İslam Tetkikleri Dergisi, cilt.16, sa.1, ss.99-137, 2026 (Scopus, TRDizin)
This study analyses the basis of interaction between Judeo-Karaite theology and the Bahshamiyya school of Mu‘tazila by centring on the theological work Kitāb al-Muhtawī of Abū Ya‘qūb Yūsuf b. Ibrāhīm al-Basīr (d. 1040 [?]), who was active during the Golden Age of Karaism. Educated at the Karaite Academy in Jerusalem, Yūsuf al-Basīr composed two major kalām works, Kitāb al-Muhtawī and Kitāb al-Tamyīz, forming the core framework of his theology. It is widely accepted among researchers that he drew inspiration from the Mu‘tazilite doctrine, with a particular affinity for the Bahshamite branch of Basran school. In this respect, he was widely described as a mutakallim, and his thought was characterized as “Jewish-Mu‘tazilite Kalām.” His references to Qādī ‘Abd al-Jabbār (d. 415/1025), the foremost Bahshamite authority, together with evidence that Karaite scholars attended Mu‘tazilite assemblies and the theological analysis of his writings confirm this influence. His refutations of Abu’l-Husayn al-Basrī (d. 436/1044), who diverged from Bahshamiyya on certain issues, further attest to his adherence, showing that he was not only Mu‘tazilite but also committed enough to engage in intra-sectarian debate. This study commences with a brief section on Jewish theology and the historical background of Karaism. Then examines the biography of Yūsuf al-Basīr, based on the available information, and his interactions with the Mu‘tazila, in the context of the works of Basran School’s prominent figures, particularly Qādī ‘Abd al-Jabbār. A comparative analysis is applied, focusing on selected discussions of tawhīd (monotheism) and ‘adl (divine justice) principles in his most substantial work, Kitāb al-Muhtawī, with relevant references to Kitāb al-Tamyīz. The study aims to shed light on the role of the Bahshamiyya – the dominant Mu‘tazilite school of the period – in shaping Jewish theological thought by examining the doctrines of Karaism’s leading representative al-Basīr, a member of the most prominent school of Jewish Kalām in this period.