 The doctrine of temporal parts offers only limited help. The statement that \(c\) is identical to \(s_1\)on day 1 but identical to \(s_2\) on day 2 can be construed to mean that \(c\) is a temporally extended object whose day 1 stage is identical to \(s_1\) and whose day 2 stage is identical to \(s_2\). Since the two stages are not identical, NI does not apply. Similarly, we can regard \(s_2\) as a temporally extended object that overlaps \(c\) on day 2 and \(c'\) on day 3. But unless temporal parts theorists are prepared to defend a doctrine of modally extended objects — objects extended through possible worlds analogous to objects extended in time, there remains a problem. \(s_2\) might have been made of a different piece of clay, as is in fact the case on day 3. That is, it is logically possible for \(s_2\) to fail to coincide with the day 2 stage of \(c\). But it is not logically possible for the day 2 stage of \(c\) to fail to coincide with itself.