Abstract

Are there difficulties raised by the idea of backwards time travel—travel to earlier times—that are peculiar to objects? By ‘object’ in this context I mean something that takes up space, that typically prevents other items in the same category from occupying the same space, and for which it is generally thought appropriate to talk in terms of persistence conditions. One such problem is raised in H. G. Wells’ The Time Machine, but highlighted in the philosophical literature only very recently, by William Grey. Consider Tim, who boards his time machine and, at 12 noon precisely, presses the button to send him back into the past. At any moments after noon, both Tim and the machine have ceased to exist.