 However, doubts can arise whether the proposition that all body has only finite power applies to the celestial body or not (LC 426H). If it applies, the celestial body has a finite power, and it is destructible. If it does not, the resulting motion will be instantaneous. The issue is very difficult and very exhaustive (multum scrupulosa, LC 426K). Averroes knows the opinions of Alexander of Aphrodisias, Johannes Philoponus and Avicenna. Alexander affirmed that the celestial body acquires eternity from its mover; Philoponus denied it and sustained that it is corruptible because its potentiality, power, is finite. Avicenna would follow Alexander and claim that the heavens are necessary because of another but its movers are necessary because of themselves, and we understand: they are eternal (LC 426LM). Then Averroes expresses his view on the celestial body and its potentiality: