The Multiverse Thesis is a proposed solution to the Grandfather Paradox. It is popular and well promulgated, found in fiction, philosophy and (most importantly) physics. I first offer a short explanation on behalf of its advocates as to why it qualifies as a theory of time travel (as opposed to mere 'universe hopping'). Then I argue that the thesis nevertheless has an unwelcome consequence: that extended objects cannot travel in time. Whilst this does not demonstrate that the Multiverse Thesis is (...) false, the consequence should give pause for concern. Even if it does not lead one to reject the thesis, I briefly detail some reasons to think it is interesting nonetheless. (shrink)

One reading of the Doctrine of Original Sin has it that we are guilty of a sin committed by Adam, thousands of years ago. Fission theorists account for this by saying that Adam fissioned after he sinned and that each of us is one of his ‘fission successors’. This paper recaps the current discussion in the literature about this theory, arguing that the proposed version does not work for reasons already raised by Rea and Hudson. I then introduce a new (...) version of fission theory that avoids the Rea-Hudson objection. (shrink)

The notion of multiple location plays an important role in the characterization of endurantism. Several authors have recently offered cases intended to demonstrate the incoherence of multiple location. I argue that these cases do not succeed in making multiple location problematic. Along the way, several crucial issues about multiple location and its use by endurantists are clarified.

I sketch a new constraint on chance, which connects chance ascriptions closely with ascriptions of ability, and more specifically with 'CAN'-claims. This connection between chance and ability has some claim to be a platitude; moreover, it exposes the debate over deterministic chance to the extensive literature on (in)compatibilism about free will. The upshot is that a prima facie case for the tenability of deterministic chance can be made. But the main thrust of the paper is to draw attention to the (...) connection between the truth conditions of sentences involving 'CAN' and 'CHANCE', and argue for the context sensitivity of each term. Awareness of this context sensitivity has consequences for the evaluation of particular philosophical arguments for (in) compatibilism when they are presented in particular contexts. (shrink)

This paper examines various philosophical arguments to do with time travel. It argues that time travel has not been shown to be logically impossible. It then considers whether time travel would give rise to improbable strings of coincidences, or closed causal loops. Finally, it considers whether we could ever be justified in believing someone who claimed to be a time traveller, or whether we would always be more justified in believing that the claimant was either deluded or trying to deceive (...) us. For this last issue the Terry Gilliam film ‘Twelve Monkeys’ is used as an example. (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)

A recent paper from Brun et al. has argued that access to a closed timelike curve would allow for the possibility of perfectly distinguishing nonorthogonal quantum states. This result can be used to develop a protocol for instantaneous nonlocal signaling. Several commenters have argued that nonlocal signaling must fail in this and in similar cases, often citing consistency with relativity as the justification. I argue that this objection fails to rule out nonlocal signaling in the presence of a CTC. I (...) argue that the reason these authors are motivated to exclude the prediction of nonlocal signaling is because the No Signaling principle is considered to a fundamental part of the formulation of the quantum information approach. I draw out the relationship between nonlocal signaling, quantum information, and relativity, and argue that the principle theory formulation of quantum mechanics, which is at the foundation of the quantum information approach, is in tension with foundational assumptions of Deutsch’s D-CTC model, on which this protocol is based. (shrink)

I argue that Deutsch’s model for the behavior of systems traveling around closed timelike curves relies implicitly on a substantive metaphysical assumption. Deutsch is employing a version of quantum theory with a significantly supplemented ontology of parallel existent worlds, which differ in kind from the many worlds of the Everett interpretation. Standard Everett does not support the existence of multiple identical copies of the world, which the D-CTC model requires. This has been obscured because he often refers to the branching (...) structure of Everett as a “multiverse”, and describes quantum interference by reference to parallel interacting definite worlds. But he admits that this is only an approximation to Everett. The D-CTC model, however, relies crucially on the existence of a multiverse of parallel interacting worlds. Since his model is supplemented by structures that go significantly beyond quantum theory, and play an ineliminable role in its predictions and explanations, it does not represent a quantum solution to the paradoxes of time travel. (shrink)

It is claimed that unacceptable constraints on initial data are imposed by certain responses to paradoxes that threaten time travel, closed timelike curves (CTCs) and other backwards causation hypotheses. In this paper I argue against the following claims: to say “contradictions are impossible so something must prevent the paradox” commits in general to constraints on initial data, that for fixed point dynamics so-called grey state solutions explain why contradictions do not arise, and the latter have been proved to avoid constraints (...) on initial data. †To contact the author, please write to: Philosophy, University of Queensland, Brisbane, Queensland 4072, Australia; e-mail: [email protected]. (shrink)

There is a long tradition of preferring local theories to ones that posit lawful or causal influence at a spacetime distance. In this paper, we argue against this preference. We argue that nonlocality is scientifically unobjectionable and that nonlocal theories can be known. Scientists can gather evidence for them and confirm them in much the same way that they do for local theories. We think these observations point to a deeper constraint on scientific theorizing and experimentation: the (quasi‐) isolation of (...) causal or lawful influence. We argue that this requirement ought to replace the locality desideratum in science. We then explore the possibility that the order of explanation has been reversed: perhaps it is isolatable influence that determines what counts as local in the first place. (shrink)

If a person, A, branches into B and C, then it is widely held that B and C are not identical to one another. Many think that this is because B and C have contradictory properties at the same time. In this paper, I show why this explanation cannot be right. I argue that contradictory properties at times are not necessary for non-identity between descendants, and that contradictory properties at times are not sufficient for non-identity. I also argue that the (...) standard explanation cannot be salvaged by a shift to personal time. Appeals to a lack of continuity, or to the absence of unity of consciousness likewise fail. Rather, B and C are non-identical simply because A branched into B and C. Why branching should be problematic for personal identity remains a deep puzzle though I offer some tentative suggestions. (shrink)

I reconcile the spatiotemporal location of repeatable artworks and impure sets with the non-location of natural numbers despite all three being varieties of abstract objects. This is possible because, while the identity conditions for all three can be given by abstraction principles, in the former two cases spatiotemporal location is a congruence for the equivalence relation featuring in the relevant principle, whereas in the latter it is not. I then generalize this to other ‘physical’ properties like shape, mass, and causal (...) powers. (shrink)

Here I defend the compatibility of presentism and time travel against a few objections. Keller and Nelson argue that, if presentism is at all plausible, presentism and time travel are as compatible as eternalism and time travel. But Miller and Sider are not convinced. I reply that for their concerns to have merit, Miller and Sider must assume presentists are committed to positions they need not be; I explain why presentists are not so committed and, in the process, defend Keller (...) and Nelson’s position that there is no roadblock to presentist time travel that does not also apply to eternalist time travel. (shrink)

The claim that we are subjects of experience, i.e. beings whose nature is intimately bound up with consciousness, is in many ways a plausible one. There is, however, more than one way of developing a metaphysical account of the nature of subjects. The view that subjects are essentially conscious has the unfortunate consequence that subjects cannot survive periods of unconsciousness. A more appealing alternative is to hold that subjects are beings with the capacity to be conscious, a capacity which need (...) not always be exercised. But this view can itself be developed in more than one way. The option I defend here is that subjects are nothing more than capacities for consciousness, a view I call the. Although the C-theory supplies us with a potentially appealing account of the nature of subjects, there are challenges to be overcome. Olson has argued that identifying ourselves with what are, in effect, parts of human organisms leads to a variety of intolerable problems. I suggest that these problems are by no means insuperable. Bayne and Johnston have argued that identifying subjects with experience-producing systems is confronted with a different difficulty. What if these systems can produce multiple streams of consciousness at once. Whatever else they may be, aren't subjects the kind of thing that can have just one stream of consciousness at a time? In response I argue that this is true in one sense, but not in another. Once this is appreciated, the notion that a subject could have several streams of consciousness at once no longer seems absurd, or impossible. (shrink)

Causal finitism, the view that the causal history of any event must be finite, has garnered much philosophical interest recently—especially because of its applicability to the Kalām cosmological argument. The most prominent argument for causal finitism is the Grim Reaper argument, which attempts to show that, if infinite causal histories are possible, then other paradoxical states of affairs must also be possible. However, this style of argument has been criticized on the grounds of (i) relying on controversial modal principles, and (...) (ii) providing a false diagnosis of the paradoxes involved. In this paper, I develop a new kind of Grim Reaper argument immune to these criticisms. I show that, by using insights from the literature on time travel, causal finitists should instead argue that infinite causal histories are problematically inexplicable, as they entail the possibility of unexplained foiling mechanisms. The fruits of this paper are that (i) a novel supporting argument for the Kalām is developed, and (ii) along the way of building this argument, it is shown that the literatures on time travel and causal finitism are deeply and intimately connected. (shrink)

It is widely thought that, to be morally responsible for some action or omission, an agent must have had, at the very least, the general ability to do otherwise. As we argue, however, there are counterexamples to the claim that moral responsibility requires the general ability to do otherwise. We present several cases in which agents lack the general ability to do otherwise and yet are intuitively morally responsible for what they do, and we argue that such cases raise problems (...) for various kinds of accounts of moral responsibility. We suggest two alternative approaches to thinking about the connection between moral responsibility and abilities to do otherwise, one of which denies that there is any ability-to-do-otherwise requirement on moral responsibility and the other of which requires only an opportunity to do otherwise. We also argue that a general-ability-to-do-otherwise requirement not only faces counterexamples but also lacks positive motivation. (shrink)

This paper examines the stability of objective chance. I defend the stable chance thesis : that in any given possible world, any pair of intrinsic duplicate physical setups with the same chances of being subject to the same external influences must yield the same chances. I argue that SCT compares favourably to rivals in the literature. I then consider a challenge to SCT involving time travel and causal loops. I argue that SCT survives this challenge, but that such cases expose (...) chance as less stable than we might unreflectively have thought. In particular, the chances associated with a physical setup are sensitive to the way that this setup is embedded in a wider causal structure. (shrink)

I argue that the past can be objectively chancy in cases of backwards causation, and defend a view of chance that allows for this. Using a case, I argue against the popular temporal view of chance, according to which chances are defined relative to times, and all chancy events must lie in the future. I then state and defend the causal view of chance, according to which chances are defined relative to causal histories, and all chancy events must lie causally (...) downstream. The causal view replicates the intuitively correct results of the temporal view in cases of ordinary forwards causation, while correctly handling cases of backwards causation. I conclude that objective chance is more closely related to the direction of causation than it is to the direction of time. (shrink)

Marianne Dashwood was well able to imagine circumstances both favourable and unfavourable to her. But for all her romantic sensibility she was not able to imagine these things from anything other than her own point of view. ‘She expected from other people the same opinions and feelings as her own, and she judged of their motives by the immediate effect of their actions on herself.’ Unlike her sister, she could not see how the ill-crafted attentions of Mrs. Jennings could derive (...) from a good nature. And when Elinor had to explain her troubles with Edward Ferrars, she knew that Marianne would feel it as a reminder of her own relations to Willoughby, judging Edward's behaviour as equivalent to that of Willoughby himself. Without the capacity to shift her point of view, Marianne can get no ironic distance from herself; she cannot see the unrealism of her later determination ‘to live solely for my family’. (shrink)

The possibility of multi-location—of one entity having more than one exact location—is required by several metaphysical theories such as the immanentist theory of universals and three-dimensionalism about persistence. One of the most pressing challenges for multi-location theorists is that of making sense of exact location—in that extant definitions of exact location entail a principle called ‘functionality’, according to which nothing can have more than one exact location. Recently in a number of promising papers, Antony Eagle has proposed and defended a (...) definition of exact location in terms of weak location that does not entail functionality. This paper provides the first thorough assessment of Eagle’s proposal. In particular, we argue that it cannot account for the location of immanent universals, the multi-location of mereologically changing three-dimensional objects, the multi-location of mereologically complex objects, and that it makes extended simples impossible. (shrink)

Kenneth Silver has recently argued that backwards causation is common in the context of social institutions. I consider this claim in detail and conclude that backwards causation is not the most plausible interpretation of what is going on in the cases Silver considers. Nonetheless, I show that these cases can teach us some interesting lessons about institutional facts. In particular, I argue that in order to avoid contradiction due to conflicting declarations in these cases, we must conclude that the properties (...) involved in institutional facts are relational properties. (shrink)

The philosophy of time travel is a sub-field of metaphysics – the study of what there is and what things are like – that considers questions about the possibility of time travel and what a world in which time travel is possible looks like. These questions range from whether time travel is actually possible, to how time travellers can act in the past or future. This thesis delves into a particularly interesting, yet historically undertreated theme: the abilities of time travellers (...) and relatedly their freedom as well. The abilities and freedom of time travellers has been the source of a lot of recent discussion with some polarising views. The minority (which includes Lewis (1976), but also Ted Sider (2002)) argue for the affirmative – that time travellers are free and have the same (or perhaps more) abilities as non-time travellers. The majority (which includes Kadri Vihvelin (1996), Michael Rea (2005), Stephanie Rennick (2015), Alison Fernandes (2020), amongst others) argue for the negative, that time travellers do not have exactly the same freedoms and abilities as non-time travellers. I think that it is a mistake to be so pessimistic about the abilities and freedom of time travellers. I treat concerns about the freedom of time travellers and concerns about the abilities of time travellers as two sides of the same coin. Therefore, in what follows, I argue for two related conclusions. First, I argue that time travellers have all sorts of abilities. Second, I argue that time travellers are just as free as non-time travellers. In arguing for these conclusions, I first produce a novel analysis of ability which reveals important details about how abilities track inputs rather than outputs. Second, I use this new analysis of ability to present a new compatibilist account of free will. If I am right in arguing positively for the abilities and freedoms of time travellers, then this has large implications for both the current time travel discourse and the general debate surrounding freedom. Significantly, I am arguing against some prominent views about time travel and in suggesting that these views are mistaken, I am presenting new ideas about ability and freedom: specifically, that time travellers have the ability and are free to do impossible things. (shrink)

I argue that the theory of moral responsibility defended by John Martin Fischer and Mark Ravizza is incompatible with the metaphysical possibility of time travel.

David Lewis defends the following "non-circular definition of personhood": "something is a continuant person if and only if it is a maximal R-interrelated aggregate of person-stages. That is: if and only if it is an aggregate of person-stages, each of which is R-related to all the rest (and to itself), and it is a proper part of no other such aggregate." I give a counterexample, involving a person who is a part of another, much larger person, with a separate mental (...) life. I then offer an easy repair, which preserves the virtues of Lewis's definition without introducing any new vices. (shrink)

This paper examines recent attempts to revive a classic compatibilist position on free will, according to which having an ability to perform a certain action is having a certain disposition. Since having unmanifested dispositions is compatible with determinism, having unexercised abilities to act, it is held, is likewise compatible. Here it is argued that although there is a kind of capacity to act possession of which is a matter of having a disposition, the new dispositionalism leaves unresolved the main points (...) of dispute concerning free will. (shrink)

The possibility of continuous backwards time travel—time travel for which the traveler follows a continuous path through space between departure and arrival—gives rise to the double-occupancy problem. The trouble is that the time traveler seems bound to have to travel through his or her younger self as the trip begins. Dowe and Le Poidevin agree that this problem is solved by putting the traveler in motion for a gradual trip to the past. Le Poidevin goes on to argue, however, that (...) the gradual trip gives rise to the Cheshire cat problem, a concern about whether the traveler survives the gradual trip. We address the Cheshire cat problem by proposing and considering new continuity constraints on identity over time. Along the way, we come upon an endurantist conception of temporal parts. (shrink)

Several recent arguments purport to show that omnipotence is incompatible with the possession of various necessary properties. These arguments appeal to one of two plausible but false principles about the nature of power: that if it is metaphysically impossible for a being to actualize a state of affairs, then that being does not have the power to actualize that state of affairs, or that if it is impossible given some contingent facts about the world that a being actualize a state (...) of affairs, then that being does not have the power to actualize that state of affairs. I pose several problems for both principles, thereby undermining the plausibility of these arguments. I then consider the implications of rejecting these principles for related principles in the free will debate. These implications suggest important differences between having the power to bring about a state of affairs, having a choice about whether it obtains, and being able to bring it about. (shrink)

Ted Sider aptly and concisely states the self-visitation paradox thus: 'Suppose I travel back in time and stand in a room with my sitting 10-year-old self. I seem to be both sitting and standing, but how can that be?' (2001, 101). I will explore a relativist resolution of this paradox offered by, or on behalf of, endurantists.1 It maintains that the sitting and the standing are relative to the personal time or proper time of the time traveler and is intended (...) to yield the result that Ted is sitting at a certain initial personal/proper time but is not standing relative to that time. Similarly, it is also supposed to yield that Ted is standing relative to a later personal/proper time, but not sitting relative to that .. (shrink)

Knowledge, like other things of value, can be faked. According to Hawley (2011), know-how is harder to fake than knowledge-that, given that merely apparent propositional knowledge is in general more resilient to our attempts at successful detection than are corresponding attempts to fake know-how. While Hawley’s reasoning for a kind of detection resilience asymmetry between know-how and know-that looks initially plausible, it should ultimately be resisted. In showing why, we outline different ways in which know-how can be faked even when (...) a given performance is successful; and in doing so, we distinguish how know-how can be faked (no less than know-that) via upstream and downstream indicators of its presence, and within each of these categories, we’ll distinguish (in connection with detection resilience) both faking symptoms and (various kinds of) criteria. The unappreciated resilience of faked knowledge-how to successful detection highlights a largely overlooked dimension of social-epistemic risk – risk we face not just in our capacity as recipients of testimony, but in our capacity as both (would-be) apprentices and clients of knowledge-how. (shrink)

_If you were free in doing something and morally responsible for it, you could have done otherwise. That_ _has seemed a pretty firm proposition among the old, new, clear, unclear and other propositions in the_ _philosophical discussion of freedom and determinism. If you were free in what you did, there was an_ _alternative. It is also at least natural to think that if determinism is true, you can never do otherwise than_ _you do. G. E. Moore, that Cambridge reasoner in (...) whose shadow Wittgenstein ought to be standing,_ _considered the matter. He pointed out that even if determinism is true, there remains a sense in which you_ _can still do otherwise than you do: you will do otherwise if you so choose. That, on reflection, is consistent_ _with determinism. The doctrine of the compatibility of freedom and determinism is saved. Joseph Keim_ _Campbell, strong philosopher at Washington State University, provides the latest thinking on this seemingly_ _unavoidable dispute. You do not have to agree that either compatibilism or incompatibilism must be true in_ _order to appreciate the carefulness of his reasoning in this piece of ongoing American philosophy. It_ _requires and repays attention._. (shrink)

Must space be a unity? This question, which exercised Aristotle, Descartes and Kant, is a specific instance of a more general one; namely, can the topology of physical space change with time? In this paper we show how the discussion of the unity of space has been altered but survives in contemporary research in theoretical physics. With a pedagogical review of the role played by the Euler characteristic in the mathematics of relativistic spacetimes, we explain how classical general relativity (modulo (...) considerations about energy conditions) allows virtually unrestrained spatial topology change in four dimensions. We also survey the situation in many other dimensions of interest. However, topology change comes with a cost: a famous theorem by Robert Geroch shows that, for many interesting types of such change, transitions of spatial topology imply the existence of closed timelike curves or temporal non-orientability. Ways of living with this theorem and of evading it are discussed. (shrink)

Roman Catholic and Eastern Orthodox theologians claim that the unique event of Christ’s sacrifice on Calvary is present in Eucharistic liturgies. A popular explanatory strategy for this miraculous presence suggests that due to its supernatural character the Eucharist “conquers time,” transcends its boundaries, and allows for temporal coincidence of two chronologically distant events. I discuss the four main approaches within this strategy that can be discovered in contemporary theological writings. The first approach implies a time travel of the Calvary event. (...) The second suggests the time travel of Eucharistic participants. The third eliminates the chronological distance by relocating one of the events into a timeless reality. The fourth assumes multilocation of the event across time. I argue that each of these approaches is untenable on philosophical or theological grounds. (shrink)

I discuss the idea of relativistic causality, i.e., the requirement that causal processes or signals can propagate only within the light-cone. After briefly locating this requirement in the philosophy of causation, my main aim is to draw philosophers' attention to the fact that it is subtle, indeed problematic, in relativistic quantum physics: there are scenarios in which it seems to fail. I set aside two such scenarios, which are familiar to philosophers of physics: the pilot-wave approach, and the Newton-Wigner representation. (...) I instead stress two unfamiliar scenarios: the Drummond-Hathrell and Scharnhorst effects. These effects also illustrate a general moral in the philosophy of geometry: that the mathematical structures, especially the metric tensor, that represent geometry get their geometric significance by dint of detailed physical arguments. (shrink)

Whether we’re reading H.G. Wells, Robert Heinlein, Ray Bradbury, or Kurt Vonnegut, time travel is a wonderful narrative trick, freeing a story from the normal ‘one damn thing after another’ progression of time. But many philosophers claim it can never be more than that because backwards causation in general, and time travel in particular, are logically impossible.In this paper I examine one type of argument commonly given for this disappointing conclusion: the time travel paradoxes. Happily for science fiction fans, these (...) arguments fall far short of showing what they are intended to show. Why they fail can be better understood in the light of an analogy between these arguments and some arguments libertarians offer against determinism. (shrink)

Braun (Linguistics & Philosophy 35, 461–489, 2012) argued for a non- relativist, invariantist theory of ‘might’. Yanovich (Linguistics & Philosophy, 2013) argues that Braun’s theory is inconsistent with certain facts concerning diachronic meaning changes in ‘might’, ‘can’, and ‘may’. This paper replies to Yanovich’s objection.

This paper is about the principle that success entails ability, which I call Success. I argue the status of Success is highly puzzling: when we focus on past instances of actually successful action, Success is very compelling; but it is in tension with the idea that true ability claims require an action be in the agent's control. I make the above tension precise by considering the logic of ability. I argue Success is appealing because it is classically equivalent to two (...) genuinely valid inferences, which I call Past Success and Can't-Entails-Won't; but also that Success itself has counterexamples. I show how to invalidate Success while validating Past Success and Can't-Entails-Won't by connecting the meaning of ‘can’ to facts about what is settled or open. I define an operator W with features attributed to ‘will’ in the literature on future contingents. I then give a conditional analysis of ability ascriptions stated with W-conditionals, where "S can A" says, roughly, there’s some action available to S such that if S does it, then W(S A). I show this semantics invalidates Success while still explaining its appeal. (shrink)

This paper divides the sophisms and paradoxes put forth by Chinese thinkers of the pre-Qin period of China into six groups: paradoxes of motion and infinity, paradoxes of class membership, semantic paradoxes, epistemic paradoxes, paradoxes of relativization, other logical contradictions. It focuses on the comparison between the Chinese items and the counterparts of ancient Greek and even of contemporary Western philosophy, and concludes that there turn out to be many similar elements of philosophy and logic at the beginnings of Chinese (...) and Greek civilizations. (shrink)

Recently in Analysis, Ned Markosian (2019) has argued that a popular theory in the metaphysics of time—the Spacetime Thesis—falsely predicts that a normal musical performance is just as aesthetically valuable if it is rotated “sideways,” that is, if it is made to occur all at once. However, this argument falsely assumes that changing how something is oriented in space, and changing its duration in time, are analogous. That said, assuming they were analogous, Markosian’s argument is still unsuccessful. For the analogy (...) on which Markosian’s argument depends entails that if one can experience sideways music as it was originally, then one can prove that sideways music is just as aesthetically valuable. (shrink)

Metaphysicians of a certain stripe are almost unanimously of the view that grounding is necessarily irreflexive, asymmetric, transitive, and well-founded. They deny the possibility of circles of ground and, therewith, the possibility of species of metaphysical coherentism. But what's so bad about circles of ground? One problem for coherentism might be that it ushers in anti-foundationalism: grounding loops give rise to infinite regresses. And this is bad because infinite grounding regresses are vicious. This article argues that circles of ground do (...) not necessarily give rise to infinite regresses, and where they do, those regresses are not necessarily vicious. (shrink)

This paper suggests that time travelling scenarios commonly depicted in science fiction introduce problems and dangers for the time traveller. If time travel takes time, then time travellers risk collision with past objects, relocation to distant parts of the universe, and time travel-specific injuries. I propose several models of time travel that avoid the dangers and risks of time travel taking time, and that introduce new questions about the relationship between time travel and spatial location.

Dummett and others have failed to show that an effect can precede its cause. Dummett claimed that 'backwards causation' is unproblematic in agentless worlds, and tried to show under what conditions it is rational to believe that even backwards agent-causation occurs. Relying on considerations originating in discussions of special relativity, I show that the latter conditions actually support the view that backwards agent-causation is impossible. I next show that in Dummett's agentless worlds explanation does not necessitate backwards causation. I then (...) show why even relative backwards causation is impossible in his and Tooley's scenarios of parallel processes in which causes apparently act in opposite temporal directions. We thus have good reasons for thinking that backwards causation is impossible. (shrink)

Does mere passage of time have causal powers ? Are properties like "being n days past" causally efficient ? A pervasive intuition among metaphysicians seems to be that they don't. Events and/or objects change, and they cause or are caused by other events and/or objects; but one does not see how just the mere passage of time could cause any difference in the world. In this paper, I shall discuss a case where it seems that mere passage of time does (...) have causal powers : Sydney Shoemaker's (1969) possible world where temporal vacua (allegedly) take place. I shall argue that Shoemaker's thought-experiment doesn't really aim at teaching us that there can be time without change, but rather that if such a scenario is plausible at all (as I think it is) it provides us with good reasons to think that mere passage of time can be directly causally efficient. (shrink)

Metaphysical theories are often counter-intuitive. But they also often are strongly supported and motivated by intuitions. One way or another, the link between intuitions and metaphysics is a strong and important one, and there is hardly any metaphysical discussion where intuitions do not play a crucial role. In this article, I will be interested in a particular kind of such intuitions, namely those that come, at least partly, from experience. There seems to be a route from experience to metaphysics, and (...) this is the core of my interest here. In order to better understand such ‘arguments from experience’ and the kind of relationship there is between this type of intuitions and metaphysical theories, I shall examine four particular cases where a kind of experience-based intuition seems to motivate or support a metaphysical theory. At the end of the day, I shall argue that this route is a treacherous one, and that in all of the four cases I shall concentrate on, phenomenological considerations are in fact orthogonal to the allegedly ‘corresponding’ metaphysical claims. An anti-realist view of metaphysics will emerge. (shrink)