Al-Ghazali and Descartes: Correlation or Causation?

Christopher Hurtado —  December 1, 2008
Al-Ghazali and Descartes: Correlation or Causation? | Christopher Hurtado


Twelfth century Arab philosopher al-Ghazali used methodological skepticism to answer two of the main problems of philosophy: (1) how knowledge is acquired and, (2) how can one justify that knowledge. Seventeenth century French philosopher Descartes dealt with the problem of doubt in lockstep with al-Ghazali and came up with the same solution (Najm 133). It is evident that Arab philosophy significantly, albeit indirectly, influenced Western philosophy. Is it possible that Descartes was influenced by al-Ghazali? A close comparison of their epistemological methodology and results gives reason to believe that Descartes was influenced by al-Ghazali, but there is no conclusive proof of it (a paper).

Divergent Backgrounds

Al-Ghazali, a prominent philosopher, theologian, and jurist of Sunni Islam, lived between c. 1055 and 1111. In his most famous work, the Incoherence of the Philosophers, he advanced a nominalist critique of Aristotelian science developed later in 14th century Europe. In the Incoherence, he rejected and condemned some of the teachings of Aristotelian philosophy, while accepting and applying others. One of al-Ghazali’s contributions that greatly influenced Latin medieval thought, through the works of Averroes and Jewish authors, was his resolution of seeming contradictions between reason and revelation (“Al-Ghazali”).

Descartes (1596-1650) is considered the first modern philosopher. Like al-Ghazali, Descartes studied law and taught sciences. However, he was a freelancer with no academic or political ties to any institution. In his most famous work, Meditations On First Philosophy, published in 1641, he lays out a philosophical basis for the possibility of the sciences. In so doing, he overthrew Aristotle’s centuries old natural philosophy without forwarding any controversial views, such as the Copernican heliocentric model of the solar system due to the Church’s condemnation of Galileo for doing so. (“Descartes’ Life and Works”).

Convergent Philosophies

There is a link between al-Ghazali and Descartes: methodological use of skepticism (a paper). Both dealt with the problem doubt in like manner and solved the problem in like manner as well (Najm 133). They each created an epistemological platform grounded in subjectivity (Albertini 2).

Al-Ghazali was looking for knowledge of things as they really are, but first he had to determine what knowledge really is. For al-Ghazali, certain knowledge had to be infallible; it had to be completely free from error or deception. In order to determine the possibility of certain and infallible knowledge, al-Ghazali set out to examine the common sources of knowledge: sense perception and necessary truths or truths of reason, Sufic ecstasy or mystic self-transcendence, (Albertini 134-35)

Both al-Ghazali and Descartes describe their encounter with doubt in autobiographical fashion. For both, the process was a fusion of the intimate and personal with the artificial or methodological. Both used doubt as an instrument for the investigation of truth, acknowledging its destructive nature when extended into practical life (Najm 137).

The first two steps in carrying out the process of doubt are common to both al-Ghazali and Descartes. First, they both distrust and ultimately reject sense perception on similar grounds. Secondly, they both distrust and ultimately reject mathematics and necessary truths on similar grounds. They both see mathematical knowledge as subject to doubt on the grounds that (1) calculations and deductions are often made in error and  (2) due to the possibility that one can be deceived by being in a dreaming state or by an evil power greater than oneself (Najm 138).

For both al-Ghazali and Descartes, methodological doubt is analytical and reductionist. Each potential source of knowledge is examined in turn and rejected if dubitable until a true foundation is uncovered. After uncovering that true foundation the next step is the identification of that knowledge that cannot be doubted. Through this process al-Ghazali concluded that the only certain truth is the knowledge of the existence of God (Najm 138).

For Descartes, the thinking self is the foundation of knowledge. However, the Cartesian cognition of the self is neither generally empirical nor logically deducible, but rather intuited. Therefore, both al-Ghazali and Descartes “assert that the sound and solid foundation of all knowledge is recognized only by means of an unmediated encounter with something that presents itself for unqualified and certain belief” (Najm 139).

Descartes centers his quest for truth and true knowledge on God. Only by acknowledging God and his existence can man be secure in his knowledge of physical reality. We can know of the existence of self without God, but only in relation to God can we know the nature of the self.

When we analyze Cartesian thought and that of al-Ghazali we find little difference. Both Descartes and al-Ghazali acknowledge man’s dependence on God for undubitable knowledge. Descartes also points out that man is totally dependant on God for his very being and his continued existence in each moment. Descartes also emphazises faith in divine revelation incomprehensible to reason (Najm 140),

While God and faith are central to Descartes’ manner of dealing with the problem of doubt, it is not a matter of “intuition or mystical vision” for Descartes as it is for al-Ghazali. For Descartes, the “natural light of reason” itself is dependent on God for its validity, and one must accept divine revelations notwithstanding reason. (Najm 141).

Doxographical Exchange

Is it possible that Descartes had direct contact with al-Ghazali’s writings? While it cannot currently be determined that Descartes read al-Ghazali, it is known that translations of his works were available to Europeans during the 16th and 17th centuries, and therefore it cannot it be ruled out. Careful analysis of Cartesian philosophy reveals that many of his ideas seem to have been influenced by Arab philosophy or Islamic theology. While no translated text has been found to satisfy the historians, “discussions and even doxographic rumors” between Europe and Muslim Spain in the 13th and 14th centuries “were probably as important as translated texts” in communicating philosophy (“a paper”). 

Inconclusive Evidence

The achievement of Islamic philosophy and its influence on Western philosophy are generally recognized today. However, the exact nature of this influence has not to date been critically explored. While it is well known that many Arabic books were translated into Latin from the 12th to the 17th century, it is not known exactly how many books were translated, nor how many are extant. Thus, the fact that there is no evidence of the translation of any particular text does not necessarily imply that it was not translated. It may have been translated and the evidence lost. Because our knowledge of the transmission of thought between Arabs and Europeans during the 12th and 17th centuries is incomplete, we cannot rule out the possibility that translations of al-Ghazali’s works or other works influenced by al-Ghazali could have been available to Europeans during those periods of time and that Descartes could have been influenced by those works.


Descartes’ method of doubt is strikingly similar to al-Ghazali’s. Al-Ghazali and Descartes coincide in (1) their reason for and manner of doubt; (2) their use of doubt to establish a sound epistemological foundation; (3) their appeal to divinity to guarantee this foundation; and (4) their claim that this foundation is not subject to proof or demonstration, but rather is immediately perceived. Both philosophers assert the possibility of a solution to the problem of doubt that is neither sensory nor intellectual (Najm 141). Nevertheless, there is no conclusive proof that Descartes was influenced by al-Ghazali since no definitive connection can be made between them.


Works Cited

Albertini, Tamara. “Crisis and Certainty of Knowledge in Al-Ghazali (1058-111) and Descartes (1596-1650).” Philosophy East & West 55(2005): 1-14.
Griffel, Frank. “Al-Ghazali.” Stanford Encyclopedia of Philosophy. 2007. Metaphysics Research Lab, CSLI, Stanford University. 1 Dec 2008 <>.
Najm, Sami M.. “The Place and Function of Doubt in the Philosophies of Descartes and Al-Ghazali.” Philosophy East & West 16(1966): 133-141.
Griffel Frank. “A paper given at the Orient Institute in Beirut on June 30, 2000.”
Smith, Kurt. “Descartes’ Life and Works.” Stanford Encyclopedia of Philosophy. 2007. Metaphysics Research Lab, CSLI, Stanford University. 1 Dec 2008 <>.

Christopher Hurtado

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Christopher Hurtado is President and CEO of Linguistic Solutions and Adjunct Instructor of Philosophy and Political Science at Utah Valley University. He holds a BA in Middle East Studies/Arabic and Philosophy and an MA in Nonproliferation and Terrorism Studies. He coauthored Vacation Spanish: A Survival Guide for Mexico, the Caribbean, Central & South America. He is married to children's book author and homeschool mom, Alysia Gonzalez. Together they have nine children. They are active in their church and in their community.

2 responses to Al-Ghazali and Descartes: Correlation or Causation?

  1. I’m Arab-Muslim & was just reading a short story about imam Al-Ghazali. To my surprise the author quoted from other Arabic books that Othman Al-ka’ak, a Tunisian researcher, found in Descartes’ library a translation of Al-Ghazali’s “Al-Munquith Min al-Dalal” where the phrase: “doupt is the first level of belief” (الشك اول مراتب اليقين) underlined in red with a comment (meaning translated) “adopt this in our methodology”.
    The author mentions that Al-Kaak clearly stated this in the 10th meeting seminar of Islamic Thought, held is Anaba- Algeria 1975. He died during this reunion.
    I never heard of this similarity and that made google to find your post and many others making the comparision.

  2. farah my self waqas ahmad from pakistan i am student of m phil in uloom e islamia in an university in pakistan and i am working on imam ghazal’s and descartes’s view of doubt please help me