 Kilwardby’s theory of sense perception is, on the one hand, Aristotelian because he accepts that our knowledge of the world originates in sense experience; he describes the process of perception as a being-affected. On the other hand, it is Augustinian because he limits the efficient role of the object to the affection of the sense organs; he takes the soul to be the true efficient cause of perception, reacting to the body’s being affected and making in and from itself the images of exterior objects; he grounds his theory on the ontological assumption of a hierarchy of being where only things at the same or higher level can affect each other, which forbids the action of anything corporeal upon something incorporeal. The body feels through the soul (and the soul through itself) because, as to feel is a kind of being-affected, the body cannot affect the soul, but the soul can affect the body.