The Incoherence of the Philosophers

A Parallel English-Arabic Text, Translated, Introduced, and Annotated by Michael E. Marmura


Written by al-Ghazali (1058–1111), The Incoherence of the Philosophers (Tahafut al-falasifa) has long been recognized as a classic of Islamic thought. In it, al-Ghazali launches a vigorous attack against twenty philosophical doctrines that he sees as threatening to the Islamic faith. These doctrines include metaphysical claims about the nature and attributes of God, the nature of the world, and the possibility of miracles as well as epistemological assertions about which of these doctrines can and cannot be rationally demonstrated.

Al-Ghazali condemns seventeen of these twenty doctrines as “heretical innovations” (xx) and the remaining three as being in total opposition to Islamic belief. These three are the doctrines that the world is eternal and hence needs no creator; that God does not know particulars but only their universal characteristics—and hence does not know us as individual persons; and that bodily resurrection is impossible. While refuting rational arguments both for and against revealed doctrines, he affirms that such doctrines must be accepted on faith. For al-Ghazali, The Incoherence is more than a speculative discussion of timeless theological questions and philosophical theories; it is a defense and preservation of his religion and a voice of warning to those who have been misled by reliance on (and sometimes misunderstanding of) these philosophical doctrines.

Structure and Translation

The Incoherence of the Philosophers is highly structured. This translation consists of six introductions—five by al-Ghazali and one by the translator, Michael E. Marmura—twenty philosophical exchanges, and a conclusion. Each exchange contains one or more philosophical proofs followed by al-Ghazali’s refutation of the proofs. Al-Ghazali supplements this exchange with a discussion of the philosophers’ anticipated rejoinders followed again by his reply. This method was motivated by al-Ghazali’s belief that he must first summarize and explain the philosophers’ arguments for his readers before he could successfully refute those arguments. Marmura comments that al-Ghazali “explained them so clearly and so well that he rendered philosophical ideas accessible to nonphilosophers” and thus, ironically, made philosophy more popular (xv). Because each exchange builds upon the others without the prior proofs being re-explained, the reader cannot pick and choose which discussions to read but is forced to begin with the first discussion and continue reading straight through the book.

Marmura’s translation of The Incoherence includes a brief biographical sketch, which places the text within the context of al-Ghazali’s life and other works and clarifies his purposes for this text. Other features of this translation include annotations, explanatory notes, the Arabic text and the translated text on facing pages, and numbered lines and paragraphs. To enhance the flow and clarity of the translation, Marmura adds words and phrases that are implied by, but do not appear in, the original text. These additions are bracketed to enable the reader to distinguish what comes directly from the original text and what does not.

These features allow Marmura to distinguish his translation from two other English translations, neither of which, he claims, is adequate for the serious scholar. Most of the text of The Incoherence is in S. Van Den Bergh’s translation of Averroës’ response to The Incoherence, titled The Incoherence of the Incoherence (Tahafut al-Tahafut). Though Marmura lauds Van Den Bergh’s translation as “a major contribution to the study of both al-Ghazali and Averroës,” he asserts that the work contains “serious errors.” He also criticizes S. Kamali’s English translation of The Incoherence for having “its share of inaccuracies” and at times for being “more of a paraphrase than a translation” (xxvi).

Religious and Philosophical Objectives

Al-Ghazali’s objective in The Incoherence is to refute various philosophical doctrines. In his critiques, al-Ghazali denies that philosophers have been able to prove the existence of God, challenges rational arguments attempting to prove the nonembodiment of God, and discredits a theory of the soul that denies bodily resurrection. Confident of the success of his arguments, al-Ghazali demands that those who have been misled by philosophers change their behavior and submit to religious laws. He describes these misled persons as those “‘who repel away from God’s way, intending to make it crooked, who are indeed disbelievers in the hereafter’ [Qur’an 11:19]” (2). Such people follow ancient philosophers by denying “revealed laws and religious confessions” and also by rejecting “the details of religious and sectarian [teaching], believing them to be man-made laws and embellished tricks”(2). Because these misled persons have abandoned their faith, they believe themselves superior to the faithful.

Al-Ghazali believes such followers embrace “the false as true” (2–3), and his basic intent is to correct these misled people by demonstrating the contradictions and confusion—the incoherence—of the philosophers on whom they rely. He explains, “I took it upon myself to write this book in refutation of the ancient philosophers, to show the incoherence of their belief and the contradiction of their word in matters relating to metaphysics; to uncover the dangers of their doctrine and its shortcomings” (3).

According to al-Ghazali, the followers are impressed by the philosophers’ mathematical and scientific certitude and as a result are quickly swept away by metaphysical theories that are unaccompanied by the same level of certainty. The metaphysical realm of study is distinct from scientific and mathematical study in critical ways. Thus, while the ancient thinkers are able to give demonstrations of their mathematical and scientific proofs in such a way that leaves little room for doubt, they fail to provide convincing demonstrations of their metaphysical theories.1

Interestingly enough, al-Ghazali not only refutes the philosophers but also, in certain ways, defends and clarifies their views against the misinterpretations of their followers. While these followers want to reject religious practice and godly belief on account of their leaders’ doctrines, al-Ghazali claims “that all significant thinkers, past and present, agree in believing in God and the last day” (3). If the followers interpreted their philosophers correctly, they would at least hold to a belief in God and, perhaps, to their religious duties. His criticism of the philosophers is not that they reject God, but that “they have fallen into confusion in certain details beyond these principles, erring in this, straying from the correct path, and leading others astray” (3). Nonetheless, he still argues that “certain details” are “heretical innovations” and “utterly irreligious” (xx); The Incoherence is his reply to these innovations.

It is important to note that al-Ghazali does not intend The Incoherence to offer a positive description, explanation, or apology of either Islamic doctrine in general or his personal beliefs in particular. In fact, as observed by Marmura, in the interest of refuting the philosophers, al-Ghazali even persuasively defends doctrines to which he does not personally adhere—for instance, the possibility of the immateriality of the soul (xxvi). Al-Ghazali repeatedly reminds his readers that his task is strictly negative apologetics. His aim is the refutation of philosophical theories that undermine faith, and he undertakes this project only “as one who demands and denies, not as one who claims [and] affirms” (7, emphasis added).

Contemporary Relevance

Although The Incoherence of the Philosophers was written over nine hundred years ago, it addresses several themes that will capture the interest of the twenty-­first-century reader. Two of the more important themes are the proper relationship between science and religion and the nature of causality.

Science and Religion. In his second introduction, al-Ghazali discusses the role that science has relative to religion. He identifies science as central to one of three broad disputes “between [the philosophers] and others of the sects” (5). Eleventh-century theologians often viewed science as a threat to faith and belief in God. However, al-Ghazali claims that the faithful ought not be worried at all about the advances of science and that it is a dreadful mistake for religion to take issue with scientific proofs. With regard to scientific theories, he explains, “Whoever thinks that to engage in a disputation for refuting such a theory is a religious duty harms religion and weakens it” (6). He continues, “The harm inflicted on religion by those who defend it in a way not proper to it is greater than [the harm caused by] those who attack it in the way proper to it. As it has been said: ‘A rational foe is better than an ignorant friend’” (6). The theologian will always lose in such a debate against science and thus makes religion, not science, suspect. The proofs of science are exact and repeatable. Because of this, when theologians position faith against science, anti-religionists find satisfaction and view the opposition in their own favor:

The greatest thing in which the atheists rejoice is for the defender of religion to declare that these [astronomical demonstrations] and their like are contrary to religion. Thus, the [atheist’s] path for refuting religion becomes easy if the likes [of the above argument for defending religion] are rendered a condition [for its truth]. (7)

For this reason al-Ghazali is not concerned with offering any refutations outside of the metaphysical realm. For while the scientific proofs are often indubitable, metaphysical and theological theories are vulnerable to debate and disagreement. Furthermore, science does not pose a threat to religion: “There is no necessity to oppose them in terms of the revealed law in any of these sciences” (166). Speaking of the principles of religion, he similarly states, “It is in this topic and its likes, not any other, that one must show the falsity of their doctrine” (7).

In a day when tensions between scientific models and religious explanations of the world continue to mount, all of us may profit from careful study of al-Ghazali’s reflections on the proper attitudes of religious believers toward science.

The Nature of Causality. Al-Ghazali’s discussion of causality is one of the most interesting discussions in this work, perhaps in part because he offers alternate theories in order to refute those presented by the philosophers. Al-Ghazali addresses theories of cause and effect in defense of the possibility of miracles. Some philosophers, he tells us, deny the occurrence of miracles because they contradict the natural and established flow of cause and its necessary effect. To deny a certain cause its natural and established effect would run contrary to the edicts of natural law.

Al-Ghazali claims that we are too hasty in identifying what is the cause and what is the effect in our world. When two things happen in conjunction with one another, we immediately assume that the first is the cause and the second is the natural and necessary effect. In challenging this assumption, al-Ghazali creates a distinction between an event occurring “with” another event and an event actually occurring “by” another event. “With” claims nothing about one event being the effect of the other. On the other hand, “by” is a claim that one event is the sole source of another event’s occurrence.

So what is this additional, and essential, element that we overlook in all of our observance of cause and effect? It is so essential, al-Ghazali claims, that in all of the events we observe happening “with” one another, not one of the events we observe occurs “by” the other event that we observe (167). For example, we see a person kick a small rock, and the rock goes flying through the air. We observe this happening time and time again. In each instance, a person swings his leg and makes contact with the rock; this we identify as the cause. In conjunction with it, each time we also observe the rock leaving the ground and flying through the air; this we identify as the necessary effect. But how is such an effect assigned to such a cause? We expect a certain effect when given a certain cause out of habit; it is what we have always observed.

Al-Ghazali concludes that it is not irrational for what we habitually expect to be the effect of some cause not to occur when we observe the cause. Thus—and this is his motive for this analysis of causality—the occurrence of a miracle is perfectly rational. We consider an occurrence miraculous because it is different from what we expect, contrary to our experience, and even contrary to what we believe to be natural law.

So, again, what is this essential cause “by” which every effect occurs? Al-Ghazali answers: God. God is responsible for every effect. Which effects will occur with which causes is decided by and empowered by God in every instance. But, al-Ghazali notes, an objector might reply that if God assigns every instance of cause and effect, why do we observe a natural pattern to things? Why does not everything become arbitrary and random so that we cannot expect or be certain of anything? As an example of the chaos implied by al-Ghazali’s deconstruction of our usual notion of causality, the objector might propose:

If someone leaves a book in the house, let him allow as possible its change on his returning home into a beardless slave boy—intelligent, busy with his tasks—or into an animal; or if he leaves a boy in his house, let him allow the possibility of his changing into a dog; or [again] if he leaves ashes, [let him allow] the possibility of its changing into musk. (170)

Al-Ghazali responds to this objection by explaining that God has chosen to act in a consistent manner. Thus, “the continuous habit of their occurrence repeatedly, one time after another, fixes unshakably in our minds the belief in their occurrence according to past habit” (170).


Even with Marmura’s careful translation and helpful notes, The Incoherence of the Philosophers remains an undeniably difficult text.2 Those unfamiliar with philosophy or philosophical problems will likely find reading and rereading this work slow and tedious. Yet The Incoherence is an eminent example of the intellectual depth and rigor of medieval Arabic thought as it engages the reader in one mentally challenging exercise after another. Given al-Ghazali’s negative apologetic aim in The Incoherence, the reader who studies the text to better understand the Muslim faith must study it as part of a much larger scholastic undertaking.3 Within such a framework of additional study, The Incoherence assists in clarifying Islamic doctrine and bringing to light various takes on controversial theological issues in eleventh- and twelfth-century Islam. But even from a study of The Incoherence alone, the reader may appreciate the thought patterns and refutation methods of one of Islam’s most influential thinkers. In the end, this rigorous and dialectical journey through carefully articulated and argued philosophical positions, rebuttals, and rejoinders leaves the reader to contemplate the magnificent and oftentimes mysterious wonder that is God.

About the author(s)

David Paulsen is Professor of Philosophy at Brigham Young University. He received a Ph.D. in philosophy at the University of Michigan. Eric Madsen received a B.S. from Brigham Young University with a double major in philosophy and economics.


1. Al-Ghazali offers his argument against holding confidence in their metaphysics: “We have transmitted this story to let it be known that there is neither firm foundation nor perfection in the doctrine they hold; that they judge in terms of supposition and surmise, without verification or certainty; that they use the appearance of their mathematical and logical sciences as evidential proof for the truth of their metaphysical sciences, using [this] as a gradual enticement for the weak in mind. Had their metaphysical sciences been as perfect in demonstration, free from conjecture, as their mathematical, they would not have disagreed among themselves regarding [the former], just as they have not disagreed in their mathematical sciences” (4).

2. This fact was not lost on al-Ghazali himself, who in an effort to assist the reader provides an appendix (not a part of this translation) to his book setting out the logic and terminology of Islamic logicians, The Standard of Knowledge (Mi’yar al-ism).

3. Fortunately, other works by al-Ghazali and those who respond to and try to refute him are available. For instance, al-Ghazali wrote Al-iqtisad fi al-i’tiqad (Moderation in Belief) which is a constructive exposition of Ash’arite doctrine.

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