 Averroes had to go back to the issue in his interpretation of Book VIII.3, 253b6–31, where Aristotle denies the processes of increase and decrease and of qualitative change to be always  occurring[10].  His commentary is unusually long (LC 358D–360F TC23) and Averroes asks himself why Aristotle had to refute something apparently obvious. He conjectures that the reason is because continuity is hidden in quantitative and qualitative motions (in motibus augmentationis et alterationis, LC 359H). He gives the Aristotelian example of the stone being worn away by the drop of water and then discusses how the process takes place. The stone loses each time a certain part, and not whatever part but the first actually created one (prima pars facta in actu, LC 359G), and the same rule applies to the falling drops of water. They are complete parts. Averroes recalls that Aristotle had said in Book VI (234b10–20) that what changes does not have a first part, and he sees there a difficulty but he explains: