Most likely born in Baghdad, the Jewish philosopher Sa’d ibn Mansur Ibn Kammuna died in 1284; his writings, all of which were in Arabic, influenced both Jewish and Muslim thinkers of the era. His thought draws upon Sufism, the Islamic philosophers Ibn Sina and al-Ghazali, and the great Sephardi philosophers Judah Halevi and Moses Maimonides, among many other sources. Describing one of Ibn Kammuna’s books, recently translated into English by Tzvi Langermann, Alan Brill writes:
Ibn Kammuna’s Subtle Insights Concerning Knowledge and Practice is a goldmine of ethics, ritual, piety, and religious thought, [filled with] valuable [information] about the medieval Jewish experience and its culture.
Written for the newly appointed Muslim governor of Isfahan, [a city now in Iran and then ruled by an offshoot of the Mongol empire], this compact treatise and philosophical guidebook includes a wide‑ranging and accessible set of essays on ethics, psychology, political philosophy, and the unity of God.
To Kammuna, [society is composed of] two elements: the common people who follow religion based on the authority of prophecy and the philosopher- intellectuals who have a philosophic religion. This book presents what Langermann calls “Abrahamic philosophic piety,” [based on the twin] principles of God and prophecy. Allah, Theos, and the God of the Hebrew Bible are automatically assumed to be the same universal Deity.
Yet, adds Langermann, in conversation with Brill, the abstract universalism Ibn Khammuna embraces in this book is not, at least on its own, representative of his thought as a whole:
[Ibn Khammuna’s book comparing the three monotheistic religions], Examination of the Three Faiths, has a distinctly pro-Jewish bias, which was not lost on Christian and Muslim readers. It is not overtly polemical; he does not attack any other religion. . . . However, Judaism does come out looking the best of the three in that book. Similarly, his relatively unknown treatise comparing Rabbinic Judaism with Karaism, [a sect that rejected the Talmud and the rabbinic tradition], clearly favors the Rabbinites.
Read more on Book of Doctrines and Opinions: https://kavvanah.wordpress.com/2020/05/11/interview-with-tzvi-langermann-about-ibn-kammuna/