 On the other hand, there seem to be many cases of objects, which can be identified under a variety of concepts, leading to different life histories. This is termed relativity of identity. For example, a and b may be the same person but not the same child because b is a grown up and no longer a child. Or a and b may be the same lump of clay but not the same statue because b is the lump after it has been reshaped out of its statue shape. These are the most typical kinds of counter examples and Wiggins has responses to both. He deals with the first by invoking the concept of a phase sortal. A phase sortal is one that, by its meaning, denotes part of the life history of something, which, as a whole, is denoted by another sortal. So child is a phase sortal that applies to a phase of the things fully designated by human being. This illuminates an important aspect of the concept of a sortal. It is a necessary condition for F’s being an ultimate sortal that, whenever it applies to something, it applies in a present-tensed manner to the thing through the whole of its existence.