Al-Ghazali: Philosophy, Quotes & Legacy

Biography

Abu Hamid Muhammad ibn Muhammad al-Ghazali was born in 1058 in Tus, in the region of Khorasan in northeastern Iran. His father, a Sufi-inclined wool spinner, died when al-Ghazali was young, leaving him and his brother to be educated through the support of a Sufi friend. Al-Ghazali studied the religious sciences — jurisprudence, theology, and dialectic — in the great centers of the Islamic East, first at Tus and then at Nishapur, under the distinguished Ash'arite theologian al-Juwayni. By the time he was thirty-three, his reputation had reached the Seljuk vizier Nizam al-Mulk, who appointed him to the most prestigious academic position in the Islamic world: professor at the Nizamiyya college in Baghdad, where he taught law and theology to large audiences and engaged in public disputation.

In 1095, at the height of his career, al-Ghazali suffered the famous crisis that transformed his life. In his spiritual autobiography, Deliverance from Error, he describes a paralysis of doubt that attacked the very foundations of knowledge: he could not distinguish truth from illusion, and his skepticism extended even to the deliverances of the senses and reason. The crisis was resolved, he reports, not by argument but by "a light which God cast into my breast" — an experience that convinced him that certainty comes not from demonstration but from direct religious experience. He resigned his professorship, left Baghdad under the pretext of pilgrimage, and spent the next decade in Damascus, Jerusalem, Hebron, and his hometown of Tus, practicing the ascetic and contemplative life of a Sufi.

He returned to teaching at the end of his life, at the Nizamiyya college in Nishapur, but he died in 1111 in Tus, leaving behind the corpus that made him the most influential theologian of the Islamic tradition: the Revival of the Religious Sciences (Ihya' 'Ulum al-Din), the Incoherence of the Philosophers (Tahafut al-Falasifa), and the Deliverance from Error.

Historical Context

Al-Ghazali wrote at a moment of crisis in the intellectual life of Islam. By the eleventh century, the philosophical tradition of al-Farabi and Avicenna had produced a complete rationalist system, and its claims — the eternity of the world, the derivation of the universe by necessary emanation from God, the denial of God's knowledge of particulars, and the denial of bodily resurrection — appeared to many theologians to contradict the Qur'an. At the same time, the growth of Ismaili and esoteric movements had created a general crisis of authority: which teaching, and which teacher, could be trusted? Al-Ghazali's great achievement was to respond to both crises: to expose the inadequacy of the philosophers' claims to certainty, and to defend the authority of prophetic revelation and of the Sufi path as the true road to certainty.

The intellectual context also included the rivalry between the two great theological schools of Sunni Islam, the rationalist Mu'tazilites and the Ash'arites, and al-Ghazali's formation was Ash'arite. His work is best understood as a synthesis: he used the tools of Greek logic and dialectic (which he had mastered thoroughly) to defend the faith against the philosophers, and he used the experiential authority of Sufism to ground the faith against the skepticism of the intellectuals. He has been described, not unjustly, as the greatest theologian of Islam — the figure who defined the terms of orthodox belief for centuries to come.

Core Ideas

The Incoherence of the Philosophers

Al-Ghazali's most famous work, the Incoherence of the Philosophers (c. 1095), is a systematic critique of the philosophical system of Avicenna, whom he regarded as the best representative of the tradition. He identifies twenty positions held by the philosophers, of which seventeen are heretical innovations and three are outright unbelief: the eternity of the world, the denial of God's knowledge of particulars, and the denial of bodily resurrection. The book's method is dialectical: it shows, point by point, that the philosophers' demonstrations do not actually demonstrate, and that their conclusions rest on assumptions they cannot justify. The most famous discussion is the "occasionalism" argument against the philosophers' account of causation: the connection between cause and effect is not necessary but habitual, and God is the true cause of everything.

The Critique of Reason

Al-Ghazali's crisis, described in the Deliverance from Error, is the most famous episode of philosophical doubt in the Islamic tradition. He narrates how he sought certainty beyond doubt — a certainty so firm that it could not be shaken by any argument — and how he found it neither in the senses (which deceive) nor in reason alone (which depends on unproven first principles), but only in the "light" of direct religious experience. His conclusion was not that reason is worthless but that it has limits: reason can establish the existence of God and the coherence of the faith, but it cannot reach the certainty of the heart, and the philosophers' mistake was to think that demonstration alone could give the whole truth. This position — reason affirmed but bounded, experience given the final word — is the doctrinal core of his thought.

The Revival of the Religious Sciences

The Revival of the Religious Sciences (Ihya' 'Ulum al-Din), his masterwork of the decade of withdrawal, is a comprehensive account of the spiritual life of Islam. It is organized around the worship, the customs, the "ways of perdition" (the vices of the soul), and the "ways of salvation" (the virtues and the contemplative ascent). Its thesis is that the outward observance of the law is the shell of religion, while the transformation of the heart is its kernel: knowledge that does not issue in action is wastefulness, and the goal of the religious life is the purification of the soul through which the divine light is received. The Ihya is the bridge between orthodox theology and Sufism, and it made the contemplative life respectable within the mainstream of Sunni Islam.

The Deliverance from Error

The Deliverance from Error (al-Munqidh min al-Dalal), written near the end of his life, is al-Ghazali's spiritual autobiography and his classification of the seekers after truth: the theologians, the philosophers, the esotericists, and the Sufis. His verdict is that only the Sufis have found the truth they sought — not by argument but by "taste" (dhawq), the direct experiential knowledge of God. The book is one of the great documents of religious psychology, and its account of the crisis of doubt has made al-Ghazali, alongside Descartes, one of the classic witnesses to the problem of certainty.

Philosophy

Al-Ghazali's place in the history of philosophy is paradoxical: he is the philosopher who attacked philosophy, and the attack was so effective that it defined the subsequent fate of the discipline in the Islamic world. His critique of Avicenna was devastating in the Islamic East: after the Incoherence of the Philosophers, the philosophical tradition of the Islamic world was absorbed into theology and mysticism, and independent falsafa declined. In the Latin West, by contrast, his works helped provoke the very rationalism he opposed: the Latin scholastics, reading the Incoherence alongside Averroes's reply, developed the mature medieval debate about faith and reason.

His philosophy is best characterized as a critical theology: reason is a necessary instrument, but its claims to autonomy are rejected. This is why his relation to the philosophers is not the relation of an ignorant enemy but of a master who has passed through their school. He had mastered Avicenna's system thoroughly — his summaries of the philosophers, preserved in his works, are among the clearest expositions of their views — and his refutation is conducted on their own ground. His legacy in Islam was to secure the orthodoxy of the Ash'arite theology and the legitimacy of Sufism, and to set the boundary within which Islamic intellectual life would develop for the next seven centuries.

Major Works

Al-Ghazali's major works include the Incoherence of the Philosophers (Tahafut al-Falasifa, c. 1095), his critique of Avicenna; the Revival of the Religious Sciences (Ihya' 'Ulum al-Din, c. 1096–1100), his four-volume masterwork of the spiritual life; the Deliverance from Error (al-Munqidh min al-Dalal, c. 1108), his autobiography; and the Alchemy of Happiness (Kimiya-yi Sa'adat), the Persian summary of the Ihya written for a wider audience. His juridical works, such as the Mustasfa on the principles of jurisprudence, complete the corpus of one of the most prolific and influential writers in the history of Islam.

Famous Quotes

Al-Ghazali's most famous passage is the account of his doubt in the Deliverance from Error: "I said to myself: my aim is simply knowledge of the real things... I began to think: since I cannot attain to certainty by the senses, perhaps, as the philosophers say, only rational demonstration can give it." His most famous aphorism, from the Alchemy of Happiness, is that "knowledge without action is wastefulness and action without knowledge is foolishness." And his summary of the Sufi way captures the experiential core of his thought: "I learned with certainty that it is the Sufis who walk in the way of God, whose life is the best life and whose ethics the purest ethics."

Related Thinkers

Al-Ghazali's thought is defined by his engagement with Avicenna, the greatest of the Islamic philosophers, whose system he refuted in the Incoherence of the Philosophers, and by the reply of Averroes, whose Incoherence of the Incoherence defended the philosophers. His synthesis of theology and Sufism shaped the mainstream of Sunni Islam, and his influence extended into the Latin West, where Thomas Aquinas and the scholastics debated his arguments alongside those of the philosophers he attacked. His account of the limits of reason and the priority of religious experience remains one of the classic statements of the relation between faith and philosophy.

Sources

• Stanford Encyclopedia of Philosophy, "Al-Ghazali" (plato.stanford.edu/entries/al-ghazali)
• Al-Ghazali. The Incoherence of the Philosophers. Trans. Michael Marmura. Provo, UT: Brigham Young University Press, 1997.
• Al-Ghazali. Deliverance from Error. In The Faith and Practice of Al-Ghazali, trans. W. Montgomery Watt. London: Allen and Unwin, 1953.
• Griffel, Frank. Al-Ghazali's Philosophical Theology. New York: Oxford University Press, 2009.