This paper explores mutable futurism, the view according to which the future can literally change—that is, it can happen that a future time t changes from containing an event E to lacking it. Mutable futurism has received little attention so far, and the details and implications of the view are underexplored in the literature. For instance, it currently lacks a precise metaphysical model and a formal semantics. Although we do not endorse mutable futurism, our goal here is to strengthen the (...) case for mutable futurism and help establish it as a worthy contender in the debate on the philosophy of time. To attain this goal, we try to make mutable futurism, along with its metaphysical and inferential commitments, as clear as possible, by providing it with a coherent metaphysical model and a plausible semantics, and we show that it can be backed by theoretical reasons. (shrink)

This paper brings two fresh perspectives on Lewis’s theory of time travel. First: many key aspects and theoretical desiderata of Lewis’s theory can be captured in a framework that does not commit to eternalism about time. Second: implementing aspects of Lewisian time travel in a non-eternalist framework provides theoretical resources for a better treatment of time travel to the future. While time travel to the past has been extensively analyzed, time travel to the future has been comparatively underexplored. I make (...) progress on this topic. Along the way, I discuss Lewis’s lesser-known time travel oeuvre, especially his volume of correspondence and lectures on the topic collected in Beebee and Fisher (2020) and Janssen-Lauret & MacBride (forthcoming). Lewis’s body of unpublished work on time travel yields fruitful insights into his broader thinking on the subject. (shrink)

I criticize Lockwood’s solution to the “paradoxes” of time travel, thus endorsing Lewis’s more conservative position. Lockwood argues that only in the context of a 5D space-time-actuality manifold is the possibility of time travel compatible with the Autonomy Principle (according to which global constraints cannot override what is physically possible locally). I argue that shifting from 4D space-time to 5D space-time-actuality does not change the situation with respect to the Autonomy Principle, since the shift does not allow us to have (...) a coincidence-free local dynamical theory. (shrink)

A temporal levels structure for temporal metaphysics is outlined and employed to convey a dilemma threatening the temporal collapse of Growing-Block Theories to their meta-temporal level. The outline further explains how Presentism occupies a privileged position in that temporal levels structure. Moreover, that dilemma relies crucially on the acceptance of productive causation as explaining additions to the growing block, for which it is argued any reasonable growing-block theory should incorporate. The dilemma’s first horn considers growing-block theories where productive causes are (...) only so when present; the second, growing-block theories where productive causes continue being so when past. Either way, growing-block theory collapses into Accruing-Present Theory: whereby all entities survive into succeeding present “blocks” of existents. It is argued, the presentness of surviving entities undermines their intended theoretical role, undercutting motivations for believing accruing-present theses. Ultimately, I recommend rejection of both growing-block and accruing-present theses based on these explanatory inadequacies. (shrink)

This paper elaborates the problem of temporal unity for dynamic presentism and diagnoses the source of that problem in the dynamic presentist’s discarding the traditional C-series in its avoidance of McTaggart’s (1908, 1927) A-series paradox. This C-series provided the fixed structure of time which the transitory aspects of time then followed, and thereby unify those transitory aspects. It then considers ersatzer presentism as an ostensible solution to the problem of temporal unity by providing a new abstract C-series (namely an ersatz-B-series) (...) for dynamic presentism. However, after a closer examination of the details of this proposal, it is found that the ersatz-B-series itself needs to be temporally variable to capture the transitory aspects of time that it is meant to track. Consequently, it cannot provide the fixed structure of time required to unify the transitory aspects of time into a temporal series. It is therefore suggested that dynamic presentists look for a more course-grained determiner of temporal progression to construct the presentist-friendly C-series required to unify their transitory aspects of time. (shrink)

According to the No Alternate Possibilities argument, if time passes then the rate at which it passes could be different but time cannot pass at different rates, and hence time cannot pass. Typically, defenders of the NAP argument have focussed on defending premise, and have taken the truth of for granted: they accept the orthodox view of rate necessitarianism. In this paper we argue that the defender of the NAP argument needs to turn her attention to. We describe a series (...) of worlds that appear to contain differential passage: worlds where time passes at different rates in different subregions. If the NAP argument is to succeed, rate necessitarians must show that each of these worlds is either metaphysically impossible, or does not contain differential passage. (shrink)

Despite a growing number of models argument for the logical possibility of changing the past there continues to be resistance to and confusion surrounding the possibility of changing the past. In this paper I shall attempt to mitigate the resistance and alleviate at least some of the confusion by distinguishing changing the past from what Richard Hanley calls ‘annulling’ the past and distinguishing both from what I shall call ‘otherwising’ the past.

This paper elaborates the problem of temporal unity for dynamic presentism and diagnoses the source of that problem in the dynamic presentist’s discarding the traditional C-series in its avoidance of McTaggart’s A-series paradox. This C-series provided the fixed structure of time which the transitory aspects of time then followed, and thereby unify those transitory aspects. It then considers ersatzer presentism as an ostensible solution to the problem of temporal unity by providing a new abstract C-series for dynamic presentism. However, after (...) a closer examination of the details of this proposal, it is found that the ersatz-B-series itself needs to be temporally variable to capture the transitory aspects of time that it is meant to track. Consequently, it cannot provide the fixed structure of time required to unify the transitory aspects of time into a temporal series. It is therefore suggested that dynamic presentists look for a more course-grained determiner of temporal progression to construct the presentist-friendly C-series required to unify their transitory aspects of time. (shrink)

In some stories, time travellers cannot change the past. It is widely accepted that this is metaphysically possible. In some stories, time travellers can change the past. Many philosophers have explained how that, too, is metaphysically possible. This paper considers narratives where sometimes the past can change and sometimes it cannot, arguing that this is also something that is possible. Further, I argue that we can make sense of stories where some events appear to be ‘fixed points in time’.