He said:

“Change, too, which is said to require an agent of change, includes change in substance, in quality, in quantity, and in place.

According to many people, ‘eternal’ is also applied both to what is eternal in itself and to what is eternal through another. Some changes are considered by certain groups to be possible in what is eternal: for example, the Karrāmiyyah’s acceptance of a newly arising will in the Eternal, and the ancients’ acceptance of generation and corruption in prime matter, although they regard it as eternal. The same applies to intelligibles in relation to the potential intellect, which most of them regard as eternal. Other changes are considered inadmissible, particularly by some of the ancients rather than others.”

He said:

“Likewise, agents include those that act by will and those that act by nature. The manner in which an act may proceed from these two kinds of agent is not the same—I mean with respect to the need for a determining factor. Is this division of agents exhaustive, or does demonstration lead to an agent unlike either those that act by nature or one that acts by the kind of will found in the observable world?”