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)

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)

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.

Special relativity has been understood by many as vindicating a tenseless conception of time, denying the existence of tensed facts and a fortiori objective temporal passage. The reason for this is straightforward: both passage and the obtaining of tensed facts require a universal knife-edge present moment—yet this structure is not easily reconcilable with the relativity of simultaneity. The above being said, the prospects for tense and passage are sometimes claimed to be improved on moving to cosmological solutions of general relativity. (...) In this paper, we evaluate in detail these arguments, finding that there remain several open questions to be addressed if the introduction of tensed facts into the relativistic context is to be compelling. Moreover, we argue that, even setting aside these issues, objective tense stands and falls in relativity for exactly the same reasons that it does in classical philosophical discussions on the matter. (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)

The special theory of relativity holds significant interest for scientific perspectivists. In this paper, I distinguish between two related meanings of “perspectival,” and argue that reference frames are perspectives, provided that perspectival means “being conditional” rather than “being partial.” Frame-dependent properties such as length, time duration, and simultaneity, are not partially measured in a reference frame, but their measurements are conditional on the choice of frame. I also discuss whether the constancy of the speed of light depends on perspectival factors (...) such as the idealized definition of the speed of light in a perfect vacuum and the Einstein synchronization convention. Furthermore, I argue for the view that the constancy of its speed is a robust property of light according to the conditions of currently acceptable experimental setups pertaining to special relativity, and conclude that this view supports perspectivism. (shrink)

The conventionalistic aspects of physical world perception are reviewed with an emphasis on the constancy of the speed of light in relativity theory and the irreversibility of measurements in quantum mechanics. An appendix contains a complete proof of Alexandrov's theorem using mainly methods of affine geometry.

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)

Philosophy Compass, Volume 17, Issue 4, April 2022.

Taking the formal analogies between black holes and classical thermodynamics seriously seems to first require that classical thermodynamics applies in relativistic regimes. Yet, by scrutinizing how classical temperature is extended into special relativity, I argue that the concept falls apart. I examine four consilient procedures for establishing the classical temperature: the Carnot process, the thermometer, kinetic theory, and black-body radiation. I argue that their relativistic counterparts demonstrate no such consilience in defining the relativistic temperature. As such, classical temperature doesn’t appear (...) to survive a relativistic extension. I suggest two interpretations for this situation: eliminativism akin to simultaneity, or pluralism akin to rotation. (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)

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)

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)

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)

One of the most intuitive views about the metaphysics of laws of nature is Tim Maudlin's idea of a Fundamental Law of Temporal Evolution. So-called FLOTEs are primitive elements of the universe that produce later states from earlier states. While FLOTEs are at home in traditional Newtonian and non-relativistic quantum mechanical theories (not to mention our pre-theoretic conception of the world), I consider here whether they can be made to work with relativity. In particular, shifting to relativistic spacetimes poses two (...) threats to FLOTEs. First, the lack of a privileged spacelike hypersurface in relativistic spacetime makes it unclear how to understand what produces what. A survey of several conceptions of the nomic production relation compatible with relativity reveals all of them to be lacking. Second, relativity motivates a four-dimensional block universe conception of time, according to which all events that will ever occur already exist. On such a view, it's unclear what work there is to be done by FLOTEs. I consider how a proponent of FLOTEs might respond, but conclude that these combined threats seriously undermine the prospects of a productive conception of laws. In short, if spacetime is relativistic, laws are not productive. (shrink)

Historically models of eternity have been grounded in divine attributes rather than the intrinsic structure of space-time. I examine the topology of Minkowski spacetime in comparison to the Euclidean space of Newtonian Mechanics, before highlighting five common approaches to eternity. Both atemporal and temporal models of eternity are examined to establish what they tell us about the nature of eternity outside the divine attributes, before being evaluated for their coherence with the Special Theory of Relativity. I argue that the most (...) coherent models of eternity in light of the Special Theory of Relativity are those that appeal to metaphysical rather than physical time as it remains unaffected by the conventionality and relativity of simultaneity. I conclude that the special Theory of Relativity has a valid role to play in establishing the coherence of eternity. However, due to the discontinuity of concepts of time between the Special Theory of Relativity, the General theory of Relativity and Quantum Mechanics, it cannot single-handedly be used to establish which models of eternity cohere with scientific models of time, but must be use alongside the General theory of Relativity and Quantum Mechanics. (shrink)

This dissertation is about human knowledge of reality. In particular, it argues that scientific knowledge is bounded by historically available instruments and theories; nevertheless, the use of several independent instruments and theories can provide access to the persistent potentialities of reality. The replicability of scientific observations and experiments allows us to obtain explorable evidence of robust entities and properties. The dissertation includes seven chapters. It also studies three cases – namely, Higgs bosons and hypothetical Ϝ-particles (section 2.4), the Ptolemaic and (...) Kepler model of the planets (section 6.7), and the special theory of relativity (chapter 7). -/- Chapter 1 is the introduction of the dissertation. Chapter 2 clarifies the notion of the real on the basis of two concepts: persistence and resistance. These concepts enable me to explain my ontological belief in the real potentialities of human-independent things and the implications of this view for the perceptual and epistemological levels of discussion. On the basis of the concept of “overlapping perspectives”, chapter 3 argues that entity realism and perspectivism are complementary. That is, an entity that manifests itself through several experimental/observational methods is something real, but our knowledge of its nature is perspectival. Critically studying the recent views of entity realism, chapter 4 extends the discussion of entity realism and provides a criterion for the reality of property tokens. Chapter 5, in contrast, develops the perspectival aspects of my view on the basis of the phenomenological-hermeneutical approaches to the philosophy of science. This chapter also elaborates my view of empirical evidence, as briefly expressed in sections 2.5 and 4.5. Chapter 6 concerns diachronic theoretical perspectives. It first explains my view of progress, according to which current perspectives are broader than past ones. Second, it argues that the successful explanations and predictions of abandoned theories can be accounted for from our currently acceptable perspectives. The case study of Ptolemaic astronomy supports the argument of this chapter. Chapter 7 serves as the conclusion of the dissertation by applying the central themes of the previous chapters to the case study of special relativity theory. I interpret frame-dependent properties, such as length and time duration, and the constancy of the speed of light according to realist perspectivism. (shrink)

Unatoč naslovu koji pokriva iznimno opširno područje, članak se usredotočuje na blisko pitanje da li Specijalna teorija relativnosti nužno zagovara ukidanje ontološke razlike između prošlih i budućih događaja, između prošlosti i budućnosti općenito. Izraženo žargonom koji uvodi Stein: jesmo li u okviru STR prinuđeni birati isključivo između ‘solipsizma’ i ‘determinizma’? Posebice će biti riječi o ulozi koju konvencionalnost istovremenosti u STR ima u pokušaju odgovora na ovo pitanje. Standardni argumenti pozivaju se na relativnost istovremenosti, tvrdnju da STR negira postojanje univerzalne (...) ‘sadašnjosti’ koja razgraničava ‘prošlost’ i ‘budućnost’, kako bi pokazali da nema ontološke razlike između prošlosti i budućnosti, da su obje jednako određene/zbiljne . Pritom se prešutno prelazi preko činjenice da je za uspostavu ontoloških tvrdnji vezanih uz relativnost istovremenosti potrebno prvo riješiti pitanje konvencionalnosti istovremenosti u okviru STR. U članku će se nastojati pokazati da promatranjem pitanja konvencionalnosti istovremenosti iz perspektive ‘čisto filozofskog’ Dummettovog određenja razlike između prošlosti i budućnosti možemo u okviru STR pokušati razviti shvaćanje razlikovanja prošlosti i budućnosti mimo stroge ontološke dihotomije ‘solipsizam’/‘determinizam’, ukoliko kriterij koji postavlja STR shvatimo kao epistemički, a ne kao ontološki.Despite a broad-range title the paper settles for the related issue of whether the Special Theory of Relativity necessarily advocates the demise of an ontological difference between past and future events, between past and future in general. In the jargon of H. Stein: are we forced, within the framework of the STR, to choose only between ‘solipsism’ and ‘determinism’ exclusively? A special emphasis is placed on the role that the conventionality of simultaneity plays in the STR with regards to this question. The standard arguments rely on the relativity of simultaneity, the claim that the STR negates the existence of a universal ‘present’ that divides the ‘past’ and the ‘future’, so as to conclude that there is no ontological difference between past and future events, that both are equally determined/real . This often neglects the fact that to establish the ontological claims related to relativity of simultaneity, one must first resolve the issues of conventionality of simultaneity within the STR. The paper will aim to show that by addressing the issue of conventionality from Dummett’s ‘purely philosophical’ determination of the difference between the past and the future, we develop an understanding of the said difference, within the framework of the STR, beyond the strict ontological dichotomy of ‘solipsism/determinism’, given that the criterion that is provided by the STR is understood as epistemic and not ontological. (shrink)

This is a copy of my DPhil thesis, the abstract for which is as follows: The first third of this thesis argues for a B-theoretic conception of time according to which all times exist equally and the present is in no way privileged. I distinguish "ontological" A-theories from "non-ontological" ones, arguing that the latter are experientially unmotivated and barely coherent. With regard to the former, I focus mainly on presentism. After some remarks on how to formulate this (and eternalism) non-trivially, (...) I review the non-relativistic case against presentism. I then consider the impact of Special Relativity on the debate, and attempt to deepen this impact by supplying a modal variation on the standard arguments. The middle third of the thesis investigates persistence, contending that both endurance and perdurance are consonant with the eternalism already endorsed. After introducing these theories of persistence, and discussing in particular how best to formulate an eternalist endurance, I proceed to defend the coherence of this combination. The Problem of Change is addressed here. I then respond in some detail to recent allegations of relativistic threats to endurance. The final third of the thesis questions the validity of the endurantist-perdurantist dispute. I criticize two recently proposed translation schemes that aim to show this dispute to be non-substantive. However, the second scheme suggests a doctrine of "Ontological Equivalence" which I develop and consider. I then address the Rotating Discs Argument, using this to launch a discussion of identity, genidentity, and the relationship between them. (shrink)

I develop Special Relativity with backward-light-cone simultaneity, which I call, for reasons made clear in the paper, ‘Apparent Simultaneity’. In the first section I show some advantages of this approach. I then develop the kinematics in the second section. In the third section I apply the approach to the Twins Paradox: I show how it removes the paradox, and I explain why the paradox was a result of an artificial symmetry introduced to the description of the process by Einstein’s simultaneity (...) definition. In the fourth section I discuss some aspects of dynamics. I conclude, in a fifth section, with a discussion of the nature of light, according to which transmission of light energy is a form of action at a distance. -/- deposited in Pittsburgh PhilSci-Archive, March 2007. (shrink)

In recounting his discovery of special relativity, Einstein recalled a debt to the philosophical writings of Hume and Mach. I review the path Einstein took to special relativity and urge that, at a critical juncture, he was aided decisively not by any specific doctrine of space and time, but by a general account of concepts that Einstein found in Hume and Mach’s writings. That account required that concepts, used to represent the physical, must be properly grounded in experience. In so (...) far as they extended beyond that grounding, they were fictional and to be abjured (Mach) or at best tolerated (Hume). Einstein drew a different moral. These fictional concepts revealed an arbitrariness in our physical theorizing and may still be introduced through freely chosen definitions, as long as these definitions do not commit us to false presumptions. After years of failed efforts to conform electrodynamics to the principle of relativity and with his frustration mounting, Einstein applied this account to the concept of simultaneity. The resulting definition of simultaneity provided the reconceptualization that solved the problem in electrodynamics and led directly to the special theory of relativity. (shrink)

An important epistemological lesson can be learned from the impossibility to determine the one-way velocity of light and the immediate implication that simultaneity is conventional. The vicious circle -- to determine whether two distant events are simultaneous we need to know the one-way velocity of light between them, but to determine the one-way velocity of light we need to know that the two events are simultaneous -- is an indication of the need for a profound change of our view on (...) reality. (shrink)

Hans C. Ohanian 1 claims to “defeat” the conventionalist thesis of clock synchronization using an argument based on dynamics. My aim here is to show that his argument does not succeed.