We have argued elsewhere that moral responsibility over time depends in part upon the having of psychological connections which facilitate forms of self-control. In this chapter we explore the importance of mental time travel - our ordinary ability to mentally travel to temporal locations outside the present, involving both memory of our personal past and the ability to imagine ourselves in the future - to our agential capacities for planning and control. We suggest that in many (...) individuals with dissociative disorders, forms of amnesia, or other frontal lobe damage, our capacity for mental time travel is impaired, resulting in commensurate losses to agency autonomy, and a forensic condition essential for holding persons responsible: in legal terms, the capacity for mens rea. (shrink)

What is it to remember an episode from one’s past? How does episodic memory give us knowledge of the personal past? What explains the emergence of the apparently uniquely human ability to relive the past? Drawing on current research on mental time travel, this book proposes an integrated set of answers to these questions, arguing that remembering is a matter of simulating past episodes, that we can identify metacognitive mechanisms enabling episodic simulation to meet standards of reliability sufficient (...) for knowledge, and that the subjective experience of reliving the past is a precondition for the reliability of simulational remembering. The resulting account of memory, memory knowledge, and their evolution will be of interest both to philosophers interested in empirically-informed approaches to memory and to psychologists interested in the philosophical implications of empirical memory research. (shrink)

Mental time travel is defined as projecting the self into the past and the future. Despite growing evidence of the similarities of remembering past and imagining future events, dominant theories conceive of these as distinct capacities. I propose that memory and imagination are fundamentally the same process – constructive episodic simulation – and demonstrate that the ‘simulation system’ meets the three criteria of a neurocognitive system. Irrespective of whether one is remembering or imagining, the simulation system: acts on (...) the same information, drawing on elements of experience ranging from fine-grained perceptual details to coarser-grained conceptual information and schemas about the world; is governed by the same rules of operation, including associative processes that facilitate construction of a schematic scaffold, the event representation itself, and the dynamic interplay between the two ; and is subserved by the same brain system. I also propose that by forming associations between schemas, the simulation system constructs multi-dimensional cognitive spaces, within which any given simulation is mapped by the hippocampus. Finally, I suggest that simulation is a general capacity that underpins other domains of cognition, such as the perception of ongoing experience. This proposal has some important implications for the construct of ‘MTT’, suggesting that ‘time’ and ‘travel’ may not be defining, or even essential, features. Rather, it is the ‘mental’ rendering of experience that is the most fundamental function of this domain-general simulation system enabling humans to re-experience the past, pre-experience the future, and also comprehend the complexities of the present. (shrink)

Time travel is metaphysically possible. Nikk Effingham contends that arguments for the impossibility of time travel are not sound. Focusing mainly on the Grandfather Paradox, Effingham explores the ramifications of taking this view, discusses issues in probability and decision theory, and considers the potential dangers of travelling in time.

This paper is an enquiry into the logical, metaphysical, and physical possibility of time travel understood in the sense of the existence of closed worldlines that can be traced out by physical objects. We argue that none of the purported paradoxes rule out time travel either on grounds of logic or metaphysics. More relevantly, modern spacetime theories such as general relativity seem to permit models that feature closed worldlines. We discuss, in the context of Gödel's infamous (...) argument for the ideality of time based on his eponymous spacetime, what this apparent physical possibility of time travel means. Furthermore, we review the recent literature on so-called time machines, i.e., of devices that produce closed worldlines where none would have existed otherwise. Finally, we investigate what the implications of the quantum behaviour of matter for the possibility of time travel might be and explicate in what sense time travel might be possible according to leading contenders for full quantum theories of gravity such as string theory and loop quantum gravity. (shrink)

In "Changing the Past" (2010), Peter van Inwagen argues that a time traveler can change the past without paradox in a growing block universe. After erasing the portion of past existence that generates paradox, a new, non-paradox-generating block can be "grown" after the temporal relocation of the time traveler. -/- I articulate and explore the underlying mechanism of Van Inwagen's model: the time traveler's control over the location of the objective present. Van Inwagen's model is aimed at (...) preventing paradox by changing the past, but it achieves something broader than paradox avoidance: it gives tools for a new model of time travel. I use van Inwagen's tools to develop a new kind of time travel in which in which the location of the objective present is shifted by the time traveler. I call this type of time travel Movable Objective Present, or MOP. After defining MOP, I argue that it is compatible with any theory of time that accepts hypertime, including presentism and moving spotlight theory. (shrink)

This article argues that existing approaches to programming ethical AI fail to resolve a serious moral-semantic trilemma, generating interpretations of ethical requirements that are either too semantically strict, too semantically flexible, or overly unpredictable. This paper then illustrates the trilemma utilizing a recently proposed ‘general ethical dilemma analyzer,’ GenEth. Finally, it uses empirical evidence to argue that human beings resolve the semantic trilemma using general cognitive and motivational processes involving ‘mental time-travel,’ whereby we simulate different possible pasts and (...) futures. I demonstrate how mental time-travel psychology leads us to resolve the semantic trilemma through a six-step process of interpersonal negotiation and renegotiation, and then conclude by showing how comparative advantages in processing power would plausibly cause AI to use similar processes to solve the semantic trilemma more reliably than we do, leading AI to make better moral-semantic choices than humans do by our very own lights. (shrink)

Ryan Wasserman explores a range of fascinating puzzles raised by the possibility of time travel, with entertaining examples from physics, science fiction, and popular culture, and he draws out their implications for our understanding of time, tense, freedom, fatalism, causation, counterfactuals, laws of nature, persistence, change, and mereology.

Kadri Vihvelin, in "What time travelers cannot do" (Philos Stud 81: 315-330, 1996), argued that "no time traveler can kill the baby who in fact is her younger self, because (V1) "if someone would fail to do something, no matter how hard or how many times she tried, then she cannot do it", and (V2) if a time traveler tried to kill her baby self, she would always fail. Theodore Sider (Philos Stud 110: 115-138, 2002) criticized Vihvelin's (...) argument, and Ira Kiourti (Philos Stud 139: 343-352, 2008) criticized both Vihvelin's argument and Sider's critique. I present a critique of Vihvelin's argument different from both Sider's and Kiourti's critiques: I argue in a novel way that both V1 and V2 are false. Since Vihvelin's argument might be understood as providing a challenge to the possibility of time travel, if my critique succeeds then time travel survives such a challenge unscathed. (shrink)

In this paper, I argue that the thesis that time travel is logically possible, is inconsistent with the necessary truth of any of the usual ‘open futureobjective present’ models of the universe. It has been relatively uncontroversial until recently to hold that presentism is inconsistent with the possibility of time travel. I argue that recent arguments to the contrary do not show that presentism is consistent with time travel. Moreover, the necessary truth of other (...) open future-objective present models which we might, prima facie, have supposed to be more amenable to the possibility of time travel, turn out also to be inconsistent with this possibility. (shrink)

Future-biased individuals systematically prefer positively valenced events to be in the future (positive future-bias) and negatively valenced events to be in the past (negative future-bias). The most extreme form of future-bias is absolute future-bias, whereby we completely discount the value of past events when forming our preferences. Various authors have thought that we are absolutely future-biased (Sullivan (2018:58); Parfit (1984:173) and that future-bias (absolute or otherwise) is at least rationally permissible (Prior (1959), Hare (2007; 2008), Kauppinen (2018), Heathwood (2008)). The (...) permissibility of future-bias is often held to be grounded in the structure of the temporal dimension. In this paper I consider several proposals for grounding the permissibility of such preferences and evaluate these in the light of the preferences we would have, and judge that we should have, in various time-travel scenarios. I argue that what we learn by considering these scenarios is that these preferences really have nothing to do with temporal structure. So if something grounds their permissibility, it is not temporal structure. (shrink)

While many aspects of cognition have been shown to be shared between humans and non-human animals, there remains controversy regarding whether the capacity to mentally time travel is a uniquely human one. In this paper, we argue that there are four ways of representing when some event happened: four kinds of temporal representation. Distinguishing these four kinds of temporal representation has five benefits. First, it puts us in a position to determine the particular benefits these distinct temporal representations (...) afford an organism. Second, it provides the conceptual resources to foster a discussion about which of these representations is necessary for an organism to count as having the capacity to mentally time travel. Third, it enables us to distinguish stricter from more liberal views of mental time travel that differ regarding which kind(s) of temporal representation is taken to be necessary for mental time travel. Fourth, it allows us to determine the benefits of taking a stricter or more liberal view of mental time travel. Finally, it ensures that disagreement about whether some species can mentally time travel is not merely the product of unrecognised disagreement about which temporal representation is necessary for mental time travel. We argue for a more liberal view, on the grounds that it allows us to view mental time travel as an evolutionarily continuous phenomenon, and to recognise that differences in the ways that organisms mentally time travel might reflect different temporal representations, or combinations thereof, that they employ. Our ultimate aim, however, is to create the conceptual framework for further discussion regarding what sorts of temporal representations are required for mental time travel. (shrink)

The Principle of Alternative Possibilities is the intuitive idea that someone is morally responsible for an action only if she could have done otherwise. Harry Frankfurt has famously presented putative counterexamples to this intuitive principle. In this paper, I formulate a simple version of the Principle of Alternative Possibilities that invokes a course-grained notion of actions. After warming up with a Frankfurt-Style Counterexample to this principle, I introduce a new kind of counterexample based on the possibility of time (...) class='Hi'>travel. At the end of the paper, I formulate a more sophisticated version of the Principle of Alternative Possibilities that invokes a certain fine grained notion of actions. I then explain how this new kind of counterexample can be augmented to show that even the more sophisticated principle is false. (shrink)

In this paper I defend two conclusions: that time travel journeys to the past are not undertaken freely and, more generally, that nobody is free between the earliest arrival time and the latest departure time of a time travel journey to the past. Time travel to the past destroys freedom on a global scale.

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.

I start off by relating the standard philosophical account of what time travel is to models of time travel that have recently been discussed by physicists. I then discuss some puzzles associated with time travel. I conclude that philosophers’ arguments against time travel are relevant when assessing the likelihood of the occurrence time travel in our world, and are relevant to the assessment whether time travel is physically possible.

The goal of this paper is to defend the general tenet that time travelers cannot change the past within B-theoretical models of time, independently of how many temporal dimensions there are. Baron Pacific Philosophical Quarterly, 98, 129–147 offered a strong argument intended to reach this general conclusion. However, his argument does not cover a peculiar case, i.e. a B-theoretical one-dimensional model of time that allows for the presence of internal times. Loss Pacific Philosophical Quarterly, 96, 1–11 used (...) the latter model to argue that time travelers can change the past within such model. We show a way to debunk Loss’s argument, so that the general tenet about the impossibility of changing the past within B-theoretical models is maintained. (shrink)

Time travel has been a staple of science fiction. With the advent of general relativity it has been entertained by serious physicists. But, especially in the philosophy literature, there have been arguments that time travel is inherently paradoxical. The most famous paradox is the grandfather paradox: you travel back in time and kill your grandfather, thereby preventing your own existence. To avoid inconsistency some circumstance will have to occur which makes you fail in this (...) attempt to kill your grandfather. Doesn't this require some implausible constraint on otherwise unrelated circumstances? We examine such worries in the context of modern physics. (shrink)

Existing puzzles about coinciding objects can be divided into two types, corresponding to the manner in which they bear upon the endurantism v. perdurantism debate. Puzzles of the first type, which involve temporary spatial co-location, can be solved simply by abandoning endurantism in favor of perdurantism, whereas those of the second type, which involve career-long spatial co-location, remain equally puzzling on both views. I show that the possibility of backward time travel would give rise to a new type (...) of puzzle. The new puzzles confront perdurantists and can be solved just by shifting to endurantism. (shrink)

In the present paper, I offer a new argument to show that presentism about time is incompatible with time travel. Time travel requires leaving the present, which, under presentism, contains all of reality. Therefore to leave the present moment is to leave reality entirely; i.e. to go out of existence. Presentist “time travel” is therefore best seen as a form of suicide, not as a mode of transportation. Eternalists about time do not (...) face the same difficulty, and time travel is compossible with eternalism. (shrink)

The present paper offers a philosophical discussion of phenomena which in the empirical literature have recently been subsumed under the concept of ‘mental time travel’. More precisely, the paper considers differences and similarities between two cases of ‘mental time travel’, recollective memories (‘R-memories’) of past events on the one hand, and sensory imaginations (‘S-imaginations’) of future events on the other. It develops and defends the claim that, because a subject who R-remembers a past event is experientially (...) aware of a past particular event, while a subject who S-imagines a future event could not possibly be experientially aware of a future particular event, R-memories of past events and S-imaginations of future events are ultimately mental occurrences of two different kinds. (shrink)

I argue that David Lewis’s philosophically dominant conception of time travel cannot straightforwardly handle what we might call cases of relativistic time travel—that is, the sort of time travel which could only plausibly occur in a relativistic setting. I evaluate whether or not the Lewisian account can be successfully adapted such that it would able to analyse potential cases of relativistic time travel satisfactorily while still being employable in the analysis of those (...) cases that make no mention of physics or the structure of spacetime. This is primarily an analytical and explanatory exercise, rather than a polemical one. (shrink)

This is a paper about time travel and what it teaches us about freedom. I argue that cases of time travel bring out an important difference between two ways of thinking about “the past”—either in terms of time itself, or in terms of causation. This ambiguity naturally transfers over to our talk about things like fixity, determinism, and incompatibilism. Moreover, certain cases of time travel suggest that our freedom is not constrained by the (...) temporal past _per se_, but by our own causal histories. This, in turn, raises a number of interesting questions about the formulation of incompatibilism and the broader debate over freedom. (shrink)

Patients with damage to the ventromedial prefrontal cortex (VMPFC) are often described as having impaired ability for planning and decision making despite retaining intact capacities for explicit reasoning. The somatic marker hypothesis is that the VMPFC associates implicitly represented affective information with explicit representations of actions or outcomes. Consequently, when the VMPFC is damaged explicit reasoning is no longer scaffolded by affective information, leading to characteristic deficits. These deficits are exemplified in performance on the Iowa Gambling Task (IGT) in which (...) subjects with VMPFC perform significantly worse than neurotypicals in a task which requires them learn from rewarding and punishing experience to make decisions. The somatic marker theory adopts a canonical theory of emotion, in which emotions function as part of a valencing system, to explain the role of affective processes. The first part of the paper argues against this canonical account. The second part provides a different account of the role of the role of the VMPFC in decision-making which does not depend on the canonical account of emotion. Together the first and second parts of the paper provide the basis for a different interpretation of results on the Iowa Gambling Task (IGT). In fact the IGT may be probing a deficit in what has been called mental time travel: the ability to access and use information from previous experience and imaginatively rehearse future experiences as part of the process of deliberation. (shrink)

Darwin and feminism: preliminary investigations into a possible alliance -- Darwin and the ontology of life -- The Nature of culture -- Law, justice, and the future -- The Time of violence: Derrida, deconstruction, and value -- Drucilla Cornell, identity, and the "Evolution" of Politics -- Philosophy, knowledge, and the future -- Deleuze, Bergson, and the virtual -- Merleau-Ponty, Bergson, and the question of ontology -- The thing -- Prosthetic objects -- Identity, sexual difference, and the future -- The (...) Time of thought -- The Force of sexual difference -- (Inhuman) forces: power, pleasure, and desire -- The future of female sexuality. (shrink)

The idea that episodic memory is a form of mental time travel has played an important role in the development of memory research in the last couple decades. Despite its growing importance in psychology, philosophers have only begun to develop an interest in philosophical questions pertaining to the relationship between memory and mental time travel. Thus, this paper proposes a more systematic discussion of the relationship between memory and mental time travel from the point (...) of view of philosophy. I start by discussing some of the motivations to take memory to be a form of mental time travel. I call the resulting view of memory the mental time travel view. I then proceed to consider important philosophical questions pertaining to memory and develop them in the context of the mental time travel view. I conclude by suggesting that the intersection of the philosophy of memory and research on mental time travel not only provides new perspectives to think about traditional philosophical questions, but also new questions that have not been explored before. (shrink)

ABSTRACTEpisodic memory is the ability to revisit events in one's personal past, to relive them as if one travelled back in mental time. It has widely been assumed that such an ability imposes a metaphysical requirement on selves. Buddhist philosophers, however, deny the requirement and therefore seek to provide accounts of episodic memory that are metaphysically parsimonious. The idea that the memory perspective is a centred field of experience whose phenomenal constituents are simulacra of an earlier field of experience, (...) yet attended to in a way that presents them as happening again, is, I suggest, a better one than that the memory perspective consists in taking as object-aspect the subject-aspect of the earlier experience, or the idea that it consists in labelling a representation of the earlier experience with an I-tag. (shrink)

In no possible world does a time traveler succeed in killing herearlier self before she ever enters a time machine. So if many,many time travelers went back in time trying to kill theirunprotected former selves, the time travelers would fail inmany strange, coincidental ways, slipping on bananapeels, killing the wrong victim, and so on. Such cases producedoubts about time travel. How could ``coincidences'' beguaranteed to happen? And wouldn't the certainty of coincidentalfailure imply that (...) time travelers are not free to killtheir earlier selves? But if so, what would inhibit theirfreedom? Despite initial appearances, these and other doubtsmay be answered: the possibility of time travel survives yetanother challenge. (shrink)

Thinking about time travel is an entertaining way to explore how to understand time and its location in the broad conceptual landscape that includes causation, fate, action, possibility, experience, and reality. It is uncontroversial that time travel towards the future exists, and time travel to the past is generally recognized as permitted by Einstein’s general theory of relativity, though no one knows yet whether nature truly allows it. Coherent time travel stories (...) have added flair to traditional debates over the metaphysical status of the past, the reality of temporal passage, and the existence of free will. Moreover, plausible models of time travel and time machines can be used to investigate the subtle relation between space-time structure and causality. -/- It surveys some philosophical issues concerning time travel and should serves as a quick introduction. It includes a new and improved way to define a time machine. (shrink)

The paper discusses radical constructivism about episodic memory as developed by Kourken Michaelian under the name of “simulationism”, a view that equates episodic memory with mental time travel. An alternative, direct realist view is defended, which implies disjunctivism about the appearance of remembering. While admitting the importance of mental time travel as an underlying cognitive mechanism in episodic memory, as well as the prima facie reasonableness of the simulationist’s critique of disjunctivism, I formulate three arguments in (...) defense of disjunctivism, which thus appears to be a feasible alternative to radical constructivism. (shrink)

We standardly evaluate counterfactuals and abilities in temporally asymmetric terms—by keeping the past fixed and holding the future open. Only future events depend counterfactually on what happens now. Past events do not. Conversely, past events are relevant to what abilities one has now in a way that future events are not. Lewis, Sider and others continue to evaluate counterfactuals and abilities in temporally asymmetric terms, even in cases of backwards time travel. I’ll argue that we need more temporally (...) neutral methods. The past shouldn’t always be held fixed, because backwards time travel requires backwards counterfactual dependence. Future events should sometimes be held fixed, because they’re in the causal history of the past, and agents have evidence of them independently of their decisions now. We need temporally neutral methods to maintain connections between causation, counterfactuals and evidence, and if counterfactuals are used to explain the temporal asymmetry of causation. (shrink)

Time travel has been a staple of science fiction. With the advent of general relativity it has been entertained by serious physicists. But, especially in the philosophy literature, there have been arguments that time travel is inherently paradoxical. The most famous paradox is the grandfather paradox: you travel back in time and kill your grandfather, thereby preventing your own existence. To avoid inconsistency some circumstance will have to occur which makes you fail in this (...) attempt to kill your grandfather. Doesn't this require some implausible constraint on otherwise unrelated circumstances? We examine such worries in the context of modern physics. (shrink)

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)

Mental time travel research emphasizes the connection between past and future thinking, whereas autobiographical memory research emphasizes the interrelationship of self and memory. This study explored the relationship between self and memory when thinking about both past and future events. Participants reported events from the near and distant past and future, for themselves, a close friend, or an acquaintance. Past events were rated higher in phenomenological quality than future events, and near self events were rated higher in quality (...) than those about friends. Although future events were more positive than past events, only valence ratings for self and close friend showed a linear increase in positivity from distant past to future. Content analysis showed that this increase in positivity could not be ascribed to choosing events from the cultural life script. These findings provide evidence for the role of personal goals in imagining the future. (shrink)

Notoriously, the Einstein equations of general relativity have solutions in which closed timelike curves occur. On these curves time loops back onto itself, which has exotic consequences: for example, traveling back into one's own past becomes possible. However, in order to make time travel stories consistent constraints have to be satisfied, which prevents seemingly ordinary and plausible processes from occurring. This, and several other "unphysical" features, have motivated many authors to exclude solutions with CTCs from consideration, e.g. (...) by conjecturing a chronology protection law. In this contribution we shall investigate the nature of one particular class of exotic consequences of CTCs, namely those involving unexpected cases of indeterminism or determinism. Indeterminism arises even against the backdrop of the usual deterministic physical theories when CTCs do not cross spacelike hypersurfaces outside of a limited CTC-region|such hypersurfaces fail to be Cauchy surfaces. We shall compare this CTC-indeterminism with four other types of indeterminism that have been discussed in the philosophy of physics literature: quantum indeterminism, the indeterminism of the hole argument, non-uniqueness of solutions of differential equations and lack of predictability due to insuffcient data. By contrast, a certain kind of determinism appears to arise when an indeterministic theory is applied on a CTC: things cannot be different from what they already were. Again we shall make comparisons, this time with other cases of determination in physics. We shall argue that on further consideration both this indeterminism and determinism on CTCs turn out to possess analogues in other, familiar areas of physics. CTC- indeterminism is close to the epistemological indeterminism we know from statistical physics, while the "fixedness" typical of CTC-determinism is pervasive in physics. CTC- determinism and CTC-indeterminism therefore do not provide incontrovertible grounds for rejecting CTCs as conceptually inadmissible. (shrink)

Are humans alone in their ability to reminisce about the past and imagine the future? Recent evidence suggests that food-storing birds (scrub jays) have access to information about what they have stored where and when. This has raised the possibility of mental time travel (MTT) in animals and sparked similar research with other species. Here we caution that such data do not provide convincing evidence for MTT. Examination of characteristics of human MTT (e.g. non-verbal declaration, generativity, developmental prerequisites) (...) points to other avenues as to how a case for animal MTT could be made. In light of the current lack of evidence, however, we maintain that MTT is a uniquely human characteristic. (shrink)

According to the prevailing sentiment, changing the past is logically impossible. The prevailing sentiment is wrong. In this paper, I argue that the claim that changing the past entails a contradiction ultimately rests upon an empirical assumption, and so the conclusion that changing the past is logically impossible is to be resisted. I then present and discuss a model of time which drops the empirical assumption and coherently models changing the past. Finally, I defend the model, and changing the (...) past, against objections. (shrink)

It has sometimes been suggested that backwards time travel always incurs causal loops. I show that this is mistaken, by describing worlds where backwards time travel occurs and yet no causal loops occur. Arguments that backwards time travel can occur without causal loops have been given before in the literature, but I show that those arguments are unconvincing.

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)

There is an extensive literature on time travel in both philosophy and physics. Part of the great interest of the topic stems from the fact that reasons have been given both for thinking that time travel is physically possible—and for thinking that it is logically impossible! This entry deals primarily with philosophical issues; issues related to the physics of time travel are covered in the separate entries on time travel and modern physics (...) and time machines. We begin with the definitional question: what is time travel? We then turn to the major objection to the possibility of backwards time travel: the Grandfather paradox. Next, issues concerning causation are discussed—and then, issues in the metaphysics of time and change. We end with a discussion of the question why, if backwards time travel will ever occur, we have not been visited by time travellers from the future. (shrink)

The first section of this article focuses on the treatment of “time travel” in science-fiction literature and film as presented in the secondary literature in that field. The first anthology I will consider has a metaphysical focus, including (a) relating the time travel of science fiction to the banal time travel of all living beings, as we move inexorably toward the future; and (b) arguing for the filmstrip as the ultimate metaphor for time. (...) The second anthology I will consider has a more political focus, arguing that the “special effects” form of science-fiction films, rather than the visual or narrative content of science-fiction-films, is truly imaginative and futural. The second section of this article ties together a variety of concepts and insights between time-travel cinema and Deleuze’s Cinema 1, suggesting (among other things) that (c) time-traveling characters in cinema function as a redoubled phenomenon of the “mobile sections” of Bergsonian duration (in reference to Henri Bergson), and (d) time-travel cinema vividly illustrates the imagistic nature of the entire world. (shrink)

I wish to discuss a supposed implication of one sort of time travel. The sort of time travel is time travel into one’s past along a closed timelike curve. The implication is that in spacetimes with CTCs there can be no temporal passage or “flow” of time. I will argue that the implication does not hold.

Introduction: Time travel and the mechanics of narrative -- Macrological fictions: evolutionary utopia and time travel (1887-1905) -- Historical interval I: the first time travel story -- Relativity, psychology, paradox: Wertenbaker to Heinlein (1923-1941) -- Historical interval II: three phases of time travel--the time machine -- The big time: multiple worlds, narrative viewpoint, and superspace -- Paradox and paratext: picturing narrative theory -- Theoretical interval: the primacy of the visual in (...) time travel narrative -- Viewpoint-over-histories: narrative conservation in Star Trek -- Oedipus multiplex, or, the subject as a time travel film: Back to the future -- Conclusion: The last time travel story. (shrink)

A recent account of presentist time travel involves a causal relation between events at two different and discontiguous times, and presentists cannot have such causal relations because presentism rules out the existence of at least one of the two relata in such a relation due to it being non-present. Additionally, presentists cannot have parodies of such causal relations for use in time travel stories because parodies are subject, at least, to the same limitations as the things (...) being parodied. So, the presentist has not successfully given an internally consistent account of presentist time travel. (shrink)

Time travel is a solved problem. Einstein showed that if you travel in a spaceship for months at speeds close to the speed of light, you can return to earth centuries in the future.

Episodic memory (memories of the personal past) and prospecting the future (anticipating events) are often described as mental time travel (MTT). While most use this description metaphorically, we argue that episodic memory may allow for MTT in at least some robust sense. While episodic memory experiences may not allow us to literally travel through time, they do afford genuine awareness of past-perceived events. This is in contrast to an alternative view on which episodic memory experiences present (...) past-perceived events as mere intentional contents. Hence, episodic memory is a way of coming into experiential contact with, or being again aware of, what happened in the past. We argue that episodic memory experiences depend on a causal-informational link with the past events being remembered, and that, assuming direct realism about episodic memory experiences, this link suffices for genuine awareness. Since there is no such link in future prospection, a similar argument cannot be used to show that it also affords genuine awareness of future events. Constructivist views of memory might challenge the idea of memory as genuine awareness of remembered events. We explain how our view is consistent with both constructivist and anti-causalist conceptions of memory. There is still room for an interpretation of episodic memory as enabling genuine awareness of past events, even if it involves reconstruction. (shrink)

The paper first tries to explain how the possibility of "time travel" arises in the Godel universe. It then goes on to discuss a technical problem conerning minimal acceleration requirements for time travel. A theorem is stated and a conjecture posed. If the latter is correct, time travel can be ruled out as a practical possibility in the Godel universe.

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)