Might time be multi‐dimensional? In exploring this question, this paper uses a thought‐experiment about dimensionality, H. G. Wells' ‘The Plattner Story’. Plattner has his left and right sides transposed after a trip through a fourth spatial dimension, a change with independent empirical consequences. This example is then generalised to reversals of the directions of time and entropy. Finally, this thought‐experiment is related to relativistic theories of time and the possibility of preserving causality in a temporally multi‐dimensional framework.

This paper looks at Kurt Gödel's causally‐pathological cosmological models (derived from general relativity), in the light of anthropic explanations. If a Gödelian world is a possible world, could anthropic reasoning shed any light on whether or not our world is Gödelian? This paper argues that while there are some good anthropic reasons why our world ought to be Gödelian, too many observations suggest that our world can’t possibly be Gödelian in fact. If Gödel's world is a possible one, anthropic teleology (...) alone cannot explain why it isn’t the world we inhabit. Furthermore, if our world were Gödelian, anthropic arguments against the existence of extraterrestrial intelligences would imply a bleak human future. En route, some general objections to relativistic causal pathologies are addressed and some anthropic arguments to the effect that Gödelian worlds couldn’t sustain life are also addressed and dismissed. (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)

This paper attempts three tasks in relation to Carter and Leslie's Doomsday Argument. First, it criticises Timothy Chambers' 'Ussherian Corollary', a striking but unsuccessful objection to standard Doomsday arguments. Second, it reformulates the Ussherian Corollary as an objection to Bradley Monton's variant Doomsday and Nick Bostrom's Simulation Argument. Finally, it tries to diagnose the epistemic/metaphysical problems facing Doomsday-related arguments.1.

Inspired by anthropic reasoning behind Doomsday arguments, Nick Bostrom's Simulation Argument says: people who think advanced civilisations would run many fully-conscious simulated minds should also think they're probably simulated minds themselves. However, Bostrom's conclusions can be resisted, especially by sympathisers with Doomsday or anthropic reasoning. This paper initially offers a posterior-probabilistic ‘Doomsday lottery’ argument against Bostrom's conclusions. Suggestions are then offered for deriving anti-simulation conclusions using weaker assumptions. Anti-simulation arguments herein use more robust reference classes than Bostrom's argument, require no (...) Principles of Indifference, abide better by the total evidence requirement, and yet use empirically plausible priors and likelihoods. However, while Doomsday arguments are probabilistically, epistemically and metaphysically stronger than the Simulation Argument, anthropic reasoning can refrain from embracing either. (shrink)

“Recognizing that prisons disproportionately confine sick people, with mental illness, substance abuse, HIV disease among other illnesses; and that prisoners are subject to further morbidity and mortality in these institutions, due to lack of access and/or resources for health care, overcrowding, violence, emotional deprivation, and suicide.… condemns the social practice of mass imprisonment.”After decades of steady decline, tuberculosis has emerged as a significant public health threat in the United States. The rising rates of tuberculosis cases, an increasing proportion of which (...) are resistant to standard chemotherapies, are linked to the many scourges threatening our communities: the explosion of poverty, drug use, violence, the HIV epidemic, and the concomitant rise in congregate housing including homeless shelters, residential drug treatment programs and incarceration facilities. Jails and prisons have disproportionately high rates of tuberculosis infection and have been implicated as points of tuberculosis spread and, as such, are a critical point for tuberculosis control interventions. (shrink)

In the place of an introduction to part 5 of the Common Knowledge symposium on forms of quietism, the journal's editor and one of its longtime columnists discuss, in dialogue format, the case of Thomas More. Could he have evaded martyrdom at the hands of Henry VIII and Thomas Cromwell? One discussant argues that More could not have done so without contemptibly abandoning his principles and surrendering fully to despotism. The other discussant disagrees, suggesting that More had to abandon some (...) of his principles one way or the other—in resisting despotism, however quietly, More did serious harm to his wife and daughter, to the European humanist movement, and to the cause of English Catholics. (shrink)

We present a general framework for analyzing the contribution to reproductive success of a behavioural action. An action may make a direct contribution to reproductive success, but even in the absence of a direct contribution it may make an indirect contribution by changing the animal's state. We consider actions over a period of time, and define a reward function that characterizes the relationship between the animal's state at the end of the period and its future reproductive success. Working back from (...) the end of the period using dynamic programming, the optimal action as a function of state and time can be found. The procedure also yields a measure of the cost, in terms of future reproductive success, of a suboptimal action. These costs provide us with a common currency for comparing activities such as eating and drinking, or eating and hiding from predators. The costs also give an indication of the robustness of the conclusions that can be drawn from a model. We review how our framework can be used to analyze optimal foraging decisions in a stochastic environment. We also discuss the modelling of optimal daily routines and provide an illustration based on singing to attract a mate. We use the model to investigate the features that can produce a dawn song burst in birds. State is defined very broadly so that it includes the information an animal has about its environment. Thus, exploration and learning can be included within the framework. (shrink)

Alasdair Richmond introduces some famous paradoxes about time travel.

Following on from Nick Bostrom's discussion of the Doomsday argument, Alasdair Richmond considers how anthropic reasoning can lead from Doomsday to some odd conclusions about computation and our place in reality.

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)

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)

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)

Around 1998, internet postings began appearing under the alias ‘ Timetravel_0 ’. This alias was later replaced by ‘John Titor’, and it's as such I'll designate the posts' author. Remarkably, Titor claimed to have time-travelled from 2036 on a mission to retrieve an IBM 5100 in 1975. Titor refrained from public appearances and any evidence for his story remains web-bound but before closing shop c. March 24 th 2001, he described various future events, e.g.: Y2K is a disaster. Many people (...) die on the highways when they freeze to death trying to get to warmer weather. Cancellation of the Olympics after 2004 due to world conflict. America will soon be engaged in civil war with itself; a civil war that we'll see the beginnings of during 2004 and 2005, escalating until it is indisputable by 2008. This equivocal civil war fizzles until global nuclear war kills three billion people in 2015. (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)

Note on the text of the principles -- Context -- Biography -- Berkeley's philosophical background -- Overview of themes -- Teading the text -- The principles : introduction -- The principles : part one -- The objects and subject of knowledge : ideas and spirit -- Unperceived existence : a nicer strain of abstraction -- Problems for materialism -- A Cartesian dream argument -- The master argument -- From the inertness of ideas to the existence of God -- Philosophical objections (...) to immaterialism and replies -- Religious objections to immaterialism and replies -- Further advantages of immaterialism -- Great provinces of speculative science -- The attack on absolute space -- Mathematics -- Other minds -- The divine language of nature -- Reception and influence -- Guide to further reading. (shrink)

The philosophy of time travel has an illustrious pedigree, having seen ground-breaking physical and philosophical treatments in the late 1940s and early 1950s from Kurt Gödel [...].

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

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

A general framework for analysing the effects of variability and the effects of interruptions on foraging is presented. The animal is characterised by its level of energetic reserves, x. We consider behaviour over a period of time [0,T]. A terminal reward function R(x) determines the expected future reproductive success of an animal with reserves x at time T. For any state x at a time in the period, we give the animal a choice between various options and then constrain it (...) to follow a background strategy. The best option is the one that maximizes expected future reproductive success. Using this framework, we show that sensitivity to variability in amount of energy gained is logically distinct from sensitivity to variability in the time at which food is obtained. We also show that incorporating interruptions results in both a preference for variability in time and a preference for a reward followed by a delay as opposed to the same delay before the reward. (shrink)

Rolls discusses various adaptive explanations of physiological processes and the emotions. We give a critical analysis of some of these from the perspective of behavioural ecology. While agreeing with the approach adopted by Rolls, we identify topics that could have been better presented by making use of the existing literature.

John Maynard Smith was the founder of evolutionary game theory. He has also been the major influence on the direction of this field, which now pervades behavioural ecology and evolutionary biology. In its original formulation the theory had three components: a set of strategies, a payoff structure, and a concept of evolutionary stability. These three key components are still the basis of the theory, but what is assumed about each component is often different to the original assumptions. We review modern (...) approaches to these components. We emphasis that if a game is considered in isolation, and arbitrary payoffs are assumed, then the payoffs may not be consistent with other components of the system which are not modelled. Modelling the whole system, including not only the focal game, but also the future behaviour of the players and the behaviour of other population members, allows a consistent model to be constructed. We illustrate this in the case of two models of parental care, showing how linking a focal game to other aspects of the system alters what is predicted. (shrink)

Importance Informed consent is essential to ethical, rigorous research and is important to recruitment and retention in cancer trials.Objective To examine cancer clinical trial (CCT) participants’ perceptions of informed consent processes and variations in perceptions by cancer type.Design and Setting and Participants Cross-sectional survey from mixed-methods study at National Cancer Institute–designated Northeast comprehensive cancer center. Open-ended and forced-choice items addressed: (1) enrollment and informed consent experiences and (2) decision-making processes, including risk-benefit assessment. Eligibility: CCT participant with gastro-intestinal or genitourinary, hematologic-lymphatic (...) malignancies, lung cancer, and breast or gynecological cancer (N = 334).Main Outcome Measures Percentages satisfied with consent process and information provided; and assessing participation’s perceptions of risks/benefits. Multivariable logistic or ordinal regression examined differences by cancer type.Results Most patient-participants felt well informed by the consent process (more than 90% overall and by cancer type) and. most (87.4%) reported that the consent form provided all the information they wanted, although nearly half (44.8%) reported that they read the form somewhat carefully or less. More than half (57.9%) said that talking to research staff (i.e., the consent process) had a greater impact on participation decisions than reading the consent form (2.1%). A third (31.1%) were very sure of joining in research studies before the informed consent process (almost half of lung cancer patients did—47.1%). Most patients personally assessed the risks and benefits before consenting. However, trust in physicians played an important role in the decision to enroll in CCT.Conclusions and Relevance Cancer patients rely less on written features of the informed consent process than on information obtained from the research staff and their own physicians. Research should focus on information and communication strategies that support informed consent from referring physicians, researchers, and others to improve patient risk-benefit assessment and decision-making. (shrink)

Book reviewed in this article: The Seven Deadly Sins: Society and Evil. By Stanford M. Lyman. The Seven Deadly Sins Today. By Henry Fairlie.

Philosophy for Everyone begins by explaining what philosophy is before exploring the questions and issues at the foundation of this important subject.Key topics and their areas of focus include:Epistemology - what our knowledge of the world and ourselves consists in, and how we come to have it;Philosophy of Science - foundational conceptual issues in scientific research and practice;Philosophy of Mind - what it means for something to have a mind, and how minds should be understood and explained;Moral Philosophy - the (...) nature of our moral judgements and reactions, whether they aim at some objective moral truth, or are mere personal or cultural preferences, and;Metaphysics - fundamental conceptual questions about the nature of reality.Designed to be used on the corresponding Introduction to Philosophy online course offered by The University of Edinburgh, this book is also highly recommended to anyone looking for a short overview of this fascinating discipline. (shrink)