The Reichenbach-Grunbaum thesis of the conventionality of simultaneity is clarified and defended by developing the consequences of the Special Theory when assumptions are not made concerning the one-way speed of light. It is first shown that the conventionality of simultaneity leads immediately to the conventionality of all relative speeds. From this result, the general-length-contraction and time-dilation relations are then derived. Next, the place of time-dilation and length-contraction effects within the Special Theory is examined in the light of the conventionality thesis. (...) The slow-transport method of synchrony is then examined in the light of these results and is shown not to provide an adequate method of uniquely determining the one-way speed of light. Finally, the general ε -Lorentz transformations for events along the x-axis are derived from three principles: the round-trip light principle, the principle of equal passage times, and the linearity principle. These principles are shown to be independent of one-way velocity assumptions, and thus may form the basis of a Special Theory of Relativity without distant simultaneity assumptions. (shrink)

The Reichenbach-Grunbaum thesis of the conventionality of simultaneity is clarified and defended by developing the consequences of the Special Theory when assumptions are not made concerning the one-way speed of light. It is first shown that the conventionality of simultaneity leads immediately to the conventionality of all relative speeds. From this result, the general-length-contraction and time-dilation relations are then derived. Next, the place of time-dilation and length-contraction effects within the Special Theory is examined in the light of the conventionality thesis. (...) The slow-transport method of synchrony is then examined in the light of these results and is shown not to provide an adequate method of uniquely determining the one-way speed of light. Finally, the general ε -Lorentz transformations for events along the x-axis are derived from three principles: the round-trip light principle, the principle of equal passage times, and the linearity principle. These principles are shown to be independent of one-way velocity assumptions, and thus may form the basis of a Special Theory of Relativity without simultaneity assumptions. (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)

This chapter contains sections titled: Relationism, Substantivalism and Space‐time Conventionalism about Space‐time Black Holes and Singularities Horizons and Uniformity Conclusion.

The axiomatic bases of Special Relativity Theory (SRT) are thoroughly re-examined from an operational point of view, with particular emphasis on the status of Einstein synchronization in the light of the possibility of arbitrary synchronization procedures in inertial reference frames. Once correctly and explicitly phrased, the principles of SRT allow for a wide range of “theories” that differ from the standard SRT only for the difference in the chosen synchronization procedures, but are wholly equivalent to SRT in predicting empirical facts. (...) This results in the introduction, in the full background of SRT, of a suitable synchronization gauge. A complete hierarchy of synchronization gauges is introduced and elucidated, ranging from the useful Selleri synchronization gauge (which should lead, according to Selleri, to a multiplicity of theories alternative to SRT) to the more general Mansouri–Sexl synchronization gauge and, finally, to the even more general Anderson–Vetharaniam–Stedman’s synchronization gauge. It is showed that all these gauges do not challenge the SRT, as claimed by Selleri, but simply lead to a number of formalisms which leave the geometrical structure of Minkowski spacetime unchanged. Several aspects of fundamental and applied interest related to the conventional aspect of the synchronization choice are discussed, encompassing the issue of the one-way velocity of light in inertial and rotating reference frames, the global positioning system (GPS)’s working, and the recasting of Maxwell equations in generic synchronizations. Finally, it is showed how the gauge freedom introduced in SRT can be exploited in order to give a clear explanation of the Sagnac effect for counter-propagating matter beams. (shrink)

In this paper we examine Ellis and Bowman's argument, that simultaneity in inertial frames of reference is not conventional, from the axiomatic point of view. In Part I we examine the role of conventions in an axiomatic physical theory, and in Part II the relation of simultaneity in Reichenbach's axiomatization of the space-time theory of special relativity.

This paper explores early Australasian philosophy in some detail. Two approaches have dominated Western philosophy in Australia: idealism and materialism. Idealism was prevalent between the 1880s and the 1930s, but dissipated thereafter. Idealism in Australia often reflected Kantian themes, but it also reflected the revival of interest in Hegel through the work of ‘absolute idealists’ such as T. H. Green, F. H. Bradley, and Henry Jones. A number of the early New Zealand philosophers were also educated in the idealist tradition (...) and were influential in their communities, but produced relatively little. In Australia, materialism gained prominence through the work of John Anderson, who arrived in Australia in 1927, and continues to be influential. John Anderson had been a student of Henry Jones, who might therefore be said to have influenced both main strands of Australian philosophical thought. (shrink)

This chapter contains sections titled: Highlights of Past Literature Current Work Future Work.

To date, there is no universal and coherent theory concerning the nature or the function of time. Furthermore, important and unresolved controversies raging within both philosophy and the natural sciences apparently indicate that there is little hope of constructing a single, unified theory. Even so-called "folk" theories of time, embedded within different cultural traditions, show no common elements, and therefore can not provide a pre-theoretical description of time, towards which an explanatory framework could be constructed. This lack of consensus indicates (...) that the concept as it is currently being used is ill defined, and, at the very least, needs to be considerably revised. The conceptual disarray surrounding time has aided and abetted the arguments of certain thinkers, especially Ricoeur, working within the phenomenological tradition who make de principe claims that there can not be a single theory of time. My intention is not to try and to produce a concept of time that was capable of unifying all these different elements. Rather, Ricoeur's arguments and those of others working in the phenomenological tradition dissatisfied me. I believed that their arguments were informed by a myopic, muddled and positively 19th Century understanding of the scientific project. Hence, my aim is to show that Ricoeur's claim will not stand up to scrutiny, and that there are no principled arguments against the possibility of a unified theory of time. We examine the major arguments against unification in general, and also with particular reference to theories of time, such as Husserlian phenomenology, conventionalism, instrumentalism, anti-reductive positions in general, as well as the specific problem of reducing subjective experience to objective description. We demonstrate that none of these objections constitutes a watertight a priori argument against a unified theory of time. Furthermore, we demonstrate that recent developments in the philosophy of science and the philosophy of mind have made such a unified theory a plausible goal. We argue that post-positivist philosophy of science, with its emphasis on research programmes, the co-evolution of theories and super-empirical rational support, opens the way for new types of evidence to be brought to bear on questions about time. Also, recent developments in the brain sciences mean that a neurologically plausible and fully naturalised analysis of our experience of time is being developed. Although much work in this direction has begun, we argue that it is fragmented, partly through the limitations of our current knowledge, but more particularly through an inadequate background of coherent philosophical thought. This has lead both philosophers and scientists to attempt grand metaphysical answers to muddled philosophical questions which threaten the progress which natural science and the philosophy of science have offered in the second half of the twentieth 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 ain't nuthin' until I call it.”Bill Guthrie, UmpireNumerous criticisms of Adolf Grünbaum's account of conventions in physics have been published, and he has replied to most of them. Nonetheless, there seem to me to be good reasons for offering further criticism. In the first place Grünbaum's philosophy seems to me at least partly an extrapolation of one aspect of the views on conventions developed by Reichenbach and others. Since I think many of the issues which Reichenbach attempted to settle (...) in his various discussions of conventions in physics are genuine and important, and I also think that those aspects of his views on which Grünbaum has focused are among the least satisfactory, it seems important to suggest questions and answers about conventions in physics which may develop more satisfactory Reichenbachian themes. Secondly, Grünbaum's philosophy centers on a distinction, that between extrinsic and intrinsic properties and relations, which has never been made satisfactorily clear either by Grünbaum or by his critics. Until it is clarified we will remain unsure of just what he is claiming and why we should think it true or think it false. Finally, Grünbaum's replies to his critics, especially his most recent reply, [9], involve unusually important claims which fail to be buttressed by the arguments he gives. I have in mind such claims as that we can learn something important about the ontological status of properties and relations by examining descriptions of them, that on the most straightforward and literal interpretation, the general theory of relativity is inconsistent, and that the foremost advocates of geometrodynamics, Clifford and Wheeler, were and are enmeshed in contradiction. My own view is that all of these claims are dubious or false, but I shall be less concerned with establishing their falsity than with discrediting the arguments offered for them. (shrink)

In this paper we describe a propagation experiment to measure the one-way velocity of electromagnetic radiation. The experiment utilizes the rotation of the earth to interchange the positions of two rubidium vapor frequency standards over12 h, thereby canceling initial clock phase differences. It is demonstrated that although the drift characteristics of modern rubidium atomic clocks may be large for long-term absolute timing requirements, the short-term random fluctuations are small. It is found that over a24-h period, the long-term drift can be (...) accurately parameterized in retrospect and removed, thereby permitting the detection of temporal variations less than1 nsec in magnitude. With coherent summing techniques this value may be significantly reduced, and it becomes realistic to consider an experiment where the clocks are separated by distances of the order of several hundreds of meters in order to detect velocities of the order of that of the solar system with respect to the center of the galaxy(≈10 5 m sec −1 ), thus ensuring that the rotational motion of the earth has a negligible effect in altering the relative inertial characteristics of the reference frames of each clock. It is demonstrated that under such conditions the measurement of the one-way speed of propagation of electromagnetic radiation is not only meaningful, but can be simply implemented with commercially available instrumentation. (shrink)

There are two main camps in 20th-century philosophy of time: A-theorists who believe in the dynamic model of reality, and B-theorists who maintain a static model of reality. After the publication of Putnam’s influential article, “time and physical geometry”, the implications of the Special Theory of Relativity became serious in metaphysical discussions about temporal reality. Some philosophers argued that this theory contradicts the dynamic model and implies the ontology of the static model, namely, the objective reality of the present, past (...) and future events. In response, some advocates of the dynamic model argued that there can be dynamic models in relativistic setting, though they are different, radically, from old theories of dynamic reality. In this paper, first, I shall discuss how special relativity contradicts the traditional dynamic model and, then, how new dynamic models imply a relative concept of reality, in contrast to its old absolute concept and, so, why these strategies are very unintuitive. Finally, I shall argue that this radical conceptual shift about reality is, not only unintuitive, but unwarranted and, in some sense, inconsistent as well. (shrink)

Philosophy and Literature is an internationally renowned refereed journal founded by Denis Dutton at the University of Canterbury, Christchurch. It is now published by the Johns Hopkins University Press. Since its inception in 1976, Philosophy and Literature has been concerned with the relation between literary and philosophical studies, publishing articles on the philosophical interpretation of literature as well as the literary treatment of philosophy. Philosophy and Literature has sometimes been regarded as iconoclastic, in the sense that it repudiates academic pretensions, (...) insidious jargon and institutional vogue. Dutton, who remains the editor, still writes a regular column. A distinctive feature of Philosophy and Literature was the annual Bad Writing Contest, held from 1995–98, which sought to identify (and publish) the ‘most stylistically lamentable passages’ of academic prose, often to great amusement. (shrink)

A clock-transport method of synchronization employing proper time is described that yields in any given inertial system the same result as slow transport, but that imposes no limit on transport proper speed. It is argued that because the method involves only the empirically validated kinematic invariant proper time, on which all observers must agree, there exists an option to synchronize clocks in such a way that thesimultaneity of spatially separated events is agreed upon by all observers, hence is “absolute.” Such (...) agreement refers only to phase equality of members (present at the events judged simultaneous) of comoving clock sets, not to clock rates or clock phase numerical values in different inertial systems. The demonstration employs only the on-worldline assertions of Einstein's kinematics. It thus depends on a limited subset of his ideas and allows a different identification of the spacelike invariant. (shrink)

This paper is a response to the "panel discussion of simultaneity by slow clock transport in the special and general theories of relativity" ("philosophy of science", 36, (march, 1969), Pp. 1-81) which arose out of a paper by brian ellis and peter bowman on "conventionality in distant simultaneity", ("philosophy of science", 34, (june, 1967), Pp. 116-36). It is argued that the basic disagreement between the pittsburgh panel and us is an epistemological one. In particular, Our concept of a good physical (...) reason is radically different from the pittsburgh panel's. For us the known existence of a number of concordant, Isotropic, And logically independent criteria for distant simultaneity, And the non-Existence of any known discordant but isotropic criteria for distant simultaneity is a good physical reason for choosing one of these criteria. For the pittsburgh panel it is not. (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)

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)

After describing a new method of synchronizing spatially separated clocks by means of clock transport, this paper discusses the philosophical import of the existence of such methods, including those of Ellis and Bowman and of Bridgman, with special reference to the Ellis-Bowman claim that "the thesis of the coventionality of distant simultaneity... is thus either trivialized or refuted." I argue that the physical facts do not support this philosophical conclusion, and that a substantial part of their argument against Reichenbach, in (...) particular, is misdirected. Finally, I suggest that Ellis and Bowman employ seriously unclear notions of triviality and "good physical reasons" that tend to obscure rather than clarify the basic philosophical issues. An objective criterion of nontriviality of conventions is advanced. (shrink)

The convention that the one-way velocity of light is isotropic is shown to be independent of the postulates of relativity in a globally Minkowskian continuum, but not in a continuum which is only locally Minkowskian.

A number of physical processes and experimental procedures are listed which appear to be inexplicable in the context of the conventionality thesis of Reichenbach and Grünbaum. Distant synchrony can be produced by procedures based on the free displacement or rotation of elastic solids. Results are expected to agree with Einstein's definition of distant synchrony (by means of light signals, assuming isotropy). The one-way velocity of light can be measured using a rotating shaft, slotted disks, and one stationary clock.

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)

The Conventionality of Simultaneity espoused by Reichenbach, Grunbaum, Edwards, and Winnie is herein extended to mechanics and electrodynamics. The extension is seen to be a special case of a generally covariant formulation of physics, and therefore consistent with Special Relativity as the geometry of flat space-time. Many of the quantities of classical physics, such as mass, charge density, and force, are found to be synchronization dependent in this formulation and, therefore, in Reichenbach's terminology, "metrogenic." The relationship of these quantities to (...) 4-vectors and their physical significance is discussed. (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)

The demonstration that slow transport of clocks can be used to define simultaneity in inertial frames of reference leads to the question of whether clock transport can similarly be used in noninertial frames. It is shown that there are certain types of reference frames in which the clock-transport method cannot be used in a self-consistent manner. It is also shown that there are other types of noninertial frames in which the clock-transport method will succeed. The discussion includes noninertial frames in (...) flat space-time as well as the case of curved space-times. (shrink)

Beauregard claims that Bowman and I were mistaken in saying that “… if the empirical predictions of the Special Theory regarding clock transport are correct, [then] a slow transport definition of simultaneity can be constructed that is logically independent of any signal definition, but is in fact equivalent to the standard signal definition” His objection is not to the empirical concordance of the two criteria, but to the claim that the two are logically independent. His argument is that we fail (...) to take account of Winnie's Passage Time Principle, and that if due account is taken of this principle, then “the concordance between the two criteria is logically guaranteed by the synchrony-free factual core of the STR”. However, one cannot show that A is not logically independent of B by showing that it is not independent of B and C. Hence, Beauregard's argument fails against the quoted passage. (shrink)

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)

The objective of this article is to provide a formalism to deal with the special theory of relativity (STR, in short) as riewed by Reichenbach, according to which STR involves an ineradicableconventionality of simultaneity. One of the two postulates of STR asserts that, in empty space, the one-way speed of light relative to inertial frames is constant. Experimental evidence, however, is related to the constancy of the round-trip speed of light and has no bearing on one-way speeds. Following Reichenbach's viewpoint, (...) we relax the second postulate of STR, abandoning the constancy of the one-way speed of light to the more realistic one asserting the constancy of the round-trip speed of light. This, in turn, results in a formalism to deal with Reichenbach's special theory of relativity (RSTR, in short) in which the two one-way speeds of light in empty space, C±, in the two senses of a round-trip are arbitrarily selected in such a way that their harmonic mean is the measurable round-trip speed of light, c. Experimentally, RSTR and STR are indistinguishable and, hence, represent the same physical theory. It is only the formalism that we use to deal with STR which is extended in RSTR to accommodate the immeasurability of one-way velocities. The usefulness of the proposed formalism to study special relativity is demonstrated. (shrink)

The twin paradox (i.e. the reasoning made by the traveling twin, reversing the reasoning made by the earthbound twin, by which it is he who should be older) can be resolved by taking into account the relativity of simultaneity. However, simultaneity depends on a convention about the one-way velocity of light provided that the Reichenbach-Grünbaum hypothesis, is time. So far the resolution has been presented only for the Einstein convention. We show that for all possible choices of the relevant synchronization (...) parameters the calculations performed by both twins yield the same final results when carefully taking into account the relativity of simultaneity according to the conventions they have chosen. Since the final results do not depend on any of the synchronization parameters, the Reichenbach-Grünbaum hypothesis is thereby supported. (shrink)

Reichenbach, Grünbaum, and others have argued that special relativity is based on arbitrary conventions concerning clock synchronizations. Here we present a mathematical framework which shows that this conventionality is almost equivalent to the arbitrariness in the choice of coordinates in an inertial system. Since preferred systems of coordinates can uniquely be defined by means of the Lorentz invariance of physical laws irrespective of the properties of light signals, a special clock synchronization—Einstein's standard synchrony—is selected by this principle. No further restrictions (...) conerning light signal synchronization, as proposed, e.g., by Ellis and Bowman, are required in order to refute conventionalism in special relativity. (shrink)

Thought experiments are described in which the one-way velocity of light appears as a physical quantity. A rotating shaft is used to define distant synchrony for a system of clocks along the shaft. In this context Einstein's definition of distant simultaneity is seen as based on a physical assumption (and not merely on an overwhelmingly sensible choice in a range of conventional possibilities).