and al-Shahrastānī (1), al-Rāzī, and others relate concerning the doctrines of the philosophers is drawn from the writings of Ibn Sīnā.
Yet there are other distinct schools of philosophers besides these. Thus, Qadi Abū Bakr, in Daqāiq al-Kalām (2), and before him Abū al-Hasan al-Asharī, in his book Maqālāt Ghayr al-Islāmiyyīn (3)—a substantial work larger than Maqālāt al-Islāmiyyīn—cite many doctrines of the philosophers that are not mentioned by those who draw upon Ibn Sīnā. Other figures besides al-Asharī did likewise, such as Abū Isā al-Warrāq (4), al-Nūbakhtī (5), Abū Alī (6), Abū Hāshim (7), and a great many theologians and philosophers.
The point is that one may benefit from the books of the theologians through the refutations they direct against one another. This, however, is unnecessary for anyone who has no need to refute a false doctrine because it has never occurred to him, no one presents it to him, and he does not read any book containing it. Nor does it benefit anyone who does not understand the refutation. Indeed, one who learns of the specious argument but does not recognize its falsity may be harmed by it.
The point here, however, is that this is the knowledge contained in their books: they refute one falsehood with another, and both positions are false. For this reason, such discourse was condemned and prohibited by the Salaf and the imams. Yet many of them—or most of them—do not realize that what they say is false.