Craig Callender

In a classical mechanical world, the fundamental laws of nature are reversible. The laws of nature treat the past and future as mirror images of each other. Temporally asymmetric phenomena are ultimately said to arise from initial conditions. But are the laws of nature also reversible in a quantum world? This paper argues that they are not, that time in a quantum world prefers a particular 'hand' or ordering. I argue, first, that the probabilistic algorithm used in the theory picks out a preferred direction of time for almost all interpretations of the theory, and second, that contrary to the received wisdom the Schr?dinger evolution is also irreversible. The status of Wigner reversal invariance is then discussed. I conclude that the quantum world is fundamentally irreversible, but manages to appear reversible at the classical level.

A persistent question about the deBroglie–Bohm interpretation of quantum mechanics concerns the understanding of Born’s rule in the theory. Where do the quantum mechanical probabilities come from? How are they to be interpreted? These are the problems of emergence and interpretation. In more than 50 years no consensus regarding the answers has been achieved. Indeed, mirroring the foundational disputes in statistical mechanics, the answers to each question are surprisingly diverse. This paper is an opinionated survey of this literature. While acknowledging the pros and cons of various positions, it defends particular answers to how the probabilities emerge from Bohmian mechanics and how they ought to be interpreted.

For much of this century, philosophers hoped that Einstein’s general theory of relativity would play the role of physician to philosophy. Its development would positively influence the philosophy of methodology and confirmation, and its ontology would answer many traditional philosophical debates—for example, the issue of spacetime substantivalism. In physics, by contrast, the attitude is increasingly that GTR itself needs a physician. The more we learn about GTR the more we discover how odd are the spacetimes that it allows. Not only does GTR permit singularities, naked and clothed, but it allows time travel, topology change, and event and particle horizons, to name but a few of these oddities. Rather than revel in the riches of the theory, however, many physicists seek to rule out one or more of the above “pathologies” on the grounds that they are “physically unreasonable.” Thus contemporary researchers hawk various “cures” for the “illnesses” of GTR: among them, Chronology Protection to ensure against time travel, Cosmic Censorship for naked singularities, Inflation for horizons, and so on. The physics of these illnesses and cures, and the problems they engender, are the source of much controversy in the physics literature. Philosophers have largely neglected it. But clearly the subject needs philosophers of physics to determine whether the patient is genuinely ailing, and if so, to sift the real antidotes from the snake oil.

ABSTRACT:Autistic adults suffer from an alarmingly high and increasing unemployment rate. Many companies use pre-employment personality screening tests. These filters likely have disparate impacts on neurodivergent individuals, exacerbating this social problem. This situation gives rise to a bind. On the one hand, the tests disproportionately harm a vulnerable group in society. On the other, employers think that personality test scores are predictors of job performance and have a right to use personality traits in their decisions. It is difficult to say whether these negative disparate impacts are a case of wrongful discrimination. Nevertheless, we will show that pre-employment personality tests prey on several features of autism in an unfair way, and for this reason, we suggest the contours of some regulation that we deem necessary.

For much of this century, philosophers hoped that Einstein’s general theory of relativity would play the role of physician to philosophy. Its development would positively influence the philosophy of methodology and confirmation, and its ontology would answer many traditional philosophical debates—for example, the issue of spacetime substantivalism. In physics, by contrast, the attitude is increasingly that GTR itself needs a physician. The more we learn about GTR the more we discover how odd are the spacetimes that it allows. Not only does GTR permit singularities, naked and clothed, but it allows time travel, topology change, and event and particle horizons, to name but a few of these oddities. Rather than revel in the riches of the theory, however, many physicists seek to rule out one or more of the above “pathologies” on the grounds that they are “physically unreasonable.” Thus contemporary researchers hawk various “cures” for the “illnesses” of GTR: among them, Chronology Protection to ensure against time travel, Cosmic Censorship for naked singularities, Inflation for horizons, and so on. The physics of these illnesses and cures, and the problems they engender, are the source of much controversy in the physics literature. Philosophers have largely neglected it. But clearly the subject needs philosophers of physics to determine whether the patient is genuinely ailing, and if so, to sift the real antidotes from the snake oil.

Two females, Nadine and Fatu, are the sole surviving Northern White Rhinos (NWR). The subspecies is functionally extinct. Hope for NWR now lies in emerging reproductive and genetic technologies, which could potentially produce NWR from induced pluripotent stem cells. What is the rationale for this project? This question raises almost every philosophical issue facing conservation science today. I argue that NWR recovery is hard to justify via many traditional paths (e.g., historical fidelity, ecosystem health, biodiversity), but if we shift focus to white rhinos in general or even mammals then clear benefits emerge.

How should one discount utility across time? The conventional wisdom in social science is that one should use an exponential discount function. Such a function is a representation of the axioms that provide a well-defined utility function plus a condition known as stationarity. Yet stationarity doesnt really have much intuitive normative pull on its own. Here I try to cast it in a normative glow by deriving stationarity from two explicitly normative premises, both suggested by the philosophical thesis of temporal neutralism. Putting the argument in this form helps us better understand exponential discounting and challenges to it.

Why does time seem to flow in one direction? Can we influence the past? Is only the present real? Does relativity conflict with our common understanding of time? How does time relate to free will? Could science do away with time? These questions and others about time are among the most puzzling problems in philosophy and science. In this exciting collection of original articles, eminent philosophers propose novel answers to these and other questions. Based on the latest research in philosophy and physics, these essays will be enjoyable to anyone with a speculative turn of mind.

This thesis is an attempt to accurately formulate and solve one of the problems associated with the direction of time. Processes in nature appear to be 'irreversible', for instance, heat flows from hot to cold but never from cold to hot. The problem of the direction of time, roughly put, is the difficulty of squaring this irreversible behavior with the apparent fact that the fundamental laws of physics are completely reversible. ;In the first three chapters I critically review the foundations of statistical mechanics. After arguing that entropy is an objective property of the thermodynamic world, I contrast the 'Boltzmannian' single-system approach to statistical mechanics with the 'Gibbsian' many-system approach. Based in part on its ability to handle irreversibility, I judge the Boltzmann approach to be superior from a philosophical perspective. I argue, however, that the statistical mechanical probabilities cannot be interpreted in such a way as to allow the theory to give the sort of explanation originally desired. ;The next four chapters are devoted to the direction of time. Chapters four and five attempt to provide the problem with the philosophically mature geography that has so far eluded it. Chapter six discusses the problem in the context of quantum mechanics, and chapter seven criticizes the problem's standard formulation. I show that the problem is really a much more general one than has previously been appreciated; indeed, I try to show that it is a problem afflicting all the special sciences. ;Finally, the remaining three chapters investigate three separate issues. Chapter eight discusses the tensed theory of time. I claim the best argument for the tensed theory relies on various temporal asymmetries, e.g., the asymmetry of causation. I provide reasons for not being persuaded by this argument. The tensed theory, I conclude, is not incoherent, as many have claimed, instead it is simply an implausible explanation of our experience. Chapter nine examines the possibility that quantum mechanics implies our world is temporally anisotropic, and chapter ten looks at some conceptual difficulties associated with our conception of time reversal invariance