This paper argues that the most famous objection to backward time travel can carry no weight. In its classic form, the objection is that backward time travel entails the occurrence of impossible things, such as auto-infanticide—and hence is itself impossible. David Lewis has rebutted the classic version of the objection: auto-infanticide is prevented by coincidences, such as time travellers slipping on banana peels as they attempt to murder their younger selves. I focus on Paul Horwich‘s more recent version of the (...) objection, according to which backward time travel entails not impossible things, but improbable ones—such as the string of slips on banana peels that would be required to stop a determined auto-infanticidal maniac from murdering her younger self—and hence is itself highly improbable. I argue that backward time travel does not entail unusual numbers of coincidences; and that, even if it did, that would not render its occurrence unlikely. (shrink)

This paper addresses a worry about backwards time travel. The worry is that there is something mysteriously inexplicable about the combination of commonplace events that will inevitably conspire to prevent the time traveler from doing something impossible such as killing her younger self. The worry is first distinguished from other problems for backwards time travel concerning its alleged impossibility or improbability. It is then shown that the worry is misplaced: there is in fact no real problem here. Yet the worry (...) has been widely expressed—so a suggestion is also made as to why it is so easy to get into the position of thinking that there is a genuine problem here, when in fact there is not. Finally, in light of the resolution of the inexplicability worry, a new way of dealing with the other two problems for backwards time travel—concerning its alleged impossibility and improbability—is proposed. (shrink)

There is an ancient puzzle about divine foreknowledge and human freedom. If God has already known that you will do a certain thing tomorrow, then it must already be a settled fact that God has known this. Since knowledge entails truth, it must also be a settled fact that you will do it. In that case, you really cannot avoid doing it. If so, then when you do it tomorrow, you won't do it freely. ;This dissertation consists of a careful (...) statement of the puzzle and an examination of its principal solutions. These are fatalism, the view that nothing about the past, present, or future is open, eternalism, the view that God exists outside of time, semantic indeterminism, the view that some propositions are neither true nor false, and Ockhamism, the view that some things about the past are open. ;In Chapter I the puzzle is stated carefully and its solutions are sketched. Chapters II through V each discuss one of the principal solutions. It is argued that fatalism and semantic indeterminism are not adequate solutions to the puzzle. These positions cannot accommodate or adequately explain away our intuition that there is something someone can but will not do. Eternalism is seen to be a formally coherent view, but it also does not provide a satisfying solution to the puzzle. It is argued that Ockham's solution succeeds where the others fail. Finally, it is argued that although Ockham denies the necessity of the past, endorsing his solution does not force one to hold that we can literally change the past. It is concluded that Ockham's solution accommodates our intuitions about freedom and the future without charging a price. (shrink)