After some background setting in which it is shown how Maudlin's (1989, 1990) response to the hole argument of Earman and Norton (1987) is related to that of Rynasiewicz (1994), it is argued that the syntactic proposals of Mundy (1992) and of Leeds (1995), which claim to dismiss the hole argument as an uninteresting blunder, are inadequate. This leads to a discussion of how the responses of Maudlin and Rynasiewicz relate to issues about gauge freedom and relativity principles.

The logic of gauge theory is considered by tracing its development from general relativity to Yang-Mills theory, through Weyl's two gauge theories. A handful of elements---which for want of better terms can be called \emph{geometrical justice}, \emph{matter wave}, \emph{second clock effect}, \emph{twice too many energy levels}---are enough to produce Weyl's second theory; and from there, all that's needed to reach the Yang-Mills formalism is a \emph{non-Abelian structure group} (say $\mathbb{SU}\textrm{(}N\textrm{)}$).

In publications in 1914 and 1918, Einstein claimed that his new theory of gravity in some sense relativizes the rotation of a body with respect to the distant stars and the acceleration of the traveler with respect to the stay-at-home in the twin paradox. What he showed was that phenomena seen as inertial effects in a space-time coordinate system in which the non-accelerating body is at rest can be seen as a combination of inertial and gravitational effects in a space-time (...) coordinate system in which the accelerating body is at rest. Two different relativity principles play a role in these accounts: the relativity of non-uniform motion, in the weak sense that the laws of physics are the same in the two space-time coordinate systems involved; what Einstein in 1920 called the relativity of the gravitational field, the notion that there is a unified inertio-gravitational field that splits differently into inertial and gravitational components in different coordinate systems. I provide a detailed reconstruction of Einstein's rather sketchy accounts of the twins and the bucket and examine the role of these two relativity principles. I argue that we can hold on to but that is either false or trivial. (shrink)

Abstract Schlick quite clearly maintains that the shift from classical physics to the theories of relativity is not necessitated by experience, but motivated by the pragmatic payoff of simplifying space-time ontology. However, there is in his work another, heretofore unrecognized argument for the revolutionary shift from classical to relativistic physics. According to this conceptual line of argument, the principles that define simultaneity and motion in classical physics fail to establish a univocal correspondence to physical quantities, and therefore must be revised, (...) along with the notions of absolute space and time that they underpin. Though these insights appear only intermittently in Schlick’s work, I will seek to elaborate on them in an effort to clarify his views on conventions within physics and the nature of revolutionary science, and to suggest that these views are invulnerable to the criticisms of pragmatic empiricists such as Quine. Content Type Journal Article Pages 1-17 DOI 10.1007/s12136-011-0131-3 Authors Steven Bland, Department of Philosophy, Huron University College, 1349 Western Rd, London, Ontario, Canada N6G 1H3 Journal Acta Analytica Online ISSN 1874-6349 Print ISSN 0353-5150. (shrink)

We discuss some difficulties that arise in attempting to interpret the Page–Wootters and Internal Quantum Reference Frames formalisms, then use a ‘final measurement’ approach to demonstrate that there is a workable single-world realist interpretation for these formalisms. We note that it is necessary to adopt some interpretation before we can determine if the ‘reference frames’ invoked in these approaches are operationally meaningful, and we argue that without a clear operational interpretation, such reference frames might not be suitable to define an (...) equivalence principle. We argue that the notion of superposition should take into account the way in which an instantaneous state is embedded in ongoing dynamical evolution, and this leads to a more nuanced way of thinking about the relativity of superposition in these approaches. We conclude that typically the operational content of these approaches appears only in the limit as the size of at least one reference system becomes large, and therefore these formalisms have an important role to play in showing how our macroscopic reference frames can emerge out of wholly relational facts. (shrink)

The philosophy of physics literature contains conflicting claims on the heuristic significance of general covariance. Some authors maintain that Einstein's general relativity distinguishes itself from other theories in that it must be generally covariant, for example, while others argue that general covariance is a physically vacuous and trivial requirement applicable to virtually any theory. Moreover, when general covariance is invested with heuristic significance, that significance as a rule is assigned to so-called “active” general covariance, underwritten by the principle of background (...) independence, rather than to general covriance as Einstein understood it. While agreeing with the latter group of commentators that general covariance indeed carries heuristic significance, I argue that a background independent theory need not be generally covariant and that instead the Principle of Equivalence as Einstein understood it provides the key to understanding the heuristic power of general covariance as a “mathematical sieve” for determining the gravitational field law. However, heuristic significance accrues to general covariance only indirectly, by its encompassing the relativity of frames underwritten by Einstein's principle of equivalence. (shrink)

We review the dynamical approach to spacetime theories---in particular, its origins in the development of special relativity, its opposition to the contemporary `geometrical' approach, and the manner in which it plays out in general relativity. In addition, we demonstrate that the approach is compatible with the `angle bracket school'.

The determination of inertia by matter is looked at in general relativity, where inertia can be represented by affine or projective structure. The matter tensor T seems to underdetermine affine structure by ten degrees of freedom, eight of which can be eliminated by gauge choices, leaving two. Their physical meaning---which is bound up with that of gravitational waves and the pseudotensor t, and with the conservation of energy-momentum---is considered, along with the dependence of reality on invariance and of causal explanation (...) on conservation. (shrink)

Background independence is generally considered to be ‘the mark of distinction’ of general relativity. However, there is still confusion over exactly what background independence is and how, if at all, it serves to distinguish general relativity from other theories. There is also some confusion over the philosophical implications of background independence, stemming in part from the definitional problems. In this paper I attempt to make some headway on both issues. In each case I argue that a proper account of the (...) observables of such theories goes a long way in clarifying matters. Further, I argue, against common claims to the contrary, that the fact that these observables are relational has no bearing on the debate between substantivalists and relationalists, though I do think it recommends a structuralist ontology, as I shall endeavour to explain. (shrink)

The spacetime ontology is considered in General Relativity (GR) in view of the choice of a frame of reference (FR). Various approaches to a description of the FR, such as coordinate systems, monads and tetrads are reviewed. It is shown that any of the existing FR definitions require a preexisting background spacetime, which, if defined independently of the FR, renders the spacetime absolute in violation of the principle of relativity, or, if defined within an inertial FR (IFR), as it is (...) usually done, make the argument circular. Consequently, defining a FR in a preexisting spacetime is unacceptable. We show that a FR defines a differentiable manifold with, generally, non-Euclidean geometry. In a noninertial FR (NIFR) the observer must chose a coordinative definition either admitting existence of a universal – inertial – force or settling for non-Euclidian spacetime. Following Reichenbach, it is preferable to eliminate all universal forces and opt for a non-Euclidean geometry. It is shown that an affine connection with metric is best suited to describe the geometry of spacetime within a FR. Considering a gravitational field in an arbitrary FR, we show within the framework of Einstein’s GR that the gravity is described by nonmetricity of spacetime. This result may shed new light on the nature of the cosmological constant and dark energy. (shrink)

In this paper I argue that the positivist–conventionalist interpretation of the Restricted Principle of Relativity is flawed, due to the positivists’ own understanding of conventions and their origins. I claim in the paper that, to understand the conventionalist thesis, one has to diambiguate between three types of convention; the linguistic conventions stemming from the fundamental role of mathematical axioms (conceptual conventions), the conventions stemming from the coordination betweeh theoretical statements and physical, observable facts or entities (coordinative definitions), and conventions that (...) are made possible by possible revisions to theory (the thesis of empirical underdetermination). I claim that it is not possible to interpret the Principle of Relativity as based on one of these three types of convention. This renders the conventionalist interpretation of the Principle of Relativity untenable. The paper is part of a larger project that aims to understand the philosophical significance of the Principle of Relativity. (shrink)

Abstract The historical evolution of the principle of relativity from Galileo to Einstein is briefly traced, and purported difficulties with Einstein's formulation of the principle are examined and dismissed. This formulation is then compared to a precise version formulated recently in the geometrical language of spacetime theories. We claim that the recent version is both logically puzzling and fails to capture a crucial physical insight contained in the earlier formulations. The implications of this claim for the modern treatment of general (...) dynamical symmetries are discussed. (shrink)