This study provides the historical background to, and analysis and translations of, two seminal texts from the medieval Islamic world concerning the univocity of being/existence and a theory of “ambiguous predication” (tashkīk), which is similar to the Thomistic theory of analogy. The disputants are Fakhr al-Dīn al-Rāzī (1149–1210), who defended a theory of the univocity of being, and Naṣīr al-Dīn al-Ṭūsī (1201–1274), who defended the theory of ambiguous predication. While the purported issue is whether a quiddity can cause its own existence, the debate extends further. Rāzī draws on several arguments that “existence” must be predicated univocally of God and creature and then concludes that, given the univocity of “existence,” God cannot be simple, but is a composite of the divine quiddity and distinct attributes. In contrast, Ṭūsī denies that “existence” is said univocally of God and creature and rather is predicated ambiguously/analogously, and then defends divine simplicity.

Catholic Tradition | Contemporary Philosophy | History of Philosophy | Philosophy and Religion