MUKAMMIṢ (also al-Mukammaṣ, the spelling of the name is uncertain), IBN MARWĀN AL-RĀQI (from the city of Raqa, Iraq) AL-SHIRAZI AL- (also known as David ha-Bavli; c. 900), one of the first Jewish philosophers of the Islamic period. Al-*Kirkisani, the Karaite scholar, relates that he was a Jew who began to convert to Christianity when he was a student of Nonnus, a Christian philosopher and physician who lived at Nisibis. However, when he became better acquainted with the dogmas and teachings of Christianity, he composed two polemical works against this religion; nevertheless, from this fact it cannot be deduced with certainty that he returned to Judaism. Be that as it may, Jews and Muslims considered
Al-Mukammiṣ translated Christian commentaries on Genesis and Ecclesiastes and wrote on different religions and sects. A manuscript which contains most of his theological-philosophical work entitled ʿIshrūn Maqālāt ("Twenty Treatises") is extant in the St. Petersburg library. Only a small portion of the Arabic original of the work has been published; this corresponds to one of the sections of a partial Hebrew translation of the work which forms part of Judah b. Barzillai al-Bargeloni's commentary on Sefer Yeẓirah. Al-Mukammiṣ' work deals with such topics as knowledge and truth, substance and accident, the existence of God, His unity and attributes, prophecy, and the Divine commandments. The portions of the work which are extant disclose that, like *Saadiah Gaon (Emunot ve-De'ot, 1:1), al-Mukammiṣ followed, generally speaking, the teachings of the Muslim Mu'tazilites (see *Kalām), though he also accepted some of the views of the Greek philosophers. Like the Mu'tazilites he argued that the attributes of God are not superadded to His essence, so that they would introduce multiplicity into God. God and His attributes are one, and only the shortcomings of human language require that men use a multiplicity of terms in describing His attributes. Attributes describing God must be understood negatively, that is to say, they must be interpreted as stating what God is not, rather than what He is (cf. *God, Attributes of). Al-Mukammiṣ holds further that a "negative theology" similar to his is already found in Aristotle. He rejects the Christian doctrine of the Trinity as false, since it is based on the notion that God possesses a multiplicity of attributes. He calls God the "uncaused cause." The soul, he holds, lives through itself, not through a force in something else. The reward of the righteous and the punishment of the wicked takes place throughout eternity in the World to Come. Describing the history of Christianity, he affirms that this religion has its root in two Jewish sects: the Sadducees and the Jewish pre-Christian sect of the Alkaraya. He points to the contradictions among the various Gospels and shows that these writings contain no laws. Laws were given to Christians only by the apostles Peter and Paul, though Christians see the source of these laws in a secret tradition stemming from Jesus. Since these apostolic laws were few and insufficient, Christians added new laws at the Council of Nicea, and still more laws were added later.
Al-Mukammiṣ wrote extensively about Jewish sects, and his discussion of this topic served, undoubtedly, as an important source for Jewish and Islamic authors.
G. Vajda, in: A. Altmann (ed.), Jewish Medieval and Renaissance Studies (1967), 49–73 (Fr.); Steinschneider, Uebersetzungen, 259–62; Steinschneider, Arab Lit, 37; Baron, Social2 (1958), 91–98, 297–8, 327; Husik, Philosophy, 17–22; Guttman, Philosophies, 74–75.