The Persian theologian and mystic whose Incoherence of the Philosophers redrew the boundary between philosophy and revelation in Sunni Islam, and whose autobiographical Deliverance from Error remains one of the most read accounts of religious crisis.
al-ghazali
Persian Ashʿarite theologian, jurist, and Sufi (1058–1111) whose Tahāfut al-Falāsifa challenged the rationalist program of Avicenna and whose Iḥyāʾ ʿUlūm al-Dīn became the most influential work of Sunni piety, reshaping the relationship of philosophy, theology, and mystical practice in Islam.
Life
Abū Ḥāmid Muḥammad ibn Muḥammad al-Ghazālī was born in 1058 in Ṭūs, in the Persian province of Khurāsān. His family was modest — his father, a wool merchant (Ghazāl in Persian means wool-spinner, though the derivation of the family name is disputed by Frank Griffel and others) — but provided for his and his brother Aḥmad's education before his early death. Al-Ghazali studied jurisprudence first in Ṭūs, then under the Ashʿarite theologian al-Juwaynī at the Niẓāmiyya madrasa of Nīshāpūr, the great training ground for Sunni religious scholars under the Seljuq vizier Niẓām al-Mulk.
At thirty-three al-Ghazali was appointed to the chair of Shāfiʿī law at the Niẓāmiyya of Baghdad, the most prestigious position in Sunni higher learning. He held it for four years, lecturing to hundreds of students and serving as advisor to the Seljuq court. The works of this period included refutations of Ismāʿīlī Shīʿism (commissioned by the caliph), the systematic legal work al-Mustaṣfā, and — most consequentially — the Tahāfut al-Falāsifa, written between 1093 and 1095 after a deep study of Aristotelian philosophy from the works of Avicenna and al-Fārābī.
In July 1095 al-Ghazali experienced a crisis he later described in his autobiography, al-Munqidh min al-Ḍalāl (Deliverance from Error, c. 1108). He lost the capacity to speak — a physical collapse that physicians attributed to spiritual distress — and concluded that his career as a Sunni jurist had been driven by ambition and worldly esteem rather than by sincere pursuit of God. He left Baghdad in November 1095, ostensibly on pilgrimage, distributed his wealth, and spent the next eleven years in retreat — primarily in Damascus and Jerusalem, with stays in Mecca and Medina — pursuing the Sufi path under the discipline of poverty, solitude, and contemplative practice.
During this period he composed his masterpiece, the Iḥyāʾ ʿUlūm al-Dīn (The Revival of the Religious Sciences), a forty-book systematic integration of Sunni jurisprudence, theology, and Sufi spirituality. Pressured by the vizier Fakhr al-Mulk, he returned briefly to teach at the Niẓāmiyya of Nīshāpūr around 1106, then withdrew again to Ṭūs, where he died on 18 December 1111.
The Tahāfut al-Falāsifa
The Incoherence of the Philosophers is structured as a polemic against twenty doctrines drawn from Avicenna and al-Fārābī, but the polemic is internal — al-Ghazali demonstrates, on the philosophers' own logical principles, that their proofs fail. Michael Marmura's edition and translation (The Incoherence of the Philosophers, Brigham Young University Press, 1997, 2nd ed. 2000) is the standard reference.
Three theses al-Ghazali identifies as not merely false but as constituting unbelief (kufr), the holder of which is to be regarded as outside Islam:
- The eternity of the world. Al-Ghazali argues that the philosophers' rejection of temporal creation, derived from Aristotle's Physics via Avicenna, contradicts the Qurʾānic account of creation ex nihilo.
- God's knowledge only of universals. Avicenna had argued that God knows particulars only "in a universal way" — through their kinds — to avoid attributing change to God. Al-Ghazali argues this denies the Qurʾānic doctrine of divine omniscience and providence.
- The denial of bodily resurrection. The philosophers, holding the soul's immateriality and immortality, denied that resurrection involved the body. Al-Ghazali argues this contradicts explicit revelation.
The seventeenth discussion of the Tahāfut presents al-Ghazali's most philosophically influential argument: a critique of necessary causation. The connection between what we call cause and effect — fire and burning, for instance — is, al-Ghazali argues, not necessary but customary. We see fire and cotton come into contact and burning follow; we have no demonstration that the fire produces the burning rather than God producing it in the customary order. This argument, which Lenn Goodman, Frank Griffel, and Taneli Kukkonen have analyzed in detail, anticipates Hume's critique of induction by seven centuries.
The Tahāfut did not destroy Islamic philosophy — Avicennan philosophy continued and deepened in the Shīʿī Iranian tradition under Suhrawardī, Mullā Ṣadrā, and others — but it changed the institutional position of philosophy in Sunni learning. Where philosophy had been taught alongside theology at madrasas, after al-Ghazali it was increasingly absorbed into Ashʿarite theology as a tool, rather than a competitor.
The Iḥyāʾ ʿUlūm al-Dīn
The Iḥyāʾ is divided into four quarters of ten books each: acts of worship, customs, things leading to perdition (vices), and things leading to salvation (virtues). Each book covers its topic from the perspective of the exoteric jurist, then the esoteric Sufi, integrating the two without subordinating either.
The work's significance lies in its rehabilitation of Sufism within mainstream Sunni Islam. Before al-Ghazali, Sufism had occupied an ambivalent position — orthodox in some forms, suspected of heresy in others, particularly after the execution of al-Ḥallāj in 922 for his ecstatic pronouncements. Al-Ghazali, writing as a senior Shāfiʿī jurist and Ashʿarite theologian, integrated Sufi spiritual psychology with mainstream Sunni law and theology, providing the synthesis that has shaped Sunni piety from his time to the present.
Kenneth Honerkamp, Nakamura Kojiro, and Eric Ormsby have produced significant studies of individual books of the Iḥyāʾ; Timothy Winter (Abdal Hakim Murad) has translated several books and provided extended commentary in works including The Niche for Lights and his Cambridge series.
The Munqidh
The Deliverance from Error — a short autobiographical work composed late in life — traces al-Ghazali's intellectual journey through four groups: the theologians (mutakallimūn), the philosophers (falāsifa), the Ismāʿīlī authoritarians (taʿlīmiyya), and the Sufis. Each, he argues, possesses partial truth but only the Sufi path delivers the certainty (yaqīn) that the rational sciences cannot supply.
The text records a methodological skepticism strikingly parallel to Descartes's — al-Ghazali doubts sense perception, then doubts reason itself, and is delivered from doubt not by argument but by a divine light cast into the heart. W. Montgomery Watt's 1953 translation (The Faith and Practice of al-Ghazali) remains in print; Richard McCarthy's Freedom and Fulfillment (Twayne, 1980) provides a more complete edition of the autobiographical writings.
Reception
Averroes, writing in Andalusia almost a century later, answered al-Ghazali point by point in the Tahāfut al-Tahāfut. The Latin West knew al-Ghazali through partial translations of the Maqāṣid al-Falāsifa (a neutral exposition of philosophy al-Ghazali had written before the Tahāfut), which medieval Latin readers — including Aquinas — mistook for al-Ghazali's own positive views, leading to the curious situation in which al-Ghazali was sometimes cited in Latin Scholastic texts as a fellow philosopher.
In modern scholarship, the rehabilitation of al-Ghazali as a philosophical figure — not merely a destroyer of philosophy — owes much to Marmura, Griffel, Kukkonen, Janssens, and Treiger. Griffel's Al-Ghazālī's Philosophical Theology (Oxford University Press, 2009) demonstrates the extent to which al-Ghazali absorbed and redeployed Avicennan philosophy within his theological framework, complicating the older view of him as a purely anti-philosophical thinker.
Significance
Three contributions define al-Ghazali's importance. The critique of necessary causation in the Tahāfut, seventeenth discussion, formulates a problem that the European Enlightenment would rediscover and that occasionalist theologians from Malebranche to the present have returned to. The integration of Sufism with Sunni mainstream orthodoxy in the Iḥyāʾ shaped the religious life of half the Muslim world for nine centuries. And the autobiographical Munqidh established a form — first-person philosophical and spiritual itinerary — that Augustine had inaugurated and that runs through Descartes's Discourse, Newman's Apologia, and Wittgenstein's notebooks. Al-Ghazali was honored by his contemporaries with the title Ḥujjat al-Islām (Proof of Islam), and the honorific has stuck.