Analytic Philosophy, Volume 62, Issue 3, Page 275-294, September 2021.

How should rational beliefs change over time? The standard Bayesian answer is: by conditionalization (a.k.a. Bayes’ Rule). But conditionalization is not an adequate rule for updating beliefs in “centred” propositions whose truth-value may itself change over time. In response, some have suggested that the objects of belief must be uncentred; others have suggested that beliefs in centred propositions are not subject to diachronic norms. Iargue that these views do not offer a satisfactory account of self-locating beliefs and their dynamics. A (...) third response is to replace conditionalization by a new norm that can deal with centred propositions. I critically survey anumber of new norms that have been proposed, and defend one particular approach. (shrink)

The compatibilism debate revolves around the question whether moral responsibility and free will are compatible with determinism. Prima facie, this seems to be a substantial issue. But according to the triviality objection, the disagreement is merely verbal: compatibilists and incompatibilists, it is maintained, are talking past each other, since they use the terms “free will” and “moral responsibility” in different senses. In this paper I argue, first, that the triviality objection is indeed a formidable one and that the standard replies (...) to it are unconvincing. This, however, does not mean that the objection succeeds. Starting with the debate about moral responsibility, I attempt to show that there is an account of moral responsibility which enables us to defend the compatibilism debate against the charge of triviality—namely, the normative conception of moral responsibility. If “moral responsibility” is defined in normative terms, then we cannot distinguish between a compatibilist and an incompatibilist sense of “moral responsibility”, because such a disambiguation would be inconsistent with the essential action-guiding force of normative expressions. Finally, I examine how the normative conception of moral responsibility can help us to defend the free will debate against the triviality objection and draw some general conclusions. (shrink)

A famous puzzle called “Grandmother Paradox” is used to argue against the feasibility of traveling backward in time because of the logical and nomological problems such travel involves, and not only because we don’t have the technology to make it reality. The same kind of problems would be encountered in leaping forward in time and then returning to the time of departure. We argue that a similar family of problems also arise in our having foreknowledge of the future without making (...) any time travel. We point to the mysterious consequences of having access to a being, say a machine or a psychic, that can have infallible knowledge of the future and conveys this foreknowledge to human beings truthfully, without any lies or distortions. The cause of these mysterious consequences is the fact that such machines or psychics will raise logical and nomological complications reminiscent of the ones we encounter in time travel scenarios, and that is a strong reason why infallible foretellers cannot exist. We conclude that we can have foreknowledge of the future, in principle, only within certain narrow limits, if at all. (shrink)

Moore’s Mechanical Choices is ripe with interesting ideas. Here I’ll focus on a particularly intriguing one that intersects with some aspects of my own work. It’s the suggestion that causalism should be amended in a way that doesn’t require causation. At first, this suggestion may sound absurd: How can causalism survive without causation, of all things? But I think that Moore is actually right about the main suggestion. I don’t think he’s right for the right reasons, but he’s still right (...) about the main idea. So, the aim of this paper is to explain how causalism can survive without causation, and how it may not. (shrink)

It is sometimes argued that there is an analogy between time and modality: What is true of time, mutatis mutandis, should be true of modality, and vice versa. However, I think that the importance of this analogy has not been truly appreciated in the literature. In this paper, I try to offer a plausible account of the relationship between time and modality based on what is known as presentist ersatzism. If the attempt succeeds, it will be shown that ersatzists about (...) time are better able to explain what possible worlds are. (shrink)

In a series of recent papers, Saul Smilansky has argued that compatibilists have no principled way of resisting the view that prepunishment is at least sometimes appropriate, thus revealing compatibilism to be a radical position, out of keeping with our ordinary moral judgments. Recent attempts to resist this conclusion seem to have overlooked the biggest problem with Smilansky’s argument, which is this: Smilanksy argues that the most obvious objection to prepunishment—namely, that it is inappropriate because it involves punishing the innocent (...) for crimes they have not committed—is unavailable to compatibilists. If compatibilism is true, he says, then if it is causally determined that someone is going to commit a crime, the fact that one has not yet done so is a mere temporal matter bearing no moral significance. I argue that there is no reason for compatibilists to accept this point. Compatibilists can (and should) resist Smilansky's claim that one’s not yet having committed a crime is morally insignificant and so resist the temptation to prepunish. (shrink)

(No abstract is available for this citation).

It is not uncommon in time travel stories to find that the mechanism by which the time travel is achieved is not invented. A time traveller could journey to his/her own past and give the designs of the time travel machine to his/her earlier self as s/he was given the designs as a younger person. These designs never get thought up by anyone. Such a situation would conflict with the usual conception of the acquisition of knowledge. This situation is called (...) the Temporal Epistemic Anomaly and would arise if knowledge is gained at a time prior to the information in question being transmitted but is not discovered or invented at any time. This article examines the implications of information propagating around a causal chain that is closed in time (which is required to create the Anomaly) and whether this information need have a specific origin point. (shrink)

Time Travel: Probability and Impossibility By EffinghamNikkOxford University Press, 2020. 256 pp.

H. G. Wells’ Time Traveller inhabits uniform Newtonian time. Where relativistic/quantum travelers into the past follow spacetime curvatures, past-bound Wellsians must reverse their direction of travel relative to absolute time. William Grey and Robin Le Poidevin claim reversing Wellsians must overlap with themselves or fade away piecemeal like the Cheshire Cat. Self-overlap is physically impossible but ‘Cheshire Cat’ fades destroy Wellsians’ causal continuity and breed bizarre fusions of traveler-stages with opposed time-directions. However, Wellsians who rotate in higher-dimensional space can reverse (...) temporal direction without self-overlap, Cheshire Cats or mereological monstrosities. Alas, hyper-rotation in Newtonian space poses dynamic and biological problems,. Controllable and survivable Wellsian travel needs topologically-variable spaces. Newtonian space, not Newtonian time, is Wellsians’ real enemy. (shrink)

In 1987, Roy Sorensen coined the term 'parahistory' to denote the study of genuinely anachronistic artefacts delivered by time travel.¹ 'Parahistory' would thus stand to history rather as parapsychology is claimed to stand to psychology, i.e. the parahistorian would study historical data that were obtained through channels that orthodox science does not recognise. How might one establish credentials as a time traveller? What sort of evidence could a time-traveller point to in support of claims that would presumably command a great (...) deal of scepticism? While successful predictions might be one confirmatory tool, supporting evidence needn't take the form of predictions. (Although Sorensen offers an intriguing argument that a Humean about miracle-testimony would be obliged to reject any testimony to the occurrence of time travel.) Perhaps artefacts that time travellers retrieve from other times (past or future) could usefully supplement testimonial or predictive evidence for the parahistorian. However, this paper will argue, any appeal to past-artefactual evidence for parahistorical claims faces a dilemma that threatens to undermine its value: appeals to past-artefact evidence must either collapse into appeals to predictive evidence or see their value diminished by such past artefacts' necessarily exhibiting contradictory indicators of age and period. (shrink)

_ Paradoxes of Time Travel _ By WassermanRyanOxford University Press, 2018. x + 250 pp.

Being alive throughout all history need not save you from dying, even if history extends infinitely into the past and future. Infinitely-long lives can fall short of genuine immortality and suffer all an ordinary mortal’s diminution in experience. Adapting David Lewis on time travel, Roy Sorensen imagines quasi-immortal ‘spore gods’, whose finite personal lives are distributed across infinite external time. While criticising the ‘Eleatic’ terms in which Sorensen presents spore gods, this paper argues his essential claims are correct: ‘spore god’ (...) worlds are logically and metaphysically possible. Indeed, going beyond Sorensen, spore gods are even nomologically accessible within General Relativity. (shrink)

Combining time travel with certain kinds of supertask, this paper proposes a novel model for Hell. Temporally-closed spacetimes allow otherwise impossible opportunities for material kinds of damnation and reveal surprising limitations on metaphysical objections to Hell. Prima facie, eternal damnation requires either infinite amounts of time or time for the damned to speed-up arbitrarily. However, spatiotemporally finite ‘time travel’ universes can host unending personal torment for infinitely many physical beings, while keeping fixed finite limits on rates of temporal passage. Such (...) ‘Hilbert's Inferno’ spacetimes suggest neither materialism nor the finitude of time and space need forbid Hell. A material Hell can be spatiotemporally finite yet eternal for its inhabitants. Hilbert's Inferno also sheds light on Hell's location and accessibility, and shows that some spacetimes are intrinsically better suited to punishment than reward. (shrink)

In 1987, Roy Sorensen coined the term “parahistory” to denote the hypothetical study of evidence retrieved via time travel. Parahistory would thus stand to history rather as parapsychology does to psychology; studying data (in this case artefacts) that are obtained in ways unrecognised by orthodox science. This paper considers future-derived parahistorical artefacts. Past/future asymmetries threaten irresolvable problems in calibrating future objects' periods, in dating future artefacts and insulating them from causal loops. In turn, causal loop objects at best cannot be (...) non-arbitrarily dated at all and at worst, cannot even be artefacts. Even if there can be evidence for travel from the future, any such evidence that appeals to future artefacts faces pervasive difficulties and is very unlikely to be compelling. (shrink)

In 1987, Roy Sorensen coined the term “parahistory” to denote the hypothetical study of evidence retrieved via time travel. Parahistory would thus stand to history rather as parapsychology does to psychology; studying data (in this case artefacts) that are obtained in ways unrecognised by orthodox science. This paper considers future-derived parahistorical artefacts. Past/future asymmetries threaten irresolvable problems in calibrating future objects' periods, in dating future artefacts and insulating them from causal loops. In turn, causal loop objects at best cannot be (...) non-arbitrarily dated at all and at worst, cannot even be artefacts. Even if there can be evidence for travel from the future, any such evidence that appeals to future artefacts faces pervasive difficulties and is very unlikely to be compelling. (shrink)

David Lewis famously argued that the time traveller ‘can’ murder her grandfather, even though she never will: it is compossible with a particular set of facts including her motive, opportunity and skill . I argue that while ordinary agents ‘can’ under Lewis’s conception, philosophers cannot – the latter will not only fail to fulfill their homicidal intentions but also fail to form them in the first place.

This paper outlines a new method for identifying folk intuitions to complement armchair intuiting and experimental philosophy, and thereby enrich the philosopher’s toolkit. This new approach—trope analysis—depends not on what people report their intuitions to be but rather on what they have made and engaged with; I propose that tropes in fiction reveal which theories, concepts and ideas we find intuitive, repeatedly and en masse. Imagination plays a dual role in both existing methods and this new approach: it enables us (...) to create the scenarios that elicit our intuitions, and also to mentally represent them. The method I propose allows us to leverage the imagination of the many rather than the few on both counts—scenarios are both created and consumed by the folk themselves. (shrink)

Extending work of Wittgenstein, Lakoff and Johnson I suggest that it is the metaphors we rely on in order to conceptualise time that provide an illusory space for time-travel-talk. For example, in the “Moving Time” spatialisation of time, “objects” move past the agent from the future to the past. The objects all move in the same direction – this is mapped to time always moving in the same direction. But then it is easy to imagine suspending this rule, and asking (...) why the objects should not start moving in the opposite direction. This is one way of generating the idea of time-travel “back” into the past. Time-travel-talk essentially involves the unaware projection of fragments of our time-talk – taken from powerful conceptual metaphors – onto the nature of reality itself. Understanding this dissolves away the charm and attractions of such talk. (shrink)

Fiona Woollard argues that when one is personally involved in an emergency, one has a moral requirement to make substantial sacrifices to aid others that one would not otherwise have. She holds that there are three ways in which one could be personally involved in an emergency: by being physically proximate to the victims of the emergency; by being the only person who can help the victims; or by having a personal encounter with the victims. Each of these factors is (...) claimed to be defeasibly sufficient to ground personal involvement, and thus a requirement of substantial sacrifice to aid. Woollard defends this view on the basis of a number of cases. We show that Woollard’s cases contain various confounding factors. In view of the more precisely drawn cases offered here, it is clear that neither proximity nor uniqueness nor personal encounter is intuitively defeasibly sufficient in the way Woollard claims. (shrink)

According to Richard Routley, a comprehensive theory of fiction is impossible, since almost anything is in principle imaginable. In my view, Routley is right: for any purported logic of fiction, there will be actual or imaginable fictions that successfully counterexample the logic. Using the example of ‘impossible’ fictions, I test this claim against theories proposed by Routley’s Meinongian contemporaries and also by Routley himself and his 21st century heirs. I argue that the phenomenon of impossible fictions challenges even today’s modal (...) Meinongians. (shrink)

The canonical version of possible worlds semantics for story prefixes is due to David Lewis. This paper reassesses Lewis's theory and draws attention to some novel problems for his account.

Core principles of mereology have been questioned by appealing to time travel scenarios. This paper questions the methodology of employing time travel scenarios to argue against mereology. We show some time travel scenarios are structurally equivalent to more standard ones not involving time travel; and that the three main theories about persistence through time can each solve both the time travel scenario as well as the structurally similar classical scenario. Time travel scenarios that are not similar to more standard arguments (...) are instead problematic because they are open to different, incompatible interpretations. We conclude that compared to the classical arguments against mereological principles, time travel scenarios do not add anything new. (shrink)

I will use paradox as a guide to metaphysical grounding, a kind of non-causal explanation that has recently shown itself to play a pivotal role in philosophical inquiry. Specifically, I will analyze the grounding structure of the Predestination paradox, the regresses of Carroll and Bradley, Russell's paradox and the Liar, Yablo's paradox, Zeno's paradoxes, and a novel omega plus one variant of Yablo's paradox, and thus find reason for the following: We should continue to characterize grounding as asymmetrical and irreflexive. (...) We should change our understanding of the transitivity of grounding in a certain sense. We should require foundationality in a new, generalized sense, that has well-foundedness as its limit case. Meta-grounding is important. The polarity of grounding can be crucial. Thus we will learn a lot about structural properties of grounding from considering the various paradoxes. On the way, grounding will also turn out to be relevant to the diagnosis (if not the solution) of paradox. All the paradoxes under consideration will turn out to be breaches of some standard requirement on grounding, which makes uniform solutions of large groups of these paradoxes more desirable. In sum, bringing together paradox and grounding will be shown to be of considerable value to philosophy.1. (shrink)

In this paper, I examine whether agents who commit testimonial injustice are morally responsible for their wrongdoing, given that they are ignorant of their wrongdoing. Fricker (2007) argues that agents whose social setting lacks the concepts or reasons necessary for them to correct for testimonial injustice are excused. I argue that agents whose social settings have these concepts or reasons available are also typically excused, because they lack the capacity to recognise those concepts or reasons. Attempts to trace this lack (...) of capacity back to an earlier culpable wrongdoing will often fail, due to there being no point at which these perpetrators knowingly chose to develop their prejudices. Attempts to ground culpability under Talbert’s (2008) Attributionist account of moral responsibility will also fail. This is because perpetrators’ lack of awareness of what they are doing makes it the case that they are not expressing objectionable evaluative judgments in the way required for blameworthiness. Finally, I argue that our temptation to blame agents who commit testimonial injustice is not completely unfounded. Appealing to Watson’s (1996) attributability/accountability distinction allows us to make sense of how some responses to the jurors are appropriate, despite their being excused. (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 considers a problem for dynamic presentism that has received little attention: its apparent inability to accommodate the duration of events (such as conscious experiences). After outlining the problem, I defend presentism from it. This defence proceeds in two stages. First, I argue the objection rests on a faulty assumption: that duration is temporal extension. The paper challenges that assumption on several different ways of conceiving of temporal extension. This is the negative case and forms the bulk of the (...) paper. Second, after diagnosing the error leading to the identification of duration with temporal extension, I outline a new presentist-friendly account of duration that avoids the problem. In particular, a non-reductive account of duration is offered that treats it as a primitive quality which bestows its possessor with a certain modal quality: that the possessor potentially does not change whilst there are changes in its environs. This is the positive case. Together the positive and negative cases provide presentism with an interesting and novel way of overcoming the problem of duration. (shrink)

We introduce the Causal Compatibility Conjecture for the Events, Trees, Histories approach to Quantum Theory in the semi-classical setting. We then prove that under the assumptions of the conjecture, points on closed causal curves are physically indistinguishable in the context of the ETH approach to QT and thus the conjecture implies a compatibility of the causal structures even in presence of closed causal curves. As a consequence of this result there is no observation that could be made by an observer (...) to tell any two points on a closed causal curve apart. We thus conclude that closed causal curves have no physical significance in the context of the ETH approach to QT. This is an indication that time travel will not be possible in a full quantum theory of gravity and thus forever remain a fantasy. (shrink)

ABSTRACTMany philosophers say that the nature of personal identity has to do with narratives: the stories we tell about ourselves. While different narrativists address different questions of personal identity, some propose narrativist accounts of personal identity over time. The paper argues that such accounts have troubling consequences about the beginning and end of our lives, lead to inconsistencies, and involve backwards causation. The problems can be solved, but only by modifying the accounts in ways that deprive them of their appeal.

Jack Spencer has recently argued for the striking thesis that, possibly, an agent is able to do the impossible—that is, perform an action that is metaphysically impossible for that person to perform. Spencer bases his argument on (Simple G), a case in which it is impossible for an agent G to perform some action but, according to Spencer, G is still intuitively able to perform that action. I reply that we would have to give up at least four action-theoretical principles (...) if we accept that G is able to do the impossible. We may be best off retaining the principles and thus rejecting Spencer's intuition that G is able to do the impossible. I then consider an argument for the claim that G is able to do the impossible that goes through the Snapshot Principle. I, however, deny that any true variant of the Snapshot Principle shows that G is able to do the impossible. Moreover, the counterexample to the Snapshot Principle that I develop also suggests that G is unable to do the impossible in (Simple G). The most natural explanation for why an agent is unable to perform some action in this counterexample extends to (Simple G). Next, I develop three error theories for why we might initially share Spencer's intuition that G is able to do the impossible in (Simple G). Finally, I consider a couple other "G-cases" of Spencer's and find them all wanting. Perhaps we are unable to do the impossible. (shrink)

I argue that perceptual content is always affected by the allocation of one’s attention. Perception attributes determinable and determinate properties to the perceived scene. Attention makes (or tries to make) our perceptual attribution of properties more determinate. Hence, a change in our attention changes the determinacy of the properties attributed to the perceived scene.

The fission of a person involves what common sense describes as a single person surviving as two distinct people. Thus, say most metaphysicians, this paradox shows us that common sense is inconsistent with the transitivity of identity. Lewis’s theory of overlapping persons, buttressed with tensed identity, gives us one way to reconcile the common sense claims. Lewis’s account, however, implausibly says that reference to a person about to undergo fission is ambiguous. A better way to reconcile the claims of common (...) sense, one that avoids this ambiguity, is to recognize branching persons, persons who have multiple pasts or futures. (shrink)

On a Molinist account of creation and providence, not only is there is a complete set of truths about what every possible person would freely do in any possible set of circumstances, but these conditional truths are part of the very explanation of our existence. Robert Adams has recently argued that the explanatory priority of these conditionals undermines libertarian freedom. In the present essay, I take at close look at Adams’ argument and at the Molinist response of Thomas Flint. After (...) showing that Flint’s response is inadequate, I develop what I believe to be a more successful Molinist response to Adams’ argument. Along the way, I seek to provide some insight into the nature of libertarian freedom and the proper interpretation of the much discussed “principle of alternate possibilities.”. (shrink)

It is widely held that the classic reassembly model of resurrection faces intractable problems. What happens to someone if God assembles two individuals at the resurrection which are equally good candidates for being the original person? If two or more people, such as a cannibal and the cannibal’s victim, were composed of the same particles at their respective deaths, can they both be resurrected? If they can, who gets the shared particles? And would an attempt to reassemble a long-gone individual (...) result in a genuine resurrection, or merely an intrinsic duplicate of the original person? In this paper, I argue that the first of these problems has, in effect, been solved by defenders of a rival view; I propose a novel solution to the second problem; and I show that the third can be solved by upgrading the naïve reassembly model to a novel variety of reassembly model. (shrink)

The recent literature on the nature of persistence features a handful of imaginative cases in which an object seems to colocate with itself. So far, discussion of these cases has focused primarily on how they defy the standard endurantist approaches to the problem of temporary intrinsics. But in this article, I set that issue aside and argue that cases of apparent self-colocation also pose another problem for the endurantist. While the perdurantist seems to have a fairly straightforward account of self-colocation, (...) the endurantist has a hard time saying exactly what it would be for an object to be self-colocated. After introducing this problem and explaining how the perdurantist can circumvent it with little difficulty, I discuss a number of tempting endurantist solutions that ultimately fail. Then I suggest an endurantist solution which I think is more promising, but which requires the endurantist to deny that apparent cases of self-colocation are genuine cases of self-colocation. (shrink)

Some philosophers defend the possibility of synchronic multilocation, and have even used it to defend other substantive metaphysical theses. But just how strong is the case for the possibility of synchronic multilocation? The answer to this question depends in part on whether synchronic multilocation is wedded to other controversial metaphysical notions. In this paper, I consider whether the possibility of synchronic multilocation depends on the possibility of time travel, and I conclude that the answer hinges on the nature of time (...) and persistence. (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.

It is often thought that presentism is incompatible with time travel. I will argue that this common view is incorrect. Specifically, I will argue that presentism is compatible with some stories that involve closed timelike curves, and that some of these stories are time-travel stories.

In a recent paper in this journal, McCall and Lowe (2003) argue that an understanding of Special Relativity reveals that the A theorist’s notion of temporal passage is consistent with the B theory of time. They arrive at this conclusion by considering the twins’ paradox, where one of two twins (T) travels to Alpha Centauri and back and upon her return has aged 30 years, while her earth-bound twin (S) has aged 40 years. This paper argues that their account of (...) temporal passage fails to reconcile the A theoretic notion of temporal passage with the B theory of time since the B theorist is at liberty to adopt this as an account of temporal passage as understood by the B theorist. (shrink)

In a recent paper in this journal, McCall and Lowe (2003) argue that an understanding of Special Relativity reveals that the A theorist’s notion of temporal passage is consistent with the B theory of time. They arrive at this conclusion by considering the twins’ paradox, where one of two twins (T) travels to Alpha Centauri and back and upon her return has aged 30 years, while her earth-bound twin (S) has aged 40 years.Does this reconcile the A theoretic notion of (...) temporal passage with the B theory of time? I argue not. (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)

It is possible to wholly exist at multiple spatial locations at the same time. At least, if time travel is possible and objects endure, then such must be the case. To accommodate this possibility requires the introduction of a spatial analog of either relativising properties to times—relativising properties to spatial locations—or of relativising the manner of instantiation to times—relativising the manner of instantiation to spatial locations. It has been suggested, however, that introducing irreducibly spatially relativised or spatially adverbialised properties presents (...) some difficulties for the endurantist. I will consider an objection according to which embracing such spatially relativised properties could lead us to reject mereology altogether in favour of a metaphysics according to which objects are wholly present at every space-time point at which they exist. I argue that although such a view is coherent, there are some good reasons to reject it. Moreover, I argue that the endurantist can introduce spatially relativised or adverbialised properties without conceding that objects lack spatial parts. Such a strategy has the additional advantage that it allows the endurantist not only to explain time travel, but also to reconcile our competing intuitions about cases of fission. (shrink)