and rest. On this method their earlier and later thinkers alike relied, including those who maintain that substances cannot be devoid both of any given genus of accidents and of all its contraries, if it has contraries; that if it has only one contrary, a substance must possess one of the two contraries; and that if an accident having no genus is posited, a substance cannot fail to receive an instance of its kind, provided nothing prevents it from receiving it. This is the most far-reaching of these views, and it is held by the followers of al-Ashʿarī and those who agree with them, such as Qādī Abū Bakr, Qādī Abū Yaʿlā, Abū al-Maʿālī al-Juwaynī, and Abū al-Hasan