Mubashshir (Mevasser) ha-Levi ben Nissi al-Baghdādī ibn ʿUnāba was a critic of Saʿadya Gaon who lived in Baghdad in the mid-tenth century. His work demonstrates the existence of “internal” rabbinic opponents to tradition, and in particular to Saʿadya’s arguments on behalf of tradition. In his Judeo-Arabic treatise Kitāb Istidrāk al-Sahw al-Mawjūd fī Kutub Raʾs al-Mathība al-Fayyūmī (The Book of the Correction of the Negligence Found in the Books of the Head of the Yeshiva, al-Fayyūmī [Saʿadya]), Mubashshir argues that everything connected with relig…