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Did al-Ghazali Kill the Science in Islam?
May 1, 2012

It is a widespread belief among orientalists that one of the major factors, if not the single most important reason, for the decline of science in the Islamic world after its golden age is al-Ghazali's (1058-1111) attack on philosophers that was culminated in his famous book Tahafut al-Falasifah (The Incoherence of Philosophers). Critics of al-Ghazali argue that he challenged philosophers on the grounds that the philosophers could not lay down rational explanations for metaphysical arguments. And this challenge, in a way, stopped critical thinking in the Islamic world.

However, a recent book, Islamic Science and Making of the European Renaissance, by George Saliba calls these arguments into question. This book prompted me to think more critically about this long, accepted argument. Can this prominent scholar of Islam or his famous book, Tahafut al-Falasifah, be held responsible, single handedly, for causing an age of decline in the scientific activities in the Muslim World?

Many orientalists argue that Ghazali's Tahafut is responsible for the age of decline in science in the Muslim World. This is their key thesis as they attempt to explain the scientific and intellectual history of the Islamic world. It seems to be the most widely accepted view on the matter not only in the Western world but in the Muslim world as well. George Saliba, a Professor of Arabic and Islamic Science at Columbia University who specializes in the development of astronomy within Islamic civilization, calls this view the "classical narrative" (Saliba, 2007). However, interesting discoveries in the second half of the twentieth century by historians of science challenged many of the assertions of this classical narrative. An example of such discoveries is the strong connections between Ibn al-Shatir, a famous Damascene astronomer of the fourteenth century, and the Renaissance astronomer Copernicus (Roberts, 1957). If Ghazali had killed science in Islam in the twelfth century, then al-Shatir's work from the fourteenth century could not have been so influential on Copernicus's work. Saliba challenges almost all of the major tenets of the classical narrative on the basis of (1) a critical examination of historical evidence, some of which is quite recent, and (2) the results of his own long-term research in Islamic astronomy.

Saliba's response to the question

In making his argument, Saliba first notes that most of the orientalists operate under the assumption that there must be a sharp conflict between religion and science. This paradigm is probably based on their European experience. To them, al-Ghazali represents the orthodox tradition in Islam and with Tahafut, written in the late eleventh century (between 1091 and 1095), they assume that orthodox religious thought won a decisive victory over rational, scientific thought. From that point on they assume that science in Islam declined, and the Islamic world did not produce anything significant in terms of scientific advancements.

Saliba argues that both of these assumptions are false. First, the European paradigm of conflict between religion and science does not really apply to the Islamic world. The religion of Islam encourages rational and scientific inquiry. Therefore, Muslims see no insurmountable contradictions between their faith and natural laws. Hence, studying religion and studying natural sciences does not create a conflict for Muslims.

Secondly, many of the scientists in the Islamic world were also religious authorities at the same time. A few examples among such scholars are Ibn al-Nafis, Nasir al-Din al-Tusi, Qutb al-Din al-Shirazi ,and Ibn al-Shatir who lived in the thirteenth and fourteenth centuries and made important contributions to such diverse scientific disciplines as mathematics, astronomy, medicine, physics and philosophy. In fact, these scholars were regarded primarily as religious figures by the general public with side interests in sciences. Early Muslim scholars did not hesitate to acquire scientific knowledge wherever they could find it, whether it be in Indian civilization, in Greek civilization, or in Persian civilization. Not only did they acquire these sciences through translation, but they also critically examined them in a comprehensive way. Making corrections and improvements and even introducing new disciplines, they showed a high degree of ownership and maturity. This led to a remarkable period of creativity and rapid advancements in many scientific disciplines in the Islamic world beginning as early as the eighth century (Saliba, 2007).

Contrary to the classical narrative, scientific advancements in the Islamic world did not stop or even slow down after Ghazali. Saliba gives many examples of sophisticated scientific achievements in the Islamic world well after Ghazali. Based on his life-long research in the area, he concludes that the golden age of Islamic astronomy was in the post-Ghazali period from the thirteenth to the sixteenth century. Discoveries by Western historians of science in the second half of the twentieth century show that there are surprisingly strong connections between Copernicus (sixteenth century) and Muslim astronomers from the thirteenth and fourteenth centuries, such as Nasir al-Din al-Tusi and Ibn al-Shatir (Roberts, 1957; Saliba, 2007). These discoveries were shocking to many in the scholarly community who did not expect to find any transfer of knowledge from the Islamic civilization to Europe in the post-Ghazali period. Unfortunately, this new information has not been sufficiently digested by today's scholars and does not yet generally appear in secondary sources.

Saliba also provides examples from other disciplines, such as medicine, that show that a high level of scientific production took place in more than one discipline in the Islamic world in the post-Ghazali period. How is it that such important scientific materials could have been overlooked by the experts? According to Saliba a major reason for modern historians of science to have missed the large amount of scientific production in Islamic world in the post-Ghazali period is the damage caused by the classical narrative. Most historians simply weren't looking for it because the classic narrative stipulated that science in Islam was dead after Ghazali. Even though some new discoveries have been made, there are still many scientific works waiting to be studied from that period. As an example of these omissions, Berggren, the author of Episodes in the Mathematics of Medieval Islam, says that he used this title for his book as opposed to The History of Mathematics in Medieval Islam simply because "Such a book could not be written yet, for so much material remains unstudied that we do not know enough of the whole story" (Berggren, 1986).

The Content and the Method of the Tahafut

Even though Saliba's arguments and evidence are quite convincing to doubt or reject the common narrative, I wanted to go straight to the source-the Tahafut-and have a closer look to see if it might be a book that can be held responsible for killing the science or scientific thought in Islamic civilization.

In Tahafut, Ghazali refutes twenty philosophical doctrines. Using a scientific, or in this context philosophical, method, he first explains those philosophical doctrines before criticizing them. His explanations were so comprehensive and so clear that he made them accessible to non-philosophers, and thus, his ideas became generally better known in the Islamic world. Next, he gave arguments to refute those doctrines. In doing so, he used the very same logical and philosophical principles and arguments that philosophers used in the first place to support their claims. Ghazali mainly argues that the philosophers who proposed the doctrines that conflict with religious principles failed to provide valid and rigorous proofs for their propositions. Hence, he attacked their methodologies using their own tools and principles.

An important point Ghazali makes in Tahafut is that he has no problems with the philosophers' mathematics, astronomical sciences, or logic. He says (Marmura 2000, p. 11):

Regarding mathematical sciences, there is no sense in denying them or disagreeing with them. For these reduce in the final analysis to arithmetic and geometry. As regards to logical sciences, these are concerned with examining the instrument of thought in intelligible things. There is no significant disagreement encountered in these.

Therefore, it is clear that his views could not be used to justify a position against the study of mathematical sciences.

To give the reader a sense of what kinds of philosophical doctrines the Tahafut is concerned with and aims to refute, a selected few out of the twenty are listed below (Marmura 2000, p. 10, 11). The list shows that the questions discussed in Tahafut concern some of the most fundamental issues in theology, particularly in the Islamic theology.

The first problem: On refuting their doctrine of the world's pre-eternity.

The sixth: On refuting their doctrine denying the divine attributes.

The tenth: On showing that upholding a materialist doctrine and the denial of the Maker is a necessary consequence [of what they hold].

The twentieth: On refuting their denial of bodily resurrection and the accompanying bodily pleasures and pains in paradise and hell.

Concluding Remarks

When I discuss the question given in the title of this article with my colleagues, and I argue that it would be unfair to hold Ghazali or Tahafut responsible for the decline of science in Islam, I sometimes hear the objection that "perhaps the content or the method of Tahafut may not justify this conclusion, but this is not how people understood it." But then, one must consider the evidence given by Saliba that there is a large amount of sophisticated scientific production in the Islamic world well after Ghazali, and there is still much more to be discovered. Considering the content of Tahafut and the scientific advances in post-Ghazali period, I have a hard time convincing myself that the classical narrative is the ultimate truth on the matter. This position is supported by the fact that it is usually not realistic to try to explain most major social and historical transformations in terms of a single person, a book, an event, or the like. According to Saliba, the decline in Islamic science was the result of a combination of many internal and external reasons that took place several centuries after Ghazali.

Finally, one may wonder why this question is important or relevant. After all, these things happened a long time ago, and we have to deal with the current realities. One answer would be that there are many lessons to be learned from the history. And of course if the correct version of the history is not available, conclusions will be flawed. If anybody is interested in reviving science and scientific activities in a society, there is much that can be learned from the early Islamic period when there was a remarkable rapid and widespread rise in science, as well as lessons from the later periods of Islamic history when the Islamic world fell behind in scientific production. Some researchers are beginning to realize how much damage the classical narrative has caused in understanding the general history and the development of the modern science. It is always useful to have a critical mind to question and reevaluate assumptions when they do not conform to the evidence.


  • Berggren, J. L. 1986. Episodes in the Mathematics of Medieval Islam, New York: Springer-Verlag.
  • Marmura, Michael E. (translator). 2000. Al-Ghazali The Incoherence of the Philosophers (Tahafut al-Falasifah) Provo: Brigham Young University Press.
  • Roberts, Victor . 1957. "The Solar and Lunar Theory of Ibn al-Shatir: A pre-Copernican Copernican Model," Isis 48:428-432.
  • Saliba, George. 2007. Islamic Science and Making of the European Renaissance, Cambridge: MIT Press.