Space and Time, Misc

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 spacetime functionalism may be uninformative (...) in the absence of answers to fundamental metaphysical questions like the substantivalist/relationist debate. (shrink)

[To be presented at PSA 2018] -/- The gauge/gravity duality and its relation to the possible emergence of gravity from quantum physics has been much discussed. Recently, however, Sebastian De Haro has argued that the very notion of a duality precludes emergence, given what he calls the internal view of dualities, on which the dual theories are physically equivalent. However, I argue that De Haro's argument for the internal view is not convincing, and we do not have good reasons to (...) adopt it. In turn, I propose we adopt the external view, on which dual theories are not physically equivalent, instead. (shrink)

Although Fuzzy logic and Fuzzy Mathematics is a widespread subject and there is a vast literature about it, yet the use of Fuzzy issues like Fuzzy sets and Fuzzy numbers was relatively rare in time concept. This could be seen in the Fuzzy time series. In addition, some attempts are done in fuzzing Turing Machines but seemingly there is no need to fuzzy time. Throughout this article, we try to change this picture and show why it is helpful to consider (...) the instants of time as Fuzzy numbers. In physics, though there are revolutionary ideas on the time concept like B theories in contrast to A theory also about central concepts like space, momentum… it is a long time that these concepts are changed, but time is considered classically in all well-known and established physics theories. Seemingly, we stick to the classical time concept in all fields of science and we have a vast inertia to change it. Our goal in this article is to provide some bases why it is rational and reasonable to change and modify this picture. Here, the central point is the modified version of “Unexpected Hanging” paradox as it is described in "Is classical Mathematics appropriate for theory of Computation".This modified version leads us to a contradiction and based on that it is presented there why some problems in Theory of Computation are not solved yet. To resolve the difficulties arising there, we have two choices. Either “choosing” a new type of Logic like “Para-consistent Logic” to tolerate contradiction or changing and improving the time concept and consequently to modify the “Turing Computational Model”. Throughout this paper, we select the second way for benefiting from saving some aspects of Classical Logic. In chapter 2, by applying quantum Mechanics and Schrodinger equation we compute the associated fuzzy number to time. These, provides a new interpretation of Quantum Mechanics.More exactly what we see here is "Particle-Fuzzy time" interpretation of quantum Mechanics, in contrast to some other interpretations of Quantum Mechanics like " Wave-Particle" interpretation. At the end, we propound a question about the possible solution of a paradox in Physics, the contradiction between General Relativity and Quantum Mechanics. (shrink)

In this contribution, I explore the possibility of characterizing the emergence of time in causal set theory (CST) in terms of the growing block universe (GBU) metaphysics. I show that although GBU seems to be the most intuitive time metaphysics for CST, it leaves us with a number of interpretation problems, independently of which dynamics we choose to favor for the theory —here I shall consider the Classical Sequential Growth and the Covariant model. Discrete general covariance of the CSG dynamics (...) does not allow us to individuate a single history of the universe (defined by a causal history of different causal sets), thereby making the claim that ‘the past exists’ at best problematic. In addition, because the evolution of the universe in CSG dynamics leads to an outward branching causal tree, it becomes impossible to determine a proper ‘line of becoming’, thereby blurring the presentists’ claim that only the present exists. Similarly, the covariant approach runs into the same, if not even more severe problems, since each configuration of the universe would amount to a set of possible causal sets, thereby making the individuation of a single configuration of the universe —and thus the physical interpretation of the theory— implausible. (shrink)

In this chapter, we see one way that time flow may force us to develop our physical theory if we add it back into physics proper. Now of course this is speculative in this context, and should be thought of as a model. The two following extracts are from introductions a more complete unified theory. They explain the basic mathematical models that are required to illustrate the point that such models may be plausible. The second extract, ‘the parable of the (...) ants’, introduces us to the ideological-philosophical conflict that prevents such a development being considered in the present generation, which we will go on to next. (shrink)

This is a chapter of the planned monograph "Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity", co-authored by Nick Huggett and Christian Wüthrich and under contract with Oxford University Press. (More information at www<dot>beyondspacetime<dot>net.) This chapter investigates the meaning and significance of string theoretic dualities, arguing they reveal a surprising physical indeterminateness to spacetime.

Special relativity has changed the fundamental view on space and time since Einstein introduced it in 1905. It substitutes four dimensional spacetime for the absolute space and time of Newtonian mechanics. It is believed that the validities of Lorentz invariants are fully confirmed empirically for the last one hundred years and therefore its status are canonical underlying all physical principles. However, spacetime metric is a geometric approach on nature when we interpret the natural phenomenon. A geometric flaw on this will (...) be exhibited and the alternative is suggested. The reasonable geometric model of space and time is a three dimensional space which is translating along the time direction. This model legitimately represents the true characteristic of nature. (shrink)

A number of general theories of physics provide a model for the fundamental rules that govern our universe, becoming a structural framework to which the new discoveries must conform. The theory of relativity is such a general theory. The theory of relativity is a complex theoretical framework that facilitates the understanding of the universal laws of physics. It is based on the curved space-time continuum fabric abstract concept, and it is well suited for interpreting cosmic events. More so, a general (...) theory based on abstract concepts and imagination facilitates the emergence of countless new extravagant theories. A new simplified theory of the natural world is necessary, a simple theory that provides a verifiable framework on which new discoveries can be integrated. The paper describes a view of the abstract time/space concept, and also a very simple model of our ever-changing universe. Views of physicists, mathematicians, chemists, engineers and of course philosophers have to be all in harmony with such a theory. We leave in a beautiful, uniform, and logical world. We live in a world where everything probable is possible. Contact email: [email protected] . (shrink)

The Simulation Hypothesis proposes that all of reality is in fact an artificial simulation, analogous to a computer simulation. Outlined here is a method for programming relativistic mass, space and time at the Planck level as applicable for use in Planck Universe-as-a-Simulation Hypothesis. For the virtual universe the model uses a 4-axis hyper-sphere that expands in incremental steps (the simulation clock-rate). Virtual particles that oscillate between an electric wave-state and a mass point-state are mapped within this hyper-sphere, the oscillation driven (...) by this expansion. Particles are assigned an N-S axis which determines the direction in which they are pulled along by the expansion, thus an independent particle motion may be dispensed with. Only in the mass point-state do particles have fixed hyper-sphere co-ordinates. The rate of expansion translates to the speed of light and so in terms of the hyper-sphere co-ordinates all particles (and objects) travel at the speed of light, time (as the clock-rate) and velocity (as the rate of expansion) are therefore constant, however photons, as the means of information exchange, are restricted to lateral movement across the hyper-sphere thus giving the appearance of a 3-D space. Lorentz formulas are used to translate between this 3-D space and the hyper-sphere co-ordinates, relativity resembling the mathematics of perspective. (shrink)

Following the 26th General Conference on Weights and Measures are fixed the numerical values of the 4 physical constants ($h, c, e, k_B$). This is premised on the independence of these constants. This article discusses a model of a mathematical electron from which can be defined the Planck units as geometrical objects (mass M=1, time T=2$\pi$ ...). In this model these objects are interrelated via this electron geometry such that once we have assigned values to 2 Planck units then we (...) have fixed the values for all Planck units. As all constants can then be defined using geometrical forms (in terms of 2 fixed mathematical constants, 2 unit-specific scalars and a defined relationship between the units $kg, m, s, A$), the least precise CODATA 2014 constants ($G, h, e, m_e, k_B$...) can then be solved via the most precise ($c, \mu_0, \alpha, R_\infty$), with numerical precision limited by the precision of the fine structure constant $\alpha$. In terms of this model we now for example have 2 separate values for elementary charge, calculated from ($c, \alpha, R_\infty$) and the 2017 revision. (shrink)

Outlined here is a simulation hypothesis approach that uses an expanding (the simulation clock-rate measured in units of Planck time) 4-axis hyper-sphere and mathematical particles that oscillate between an electric wave-state and a mass (unit of Planck mass per unit of Planck time) point-state. Particles are assigned a spin axis which determines the direction in which they are pulled by this (hyper-sphere pilot wave) expansion, thus all particles travel at, and only at, the velocity of expansion (the origin of $c$), (...) however only the particle point-state has definable co-ordinates within the hyper-sphere. Photons are the mechanism of information exchange, as they lack a mass state they can only travel laterally (in hypersphere co-ordinate terms) between particles and so this hypersphere expansion cannot be directly observed, relativity then becomes the mathematics of perspective translating between the absolute (hypersphere) and the relative motion (3D space) co-ordinate systems. A discrete `pixel' lattice geometry is assigned as the gravitational space. Units of $\hbar c$ `physically' link particles into orbital pairs. As these are direct particle to particle links, a gravitational force between macro objects is not required, the gravitational orbit as the sum of these individual orbiting pairs. A 14.6 billion year old hyper-sphere (the sum of Planck black-hole units) has similar parameters to the cosmic microwave background. The Casimir force is a measure of the background radiation density. (shrink)

The purpose of this yet-another version of this note is to make another attempt to show how an 'AB-series' interpretation of time, given in a companion paper, leads, surprisingly, apparently, to the signature of the physicists' important AdS^5 geometry. This is not a theory of 2 time dimensions. Rather, it is a theory of 1 time dimension that has both A-series and B-series characteristics.

Usually, the "laboratory" of gravitational tests was the celestial bodies, the astrophysical systems. But such tests are disturbed by non-gravitational effects. The most used such "laboratory" was the solar system. Recently, scientists have focused on observing binary pulsars for the verification of gravitational theories, by observing the variations of the orbital period, thus providing indirect evidence for the emission of gravitational radiation. But the experimenter cannot "arrange the lab" according to his needs, nor trigger certain events when he needs them. (...) But the current technological development is beginning to allow pure laboratory experiments. DOI: 10.13140/RG.2.2.21684.60801 . (shrink)

The classic example of a successful research program is Newton's gravitational theory, probably the most successful Lakatosian research program. Initially, Newton's gravitational theory faced a lot of "anomalies" ("counterexamples") and contradicted the observational theories that supported these anomalies. But supporters of the Newtonian gravity research program have turned every anomaly into corroborating cases. Moreover, they themselves pointed to counterexamples which they then explained through Newtonian theory . DOI: 10.13140/RG.2.2.32489.85601.

Les singularités gravitationnelles dans la relativité générale sont des emplacements dans l'espace-temps où le champ gravitationnel devient infini. Les courbes scalaires invariantes de l'espace-temps incluent une mesure de la densité de la matière. Certains physiciens et philosophes estiment que, du fait que la densité de la matière tend vers l'infini dans la singularité, les lois de l'espace-temps ne sont plus valables là-bas. Le Big Bang est une singularité gravitationnelle acceptée presque unanimement en astrophysique et en cosmologie, en tant que premier (...) état de l'univers. DOI: 10.13140/RG.2.2.32661.06886. (shrink)

This essay invites the reader to interpret physics from a radically empirical standpoint, both diachronic and relative. We start with some criteria of the theory of knowledge, the basis for interpreting the fundamentals of mathematics and physics. -/- Then we present some expositions of physics, including a new characterization of time, space and movement, with reference to classical mechanics, relativity and quantum mechanics.

Four initial postulates are presented (with two more added later), which state that construction of the physical universe proceeds from a sequence of discrete steps or "projections" --- a process that yields a sequence of discrete levels (labeled 0, 1, 2, 3, 4). At or above level 2 the model yields a (3+1)-dimensional structure, which is interpreted as ordinary space and time. As a result, time does not exist below level 2 of the system, and thus the quantum of action, (...) h, which depends on time (since its unit is time•energy), also does not exist below level 2. This implies that the quantum of action is not fundamental, and thus e.g. that the physical universe cannot have originated from a quantum fluctuation. When the gravitational interaction for the model is developed, it is seen that the basic ingredient for gravity is already operating at level 1 of the system, which implies that gravity, too, is not fundamentally quantum mechanical (since, as stated, h only kicks in at level 2) --- perhaps obviating the need for a quantum theory of gravity. Further arguments along this line lead to the conclusion that quantum fluctuations cannot be a source of gravity, and thus cannot contribute to the cosmological constant --- thereby averting the cosmological constant problem. Along the way, the model also provides explanations for dark energy, the beginning and ending of inflation, quark confinement, and more. Although the model dethrones the quantum, it nevertheless elevates an idea in physics that was engendered by quantum mechanics: the necessary role of "observers" in constructing the world. (shrink)

This is a chapter of the planned monograph "Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity", co-authored by Nick Huggett and Christian Wüthrich and under contract with Oxford University Press. (More information at www<dot>beyondspacetime<dot>net.) This chapter introduces causal set theory and identifies and articulates a 'problem of space' in this theory.

This paper introduces some basic ideas and formalism of physics in non-commutative geometry. My goals are three-fold: first to introduce the basic formal and conceptual ideas of non-commutative geometry, and second to raise and address some philosophical questions about it. Third, more generally to illuminate the point that deriving spacetime from a more fundamental theory requires discovering new modes of `physically salient' derivation.

The remarkable connections between gravity and thermodynamics seem to imply that gravity is not fundamental but emergent, and in particular, as Verlinde suggested, gravity is probably an entropic force. In this paper, we will argue that the idea of gravity as an entropic force is debatable. It is shown that there is no convincing analogy between gravity and entropic force in Verlinde’s example. Neither holographic screen nor test particle satisfies all requirements for the existence of entropic force in a thermodynamics (...) system. As a result, there is no entropic force in the gravity system. Furthermore, we show that the entropy increase of the screen is not caused by its statistical tendency to increase entropy as required by the existence of entropic force, but in fact caused by gravity. Therefore, Verlinde’s argument for the entropic origin of gravity is problematic. In addition, we argue that the existence of a minimum size of spacetime, together with the Heisenberg uncertainty principle in quantum theory, may imply the fundamental existence of gravity as a geometric property of spacetime. This provides a further support for the conclusion that gravity is not an entropic force. (shrink)

In this paper, I explore the feasibility of a realistic interpretation of the quantum mechanical path integral - that is, an interpretation according to which the particle actually follows the paths that contribute to the integral. I argue that an interpretation of this sort requires spacetime to have a branching structure similar to the structures of the branching spacetimes proposed by previous authors. I point out one possible way to construct branching spacetimes of the required sort, and I ask whether (...) the resulting interpretation of quantum mechanics is empirically testable. (shrink)

In recent years, the branching spacetime (BST) interpretation of quantum mechanics has come under study by a number of philosophers, physicists and mathematicians. This paper points out some implications of the BST interpretation for two areas of quantum physics: (1) quantum gravity, and (2) stochastic interpretations of quantum mechanics.

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The hole argument concludes that substantivalism about spacetime entails the radical indeterminism of the general theory of relativity (GR). In this paper, I amend and defend a response to the hole argument first proposed by Butterfield (1989) that relies on the idea of counterpart substantivalism. My amendment clarifies and develops the metaphysical presuppositions of counterpart substantivalism and its relation to various definitions of determinism. My defence consists of two claims. First, contra Weatherall (2018) and others: the hole argument is not (...) a blunder resulting from a mistaken view on how mathematical physics works, and requires a developed (meta)metaphysical response. Second, contra Melia (1999) and others: one can be content with a notion of determinism for GR which is not sensitive to merely haecceitistic differences. (shrink)

There is a vast amount of research data accumulating from space exploration on the topics of impacts, symmetries, habitable zone, chemical compositions, atmosphere, climate and geology. The related facts, sayings and relations need to be evaluated by a theory of decision based on strategies of reflection on empirical research and cooperation. More and more suitable technological applications, appropriate inventions and innovations are being introduced for the implementation of the objective to find interstellar habitat. A logic of space science and technology (...) is being, therefore, continuously articulated and innovated through focusing on efficiency, computability, polyvalence, feedback control etc. This effort needs also to be assisted by a reevaluation of conceptual and mathematical frameworks, with the adoption of new physical definitions and new units of measurement. Otherwise, the whole effort remains impeded by its own entitlement. An example of the requirement for conceptual reevaluation is the increasing significance of astrobiology, on account of the quest for water, life and habitable planets. Hereby philosophy of physics meets the philosophy of biology, so far as the concepts of life and non-life could plausibly be reconsidered by space exploration, while ethical problems on the value of space medicine, health and information arise, as well. An example of the urgent requirement for reflection and reevaluation of mathematical frameworks is the task for an efficient motion of spacecraft to the interstellar medium, to Proxima Centauri b and other exoplanets. Such a task should require the adoption of new units of measurement, for instance, of the magnitude of ~6.000 km/s (30 times faster than the Parker Solar Probe), being thus better comparable to the speed of light (since ~6.000 km/s equals to 1/50 or 2% of the speed of light). However, the most significant instant of the challenge to reflection is the role of the magnetosphere, the magnetic fields and dynamos for the development and the motion of the planets of our solar system and exoplanets. A successful procedure to explaining the contribution of the magnetic field to planetary dynamics may help us answer serious scientific questions and probably may crucially contribute to the discovery of a new unified physical theory of everything. -/- . (shrink)

It is nearly impossible to open a textbook on Newtonian mechanics without encountering the concept of inertial frames: the frames that are privileged by the theory’s dynamics. In this paper, I argue that extant definitions of inertial frames are unsatisfactory. I criticise two common definitions of inertial frames: law-based definitions, according to which inertial frames are simply those in which the laws are true, and structure-based definitions, according to which inertial frames are those that are ‘adapted’ to spatiotemporal structure. I (...) then offer a new, symmetry-based definition of inertial frames. This definition offers a non-conventional way of specifying the dynamically privileged frames. The result clarifies the foundations of Newtonian mechanics and accounts for the empirical success of coordinate-dependent formulations of it. (shrink)

The infamous Hole Argument has led philosophers to develop various versions of substantivalism, of which metric essentialism and sophisticated substantivalism are the most popular. In this journal, Trevor Teitel has recently advanced novel arguments against both positions. However, Teitel does not discuss the position of Jeremy Butterfield, which appeals to Lewisian counterpart theory in order to avoid the Hole Argument. In this note I show that the Lewis-Butterfield view is immune to Teitel’s challenges.

Aristotle argues that time depends on soul to count it, but adds that motion, which makes time what it is, may be independent of soul. The claim that time depends on soul or mind implies that there is at least one measurable property of natural beings that exists because of the mind’s activity. This paper argues that for Aristotle time depends partly on soul, but more importantly on motion, which defines a continuum. This argument offers a robust metaphysics of time. (...) In contrast to modern philosophy of physics, for Aristotle the continuum of motion is prior in being to time, while time is a hybrid of the real continuum of motion and the activity of mind. (shrink)

The problem of time involves an overlap between physics, philosophy, psychology and neuroscience. My talk will discuss the role of time in physics but also emphasize that physics may need to expand to address issues usually regarded as being in the other domains. I will first review the mainstream physics view of time, as it arises in Newtonian theory, relativity theory and quantum theory. I will then discuss the various arrows of time, the most fundamental of which is the passage (...) of time associated with consciousness. I will argue that this goes beyond both relativity theory and quantum theory, so that one needs some new physical paradigm to accommodate it. A new paradigm is required anyway to describe quantum gravity and this may elucidate the nature of both time and consciousness. (shrink)

Ce livre propose une étude détaillée et une défense systématique d’une intuition-clé que nous partageons tous à propos de la nature du temps : celle que le futur est ouvert, tandis que le passé est fixé. Si l’occurrence d’une Troisième Guerre mondiale semble indéterminée, il y a bel et bien eu une Première Guerre mondiale. -/- Dans le présent ouvrage, l’auteur fournit une élucidation cohérente, non métaphorique et métaphysiquement éclairante de l’intuition ; il détermine quel modèle de structure temporelle du (...) monde est le plus approprié pour intégrer l’intuition, et s’attarde sur une version spécifique de la théorie du bloc en croissance (GBT) ; enfin, il offre une base naturaliste à GBT, en exploitant les résultats récents des meilleures théories physiques. Trois défis principaux sont ainsi abordés : la réduction des asymétries temporelles à des phénomènes non fondamentaux (par exemple des phénomènes thermodynamiques ou causaux), l’objection épistémique contre GBT ainsi que la tension apparente entre GBT et la physique relativiste. L’auteur conclut que l’asymétrie entre le futur ouvert et le passé fixé doit être ancrée dans la structure temporelle du monde, et que cela n’est ni exclu par notre dispositif épistémique, ni par certaines approches émergentes de la gravité quantique. (shrink)

Shifts are a well-known feature of the literature on spacetime symmetries. Recently, discussions have focused on so-called dynamic shifts, which by analogy with static and kinematic shifts enact arbitrary linear accelerations of all matter (as well as a change in the gravitational potential). But in mathematical formulations of these shifts, the analogy breaks down: while static and kinematic shift act on the matter field, the dynamic shift acts on spacetime structure instead. I formulate a different, `active' version of the dynamic (...) shift which does act on matter. (shrink)

I will present two examples of influential (and incorrect) interpretations of Poincaré, pinpointing their errors and documenting some of their diffusion. The first example, which appears to have been initiated by Moritz Schlick, is the widespread misinterpretation of Poincaré’s argument for geometric conventionalism by basing it on the underdetermination of theories in science. The second example, having to do with Poincaré’s claim that Euclidean and non-Euclidean geometries are inter-translatable, stems from Louis Rougier and was spread in the English language literature (...) by Max Black. I will then reflect on whether it is possible to avoid fragmentation in the interpretation of Poincaré, using Jeremy Gray’s admirable attempt at completeness in his intellectual biography of Poincaré as an example. Finally, I will propose one possible new direction for study of Poincaré that might enrich our view of him substantially by achieving a level of detail that has so far been lacking. (shrink)

It seems natural to ask why the universe exists at all. Modern physics suggests that the universe can exist all by itself as a self-contained system, without anything external to create or sustain it. But there might not be an absolute answer to why it exists. I argue that any attempt to account for the existence of something rather than nothing must ultimately bottom out in a set of brute facts; the universe simply is, without ultimate cause or explanation.

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

The possibility of multi-location—of one entity having more than one exact location—is required by several metaphysical theories such as the immanentist theory of universals and three-dimensionalism about persistence. One of the most pressing challenges for multi-location theorists is that of making sense of exact location—in that extant definitions of exact location entail a principle called ‘functionality’, according to which nothing can have more than one exact location. Recently in a number of promising papers, Antony Eagle has proposed and defended a (...) definition of exact location in terms of weak location that does not entail functionality. This paper provides the first thorough assessment of Eagle’s proposal. In particular, we argue that it cannot account for the location of immanent universals, the multi-location of mereologically changing three-dimensional objects, the multi-location of mereologically complex objects, and that it makes extended simples impossible. (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 concept of inertial frame of reference in classical physics and special theory of relativity is analysed. It has been shown that this fundamental concept of physics is not clear enough. A definition of inertial frame of reference is proposed which expresses its key inherent property. The definition is operational and powerful. Many other properties of inertial frames follow from the definition, or it makes them plausible. In particular, the definition shows why physical laws obey space and time symmetries and (...) the principle of relativity, it resolves the problem of clock synchronization and the role of light in it, as well as the problem of the geometry of inertial frames. (shrink)

A well known conception of axiomatization has it that an axiomatized theory must be interpreted, or otherwise coordinated with reality, in order to acquire empirical content. An early version of this account is often ascribed to key figures in the logical empiricist movement, and to central figures in the early “formalist” tradition in mathematics as well. In this context, Reichenbach’s “coordinative definitions” are regarded as investing abstract propositions with empirical significance. We argue that over-emphasis on the abstract elements of this (...) approach fails to appreciate a rich tradition of empirical axiomatization in the late nineteenth and early twentieth centuries, evident in particular in the work of Moritz Pasch, Heinrich Hertz, David Hilbert, and Reichenbach himself. We claim that such over-emphasis leads to a misunderstanding of the role of empirical facts in Reichenbach’s approach to the axiomatization of a physical theory, and of the role of Reichenbach’s coordinative definitions in particular. (shrink)

We attempt to describe geometry in terms of informational quantities for the universe considered as a finite ensemble of correlated quantum particles. As the main dynamical principle, we use the conservation of the sum of all kinds of entropies: thermodynamic, quantum and informational. The fundamental constant of speed is interpreted as the information velocity for the world ensemble and also connected with the gravitational potential of the universe on a particle. The two postulates, which are enough to derive the whole (...) theory of Special Relativity, are re-formulated as the principles of information entropy universality and finiteness of information density. (shrink)

Two views on the direction of time can be distinguished—primitivism and non-primitivism. According to the former, time’s direction is an in-built, fundamental property of the physical world. According to the latter, time’s direction is a derivative property of a fundamentally directionless reality. In the literature, non-primitivism has been widely supported since most our fundamental dynamical laws are time-reversal invariant. In this paper, I offer a way out to the primitivist. I argue that we do have good grounds to support a (...) primitive direction of time in the quantum realm. The rationale depends on exploiting the metaphysical and dynamical underdetermination of quantum theories to make a case in favor of primitivism. In particular, primitivism can be grounded in spontaneous collapse theories. The specific sense in which these theories capture a primitive direction of time is that, when the ontology of the theory is seriously taken into account, it does not remain invariant under time reversal. In taking GRW with a matter-density field, I will argue that primitivism about the direction of time can be defended in the quantum case. (shrink)

The goal of this essay is twofold. First, it provides a quick look at the foundations of modern relational mechanics by tracing its development from Julian Barbour and Bruno Bertotti's original ideas until present-day's pure shape dynamics. Secondly, it discusses the most appropriate metaphysics for pure shape dynamics, showing that relationalism is more of a nuanced thesis rather than an elusive one. The chapter ends with a brief assessment of the prospects of pure shape dynamics in light of quantum physics.

We present a new metaphysical framework for physics that is conceptually clear, ontologically parsimonious, and empirically adequate. This framework relies on the notion of self-subsisting structure, that is, a set of fundamental physical elements whose individuation and behavior are described in purely relational terms, without any need for a background spacetime. Although the specification of the fundamental elements of the ontology depends on the particular physical domain considered---and is thus susceptible to scientific progress---, the empirically successful structural features of the (...) framework are preserved through theory change. The kinematics and dynamics of these self-subsisting structures are technically implemented using the theoretical framework of Pure Shape Dynamics, which provides a completely relational physical description of a system in terms of the intrinsic geometry of a suitably defined space called shape space. (shrink)

In a first approach, “caring” can be understood as a way of articulating time in full agreement with the need of others. Therefore, and thanks to care, we profit with the access to a peculiar consciousness of time which transcends the practical time of caring and simultaneously fosters and frames our own perception of time itself. Nevertheless, we know that in several care institutions there is a kind of “economic time” which is necessary both to the meeting with the most (...) urgent needs as to fill the scarcity of the available resources. The time of institutionalized care is, above all, measured by the spatial conditions and possibilities as well as by the individuals who daily dwell and struggle in between such factors. The institutionalization of care practices tends to arouse an apparent primacy of space over time. Hospitals, nursing homes, day-care centers for children, recovery centers, among others, are now more likely than ever to fill the lack of time of individuals. Therefore, space is also a material reaction both to the lack of time and to the consciousness of time, especially boosted by those who abandon their loved ones. Based on these multiple articulations of time and space, I will try to show how the relational nature of care is transformed and gives rise to new ways of conceiving the idea of caring. (shrink)

According to the algebraic approach to spacetime, a thoroughgoing dynamicism, physical fields exist without an underlying manifold. This view is usually implemented by postulating an algebraic structure (e.g., commutative ring) of scalar-valued functions, which can be interpreted as representing a scalar field, and deriving other structures from it. In this work, we point out that this leads to the unjustified primacy of an undetermined scalar field. Instead, we propose to consider algebraic structures in which all (and only) physical fields are (...) primitive. We explain how the theory of natural operations in differential geometry—the modern formalism behind classifying diffeomorphism-invariant constructions—can be used to obtain concrete implementations of this idea for any given collection of fields. For concrete examples, we illustrate how our approach applies to a number of particular physical fields, including electrodynamics coupled to a Weyl spinor. (shrink)

Philosophers sometimes wonder whether academic work can ever be truly interdisciplinary. Whether true interdisciplinarity is possible is an open question, but given current trends in higher education, it seems that at least gesturing toward such work is increasingly important. This volume serves as a testament to the fact that such work can be done. Of course, while it is the case that high-level theoretical work can flourish at the intersection of dance and philosophy, it remains to be seen how we (...) might share this with undergraduate students. For many of us in philosophy and dance, a large number of the students we teach are neither philosophy nor dance majors. As such, we are familiar with the challenge of convincing our students to care about our fields. Both philosophy and dance, qua disciplines on a college campus, face similar challenges. These disciplines are often deeply misunderstood, frequently presumed to be “impractical” (a powerful, but confused objection), intimidating, and frivolous. In this chapter, we offer an account of the course we co-taught at Southern Utah University in the Spring of 2016 titled “Movement and Space” as a rough framework for how to introduce the intersection between philosophy and dance to students. We simultaneously attempted to break students of their misconceptions about philosophy and dance, and worked to engage students and professors alike in a truly interdisciplinary educational experience. Treating philosophy as an embodied endeavor, and employing philosophical concepts through the act of dance encouraged students and faculty alike to rethink the fundamental nature of aesthetics. (shrink)

I critically examine the assumption that the theoretical structure that varies under theoretical symmetries is redundant and should be eliminated from a metaphysical picture of the universe, following a ‘symmetry to reality’ inference. I do so by analysing the status of coordinate change symmetries taking a pragmatic approach. I argue that coordinate systems function as indexical devices, and play an important pragmatic role for representing concrete physical systems. I examine the implications of considering this pragmatic role seriously, taking what I (...) call a perspectivist stance. My conclusion is that under a perspectivist stance, all symmetries (including local gauge symmetries) potentially have a direct empirical status: they point to dynamical aspects that are invariant under changes of operationalisation, and they constitute a guide not to reality, but to nomology and kinship. (shrink)

Newton's Principia begins with eight formal definitions and a scholium, the so-called scholium on space and time. Despite a history of misinterpretation, scholars now largely agree that the purpose of the scholium is to establish and defend the de fi nitions of key concepts. There is no consensus, however, on how those definitions differ in kind from the Principia's formal definitions and why they are set-off in a scholium. The purpose of the present essay is to shed light on the (...) scholium by focusing on Newton's notion and use of de fi nition. The resulting view is developmental. I argue that when Newton first wrote the Principia, he viewed the scholium's definitions as items of “natural philosophy.” By the time of the third edition, however, he came to view their methodological status differently; he viewed them as belonging to the more qualified “manner of geometers.” I explicate the two methods of natural inquiry and draw out their implications for Newton's account of space. (shrink)