Ever since the now infamous comments made by Hermann Minkowski in 1908 concerning the proper way to view space-time, the debate has raged as to whether or not the universe should be viewed as a four-dimensional, unified whole wherein the past, present, and future are equally real or whether the views espoused by the possibilists, historicists, and presentists regarding the unreality of the future (and, for presentists, the past) are best. Now, a century after Minkowski’s proposed blockworld first sparked debate, (...) we seek a more conclusive argument in favor of the eternalist picture of space-time. Utilizing an argument based on the relativity of simultaneity in the tradition of Putnam and Rietdijk and novel but reasonable assumptions as to the nature of “reality”, we will show that the past, present, and future are equally real, thus ruling out presentism and other theories of time that bestow special ontological status to the past, present, or future as untenable. Finally, we will respond to our critics who would suggest that: 1) there is no metaphysical difference between the positions of eternalism and presentism, 2) the present must be defined as the “here” as well as the “now”, or 3) presentism is correct and our understanding of relativity is incomplete because it does not incorporate a preferred frame. We call eternalist response 1 deflationary since it purports to dissolve or deconstruct the age-old debate between the two views and response 2 compatibilist because it does nothing to alter special relativity (SR) arguing instead that SR unadorned has the resources to save presentism. Response 3 we will call incompatibilism because it adorns SR in some way in order to save presentism a la some sort of preferred frame. We will show that neither move 1 nor 2 can save presentism and move 3 is not well motivated at this juncture except as an ad hoc device to refute eternalism. (shrink)

In this journal, Brogaard and Marlow recently argued that the relativity of simultaneity is an illusion. We claim their argument is fallacious.

In connection with the special theory of relativity, Einstein made use of a now familiar thought experiment1 involving two lightning flashes, a railway train, and an embankment. Whether he used it merely to help explain the theory to others or whether it played a role in the theory's very generation as well is perhaps a matter of conjecture. However, physicist Richard Feynman, for one, believes that Einstein first conceived his theories in the visualizations of thought experiments and developed their (...) mathematical formulations afterwards. According to a recent magazine essay, ‘Einstein came to an understanding about relativity by imagining people going up in elevators and beaming light back and forth between rocket ships. (shrink)

RésuméLe raisonnement selon lequel la simultanéité est relative du point de vue de l'observateur est fondamental dans la Relativité restreinte. Pourtant, l'analyse de ce raisonnement mène aux critiques suivantes:1. Le raisonnement appartient à la physique classique plutǒt qu'à la physique relativiste, en ce qu'il adopte la conception classique de la propagation de la lumière et ignore le principe de la constance de la vitesse de la lumière.2. Il entre en conflit avec l'évidence empirique, car son hypothèse de base et son (...) mode de raisonnement sont presque exactement analogues à ceux qui amenèrent Michelson et Morlay à attendre un résultat positif lors de leur expérience d'interférence.3. Il est logiquement inacceptable, car il repose à la fois sur l'affirmation et sur la négation d'un système de référence privilégié.Bien plus, on montre que l'application correcte des transformations de Lorentz mène non pas à la conclusion que la simultanéité est relative, mais plutǒt à celle qu'elle est absolue.The argument that simultaneity is relative to the viewpoint of an observer, is fundamental to Special Relativity. However, analysis of this argument leads to the following strictures: the argument belongs to classical physics rather than to relativity physics, in that it adheres to the classical view of the propagation of light, and ignores altogether the relativistic principle of the constancy of the velocity of light; the argument conflicts with empirical evidence, in that its basic assumption and mode of reasoning are almost exactly analogous to those which led Michelson and Morley to expect a positive result from their interferometer experiment; the argument is logically untenable, in that it rests on both the affirmation, and the denial, of a privileged frame of reference. Furthermore, it is shown that proper application of the Lorentz transformation, in actually transforming data from one system to another, must lead, not to the conclusion that simultaneity is relative, but rather to the conclusion that it is absolute. (shrink)

In a recent issue of this journal Berit Brogaard and Kristian Marlow claim that an absolute frame of reference is compatible with Einstein’s Special Relativity. To achieve this they tweak Einstein’s famous train and embankment thought experiment and unjustifiably attribute, to Einstein, Hans Reichenbach’s claim that cause and effect are always temporally separated. Their conclusion is incompatible with the proper Lorentz transformations to show how time dilates from one frame of reference to another; transformations they show no evidence of (...) having done. I refute their conclusion by doing the calculations. (shrink)

Some elementary properties of tachyons are described and then it is argued that the claim that (T) Tachyons exist, is incompatible with the truth of the Special Theory of Relativity (STR). First it is argued that from T, STR, and the negation of the principle that (Pl) Effect never precedes cause, one can derive a paradoxical conclusion, one of the so-called "causal paradoxes". An obvious response is to affirm (Pl), but then it is argued that (Pl) and (T) entail (...) that STR is false. (shrink)

Tensism holds that the present moment has a special status that sets it apart from the past and the future, independently of perceivers. One of the main objections to this view has been Einstein’s argument from special relativity, which aims at showing that absolute simultaneity is a myth. We argue that the moving observer in a causal variant of Einstein’s original thought experiment is subject to a temporal illusion. Owing to the analogy of the cases, this casts doubt (...) on the conjectures that there is no privileged frame of reference and that special relativity poses a problem for tensism. (shrink)

It is routinely assumed that Einstein discovered the relativity of simultaneity by thinking about how clocks can be synchronized by light signals, much in accord with the analysis he gave in his 1905 special relativity paper. Yet that is just supposition. We have no real evidence that it actually happened this way. In later recollections, Einstein stressed the importance of several thought experiments in the thinking that led up to the final theory. They include his chasing a (...) light beam thought experiment and his magnet and conductor thought experiment. They do not include thought experiments on clocks and their synchronization. My goal here is to show that other pathways to the relativity of simultaneity are quite plausible. In several places Einstein stressed the importance in his discovery of special relativity of stellar aberration and Fizeau's measurement of the speed of light in moving water. The results can be seen as direct observational expressions of the relativity of simultaneity, if one knows how to read them. I will suggest that, thanks to his knowledge of Lorentz's 1895 Versuch, Einstein did know how to read them, and that it is quite possible that these observations first led Einstein to the relativity of simultaneity. (shrink)

Max Jammer's Concepts of Simultaneity presents a comprehensive, accessible account of the historical development of an important and controversial concept -- which played a critical role in initiating modern theoretical physics -- from the days of Egyptian hieroglyphs through to Einstein's work in 1905, and beyond. Beginning with the use of the concept of simultaneity in ancient Egypt and in the Bible, the study discusses its role in Greek and medieval philosophy as well as its significance in Newtonian (...) physics and in the ideas of Leibniz, Kant, and other classical philosophers. The central theme of Jammer's presentation is a critical analysis of the use of this concept by philosophers of science, like Poincaré, and its significant role in inaugurating modern theoretical physics in Einstein's special theory of relativity. Particular attention is paid to the philosophical problem of whether the notion of distant simultaneity presents a factual reality or only a hypothetical convention. The study concludes with an analysis of simultaneity's importance in general relativity and quantum mechanics. (shrink)

In this paper the classical topic of “conventionality” in defining the simultaneity (or synchrony) of distant events is tackled again, and the validity of Reichenbach's view is carefully circumscribed. In particular, the role of “one-way” assumptions in the foundations of special relativity is emphasized. The restriction by the round-trip isotropy condition on the admissible distance functions in inertial frames is studied, and its relevance to several issues (absolute simultaneity, the interpretation of Michelson–Morley type experiments, the self-measured speed (...) of a clock) is shown. Two “clock transport” synchronizations in an inertial frame, using self-measured speed and “proper distance,” are presented in detail, and the agreement of the synchronies so established with standard synchrony is proven to be non- circular. By assuming a reasonable concept of “convention” this result is shown to dissolve several objections by supporters of a strong version of conventionalism. Throughout, a number of common misapprehensions in the literature are pointed out. (shrink)

Alleged cases of simultaneous causation have played a prominent role in the critique of various accounts of explanation/causation and in the formation of alternative accounts. It is argued that none of the stated cases are genuine instances of simultaneous causations, since they all violate the special theory of relativity (STR). The conditions a genuine case would have to meet in light of the restrictions imposed by STR are outlined.

In this paper, I elucidate the main points involved in the question of the non-triviality of the conventionality of simultaneity within the kinematics of special relativity. I argue that there is an important distinction to be made between the inherited component and the sui generis component of the conventionality of simultaneity. The factual core of the kinematics of special relativity is explored, and it is shown that the Round-Trip Clock Retardation effect obtains if, and only if (...) Winnie's Passage Time Principle holds. Some consequences of this fundamental fact are then explored. In particular, Grunbaum's view that the epistemological conventionality of simultaneity is logically prior to the physical inter-frame relativity of simultaneity is found to be based largely on what I call the inherited component of the former. Finally, a question is raised as to the very self-consistency of the claim, made by Ellis and Bowman, that standard signal synchrony and slow-transport synchrony are logically independent. In some concluding remarks, the author's general agreement with Grunbaum's conception of bridled conventionalism is indicated. (shrink)

David Malament's (1977) well-known result, which is often taken to show the uniqueness of the Poincare-Einstein convention for defining simultaneity, involves an unwarranted physical assumption: that any simultaneity relation must remain invariant under temporal reflections. Once that assumption is removed, his other criteria for defining simultaneity are also satisfied by membership in the same backward (forward) null cone of the family of such cones with vertices on an inertial path. What is then unique about the Poincare-Einstein convention (...) is that it is independent of the choice of inertial path in a given inertial frame, confirming a remark in Einstein 1905. Similarly, what is unique about the backward (forward) null cone definition is that it is independent of the state of motion of an observer at a point on the inertial path. (shrink)

In his first paper on the special theory of relativity, Einstein indicated that the question of whether or not two spatially separated events were simultaneous did not necessarily have a definite answer, but instead depended on the adoption of a convention for its resolution. Some later writers have argued that Einstein's choice of a convention is, in fact, the only possible choice within the framework of special relativistic physics, while others have maintained that alternative choices, although perhaps less convenient, (...) are indeed possible. (shrink)

We consider the problem of uniqueness of certain simultaneity structures in flat spacetime. Absolute simultaneity is specifiled to be a non-trivial equivalence relation which is invariant under the automorphism group Aut of spacetime. Aut is taken to be the identity-component of either the inhomogeneous Galilei group or the inhomogeneous Lorentz group. Uniqueness of standard simultaneity in the first, and absence of any absolute simultaneity in the second case are demonstrated and related to certain group theoretic properties. (...) Relative simultaneity with respect to an additional structure X on spacetime is specified to be a non-trivial equivalence relation which is invariant under the subgroup in Aut that stabilises X. Uniqueness of standard Einstein simultaneity is proven in the Lorentzian case when X is an inertial frame. We end by discussing the relation to previous work of others. (shrink)

Free will is difficult to classify with respect to determinism or indeterminism, and its phenomenology in consciousness often shows both aspects. Initially, it is felt as unlimited and indeterminate will power, with the potentiality of multiple choices. Thereafter, reductive deliberation is led by determinism to the final decision, which realises only one of the potential choices. The reductive deliberation phase tries to find out the best alternative and simultaneously satisfying vague motivations, contextual conditions and personal preferences. The essential sense of (...) free will is the introduction of personal preferences, which allows a higher diversity of reactions to vague motivations. With an oversimplified model of determinism as a chain of events, incompatibilists define “free” as “undetermined” so that determinism becomes incompatible with any free choice between alternatives. In consciousness, free will requires a more complex model of network determinism as well as the consideration of unconsciousness as a causal factor. When “free” defined as “undetermined” is applied to the context of consciousness, it should be reinterpreted as “unconscious of being determined” or not aware of underlying determinism. Lacking information on determinism generates a feeling of “free” in consciousness and, therefore, gives the impression of indeterminism. Lacking information may be induced by an uncertain future without determined events—an unconscious past with biological reactions suddenly emerging from the unconsciousness or an unknown present unable to distinguish determinism of complex events. Therefore, at the level of human consciousness, the experience of free will is associated with apparent indeterminism although it is based on unconscious determinism. The concepts of compatibilism and incompatibilism are only two different aspects of the same phenomenon and correspond to consciousness and unconsciousness. Nevertheless, they can be considered together with a free will concept based on relativity depending on two different reference frames—the first person’s experience frame or the Laplace’s demon frame with knowledge on every molecule of the universe. Only relativity of the free will concept avoids the contradiction between “free” and “unfree” for the same phenomenon and could be a compromise for considering compatibilism and incompatibilism equally. (shrink)

In 1977, David Malament proved the valuable technical result that the simultaneity relation of standard synchrony $\epsilon=\frac{1}{2}$ with respect to an inertial observer O is uniquely definable in terms of the relation κ of causal connectibility. And he claimed that this definability undermines my own version of the conventionality of metrical simultaneity within an inertial frame.But Malament’s proof depends on the imposition of several supposedly “innocuous” constraints on any candidate for the simultaneity relation relative to O. Relying (...) on Allen I. Janis’s 1983 challenge to one of these constraints, I argue that Malament’s technical result did not undermine my philosophical construal of the ontological status of relative metrical simultaneity. Furthermore, I show that (a) Michael Friedman’s peremptorily substantivalist critique of my conception, which Malament endorses, is ill-founded, and (b) if Malament had succeeded in discrediting my own conventionalist version of metrical simultaneity, he would likewise have invalidated Einstein’s pioneering version of it. (shrink)

The General Theory of Relativity (GR) and the Dynamic Universe (DU) are evaluated in how they explain frequencies of atomic clocks. DU and GR predict the frequencies with equal accuracy, but their explanations, the postulates they apply in the explanations and the word-views that come along with them are entirely different. The central argument is that if unified and under- standable physics is appreciated, then DU deserves to be taken as a viable alternative to GR. In GR different frequencies (...) of identical atomic clocks are explained by letting rates of the flow of time in their frames of reference vary as functions of the clocks’ states of motion and gravitation. The GR- based world-view is nonunderstandable because GR violates absolute simultaneity, and disunified because quantum mechanics is built on different postulates than GR. In DU different frequencies of identical atomic clocks are explained by letting their frequencies vary as functions of their states of motion and gravitation. As DU commits to absolute simultaneity and as the postulates of DU suffice as the ontological ground of quantum mechanics at least partially, DU provides an under- standable and unified scientific world-view. -/- Résumé: La théorie de la relativité générale (RG) et de l’univers dynamique (UD) sont évalués sur la fac ̧on dont ils expliquent les fréquences des horloges atomiques. La RG et l’UD prédisent les fréquences avec une précision égale, mais leurs explications, les postulats qu’ils appliquent aux explications et les visions du monde qui les accompagnent sont entie`rement différents. L’argument central est que si l’on reconnaˆıt la physique unifiée et compréhensible, alors l’UD mérite d’ être considéré comme une alternative viable à la RG. En RG, différentes fréquences d’horloges atomiques identiques sont expliquées en faisant varier les vitesses de l’écoulement du temps dans leurs cadres de référence en fonction des états de mouvement et de la gravitation des horloges. La vue du monde basée sur la RG est incompréhensible parce que la RG viole la simultanéité absolue, et est désunifiée parce que la mécanique quantique est construite sur des postulats différents de ceux de la RG. Dans l’UD, différentes fréquences d’horloges atomiques identiques sont expliquées en laissant leurs fréquences varier en fonction de leurs états de mouvement et de gravitation. Comme l’UD s’engage à la simultanéité absolue et que les postulats de l’UD suffisent, au moins en partie, comme fondements ontologiques de la mécanique quantique, l’UD fournit une vision du monde scientifique compréhensible et unifiée. (shrink)

In 1905 Albert Einstein, in a paper entitled “On the Electrodynamics of Moving Bodies”, as a solution to the disagreement between classical mechanics and the results of the Michelson's experiment, who showed the invariance of the speed of light in vacuum measured in different inertial reference systems, developed the theory of special relativity. In this essay Einstein expounded a theory that, instead of introducing a privileged system, required the revision of the concepts of space and time of classical physics. (...) Combining the principle of Galilean relativity, according to which the laws of physics are invariant in all inertial reference systems, with the physics of electromagnetism, according to which the speed of light in a vacuum is constant, Einstein concluded that time is no more than a relative measure, namely that whenever we have to do with speed equal to or close to that of light, time is no longer a variable absolute and independent of the reference system adopted, but depends on the variable position. This is what Einstein shows through the critical examination of the concept of simultaneity. The abandonment of the traditional conception of space and time based on the idea of a spatial continuum flowing through a temporal continuum coherently leads to the assumption of a space-time continuum in which distances and time intervals vary with the changing the reference system, and together vary, of course, all other sizes to those connected. (shrink)

The conventionality of simultaneity at distant points is defended partly by reference to Einstein's 1905 paper founding special relativity. His famous light-signaling definition takes the transit time of light in one direction to be equal to that in the other. Conventionalists such as Reichenbach and Grunbaum argue that he could have made them unequal without denying any physical fact. However, Einstein's more detailed treatment in the 1910 Archives des sciences runs counter to this thesis. There he required that (...) the two signal-paths be physically equivalent and thus that whatever the signals travel through have no perturbing affect on their motions. (shrink)

To date, both sides in the conventionality of simultaneity debate grant that transformations from "standard" to "nonstandard" coordinates are possible without any empirically significant effects. However, it is argued here that the very possibility of defining nonstandard coordinates vanishes if one represents special relativity, not by real four-vectors (as has been the case so far in the debate), but by complex spinors as used in the representation of half-integer spin. Thus, in the topologically simplest representation of the Lorentz (...) group, the transformation over which the debate has been fought does not exist and one of the most basic foundations of the conventionalist thesis is challenged. (shrink)

Kant’s three Analogies of Experience, in his Critique of Pure Reason, represent a highly condensed attempt to establish the metaphysical foundations of Newtonian physics. His strategy is to show that the organization of experience in terms of a world of enduring substances undergoing mutual causal interaction is a necessary condition of the temporal ordering even of one’s own subjective states, and thus of coherent experience itself. In his Third Analogy—an examination of the necessary conditions of judgments of simultaneous existence—he argues (...) that certain conceptual presuppositions consistent with Newtonian physics are necessary to time-awareness. His argument, however, appears to be undermined by conventionalism in natural science generally, and by the conventionality of simultaneity in particular. In this paper I discuss Kant’s claims in light of contemporary relativity theory. I suggest that, while his project is obsolete in major respects, there may still be useful insights into time-awareness to be drawn from his work. (shrink)

Ellis and Bowman's account of nonstandard signal synchronizations is examined as a prolegomenon to this paper. Attention is called to some consequences of an important ambiguity in their account of the transitivity of nonstandard synchrony. Then an analysis is given of the principle of relativity to assess E & B's claim that this principle either restricts nonstandard signal synchronisms or rules them out altogether. It is argued that the latitude for choices of nonstandard synchronisms is not circumscribed by the (...) factual content of the principle of relativity; instead, the exclusion of such synchronisms by this principle depends on a tacit appeal to the particular conventions implicit in certain formulations of the principle. Hence E & B's claim is rejected as an argument against the factual tenability of nonstandard synchronisms. (shrink)

This book addresses the issue of natural simultaneity of relatives, discussed by Aristotle in Categories 7, 7b15-8a12. Natural simultaneity is a form of symmetrical ontological dependence that holds between items that are not causally linked. In this section of the Categories, Aristotle introduces this topic in his analysis of relatives and maintains that, although relatives seem to be for the most part simultaneous by nature, there seem to be some exceptions. He mentions two pairs of relatives as exceptions, (...) namely the pairs knowledge/knowable and perception/perceptible, and argues at length for the priority of the second relative over the first one in each case. Through a close reading of this text, the author analyses Aristotle's arguments for the thesis of the exceptional character of these pairs and shows that all of them are unsuccessful in supporting the thesis. In order to draw this conclusion, the author highlights and carefully considers the properties that Aristotle is committed to attributing to relatives, taking into account the metaphysical framework of the Categories as well as their specificities within the set of non-substantial categories. Then, he shows that Aristotle's mature views on relatives in the Metaphysics can be construed as committing him to the rejection of such a thesis. Although the issue of natural simultaneity is just one of several that Aristotle considers in his discussion of relatives throughout Categories 7, it is a particularly relevant issue, since it involves a number of puzzles whose analysis allows for a better understanding of the very notion of relativity in Aristotle. This is the first book to explore this issue from the perspective of illuminating the Aristotelian views on relatives. Aristotle on Natural Simultaneity of Relatives in the Categories will appeal to scholars and graduate students working on Aristotle, ancient philosophy in general, and metaphysics. (shrink)

By deriving the Lorentz transformation from the absolute speed of light, Einstein demonstrated the relativistic variability of space and time, enabling him to explain length contraction and time dilation without recourse to a "luminiferous ether" or preferred frame of reference. He also showed that clocks synchronized at a distance via light signals are not synchronized in a frame of reference differing from that of the clocks. However, by mislabeling the relativity of synchrony the "relativity of simultaneity," Einstein (...) implied that this effect concerns an actual difference in times from one frame to another rather than merely a failure of clock synchronization across frames. As a theory of length contraction and time dilation on the basis of relative motion in the context of the absolute speed of light, special relativity is the definitive interpretation of the Lorentz transformation and the correct explanation of relativistic phenomena. The relativity of simultaneity, as I demonstrate, plays no role in this explanation but instead provides apparent justification for a view of time in which the present moment is frame-dependent. In contrast to its legitimate application, special relativity fails as a theory of time on the basis of the relativity of simultaneity. (shrink)

The paper deals with the changes in the sense of synchronicity and simultaneity connected with the transformations in the structure of society. It examines and criticizes the modern concept of absolute chronology, understood as an objective temporal reference common to all observers. This notion is compared with the relative and flexible (but neither objective nor generalizable) forms of synchronization of different societies. The paper discusses finally the hypothesis that contemporary society is realizing a more complex and recursive form of (...) temporality, that questions the modern ideal of synchronicity. This temporality is connected with recent developments in telematics. (shrink)

The A-theory of time has intuitive and metaphysical appeal, but suffers from tension, if not inconsistency, with the special and general theories of relativity (STR and GTR). The A-theory requires a notion of global simultaneity invariant under the symmetries of the world's laws, those ostensible transformations of the state of the world that in fact leave the world as it was before. Relativistic physics, if read in a realistic sense, denies that there exists any notion of global (...) class='Hi'>simultaneity that is invariant under the symmetries of the world's laws. If physics is at least a decent guide to metaphysics--as sympathies for scientific realism would suggest--then relativistic physics supports the B-theory. If there were a physically natural way to modify the symmetries of the physical laws so as to remove those that are repugnant to the A-theory, while retaining empirical adequacy, then such an altered physics might be attractive to the A-theorist and would weaken the support given by relativity to the B-theory. I exhibit a way to do so here, displaying a Lagrangian density explicitly containing distant simultaneity, yet implying Einstein's field equations. The modification involves a change in the nature of the lapse function and makes use of the Dirac-Bergmann formalism of constrained dynamics, which recently has been discussed much by John Earman. Here this formalism is adapted slightly to permit both local and global generalized coordinates. A classification of senses in which time might be absolute or not is made along the way. Some suggestions for extending the work by finding a first principles motivation are made. An appendix outlines an argument why many local presents are insufficient and a global present is attractive, while two more appendices review the Dirac-Bergmann apparatus for GTR and then apply it to the theory at hand. (shrink)

I challenge the assumption in the debate on the conventionality of simultaneity that a simultaneity relation of special relativity should be defined relative to a single inertial observer, not relative to multiple inertial observers as such. I construct an example of a simultaneity relation relative to two inertial observers, and demonstrate that it is explicitly definable in terms of the causal connectibility relation and the world lines of the two observers. I argue that, consequently, thesimultaneity relation (...) of special relativity is not uniquely definable from the causal connectibility relation. (shrink)

What is simultaneous with an event is what can interact with it; events have duration; therefore, any given event has distant events simultaneous with it, even according to Special Relativity. Consequently, the extension of our pre-relativistic judgments of distant simultaneity are largely preserved.

Nearly all accounts of the genesis of special relativity unhesitatingly assume that the theory was worked out in a roughly five week period following the discovery of the relativity of simultaneity. Not only is there no direct evidence for this common presupposition, there are numerous considerations which militate against it. The evidence suggests it is far more reasonable that Einstein was already in possession of the Lorentz and field transformations, that he had applied these to the dynamics (...) of the electron, and that portions of the 1905 paper had actually been drafted well before the epistemological analysis of time. (shrink)

The Einstein-Podolsky-Rosen argument for the incompleteness of quantum mechanics involves two assumptions: one about locality and the other about when it is legitimate to infer the existence of an element-of-reality. Using one simple thought experiment, we argue that quantum predictions and the relativity of simultaneity require that both these assumptions fail, whether or not quantum mechanics is complete.

Einstein, Relativity and Absolute Simultaneity is an anthology of original essays by an international team of leading philosophers and physicists who have come together to reassess the contemporary paradigm of the relativistic concept of time. A great deal has changed since 1905 when Einstein proposed his Special Theory of Relativity, and this book offers a fresh reassessment of Special Relativity’s relativistic concept of time in terms of epistemology, metaphysics, and physics.

The subject of this study is the special theory of relativity (SRT) by A. Einstein, the debate about which has been going on for more than a hundred years. The aim of the study is to evaluate SRT from the side of whether everything that is discussed in this theory and thus in the new, relativistic physics is possible in nature itself. At the same time, the author pays special attention to three issues: the principle of relativity, the (...) necessary condition for the objectivity of the content of scientific theories and the Einstein style of scientific thinking, which predetermined the ideological component of SRT and all relativistic physics. But such issues as relativistic reductions of lengths and durations, the relativity of simultaneity and a single space-time do not remain without attention. The study revealed the fallacy of a long-standing and widespread opinion about the relativity of properties. The necessary condition for the objectivity of scientific theories is revealed. The natural form of expression of quantities is revealed and the non-relative nature of all natural quantities is shown. The hidden form of relativity inherent in the SRT postulate about the constancy of the speed of light in all inertial reference frames and extended in SRT to the magnitude of all lengths and durations considered in it is revealed. It is shown that such relativity is based on the dependence of the quantities on the choice of their reflection systems. It is shown that such dependence is impossible in nature itself. It is concluded that the SRT is erroneous. At the same time, the factors that served as favorable ground for the emergence and spread of this erroneous theory are listed. (shrink)

My aim in this note is to disambiguate various senses of ‘conventional’ that in the philosophy of physics have been frequently conflated. As a case study, I will refer to the well-known issue of the conventionality of simultaneity in the special theory of relativity, since it is particularly in this context that the above mentioned confusion is present.

The main purpose of this paper is to demonstrate that the analysis of the kinematical effects of special relativity holds the key to answering the question of the dimensionality of the world. It is shown that these effects and the experiments which confirmed them would be impossible if the world were three-dimensional. Section 2 shows that relativity of simultaneity, conventionality of simultaneity, and the existence of accelerated observers in special relativity would be impossible if the (...) world were three-dimensional. Section 3 deals with the dimensionality of physical objects and demonstrates that the relativistic length contraction and the twin paradox would be impossible if the physical bodies involved in these relativistic effects were three-dimensional objects. (shrink)

Max Jammer’s recent book, Concepts of Simultaneity: From Antiquity to Einstein and Beyond, traces the history of our ideas on simultaneity as they evolved alongside sweeping changes in our understanding of physics. One of the interesting lessons of the book is that, even as our physical theories have become increasingly successful, the question of the proper understanding or interpretation of those theories remains extremely puzzling. The central issue is this: Is the simultaneity of events a real feature (...) of the world? Or does it depend on the particular choice of reference frame, with any such frame as good as any other? In ancient times, Jammer suggests, most people took the notion of simultaneity for granted: Two events were simultaneous if they happened at the same time. Simultaneity was considered an objective feature of the world. This simple idea appeared con rmed by classical Newtonian mechanics. In Newtonian physics different inertial reference frames (ones that move at a constant velocity relative to one another) are equally good (the laws of motion hold in all of them), even though some attributes of an object, say velocity or momentum, differ from one reference frame to another. However, some features, such as simultaneity, hold in all allowable reference frames and are thus frame independent and in some sense more objective. But what if two events whose simultaneity is in question took place far from each other? How would you know whether they were simultaneous? One solution (available for the last few centuries anyway) is for the observers of each event to look at their (previously synchronized) clocks. The question then becomes, How can clocks that are distant from one.. (shrink)

An often repeated account of the genesis of special relativity tells us that relativity theory was to a considerable extent the fruit of an operationalist philosophy of science. Indeed, Einstein’s 1905 paper stresses the importance of rods and clocks for giving concrete physical content to spatial and temporal notions. I argue, however, that it would be a mistake to read too much into this. Einstein’s operationalist remarks should be seen as serving rhetoric purposes rather than as attempts to (...) promulgate a particular philosophical position --- in fact, Einstein never came close to operationalism in any of his philosophical writings. By focussing on what could actually be measured with rods and clocks Einstein shed doubt on the empirical status of a number of pre-relativistic concepts, with the intention to persuade his readers that the applicability of these concepts was not obvious. This rhetoric manoeuvre has not always been rightly appreciated in the philosophy of physics. Thus, the influence of operationalist misinterpretations, according to which associated operations strictly define what a concept means, can still be felt in present-day discussions about the conventionality of simultaneity. The standard story continues by pointing out that Minkowski in 1908 supplanted Einstein’s approach with a realist spacetime account that has no room for a foundational role of rods and clocks: relativity theory became a description of a four-dimensional ‘absolute world’. As it turns out, however, it is not at all clear that Minkowski was proposing a substantivalist position with respect to spacetime. On the contrary, it seems that from a philosophical point of view Minkowski’s general position was not very unlike the one in the back of Einstein’s mind. However, in Minkowski’s formulation of special relativity it becomes more explicit that the content of spatiotemporal concepts relates to considerations about the form of physical laws. If accepted, this position has important consequences for the discussion about the conventionality of simultaneity. (shrink)

Roy Wood Sellars (1880–1973) is often reduced to his role as father of Wilfrid Sellars. This is unfair because during the 1920s, ‘30s, and ‘40s, Roy Wood was one of the leading figures of the then prevailing American realist movement. In the present paper, I will focus on one particular facet of R. W. Sellars’ philosophical approach: his continual examination of Albert Einstein’s special theory of relativity. I shall primarily reconstruct his discussion of Einstein’s theory, as it can be (...) found in his seminal The Philosophy of Physical Realism (1932). In contrast to authors such as Bertrand Russell or Émile Meyerson, Sellars refused to interpret special relativity in a realist vein. In his view, it should be seen as an “ars mensurandi” and thus being interpreted purely operationally. As with Einstein himself, the concept of simultaneity was his paradigm case in point. However, Sellars opined that besides the physical (mensurational) concepts of time and simultaneity there also exists an ontological understanding of these notions. “Real” time and “absolute” simultaneity are, according to Sellars, the indispensable non-relativistic counterparts to Einstein’s respective relativistic conceptions. They are to be interpreted realistically since they prove, Sellars maintains, to be explanatory regarding events in Einstein-Minkowski’s world. In the course of the paper, I shall compare this view with the one defended by Henri Bergson. Furthermore, Sellars’ later approach from the 1940s and ‘50s will be briefly considered and critically discussed by confronting it with more recent attempts at ontologically ‘grounding’ special relativistic kinematics. (shrink)

The picture which one naturally presents of the situation is that which would arise before an observer placed outside the earth, who could watch the light wave starting from the central mirror and pursuing the distant mirror, catching up with it at some distance beyond the point at which it was when the light wave started. In this case the observer is able to locate the points at which the parts of the apparatus were at different moments and to measure (...) the distances between. We could simulate this situation on the earth by assuming an enclosed square car, from some point in which two balls were shot out in directions at right angles to each other to the walls of the car, bounding back to the point at which they started. We will assume that the balls move with uniform velocity going and coming, and we will assume that the car is moving. An observer outside the car who marked the point on the rail directly over the starting point and the points reached by the balls when they struck the sides of the car, and then measured the distances which the balls travelled, would find that the ball which travelled with the car covered a greater distance than that traversed by the ball which went at right angles to the direction of the train, and yet the balls would return to the starting point at the same moment, provided they travelled over both their paths at the same velocity during their entire trajects, i.e., the same velocity measured within the car. The observer would be at no difficulty to explain this, for he would see that the velocity in the direction of its motion of the car had to be added to that of balls within the car. That is not the case of the light wave. The velocity of a moving shining body is not added to that of the light wave. The wave motion being set up in ether travels with its own uniform velocity of approximately 300,000 kilometers a second. The light waves then, from the standpoint of the observer outside the earth, traverse through the stagnant ether different distances at a uniform velocity and yet the ether waves exhibit on their return none of the evidence which they should exhibit in the interferometer. (shrink)

Modern readers turning to Einstein’s famous 1905 paper on special relativity may not find what they expect. Its title, “On the electrodynamics of moving bodies,” gives no inkling that it will develop an account of space and time that will topple Newton’s system. Even its first paragraph just calls to mind an elementary experimental result due to Faraday concerning the interaction of a magnet and conductor. Only then does Einstein get down to the business of space and time and (...) lay out a new theory in which rapidly moving rods shrink and clocks slow and the speed of light becomes an impassable barrier. This special theory of relativity has a central place in modern physics. As the first of the modern theories, it provides the foundation for particle physics and for Einstein’s general theory of relativity; and it is the last point of agreement between them. It has also received considerable attention outside physics. It is the first port of call for philosophers and other thinkers, seeking to understand what Einstein did and why it changed everything. It is often also their last port. The theory is arresting enough to demand serious reflection and, unlike quantum theory and general relativity, its essential content can be grasped fully by someone merely with a command of simple algebra. It contains Einstein’s analysis of simultaneity, probably the most celebrated conceptual analysis of the century. (shrink)

In this paper a method is proposed for empirically determining simultaneity at a distance within the special theory of relativity. It is argued that this method is independent of Einstein's signalling method and provides a basis for denying the conventionality of distant simultaneity.

It continues to be alleged that superluminal in uences of any sort would be inconsistent with special relativity for the following three reasons: they would imply the existence of a ‘distinguished’ frame; they would allow the detection of absolute motion; and they would violate the relativity of simultaneity. This paper shows that the first two objections rest upon very elementary misunderstandings of Minkowski geometry and on lingering Newtonian intuitions about instantaneity. The third objection has a basis, but (...) rather than invalidating the notion of faster-than-light influences it points the way to more general conceptions of simultaneity that could allow for quantum nonlocality in a natural way. (shrink)

It has been argued that the standard formulation of the Special Theory of Relativity is not only incompatible with presentism, but also strongly indicates the truth of eternalism. We should, however, distinguish two claims concerning the ontological implications of STR: STR is inconsistent with every ontology which requires an absolute relation of simultaneity; and STR implies that eternalism is the only possible ontology of time. There have been a wide range of responses designed to reject these claims, both (...) jointly and independently. For example, one way of rejecting claim is by rejecting claim : thus, one would argue that STR can be revised or interpreted in such a way that it allows an absolute relation of simultaneity. Another way of rejecting claim is by questioning the equivalency of the relation ‘being real as of’. The main purpose of this paper is to raise a new line of objection against concluding eternalism from the relativity of simultaneity. I argue that there is a way to deny claim without denying claim and also without denying the equivalency of relation R. The argument which I present rests on a metaphysical assumption concerning the relation of simultaneity : the assumption that the SIM holds basically between space–time points as opposed to holding basically between events. (shrink)

Eternalism is the view that the past, the present and the future exist simpliciter. A typical argument in favor of this view leans on the relativity of simultaneity. The ‘equally real with’ relation is assumed to be transitive between spacelike separated events connected by hyperplanes of simultaneity. This reasoning is in tension with the conventionality of simultaneity. Conventionality indicates that, even within a specific frame, simultaneity is based on the choice of the synchronization parameter. Hence (...) the argument for eternalism is compromised. This paper lays out alternative eternalist strategies which do not hinge on hyperplanes. While we lack a rigorous proof for eternalism, there are still cogent reasons to prefer eternalism over presentism. (shrink)

Two problems in the paper by EGR are considered. One is the lack of any direct confirmatory evidence for the elegant rational reconstruction. The second is a significant gap in the historical account, just at the critical point in Einstein's discovery process -- namely, the reanalysis of simultaneity. In addition, the EGR account appears in danger of being overly focused on the electrodynamical aspect of special relativity to the exclusion of optical null experiments, and in particular to the (...) exclusion of the role of the 1887 Michelson-Morely interferometer experiment. The author disagrees with Miller on the Kantian aspects of Poincare, and on the role of Anschauungen, preferring to sketch instead a more important role for a Mach-like analysis of fundamental scientific concepts. It is argued that Miller has misconstrued the difference between an axiomatic theory and a "theory of principle" in Einstein's approach. Finally, some suggestions are made as to how the gap in our analysis of Einstein's revolution in simultaneity might be reexamined. (shrink)