Temporal Parts: Foreword

Some entities—perhaps all entities—have spatial parts, parts whose spatial location does not coincide with that of the whole. My hands are spatial parts of my body in this sense, and from my window I can only see part of the parade, not all of it. Some entities have temporal parts, too, or so we are inclined to say. The first inning is a temporal part of a ball game in this sense—it occupies a shorter stretch of time, and much more will have to happen before the game is over. The analogy between spatial and temporal parts may be obvious in some cases, especially if time is construed as just another dimension on a par with the three spatial dimensions. But whereas philosophers tend to agree on the idea that ordinary objects and events are spatially extended, and thus have spatial parts, there is controversy concerning their temporal status. On the one hand are philosophers who maintain that all such entities are temporally extended in a literal sense; all such entities persist through time by having different temporal parts at different times just as they all extend across space by having different spatial parts at different places. On the other hand are philosophers who deny this. According to such philosophers some spatially extended entities, such as processes and other events, have temporal parts. Other entities do not; they persist through time by being wholly and completely present at any moment at which they exist at all