This is a draft that I posted to my website when I was actively working on it. Later, the project became embrangled in difficulties, evaporated into trivia, or both. So I don't foresee publishing this.
Theodore Sider argues that the possibility of time travel gives us a reason to prefer four-dimensionalist metaphysics (according to which things have temporal parts) over three-dimensionalist metaphysics (according to which things are wholly present at each moment of their careers). This paper considers scenarios in which, although there is no time travel, an individual is simultaneous with its past and future selves. We can use such scenarios to make the same metaphysical point that Sider gleans from time travel. Yet for all we know, we may be living in such a scenario. As such, any mundane moment of our lives might have the same metaphysical upshot as traveling through time.