Albert Einstein’s theory of General Relativity was once the leading theory in theoretical physics. Unfortunately the theory describes macroscopic reality without a clear link with the the microcosm in respect to the properties of spacetime. However the theory of General Relativity has proved to predict macroscopic phenomena in a very accurate way. Nowadays most theoretical physicists use the conceptual framework of quantum theory. So it is not surprisingly that the question about the “true nature” of spacetime becomes very (...) intrigue. (shrink)

We address the question of whether it is possible to operate a time machine by manipulating matter and energy so as to manufacture closed timelike curves. This question has received a great deal of attention in the physics literature, with attempts to prove no- go theorems based on classical general relativity and various hybrid theories serving as steps along the way towards quantum gravity. Despite the effort put into these no-go theorems, there is no widely accepted definition of a time (...) machine. We explain the conundrum that must be faced in providing a satisfactory definition and propose a resolution. Roughly, we require that all extensions of the time machine region contain closed timelike curves; the actions of the time machine operator are then sufficiently "potent" to guarantee that closed timelike curves appear. We then review no-go theorems based on classical general relativity, semi-classical quantum gravity, quantum field theory on curved spacetime, and Euclidean quantum gravity. Our verdict on the question of our title is that no result of sufficient generality to underwrite a confident "yes" has been proven. Our review of the no-go results does, however, highlight several foundational problems at the intersection of general relativity and quantum physics that lend substance to the search for an answer. (shrink)

This paper dealing with extension of the Einstein eld equations using apparatus of contemporary generalization of the classical Lorentzian geometry named in literature Colombeau distributional geometry, see for example [1], [2], [3], [4], [5], [6], [7] and [32]. The regularizations of singularities presented in some solutions of the Einstein equations is an important part of this approach. Any singularities present in some solutions of the Einstein equations recognized only in the sense of Colombeau generalized functions [1], [2] and not classically. (...) In this paper essentially new class Colombeau solutions to Einstein eld equations is obtained. The vacuum energy density of free scalar quantum field  with a distributional background spacetime also is considered. It has been widely believed that, except in very extreme situations, the influence of gravity on quantum fields should amount to just small, sub-dominant contributions. Here we argue that this belief is false by showing that there exist well-behaved spacetime evolutions where the vacuum energy density of free quantum fields is forced, by the very same background distributional spacetime such distributional BHs, to become dominant over any classical energy density component. This semiclassical gravity effect finds its roots in the singular behavior of quantum fields on curved spacetimes. In particular we obtain that the vacuum fluctuations have a singular behavior on BHs horizon. (shrink)

Gravity is the curvature of spacetime, the structural property of static gravitational field, a geometric field, in curved coordinates, according the functions guv, that express geometric relations between material events. Course, general relativity is a relational theory, however, gravity, a thinking category, has symetric physical effects with matter. We use, analitic and critic method of reread the general relativity, since the perspective of the history of the science and the philosophy of the science. Our goal is driver the (...) debate on gravity, to the arena of the quantum physics, but without the ballast of the general relativity. We find that through of relativist aether was attempted transform spacetime in a substantia without succes, the consequence was return to problematic geometric field. The philosophy of the science intervenes, and according the best philosophical theory of substantivalism, spacetime is a inmaterial, geometric substantia. Then, the metaphysics arrives to a full solution in the super-substantivalism theory, that affirms: matter arises from geometric spacetime. Thus, it explains consistently the symetric physical effects between spacetime and matter. Surely, this solution is a medieval speculation. Our conclusion is that since general relativity do not defined physically spacetime leads necessarily to philosophical definitions of relationism and substantivalism on spacetime that are unacceptable physically. Therefore, gravity is not the curvature of spacetime. (shrink)

I present a discussion of some issues in the ontology of spacetime. After a characterisation of the controversies among relationists, substantivalists, eternalists, and presentists, I offer a new argument for rejecting presentism, the doctrine that only present objects exist. Then, I outline and defend a form of spacetime realism that I call event substantivalism. I propose an ontological theory for the emergence of spacetime from more basic entities. Finally, I argue that a relational theory of pre-geometric entities (...) can give rise to substantival spacetime in such a way that relationism and substantivalism are not necessarily opposed positions, but rather complementary. In an appendix I give axiomatic formulations of my ontological views. (shrink)

Important features of space and time are taken to be missing in quantum gravity, allegedly requiring an explanation of the emergence of spacetime from non-spatio-temporal theories. In this paper, we argue that the explanatory gap between general relativity and non-spatio- temporal quantum gravity theories might significantly be reduced with two moves. First, we point out that spacetime is already partially missing in the context of general relativity when understood from a dynamical perspective. Second, we argue that most approaches (...) to quantum gravity already start with an in-built distinction between structures to which the asymmetry between space and time can be traced back. (shrink)

When a theory, as the general relativity, linked to special relativity, is foundation of a scientific paradigm, through normal science and academy, scientifics, professionals, professors, students and journals of that scientific community, the paradigm, it self-sustains and reproduces. Thus, the research is obligated and limited to apply the model existent of the paradigm to formulate problems and solve them, without searching new discoveries. This self-protection of the paradigm causes it to end its cycle of life, only after a long time, (...) until that arise unresolved anomalies, some presents since origin, that they finally cause its change by other new paradigm. In this work, we study the most important anomalies that are part of the foundations of general relativity with the goal of promoting the call period of transition that is previous to scientific revolution. We use critical analysis method for rereading the general relativity, from the perspective of the history of science and philosophy of science. We find, the structural and complex anomaly of general relativity based on metaphysical spacetime that produces the metaphysics replaces physics. Also, two internal anomalies their direct consequences. These are: matter curves metaphysical spacetime, and metaphysical spacetime determines the geodesic motion of physical matter. We conclude that general relativity has no valid physical concept of spacetime, therefore of gravity. For these reasons, a new paradigm is needed. (shrink)

This paper assesses branching spacetime theories in light of metaphysical considerations concerning time. I present the A, B, and C series in terms of the temporal structure they impose on sets of events, and raise problems for two elements of extant branching spacetime theories—McCall’s ‘branch attrition’, and the ‘no backward branching’ feature of Belnap’s ‘branching space-time’—in terms of their respective A- and B-theoretic nature. I argue that McCall’s presentation of branch attrition can only be coherently formulated on a (...) model with at least two temporal dimensions, and that this results in severing the link between branch attrition and the flow of time. I argue that ‘no backward branching’ prohibits Belnap’s theory from capturing the modal content of indeterministic physical theories, and results in it ascribing to the world a time-asymmetric modal structure that lacks physical justification. (shrink)

The General Relativity understands gravity like inertial movement of the free fall of the bodies in curved spacetime of Lorentz. The law of inertia of Newton would be particular case of the inertial movement of the bodies in the spacetime flat of Euclid. But, in the step, from general to particular, breaks the law of inertia of Galilei since recovers apparently the rectilinear uniform movement but not the repose state, unless the bodies have undergone their collapse, although, (...) the curved spacetime becomes flat and the curved geodesies becomes straight lines. For General Relativity is a natural law, within of a gravitational field, the accelerated movement of the bodies, that leads to that a geometric curvature puts out to the bodies in such geodesic movement. In this paper this error of General Relativity, like generalization of the law of inertia of Galilei, is examined and it is found that it is caused by suppression of mass and force that allows conceiving acceleration like property of spacetime. This is a mathematical and non-ontological result. Indeed, mass and force are the fundament that the gravitational acceleration is independent of the magnitude of mass of the bodies but gravity not of the mass and the gravitational force. The action of the gravity force, on inertial and gravitational masses of a body, produces mutual cancellation during its free fallen but too its weight when this cease. By means of the third law of Newton it shows that gravity is a force since weight is caused by gravity. (shrink)

Eleanor Knox has argued that our concept of spacetime applies to whichever structure plays a certain functional role in the laws (the role of determining local inertial structure). I raise two complications for this approach. First, our spacetime concept seems to have the structure of a cluster concept, which means that Knox's inertial criteria for spacetime cannot succeed with complete generality. Second, the notion of metaphysical fundamentality may feature in the spacetime concept, in which case (...) class='Hi'>spacetime functionalism may be uninformative in the absence of answers to fundamental metaphysical questions like the substantivalist/relationist debate. (shrink)

The General Relativity understands gravity like inertial movement of the free fall of the bodies in curved spacetime of Lorentz. The law of inertia of Newton would be particular case of the inertial movement of the bodies in the spacetime flat of Euclid. But, in the step, of the particular to the general, breaks the law of inertia of Galilei since recovers the rectilinear uniform movement but not the repose state, unless the bodies have undergone their union, (...) although, the curved spacetime becomes flat and the curved geodesies becomes straight lines. For General Relativity is a natural law, within of a gravitational field, the uniform accelerated movement of the bodies, that leads to that a geometric curvature puts out to the bodies of the repose state for animate them of the movement of free fallen. In this paper this error of General Relativity, like generalization of the law of inertia of Galilei, is examined and it is found that it is caused by suppression of mass and force that allows conceiving acceleration like property of spacetime. This is a mathematical and non-ontological result. Indeed, mass and force are the fundament that the gravitational acceleration is a constant value for all the bodies, independently of the magnitude of mass but not of the mass and the gravitational force. The action of the gravity force, on inertial and gravitational masses of a body, produces mutual cancellation during its free fallen. In addition, by means of the third law of Newton it demonstrates that gravity is a force since weight is caused by gravity force. (shrink)

This essay examines the underdetermination problem that plagues structuralist approaches to spacetime theories, with special emphasis placed on the epistemic brands of structuralism, whether of the scientific realist variety or not. Recent non-realist structuralist accounts, by Friedman and van Fraassen, have touted the fact that different structures can accommodate the same evidence as a virtue vis-à-vis their realist counterparts; but, as will be argued, these claims gain little traction against a properly constructed liberal version of epistemic structural realism. Overall, (...) a broad construal of spacetime theories along epistemic structural realist lines will be defended which draws upon both Friedman’s earlier work and the convergence of approximate structure over theory change, but which also challenges various claims of the ontic structural realists. (shrink)

This essay is a contribution to the historical phenomenology of science, taking as its point of departure Husserl’s later philosophy of science and Jacob Klein’s seminal work on the emergence of the symbolic conception of number in European mathematics during the late sixteenth and seventeenth centuries. Sinceneither Husserl nor Klein applied their ideas to actual theories of modern mathematical physics, this essay attempts to do so through a case study of the conceptof “spacetime.” In §1, I sketch Klein’s account (...) of the emergence of the symbolic conception of number, beginning with Vieta in the late sixteenth century. In §2,through a series of historical illustrations, I show how the principal impediment to assimilating the new symbolic algebra to mathematical physics, namely, thedimensionless character of symbolic number, is overcome via the translation of the traditional language of ratio and proportion into the symbolic language of equations. In §§3–4, I critically examine the concept of “Minkowski spacetime,” specifically, the purported analogy between the Pythagorean distance formula and the Minkowski “spacetime interval.” Finally, in §5, I address the question of whether the concept of Minkowski spacetime is, as generally assumed, indispensable to Einstein’s general theory of relativity. (shrink)

We consider momentum operators on intrinsically curved manifolds. Given that the momentum operators are Killing vector fields whose integral curves are geodesics, it is shown that the corresponding manifold is either flat, or otherwise of compact type with positive constant sectional curvature and dimension equal to 1, 3 or 7. Explicit representations of momentum operators and the associated Casimir element will be discussed for the 3-sphere. It will be verified that the structure constants of the underlying Lie algebra are (...) proportional to 2ħ/R, where R is the curvature radius of the sphere. This results in a countable energy and momentum spectrum of freely moving particles. It is shown that the maximum resolution of the possible momenta is given by the de-Broglie wave length λ=πR, which is identical to the diameter of the manifold. The corresponding covariant position operators are defined in terms of geodesic normal coordinates and the associated commutator relations of position and momentum are established. (shrink)

We revise the extended uncertainty relations for the Rindler and Friedmann spacetimes recently discussed by Dabrowski and Wagner in [9]. We reveal these results to be coordinate dependent expressions of the invariant uncertainty relations recently derived for general 3-dimensional spaces of constant curvature in [10]. Moreover, we show that the non-zero minimum standard deviations of the momentum in [9] are just artifacts caused by an unfavorable choice of coordinate systems which can be removed by standard arguments of geodesic completion.

According to a number of approaches in theoretical physics, spacetime does not exist fundamentally. Rather, spacetime exists by depending on another, more fundamental, non-spatiotemporal structure. A prevalent opinion in the literature is that this dependence should not be analyzed in terms of composition. We should not say, that is, that spacetime depends on an ontology of non-spatiotemporal entities in virtue of having them as parts. But is that really right? On the contrary, we argue that a mereological (...) approach to dependent spacetime is not only viable, but promises to enhance our understanding of the physical situation. (shrink)

The existence and fundamentality of spacetime has been questioned in quantum gravity where spacetime is frequently described as emerging from a more fundamental non-spatiotemporal ontology. This is supposed to lead to various philosophical issues such as the problem of empirical coherence. Yet those issues assume beforehand that we actually understand and agree on the nature of spacetime. Reviewing popular conceptions of spacetime, we find that there is substantial disagreement on this matter, and little hope of resolving (...) it. However, we argue that this should not trouble us as these issues, which seem to suggest the need for an account of spacetime in quantum gravity, can be addressed without one. (shrink)

Several different quantum gravity research programmes suggest, for various reasons, that spacetime is not part of the fundamental ontology of physics. This gives rise to the problem of empirical coherence: if fundamental physical entities do not occupy spacetime or instantiate spatiotemporal properties, how can fundamental theories concerning those entities be justified by observation of spatiotemporally located things like meters, pointers and dials? I frame the problem of empirical coherence in terms of entailment: how could a non-spatiotemporal fundamental theory (...) entail spatiotemporal evidence propositions? Solutions to this puzzle can be classified as realist or antirealist, depending on whether or not they posit a non-fundamental spacetime structure grounded in or caused by the fundamental structure. These approaches place different constraints on our everyday concepts of space and time. Applying lessons from the philosophy of mind, I argue that only realism is both conceptually plausible and suitable for addressing the problem at hand. I suggest a role functionalist version of realism, which is consistent with both grounding and causation, and according to which our everyday concepts reveal something of the true nature of emergent spacetime. (shrink)

The consensus among spacetime substantivalists is to respond to Leibniz's classic shift arguments, and their contemporary incarnation in the form of the hole argument, by pruning the allegedly problematic metaphysical possibilities that generate these arguments. Some substantivalists do so by directly appealing to a modal doctrine akin to anti-haecceitism. Other substantivalists do so by appealing to an underlying hyperintensional doctrine that implies some such modal doctrine. My first aim in this paper is to pose a challenge for all extant (...) forms of this consensus position. My second aim is to show what form substantivalism must take in order to uphold the consensus while addressing this challenge. The result is a novel "plenitudinous" substantivalist view, which predicts that certain modal facts about spacetime are vague or indeterminate. I then argue against this view on independent grounds, concluding that substantivalists should reject the consensus position. The paper also discusses the way forward for substantivalists in light of this conclusion. (shrink)

In a recent article, Ned Markosian gives an argument against four-dimensionalism understood as the view that time is one of four identical dimensions that constitute a single four-dimensional manifold. In this paper, I show that Markosian attacks a straw man as his argument targets a theory known to be false on empirical grounds. Four-dimensionalism rightly conceived in no way entails that time is identical to space. I then address two objections raised by Markosian against four-dimensionalism rightly conceived.

This essay explores the possibility of constructing a structural realist interpretation of spacetime theories that can resolve the ontological debate between substantivalists and relationists. Drawing on various structuralist approaches in the philosophy of mathematics, as well as on the theoretical complexities of general relativity, our investigation will reveal that a structuralist approach can be beneficial to the spacetime theorist as a means of deflating some of the ontological disputes regarding similarly structured spacetimes.

The hole argument purports to show that all spacetime theories of a certain form are indeterministic, including the General Theory of Relativity. The argument has given rise to an industry of searching for a metaphysics of spacetime that delivers the right modal implications to rescue determinism. In this paper, I first argue that certain prominent extant replies to the hole argument—namely, those that appeal to an essentialist doctrine about spacetime—fail to deliver the requisite modal implications. As part (...) of my argument, I show that threats to determinism of the sort brought out by the hole argument are more general than has heretofore been recognized. I then use these results to propose a novel essentialist doctrine about spacetime that successfully rescues determinism, what I call sufficiency metric essentialism. However, I go on to argue that once we realize what an essentialist doctrine about spacetime must look like in order to address the hole argument, we should reject all such doctrines, because they can't fulfill their ambition of improving on standard modal replies to the argument. I close by suggesting some lessons for future work on spacetime and the metaphysics of physics more broadly, and also drawing some general morals for contemporary metaphysics, in particular about (i) whether essence can be used to articulate a precise structuralist doctrine, and (ii) the relationship between essence and modality. (shrink)

We outline a simple development of special and general relativity based on the physical meaning of the spacetime interval. The Lorentz transformation is not used.

This paper examines Descartes' problematic relational theory of motion, especially when viewed within the context of his dynamics, the Cartesian natural laws. The work of various commentators on Cartesian motion is also surveyed, with particular emphasis placed upon the recent important texts of Garber and Des Chene. In contrast to the methodology of most previous interpretations, however, this essay employs a modern "spacetime" approach to the problem. By this means, the role of dynamics in Descartes' theory, which has often (...) been neglected in favor of kinematic factors, is shown to be central to finding a solution to the puzzle of Cartesian motion. (shrink)

Several approaches to developing a theory of quantum gravity suggest that spacetime—as described by general relativity—is not fundamental. Instead, spacetime is supposed to be explained by reference to the relations between more fundamental entities, analogous to `atoms' of spacetime, which themselves are not (fully) spatiotemporal. Such a case may be understood as emergence of \textit{content}: a `hierarchical' case of emergence, where spacetime emerges at a `higher', or less-fundamental, level than its `lower-level' non-spatiotempral basis. But quantum gravity (...) cosmology also presents us with the possibility of emergence of \textit{context}: where spacetime emerges from some `prior' non-spatiotemporal state (replacing the Big Bang), due to particular conditions in the early universe. I present a general conception of emergence which is plausibly able to accommodate both pictures. This is a positive conception that does not rely on a failure of reduction or explanation in any sense (indeed, reduction is a necessary feature of quantum gravity, and is useful in understanding emergence in this case). I also consider the possibility that the distinction between content- and context- based explanations is blurred, or usefully `collapsed', in the case of spacetime emergence. (shrink)

The purpose of this paper is twofold. First, we will observe how May’s background in astrophysics influenced Queen's lyrics, such as 'Don't Stop Me Now' or 'Dead on Time'. Our goal is to see how physical and philosophical concepts of matter and time intersect with the common understanding of such phenomena, and how they differ from them. Second, we will focus on usually not that well-known song ‘39, which shows the entire point of the special theory of relativity through a (...) prism of storytelling. Concepts of space and time will be analyzed from both absolute and relative perspectives, connecting them to historical theories of space and time. (shrink)

Notoriously, the Einstein equations of general relativity have solutions in which closed timelike curves occur. On these curves time loops back onto itself, which has exotic consequences: for example, traveling back into one's own past becomes possible. However, in order to make time travel stories consistent constraints have to be satisfied, which prevents seemingly ordinary and plausible processes from occurring. This, and several other "unphysical" features, have motivated many authors to exclude solutions with CTCs from consideration, e.g. by conjecturing a (...) chronology protection law. In this contribution we shall investigate the nature of one particular class of exotic consequences of CTCs, namely those involving unexpected cases of indeterminism or determinism. Indeterminism arises even against the backdrop of the usual deterministic physical theories when CTCs do not cross spacelike hypersurfaces outside of a limited CTC-region|such hypersurfaces fail to be Cauchy surfaces. We shall compare this CTC-indeterminism with four other types of indeterminism that have been discussed in the philosophy of physics literature: quantum indeterminism, the indeterminism of the hole argument, non-uniqueness of solutions of differential equations and lack of predictability due to insuffcient data. By contrast, a certain kind of determinism appears to arise when an indeterministic theory is applied on a CTC: things cannot be different from what they already were. Again we shall make comparisons, this time with other cases of determination in physics. We shall argue that on further consideration both this indeterminism and determinism on CTCs turn out to possess analogues in other, familiar areas of physics. CTC- indeterminism is close to the epistemological indeterminism we know from statistical physics, while the "fixedness" typical of CTC-determinism is pervasive in physics. CTC- determinism and CTC-indeterminism therefore do not provide incontrovertible grounds for rejecting CTCs as conceptually inadmissible. (shrink)

We define and develop a notion of spacetime that incorporates both McTaggart's A-series and his B-series that is consistent with special relativity. This 'McTaggartian spacetime' or 'AB-spacetime' requires *five* not *4* variables. The interface of two AB-spacetimes from different *ontological perspectives* is quantum mechanical. This note concentrates on the physics and not the philosophy. This is an invitation to contribute to a theory that is a work in progress.

Mechanisms for QoS provisioning in communication networks range from flow-based resource reservation schemes, providing QoS guarantees, through QoS differentiation based on reservation aggregation techniques to adaptation of applications, compensating for incomplete reservations. Scalable, aggregation-based reservations can also be combined with adaptations for a more flexible and robust overall QoS provisioning. Adaptation is particularly important in wireless networks, where reservations schemes are more difficult to realize. It is widely accepted that usability of Cellular or Mobile IP can be largely improved if (...) adaptation is incorporated. Adaptation, in turn, depends on coding techniques involved and on user requirements. Those impose certain preferences and ordering relations on QoS hierarchies or degradation paths to be followed along when adaptation is performed. With the advent of MPEG4 coding techniques, more sophisticated adaptation schemes are more likely to be supported in the future. (shrink)

The present volume collects essays on the philosophical foundations of quantum theories of gravity, such as loop quantum gravity and string theory. Central for philosophical concerns is quantum gravity's suggestion that space and time, or spacetime, may not exist fundamentally, but instead be a derivative entity emerging from non-spatiotemporal degrees of freedom. In the spirit of naturalised metaphysics, contributions to this volume consider the philosophical implications of this suggestion. In turn, philosophical methods and insights are brought to bear on (...) the foundations of quantum gravity itself. For instance, the idea of functionalism, borrowed from the philosophy of mind and discussed by several essays, exemplifies this mutual interaction the collection seeks to foster. (shrink)

This paper explores the physical and metaphysical implications of time travel, focusing on the possibility of changing the past, through a comparative analysis of David Lewis' modal realism and Everett's many-worlds interpretation of quantum mechanics. The existence of closed timelike curves (CTCs) in certain solutions to Einstein's field equations provides a theoretical basis for the possibility of backwards time travel, but this leads to a range of paradoxes, most notably the grandfather paradox. David Lewis argues that time travel must maintain (...) consistency and that the past cannot be changed, even if time travel were possible. His view is supported by his modal realism, which posits the existence of a plurality of possible worlds. In contrast, Everett's many-worlds interpretation, which holds that quantum mechanics describes a multiverse of branching realities, might seem to allow for the possibility of multiple, inconsistent histories. By examining these two ontological frameworks, this paper aims to shed light on the paradoxes of time travel and to explore whether the many-worlds interpretation provides a more satisfactory resolution to these paradoxes than Lewis' modal realism. It is argued that while Lewis' view provides a coherent model for maintaining consistency in time travel, Everett's interpretation may offer a more physically grounded and philosophically compelling account of the metaphysics of time travel. The paper concludes by suggesting that the many-worlds interpretation, by locating the branching of timelines within the structure of quantum mechanics itself, may provide a more promising framework for understanding the possibility and implications of time travel than Lewis' modal realism. However, significant questions remain about the nature of personal identity and free will in a branching multiverse. This comparative analysis aims to contribute to the ongoing debate about the metaphysical possibility of time travel and to highlight the value of engaging with interpretations of quantum mechanics in this context. Keywords: time travel, closed timelike curves, modal realism, many-worlds interpretation, grandfather paradox, metaphysics of time. (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)

Can green growth policies help protect the environment while keeping the industry growing and infrastructure expanding? The City of Kitakyushu, Japan, has actively implemented eco-friendly policies since 1967 and recently inspired the pursuit of sustainable development around the world, especially in the Global South region. However, empirical studies on the effects of green growth policies are still lacking. This study explores the relationship between road infrastructure development and average industrial firm size with air pollution in the city through the Environmental (...) Kuznets Curve (EKC) hypothesis. Auto-Regressive Distributed Lag (ARDL) and Non-linear Auto-Regressive Distributed Lag (NARDL) methods were applied on nearly 50-years’ time series data, from 1967 to 2015. The results show that the shape of the EKC of industrial growth, measured by average firm size, depends on the type of air pollution: inverted N-shaped relationships with NO2 and CO, and the U-shaped relationships with falling dust particle and Ox. Regarding infrastructure development, on the one hand, our analysis shows a positive effect of road construction on alleviating the amount of falling dust and CO concentration. On the other hand, the emissions of NO2 and Ox are shown to rise when plotted against road construction. The decline of CO emission, when plotted against both industrial growth and road development, indicates that the ruthlessness of the local government in pursuing green growth policies is effective in this case. However, the story is not straightforward when it comes to other air pollutants, which hint at limits in the current policies. The case of Kitakyushu illustrates the complex dynamics of the interaction among policy, industry, infrastructure, and air pollution. It can serve as an important reference point for other cities in the Global South when policies are formed, and progress is measured in the pursuit of a green economy. Finally, as an OECD SDGs pilot city and the leading Asian green-growth city, policymakers in Kitakyushu city are recommended to revise the data policy to enhance the findability and interoperability of data as well as to invest in the application of big data. (shrink)

The developing body of empirical work on the "Gettier effect" indicates that, in general, the presence of a Gettier-type structure in a case makes participants less likely to attribute knowledge in that case. But is that a sufficient reason to diverge from a JTB theory of knowledge? I argue that considerations of good model selection, and worries about noise and overfitting, should lead us to consider that a live, open question. The Gettier effect is perhaps so transient, and so sensitive (...) to other, epistemologically-inappropriate factors, that it raises the question of whether it ought to be counted as something to include in our theories -- or as a piece of noise to be excluded from them. (shrink)

This paper responds to Friend’s (2023) critique of the Powers-BSA, a view according to which laws of nature are efficient descriptions of how modally laden properties (powers) are possibly distributed in spacetime. In the course of this response, the paper discusses the nature of scientific and metaphysical explanation, the aim of science and the structure of modal space.

This book deals with Colombeau solutions to Einstein field equations in general relativity: Gravitational singularities, distributional SAdS BH spacetime-induced vacuum dominance. This book covers key areas of Colombeau nonlinear generalized functions, distributional Riemannian, geometry, distributional schwarzschild geometry, Schwarzschild singularity, Schwarzschild horizon, smooth regularization, nonsmooth regularization, quantum fields, curved spacetime, vacuum fluctuations, vacuum dominance etc. This book contains various materials suitable for students, researchers and academicians of this area.

I begin by giving reasons to accept the block-universe view, the strongly supported by physics view that we live in a four-dimensional world. According to it, the past and the future are as real as the present. As a result, it seems that the future is determined in the sense that what will be the case will necessarily be the case. In the dissertation, I examine whether we have to accept this consequence. I show that we do not have to (...) bite the bullet: the future might be both real and contingent. I first start to consider modal realism (possible futures are real) as a possible solution. However, I propose then another account, actualist (positing the reality of only one possible world: the space-time we live in). This solution relies on a conventionalist theory about metaphysical modality (Sidelle, 1989). It states that modal modality is purely conventional. In combination with a realist interpretation of natural modality (causal and/or nomological), this framework allows me to propose that the future is conventionally closed and naturally contingent. In this view, the necessity of the future holds in virtue of linguistic conventions and then is conventionally necessary. But this is a distinct phenomenon from the natural contingency of the future: the future is naturally contingent because there are mind-independent probabilistic relations holding between the present and the future. This solution has strong consequences: most importantly, an anti-realist view about ordinary objects and physical particles. I end up by presenting and arguing in favour of the general image of the world that comes out from these views. (shrink)

Based on the Russian school of Logunov and others, with the contribution of Tom van Flandern, and his previous works on space-time, gravitational waves and speed of the gravity, the author discusses the theory of the time-space fluid that results from the supposed gravitational waves that would have detected LIGO, and reaffirms the space-time as a structural geometric property of the dynamic matter (radiation, matter and quantum vacuum), now with the strong argument that without escape, in an unnatural way, the (...) physicists and philosophers of science confer the conception of the author to that ridiculous material-space-time, while depriving Matter, of the intrinsic space-time. In addition, he warns about the conceptual contradiction existing between NASA and Caltech over gravitational waves, being absurd the concept of Caltech, operator of LIGO, since gravitational waves would propagate in five non-detectable dimensions. NASA valiant and validly recognizes that they would be waves of space; therefore, there are no space-time waves that correspond to gravitational waves that, according to the great current of relativistic physicists, would exist. Finally, the author reaffirms that the quadrupole waves detected by LIGO are waves of the quantum vacuum. (shrink)

In this essay the author overcomes the theoretical contradiction between General Relativity that defines the gravitational field as a geometric aspect of spacetime, either as potential or curvature, and Quantum Gravity that defines it as a fundamental force of interaction, with the change in the conception of spacetime of structural geometric property from the gravitational field, to the conception of spacetime structural geometric property of matter in motion. Spacetime is not a continent of matter (Substantialism) but (...) rather is contained in matter insofar as it constitutes the geometric structure that gives it its shape and allows its changes, to which as space it confers its ability to contain and as time its capacity to becoming. Nor is spacetime the category of geometric relations of material bodies and their events (Relationism), since it is not a relational property of matter but rather the geometric spacetime structural property of matter, which it endows with their abilities to self-contain and transform. The author's conception of spacetime is that dynamic energy-matter, geometrically endowed with the four dimensions of spacetime, is spatially self-contained and temporarily self-transforming. The wave-particle, of matter and of the field, does not exist in spacetime, but this is the intrinsic structural geometric property of the wave-particle, therefore, attached to its own internal nature, as its intrinsic dimensional geometric property which with the force of law is manifested in its quantitative measurements, either when the wave particle itself is taken or in relation to others. Thus, only theories on gravity from Quantum Gravity are possible, although they must be reformulated, renouncing to integrate them with the geometric vision derived from the equations of the so-called "General Relativity". (shrink)

In this paper I argue that the debate between the so-called “presentists” – according to whom only the present is real – and the “eternalists”, according to whom past present and future are equally real, has no ontological significance. In particular, once we carefully distinguish between a tensed and a tenseless sense of existence, it is difficult to find a single ontological claim on which the two parties could disagree. Since the choice of using a tense or a tenseless language (...) is dictated by purely pragmatic reasons, we should abstain from bringing to bear pseudo-debates generated by the “tensed” or the “tenseless theories” of time on the question of understanding the philosophical implications of contemporary spacetime theories, or notions like becoming, change and persistence in time. (shrink)

Spacetime and motion are interconnected concepts. A better understanding of motion leads to a better understanding of spacetime. We use the historical critical analysis of the various theoretical proposals on motion in search of clues ignored. The prediction of the general relativity that the motion occurs in the static gravitational field is not valid because the motion always occurs in a given medium as vacuum, atmosphere, water, etc. The concept of motion and the equations of the special and (...) general relativity, as the theory of Galilee-Newton reduce motion elements to particle and spacetime. In this paper, we present the medium (in special, the quantum vacuum), as the third essential element of motion, inseparable of spacetime since it is its material support of which the spacetime is its structural form, and we analyse its consequences in the theories of spacetime. Our contribution is declare, that the spacetime itself does not exist, or is a relational property of matter, but a structural property of matter. (shrink)

Here we discuss and hope to solve a problem rooted in the necessity of the study of historical science, the slow deviation of physics education over the past century, and how the loss of crucial contextual tool has debilitated discussion of a very important yet specialized physics sub-topic: the isotropy of the one-way speed of light. Most notably, the information that appears to be most commonly missing is not simply the knowledge of the historical fact that Poincare and Lorentz presented (...) a mathematically equivalent representation of relativity theory contemporary with Einstein’s publication, but the most deleterious outcome is a lack of understanding of how that theory worked within a mechanical wave system to give the same results in all known experiments via an instrumentation-based illusion. Unfortunately those well educated in relativity theory, often haven’t been granted the advantage of contrast this history of development of the theory gives and thus some of the most direct and critical implications of modern theory are often lost on even graduate students. Chief among the implications that should be trivial to a student of relativity is the incompatibility of a mechanical wave concept of light with the modern assumptions of relativity. However, one should also be able to expect a graduate student to also easily comprehend the mathematical necessity of conjoining space with time is only descended from the presumption of isotropic constancy specifically, and further that the mechanics are one and the same as the relativity of simultaneity. However, many published papers appear to lack this understanding. The result is that the modern consensus appears to have arrived at the conclusion that the one-way speed of light is intrinsically untestable and therefore the physics community has accidentally pushed Minkowski spacetime, and most directly, the relativity of simultaneity, into the domain of pseudoscience, leaving only the historical relativistic “ether” described by Mansouri-Sexl test theory (AKA Lorentz Ether Theory) as the only workable alternative. This situation must be re-examined at the lowest possible level to arrive at an appropriate experimental regime. (shrink)

One of the greatest achievements of modern physics is the discovery of spacetime by Hermann Minkowski. Still, talking about the ”discovery” of spacetime cannot be done without further questioning its ontological status. Did Minkowski discover a real physical substrate? What is the creative role of his scientific imagination in the process of discovery? To what extent the explanatory power of spacetime supports the conclusion that it is a true description of the physical world? I consider those questions (...) in that paper, and I claim that for Minkowski’s discovery of spacetime, imagination and explanation work together in a fictionalist strategy. I explain why there is no reason to doubt the veracity of the discovery of spacetime and its physical reality. (shrink)

While the philosophers of science discuss the General Relativity, the mathematical physicists do not question it. Therefore, there is a conflict. From the theoretical point view “the question of precisely what Einstein discovered remains unanswered, for we have no consensus over the exact nature of the theory 's foundations. Is this the theory that extends the relativity of motion from inertial motion to accelerated motion, as Einstein contended? Or is it just a theory that treats gravitation geometrically in the (...) class='Hi'>spacetime setting?”. “The voices of dissent proclaim that Einstein was mistaken over the fundamental ideas of his own theory and that their basic principles are simply incompatible with this theory. Many newer texts make no mention of the principles Einstein listed as fundamental to his theory; they appear as neither axiom nor theorem. At best, they are recalled as ideas of purely historical importance in the theory's formation. The very name General Relativity is now routinely condemned as a misnomer and its use often zealously avoided in favour of, say , Einstein's theory of gravitation What has complicated an easy resolution of the debate are the alterations of Einstein's own position on the foundations of his theory”, (Norton, 1993). Of other hand from the mathematical point view the “General Relativity had been formulated as a messy set of partial differential equations in a single coordinate system. People were so pleased when they found a solution that they didn't care that it probably had no physical significance” (Hawking and Penrose, 1996). So, during a time, the declaration of quantum theorists:“I take the positivist viewpoint that a physical theory is just a mathematical model and that it is meaningless to ask whether it corresponds to reality. All that one can ask is that its predictions should be in agreement with observation.” (Hawking and Penrose, 1996)seemed to solve the problem, but recently achieved with the help of the tightly and collectively synchronized clocks in orbit frontally contradicts fundamental assumptions of the theory of Relativity. These observations are in disagree from predictions of the theory of Relativity. (Hatch, 2004a, 2004b, 2007). The mathematical model was developed first by Grossmann who presented it, in 1913, as the mathematical part of the Entwurf theory, still referred to a curved Minkowski spacetime. Einstein completed the mathematical model, in 1915, formulated for Riemann ́s spacetimes. In this paper, we present as of General Relativity currently remains only the mathematical model, darkened with the results of Hatch and, course, we conclude that a Einstein ́s gravity theory does not exist. (shrink)

This paper is a shortened version of an invited lecture held at the University of Copenhagen (Department of Anthropology) on 28 March 2019.

Einstein structured the theoretical frame of his work on gravity under the Special Relativity and Minkowski´s spacetime using three guide principles: The strong principle of equivalence establishes that acceleration and gravity are equivalents. Mach´s principle explains the inertia of the bodies and particles as completely determined by the total mass existent in the universe. And, general covariance searches to extend the principle of relativity from inertial motion to accelerated motion. Mach´s principle was abandoned quickly, general covariance resulted mathematical property (...) of the tensors and principle of equivalence inconsistent and it can only apply to punctual gravity, no to extended gravity. Also, the basic principle of Special Relativity, i.e., the constancy of the speed of the electromagnetic wave in the vacuum was abandoned, static Minkowski´s spacetime was replaced to dynamic Lorentz´s manifold and the main conceptual fundament of the theory, i.e. spacetime is not known what is. Of other hand, gravity never was conceptually defined; neither answers what is the law of gravity in general. However, the predictions arise of Einstein equations are rigorously exacts. Thus, the conclusion is that on gravity, it has only the equations. In this work it shows that principle of equivalence applies really to punctual and extended gravity, gravity is defined as effect of change of coordinates although in the case of the extended gravity with change of geometry from Minkowski´s spacetime to Lorentz´s manifold; and the gravitational motion is the geodesic motion that well it can declare as the general law of gravity. (shrink)

Albert Einstein proposed three tests of general relativity, later named the classic tests of general relativity, in 1916: the precession of the perihelion of Mercury's orbit, sun light deflection, and the gravitational redshift of the light. For gravitational testing, the indirect effects of gravity are always used, usually particles that are influenced by gravity. In the presence of gravity, the particles move along curved geodesic lines. The sources of gravity that cause the curvature of spacetime are material bodies, (...) depending on their mass. But in relativity the mass relates to the energy through the formula E = mc2, and the energy with the momentum, according to the special relativity. DOI: 10.13140/RG.2.2.25608.16648. (shrink)

Data security is, protecting data from ill- conceived get to, utilize, introduction, intrusion, change, examination, recording or destruction. Cloud computing is a sort of Internet-based computing that grants conjoint PC handling resources and information to PCs what's more, different gadgets according to necessity. It is a model that empowers universal, on-request access to a mutual pool of configurable computing resources. At present, security has been viewed as one of the best issues in the improvement of Cloud Computing. The key issue (...) in effective execution of Cloud Computing is to adequately deal with the security in the cloud applications. This paper talks about the part of cryptography in cloud computing to improve the data security. The expectation here is to get bits of knowledge another security approach with the usage of cryptography to secure information at cloud data centers. (shrink)

Utilizing Einstein’s comparison of General Relativity and Descartes’ physics, this investigation explores the alleged conventionalism that pervades the ontology of substantival and relationist conceptions of spacetime. Although previously discussed, namely by Rynasiewicz and Hoefer, it will be argued that the close similarities between General Relativity and Cartesian physics have not been adequately treated in the literature—and that the disclosure of these similarities bolsters the case for a conventionalist interpretation of spacetime ontology.

It is widely held that the influence of risk on rational decisions is not entirely explained by the shape of an agent’s utility curve. Buchak (Erkenntnis, 2013, Risk and rationality, Oxford University Press, Oxford, in press) presents an axiomatic decision theory, risk-weighted expected utility theory (REU), in which decision weights are the agent’s subjective probabilities modified by his risk-function r. REU is briefly described, and the global applicability of r is discussed. Rabin’s (Econometrica 68:1281–1292, 2000) calibration theorem strongly suggests that (...) plausible levels of risk aversion cannot be fully explained by concave utility functions; this provides motivation for REU and other theories. But applied to the synchronic preferences of an individual agent, Rabin’s result is not as problematic as it may first appear. Theories that treat outcomes as gains and losses (e.g. prospect theory and cumulative prospect theory) account for risk sensitivity in a way not available to REU. Reference points that mark the difference between gains and losses are subject to framing, many instances of which cannot be regarded as rational. However, rational decision theory may recognize the difference between gains and losses, without endorsing all ways of fixing the point of reference. In any event, REU is a very interesting theory. (shrink)