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)

When addressing the notion of proper time in the theory of relativity, it is usually taken for granted that the time read by an accelerated clock is given by the Minkowski proper time. However, there are authors like Harvey Brown that consider necessary an extra assumption to arrive at this result, the so-called clock hypothesis. In opposition to Brown, Richard TW Arthur takes the clock hypothesis to be already implicit in the theory. In this paper (...) I will present a view different from these authors by taking into account Einstein’s notion of natural clock and showing its relevance to the debate. (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 (...) class='Hi'>hypothesis is not necessary to arrive at this result. Here, one explores the consequences of this regarding the status of the clock hypothesis. (shrink)

In 1955, Norbert Wiener suggested a sociological model according to which all forms of culture ultimately depended on the temporal coordination of human activities, in particular their synchronization. The basis for Wiener’s model was provided by his insights into the temporal structures of cerebral processes. This article reconstructs the historical context of Wiener’s ‘brain clock’ hypothesis, largely via his dialogues with John W. Stroud and other scholars working at the intersection of neurophysiology, experimental psychology, and electrical engineering. Since (...) the 19th century, physiologists and psychologists have been conducting experimental investigations into the relation between time and the brain. Using innovative instruments and technologies, Stroud rehearsed these experiments, in part without paying any attention at all to the experimental traditions involved. Against this background, this article argues that the novelty of Wiener’s model relies largely on his productive rephrasing of physiological and psychological findings that had been established long before the Second World War. (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 for the operational meaning of the metric field.

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)

In a recent paper in this journal which was part of a panel discussion of Grünbaum's philosophy of science, M. G. Evans discusses the Lorentz-Fitzgerald contraction hypothesis and related matters [2]. The purpose of this note is to clarify and correct some of the points in Evans' paper.

I look at the ‘flavour-oscillation clocks’ proposed by D. V. Ahluwalia and two of his arguments suggesting that such clocks might behave in a way that threatens the geometricity of general relativity (GR). The first argument states that the behaviour of these clocks in the vicinity of a rotating gravitational source implies a non-geometrical element of gravity. I argue that the phenomenon is best seen as an instance of violation of the ‘clock hypothesis’ and therefore does not threaten (...) the geometrical nature of gravitation. Ahluwalia’s second argument, for the ‘incompleteness’ of general relativity, involves the idea that flavour-oscillation clocks can detect constant gravitational potentials. I argue that the purported ‘incompleteness-establishing’ result is in fact one that applies to all clocks. It is entirely derivable from general relativity, does not result in the observability of the potential, and is not at odds with any of general relativity’s foundations. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Leibniz and the Two ClocksDavid ScottAnyone familiar with Leibniz’s philosophy in general and with his critique of occasionalism in particular is likely familiar with his example of two clocks. Generally speaking, the example illustrates a range of hypotheses that, according to Leibniz, might possibly explain the connections between substances in the world. The most important of these hypotheses are Leibniz’s own doctrine of the preestablished harmony and the occasionalist—for (...) present purposes, Malebranche’s—doctrine of causation. In Leibniz’s mind at least, the two clocks example (so-called because substances are represented by two clocks) illustrates the superiority of the hypothesis of the preestablished harmony over occasionalism. Whether the example in fact succeeds in this regard is the primary question of this paper.Given the times, Leibniz’s choice of example is understandable. A clock is ideally suited to represent a mechanism, of course; and in view of the general “mechanization of the world view” of that time, the example seems to have been in the air.1 Spring-driven clocks had appeared at the outset of the sixteenth century, and the kind of clock Leibniz seems to have in mind in his example, namely, one driven by a pendulum, was the invention, in about 1656, of Christian Huygens, who was a significant influence on Leibniz. Huygens’s invention in fact provided the impetus for a broadening of the importance and extent of horology.2Although Leibniz’s choice of example was understandable, it was not a happy one, and the general importunity of his use of this example was [End Page 445] recognized by both his contemporary critics and his subsequent commentators.3 In fact his choice of the example becomes almost ironic when it is recalled that Geulincx, who is most commonly associated with the example, was an occasionalist. The operations of two clocks, between which there is a constant and fixed relation, say, of keeping the same time, cannot normally be said to be “related.” The example is more intuitively taken to indicate the random, accidental, unnecessary, and unconnected nature of the otherwise constant and regular relation between the clocks; and so one would think the example more suited to an occasionalist’s position than to that of Leibniz.In what follows I aim to judge the effectiveness—in Leibniz’s own terms—of the two clocks example. In gauging the effectiveness of Leibniz’s use of the example, I expect that a few things can be learned about Leibniz’s system in general and about his critique of occasionalism in particular. My procedure will be to examine separately what I take to be four significant occasions in which Leibniz compares things or substances in the world and clocks. The passages in question date from a period spanning ten years, and in each instance the example is put to service in Leibniz’s attempt to better occasionalism.Beyond this, although the comparison is employed or appraised in slightly different ways each time, the uses to which it is put are basically two. In the first two instances examined below, it is employed primarily to distinguish the preestablished harmony from occasionalism. I will be arguing that, to the extent that it fails to illustrate his point, Leibniz fails adequately to distinguish these two doctrines. This was Arnauld’s criticism.4 In the third and fourth instances, however, the example is employed solely to illustrate certain features of the preestablished harmony. On my analysis, it does not appear to fulfill this role either. [End Page 446]First Use of the ExampleOne of the more well known statements of the two clocks example is from an explanation Leibniz gives to Basnage de Beauval in 1696 of his “New System” (1695):Imagine two clocks or watches which are in perfect agreement. Now this can happen in three ways. The first is that of a natural influence.... The second way of making two clocks, even poor ones, agree is always to assign a skilled craftsman to them who adjusts them and constantly sets them in agreement. The third way is to construct these two timepieces at the beginning with such skill and accuracy that one can... (shrink)

In this paper I discuss the concept of time in physics. I consider the thermal time hypothesis and I claim that thermal clocks and atomic clocks measure different physical times, whereby thermal time and relativistic time are not compatible with each other. This hypothesis opens the possibility of a new foundation of the theory of physical time, and new perspectives in theoretical and philosophical researches.

Textile is one of the largest export and source of foreign exchange in Pakistan. For the last two decades, Textile sector is serving as the backbone for Pakistan economy. Several foreign retailers including Target, Jessie Penny, Wal-Mart, and Kohl’s are outsourcing textile and garments from Pakistan. Along with the quality, these retailers are highly concerned with the ethical and social issues of their suppliers, including child labor, forced labor, compensation, working hours and environment health, and safety. My current study is (...) an applied research, based on the problem, regarding the working hours and its proper management in textile factories, mismanagement of which lead to serious issues during social and ethical standard audits. Repetition of which may consequent in termination of business with suppliers and factories. The research hypothesis is that working off the clock will lead to overtime premium not paid and double book record keeping. As far as ethical and social compliance is concerned both overtime premiums not paid and double book records are critical issues during SC audit. A sample of 40 suppliers of Pakistan was randomly selected working with foreign buyers. Secondary data were used to verify the findings based on Audits finding conducted by different third party during a period of 2 years, i.e. Feb., 2010 to Jan., 2012. The results and research findings reflect that during the last 2 years out of 40 factories audit reports 25 factories were found having working off the clock that also lead to overtime premium not paid. However, double book records were not witnessed in all 40 factories SC audit reports as parallel records were not maintained by any factories. The above findings will help the suppliers, factories, and buyers to develop a proactive approach and proper production planning to avoid critical issues and smooth business activities. (shrink)

The molecular clock hypothesis remains controversial more than a quarter of a century after it was first proposed. A variety of approaches have been applied to testing the molecular clock in mammals. In many of these studies apparent refutation of the molecular clock has based on false assumptions about the pattern of mammalian evolution. With a few exceptions there now appears to be little evidence for variation in the rate of molecular evolution among mammalian lineages, although (...) comparison of more genes and proteins among a greater variety of mammalian orders is needed before a definitive conclusion can be reached on the issue. (shrink)

The particle internal clock conjectured by de Broglie in 1924 was investigated in a channeling experiment using a beam of ∼80 MeV electrons aligned along the 〈110〉 direction of a 1 μm thick silicon crystal. Some of the electrons undergo a rosette motion, in which they interact with a single atomic row. When the electron energy is finely varied, the rate of electron transmission at 0° shows a 8% dip within 0.5% of the resonance energy, 80.874 MeV, for which (...) the frequency of atomic collisions matches the electron’s internal clock frequency. A model is presented to show the compatibility of our data with the de Broglie hypothesis. (shrink)

The Whorfian hypothesis has received support from recent findings in psychology, linguistics, and anthropology. This evidence has been interpreted as supporting the view that language modulates all stages of perception and cognition, in accordance with Whorf’s original proposal. In light of a much broader body of evidence on time perception, I propose to evaluate these findings with respect to their scope. When assessed collectively, the entire body of evidence on time perception shows that the Whorfian hypothesis has a (...) limited scope and that it does not affect early stages of time perception. In particular, all the available evidence shows that the scope of language modulation is limited in the case of time perception, and that the most important mechanisms for time perception are cognitive clocks and simultaneity windows, which we use to perceive the temporal properties of events. Language modulation has distorting effects, but only at later stages of processing or with respect to specific categorization tasks. The paper explains what is the role of these effects in the context of all the available evidence on time cognition and perception. (shrink)

In the first parts of this study on the concept of the biological clock it has been investigated how it is used in the field of biorhythmology. The analysis of the contents of the concept is preceded by a survey of the current research in this field.There are two general hypotheses with respect to the ultimate origin of rhythmic phenomena: the Endogenous Timer Hypothesis and the Exogenous Timer Hypothesis. Within the Endogenous Timer Hypothesis two contrasting viewpoints (...) with respect to the structure of the biological clock can be distinguished, which have been called: the Discrete Entity view, and the Organizational view.It has been shown that in the application of the general clock-idea upon the organism a logical distortion is present. The organism is conceived tobe a clock and tohave a clock simultaneously.In anticipation of the analysis of the explanatory value of the concept of the biological clock in part II, it has been put forward that in a number of cases time-measurement can be considered as a superfluous element in the explanation of the phenomena involved.Finally it has been demonstrated that in the case of the Exogenous Timer Hypothesis the concept of the biological clock is not relevant. The Exogenous Timer Hypothesis has been compared with the Endogenous Timer Hypothesis with respect to the criterion of the principle of parsimony, orOccam's razor. (shrink)

The Fitzgerald-Lorentz contraction hypothesis, proposed as an explanation of the Michelson-Morley result, fails to account for the Kennedy-Thorndike result. Hence, Grünbaum argues, the hypothesis has been falsified. However, the contraction hypothesis as formulated by Lorentz is false for the very fundamental reason that it entails a contradiction, namely, the consequence that light waves must have a variable velocity along what by definition is taken to be a rest length. Furthermore, the attempt to resolve this contradiction by coupling (...) the Fitzgerald-Lorentz contraction with the hypothesis that clock rates are a function of velocity, is open to a sound, methodological objection. The Michelson-Morley result is fully satisfied, provided only that the lengths of the interferometer arms, in the longitudinal and transverse positions, are thought to be related to one another in a certain ratio, and this ratio may be interpreted as a contraction in both arms. Since this twofold contraction hypothesis suffices to explain both the Michelson-Morley and the Kennedy-Thorndike results, and since it entails no contradiction, there is no need to correct both the length of rods and the rate of clocks. Therefore, the combined clock-rod hypothesis, and with it the Fitzgerald-Lorentz contraction hypothesis, must be rejected. (shrink)

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)

In this paper I try to sort out a tangle of issues regarding time, inertia, proper time and the so-called “clock hypothesis” raised by Harvey Brown's discussion of them in his recent book, Physical Relativity. I attempt to clarify the connection between time and inertia, as well as the deficiencies in Newton's “derivation” of Corollary 5, by giving a group theoretic treatment original with J.-P. Provost. This shows how both the Galilei and Lorentz transformations may be derived from (...) the relativity principle on the basis of certain elementary assumptions regarding time. I then reflect on the implications of this derivation for understanding proper time and the clock hypothesis. (shrink)

The differential aging effect is shown to be valid in any physically reasonable extension of the special theory of relativity which includes a description of accelerating observers. Einstein's controversial assumption—the clock hypothesis—is avoided. Instead, it is sufficient to assume accessibility—that it is possible to travel from one inertial observer to another and then return to the first in a reasonable manner. Since Minkowski space-time displays this accessibility property, there must be an error in Sachs's quaternion development of general (...) relativity. No assumptions concerning measurements—proper time—of accelerating observers are necessary, nor are assumptions concerning special features of their motion—uniform acceleration. (shrink)

Many philosophers believe that there is a causal condition on perception, and that this condition is a conceptual truth about perception. A highly influential argument for this claim is based on intuitive responses to Gricean style thought experiments. Do the folk share the intuitions of philosophers? Roberts et al. (2016) presented participants with two kinds of cases: Blocker cases (similar to Grice’s case involving a mirror and a pillar) and Non-Blocker cases (similar to Grice’s case involving a clock and (...) brain stimulation). They found that a substantial minority agreed that seeing occurs in the Non-Blocker cases, and that in the Blocker cases significantly less agreed that seeing occurs. They thus hypothesized that folk intuitions better align with a no blocker condition than with a causal condition. This paper continues this line of enquiry with two new experiments. The paper investigates the generality and robustness of Roberts et al.’s findings by expanding the sense modalities tested from only vision to audition and olfaction as well. The paper also uses Gricean style thought experiments as a case study for investigating the “reflection defense” against the negative project in experimental philosophy. Our results replicate and extend Roberts et al.’s study and support their hypothesis that folk intuitions better align with a no blocker condition. They also provide an empirical reason to doubt the reflection defense. (shrink)

One of the goals of physiologists who study the detailed physical, chemical,and neurological mechanisms operating within the human body is to understand the intricate causal processes which underlie human abilities and activities. It is doubtless premature to predict that they will eventually be able to explain the behaviour of a particular human being as we might now explain the behaviour of a pendulum clock or even the invisible changes occurring within the hardware of a modern electronic computer. Nonetheless, it (...) seems fair to say that hovering in the background of investigations into human physiology is the promise or threat, depending upon how one looks at the matter that human beings are complete physical-chemical systems and that all events taking place within their bodies and all movements of their bodies could be accounted for by physical causes if we but knew enough. I am not concerned at the moment with whether or not this ’mechanistic’ hypothesis is true, assuming that it is clear enough to be intelligible, nor with whether or not we could ever know that it is true. I wish to consider the somewhat more accessible yet equally important question whether our coming to believe that the hypothesis is true would warrant our relinquishing our conception of ourselves as beings who are capable of acting for reasons to achieve ends of our own choosing. I use the word ’warrant’ to indicate that I will not be discussing the possibility that believing the mechanistic hypothesis might lead us, as a matter of psychological fact, to think of human beings as mere automata, as objects whose movements are to be explained only by causes rather than by reasons, as are the actions of a personal subject. I intend to consider only whether the acceptance of mechanism would in fact justify such a change in conception. (shrink)

The time marked by the clock hands, the so-called “objective time,” is deeply different from the one perceived by the individual. Starting from this hypothesis, directly connected to the subjective modality of “living” the time and defined as time perspective, we will try to understand how much it affects the various domains of people's lives, attitudes, and experiences. Therefore, the research investigates whether all our decisions can be influenced by one or more time perspectives beyond our awareness. Last, (...) but not least, we will try to understand if some time perspectives in specific contexts are more functional and adaptive than others. (shrink)

Contrary to dictionaries, a non sequitur isn’t “any statement that doesn’t follow logically from previous statements”. Otherwise, every opening statement would be a non sequitur: a non sequitur is a statement claimed to follow from previous statements but that doesn’t follow. If the sentence making a given statement doesn’t contain ‘thus’, ‘so’, ‘hence’, ‘therefore’, or something else indicating an implication claim, the statement isn’t a non sequitur in this sense. But this is only one of several senses of that expression, (...) which, contrary to appearances, is a unitary common noun more properly written as one word: non-sequitur or nonsequitur. Above a nonsequitur was, roughly speaking, a conclusion of an invalid premise- conclusion argument, but not every such, only those that were stated to follow from premises that had been stated. Every informative proposition is the conclusion of an invalid argument. Anyway, nonsequiturs were not arguments. However, the expression ‘nonsequitur’ also means “invalid premise- conclusion argument”. It also means something like “fallacious reasoning” as in ‘Abe’s proof of the big-bang hypothesis is a nonsequitur’. The English noun is also used for an irrelevancy, an abrupt change of topic, or for any of many other expressions that are gratuitous, inappropriate, incongruous, or in some other way out of place. The English noun is derived from the Latin expression ‘non sequitur’, which is not a common noun but a sentence variously meaning “it isn’t in sequence ”, “it doesn’t follow”, “it is out of order”, etc. A statement that begins ‘in the second place’ is a nonsequitur if the previous sentence lacked implication of something like ‘in the first place’ or if it contained something similar to ‘in the third place’. In fact, a true implication claim can be a nonsequitur if there is no reason for making it. If Ben says ‘Hence, Abe swims and Abe swims’ in reply to Carl’s statement ‘Abe swims‘, then Ben may well be committing a nonsequitur. Many conversation stoppers are nonsequiturs. This lecture surveys and analyses a wide selection of uses of ‘nonsequitur’ in logic and logic-related literature. -/- END OF DRAFT 4 -/- NOTE 091215: When Rick Perry was discussing possible withdrawal from the race—unfortunately not the human race but the Republican race—a reporter reminded him that just last week Donald Trump predicted the Perry withdrawal. Perry interrupted with “A broken clock is right once a day”. -/- If you did not know Perry you might think his reply was a brilliant diversionary nonsequitur. If you know Perry you might think his reply was a stupid nonsequitur. -/- For the record, he did say ‘once a day’, not ‘twice a day’. BTW, my interjection ‘unfortunately not the human race but the Republican race’ was also a nonsequitur. (shrink)

Many philosophers believe that there is a causal condition on perception, and that this condition is a conceptual truth about perception. A highly influential argument for this claim is based on intuitive responses to Gricean-style thought experiments. Do the folk share the intuitions of philosophers? Roberts et al. (2016) presented participants with two kinds of cases: Blocker cases (similar to Grice’s case involving a mirror and a pillar) and Non-Blocker cases (similar to Grice’s case involving a clock and brain (...) stimulation). They found that a substantial minority agreed that seeing occurs in the Non-Blocker cases, and that in the Blocker cases significantly less agreed that seeing occurs. They thus hypothesized that folk intuitions better align with a no blocker condition than with a causal condition. This paper continues this line of enquiry with two new experiments. The paper investigates the generality and robustness of Roberts et al.’s findings by expanding the sense modalities tested from only vision to audition and olfaction as well. The paper also uses Gricean-style thought experiments as a case study for investigating the “reflection defense” against the negative project in experimental philosophy. Our results replicate and extend Roberts et al.’s study and support their hypothesis that folk intuitions better align with a no blocker condition. They also provide an empirical reason to doubt the reflection defense. (shrink)

Research on sleep loss and vigilance both focus on declines in cognitive performance, but theoretical accounts have developed largely in parallel in these two areas. In addition, computational instantiations of theoretical accounts are rare. The current work uses computational modeling to explore whether the same mechanisms can account for the effects of both sleep loss and time on task on performance. A classic task used in the sleep deprivation literature, the Psychomotor Vigilance Test, was extended from the typical 10-min duration (...) to 35 min, to make the task similar in duration to traditional vigilance tasks. A computational cognitive model demonstrated that the effects of time on task in the PVT were equivalent to those observed with sleep loss. Subsequently, the same mechanisms were applied to a more traditional vigilance task—the Mackworth Clock Task—providing a good fit to existing data. This supports the hypothesis that these different types of fatigue may produce functionally equivalent declines in performance. (shrink)

Saccadic chronostasis refers to the subjective temporal lengthening of the first visual stimulus perceived after an eye movement. It has been quantified using a duration discrimination task. Most models of human duration discrimination hypothesise an internal clock. These models could explain chronostasis as a transient increase in internal clock speed due to arousal following a saccade, leading to temporal overestimation. Two experiments are described which addressed this hypothesis by parametrically varying the duration of the stimuli that are (...) being judged. Changes in internal clock speed predict chronostasis effects proportional to stimulus duration. No evidence for proportionality was found. Two further experiments assessed the appropriateness of the control conditions employed. Results indicated that the chronostasis effect is constant across a wide range of stimulus durations and does not reflect the pattern of visual stimulation experienced during a saccade, suggesting that arousal is not critical. Instead, alternative processes, such as one affecting the onset of timing are implicated. Further research is required to select between these alternatives. (shrink)

Experiments with the simple pendulum are easy, but its motion is nevertheless confounded with simple harmonic motion. However, refined theoretical models of the pendulum can, today, be easily taught using software like CALCODE. Similarly, the cycloidal pendulum is isochronous only in simplified theory. But what are theoretically equal intervals of time? Newton accepted Barrow’s even tenor hypothesis, but conceded that ‘equal motions’ did not exist – the refutability of Newtonian physics is independent of time measurement. However, time measurement was (...) the key difficulty in reconciling Newtonian physics with electrodynamics. On Poincaré’s criterion of convenience, equal intervals of time ought be so defined as to make the enunciation of physics simple. Hence he postulated constancy of the speed of light. (The Michelson–Morley experiment was not critical.) The theory of relativity followed. But does there exist a proper clock? (shrink)

This paper is a comment on both Bunamano and Rovelli (Bridging the neuroscience and physics of time arXiv:2110.01976. (2022)) and Gruber et al. (in Front. Psychol. Hypothesis Theory, 2022) and which discuss the relation between physical time and human time. I claim here, contrary to many views discussed there, that there is no foundational conflict between the way physics views the passage of time and the way the mind/brain perceives it. The problem rather resides in a number of misconceptions (...) leading either to the representation of spacetime as a timeless Block Universe, or at least that physically relevant universe models cannot have preferred spatial sections. The physical expanding universe can be claimed to be an Evolving Block Universe with a time-dependent future boundary, representing the dynamic nature of the way spacetime develops as matter curves spacetime and spacetime tells matter how to move. This context establishes a global direction of time that determines the various local arrows of time. Furthermore time passes when quantum wave function collapse takes place to an eigenstate; during this process, information is lost. The mind/brain acts as an imperfect clock, which coarse-grains the physical passage of time along a world line to determine the experienced passage of time, because neural processes take time to occur. This happens in a contextual way, so experienced time is not linearly related to physical time in general. Finally I point out that the Universe is never infinitely old: its future endpoint always lies infinitely faraway in the future. (shrink)

In this paper, we construct a parallel image of the conventional Maxwell theory by replacing the observer-time by the proper-time of the source. This formulation is mathematically, but not physically, equivalent to the conventional form. The change induces a new symmetry group which is distinct from, but closely related to the Lorentz group, and fixes the clock of the source for all observers. The new wave equation contains an additional term (dissipative), which arises instantaneously with acceleration. This shows that (...) the origin of radiation reaction is not the action of a “charge” on itself but arises from inertial resistance to changes in motion. This dissipative term is equivalent to an effective mass so that classical radiation has both a massless and a massive part. Hence, at the local level the theory is one of particles and fields but there is no self-energy divergence (nor any of the other problems). We also show that, for any closed system of particles, there is a global inertial frame and unique (invariant) global proper-time (for each observer) from which to observe the system. This global clock is intrinsically related to the proper clocks of the individual particles and provides a unique definition of simultaneity for all events associated with the system. We suggest that this clock is the historical clock of Horwitz, Piron, and Fanchi. At this level, the theory is of the action-at-a-distance type and the absorption hypothesis of Wheeler and Feynman follows from global conservation of energy. (shrink)

The heart has a high‐metabolic rate, and its “around‐the‐clock” vital role to sustain life sets it apart in a regenerative setting from other organs and appendages. The landscape of vertebrate species known to perform intrinsic heart regeneration is strongly biased toward ectotherms—for example, fish, salamanders, and embryonic/neonatal ectothermic mammals. It is hypothesized that intrinsic heart regeneration is exclusively limited to the low‐metabolic hearts of ectotherms. The biomedical field of regenerative medicine seeks to devise biologically inspired regenerative therapies to diseased (...) human hearts. Falsification of the ectothermy dependency for heart regeneration hypothesis may be a crucial prerequisite to meaningfully seek inspiration in established ectothermic regenerative animal models. Otherwise, engineering approaches to construct artificial heart components may constitute a more viable path toward regenerative therapies. A more strict definition of regenerative phenomena is generated and several testable sub‐hypotheses and experimental avenues are put forward to elucidate the link between heart regeneration and metabolism. Also see the video abstract here https://youtu.be/fZcanaOT5z8. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Diacritics 31.4 (2001) 85-102 [Access article in PDF] Culture in the Disk Drive Computationalism, Memetics, and the Rise of Posthumanism Stephen Dougherty Ever since Descartes argued that there are striking similarities between a man and a clock, humanism has been in a state of crisis. To put it more pointedly, humanism has always been in a state of crisis, ever since it emerged in the sixteenth and seventeenth (...) centuries as a constellation of beliefs that made man rather than God the measure of all things. Thus, since we are arguably witnesses now to the eclipse of the humanist tradition, we might take some comfort (if any is desired) in considering that if we have failed the ideal of humanism, it has also failed us. From the beginning its borders were too porous, its boundaries too ill defined. For even as man turned himself into a god, he increasingly began to resemble a machine.In terms of bodily representation, our machinic evolution through the last four centuries culminates in the figure of the cyborg; and if we have already become posthuman, as N. Katherine Hayles suggests, then the cyborg stands as the iconic pop culture figure of our epochal transformation. But you don't need electronic prosthetic devices attached to your body or silicon chips implanted in your head to be posthuman. As Hayles argues, "[w]hether or not interventions have been made on the body, new models of subjectivity emerging from such fields as cognitive science and artificial life imply that even a biologically unaltered Homo sapiens counts as posthuman" [4]. What counts especially, according to Hayles, is not the body/machine interface but how we conceptualize the workings of the mind/brain.In the humanist tradition signalled by Descartes, the subject is an I, an ego that is master of itself, a unified consciousness thinking itself. Before it is anything else, the Cartesian subject is a function of thought—ineffable and immaterial, and partaking in its nature of the divine and ineffable spirit that guarantees its communication with the material world. Thus, even though God has always been in the process of disappearing through the centuries since the Renaissance, spirit hasn't. Humanism never abandoned the concept of a spiritualized man, registering at the least a dissatisfaction with science's conventional claim to the possession of special and superior knowledge, and until quite recently dualism of one variety or another has been the normative philosophical attitude.But in posthumanism matters are different. To begin with, as Hayles puts it, "computation rather than possessive individualism is taken as the ground of being" [34]. Human consciousness is no longer that which thinks itself into its own unity, a mysterious phenomenon of infinite reflexivity that would become the central subject of, and the central problem for, modern philosophy. In fact, in the posthumanist regime human consciousness is no longer primarily a matter for philosophy, since questions regarding ontology and epistemology are displaced by the question of functionality. Cognitive processes are turned into syntactical operations similar to those that computers perform, 1 [End Page 85] and consciousness is reduced to mere epiphenomena of those machinic operations. 2Further, the cognitive functions of posthuman subjectivity are dispersed among a complex network of interrelated systems and subsystems (modules) responsible for receiving and interpreting data. 3 Consciousness thus loses the holistic unity it had possessed with a considerable degree of consensus from Descartes up to the behavioralists. Just as significantly, it loses its ineffability. The computationalists do not interrogate the mind as something beyond the grasp of scientific rationality because they do not approach thought as immaterial. Insofar as the brain has become a machine, mind is reduced to matter. In the new posthuman dispensation, then, philosophical dualism gives way to monism.Such an outcome would seem to suggest that the onset of posthumanism represents the ultimate victory for positivism and scientific rationalism in explaining human behavior. As Francis Crick explains in The Astonishing Hypothesis: The Scientific Search for the Soul, "the aim of science is to explain all aspects of the behavior of our brains, including... (shrink)

I address a number of questions concerning the interpretation of local time and the corresponding states theorem (CST) of the Versuch, questions which have been addressed either incompletely or inadequately in the secondary literature. In particular: (1) What is the relation between local time and the behavior of moving clocks? (2) What is the relation between the primed field variables and the electric and magnetic fields in a moving system? (3) What is the relation of the CST to the principle (...) of relativity and requirements of covariance? (4) Does the introduction of local time and the primed field variables constitute a hypothesis, i.e., an addition to or a modification of the basic theory? (shrink)

The genetic equidistance result shows that different species are approximately equidistant to a simpler outgroup in protein sequence similarity, as first reported by Margoliash in 1963. This result, together with those of Zuckerkandl and Pauling in 1962 inspired the molecular clock and in turn the neutral theory of evolution. Here it is shown that the clock/neutral theory had from the beginning overlooked another characteristic of the equidistance result, the overlap feature, which shows a large number of overlapped mutant (...) amino acid positions where any pair of any three species is different provided that the species concerned differ from one another in complexity as a result of macroevolution. In contrast, when simple organisms of similar complexity and short evolutionary divergence are compared, there are only a small number of overlaps largely consistent with chance or the neutral theory. The full reality of the equidistance result strongly supports the Maximum Genetic Diversity hypothesis, a more complete account of hereditary changes. (shrink)

On the basis of the Woodhouse causal axiomatics, we show that conformal proper times and an extra variable in addition to those of space and time, together give a physical justification for the ‘chronometric hypothesis’ of general relativity. Indeed, we show that, with a lack of these latter two ingredients and of this hypothesis, clock paradoxes exist for which the unparadoxical asymmetry cannot be recovered when using the ‘clock and message functions’ only. These proper times originate (...) from a given conformal structure of the spacetime when ascribing different compatible projective structures to each Woodhouse particle, and then, each defines a specific Weylian ‘sheaf structure’. In addition, the proper time parameterizations are defined via path-dependent conformal scale factors, which act like sockets for any kind of physical interaction and also represent the values of the variable associated with the extra dimension. (shrink)

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)

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)

Somites are transient structures which represent the most overt segmental feature of the vertebrate embryo. The strict temporal regulation of somitogenesis is of critical developmental importance since many segmental structures adopt a periodicity based on that of the somites. Until recently, the mechanisms underlying the periodicity of somitogenesis were largely unknown. Based on the oscillations of c-hairy1 and lunatic fringe RNA, we now have evidence for an intrinsic segmentation clock in presomitic cells. Translation of this temporal periodicity into a (...) spatial periodicity, through somite formation, requires Notch signaling. While the Hox genes are certainly involved, it remains unknown how the metameric vertebrate axis becomes regionalized along the antero–posterior (AP) dimension into the occipital, cervical, thoracic, lumbar, and sacral domains. We discuss the implications of cell division as a clock mechanism underlying the regionalization of somites and their derivatives along the AP axis. Possible links between the segmentation clock and axial regionalization are also discussed. (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)

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)

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)

It is generally accepted among philosophers of science that hypothesis testing is a key methodological feature of science. As far as philosophical theories of confirmation are con...

Adrian Heathcote and I agree that a stopped clock does not show—as the adage has it—the right time twice a day, but he thinks, as I do not, that it does show what time it stopped. To think that it does is to treat the position of its hands as evidence of its stopping at the time it did. Add to the justified-true-belief analysis of knowledge the requirement that the evidence on the basis of which the believer is justified (...) be evidence of what is believed in this sense, and you have the long-sought fourth condition to block Gettier cases. I argue that requiring that one’s evidence be evidence in this sense is incompatible with the fallibilism on which Gettier cases are predicated. (shrink)

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)

There are a number of problematic features within the current treatment of time in physical theories, including the “timelessness” of the Universe as encapsulated by the Wheeler–DeWitt equation. This paper considers one particular investigation into resolving this issue; a conditional probability interpretation that was first proposed by Page and Wooters. Those authors addressed the apparent timelessness by subdividing a faux Universe into two entangled parts, “the clock” and “the remainder of the Universe”, and then synchronizing the effective dynamics of (...) the two subsystems by way of conditional probabilities. The current treatment focuses on the possibility of using a realistic clock system; namely, a coherent-state description of a damped harmonic oscillator. This clock proves to be consistent with the conditional probability interpretation; in particular, a standard evolution operator is identified with the position of the clock playing the role of time for the rest of the Universe. Restrictions on the damping factor are determined and, perhaps contrary to expectations, the optimal choice of clock is not necessarily one of minimal damping. (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)