From Medievalists.net’s interview with University of Notre Dame professor Therese Scarpelli Cory:
Take for example, the Aquinas and ‘the Arabs’ Project, which is less than a decade old. The project sponsors conferences, seminars, and publications, studying how Aquinas and his contemporaries appropriated concepts from newly-translated texts from the Jewish and Islamic tradition. From this research, an interesting new picture is emerging. In the past, the assumption has been that Aquinas is basically influenced by Augustine and Aristotle, whom he tries to reconcile with each other. We’re now realizing that this story is much too simplistic. For instance, when thirteenth-century Latin thinkers read Aristotle, they’re interpreting and even critiquing him with the help of commentaries translated from Arabic, tapping into centuries of pre-existing debate. As a result, the introduction of Aristotle into Latin Christianity isn’t just the translating of some interesting new text. Rather, it’s an encounter with a rich and diverse school of philosophical thought in which Aristotelian and pseudo-Aristotelian concepts have been interpreted and expanded through centuries of interpretation and debate.
Through textual comparisons, we’re also learning that Islamic thinkers like Averroes (Ibn Rushd) and Avicenna (Ibn Sina) have far more influence on Aquinas’s thought than was previously realized. He frequently adopts concepts they developed, even from some of the very theories to whose conclusions he most strongly objects. For instance, he famously sharply criticized Averroes for positing that there is just one universal thinking mind (a.k.a. “the Material Intellect”) that all humans share. But if you take a closer look at Aquinas’s own theory of intellectual abstraction, he uses a model directly traceable to Averroes.