Abstract

In his well-known time travel story, David Lewis claims that there is a sense in which Tim can go back in time and kill his Grandfather and a (more inclusive) sense in which he cannot. Lewis describes Tim’s predicament as semi-fatalist, but holds that this does not compromise Tim’s freedom or his ability to kill Grandfather. I argue that if semi-fatalism is true of Tim, it is true of everyone, and that this is a troubling conclusion.