 Averroes comments on the definition of Physics 201a10–11: “motion is the perfection of that which is in potentiality under the aspect that it is in potentiality” (LC 87D, secundum quod) and says that the movable has two kinds of perfection, a perfection in actuality, and a perfection in potentiality, under the aspect of which it is called motion. Themistius elaborated on the distinction (CAG 5.2: 69:9–70:31 ) and Philoponus emphasized it in his commentary (Philoponus, CAG 16: 342:10–344:7). Averroes could have received it either from Philoponus (Lettinck 1994: 213) or Themistius (see above). He observes that the definition is valid for both eternal and non-eternal classes of motion and he anticipates that the continuity of motion results from the definition itself (LC 88A TC6).