 The mention of angelic existence in the previous paragraph brings up a point seldom noticed in discussions of process theism. Aquinas approximates the Hartshornean distinction between immutable existence and mutable actuality in what he says about the nature of angels. (Thomists might say that Hartshorne approximates Aquinas.) Aquinas holds that angels are not subject to natural decay or destruction for they are incorporeal. Like God, their existence is not affected by the flow of time. They are, however, capable of certain kinds of change. While their existence is constant, they have free will and their knowledge can increase, and in a certain sense, they can move from place to place. Aquinas says that between the unqualified changelessness of God’s eternity and the qualified changeableness of corporeal existence, there is the qualified immutability of angelic being. The technical expression for this is æviternity, which is the mean between the extremes of eternity and time (Summa Theologica I, Q 19, a. 5). One is almost tempted to say that God, as conceived by Hartshorne, is æviternital, except for three important differences: (1) angelic existence is unaffected by time, but it is still contingent, unlike the existence of Hartshorne’s God; (2) angelic freedom includes the freedom to be wicked and Hartshorne does not view that as an option for God; (3) angels are entirely nonphysical, but Hartshorne argues, as we shall see, that God has a body of sorts in the universe itself.