Averuis' Doctrine of the Unity of the Human Intellect

Averuis' proposal was greeted with derision and hostility in Latin Christendom. The doctrine of the unity of the human intellect was officially condemned by church authorities. Not only was his theory self-evidently false in its own right, but it was also wrong as an interpretation of Aristotle. Averuis must then have had very good reasons for his apparently insane proposal. So what were they?