The aim of this doctoral dissertation is to closely explore the nature of Einstein’s block universe and to tease out its implications for the nature of time and human freedom. Four questions, in particular, are central to this dissertation, and set out the four dimensions of this philosophical investigation: (1) Does the block universe view of time follow inevitably from the theory of special relativity? (2) Is there room for the passage of time in the block universe? (3) Can we (...) distinguish past from future in the block universe? (4) Is there room for human freedom in the block universe? Although the answer of most philosophers would be yes, triple no, my own answer, controversially, is no, triple yes. -/- I thereby challenge the status quo with respect to each of these metaphysical questions, and argue that none of these questions can be answered from looking at physics alone. Physics may constrain our metaphysics, but it certainly does not settle it. What is needed in order to answer these questions, are additional metaphysical assumptions that fall outside the scope of modern physics. My primary goal in this dissertation, therefore, is not to settle the debates on the nature of time and human freedom, but to clarify them by expliciting the metaphysical assumptions that are otherwise left implicit. (shrink)

La relativité générale permet les singularités et nous devons comprendre l'ontologie si nous voulons comprendre la nature de l'espace et du temps dans l'univers d'aujourd'hui. Bien que certains physiciens pensent que les singularités indiquent un échec de la relativité générale, d'autres pensent que les singularités ouvrent un nouvel horizon dans la cosmologie, avec de réels phénomènes physiques pouvant contribuer à un progrès profond dans notre compréhension du monde. DOI: 10.13140/RG.2.2.24491.18728 .

General relativity allows singularities, and we need to understand the ontology of singularities if we want to understand the nature of space and time in the present universe. Although some physicists believe that singularities indicate a failure of general relativity, others believe that singularities open a new horizon in cosmology, with real physical phenomena that can help deepen our understanding of the world. From the definitions of singularities, most known are the possibility that some spacetimes contain incomplete paths (most accepted), (...) the missing points, and the pathology of curvature. DOI: 10.13140/RG.2.2.31611.46888. (shrink)

Relativitatea generală a generat diverse interpretări filosofice timpurii. Adepții lui au evidențiat "relativizarea inerției" și conceptul de simultaneitate, kantienii și neo-kantienii au subliniat abordarea anumitor "forme intelectuale" sintetice (în special principiul covarianței generale, iar empiriștii logici au accentuat semnificația filozofică metodologică a teoriei. Reichenbach a abordat relativitatea generală prin prisma tezei "relativității geometriei", încercând o "axiomatizare constructivă" a teoriei relativității pe baza "problemelor elementare de fapt" (Elementaratbestande) cu privire la comportamentul observabil al razelor de lumină, a tijelor și a ceasurilor. (...) DOI: 10.13140/RG.2.2.27826.76486. (shrink)

General Relativity generated various early philosophical interpretations. His adherents have highlighted the "relativization of inertia" and the concept of simultaneity, Kantians and Neo-Kantians have underlined the approach of certain synthetic "intellectual forms" (especially the principle of general covariance, and logical empirics have emphasized the philosophical methodological significance of the theory. Reichenbach approached the GR through the "relativity of geometry" thesis, trying to build a "constructive axiomatization" of relativity based on "elementary matters of fact" (Elementartatbestande) for the observable behavior of light (...) rays, rods and clocks. The mathematician Hermann Weyl attempted a reconstruction of Einstein's theory based on the epistemology of a "pure infinitesimal geometry", an extended geometry with additional terms that formally identified with the potential of the electromagnetic field. DOI: 10.13140/RG.2.2.11641.93281. (shrink)

Singularitățile la care se ajunge în relativitatea generală prin rezolvarea ecuațiilor lui Einstein au fost și încă mai sunt subiectul a numeroase dezbateri științifice: Există sau nu, singularități? Big Bang a fost o singularitate inițială? Dacă singularitățile există, care este ontologia acestora? Este teoria generală a relativității o teorie care și-a arătat limitele în acest caz? În acest eseu argumentez faptul că există singularități, iar teoria generală a relativității, ca de altfel oricare altă teorie științifică din prezent, nu este valabilă (...) în interiorul orizontului evenimentelor. Dar asta nu presupune, așa cum consideră unii oameni de știință, că ea trebuie considerată ca fiind perimată. După o scurtă prezentare a aspectelor specifice din teoria clasică newtoniană și teoria specială a relativității, și o scurtă prezentare a teoriei generale a relativității, în capitolul Ontologia relativității generale prezint aspectele ontologice specifice relativității generale. Următorul capitol, Singularități, este dedicat prezentării singularităților care rezultă în relativitatea generală, a aspectelor specifice ale găurilor negre și orizontul evenimentelor, inclusiv dezbaterea despre Big Bang ca singularitate inițială, și argumentele în favoarea existenței singularităților. În Ontologia singularităților vorbesc despre posibilitățile de încadrare ontologică a singularităților în general și a găurilor negre în special, despre argumentul găurii pus în evidență de Einstein, și argumentele prezentate de oamenii de știință că nu există singularități și deci că teoria generală a relativității este în impas. Închei cu Concluziile în care expun și reiau pe scurt argumentele care ămi susțin opiniile prezentate mai sus. Aceasta este o traducere din limba engleză a lucrării: Sfetcu, Nicolae, "The singularities as ontological limits of the general relativity". (shrink)

The singularities from the general relativity resulting by solving Einstein's equations were and still are the subject of many scientific debates: Are there singularities in spacetime, or not? Big Bang was an initial singularity? If singularities exist, what is their ontology? Is the general theory of relativity a theory that has shown its limits in this case? In this essay I argue that there are singularities, and the general theory of relativity, as any other scientific theory at present, is not (...) valid for singularities. But that does not mean, as some scientists think, that it must be regarded as being obsolete. After a brief presentation of the specific aspects of Newtonian classical theory and the special theory of relativity, and a brief presentation of the general theory of relativity, the chapter Ontology of General Relativity presents the ontological aspects of general relativity. The next chapter, Singularities, is dedicated to the presentation of the singularities resulting in general relativity, the specific aspects of the black holes and the event horizon, including the Big Bang debate as original singularity, and arguments for the existence of the singularities. In Singularity Ontology, I am talking about the possibilities of ontological framing of singularities in general and black holes in particular, about the hole argument highlighted by Einstein, and the arguments presented by scientists that there are no singularities and therefore that the general theory of relativity is in deadlock. In Conclusions I outline and summarize briefly the arguments that support my above views. -/- DOI: 10.58679/TW62329. (shrink)

I argue that the best interpretation of the general theory of relativity has need of a causal entity, and causal structure that is not reducible to light cone structure. I suggest that this causal interpretation of GTR helps defeat a key premise in one of the most popular arguments for causal reductionism, viz., the argument from physics.

Pierre Duhem’s philosophy of science has influenced many philosophers in the twentieth century, and even today. Many of the subjects he addressed are still highly discussed today, especially the distinction between science and metaphysics. My aim in this paper will be to motivate a naturalistic approach where the difference between physics and metaphysics is only a matter of degree. I focus on whether it would be possible to articulate this gradual distinction from a duhemian point of view. Although Duhem thought (...) that metaphysics is an entirely different and more excellent activity than physics, I believe that Duhem’s philosophy of science also supports a naturalistic distinction in terms of degrees. I offer three reasons to justify this conclusion: Duhem’s notion of common sense; Duhem’s holism and his views on the generality of our theories, and Duhem’s notion of natural classification. At the end of the paper I will argue that a naturalistic approach accomplishes must of what Duhem wanted to achieve with his distinction. (shrink)

In light of the Special Theory of Relativity and the Minkowski creation of ‘spacetime’, the universe is taken to be a four-dimensional entity which postulates bodies as existing within a temporally extended reality. The Special Theory of Relativity’s implications liken the nature of the universe to a ‘block’ within which all events coexist equally in spacetime. Such a view strikes against the very essence of presentism, which holds that all that exists is the instantaneous state of objects in the present (...) moment. With respect to the present moment, events have a clear division into the past or future, however such regions do not exist in reality and the universe is a three-dimensional entity. The consequences of a four-dimensional universe are disturbing to say the least for our everyday human experience, with once objective facts about reality becoming dependent upon an observer’s relative motion and the debate over the extent of true free will in a Block Universe. This paper will look at arguments which seek to rescue the presentist view in light of Special Relativity so such four-dimensionalist implications do not have to be accepted. Two approaches will be considered. The first accepts that presentism is incompatible with Special Relativity, and seeks to show that the theory is ultimately false. The second holds that it is the Block Universe interpretation of Special Relativity that is wrong, and a version of presentism can be reconciled with Special Relativity. The paper will expound and critically examine both of these approaches to review whether the case for the three-dimensionalist and a fundamental passage of time can be made. (shrink)

While Einstein considered that sub specie astern the correct philosophical position regarding geometry was that of the conventionality of geometry, he felt that provisionally it was necessary to adopt a non-conventional stance that he called practical geometry. here we will make the case that even when adopting Einstein’s views we must conclude that practical geometry is conventional after all. Einstein missed the fact that the conventionality of simultaneity leads to a conventional element in the chrono-geometry, since it corresponds to the (...) possibility of different space-time metrics. (shrink)

Review of ‘Physical Theory: Method and Interpretation’ edited by Lawrence Sklar.

The paper investigates the status of gravitational energy in Newtonian Gravity, developing upon recent work by Dewar and Weatherall. The latter suggest that gravitational energy is a gauge quantity. This is potentially misleading: its gauge status crucially depends on the spacetime setting one adopts. In line with Møller-Nielsen’s plea for a motivational approach to symmetries, we supplement Dewar and Weatherall’s work by discussing gravitational energy–stress in Newtonian spacetime, Galilean spacetime, Maxwell-Huygens spacetime, and Newton–Cartan Theory. Although we ultimately concur with Dewar (...) and Weatherall that the notion of gravitational energy is problematic in NCT, our analysis goes beyond their work. The absence of an explicit definition of gravitational energy–stress in NCT somewhat detracts from the force of Dewar and Weatherall’s argument. We fill this gap by examining the supposed gauge status of prima facie plausible candidates—NCT analogues of gravitational energy–stress pseudotensors, the Komar mass, and the Bel-Robinson tensor. Our paper further strengthens Dewar and Weatherall’s results. In addition, it sheds more light upon the subtle link between sufficiently rich inertial structure and the definability of gravitational energy in NG. (shrink)

The questions of what represents space-time in GR, the status of gravitational energy, the substantivalist-relationalist issue, and the exceptional status of gravity are interrelated. If space-time has energy-momentum, then space-time is substantival. Two extant ways to avoid the substantivalist conclusion deny that the energy-bearing metric is part of space-time or deny that gravitational energy exists. Feynman linked doubts about gravitational energy to GR-exceptionalism, as do Curiel and Duerr; particle physics egalitarianism encourages realism about gravitational energy. In that spirit, this essay (...) proposes a third possible view about space-time, one involving a particle physics-inspired non-perturbative split that characterizes space-time with a constant background _matrix_, a sort of vacuum value, thus avoiding the inference from gravitational _energy to substantivalism. On this proposal, space-time is, where eta=diag is a spatio-temporally constant numerical signature matrix, a matrix already used in GR with spinors. The gravitational potential, to which any gravitational energy can be ascribed, is g_{\mu\nu}- eta, an _affine_ geometric object with a tensorial Lie derivative and a vanishing covariant derivative. This non-perturbative split permits strong fields, arbitrary coordinates, and arbitrary topology, and hence is pure GR by almost any standard. This razor-thin background, unlike more familiar backgrounds, involves no extra gauge freedom and so lacks their obscurities and carpet lump-moving. After a discussion of Curiel's GR exceptionalist denial of the localizability of gravitational energy and his rejection of energy conservation, the two traditional objections to pseudotensors, coordinate dependence and nonuniqueness, are explored. Both objections are inconclusive and getting weaker. A literal interpretation involving infinitely many energies corresponding by Noether's first theorem to the infinite symmetries of the _action_ largely answers Schroedinger's false-negative coordinate dependence problem. Bauer's false-positive objection has multiple answers. Non-uniqueness might be handled by Nester et al.'s finding physical meaning in multiplicity in relation to boundary conditions, by an optimal candidate, or by Bergmann's identifying the non-uniqueness and coordinate dependence ambiguities as one. (shrink)