McTaggart distinguished two conceptions of time: the A-series, according to which events are either past, present or future; and the B-series, according to which events are merely earlier or later than other events. Elsewhere, I have argued that these two views, ostensibly about the nature of time, need to be reinterpreted as two views about the nature of the universe. According to the so-called A-theory, the universe is three dimensional, with a past and future; according to the B-theory, the universe (...) is four dimensional. Given special relativity (SR), we are obliged, it seems, to accept (a modified version of) the B-series, four dimensional view, and reject the A-series, three dimensional view, because SR denies that there is a privileged, instantaneous cosmic "now" which seems to be required by the A-theory. Whether this is correct or not, it is important to remember that the fundamental problem, here, is not "What does SR imply?", but rather "What is the best guess about the ultimate nature of the universe in the light of current theoretical knowledge in physics?". In order to know how to answer this question, we need to have some inkling as to how the correct theory of quantum gravity incorporates quantum theory, probability and time. This is, at present, an entirely open question. String theory, or M-theory, seems to evade the issue, and other approaches to quantum gravity seem equally evasive. However, if probabilism is a fundamental feature of ultimate physical reality, then it may well be that the A-theory, or rather a closely related doctrine I call “objectism”, is built into the ultimate constitution of things. (shrink)

Physics has often undermined the notion of free will, and philosophers have been concerned about this for many reasons. One is that freedom seems to be a necessary condition for moral responsibility. This chapter explains how special theory of relativity (STR) leads to the idea that there is no flow of time. It analyzes several proposals that reintroduce a classical view of time without violating relativity. The chapter suggests two ways in which the philosophy of science can add some helpful (...) perspective to the debate. It discusses how Einstein took gravity to be a geometric property of space time rather than a force and that general theory of relativity (GTR) conflicts with the Standard Model of particle physics. The chapter explains that there are several possible moves one might make in order to preserve a classical view of time. (shrink)

We introduce an Absolute (Relative) Time-consistent Axiom of Revealed Preference which characterizes the consistency of a choice function with the property of absolute (relative) time-consistency and impatience. The axiom requires that the absolute (relative) time-consistent and impatient closure of the revealed preference relation does not conflict with the strict revealed preference relation.

The development by Locke, Herder, and others of the concept of relative time, each time unit differing qualitatively and intrinsically according to the process of which it forms a part, bears on the nature of historical explanation. There is no universal time; the world "is" as it "appears" for every viewpoint; achievements of different periods, seemingly the same, differ by virtue of their contexts; phenomena are truly individualizable only through appraisal relative to these contexts which make explanation possible; (...) even contemporary generations perceive a moment in different historical times; any of numerous different though equivalent descriptions can logically replace temporal statements. (shrink)

The aim of this book is to give an account of Einstein's work without introducing anything very technical in the way of mathematics, physics, or philosophy.

Physical Relativity explores the nature of the distinction at the heart of Einstein's 1905 formulation of his special theory of relativity: that between kinematics and dynamics. Einstein himself became increasingly uncomfortable with this distinction, and with the limitations of what he called the 'principle theory' approach inspired by the logic of thermodynamics. A handful of physicists and philosophers have over the last century likewise expressed doubts about Einstein's treatment of the relativistic behaviour of rigid bodies and clocks in motion in (...) the kinematical part of his great paper, and suggested that the dynamical understanding of length contraction and time dilation intimated by the immediate precursors of Einstein is more fundamental. Harvey Brown both examines and extends these arguments, after giving a careful analysis of key features of the pre-history of relativity theory. He argues furthermore that the geometrization of the theory by Minkowski in 1908 brought illumination, but not a causal explanation of relativistic effects. Finally, Brown tries to show that the dynamical interpretation of special relativity defended in the book is consistent with the role this theory must play as a limiting case of Einstein's 1915 theory of gravity: the general theory of relativity.Appearing in the centennial year of Einstein's celebrated paper on special relativity, Physical Relativity is an unusual, critical examination of the way Einstein formulated his theory. It also examines in detail certain specific historical and conceptual issues that have long given rise to debate in both special and general relativity theory, such as the conventionality of simultaneity, the principle of general covariance, and the consistency or otherwise of the special theory with quantum mechanics. Harvey Brown' s new interpretation of relativity theory will interest anyone working on these central topics in modern physics. (shrink)

N. Maxwell (1985) has claimed that special relativity and "probabilism" are incompatible; "probabilism" he defines as the doctrine that "the universe is such that, at any instant, there is only one past but many alternative possible futures". Thus defined, the doctrine is evidently prerelativistic as it depends on the notion of a universal instant of the universe. In this note I show, however, that there is a straightforward relativistic generalization, and that therefore Maxwell's conclusion that the special theory of relativity (...) should be amended is unwarranted. I leave open the question whether or not probabilism (or the related doctrine of the flow of time) is true, but argue that the special theory of relativity has no fundamental significance for this question. (shrink)

The larger project of which this volume forms part is an attempt to craft a coherent doctrine of divine eternity and God's relationship to time.

According to a widespread view, Einstein’s definition of time in his special relativity is founded on the positivist verification principle. The present paper challenges this received outlook. It shall be argued that Einstein’s position on the concept of time, to wit, simultaneity, is best understood as a mitigated version of concept empiricism. He contrasts his position to Newton’s absolutist and Kant’s transcendental arguments, and in part sides with Hume’s and Mach’s empiricist arguments. Nevertheless, Einstein worked out a concept empiricism that (...) is considerably more moderate than what we find in the preceding empiricist tradition and early logical positivism. He did not think that the origin of concepts is in observations, but in conventions, and he also maintained a realist ontology of physical events, which he thought is necessary for his theory. Consequently, his philosophy of time in special relativity is not couched in terms of an anti-metaphysical verificationism. (shrink)

This article provides a non-technical overview of the conflict between the special theory of relativity and the dynamic theories of time. The chief argument against dynamic theories of time from relativistic mechanics is presented. The space of current responses to that argument is subsequently mapped.

In the transition to Einstein’s theory of Special Relativity (SR), certain concepts that had previously been thought to be univocal or absolute properties of systems turn out not to be. For instance, mass bifurcates into (i) the relativistically invariant proper mass m0, and (ii) the mass relative to an inertial frame in which it is moving at a speed v = βc, its relative mass m, whose quantity is a factor γ = (1 – β2) -1/2 times (...) the proper mass, m = γm0. (shrink)

This chapter contains sections titled: Coordinate Systems: Euclidean Space Invariant Quantities Classical Space‐times Special Relativity Consequences of the Lorentz Transformation Lorentz Invariant Quantities.

When addressing the notion of proper time in the theory of relativity, it is usually taken for granted that the time read by an accelerated clock is given by the Minkowski proper time. However, there are authors like Harvey Brown that consider necessary an extra assumption to arrive at this result, the so-called clock hypothesis. In opposition to Brown, Richard TW Arthur takes the clock hypothesis to be already implicit in the theory. In this paper I will present a view (...) different from these authors by taking into account Einstein’s notion of natural clock and showing its relevance to the debate. (shrink)

Two radically different views about time are possible. According to the first, the universe is three dimensional. It has a past and a future, but that does not mean it is spread out in time as it is spread out in the three dimensions of space. This view requires that there is an unambiguous, absolute, cosmic-wide "now" at each instant. According to the second view about time, the universe is four dimensional. It is spread out in both space and time (...) - in space-time in short. Special and general relativity rule out the first view. There is, according to relativity theory, no such thing as an unambiguous, absolute cosmic-wide "now" at each instant. However, we have every reason to hold that both special and general relativity are false. Not only does the historical record tell us that physics advances from one false theory to another. Furthermore, elsewhere I have shown that we must interpret physics as having established physicalism - in so far as physics can ever establish anything theoretical. Physicalism, here, is to be interpreted as the thesis that the universe is such that some unified "theory of everything" is true. Granted physicalism, it follows immediately that any physical theory that is about a restricted range of phenomena only, cannot be true, whatever its empirical success may be. It follows that both special and general relativity are false. This does not mean of course that the implication of these two theories that there is no unambiguous cosmic-wide "now" at each instant is false. It still may be the case that the first view of time, indicated at the outset, is false. Are there grounds for holding that an unambiguous cosmic-wide "now" does exist, despite special and general relativity, both of which imply that it does not exist? There are such grounds. Elsewhere I have argued that, in order to solve the quantum wave/particle problem and make sense of the quantum domain we need to interpret quantum theory as a fundamentally probabilistic theory, a theory which specifies how quantum entities - electrons, photons, atoms - interact with one another probabilistically. It is conceivable that this is correct, and the ultimate laws of the universe are probabilistic in character. If so, probabilistic transitions could define unambiguous, absolute cosmic-wide "nows" at each instant. It is entirely unsurprising that special and general relativity have nothing to say about the matter. Both theories are pre-quantum mechanical, classical theories, and general relativity in particular is deterministic. The universe may indeed be three dimensional, with a past and a future, but not spread out in four dimensional space-time, despite the fact that relativity theories appear to rule this out. These considerations, finally, have implications for views about the arrow of time and free will. (shrink)

Is the objective passage of time compatible with relativistic physics? There are two easy routes to an affirmative answer: (1) provide a deflationary analysis of passage compatible with the block universe, or (2) argue that a privileged global present is compatible with relativity. (1) does not take passage seriously. (2) does not take relativity seriously. This paper is concerned with the viability of views that seek to take both passage and relativity seriously. The investigation proceeds by considering how traditional A-theoretic (...) conceptions of passage might be generalized to relativistic space-times without incorporating a privileged global present. I argue that the most promising position marries the idea that open possibilities for the future are settled as time passes with a ‘non-standard’ interpretation of the relevant formal models. (shrink)

The General Theory of Relativity (GR) and the Dynamic Universe (DU) are evaluated in how they explain frequencies of atomic clocks. DU and GR predict the frequencies with equal accuracy, but their explanations, the postulates they apply in the explanations and the word-views that come along with them are entirely different. The central argument is that if unified and under- standable physics is appreciated, then DU deserves to be taken as a viable alternative to GR. In GR different frequencies of (...) identical atomic clocks are explained by letting rates of the flow of time in their frames of reference vary as functions of the clocks’ states of motion and gravitation. The GR- based world-view is nonunderstandable because GR violates absolute simultaneity, and disunified because quantum mechanics is built on different postulates than GR. In DU different frequencies of identical atomic clocks are explained by letting their frequencies vary as functions of their states of motion and gravitation. As DU commits to absolute simultaneity and as the postulates of DU suffice as the ontological ground of quantum mechanics at least partially, DU provides an under- standable and unified scientific world-view. -/- Résumé: La théorie de la relativité générale (RG) et de l’univers dynamique (UD) sont évalués sur la fac ̧on dont ils expliquent les fréquences des horloges atomiques. La RG et l’UD prédisent les fréquences avec une précision égale, mais leurs explications, les postulats qu’ils appliquent aux explications et les visions du monde qui les accompagnent sont entie`rement différents. L’argument central est que si l’on reconnaˆıt la physique unifiée et compréhensible, alors l’UD mérite d’ être considéré comme une alternative viable à la RG. En RG, différentes fréquences d’horloges atomiques identiques sont expliquées en faisant varier les vitesses de l’écoulement du temps dans leurs cadres de référence en fonction des états de mouvement et de la gravitation des horloges. La vue du monde basée sur la RG est incompréhensible parce que la RG viole la simultanéité absolue, et est désunifiée parce que la mécanique quantique est construite sur des postulats différents de ceux de la RG. Dans l’UD, différentes fréquences d’horloges atomiques identiques sont expliquées en laissant leurs fréquences varier en fonction de leurs états de mouvement et de gravitation. Comme l’UD s’engage à la simultanéité absolue et que les postulats de l’UD suffisent, au moins en partie, comme fondements ontologiques de la mécanique quantique, l’UD fournit une vision du monde scientifique compréhensible et unifiée. (shrink)

In this essay I address the issue of whether Einstein's Special Theory of Relativity counts against a tensed or "A-series" understanding of time. Though this debate is an old one, it continues to be lively with many prominent authors recently arguing that a genuine A-series is compatible with a relativistic world view. My aim in what follows is to outline why Special Relativity is thought to count against a tensed understanding of time and then to address the philosophical attempts to (...) reconcile the two theories. I conclude that while modern physics on its own does not rule out the possibility of a real A-series, the combination of Einstein's theory and the philosophical arguments against tense is decisive. The upshot is that the tenseless or "B-series" view of time is the best one. (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)

One of the most significant challenges in the application of brain-computer interfaces is the large performance variation, which often occurs over time or across users. Recent evidence suggests that the physiological states may explain this performance variation in BCI, however, the underlying neurophysiological mechanism is unclear. In this study, we conducted a seven-session motor-imagery experiment on 20 healthy subjects to investigate the neurophysiological mechanism on the performance variation. The classification accuracy was calculated offline by common spatial pattern and support vector (...) machine algorithms to measure the MI performance of each subject and session. Relative Power values from different rhythms and task stages were used to reflect the physiological states and their correlation with the BCI performance was investigated. Results showed that the alpha band RP from the supplementary motor area within a few seconds before MI was positively correlated with performance. Besides, the changes of RP between task and pre-task stage from theta, alpha, and gamma band were also found to be correlated with performance both across time and subjects. These findings reveal a neurophysiological manifestation of the performance variations, and would further provide a way to improve the BCI performance. (shrink)

The concept of a time-relative interest is introduced by Jeff McMahan to solve certain puzzles about the badness of death. Some people (e.g. McMahan and David DeGrazia) believe that this concept can also be used to show that abortion is permissible. In this paper, I first argue that if the Time-Relative Interest Account permits abortion, then it would also permit infanticide.

This paper argues that idealism can offer a new solution to the problem of relating the “static” presence of things to eternity and the “dynamic” passage of reality in the temporal realm. I first offer a presentation of this problem using the dispute between Aquinas and Scotus, then describe “ontological idealism about time,” as a smaller–scale idealism, and show how it resolves the original problem. I conclude by demonstrating that this view is consonant with the recent emphasis on the ontological (...) dependence of things on God and that it offers a way of bringing together non–eternalist ontologies and the ontological conclusions posited by the special theory of relativity. (shrink)

The need for a time-shift invariant formulation of quantum theory arises from fundamental symmetry principles as well as heuristic cosmological considerations. Such a description then leaves open the question of how to reconcile global invariance with the perception of change, locally. By introducing relative time observables, we are able to make rigorous the Page–Wootters conditional probability formalism to show how local Heisenberg evolution is compatible with global invariance.

B- theorists frequently argue that the A- theoretic views are incompatible with the Special Theory of Relativity (STR) and that this is a problem for the A- theoretic views. however, the B- theory needs to be revised in light of implications of STR. in particular, it follows from STR that some events stand in genuine temporal relations to each other while others do not. Consequently, there isn’t a single temporal order of all events. instead, there are multiple B- series. Some (...) B- theorists defend a view of the passage of time according to which passage is simply temporal succession. This paper argues that, in Minkowski spacetime, time passes in each of the multiple B- series, but there is no passage spanning across all events because some events stand in no genuine temporal relations to each other. (shrink)

In this paper I try to sort out a tangle of issues regarding time, inertia, proper time and the so-called “clock hypothesis” raised by Harvey Brown's discussion of them in his recent book, Physical Relativity. I attempt to clarify the connection between time and inertia, as well as the deficiencies in Newton's “derivation” of Corollary 5, by giving a group theoretic treatment original with J.-P. Provost. This shows how both the Galilei and Lorentz transformations may be derived from the relativity (...) principle on the basis of certain elementary assumptions regarding time. I then reflect on the implications of this derivation for understanding proper time and the clock hypothesis. (shrink)

In this thesis the author focuses on the metaphysical implications of the realist interpretation of special relativity. The realist interpretation is found wanting in coherence as it utilizes metaphysical concepts (as causation) that are left unjustified if the theory is taken at face value. The author points at a possible re-interpretation of special relativity that allows for a coherent metaphysical basis while containing the mathematical structure of the theory.

Don Marquis has argued most abortions are immoral, for the same reason that killing you or me is immoral: abortion deprives the fetus of a valuable future. Call this account the FLOA. A rival account is Jeff McMahan’s, time-relative interest account of the wrongness of killing. According to this account, an act of killing is wrong to the extent that it deprives the victim of future value and the relation of psychological unity would have held between the victim at (...) the time of death and herself at a later time if she had lived. The TRIA supposedly has two chief advantages over Marquis’s FLOA. First, unlike the FLOA, the TRIA does not rely on the controversial thesis that identity is what matters in survival. Second, the TRIA yields more plausible verdicts about cases. Proponents of the TRIA use the account to argue that abortion is generally permissible, because there would be little to no psychological unity between the fetus and later selves if it lived. I argue that advocates of the TRIA have failed to establish its superiority to the FLOA, for two reasons. First, the two views are on a par with respect to the thesis that identity is what matters in survival. Second, Marquis’s FLOA does not yield the counterintuitive implications about cases that advocates of the TRIA have attributed to it, and the TRIA yields its own share of implausible judgments about cases. (shrink)

Sellars once wrote that “‘the problem of time’ is rivaled only by the ‘mind-body problem’ in the extent to which it inexorably brings into play all the major concerns of philosophy”. Considering that time plays a major role both in our inner life and in the description of the outer world, one could suggest that two problems are deeply related: our progress in understanding bits of the problem of time might shed light into the mind-body problem and vice versa. In (...) this paper, I will test the plausibility of this suggestion, by focusing on a fundamental aspect of the relationship between the ‘time of physics’ and the ‘time of mind’, namely the problem of their compatibility. (shrink)

This book is a treatise on time and on background independence in physics. It first considers how time is conceived of in each accepted paradigm of physics: Newtonian, special relativity, quantum mechanics (QM) and general relativity (GR). Substantial differences are moreover uncovered between what is meant by time in QM and in GR. These differences jointly source the Problem of Time: Nine interlinked facets which arise upon attempting concurrent treatment of the QM and GR paradigms, as is required in particular (...) for a background independent theory of quantum gravity. A sizeable proportion of current quantum gravity programs - e.g. geometrodynamical and loop quantum gravity approaches to quantum GR, quantum cosmology, supergravity and M-theory - are background independent in this sense. This book's foundational topic is thus furthermore of practical relevance in the ongoing development of quantum gravity programs. This book shows moreover that eight of the nine facets of the Problem of Time already occur upon entertaining background independence in classical (rather than quantum) physics. By this development, and interpreting shape theory as modelling background independence, this book further establishes background independence as a field of study. Background independent mechanics, as well as minisuperspace (spatially homogeneous) models of GR and perturbations thereabout are used to illustrate these points. As hitherto formulated, the different facets of the Problem of Time greatly interfere with each others' attempted resolutions. This book explains how, none the less, a local resolution of the Problem of Time can be arrived at after various reconceptualizations of the facets and reformulations of their mathematical implementation. Self-contained appendices on mathematical methods for basic and foundational quantum gravity are included. Finally, this book outlines how supergravity is refreshingly different from GR as a realization of background independence, and what background independence entails at the topological level and beyond. (shrink)

It has been shown that the Lorentz transformations in special relativity can be derived in terms of the principle of relativity and certain properties of space and time such as homogeneity. In this paper, we argue that the free Schrodinger equation in quantum mechanics may also be regarded as a consequence of the homogeneity of space and time and the principle of relativity when assuming linearity of time evolution.

In the first part of this contribution, we review the development of the theory of scale relativity and its geometric framework constructed in terms of a fractal and nondifferentiable continuous space-time. This theory leads (i) to a generalization of possible physically relevant fractal laws, written as partial differential equation acting in the space of scales, and (ii) to a new geometric foundation of quantum mechanics and gauge field theories and their possible generalisations. In the second part, we discuss some examples (...) of application of the theory to various sciences, in particular in cases when the theoretical predictions have been validated by new or updated observational and experimental data. This includes predictions in physics and cosmology (value of the QCD coupling and of the cosmological constant), to astrophysics and gravitational structure formation (distances of extrasolar planets to their stars, of Kuiper belt objects, value of solar and solar-like star cycles), to sciences of life (log-periodic law for species punctuated evolution, human development and society evolution), to Earth sciences (log-periodic deceleration of the rate of California earthquakes and of Sichuan earthquake replicas, critical law for the arctic sea ice extent) and tentative applications to systems biology. (shrink)

A child’s age in comparison to the age of her or his classmates (relative age) has been found to be an influential factor on academic achievement, particularly but not exclusively at the beginning of formal schooling. However, few studies have focused on the generalizability of relative age effects. To close this gap, the present study analyzes the generalizability across students with and without immigrant backgrounds, across three student cohorts that entered school under a changing law of school enrollment, (...) and across classes. To this end, we capitalized on representative large-scale data sets from three student cohorts attending public schools in Berlin, the capital of Germany. We analyzed the data using a multilevel framework. Our results for the overall student sample indicate relative age effects for reading and mathematics in favor of the relatively older students in Grade 2 that become somewhat smaller in size in Grade 3. By Grade 8, relative age effects had vanished in reading and had even reversed in favor of the relatively young in mathematics. Furthermore, relative age effects were not found to be systematically different among students with and without immigrant backgrounds, student cohorts, or across classes. Taken together, these results empirically underscore the broad generalizability of the findings as found for the overall student population and replicate the pattern of findings on relative effects as identified by the majority of previous studies. (shrink)

In this paper, I start with the opposition between the Husserlian project of a phenomenology of the experience of time, started in 1905, and the mathematical and physical theory of time as it comes out of Einstein’s special theory of relativity in the same year. Although the contrast between the two approaches is apparent, my aim is to show that the original program of Husserl’s time theory is the constitution of an objective time and a time of the world, starting (...) from the intuitive giveness of time, i.e., from time as it appears. To show this, I stress the structural similarity between Husserl’s original question of time and the problem of a phenomenology of space constitution as it was first developed in the his manuscripts from the nineteenth century, in which we find the threefold question of the origin of our representation of space, of the geometrization of intuitive space, and of the constitution of transcendent world space. Finally, I reconsider some of Husserl’s main theses about the phenomenological constitution of objective time in light of the main results of special relativity time-theory, introducing several corrections to central assumptions that underlie Husserl’s theory of time. (shrink)

In 1905 Albert Einstein, in a paper entitled “On the Electrodynamics of Moving Bodies”, as a solution to the disagreement between classical mechanics and the results of the Michelson's experiment, who showed the invariance of the speed of light in vacuum measured in different inertial reference systems, developed the theory of special relativity. In this essay Einstein expounded a theory that, instead of introducing a privileged system, required the revision of the concepts of space and time of classical physics. Combining (...) the principle of Galilean relativity, according to which the laws of physics are invariant in all inertial reference systems, with the physics of electromagnetism, according to which the speed of light in a vacuum is constant, Einstein concluded that time is no more than a relative measure, namely that whenever we have to do with speed equal to or close to that of light, time is no longer a variable absolute and independent of the reference system adopted, but depends on the variable position. This is what Einstein shows through the critical examination of the concept of simultaneity. The abandonment of the traditional conception of space and time based on the idea of a spatial continuum flowing through a temporal continuum coherently leads to the assumption of a space-time continuum in which distances and time intervals vary with the changing the reference system, and together vary, of course, all other sizes to those connected. (shrink)

Old and recent ideas concerning the nature of time are reviewed, starting from Mach's refusal of Newton's absolute time. Many experiments show that the slowing down of moving clocks is a real phenomenon. Such must then also be the so-called “twin paradox,” which owes its name to its evident incompatibility with the philosophy of relativism (not to be confused with the theory of relativity). The Lorentz reformulation of special relativity started by postulating physical effects of the ether, but accepted Einstein's (...) clock synchronization. Only because of this Lorentz could not understand the advantages of an easily deducible different theory. As stressed by Popper, one of the main problems of the usual approach is the introduction of a superdeterministic universe. Recent results obtained by the author show that a theory is possible, based on relative time but on absolute simultaneity, in which the conceptual difficulties of relativity are avoided. (shrink)

What picture of reality emerges from the attempt to hold together the following three claims? (1) For temporal beings only the present, not the past or the future, exists. (2) For God, all times are present. (3) For temporal beings, what counts as present varies from individual to individual, as described in the theory of relativity. These claims jointly suggest that reality is always reality for—for God, or for this or that creature. This is neither relativism nor anti-metaphysical phenomenology; (...) instead, it looks more like a modest but insistent development of the Thomistic doctrine of participation in being. Being is not a neutral and amorphous glop spread out before just any observer; rather, it belongs to and is measured by particular beings. Created being as a whole belongs to God (and, eventually, to the saints in God), whereas the share in being assigned to any creature is limited. (shrink)

I argue that truth is relative (in the sense recently defended by some prominent analytical philosophers) by focusing on some semantic issues raised by Einstein's theory of relativity together with our ordinary attributions of truth.