This article discusses the possibility of some outlandish tropes from time travel fiction, such as people reversing in age as they time travel or the universe being destroyed because a time traveler kills their ancestor. First, I discuss what type of possibility we might have in mind, detailing ‘close possibility’ as one such candidate. Secondly, I argue that—with only little exception—these more outlandish tropes fail to be closely possible. Thirdly, I discuss whether these outlandish tropes may nevertheless be more broadly (...) possible (e.g., metaphysically or logically possible), arguing that whether they are or not depends upon your favored metaphysics of the laws of nature. (shrink)

possible, your investigation is unlikely ever to get off the ground), there’s no such excuse for philosophers. The philosopher should be unrestricted by fashions in thought, including the unquestioning acceptance of whatever scientific theories are currently dominant. The fact is, however, that in this field and in the philosophy of mind, many.

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)

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)

In this paper I wish to examine the claim that it would be possible for us now to do something which would be the posterior efficient cause of some past event. I am not prepared to discuss the physics of elementary particles, and I will not consider what is sometimes called time reversal. Rather my analysis will be limited to cases in which it is alleged that we, in a world of middle-sized physical objects where most causes precede or are (...) simultaneous with their effects, could conceivably do something so that something else should have happened. I will argue that some of the cases which meet this description are indeed backwards causation if one is prepared to make certain assumptions about time. I will not evaluate these assumptions; rather I will try to clarify them and to make plain their implications for causality. For the argument about backwards causation is most fundamentally, or so I will try to show, an argument about the nature of time. (shrink)

The subject of time travel has been receiving increasing attention in the recent philosophical literature. Most of the articles that deal with it have been concerned to defend the logical consistency of time travel against those who claim that it entails one or more contradictions. Two sorts of defences have been offered. The first sort of defence involves showing that time travel does not entail those consequences which other philosophers allege it does entail. The second sort of defence involves an (...) admission that time travel does indeed involve that which its opponents allege it does involve, e.g., being in more than one place at a time, but arguing that such consequences in no way vitiate the logical consistency of this notion.My first aim in this paper is to provide a defence of time travel of the second sort. More specifically, I want to cut the ground from under an argument which might run thus:Time travel entails that certain effects can precede their causes.It is logically impossible for an effect to precede its cause. (shrink)

The idea that some of God's past beliefs depend on our future actions has a long history, going back to Origen in the third century CE. However, it is not always clear what this idea amounts to, since it is not always clear what kind of dependence is at issue. This paper surveys five different interpretations of dependence and, in each case, considers the implications for the debate over theological fatalism. Along the way, we discuss a number of related issues, (...) including the nature of explanation, the scope of metaphysical grounding, and the possibility of backward causation. (shrink)