Averroes is well-known for his controversial thesis that there is only one separate intellect for all humankind. This article provides a detailed analysis of Averroes’s Unity Argument from his Long Commentary on De Anima, which argues from unified intelligible concepts to a single transcendent intellect. I set out the Unity Argument in its textual and philosophical context, explain exactly how the argument works on a new interpretation of its infinite regress, and offer some brief suggestions as to how it might (...) be further evaluated in light of alternative ancient and medieval theories. Ultimately, I demonstrate that the Unity Argument is Averroes’s most important philosophical argument for his distinctive view of intellect. (shrink)