In our current unstable world, nuclear warfare, climate crises, and techno nihilism are three perilous clouds hovering over an anxious humanity. In this article I examine our current state of affairs with regard to the imminent risk of nuclear holocaust, rapid climate emergencies destroying the planet, and the cultural and political consequences of emerging technologies on the fate of civilization. In the wake of innumerable existential threats to the future of our world, I revisit the plausibility of the Doomsday (...) Argument, which predicts the end of human existence. (shrink)

One.The Glass is Always Half-full? Countering the Optimists -- Two. The `Doomsday Clock' is Always with Us: Pessimism in History -- Three. Optimists v. Pessimists: Economics and Politics -- Four. I Think, Therefore I Expect the Worst: Pessimism in Philosophy -- Five. A World Without Meaning: Pessimism in Literary Fiction -- Six. Visions of Despair: Pessimism in the Arts -- Seven. The Benefits of a Half-empty Glass: Pessimism as a Lifestyle.

In January 2023, the Science and Security Board of the Bulletin of the Atomic Scientists moved the hands of the Doomsday Clock forward to 90 s before midnight.

Previous research has reported that ethical values of business students are lower than those of their peers in other majors. The purpose of this study was to investigate whether a self-selection bias with respect to ethical values exists among students enrolled as business majors when compared with students planning to enter the engineering profession. Engineering students are exposed to a similar technical orientation in academic curricula and also supply the market for managers.A survey instrument was administered to 195 students enrolled (...) in undergraduate business and engineering programs and a graduate business program. The research instrument measured how business and engineering students perceive their own ethical beliefs and actions and how they perceived the ethical beliefs and actions of their peers. (shrink)

O artigo traz resultados de uma investigação de mestrado que teve por objetivo pesquisar as concepções de um grupo de professores a respeito das funções que os mesmos exercem frente à sociedade contemporânea. Partiu-se da premissa de que suas concepções guardam relação com suas práticas educativas e pedagógicas. Trata-se de uma pesquisa desenvolvida na perspectiva qualitativa, com cinquenta e um professores que atuam em seis escolas estaduais da cidade de Ponta Grossa-PR. Elegeu-se como aporte teórico autores que tratam da formação (...) de professores e da profissão docente, como Freire, Imbernón, Ens e Behrens, Tozetto, Sacristán e Tedesco. Os dados foram coletados por meio de questionários, categorizados e analisados seguindo os pressupostos na Análise de Conteúdo. Três categorias foram configuradas a partir de significantes presentes nas respostas dos professores participantes: Categoria I – Professor como um sujeito transformador: educação em uma forma ampla, Categoria II – Professor como profissional do conhecimento, e Categoria III – Professor enquanto sujeito que desempenha vários papéis sociais. Essas categorias nos possibilitaram inferir que as concepções dos professores em relação ao seu papel na sociedade contemporânea vão além da função social da escola, pois centram-se primeiramente na figura de um profissional transformador do mundo; seguida da noção de profissional do conhecimento e, por fim, da ideia de um profissional que desempenha vários papéis sociais. A pesquisa também apontou uma necessária redefinição da profissão docente para que os professores assumam novas competências profissionais na contemporaneidade. Palavras-chave: Profissão docente. Função dos professores. Sociedade contemporânea. Concepções. (shrink)

This paper considers the argument according to which, because we should regard it as a priori very unlikely that we are among the most important people who will ever exist, we should increase our confidence that the human species will not persist beyond the current historical era, which seems to represent a crucial juncture in human history and perhaps even the history of life on earth. The argument is a descendant of the Carter-Leslie Doomsday Argument, but I show that (...) it does not inherit the crucial flaw in its immediate ancestor. Nonetheless, we are not forced to follow the argument where it leads if we instead significantly decrease our confidence that we can affect the long-run future of humanity. GPI Working Paper No. 1-2019. (shrink)

“Doomsday prepping” is a phenomenon which involves preparing for feared societal collapse by stockpiling resources and readying for self-sufficiency. While doomsday prepping has traditionally been reported in the context of extremists, during the COVID-19 pandemic, excessive stockpiling leading to supply shortages has been reported globally. It is unclear what psychological or demographic factors are associated with this stockpiling. This study investigated doomsday prepping beliefs and behaviors in relation to COVID-19 proximity, demographics, coping strategies, psychopathology, intolerance of uncertainty (...) (IU), and personality in 384 participants (249 female) in an online study. Participants completed a number of questionnaires including the Post-Apocalyptic and Doomsday Prepping Beliefs Scale and a scale designed for the current study to measure prepping in the context of COVID-19. These were analyzed using ANOVAs, correlational, and mediation analyses to examine relationships between psychometric variables and stockpiling. Prepping beliefs and behaviors were higher in males than females and positively associated with anxiety, obsessive-compulsive symptoms, IU, and traditional masculinity traits. Older age, male gender, obsessive-compulsive symptoms, and traditional masculinity predicted unique variance in prepping. The relationship between gender and stockpiling was mediated by social learning (witnessing other people panic buying) and the perceived threat of COVID-19 (doomsday interpretations) while proximity and personal vulnerability to COVID-19 were non-significant. Results indicate that panic buying was influenced more by witnessing others stockpiling, personality, and catastrophic thinking rather than by proximity to danger. Education could target these factors in ongoing waves of the pandemic or future catastrophes. (shrink)

The Doomsday Argument and the Simulation Argument share certain structural features, and hence are often discussed together. Both are cases where reflecting on one’s location among a set of possibilities yields a counter-intuitive conclusion—in the first case that the end of humankind is closer than you initially thought, and in the second case that it is more likely than you initially thought that you are living in a computer simulation. Indeed, the two arguments do have some structural similarities. But (...) there are also significant disanalogies between the two arguments, and I argue that these disanalogies mean that the Simulation Argument succeeds and the Doomsday Argument fails. (shrink)

This chapter provides a brief version of the mathematician Brandon Carter's “doomsday argument”, a probabilistic argument that attempts to predict the future lifetime of the human race given an estimate of the total number of humans born thus far. It challenges Carter's argument by stating the crucial point that we ought (until we find enough contrary evidence) to try to see ourselves as “fairly ordinary” inside the various classes into which we fall ‐ bearing in mind, naturally, that in (...) some cases there might be tradeoffs to be made because being more ordinary inside one class might involve being less ordinary inside another. Even if humans were statistically very unusual among all observers scattered through space and time, observers falling into vastly many different species, there might still be nothing too odd in being a human rather than a member of some other intelligent species. (shrink)

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)

The Doomsday argument purports to show that the risk of the human species going extinct soon has been systematically underestimated. This argument has something in common with controversial forms of reasoning in other areas, including: game theoretic problems with imperfect recall, the methodology of cosmology, the epistemology of indexical belief, and the debate over so-called fine-tuning arguments for the design hypothesis. The common denominator is a certain premiss: the Self-Sampling Assumption. We present two strands of argument in favor of (...) this assumption. Through a series of thought experiments we then investigate some bizarre prima facie consequences – backward causation, psychic powers, and an apparent conflict with the Principal Principle. (shrink)

Lewis’s Principal Principle says that one should usually align one’s credences with the known chances. In this paper I develop a version of the Principal Principle that deals well with some exceptional cases related to the distinction between metaphysical and epistemic modal­ity. I explain how this principle gives a unified account of the Sleeping Beauty problem and chance-­based principles of anthropic reasoning. In doing so, I defuse the Doomsday Argument that the end of the world is likely to be (...) nigh. GPI Working Paper No. 8-2021. (shrink)

English translation of a paper originally published in French in the Canadian Journal of Philosophy under the title 'Comment l'urne de Carter et Leslie se déverse dans celle de Hempel'. In this paper, I present firstly a solution to Hempel's Problem. I recall secondly the solution to the Doomsday Argument described in my previous Une Solution pour l'Argument de l'Apocalypse (Canadian Journal of Philosophy, 1998) and remark that both solutions are based on a similar line of reasoning. I show (...) thirdly that the Doomsday Argument can be reduced to the core of Hempel's Problem. (shrink)

Circalunar clocks, which allow organisms to time reproduction to lunar phase, have been experimentally proven but are still not understood at the molecular level. Currently, a new generation of researchers with new tools is setting out to fill this gap. Our essay provides an overview of classic experiments on circalunar clocks. From the unpublished work of the late D. Neumann we also present a novel phase response curve for a circalunar clock. These experiments highlight avenues for molecular work and (...) call for rigor in setting up and analyzing the logistically complex experiments on circalunar clocks. Re‐evaluating classic experiments, we propose that (1) circalunar clocks in different organisms will have divergent mechanisms and physiological bases, (2) they may have properties very different from the well‐studied circadian clocks and (3) they may have close mechanistic and molecular relations to seasonal rhythms and diapause. (shrink)

This paper aims at tracking down, by looking at late medieval and early modern discussions over the ontological status of artifacts, the main steps of the process through which nature became theorized on a mechanistic model in the early 17th century. The adopted methodology consists in examining how inventions such as mechanical clocks and automata forced philosophers to modify traditional criteria based on an intrinsic principle of motion and rest for defining natural beings. The paper studies different strategies designed in (...) the transitional period 1300–1600 for making these inventions compatible with classical definitions of nature and artifacts. In the first part of the paper, it is shown that, even if virtually all medieval philosophers acknowledged an ontological distinction between artifacts and natural beings, these different strategies demonstrate a growing concern about the consistency of the art/nature distinction. The next part of the paper studies how mechanical clocks, even before the Scientific Revolution, served as theoretical models for applying mechanistic views to different objects (be they cosmological, physical or biological). The epistemological function of clocks appears to stem from different factors (like the specific manufacturing of late medieval clocks as well as the evolution of 16th-century mechanics) that are listed in this second part of the paper. These factors, combined with the definitional issues raised by automata, explain that clocks became the symbol of a new approach to natural philosophy, characterized by the collapse of the art/nature distinction and the “mechanization of nature”. (shrink)

The clock hypothesis of relativity theory equates the proper time experienced by a point particle along a timelike curve with the length of that curve as determined by the metric. Is it possible to prove that particular types of clocks satisfy the clock hypothesis, thus genuinely measure proper time, at least approximately? Because most real clocks would be enormously complicated to study in this connection, focusing attention on an idealized light clock is attractive. The present paper extends (...) and generalized partial results along these lines with a theorem showing that, for any timelike curve in any spacetime, there is a light clock that measures the curve’s length as accurately and regularly as one wishes. (shrink)

The Carter-Leslie Doomsday argument, as standardly presented, relies on the assumption that you have knowledge of your approximate birth rank. I demonstrate that the Doomsday argument can still be given in a situation where you have no knowledge of your birth rank. This allows one to reply to Bostrom's defense of the Doomsday argument against the refutation based on the idea that your existence makes it more likely that many observers exist.

Cellular circadian clocks represent ancient anticipatory systems which co‐evolved with the first cells to safeguard their survival. Cyanobacteria represent one of the most ancient cells, having essentially invented photosynthesis together with redox‐based cellular circadian clocks some 2.7 billion years ago. Bioelectricity phenomena, based on redox homeostasis associated electron transfers in membranes and within protein complexes inserted in excitable membranes, play important roles, not only in the cellular circadian clocks and in anesthetics‐sensitive cellular sentience (awareness of environment), but also in the (...) coupling of single cells into tissues and organs of unitary multicellular organisms. This integration of cellular circadian clocks with cellular basis of sentience is an essential feature of the cognitive CBC‐Clock basis of cellular life. (shrink)

Branching time is a popular theory of time that is intended to account for the openness of the future. Generally, branching-time models the openness of the future by positing a multiplicity of concrete alternative futures mirroring all the possible ways the future could unfold. A distinction is drawn in the literature among branching-time theories: those that make use of moment-based structures and those that employ history-based ones. In this paper, I introduce and discuss a particular kind of openness relative to (...) the possibility that time ends (doomsday). I then show that whereas moment-based branching structures cannot represent this kind of openness, history-based structures can account for it. The conclusion is that history-based structures have an advantage over moment-based ones. (shrink)

If the human race comes to an end relatively shortly, then we have been born at a fairly typical time in the history of humanity; if trillions of people eventually exist, then we have been born in the first surprisingly tiny fraction of all people. According to the 'doomsday argument' of Carter, Leslie, Gott and Nielsen, this means that the chance of a disaster which would obliterate humanity is much larger than usually thought. But treating possible observers in the (...) same way as those who actually exist avoids this conclusion: our existence is more likely in a race which is long-lived, and this cancels out the doomsday argument, so that the chance of a disaster is only what one would ordinarily estimate. (shrink)

In a recent paper in this journal, Ken Olum attempts to refute the doomsday argument by appealing to the self–indication assumption (SIA) that your very existence gives you reason to think that there are many observers. Unlike earlier users of this strategy, Olum tries to counter objections that have been made against (SIA). We argue that his defence of (SIA) is unsuccessful. This does not, however, mean that one has to accept the doomsday argument (or the other counter–intuitive (...) results that flow from related thought–experiments). A developed theory of observation selection effects shows why the doomsday argument is inconclusive, and how one can consistently reject both it and (SIA). (shrink)

In a recent article, John Leslie has defended the intriguing Carter-Leslie ‘Doomsday Argument’ (Philosophy, January 2000). I argue that an essential presupposition of the argument—that ‘the case of one's name coming out of [an] urn is sufficiently similar to the case of being born into the world’—engenders, in turn, a parallel ‘Ussherian Corollary’. The dubiousness of this Corollary, coupled with independent considerations, casts doubt upon the Carter-Leslie presupposition, and hence, dooms the Doomsday argument.

In a recent paper in this journal, Ken Olum attempts to refute the Doomsday argument by appealing to the self-indication assumption, the idea that your very existence gives you reason to think that there are many observers. In contrast to earlier refutation attempts that use this strategy, Olum confronts and try to counter some of the objections that have been made against SIA. We argue that his defense of SIA is unsuccessful. This does not, however, mean that one has (...) to accept the Doomsday argument. A developed theory of observation selection effects shows why the Doomsday argument is inconclusive and how one can consistently reject both it and SIA. (shrink)

A recent paper by Korb and Oliver in this journal attempts to refute the Carter-Leslie Doomsday argument. I organize their remarks into five objections and show that they all fail. Further efforts are thus called upon to find out what, if anything, is wrong with Carter and Leslie's disturbing reasoning. While ultimately unsuccessful, Korb and Oliver's objections do however in some instances force us to become clearer about what the Doomsday argument does and doesn't imply.

We give an analysis of the Monty Hall problem purely in terms of confirmation, without making any lottery assumptions about priors. Along the way, we show the Monty Hall problem is structurally identical to the Doomsday Argument.

Sound propagation within certain non-relativistic condensed matter models obeys a relativistic wave equation despite such systems admitting entirely non-relativistic descriptions. A natural question that arises upon consideration of this is, “do devices exist that will experience the relativity in these systems?” We describe a thought experiment in which ‘acoustic observers’ possess devices called sound clocks that can be connected to form chains. Careful investigation shows that appropriately constructed chains of stationary and moving sound clocks are perceived by observers on the (...) other chain as undergoing the relativistic phenomena of length contraction and time dilation by the Lorentz factor, \, with \ the speed of sound. Sound clocks within moving chains actually tick less frequently than stationary ones and must be separated by a shorter distance than when stationary to satisfy simultaneity conditions. Stationary sound clocks appear to be length contracted and time dilated to moving observers due to their misunderstanding of their own state of motion with respect to the laboratory. Observers restricted to using sound clocks describe a universe kinematically consistent with the theory of special relativity, despite the preferred frame of their universe in the laboratory. Such devices show promise in further probing analogue relativity models, for example in investigating phenomena that require careful consideration of the proper time elapsed for observers. (shrink)

The Doomsday Argument says we should increase our subjective probability that Doomsday will occur once we take into account how many humans have lived before us. One objection to this conclusion is that we should accept the Self-Indication Assumption (SIA): Given the fact that you exist, you should (other things equal) favor hypotheses according to which many observers exist over hypotheses on which few observers exist. Nick Bostrom argues that we should not accept the SIA, because it can (...) be used without knowledge of birth rank. Bradley Monton tries to construct a Doomsday Argument without knowledge of birth rank. I argue that Monton fails. The argument he constructs has implicit knowledge of birth rank and it is this knowledge that does the work. Furthermore, I argue that provided we dont have certain specific information about the future, the Doomsday Argument requires knowledge of birth rank. (shrink)

Recent work in the physics literature demonstrates that, in particular classes of rotating spacetimes, physical light rays in general do not traverse null geodesics. Having presented this result, we discuss its philosophical significance, both for the clock hypothesis (and, in particular, a recent purported proof thereof for light clocks), and for the operational meaning of the metric field. 1Introduction 2Fletcher's Theorem 2.1Maudlin on the clock hypothesis in special relativity 2.2Fletcher’s result in special relativity 2.3Fletcher’s theorem in general relativity (...) 3Electromagnetism and the Geometrical-Optical Limit 3.1Maxwell’s equations in curved spacetime 3.2The geometrical-optical limit 3.3Rotating spacetimes 3.4Aren’t Gödel spacetimes unphysical? 4The Clock Hypothesis and Chronogeometry 4.1Natural and mathematical observations 4.2Clock registry discord 4.3Chronogeometry 5Conclusion. (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.

Leslie’s doomsday argument purports to show that the likelihood of the human race perishing soon is greater than we think. The probability we attach to it, based on our estimate of the chance of various calamities which might bring extinction about (a nuclear holocaust, an ecological disaster, etc.), should be adjusted as follows. If the human race were to survive for a long time, we, livingnow, would be atypical. So our living now increases the probability that the human race (...) will end shortly. In this paper, I criticize some attempts to rebut the argument, and present my own. To facilitate the analysis, I consider a structurally similar problem, the “ShootingRoom.”. (shrink)

If the most familiar overlapping interpretation of Everettian quantum mechanics is correct, then each of us is constantly splitting into multiple people. This consequence gives rise to the quantum doomsday argument, which threatens to draw crippling epistemic consequences from EQM. However, a diverging interpretation of EQM undermines the quantum doomsday argument completely. This appears to tell in favour of the diverging interpretation. But it is surprising that a metaphysical question that is apparently underdetermined by the physics should be (...) settled by purely epistemological considerations; and I argue that the positive case for divergence based on the quantum doomsday effect is ultimately unsuccessful. I discuss how some influential treatments of Everettian confirmation handle the quantum doomsday puzzle, and suggest that it can most satisfyingly be resolved via a naturalistic approach to the metaphysics of modality. (shrink)

The clock hypothesis is taken to be an assumption independent of special relativity necessary to describe accelerated clocks. This enables to equate the time read off by a clock to the proper time. Here, it is considered a physical system–the light clock–proposed by Marzke and Wheeler. Recently, Fletcher proved a theorem that shows that a sufficiently small light clock has a time reading that approximates to an arbitrary degree the proper time. The clock hypothesis is (...) not necessary to arrive at this result. Here, one explores the consequences of this regarding the status of the clock hypothesis. (shrink)

Daylight is the primary cue used by circadian clocks to entrain to the day/night cycle so as to synchronize physiological processes with periodic environmental changes induced by Earth rotation.However, the temporal daylight pattern is not the same every day due to erratic weather fluctuations or regular seasonal changes. Then, how do circadian clocks operate properly in varying weather and seasons? In this paper, we discuss the strategy unveiled by recent studies of the circadian clock of Ostreococcus tauri, the smallest (...) free‐living eukaryotic organism. It combines mechanisms controlling light inputs and clock sensitivity, shaping both the dynamics of the core circadian oscillator and its forcing by light so as to ensure stable and precise synchronization in all weather and seasons.Editor's suggested further reading in BioEssays: Another place, another timer: Marine species and the rhythms of life Abstract. (shrink)

A recent paper by Korb and Oliver in this journal attempts to refute the Carter-Leslie Doomsday argument. I organize their remarks into five objections and show that they all fail. Further efforts are thus called upon to find out what, if anything, is wrong with Carter and Leslie’s disturbing reasoning. While ultimately unsuccessful, Korb and Oliver’s objections do however in some instances force us to become clearer about what the Doomsday argument does and doesn’t imply.

1. Introduction. The germ of the clock paradox was contained in Einstein's fundamental paper on the special theory of relativity, where he declares that the retardation of a moving clock “still holds good if the clock moves from A to B in any polygonal line, and also when the points A and B coincide.” This remark soon gave rise to a criticism which was to play a prominent role in the discussions of the consistency of the theory (...) of relativity. It was charged that this theory allows the paradoxical conclusion that at the instant of the return of a moving clock U1 to its point of departure A, the time shown by Ul is both earlier and later than the corresponding reading of a clock U2 which has remained stationary at A during U1's journey. Critics based this contention on the following assumptions, for which they claimed the sanction of relativity: The relative motion of U1 and U2 is such that the kinematic process seen by an observer on one of these clocks is of the same character as that seen by an observer on the other, and this symmetry allows each of these two clocks to be used as a reference frame from which to describe the motion of the other, and there is reciprocity between these two reference frames such that in each of them, the moving clock must be slow upon returning to the stationary one. (shrink)

I present a new case in which the Doomsday Argument runs afoul of epistemic intuition much more strongly than before. This leads to a dilemma: in the new case either DA is committed to unacceptable counterintuitiveness and belief in miracles, or else it is irrelevant. I then explore under what conditions DA can escape this dilemma. The discussion turns on several issues that have not been much emphasised in previous work on DA: a concern that I label trumping; the (...) degree of uncertainty about relevant probability estimates; and the exact sequence in which we integrate DA and empirical concerns. I conclude that only given a particular configuration of these factors might DA still be of interest. (shrink)

It is the prevailing paradigm in contemporary physics to model the dynamical evolution of physical systems in terms of a real parameter conventionally denoted as 't' ('little tee'). We typically call such dynamical models laws of nature' and t we call 'physical time'. It is common in the philosophy of time to regard t as time itself, and to take the global structure of general relativity as the ultimate guide to physical time, and so consequently the true nature of time. (...) In this paper we defend the idea that physical time, t, is rather better defined as an operational modelling parameter: we measure relations between changing physical quantities using bespoke physical systems---i.e. clocks---that coordinate local coincidences. We argue that the sorts of physical systems that make good clocks---what we call precision clocks---are those that exhibit self-sustained oscillations known as limit cycles, which are ubiquitous in open, driven, stable, dissipative systems. We develop the physical and philosophical ramifications of this conception of physical time, particularly the notion that physical time does not track something 'out there' in the world. As a result, we speculate that physical time is perhaps not as different from manifest time as many philosophers of time (and apparently general relativity) seem to suggest. (shrink)

Across a wide range of cultural forms, including philosophy, cultural theory, literature and art, the figure of the clock has drawn suspicion, censure and outright hostility. In contrast, even while maps have been shown to be complicit with forms of domination, they are also widely recognised as tools that can be critically reworked in the service of more liberatory ends. This paper seeks to counteract the tendency to see clocks in this way, arguing that they have many more interesting (...) possibilities than they are usually given credit for. An analysis of approaches to clocks in continental philosophy critiques the way they have too often been dismissed as unworthy of further analysis, and argues that this dismissal is based upon an inadequate understanding of how clocks operate. Seeking to move towards more critical and curious approaches, the paper draws inspiration from critical cartography in order to call for the development of a ‘critical horology’ which would emphasise both the fundamentally political nature of clocks, and the potential for designing them otherwise. A discussion of temporal design provides a range of examples of how clocks might open up new horizons within the politics of time. (shrink)

A refutation of the doomsday argument is offered. Through a simple thought experiment analysed in Bayesian terms the fallacy is shown to be the assumption that a currently living person represents a random sample from the population of all persons who will ever have existed. A more general version of the counter argument is then given. Previous arguments that purport to answer this concern are also addressed. One result is determining criteria for the applicability of time sampling arguments, i.e., (...) under what conditions can a specific instant in time be regarded as a random sample from a time span. Given this new understanding, the incredible consequences of the doomsday and related arguments evaporate. (shrink)

In her articles on the clock paradox and the relativity of time Luise Lange defends the theory of relativity against philosophical refutations, by showing that the apparent clock paradox is not a paradox, but merely conflicts with common sense and is based on a misunderstanding of the theory. The following study explores, contextualizes and analyzes Lange’s clear and sophisticated contribution to the debate on the clock paradox for the first time.

In the eighteenth century, the sciences and their applications adopted a new attitude based on quantification and, increasingly, on a notion of precision. Within this process, instruments played a significant role. However, while new devices such as the micrometer, telescope, and pendulum clock embodied a formerly unknown potential of precision, this could only be realized by defining a set of practices regulating their application and control. The paper picks up the case of pendulum clocks used in eighteenth-century observatories in (...) order to show the process of learning in the course of which the pendulum clock first became a precision instrument. By examining the results of an especially developed statistical analysis, conducted to compare the performance of eighteenth-century clocks, it highlights the diversity of conditions, attitudes, and manners of handling that are characteristic for the epoch. In this way, it underlines the necessity of standardization of timekeeping practices rather than exclusively focusing on the technological development of clocks. Ultimately, the paper discusses the role of makers and users in order to show the evolution of a “precision instrument.”. (shrink)

In her articles on the clock paradox and the relativity of time Luise Lange (1891–1978) defends the theory of relativity against philosophical refutations, by showing that the apparent clock paradox is not a paradox, but merely conflicts with common sense and is based on a misunderstanding of the theory. The following study explores, contextualizes and analyzes Lange’s clear and sophisticated contribution to the debate on the clock paradox for the first time.

Recent work in the physics literature demonstrates that, in particular classes of rotating spacetimes, physical light rays in general do not traverse null geodesics. Having presented this result, we discuss its philosophical significance, both for the clock hypothesis, and for the operational meaning of the metric field.

Rarely does philosophy produce empirical predictions. The Doomsday argument is an important exception. From seemingly trivial premises it seeks to show that the risk that humankind will go extinct soon has been systematically underestimated. Nearly everybody's first reaction is that there must be something wrong with such an argument. Yet despite being subjected to intense scrutiny by a growing number of philosophers, no simple flaw in the argument has been identified.

Einstein’s equivalence principle has a number of problems, and it is often applied incorrectly. Clocks on the earth do not seem to be affected by the sun’s gravitational potential. The most commonly accepted reason given is a faulty application of the equivalence principle. While no valid reason is available within either the special or general theories of relativity, ether theories can provide a valid explanation. A clock bias of the correct magnitude and position dependence can convert the Selleri transformation (...) of ether theories into an apparent Lorentz transformation, which gives rise to an apparent equivalence of inertial frames. The results indicate that the special theory is invalid and that only an apparent relativity exists. (shrink)

Objective: Clock variance is an important statistic in many clinical and developmental studies. Existing methods require a large number of trials for accurate clock variability assessment, which is problematic in studies using clinical or either young or aged participants. Furthermore, these existing methods often implicitly convolute clock and memory processes, making it difficult to disentangle whether the clock or memory system are driving the observed deviations. Here we assessed whether twenty repeated productions of a well-engrained interval (...) (1 second), a task that does not incorporate memory updating nor the processing of feedback, could provide an accurate assessment of clock variability. Method: Sixty-eight undergraduate students completed two tasks: a 1-second production task in which they were asked to produce a 1-second duration by ending a tone by a keypress, and a multi-duration reproduction task. Durations presented in the reproduction task were tones lasting 1.17, 1.4 and 1.68 seconds. No feedback was presented in either task, and the order of presentation was counterbalanced between participants. Results: The observed central tendency in the reproduction task was better explained by models including the measures of clock variability derived from the 1-second production task than by models without it. Three clock variability measures were calculated for each participant (standard deviation, root mean squared residuals (RMSR) from an estimated linear slope, and RMSR scaled by mean production duration). The model including the scaled RMSR was prefered over the alternative models, and no notable effects of the order of presentation were observed. These results suggest that (1) measures of variability should account for drift, (2) the presentation of another timing task before a 1-second production task did not influence the assessment of the clock variability, and (3) the observed variability adheres to the scalar property and predicts temporal performance, and is thus a usable index of clock variability. Conclusion: This study shows that just 20 repeated productions of 1 second provide a reliable index of clock variability. As administering this task is fast and easy, it could prove to be useful in a large variety of developmental and clinical populations. (shrink)