10,610 research outputs found

    The singularities as ontological limits of the general relativity

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    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/TW6232

    `Iconoclastic', Categorical Quantum Gravity

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    This is a two-part, `2-in-1' paper. In Part I, the introductory talk at `Glafka--2004: Iconoclastic Approaches to Quantum Gravity' international theoretical physics conference is presented in paper form (without references). In Part II, the more technical talk, originally titled ``Abstract Differential Geometric Excursion to Classical and Quantum Gravity'', is presented in paper form (with citations). The two parts are closely entwined, as Part I makes general motivating remarks for Part II.Comment: 34 pages, in paper form 2 talks given at ``Glafka--2004: Iconoclastic Approaches to Quantum Gravity'' international theoretical physics conference, Athens, Greece (summer 2004

    Freedom Giving Birth to Order: Philosophical Reflections on Peirce's Evolutionary Cosmology and its Contemporary Resurrections

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    This paper seeks to show that Charles Sanders Peirce's interest in an evolutionary account of the laws of nature is motivated both by his desire to extend the scope of the application of the Principle of Sufficient Reason (PSR) and by his attempt to explain the success of our deployment of the PSR, which presupposes the existence of determinate causal structures. One can situate Peirce's concern with the explanation of the laws of nature in relation to the influences of Naturphilosophie on Peirce. I then show that some strands of contemporary physics can be understood as resurrections of Peirce's evolutionary cosmology. I show that we can understand Lee Smolin's theory of "cosmological natural selection" as a version of Peirce's evolutionary cosmology that is characterized by greater refinement and determinacy. However I argue that, contrary to Smolin's claim, an evolutionary account of the laws of nature need not require the abandonment of the relativity of simultaneity as established by the special theory of relativity. I also argue that Lee Smolin and Roberto Unger's characterization of the "original state" in their account of evolutionary cosmology raises philosophical problems of individuation that are best approached from the perspective of Chinese process metaphysics. Finally I turn to the wider consequences of evolutionary cosmology in relation to how we traditionally "rank" fields of knowledge that deal with atemporal structures as "more rigorous" than fields that deal with historical phenomena

    Initial States: IR and Collinear Divergences

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    The standard approach to the infra-red problem is to use the Bloch-Nordsieck trick to handle soft divergences and the Lee-Nauenberg (LN) theorem for collinear singularities. We show that this is inconsistent in the presence of massless initial particles. Furthermore, we show that using the LN theorem with such initial states introduces a non-convergent infinite series of diagrams at any fixed order in perturbation theory.Comment: 4 pages, talk given at Montpellier meeting QCD'06 (to appear in the proceedings
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