 Since any change or motion requires two elements, the agent or mover and the patient or movable, Aristotle raises the question whether motion is in the mover or the movable (Phys. III.3). Averroes gives following explanation: the mover acts in so far as it is form, that is to say, in so far as it is in actuality, and the movable is moved in so far as it is in potentiality, therefore the motion “becomes the same perfection of both of them” (LC 92H TC18). Nevertheless, they are two kinds of perfection and Aristotle saw here a dialectical difficulty (aporía logikē, Phys. III.3, 202a21) with which Averroes deals at length (LC 93F–94B TC19) but for Averroes the double character is no difficulty: motion is one and the same according to the subject, different according to the definition (LC 94K TC21).