String Theory - From Physics to Metaphysics

Currently, string theory represents the only advanced approach to a unification of all interactions, including gravity. In spite of the more than thirty years of its existence it did not make any empirically testable predictions. And it is completely unknown which physically interpretable principles could form the basis of string theory. At the moment, "string theory" is no theory at all, but rather a labyrinthic structure of mathematical procedures and intuitions which get their justification from the fact that they, at least formally, reproduce general relativity and the standard model of elementary particle physics as low energy approximations. However, there are now strong indications that string theory does not only reproduce the dynamics and symmetries of our standard model, but a plethora of different scenarios with different low energy nomologies and symmetries. String theory seems to describe not only our world, but an immense landscape of possible worlds. So far, all attempts to find a selection principle which could be motivated intratheoretically remained without success. So, recently the idea that the low energy nomology of our world, and therefore also the observable phenomenology, could be the result of an anthropic selection from a vast arena of nomologically different scenarios entered string theory. Although multiverse scenarios and anthropic selection are not only motivated by string theory, but lead also to a possible explanation for the fine tuning of the universe, they are concepts which transcend the framework defined by the epistemological and methodological rules which conventionally form the basis of physics as an empirical science.Comment: 30 pages, submitted to "Physics and Philosophy" (Online-Journal

String Theory - Nomological Unification and the Epicycles of the Quantum Field Theory Paradigm

String Theory is the result of the conjunction of three conceptually independent elements: (i) the metaphysical idea of a nomological unity of the forces, (ii) the model-theoretical paradigm of Quantum Field Theory, and (iii) the conflict resulting from classical gravity in a quantum world. String Theory is sometimes assumed to solve this conflict: by means of an application of the model-theoretical apparatus of (perturbative) Quantum Field Theory. But, String Theory does not really solve the conflict. Rather it exemplifies the inadequacy of this model-theoretical apparatus in the context of Quantum Gravity: After several decades of development it still exists only in an essentially perturbative formulation (with minor non-perturbative extensions and vague ideas with regard to a possible non-perturbative formulation). And, due to its quantum field theoretical heritage, it is conceptually incompatible with central implications of General Relativity, especially those resulting from the general relativistic relation between gravity and spacetime. All known formulations of String Theory are background-dependent. On the other hand, it was not even possible to reproduce the Standard Model. Instead, String Theory led to a multitude of internal problems - and to the plethora of low-energy scenarios with different nomologies and symmetries, known as the String Landscape. All attempts to find a dynamically motivated selection principle remained without success, leaving String Theory without any predictive power. The nomological unification of the fundamental forces is only achieved in a purely formal way within the model-theoretical paradigm of Quantum Field Theory - by means of physically unmotivated epicycles like higher dimensionality, Calabi-Yau spaces, branes, etc.Comment: 23 page

Quantum Gravity: Has Spacetime Quantum Properties?

The incompatibility between GR and QM is generally seen as a sufficient motivation for the development of a theory of Quantum Gravity. If - so a typical argumentation - QM gives a universally valid basis for the description of all natural systems, then the gravitational field should have quantum properties. Together with the arguments against semi-classical theories of gravity, this leads to a strategy which takes a quantization of GR as the natural avenue to Quantum Gravity. And a quantization of the gravitational field would in some sense correspond to a quantization of geometry. Spacetime would have quantum properties. But, this strategy will only be successful, if gravity is a fundamental interaction. - What, if gravity is instead an intrinsically classical phenomenon? Then, if QM is nevertheless fundamentally valid, gravity can not be a fundamental interaction. An intrinsically classical gravity in a quantum world would have to be an emergent, induced or residual, macroscopic effect, caused by other interactions. The gravitational field (as well as spacetime) would not have any quantum properties. A quantization of GR would lead to artifacts without any relation to nature. The serious problems of all approaches to Quantum Gravity that start from a direct quantization of GR or try to capture the quantum properties of gravity in form of a 'graviton' dynamics - together with the, meanwhile, rich spectrum of approaches to an emergent gravity and/or spacetime - make this latter option more and more interesting for the development of a theory of Quantum Gravity. The most advanced emergent gravity (and spacetime) scenarios are of an information-theoretical, quantum-computational type.Comment: 31 page

Communications satellite technology

Communications satellite technology - echo, relay, and syncom project

Las Bases Materiales de Nuestras Capacidades Epistemicas. Ensayo de Una Revision Sintetica de la Epistemologia

Tras el fracaso del fundamentalismo epistemológico (que es el fracaso de los ideales de la fundamentación, de la certeza y de la justificación rigurosa de nuestro conocimiento) existen motivos suficientes para una transición de la epistemología pura y analítica a un procedimiento sintético, que integra componentes empírico-científicos en el contexto de la epistemología descriptiva. De una relevancia específica para la cuestión de la realización de nuestros conocimientos son por ejemplo los resultados recientes de las neurociencias. El artículo presenta los primeros resultados de una "neuro-epistemología" constituida con la integración de elementos procedentes de las neurociencias en los problemas de la epistemología.After the breakdown of epistemological fundamentalism (i.e. the ideals of fundamentation, of certainty and of a definitive justification for our knowledge) we have sufficient causes to change the traditional pure and analytic epistemology for a synthetic procedure, which integrates components from the empirical sciences into the context of descriptive epistemology. Of specific relevance for the question of the neurosciences. The article presents the first results of a "neuro-epistemology", hich forms by the integration of elements from the neurosciences into the consideration of the problems of epistemology

Human colour perception. A psychophysical study of human colour perception for real and computer-simulated two-dimensional and three-dimensional objects.

Pontificia Universidad Católica de Valparaís

The Psychological Consequences of COVID- 19: What is the Experience for College Students?

The coronavirus disease, also known as COVID- 19, undoubtedly changed the lives of many American citizens after its initial impact in the United States back in March 2020. A specific proportion of the U.S. population that is often overlooked regarding economic and emotional disparities is that of college students. COVID- 19 has brought about even more changes and issues on top of the preexisting ones that college students already must endure. The purpose of this study was to consider the many variables of college students living during a pandemic. Participants from a Midwestern university completed a series of online surveys measuring demographics and mental health. Hierarchical multiple regression models were used to assess the ability of psychological factors (affect, resilience) to predict symptoms of depression and anxiety after controlling for the influence of life transitions. For both the depression and anxiety models, the total amount of variance explained was 50%, p \u3c .05. Findings showed that despite the experience of challenging life transitions, college students were protected by resilience and positive affect relative to their reported depression and anxiety scores. This study further highlights the importance of maintaining protective factors for managing depression and anxiety, especially when living during a pandemic

International human rights and gender justice in church and society

Paper presented at the Conference on Christian Perspectives on Human Dignity and Humans Rights held in Wuppertal (Germany) online from 9–12 April 202

Quantum Gravity: Motivations and Alternatives

The mutual conceptual incompatibility between GR and QM/QFT is generally seen as the most essential motivation for the development of a theory of Quantum Gravity (QG). It leads to the insight that, if gravity is a fundamental interaction and QM is universally valid, the gravitational field will have to be quantized, not at least because of the inconsistency of semi-classical theories of gravity. If this means to quantize GR, its identification of the gravitational field with the spacetime metric has to be taken into account. And the resulting quantum theory has to be background-independent. This can not be achieved by means of quantum field theoretical procedures. More sophisticated strategies have to be applied. One of the basic requirements for such a quantization strategy is that the resulting quantum theory has GR as a classical limit. - However, should gravity not be a fundamental, but an residual, emergent interaction, it could very well be an intrinsically classical phenomenon. Should QM be nonetheless universally valid, we had to assume a quantum substrate from which gravity would result as an emergent classical phenomenon. And there would be no conflict with the arguments against semi-classical theories, because there would be no gravity at all on the substrate level. The gravitational field would not have any quantum properties, and a quantization of GR would not lead to any fundamental theory. The objective of a theory of 'QG' would instead be the identification of the quantum substrate from which gravity results. - The paper tries to give an overview over the main options for theory construction in the field of QG. Because of the still unclear status of gravity and spacetime, it pleads for the necessity of a plurality of conceptually different approaches to QG.Comment: 32 page