are mutually equivalent (takâfu’ al-adilla). Only the divinely guided word of the Shiite Imam conveys certainty (al-Ghazâlî 1964b, 76, 80 = 2000b, 189, 191). In response to this criticism al-Ghazâlî introduces the Aristotelian notion of demonstration (burhân). Sunni theologians argue among each other, he says, because they are largely unfamiliar with the technique of demonstration. For al-Ghazâlî, reason (‘aql) is executed most purely and precisely by formulating arguments that are demonstrative and reach a level where their conclusions are beyond doubt. Al-Ghazâlî wrote in one of his letters to a student that later circulated as an independent epistle: “A [valid] rational demonstration is never wrong” (Griffel 2015: 110–112). This also implies that the results of true demonstrations cannot conflict with revelation since neither reason nor revelation can be considered false. If demonstration proves something that violates the literal meaning of revelation, the scholar must apply interpretation (ta’wîl) to the outward text and read it as a symbol of a deeper truth. There are, for instance, valid demonstrative arguments proving that God cannot have a “hand” or sit on a “throne.” These prompt the Muslim scholar to interpret the Qur’anic passages where these words appear as symbols (al-Ghazâlî 1961, 175–89 = 2002, 96–103). The interpretation of passages in revelation, however, whose outward meaning is not disproved by a valid demonstration, is not allowed (Griffel 2000, 332–35; 2009, 111–16).

Al-Ghazâlî’s rule for reconciling apparent conflicts between reason and the literal meaning of revelation was widely accepted by almost all later Muslim theologians, particularly those with rationalist tendencies. Ibn Taymiyya (1263–1328), however, criticized al-Ghazâlî’s rule from an scriptualist angle. Ibn Taymiyya (1980, 1:86–87) rejected al-Ghazâlî’s implication that in cases of conflict between reason and the revealed text, priority should be given to the former over the latter. He also remarked that al-Ghazâlî’s own arguments denying the possibility that God sits on a “throne” (Qur’an 2.255), for instance, fail to be demonstrative. Ibn Taymiyya flatly denied the possibility of a conflict between reason and revelation and maintained that the perception of such a disagreement results from subjecting revelation to premises that revelation itself does not accept (Heer 1993, 188–92).

On the falâsifa’s side Averroes accepted al-Ghazâlî’s rule for reconciling conflicts between reason and the outward meaning of revelation but he did not agree with his findings on what can and cannot be demonstrated (Griffel 2000, 437–61). Averroes composed a refutation of al-Ghazâlî’s Incoherence, which he called The Incoherence of the [Book of the] Incoherence (Tahâfut al-tahâfut). This work was translated twice into Latin in 1328 and 1526, the later one on the basis of an earlier Hebrew translati