GAS (Geschichte des Arabischen Schrifttums [History of Arab-Islamic Science]), a vital source in Islamic studies, is an 18-volume work that was formed after examining tens of thousands of manuscripts onsite. It has seriously shaken the frequently-cited claim that “Muslims have not contributed to science.” It aimed to reveal the contributions that Muslim scholars have made to science and technology in the classical period through the written sources belonging to this civilization. In this respect, GAS is the history of thought or the map of the written accumulation of a civilization. 

In this article, we have examined the section of GAS related to theology in a multi-faceted way. In this section, data have been evaluated from many sources such as manuscripts, print sources, those that have not reached the present day, theological books, and nontheological books. Furthermore, in addition, the manuscripts that Fuat Sezgin gave in the works from the libraries in Turkey are examined on a digital platform and in the names of libraries, copyists (mustansihs), in the inventory numbers are detected. In addition, the works that were not included were mentioned in this study as much as possible.

Sezgin’s general claim that written sources have a history dating back to the first century of the hegira is proven when examining the kalam section of GAS. In the early period when a systematic theology had not yet come into being, there were small-scale written documents mainly on certain theological issues such as fate and reduction. After that, it is known that the theological subjects are seen together by means of a type of work called “maqâlât” (articles). In this respect, when the term “kalam” is mentioned, refutations and the history of factions come to mind first. Thanks to this characteristic, books of the maqâlât (articles) type are works that clearly reveal the political framework of the period in addition to relaying theological ideas from historical thinkers to us. In addition, these written sources tell us how the Ahl al-Sunnah belief, which has been regarded as the main source of Islamic doctrine since the time of the Prophet, has become a theological identity. In other words, these works have the ability to offer an idea about the formation of the Ahl-al Sunnah kalam. 

Sezgin states, in the introduction of the kalam section, that the emergence of this science is closely related to early political events. He is correct in this claim because, even though the Mu’tazili thinkers who are known as the first thinkers of Islam come to mind when the origins of the system of kalam is mentioned, Kharijiyyah, Qadariyyah, and Murjiah, who emerged after a number of political developments, also spoke on a theological platform. Therefore, it seems unlikely that the aforementioned groups are purely political groups. 

Sezgin says that the arguments of imamat (imamate), irja (reduction), and other issues (such as the question of the state of the great sinner) are the first arguments following the political events. He cites this finding with reference to Ignác Goldziher, a Western theologian. He also reports, from the German theologian Wellhausen, the issue that the Kharijiyyah were the first founders of kalam. However, it is possible to cite the same findings from sources of Islamic history. Here, it is understood that Sezgin elicited from the orientalist studies while explaining the process of the formation of sciences in GAS. 

Sezgin has stated that doctrine works were written in the point of refutation of Qadariyyah in order to prove that the written sources of kalam extend to the first century. He has also stated that the booklets concerning irja (reduction) and rejection belong to that time. He has mentioned that the qadar (fate) booklets are attributed to Hasan-al Basri and Umar b. Abdulaziz of that period and the booklet named Kitabu’l-irja is attributed to Hasan ibn Muhammad ibn al-Hanefiyyah. But the work named es-Sira, consisting of 52 leaves/warakas which is associated with Salim b. Zekvan, was not mentioned by Sezgin because it had not been found in that period. This work allows us to revise our knowledge about the time of the formation of Murjiah on the one hand, and on the other hand, it is the first text that conveys the disputes between the Kharijiyyah and the Murjiah factions.

As a result, Geschichte des Arabischen Schrifttums is a very valuable work, for researchers, as an important source of information for Islamic studies. Sezgin tried to complete the deficiencies in the encyclopaedic catalogue of Carl Brockelmann in Geschichte der Arabischen Litteratur, which occupies a considerable place among Western sources. But as a result of our analyses in the section about kalam, briefly, the following points drew our attention: 

1. Sezgin has mentioned the authors he believed to be famous in the fields of aqaid (doctrines) and kalam in the kalam chapter. However, he also mentioned some kalam scholars in other chapters. For this reason, many kalam scholars and their works are found in multiple chapters.

2. All the books/booklets of some authors were wanted to be listed whether or not they are related to kalam.

3. While the records are kept for some works, this standard has not been applied to many works.

4. While some authors (whose works are non-existent today) are mentioned, many other authors in the same position have not been mentioned in such a way.

5. An addendum work should be carried out in which revisions of the translations and new editions made after the publication date of the books mentioned in GAS are entered.

6. Considering the recent studies, it seems necessary to write about the history of the kalam literature.