that are rational and conclusive, about which no rational person can have any doubt. We have answered their doubts with responses that establish certainty, and we have no need to repeat them. That being so, this objection falls away.”

The discussion to which he referred appears in his treatment of hearing and sight—that is, perception. He devoted the first section to its nature, then said:

“Section Two: How This Perception Occurs

“The Mu‘tazilah maintain that whenever the sensory faculty is sound, the visible object is present, neither excessively near nor excessively far away, neither extremely small nor subtle, with no dense barriers between the observer and the visible object, and with the object facing the observer or in an equivalent position, perception must necessarily occur when all these conditions are met. In our view, however, this is not necessary. This is also the position of Abū al-Hudhayl of the Mu‘tazilah.”

He then cited two arguments supporting their position, before saying: “As for those who disagree, they adopt two lines of argument on this question