 Motion in place is one kind of change but it is prior to the other kinds, to change in quality or alteration, to change in quantity or growth and decrease, and to change in substance, or coming-to-be and passing-away. The latter is the main subject matter of Aristotle’s De generatione et corruption and Averroes’s Middle and Short commentaries insist on the necessity of motion in place as the condition for substantial change (Eichner 2005: 115–117). Local motion brings mover and movable together by being in contact (tamāss). When this occurs in the elements, i.e., the four natural bodies, they interact so that each one is agent and patient. Within local motion circular motion is the most perfect form and we will see how the universe is moved by circular motion. 