Sincetherewerethreekindsofsubstance，twoofthemphysical
andoneunmovable，regardingthelatterwemustassertthatitis
necessarythatthereshouldbeaneternalunmovablesubstance。For
substancesarethefirstofexistingthings，andiftheyareall
destructible，allthingsaredestructible。Butitisimpossiblethat