This paper argues for the following disjunction: either we do not live in a world with a branching temporal structure, or backwards time travel is nomologically impossible, given the initial state of the universe, or backwards time travel to our space-time location is impossible given large-scale facts about space and time. A fortiori, if backwards time travel to our location is possible, we do not live in a branching universe.

Many defenders of the possibility of time travel into the past also hold that such time travel places no restrictions on what said time travelers can do. Some hold that it places at least a few restrictions on what time travelers can do. In attempting to resolve this dispute, I reached a contrary conclusion. Time travelers to the past cannot do other than what they in fact do. Using a very weak notion of can, I shall argue that the correspondingly (...) strong cannot do otherwise applies in the case of backwards time travel. I defend this result from objections. (shrink)

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)