 As P. T. Geach (1969) noted, the fact that some object \(a\) is not \(F\) before an event occurs but is \(F\) after that event occurs does not mean that the event constitutes, in any deep sense, a change in \(a\). To use a well-worn example, at the time of Socrates’s death Xanthippe became a widow; that is, she was not a widow before the event of her husband’s death, but she was a widow when it ended. Still, though that event constituted (or perhaps was constituted by) a change in Socrates, it did not in itself constitute a change in Xanthippe. Geach noted that we can distinguish between real changes, such as what occurs in Socrates when he dies, from mere changes in which predicates one satisfies, such as what occurs in Xanthippe when Socrates dies. The latter he termed ‘mere Cambridge’ change. There is something of a consensus that an object undergoes real change in an event iff there is some intrinsic property it satisfied before the event but not afterwards.