The Philosophers and Their Errors

Al-Ghazali's engagement with the philosophers was serious and sustained. He spent roughly two years studying Aristotelian and Neoplatonic philosophy as it had been transmitted and developed by al-Farabi and Ibn Sina, mastering their logic, metaphysics, natural philosophy, and ethics without the guidance of a teacher, working entirely from their texts. This was a remarkable feat of independent scholarship, and al-Ghazali is admirably honest about what he found valuable. The philosophers' logic, he concedes, is largely sound and useful. Mathematical and natural scientific portions of their work, where they proceed by sound demonstration, can be accepted without theological risk. He praises their epistemology where it aligns with reason and does not fault them simply for being philosophers.

However, al-Ghazali found that the philosophers imported metaphysical commitments into their system that contradicted Islamic doctrine and could not be demonstrated by the methods they claimed to use. He catalogued twenty points of disagreement between the philosophers and the religion, and in his later work, the Tahafut al-Falasifa, he attacked the purported demonstrations for these positions and showed them to be, at best, probable arguments dressed up as proofs. Three of these twenty points were particularly serious in his judgment: the philosophers' claim that the world is eternal (qidam al-alam), having no beginning in time; their claim that Allah knows only universals and not particulars; and their denial of bodily resurrection. These three positions, al-Ghazali argues, contradict the clear and definitive teachings of Islam and therefore constitute kufr in those who hold them while claiming to be Muslim.

Al-Ghazali's charge of kufr against these positions was controversial then and has been discussed by scholars ever since. His target was not philosophy as such but specific metaphysical claims that the Islamic philosophical tradition had borrowed from Aristotelian sources and presented as rationally necessary truths. His argument in the Tahafut is that these claims are not demonstrated at all: the arguments for the eternity of the world, for instance, rest on assumptions about the nature of time and causality that are themselves contestable and that al-Ghazali contests with considerable skill. If the demonstration fails, the theological compromise it seemed to require disappears along with it. One is then free to hold the Islamic position on these matters without any rational embarrassment.

Beyond the philosophical critique, al-Ghazali saw a deeper problem with the philosophers' approach. Like the theologians, they addressed the intellect while neglecting the inner life. Philosophy could produce learned men with sophisticated views about the nature of existence, but the path to Allah requires more than right opinions about metaphysics. It requires the purification of the soul, the conquest of the ego's desires, and the cultivation of states of the heart that philosophical training does not even acknowledge as genuine objects of knowledge. The philosophers' universe is cold and impersonal: a God who knows only universals and whose relationship to the world is mediated through a chain of intellects is not the Allah of the Quran who is closer to the human being than his jugular vein. Al-Ghazali left the philosophers' school intellectually stimulated but spiritually no closer to what he sought.