Simultaneity

This paper proposes an interpretation of time that incorporates both McTaggart's A-series and his B-series, and attempts to cast it in a way that might be usable by physicists. This interpretation allows one to reconcile special relativity with temporal becoming as the latter is understood as 'ontologically private', which is given a mathematical definition. This allows one to define a unit of becoming, as well as the rates of becoming. This paper gives a picture of this interpretation and applies a (...) rough outline of the concepts to several test cases. (shrink)

I accept that McTaggart's A-series and B-series are not inter-reducible and that both are needed for a complete temporal description of a physical system. I consider the Wigner's Friend thought experiment. The A-series are associated with each (quantum) system, and relativity is associated with the B-series. I consider temporal evolution through this 'hybrid' time. We may define the rate of temporal flow as 1 B-series second per A-series second.

More on McTaggart's AB-series in physics, with integrals.

How can McTaggart's A-series notion of time be incorporated into physics while retaining the B-series notion? It may be the A-series 'now' can be construed as ontologically private. How is that modeled? Could a definition of a combined AB-series entropy help with the Past Hypothesis problem? What if the increase in entropy as a system goes from earlier times to later times is canceled by the decrease in entropy as a system goes from future, to present, to past?

The popular metaphysical view that concrete objects are grounded in their ultimate parts is often motivated by appeals to realist interpretations of contemporary physics. This paper argues that an examination of mainstream interpretations of quantum mechanics undercuts such atomist claims. First, mereological atomism is only plausible in conjunction with Bohmian mechanics. Second, on either an endurantist or perdurantist theory of time, atomism exacerbates Bohmianism’s existing tensions with serious Lorentz invariance in a way that undermines the realist appeal of both views. (...) Bohmians should therefore resist atomism, leaving atomists somewhat physically homeless. (shrink)

This paper presents an attempt to define temporal coincidence starting from the first principles. The temporal coincidence defined here differs from Einstein’s simultaneity for it is invariant across inertial frames - not relative. The meaning and significance of temporal coincidence is derived from axioms of existence and it somehow relates to Kant’s notion of simultaneity. Consistentl y applied to the Special Theory of Relativity framework, temporal coincidence does not in any way create mathematical contradictions; however it allows looking at some (...) common relativity claims with a dose of scepticism. Time, as derived from Lorentz transformations, appears to be conventional in order to match the postulate of constancy of the speed of light. The relative simultaneity is only apparent due to that convention. There are insufficient grounds to claim that inertial systems moving relatively to each other have their own different temporal realities. Overall, the innate temporal logic we have is not erroneous and does not need to be replaced contrary to the claims of some relativity educators. (shrink)

This paper presents the proof of the apparent nature of relative simultaneity originally derived from Einstein’s Special Theory of Relativity (STR). The proof does not challenge the validity of the STR but uncovers fundamental and widespread error in understanding of practical implications of Lorentz transformations. It is demonstrated that more than a century long debates generally miss the point. This results in counterintuitive claims of coexisting multiple time realities by mere equivalence of equal clock indications and simultaneity. Such claims have (...) little empirical significance but they are substantial in education and philosophy which has become utterly confused after universal acceptance of the STR and rejections of Henri Bergson’s challenge. There is nothing more to “relative simultaneity” other than the effect of identical clocks being shifted by an offset which depends on synchronisation method. (shrink)

Historians have shown that philosophical discussions about the implications of relativity significantly shaped the development of European philosophy of science in the 1920s. Yet little is known about American debates from this period. This paper maps the first responses to Einstein’s theory in three U.S. philosophy journals and situates these papers within the local intellectual climate. We argue that these discussions (1) stimulated the development of a distinctly American branch of philosophy of science and (2) paved the way for the (...) logical empiricists, who emigrated to the United States in the years before World War II. (shrink)

This paper argues that qualia share their physical correlates' locations. The first premise comes from the theory of relativity: If something shares a time with a physical event in all reference frames, it shares that physical event’s location. The second premise is that qualia share times with their correlates in all reference frames. Having qualia and correlates share locations makes relations between them easier to explain, improving both physicalist and dualist theories.

The concept of inertial frame of reference in classical physics and special theory of relativity is analysed. It has been shown that this fundamental concept of physics is not clear enough. A definition of inertial frame of reference is proposed which expresses its key inherent property. The definition is operational and powerful. Many other properties of inertial frames follow from the definition, or it makes them plausible. In particular, the definition shows why physical laws obey space and time symmetries and (...) the principle of relativity, it resolves the problem of clock synchronization and the role of light in it, as well as the problem of the geometry of inertial frames. (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 aim of this thesis is to defend a presentist metaphysics. I respond to a series of objections against presentism, including some that draw on our best physics. I also explore ways in which presentism might play an active role in interpreting and constraining physical theory, beyond merely being consistent with it. -/- A unifying theme of this thesis is that I advocate for a reduction of presentism to its bare essentials. Within the proposed ontology, reality is three-dimensional. Time only (...) exists in the sense that three-dimensional reality primitively changes. I reject any temporal dimension, extension, or direction. I reject any primitively tensed facts or nonpresent-tensed truths. I also reject any notion of simultaneity, beyond the mere fact that multiple entities exist in the three-dimensional world. I accept and embrace that if ontology is ‘stripped back’ to the present, then other features of metaphysics that depend on ontology should be stripped back too. -/- The world, under this view, is a forgetful one. What we call the ‘past’ has been utterly lost from existence: there are not even any absolute facts or truths about how things once were. All that remain are records, memories, and the like, but there are no objective underlying truths to which those records correspond. This has implications for physics. In a forgetful world particles have positions, but no entire trajectories. The present may be certain and determinate, but the past and future are at best modelled using probabilistic mathematics. -/- I believe that the world is likely to be as I describe. I will not attempt to argue, however, that this view is intuitive. Instead I will argue that it can account for our experiences and observations, including those from physics, in a simple and effective way. Most importantly, I argue that this view succeeds in the face of challenges where other versions of presentism fail. (shrink)

The article summarizes the software tool on astrophysical analysis with multi-wavelength space telescope data. It recaps the evidence analysis conducted on the Kerr-Newman black hole (KNBH). It was written prior to the article Research on the Kerr-Newman Black Hole in M82 Confirms Black Hole and White Hole Juxtapose not soon after the experiment. The conducted analysis suggested Hawking radiation is caused by the movement of ergosurfaces of the BH and serves as the primal evidence for black hole and white hole (...) juxtapose. A later data exploration was conducted with the radiation trails in the multi-wavelength data. The evidences produced corroborates with Yale professor Priyamvada Natarajan's black hole seeds theory. It implies that the electromagnetic dynamic of fusion and fission temperature determines the pressure of surface tension on the macro particles, and the mass density of the BH is determined by the electromagnetic tension between the outer ergosurface and inner ergosurface. The ring singularity of the BH and the Penrose-Hawking singularity of the BH determine the spin and gravitational singularity of the BH. Inside the ergosurfaces, the BH singularities' backward inflow causes the vicinity's rate on feeding the BH. It makes the active galactic nuclei (AGN) a semi-closed system. The density pressure is released on threshold. During the mass exchange observed by energy momentum upon the AGN's open, the macroparticle composition of the BH changes with the galactic event. This causes the expansion rate of the galaxy and contraction rate of the BH. AGN types and their relative motions determine the expansion rate of the cosmic universe in a generalized quantitative thinking. The article concludes that BH spin is caused by the asymmetric motions of AGN in the BH system. A set of the nuclear resonance caused by BH and white hole (WH) oscillation is processed with the same set of data. (shrink)

Privileged-perspective realism (PPR) is a version of metaphysical realism that takes certain irreducibly perspectival facts to be partly constitutive of reality. PPR asserts that there is a single metaphysically privileged standpoint from which these perspectival facts obtain. This chapter discusses several views that fall under the category of privileged-perspective realism. These include presentism, which is PPR about tensed facts, and non-multiverse interpretations of quantum mechanics, which the chapter argues, constitute PPR about world-indexed facts. Using the framework of the bird perspective (...) and the frog perspective, it argues that PPR views methodologically treat the frog perspective as metaphysically primary. This chapter considers case studies of metaphysical interpretations of special relativity and quantum mechanics in order to demonstrate that such motivations for PPR are non-naturalistic. Further, it considers psychological factors that motivate the appeal of PPR views and offers naturalistic explanations of why we should not expect them to produce an adequate metaphysics of science. (shrink)

Eternalism is the view that all times are equally real. The relativity of simultaneity in special relativity backs this up. There is no cosmically extended, self-existing ‘now.’ This leads to a tricky problem. What makes statements about the present true? I shall approach the problem along the lines of perspectival realism and argue that the choice of the perspective does. To corroborate this point, the Lorentz transformations of special relativity are compared to the structurally similar equations of the Doppler effect. (...) The ‘now’ is perspectivally real in the same way as a particular electromagnetic spectrum frequency. I also argue that the ontology of time licensed by perspectival realism is more credible in this context than its current alternative, the fragmentalist interpretation of special relativity. (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.

The theory of space-time developed in Kant’s Critique of Pure Reason and his Metaphysical Foundations of Natural Science is connected to Leonhard Euler’s proof of invariance under Galilean transformations in the “On Motion in General” of the latter’s 1736 Analytical Mechanics. It is argued that Kant, by using the Principle of Relativity that is the output of Euler’s proof as an input to his own proof of the kinematic parallelogram law, makes essential use of absolute simultaneity. This is why, in (...) the Transcendental Aesthetic, he observes that “our theory of time explains as much a priori knowledge as the general theory of motion displays.” In conclusion, it is shown that the same proof-method, under a different definition of simultaneity, leads to the parallelogram law of the “Kinematic Part” of Einstein’s 1905 “On the Electrodynamics of Moving Bodies”. (shrink)

The conventionality of simultaneity thesis as established by Reichenbach and Grünbaum is related to the partial freedom in the definition of simultaneity in an inertial reference frame. An apparently altogether different issue is that of the conventionality of spatial geometry, or more generally the conventionality of chronogeometry when taking also into account the conventionality of the uniformity of time. Here we will consider Einstein’s version of the conventionality of geometry, according to which we might adopt a different spatial geometry and (...) a particular definition of equality of successive time intervals. The choice of a particular chronogeometry would not imply any change in a theory, since its “physical part” can be changed in a way that, regarding experimental results, the theory is the same. Here, we will make the case that the conventionality of simultaneity is closely related to Einstein’s conventionality of chronogeometry, as another conventional element leading to it. (shrink)

The foundation of irreversible, probabilistic time -- the classical time of conscious observation -- is the reversible and deterministic time of the quantum wave function. The tendency in physics is to regard time in the abstract, a mere parameter devoid of inherent direction, implying that a concept of real time begins with irreversibility. In reality time has no need for irreversibility, and every invocation of time implies becoming or flow. Neither symmetry under time reversal, of which Newton was well aware, (...) nor the absence of an absolute parameter, as in relativity, negates temporal passage. Far from encapsulating time, irreversibility is a secondary property dependent on the emergence of distinct moments from the ceaseless presence charted by the wave function. (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 this work we will consider gauge interpretations of the conventionality of simultaneity as developed initially by Anderson and Stedman, and later by Rynasiewicz. We will make a critical reassessment of these interpretations in relation to the “tradition” as developed in particular by Reichenbach, Grünbaum, and Edwards. This paper will address different issues, including: the relation between these two gauge interpretations; what advantages or defects these gauge approaches might have; how “new” Rynasiewicz’s approach in relation to the previous ones is; (...) how much of the gauge interpretation Rynasiewicz actually applies to deal with objections to the conventionality of simultaneity thesis. The conclusion is that the gauge interpretations, in their current formulation, do not provide a better “rationale” of the conventionality of simultaneity thesis that supersedes the “tradition”. (shrink)

Albert Einstein's bold assertion of the form-invariance of the equation of a spherical light wave with respect to inertial frames of reference became, in the space of six years, the preferred foundation of his theory of relativity. Early on, however, Einstein's universal light-sphere invariance was challenged on epistemological grounds by Henri Poincaré, who promoted an alternative demonstration of the foundations of relativity theory based on the notion of a light-ellipsoid. Drawing in part on archival sources, this paper shows how an (...) informal, international group of physicists, mathematicians, and engineers, including Einstein, Paul Langevin, Poincaré, Hermann Minkowski, Ebenezer Cunningham, Harry Bateman, Otto Berg, Max Planck, Max Laue, A. A. Robb, and Ludwig Silberstein, employed figures of light during the formative years of relativity theory in their discovery of the salient features of the relativistic worldview. (shrink)

Albert Einstein’s bold assertion of the form invariance of the equation of a spherical light wave with respect to inertial frames of reference became, in the space of 6 years, the preferred foundation of his theory of relativity. Early on, however, Einstein’s universal light-sphere invariance was challenged on epistemological grounds by Henri Poincaré, who promoted an alternative demonstration of the foundations of relativity theory based on the notion of a light ellipsoid. A third figure of light, Hermann Minkowski’s lightcone also (...) provided a new means of envisioning the foundations of relativity. Drawing in part on archival sources, this paper shows how an informal, international group of physicists, mathematicians, and engineers, including Einstein, Paul Langevin, Poincaré, Hermann Minkowski, Ebenezer Cunningham, Harry Bateman, Otto Berg, Max Planck, Max von Laue, A. A. Robb, and Ludwig Silberstein, employed figures of light during the formative years of relativity theory in their discovery of the salient features of the relativistic worldview. (shrink)

While Einstein considered that sub specie astern the correct philosophical position regarding geometry was that of the conventionality of geometry, he felt that provisionally it was necessary to adopt a non-conventional stance that he called practical geometry. here we will make the case that even when adopting Einstein’s views we must conclude that practical geometry is conventional after all. Einstein missed the fact that the conventionality of simultaneity leads to a conventional element in the chrono-geometry, since it corresponds to the (...) possibility of different space-time metrics. (shrink)

ABSTRACT In Einstein’s physical geometry, the geometry of space and the uniformity of time are taken to be non-conventional. However, due to the stipulation of the isotropy of the one-way speed of light in the synchronization of clocks, as it stands, Einstein’s views do not seem to apply to the whole of the Minkowski space-time. In this work we will see how Einstein’s views can be applied to the Minkowski space-time. In this way, when adopting Einstein’s views, chronogeometry is a (...) physical chronogeometry. (shrink)

It is said what aggregative properties are and also what emergent properties are, and examples are given each of kind of property. It is also explained why, even though all emergent properties are aggregative properties, not all aggregative properties are emergent properties. It is further made clear that, strictly speaking, emergence is a property of one's knowledge of a given kind of aggregate, and not of such aggregates themselves, this being why a property that is emergent at one time will, (...) when additional information becomes available, cease to be emergent. And it is explained why, for this very reason, the right answer to the question 'why does X exist?' is never 'because X is an emergent property.'. (shrink)

It is clearly stated what time-travel would be, were it possible, and it is thereby shown that the very concept of time-travel is incoherent.

Two radically different views about time are possible. According to the first, the universe is three dimensional. It has a past and a future, but that does not mean it is spread out in time as it is spread out in the three dimensions of space. This view requires that there is an unambiguous, absolute, cosmic-wide "now" at each instant. According to the second view about time, the universe is four dimensional. It is spread out in both space and time (...) - in space-time in short. Special and general relativity rule out the first view. There is, according to relativity theory, no such thing as an unambiguous, absolute cosmic-wide "now" at each instant. However, we have every reason to hold that both special and general relativity are false. Not only does the historical record tell us that physics advances from one false theory to another. Furthermore, elsewhere I have shown that we must interpret physics as having established physicalism - in so far as physics can ever establish anything theoretical. Physicalism, here, is to be interpreted as the thesis that the universe is such that some unified "theory of everything" is true. Granted physicalism, it follows immediately that any physical theory that is about a restricted range of phenomena only, cannot be true, whatever its empirical success may be. It follows that both special and general relativity are false. This does not mean of course that the implication of these two theories that there is no unambiguous cosmic-wide "now" at each instant is false. It still may be the case that the first view of time, indicated at the outset, is false. Are there grounds for holding that an unambiguous cosmic-wide "now" does exist, despite special and general relativity, both of which imply that it does not exist? There are such grounds. Elsewhere I have argued that, in order to solve the quantum wave/particle problem and make sense of the quantum domain we need to interpret quantum theory as a fundamentally probabilistic theory, a theory which specifies how quantum entities - electrons, photons, atoms - interact with one another probabilistically. It is conceivable that this is correct, and the ultimate laws of the universe are probabilistic in character. If so, probabilistic transitions could define unambiguous, absolute cosmic-wide "nows" at each instant. It is entirely unsurprising that special and general relativity have nothing to say about the matter. Both theories are pre-quantum mechanical, classical theories, and general relativity in particular is deterministic. The universe may indeed be three dimensional, with a past and a future, but not spread out in four dimensional space-time, despite the fact that relativity theories appear to rule this out. These considerations, finally, have implications for views about the arrow of time and free will. (shrink)

This paper analyzes the ontology and epistemology of time in Lucretius’ De rerum natura. It uses the physiology of perception as well as epistemology to shed new light on the metaphysics. It presents an exegesis-based interpretation of the nature of time and of its perception, both arguing for and refining this interpretation by showing its explanatory power. The paper shows that Lucretius represents the perception of time or sensus temporis as a distinct sensory faculty, reconstructs how it emerges and operates, (...) and relates it to his account of perception more generally. The sense of time in turn is seen to explain aspects of related faculties, including thought and sight, and cases of apparent simultaneity. The paper thus contributes to, among other things, our understanding of the speed of perception and Lucretius’ account of the nature of time itself — arguing that Lucretius represents time as both continuous (not atomic) and real, as well as something perceived. (shrink)

I reconstruct from Rietdijk and Putnam’s well-known papers an argument against the applicability of the concept of becoming in Special Relativity, which I think is unaffected by some of the objections found in the literature. I then consider a line of thought found in the discussion of the possible conventionality of simultaneity in Special Relativity, beginning with Reichenbach, and apply it to the debate over becoming. We see that it immediately renders Rietdijk and Putnam’s argument unsound. I end by comparing (...) my approach to others found in the literature, primarily Stein’s. (shrink)

By eliminating the need for an absolute frame of reference or ether, Einstein resolved the problem of the constancy of light-speed in all inertial frames but created a new problem in our understanding of time. The resolution of this problem requires no experimentation but only a careful analysis of special relativity, in particular the relativity of simultaneity. This concept is insufficiently relativistic insofar as Einstein failed to recognize that any given set of events privileges the frame in which the events (...) occur; relative to those events, only the privileged frame yields the correct measurement. Instead of equally valid frames occupying different times, one frame is correct and all others incorrect within a shared present moment. I conclude that (1) time is a succession of universal moments and (2) in the context of flowing time, time dilation requires absolute simultaneity, whereas relative simultaneity predicts a nonexistent phenomenon here dubbed time regression. (shrink)

We investigate whether standard counterfactual analyses of causation imply that the outcomes of space-like separated measurements on entangled particles are causally related. Although it has sometimes been claimed that standard CACs imply such a causal relation, we argue that a careful examination of David Lewis’s influential counterfactual semantics casts doubt on this. We discuss ways in which Lewis’s semantics and standard CACs might be extended to the case of space-like correlations.

Zur Aufklärung der vielschichtigen Beziehungen zwischen Lebenswelt und Physik diskutiere ich die für die beiden Erfahrungsweisen jeweils typischen Konzeptualisierungen von Zeit. Nach einer Einleitung beginne ich mit der Analyse der subjektiven und objektiven lebensweltlichen Zeitformen. Anschließend erörtere ich im dritten Abschnitt das Verhältnis von lebensweltlichen und physikalischen Elementen der Weltzeit. Vier physikalische Zeitverständnisse stelle ich in ihrer Differenz zur lebensweltlichen Auffassung im vierten Abschnitt dar. Historisch hat sich die generelle Tendenz zur Vergrößerung dieser Differenz fortgesetzt, ohne dass schon Instanzen zur (...) Vermittlung der divergierenden Begriffe entstanden wären. Vor diesem Hintergrund plädiere ich im abschließenden Teil für eine plurale Begrifflichkeit. (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)

Recently-discovered manuscripts throw new light on Poincaré’s discovery of the Lorentz group, and his ether-based interpretation of the Lorentz transformation. At first, Poincaré postulated longitudinal contraction of bodies in motion with respect to the ether, and ignored time deformation. In April, 1909, he acknowledged temporal deformation due to translation, obtaining thereby a theory of relativity more compatible with those of Einstein and Minkowski.

This is a short, nontechnical introduction to features of time in classical and relativistic physics and their representation in the four-dimensional geometry of spacetime. Topics discussed include: the relativity of simultaneity in special and general relativity; the ‘twin paradox’ and differential aging effects in special and general relativity; and time travel in general relativity.

Malament (Noûs 11:293–300, 1977) proved a certain uniqueness theorem about standard synchrony, also known as Poincaré-Einstein simultaneity, which has generated many commentaries over the years, some of them contradictory. We think that the situation called for some clarification. After reviewing and discussing some of the literature involved, we prove two results which, hopefully, will help clarifying this debate by filling the gap between the uniquess of Malament’s theorem, which allows the observer to use very few tools, and the complete arbitrariness (...) of a time coordinate in full-fledged Relativity theory. In the spirit of Malament’s theorem, and in opposition to most of its commentators, we emphasize explicit definability of simultaneity relations, and give only constructive proofs. We also explore what happens when we reduce to “purely local” data with respect to an observer. (shrink)

The paper reviews Balashov’s Asymmetry Thesis concerning co-existing (point-sized) enduring objects, on the one hand, and perduring ones, on the other. In this regard, it becomes crucial to investigate whether, at a given spacetime point p, it is located only the respective temporal part of a perdur- ing whole, or that whole as well. Two alternatives ought to be distinguished and, then, I will argue as follows: If the perduring whole is located where its parts are, the original asymmetry- thesis (...) has to be rejected. If, however, the perduring whole is not located where its parts are, the spatiotemporal locations of the parts can no longer be used to ground the co-existence relation. But, with the modified co-existence relation the asymmetry between perdurantism and endurantism turns out to be even much stronger than it has been assumed. (shrink)

This paper deals with the concept of simultaneity in classical and relativistic physics as construed in terms of group-invariant equivalence relations. A full examination of Newton, Galilei and Poincaré invariant equivalence relations in ℝ4 is presented, which provides alternative proofs, additions and occasionally corrections of results in the literature, including Malament’s theorem and some of its variants. It is argued that the interpretation of simultaneity as an invariant equivalence relation, although interesting for its own sake, does not cut in the (...) debate concerning the conventionality of simultaneity in special relativity. (shrink)

As is well know from Einstein the choice of a criterion for distant simultaneity is equivalent to stipulating one-way speeds for the transit of light. It is shown that any choice of non-standard synchrony is equivalent to a Lorentz local time boost. From this and considerations from the hole argument, it follows that there is a non-trivial sense in which distant simultaneity is conventional, at least to the extent that the “gauge freedom” arising in the hole argument is non-trivial.

Does the status of certain temporal experiences as illusory depend on one’s conception of time? Our concept of time in part determines our concept of what we hold to be real and unreal; what we hold to be real and unreal partially determines what we hold to be illusory; thus, our concept of time in part determines what we hold to be illusory. This paper argues that this dependency of illusions on the concept of time is applicable to illusions of (...) time. Two possible temporal illusions given the evidence are examined, simultaneity and the experience of the past; it is argued that the evidence points at temporal illusions depending on which conception of time is true. (shrink)

The Special Theory of Relativity (STR) holds sway as a theory of time due to its apparently successful predictive structure regarding time-related phenomena such as the increased life spans of mesons or retarded clocks on jets circling the globe, and due to the relativization of simultaneity intrinsic to this theoretical structure. Yet the very structure of the theory demands that such very real physical effects be construed as non-ontological. The scope and depth of this contradiction is explored and, if these (...) time-changes are indeed viewed as ontological effects within STR, an additional problem for the theory is introduced in the context of perception. The origins of this confused situation arise as a result of the fact that STR is an expression of a classical, spatial metaphysic – a framework that equally underpins current discussions of the hard problem. This metaphysic holds an inadequate concept of time and a failure to acknowledge the reality of simultaneous causal flows. These problems are developed against the background of an alternative, namely, the temporal metaphysic of Bergson – a framework that provides a profoundly different base for viewing both relativity and consciousness. (shrink)

According to the conventionalist doctrine of space elaborated by the French philosopher-scientist Henri Poincaré in the 1890s, the geometry of physical space is a matter of definition, not of fact. Poincaré’s Hertz-inspired view of the role of hypothesis in science guided his interpretation of the theory of relativity (1905), which he found to be in violation of the axiom of free mobility of invariable solids. In a quixotic effort to save the Euclidean geometry that relied on this axiom, Poincaré extended (...) the purview of his doctrine of space to cover both space and time. The centerpiece of this new doctrine is what he called the ‘‘principle of physical relativity,’’ which holds the laws of mechanics to be covariant with respect to a certain group of transformations. For Poincaré, the invariance group of classical mechanics defined physical space and time (Galilei spacetime), but he admitted that one could also define physical space and time in virtue of the invariance group of relativistic mechanics (Minkowski spacetime). Either way, physical space and time are the result of a convention. (shrink)

Alternative theories of relativistic rotation considered viable as of 2004 are compared in the light of experiments reported in 2005. En route, the contentious issue of simultaneity choice in rotation is resolved by showing that only one simultaneity choice, the one possessing continuous time, gives rise, via the general relativistic equation of motion, to the correct Newtonian limit Coriolis acceleration. In addition, the widely dispersed argument purporting Lorentz contraction in rotation and the concomitant curved surface of a rotating disk is (...) analyzed and argued to be lacking for more than one reason. It is posited that not by theoretical arguments, but only via experiment can we know whether such effect exists in rotation or not. The Coriolis/simultaneity correlation, and the results of the 2005 experiments, support the Selleri theory as being closest to the truth, though it is incomplete in a more general applicability sense, because it does not provide a global metric. Two alternatives, a modified Klauber approach and a Selleri–Klauber hybrid, are presented which are consistent with recent experiment and have a global metric, thereby making them applicable to rotation problems of all types. (shrink)

David Malament tried to show that the causal theory of time leads to a unique determination of simultaneity relative to an inertial observer, namely standard simultaneity. I show that the causal relation Malament uses in his proofs, causal connectibility, should be replaced by a different causal relation, the one used by Reichenbach in his formulation of the theory. I also explain why Malament's reliance on the assumption that the observer has an eternal inertial history modifies our conception of simultaneity, and (...) I therefore eliminate it. Having made these changes, Malament's uniqueness result no longer follows, although the conventionality of simultaneity is not reinstated. I contrast my approach with previous criticisms of Malament. Introduction Causality and Temporal Order Malament's Argument Causality versus Causal Connectibility Simultaneity and History Conclusion. (shrink)