Astrophysics

With the growing body of research on Black Holes, it is becoming increasingly apparent that these celestial objects may have a stronger part to play in the universe than previously thought, shaping galaxies and influencing star formation. In this manuscript, I take these findings a step further, proposing a new set of boundary conditions to both the early and late Universe, extrapolating from thermodynamics. I propose that the Universe will collapse into a massive black hole and that the Big Bang (...) is a result of a collision or interaction between Supra Massive Black Bodies (SMBBs, black holes at the mass scale of our ‘Universe’) of opposite matter type (baryonic and anti-baryonic) and disproportionate masses, a stark departure from the classical Ex-Nihilo creation (from nothing) approach. Such a collision, between a matter and anti-matter SMBB, with disproportionate masses could account for both the explosion referenced as the big bang, as well as the drastic baryonic asymmetry that we observe. Expulsion of black body material from the interaction could also account for Primordial Seed Black holes. (shrink)

In recent years, the hope to confirm the existence of dark matter by experimentally detecting it has diminished significantly. After more than 30 years of experimental searches, many of the most promising candidates have since been ruled out, leaving the epistemic and scientific condition of dark matter in a state of suspension. In efforts to improve the epistemic justification for the dark-matter hypothesis, physicists have turned to philosophical arguments and historical narratives. In this paper, I explicate two such strategies -- (...) explanatory unification and historical continuity -- applied in the context of dark matter. I argue that greater care and attention should be invested in the explanatory arguments to increase their strength, and that a survey of primary historical sources in astronomy renders the historical evidence for the continuity of dark matter substantially weaker. The quality and rigor of the philosophical and historical arguments which physicists are constructing could be substantially improved by increasing interdisciplinary practices. (shrink)

According to the standard interpretation of Einstein’s field equations, gravity consists of mass-energy curving spacetime, and an additional physical force or entity—denoted by Λ (the ‘cosmological constant’)—is responsible for the Universe’s metric-expansion. Although General Relativity’s direct predictions have been systematically confirmed, the dominant cosmological model thought to follow from it—the ΛCDM (Lambda cold dark matter) model of the Universe’s history and composition—faces considerable challenges, including various observational anomalies and experimental failures to detect dark matter, dark energy, or inflation-field candidates. This (...) paper shows that Einstein’s Equivalence Principle entails two possible physical interpretations of General Relativity’s field equations. Although the field equations facially appear to support the standard interpretation—that gravity consists of mass-energy curving spacetime—the field equations can be equivalently understood as holding that gravitational effects instead result from mass-energy accelerating the metric-expansion of a second-order spacetime fabric superimposed upon an absolute, first-order Euclidean space, resulting in the observational appearance of spacetime curvature. This alternative interpretation of relativity is shown to be empirically equivalent to the standard interpretation of relativity, albeit with a changing value for Λ (which is similar to how Λ is understood in the conception of Λ as ‘quintessence’, but in this case takes Λ to be gravity). The reconceptualization is then shown to potentially resolve major observational anomalies for the ΛCDM model, including recent observations conflicting with ΛCDM predictions, as well as failures to directly detect dark matter, dark energy, and inflation field/particle candidates. (shrink)

It is commonly assumed that low-mass primordial black holes cannot constitute a significant fraction of the dark matter in our universe due to their predicted short lifetimes from the conventional Hawking radiation and evaporation process. Assuming physical black holes are nonsingular--likely due to quantum gravity or other high-energy physics--we demonstrate that a large class of nonsingular black holes have finite evaporation temperatures. This can lead to slowly evaporating low-mass black holes or to remnant mass states that circumvent traditional evaporation constraints. (...) As a proof of concept, we explore the limiting curvature hypothesis and the evaporation process of a nonsingular black hole solution in two-dimensional dilaton gravity. We identify generic features of the radiation profile and compare them with known regular black holes, such as the Bardeen solution in four dimensions. Remnant masses are proportional to the fundamental length scale, and we argue that slowly evaporating low-mass nonsingular black holes, or remnants, are viable dark matter candidates. (shrink)

What constitutes a scientific discovery? What role do discoveries play in science, its dynamics and social practices? Must every discovery be attributed to an individual discoverer (or a small number of discoverers)? The paper explores these questions by first critically examining extant philosophical explications of scientific discovery—the models of scientific discovery, propounded by Kuhn, McArthur, Hudson, and Schindler. As a simple, natural and powerful alternative, we proffer the “change-driver model”: in a nutshell, it takes discoveries to be cognitive scientific results (...) that have epistemically advanced science. The model overcomes the shortcomings of its precursors, whilst preserving their insights. We demonstrate its intensional and extensional superiority, especially with respect to the link between scientific discoveries and the dynamics of science, as well as the award system of science. Both as an illustration, and as an application to a recent scientific and political controversy, we apply the considered models of discovery to one of the most momentous discoveries of science: the expansion of the universe. We oppose the 2018 proposal of the International Astronomers’ Union as too simplistic vis-`a-vis the historical complexity of the episode. The change- driver model yields a more nuanced and circumspect verdict: (i) The redshift-distance relation shouldn’t be named the “Hubble-Lemaître Law”, but “Slipher-Lundmark-Hubble-Humason Law”; (ii) Its interpretation in terms of an expanding universe, however, Lemaître ought to be given credit for; but (iii) The establishment of the expansion of the universe, as an evidentially sufficiently warranted result, is a communal achievement, emerging in the 1950s or 1960s. (shrink)

The Schwarzschild solution (Schwarzschild, 1915/16) to Einstein’s General Theory of Relativity (GTR) is accepted in theoretical physics as the unique solution to GTR for a central-mass system. In this paper I propose an alternative solution to GTR, and argue it is both logically consistent and empirically realistic as a theory of gravity. This solution is here called K-gravity. The introduction explains the basic concept. The central sections go through the technical detail, defining the basic solution for the geometric tensor, the (...) Christoffel symbols, Ricci tensor, Ricci scalar, Einstein tensor, stress-energy tensor and density-pressure for the system. The density is integrated, and some consistency properties are demonstrated. A notable feature is the disappearance of the event horizon singularity, i.e. there are no black holes. So far this is for a single central mass. A generalization of the solution for multiple masses is then proposed. This is required to support K-gravity as a viable general interpretation of gravity. Then the question of empirical tests is discussed. It is argued that current observational data is almost but not quite sufficient to verify or falsify K-gravity. The Pioneer spacecraft trajectory data is of particular interest, as this is capable of providing a test; but the data (which originally showed anomalies that match K-gravity) is now uncertain. A new and very practical experiment is proposed to settle the matter. This would provide a novel test of GTR, and a novel test of the cause of the Pioneer anomalies. In conclusion, K-gravity has extensive ramifications for gravitational physics and for the philosophy of GTR and space-time. (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)

We leave in a beautiful and uniform world, a world where everything probable is possible. Since the epic theory of relativity many scientists have embarked in a pursuit of astonishing theoretical fantasies, abandoning the prudent and logical path to scientific inquiry. The theory is a complex theoretical framework that facilitates the understanding of the universal laws of physics. It is based on the space-time continuum fabric abstract concept, and it is well suited for interpreting cosmic events. However, it is not (...) well suited for handling of small, local topics as global warming, local energy issues, and overall common humanity matters. We now forward may fancy theories and spend unimaginable effort to validate them, even when we are perhaps headed in a wrong direction. For example, in our times matters of climate changes are debated by politicians based on economical considerations that are as illogical as they come. The venerable paths of scientific method developed during centuries by prominent scientists and philosophers has been willingly ignored and abandoned for various and prejudiced purpose. 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)

An orbital simulation program is described that uses a geometrical approach to modeling gravitational and atomic orbits at the Planck scale. Orbiting objects A, B, C... are sub-divided into points, each point representing 1 unit of Planck mass, for example, a 1kg satellite would divide into 1kg/Planck mass = 45940509 points. Each point in object A then forms a rotating orbital pair with every corresponding point in objects B, C... resulting in a universe-wide, n-body network of rotating point-to-point orbital pairs. (...) Each orbital pair rotates 1 unit of Planck length per unit of Planck time at velocity c in hypersphere space co-ordinates, the results are then summed and averaged to give the new co-ordinates, the program then repeats. When these rotations are mapped over time on a 2-D plane (representing 3D space), objects A, B, C... appear to be orbiting each other. The basic simulation uses the fine structure constant alpha as an orbital constant to simulate gravitational orbit parameters. As each orbital comprises only 2 points, 1 at each orbital pole, information regarding the objects A, B, C... ; momentum, size, center of mass, barycenter etc ... is not required, instead only the start (x, y, z) co-ordinates of each point are defined. Each point, by having a mass of Planck mass, is itself a construct of multiple particles, and so we can also form individual particle to particle orbital pairs. The simulation uses only geometry, no dimensioned constants (G, h, c ...) are required, although the results can be measured in Planck units for comparison. Points are physically linked together by a unit of momentum (a graviton), the rationale for this is described in a subsequent article on atomic orbitals. (shrink)

In this article, a classification of the global catastrophic risks connected with the possible existence (or non-existence) of extraterrestrial intelligence is presented. If there are no extra-terrestrial intelligences (ETIs) in our light cone, it either means that the Great Filter is behind us, and thus some kind of periodic sterilizing natural catastrophe, like a gamma-ray burst, should be given a higher probability estimate, or that the Great Filter is ahead of us, and thus a future global catastrophe is high probability. (...) If ETIs exist in our light cone, it is most likely they exist in the form of ET artificial general intelligence (ETAI). ETAI may be traveling at near-light speed as an explosive wave of intelligence in the form of some nano-mechanisms which could reach us at any moment; may send us potentially dangerous messages with AI-virus payloads; or be near or on Earth in some dormant form. This dormant form could be nanobots, which could act as berserkers, and be triggered when humans unwittingly cross some threshold. If ETIs are nearby and less advanced, they could find our messaging extra-terrestrial intelligence (METI) messages and send their “fleet” to or direct weapons toward Earth. Even extinct ETIs could have left dangerous remnants in the form of AI systems that our civilization may encounter. If our existence is a simulation, this could be run by ETIs. Even a false belief in the existence of ETIs could potentially fuel millennial sects. If humanity is the first intelligence to emerge, it may kill or prevent the existence of all future potential ETI, a different type of catastrophe. Several options to prevent catastrophic risks are connected with ETI: sending requests for help, using random strategies to escape the Fermi paradox, Great Filter prediction, or the hope that ETIs will find the remains of our extinct civilization and resurrect it. (shrink)

Abstract. The presumptuous philosopher (PP) thought experiment lends more credence to the hypothesis which postulates the existence of a larger number of observers than other hypothesis. The PP was suggested as a purely speculative endeavor. However, there is a class of real world observer-selection effects where it could be applied, and one of them is the possibility of interstellar panspermia (IP). There are two types of anthropic reasoning: SIA and SSA. SIA implies that my existence is an argument that larger (...) total number of observers exists; SSA implies that I should find myself in a region with larger number of observers. However, as S. Armstrong showed, SIA can’t distinguish between different ways how larger number of observers appeared, so it can’t favor IP compared with other ways to get many observers. SSA application here is less controversial as it tells only about relation between regions size: e.g. I am more likely to live in a larger country than in a small one, conditioning that the total number of small countries is also small. Anthropic considerations suggest that the universes in the multiverse with interstellar panspermia will have orders of magnitude more civilizations than universes without IP, and thus we are likely to be in such a universe. This is a strong counterargument against a variant of the Rare Earth hypothesis based on the difficulty of abiogenesis: even if abiogenesis is difficult, IP will disseminate life over billions of planets, meaning we are likely to find ourselves in a universe where IP has happened. This implies that there should be many planets with life in our galaxy, and renders the Fermi paradox even sharper. Either the Great Filter is ahead of us and there are high risks of anthropogenic extinction, or there are many alien civilizations nearby and of the same age as ours—which is itself a global catastrophic risk, as in that case the wave of alien colonization could arrive between 25-500 ky from now. -/- . (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)

This report offers a modern perspective on the problem of negative energy, based on a reexamination of the concept of time direction as it arises in a classical and quantum-mechanical context. From this analysis emerges an improved understanding of the general-relativistic stress-energy of matter as being a manifestation of local variations in the energy density of zero-point vacuum fluctuations. Based on those developments, a set of axioms is proposed from which are derived generalized gravitational field equations which actually constitute a (...) simplification of relativity theory in the presence of negative-energy matter and a non-zero cosmological constant. Important clarifications are also achieved regarding the nature of the binary degrees of freedom of matter in the final stages of a gravitational collapse. Those results are then applied to provide original solutions to several long-standing problems in cosmology, including the problem of the nature of dark matter and dark energy, that of the origin of thermodynamic time asymmetry, and several other issues traditionally approached using inflation theory. Finally, we draw on those developments to provide significant new insights into the foundations of quantum theory, regarding, in particular, the problem of quantum non-locality, that of the emergence of time in quantum cosmology, as well as the question of the persistence of quasiclassicality following decoherence. (shrink)

The use of statistical methods to model gravitational systems is crucial to physics practice, but the extent to which thermodynamics and statistical mechanics genuinely apply to these systems is a contentious issue. This paper provides new conceptual foundations for gravitational thermodynamics by reconsidering the nature of key concepts like equilibrium and advancing a novel way of understanding thermodynamics. The challenges arise from the peculiar characteristics of the gravitational potential, leading to non-extensive energy and entropy, negative heat capacity, and a lack (...) of standard equilibrium. Hence it has been claimed that only non-equilibrium statistical mechanics is warranted in this domain, whereas thermodynamics is inapplicable. We argue instead that equilibrium statistical mechanics applies to self-gravitating systems at the relevant scale, as they display equilibrium in the form of metastable quasi-equilibrium states. We then develop a minimal framework for thermodynamics that can be applied to these systems and beyond. Thermodynamics applies in the sense that we can devise macroscopic descriptions and explanations of the behaviour of these systems in terms of coarse-grained quantities like energy and temperature within equilibrium statistical mechanics. (shrink)

The use of statistical methods to model gravitational systems is crucial to physics practice, but the extent to which thermodynamics and statistical mechanics genuinely apply to these systems is a contentious issue. This paper provides new conceptual foundations for gravitational thermodynamics by reconsidering the nature of key concepts like equilibrium and advancing a novel way of understanding thermodynamics. The challenges arise from the peculiar characteristics of the gravitational potential, leading to non-extensive energy and entropy, negative heat capacity, and a lack (...) of standard equilibrium. Hence it has been claimed that only non-equilibrium statistical mechanics is warranted in this domain, whereas thermodynamics is inapplicable. We argue instead that equilibrium statistical mechanics applies to self-gravitating systems at the relevant scale, as they display equilibrium in the form of metastable quasi-equilibrium states. We then develop a minimal framework for thermodynamics that can be applied to these systems and beyond. Thermodynamics applies in the sense that we can devise macroscopic descriptions and explanations of the behaviour of these systems in terms of coarse-grained quantities like energy and temperature within equilibrium statistical mechanics. (shrink)

David Kinnebrook is remembered as the assistant to the Astronomer Royal dismissed in 1796 for marking stellar transits too slowly. Kinnebrook’s firing is commonly listed as the origin point for the personal equation and empirical psychology. Historians have viewed Kinnebrook as a slightly misused, though mute, party in the affair, drawing their accounts from Nevil Maskelyne’s published account of the dismissal. Kinnebrook’s letters, which resurfaced in 1985, detail a months-long dispute with Maskelyne concerning observational disagreements. The letters provide an account (...) of observational practice and individual differences in marking transits; they also detail Maskelyne’s failure to recognize an epistemic problem. Kinnebrook’s letters show that the problem of individual differences was known to Maskelyne as well as several of his contemporaries. Evidence from the letters shows that Maskelyne passed off six weeks of observations collected by his disgraced assistant as his own. The letters also state that Maskelyne had substantial personal observational differences with previous assistants. While Bessel later conjectured that Kinnebrook was under pressure to speed up his observations, Kinnebrook’s letters confirm that conjecture and reveal that Kinnebrook had a deeper comprehension of the epistemological problems of observation than has been recognized. Kinnebrook’s recognition of personal differences in marking stellar transits is a significant moment in the prehistory of the personal equation. (shrink)

Since the emergence of New Atheism under figures such as Richard Dawkins, there has been a revolution in popular Christian interest in science and religion. However, many approaches to science and religion among Christian laypeople follow an evidentialist model. In sharp contrast, Sir Arthur Eddington’s different voice, as a prominent scientist and devout Quaker, remains unfamiliar to the majority in these discussions. Heralded by some commentators as ahead of his time, his unusual yet bold ideas, which at times were misunderstood, (...) deserve renewed consideration. His influence throughout the twentieth century ran deeper than he has been given credit for. It is time to reassess his value to science and religion as a discipline and to acknowledge that his contributions have a great deal of merit for the ongoing dialogue. In this article, we question whether evidentialist approaches are as valuable as Eddington’s contributions. We examine his works and life to see what can be learned from his perspective on the science-religion question. In doing so, we are also asking whether his attitude to science and religion would be more fruitful than the alternatives. (shrink)

Sir Arthur Eddington (1882-1944) was a prominent Quaker astrophysicist at Cambridge University who made an extraordinary impact on inter-war physics, helping to communicate relativity, cosmology and quantum physics to a popular audience. He was also a prolific science communicator whose philosophical reflections on the meaning of the new physics captivated global audiences. His quest for a theory of everything, though unsuccessful, came from his conviction that the nature of ultimate reality was spiritual, and is underappreciated for its historical impact. Much (...) can be learned from his legacy of trying to harmonize science and faith to a larger audience searching for meaning. Eddington’s ambitious attempt at a Christian theory of everything deserves further examination and can still teach us much about our approach to science and religion. (shrink)

● Este ensayo corre el velo de una estrecha relación entre los símbolos astrológicos y el mundo fenoménico y explica cómo dicotomías características de los siglos XVIII y XX han dificultado esta y otras comprensiones de nuestra realidad. ● Las observaciones se apoyan en los hallazgos producidos durante los últimos cuarenta años con relación a los planetas, sus características astronómicas y propiedades astrofísicas, hallazgos que corroboran casi integralmente los esbozos que sobre los planetas hiciera, entre otros autores, VETIO VALENTE (s. (...) II a.C.) en su afamada Antología. ● Como el sol alcanza su mayor fuerza durante el verano y su menor fuerza durante el invierno, también el resto de los miembros de nuestro sistema solar cobran fuerzas en diferentes segmentos de la eclíptica, contribuyendo en matices específicos de las condiciones del clima en diferentes épocas, lo que nutre las significaciones (o propiedades) zodiacales. ● Apoyándonos en hechos constatados por la física y el magnetismo molecular, defendemos la eclíptica (Zodiaco) como una realidad físico química cuyos doce segmentos afianzan o menoscaban el poder aparentemente electromagnético de algunos planetas con relación a la Tierra en diferentes épocas según la revolución solar de cada uno. ● Con el fin de favorecer la comprensión, prejuicios comunes necesitan ser tratados, y de ahí los tres acápites que componen la introducción del ensayo, uno de los cuales aborda un recurso del lenguaje, la alegoría, con el fin de demostrar su recurrente necesidad tanto en el pasado como en el presente sin que dicha práctica constituya una infidelidad fenoménica. ● Por último, ofrecemos la explicación más plausible producida hasta ahora sobre el mecanismo de acción responsable de la astrología, es decir, de la influencia de los cuerpos celestes (más allá de la luna y del sol) sobre la vida en la Tierra: «quantum entanglement», o la “acción misteriosa a distancia” incrédulamente formulada por EINSTEIN en 1935, cuya comprobación les ganó el Premio Nobel de Física 2022 a ANTON ZEILINGER y JOHN CLAUSER. ● Utilizamos un número considerable de ilustraciones a los fines de apoyar la comprensión del lector, que puede no ser astrólogo sino un curioso, y esperamos que sean más los curiosos que los astrólogos, especialmente si hacen parte de la comunidad científica. (shrink)

Philosophers and scientists have often adopted the orthodox version of calibration which involves standardizing an instrument using a known phenomenon. The essential link between theoretical concepts and empirical data, in the philosophy of measurement, has generated the formulation of principles of coordination, synthetic a priori, and revisables. Operationalist thinking wanted to limit the scope of concepts to operations of measurement that are actually achievable. The coherentist perspective in the philosophy of measurement has operated a recovery of coordinationist epistemology and operationalism, (...) relying on a minimal number of ontological principles. Models of an instrument involve a commitment to separation between idealized theories and material things. However, philosophers and metrologists have advocated the requirement of a rich theoretical content in the modeling of measuring instruments. According to other contributions, the epistemic privilege of measurement precedes a background theory and its robustness lies in the free contact with empirical data. Moreover, the applicability regime of a theory dictates its boundary conditions, which guide the experimenter in the design of measuring instruments and provide the basis for operationalizing the meaning of theoretical terms. I support operational pluralism, measurement operations involving different physical indicators, accompanied by dynamic coherentism. The James Webb Space Telescope calibration program is a significant case. Observations of calibration stars by various methods are used to calculate the factors that convert a measurement in instrumental units to physical units. (shrink)

What happens when disturbances in precision measurement instruments are indecipherable to physicists despite extensive review of the instruments and their outputs? How do physicists parse instrument outputs to discern sought-after signals from noise that originates from the surrounding natural and built environments, either masking or mimicking these desired signals? I argue that given the extreme sensitivity of the laser interferometers used by the Laser Interferometer Gravitational-Wave Observatory (LIGO) to detect minute length deformations caused by gravitational waves, physicists reconceptualized their traditional (...) laboratory spaces to include the surrounding natural and built environments. Discerning signal from noise in instruments operating close to their low noise floors necessitate an epistemic shift that combines the laboratory with the surrounding natural and built environments beyond its walls through the epistemic space of the “expanded laboratory environment.”. (shrink)

The central aim of astrobiology is to study origins, evolution and distribution of life in the universe, combining data from various disciplines. However, I will argue that from a philosophical standpoint, astrobiology requires the affirmation of astrophilosophy. Fry (2015) claims that philosophical presuppositions guiding science are general, for example, we hold the notion that natural laws necessarily hold at the whole universe at large, and on the basis of the universal applicability of natural laws, the astrobiological research is conducted. Jakosky (...) (2000) mentions that finding any life elsewhere that had an origin independent of that on Earth would be philosophically profound. Kolb (2005) covers various definitions of life and establishes thought experiments about the survival of life in the Solar System. Most of the (scarce) research has dealt with specific philosophical topics in astrobiology, instead of seeing it as a new philosophical discipline or perhaps a new subdiscipline for each of the classical philosophical disciplines. -/- Persson (2013) has made a step towards this by systematizing the most important philosophical questions in astrobiology, along with Dunér (2013) emphasizing its importance for ethics, epistemology, semiotics and linguistics, and cognition. Persson mentions that the justification of resources is a question of ethics, but I would also like to add political philosophy, since not only is there a question of preference over "earthly manners" but also fair distribution of costs and the concept of ownership of the new worlds. The question of a new definition of life is another one, that I would argue holds one of the central places in metaphysics. Persson mentions various definitions of life and that such a discussion is important for both biology and philosophy, a notion I would like to add to by stating that the question of finding another life is also an ontological question, giving us either categorical similarity or dissimilarity, and establishing a new kind, which is of metaphysical importance. Persson also establishes the importance of is it possible to know whether we are alone or not, a question I would like to tie to the modern epistemological questions of possibility of knowledge (cf. Cassam, 2007). Persson also connects astrobiology with ethical questions such as biocentrism or colonization, which also might be tied to philosophy of mind, and philosophy of politics and culture respectively. -/- One major step forward was established recently by Dick (2020), focusing on a new discipline combining astronomy, cosmology, and astrobiology, in which there is a focus on the nature of reasoning, the problematic nature of evidence, the influence of metaphysical preconceptions, the epistemological status of these disciplines, the role of technology, and the mutual interaction between these disciplines. The purpose of this paper is to see how the creation of astrophilosophy could better emphasize the role of philosophy today, and would it behave as a side-by-side major philosophical discipline or a complement to the current philosophical disciplines, for example, bringing new light into metaphysics, epistemology, ethics, or philosophy of mind. In the first case, we would make a metaphysical difference between human-related problems and other possible kinds, and in the second case, we would have to incorporate current astrobiological questions into modern philosophical dialogue, establishing, for example, metaphysics and epistemology of life, or, a possibility to incorporate non-human life into epistemology, philosophy of mind, and philosophy of biology. This goes hand to hand with Dunér's (2013) points of seeing the philosophy of astrobiology as both a type of individual and collective self-understanding, and conceptual analysis. That way, using astrophilosophical novelties, we can improve not only our current philosophical intuitions, but also expand the territory of philosophical subdisciplines to become more universal. -/- . (shrink)

The ongoing debate in philosophy of science over whether simulations are experiments has so far operated at too high a level of generality. I revisit this discussion in the context of simulation in astronomy and astrophysics, arguing that a specific subclass of simulations that include a significant amount of empirically obtained temporal data count as experiments. This subclass will be a small one, as the majority of simulations in astronomy and astrophysics will still suffer from a sparseness of data. But (...) it remains the case that there exist examples of simulations that are experiments. (shrink)

Astrophysics is a scientific field with a rich ontology of individual processes and general phenomena that occur in our universe. Despite its central role in our understanding of the physics of the universe, astrophysics has largely been ignored in the debate on scientific realism. As a notable exception, Hacking (Philos Sci 56(4):555–581, 1989) argues that the lack of experiments in astrophysics forces us to be anti-realist with respect to the entities which astrophysics claim inhabit the universe. In this paper, I (...) investigate the viability of astrophysical realism about black holes, given other formulations of entity realism, specifically Cartwright’s (How the Laws of Physics Lie. Oxford University Press, 1983), and Chakravartty’s (A Metaphysics for Scientific Realism: Knowing the Unobervable. Cambridge University Press, 2007) versions of entity realism. I argue that on these accounts of entity realism, you cannot be a realist with respect to black holes, and likewise, if you want to be a realist about black holes, you cannot be an entity realist of these particular strands. (shrink)

Astrophysics is often cast as an observational science, devoid of traditional experiments, along with astronomy and cosmology. Yet, a thriving field of experimental research exists called laboratory astrophysics. How should we make sense of this apparent tension? I argue that approaching the epistemology of astrophysics by attending to the production of empirical data and the aims of the research better illuminates both the successes and challenges of empirical research in astrophysics than evaluating the epistemology of astrophysics according to the presence (...) or absence of experiments. (shrink)

We discuss three philosophically interesting epistemic peculiarities of black hole astrophysics: (1) issues concerning whether and in what sense black holes do exist; (2) how to best approach multiplicity of available definitions of black holes; (3) short (i.e., accessible within an individual human lifespan) dynamical timescales present in many of the recent, as well as prospective, observations involving black holes. In each case we argue that the prospects for our epistemic situation are optimistic.

The LIGO-Virgo Collaboration achieved the first ‘direct detection’ of gravitational waves in 2015, opening a new “window” for observing the universe. Since this first detection (‘GW150914’), dozens of detections have followed, mostly produced by binary black hole mergers. However, the theory-ladenness of the LIGO-Virgo methods for observing these events leads to a potentially-vicious circularity, where general relativistic assumptions may serve to mask phenomena that are inconsistent with general relativity (GR). Under such circumstances, the fact that GR can ‘save the phenomena’ (...) may be an artifact of theory-laden methodology.This paper examines several ways that the LIGO-Virgo observations are used in theory and hypothesis testing, despite this circularity problem. First, despite the threat of vicious circularity, these experiments succeed in testing GR. Indeed, early tests of GR using GW150914 are best understood as a response to the threat of theory-ladenness and circularity. Each test searches for evidence that LIGO-Virgo’s theory-laden methods are biasing their overall conclusions. The failure to find evidence of this places constraints on deviations from the predictions of GR. Second, these observations provide a basis for studying astrophysical and cosmological processes, especially through analyses of populations of events. As gravitational-wave astrophysics transitions into mature science, constraints from early tests of GR provide a scaffolding for these population-based studies. I further characterize this transition in terms of its increasing connectedness to other parts of astrophysics and the prominence of reasoning about selection effects and other systematics in drawing inferences from observations.Overall, this paper analyses the ways that theory and hypothesis testing operate in gravitational-wave astrophysics as it gains maturity. In particular, I show how these tests build on one another in order to mitigate a circularity problem at the heart of the observations. (shrink)

Observational astronomy is plagued with selection effects that must be taken into account when interpreting data from astronomical surveys. Because of the physical limitations of observing time and instrument sensitivity, datasets are rarely complete. However, determining specifically what is missing from any sample is not always straightforward. For example, there are always more faint objects (such as galaxies) than bright ones in any brightness-limited sample, but faint objects may not be of the same kind as bright ones. Assuming they are (...) can lead to mischaracterizing the population of objects near the boundary of what can be detected. Similarly, starting with nearby objects that can be well observed and assuming that objects much farther away (and sampled from a younger universe) are of the same kind can lead us astray. Demographic models of galaxy populations can be used as inputs to observing system simulations to create “mock” catalogues that can be used to characterize and account for multiple, interacting selection effects. The use of simulations for this purpose is common practice in astronomy, and blurs the line between observations and simulations; the observational data cannot be interpreted independent of the simulations. We will describe this methodology and argue that astrophysicists have developed effective ways to establish the reliability of simulation-dependent observational programs. The reliability depends on how well the physical and demographic properties of the simulated population can be constrained through independent observations. We also identify a new challenge raised by the use of simulations, which we call the “problem of uncomputed alternatives.” Sometimes the simulations themselves create unintended selection effects when the limits of what can be simulated lead astronomers to only consider a limited space of alternative proposals. (shrink)

It is generally accepted that science sometimes involves reasoning with analogies. Often, this simply means that analogies between disparate objects of study might be used as heuristics to guide theory development. Contemporary black hole physics, however, deploys analogical reasoning in a way that seems to overreach this traditional heuristic role. In this chapter, I describe two distinct pieces of analogical reasoning that are quite central to the contemporary study of black holes. The first underpins arguments for the existence of astrophysical (...) Hawking radiation, and the second underpins arguments for black holes being ‘genuinely’ thermodynamical in nature. I argue that while these are distinct analogical arguments, they depend on one another in an interesting way: the success of the second analogical argument presupposes the success of the first. This induces a tension for those who wish to take black hole thermodynamics seriously, but who are sceptical of the evidence provided for astrophysical Hawking radiation by the results of analogue gravity. I consider three ways to resolve this tension, and show that each fails. (shrink)

This is an open access book. This book, the first edited collection of its kind, explores the recent emergence of philosophical research in astrophysics. It assembles a variety of original essays from scholars who are currently shaping this field, and it combines insightful overviews of the current state of play with novel, significant contributions. It therefore provides an ideal source for understanding the current debates in philosophy of astrophysics, and it offers new ideas for future cutting-edge research. The selection of (...) essays offered in this book addresses methodological and metaphysical questions that target a wide range of topics, including dark matter, black holes, astrophysical observations and modelling. The book serves as the first standard resource in philosophy of astrophysics for all scholars who work in the field and want to expand or deepen their knowledge, but it also provides an accessible guide for all those philosophers and scientists who are interested in getting a first, basic understanding of the main issues in philosophy of astrophysics. (shrink)

Next-generation observational surveys in astronomy provide empirical data with increasingly high resolution and precision. After presenting the basic methods of population synthesis (via Conroy 2013 and Maraston 2005), this paper argues for several related conclusions. The increased precision of the new methods requires the development of improved theoretical resources and models to provide the richest interpretation of the new data (as argued by Maraston and Strömbäck, 2011). The measurement of physical variables and parameters in population synthesis is best understood using (...) a model-based account along the lines of (Tal 2012) and (Parker 2017). Finally, in the case of population synthesis, improved empirical data does not dispense with the need for theoretical reasoning in post-data analysis. In fact, the high-resolution data used in next-generation population synthesis demands ever richer theories and models, a process that results in hybrid enrichment of theoretical and observational methods and results. (shrink)

Systems of differential equations are used to describe, model, explain, and predict states of physical systems. Experimental and theoretical branches of physics including general relativity, climate science, and particle physics have differential equations at their center. Direct solutions to differential equations are not available in many domains, which spurs on the use of creative mathematics and simulated solutions.

Henri Poincaré a découvert dans les années 1880 une figure d’équilibre d’une masse fluide en rotation uniforme: la figure piriforme, ou la poire. Il considérait que la poire était susceptible de se diviser en deux parties inégales, et que son évolution pouvait expliquer la genèse des étoiles binaires. Les études photométriques et spectroscopiques des étoiles variables de cette période ont donné lieu à la modélisation en étoiles binaires à éclipses, ce qui renforçait l’interprétation réaliste des figures d’équilibre – y compris (...) la poire – dans le domaine cosmique. Cet article propose une analyse de l’interprétation astrophysique de la poire de Poincaré et de la théorie de Poincaré-Darwin sur la genèse des étoiles binaires par fission, en regard des recherches sur les étoiles variables réalisées entre 1885 et 1901. (shrink)

The philosophy of historical sciences investigates their distinct objects of study, epistemic challenges, and methodological solutions. Rethinking astronomy in this light offers a contribution. First, the methodology of historical sciences adds to a more adequate description of how astronomers study and utilize token events. Second, astronomy faces a typical difficulty in identifying traces of some past events and has developed a delicate solution. This enriches the idea of trace and suggests a methodology that relies on iterations between data-driven approaches and (...) theory-driven approaches, together with the cross-validation between multiple relevant historical events or datasets. (shrink)

This dissertation is concerned with two of the largest questions that we can ask about the nature of physical reality: first, whether physical reality begin to exist and, second, what criteria would physical reality have to fulfill in order to have had a beginning? Philosophers of religion and theologians have previously addressed whether physical reality began to exist in the context of defending the Kal{\'a}m Cosmological Argument (KCA) for theism, that is, (P1) everything that begins to exist has a cause (...) for its beginning to exist, (P2) physical reality began to exist, and, therefore, (C) physical reality has a cause for its beginning to exist. While the KCA has traditionally been used to argue for God's existence, the KCA does not mention God, has been rejected by historically significant Christian theologians such as Thomas Aquinas, and raises perennial philosophical questions -- about the nature and history of physical reality, the nature of time, the nature of causation, and so on -- that should be of interest to all philosophers and, perhaps, all humans. While I am not a religious person, I am interested in the questions raised by the KCA. In this dissertation, I articulate three necessary conditions that physical reality would need to fulfill in order to have had a beginning and argue that, given the current state of philosophical and scientific inquiry, we cannot determine whether physical reality began to exist. -/- Friends of the KCA have sought to defend their view that physical reality began to exist in two distinct ways. As I discuss in chapter 2, the first way in which friends of the KCA have sought to defend their view that physical reality began to exist involves a family of a priori arguments meant to show that, as a matter of metaphysical necessity, the past must be finite. If the past is necessarily finite, then the past history of physical reality is necessarily finite. And if having a finite past suffices for having a beginning, then, since the past history of physical reality is necessarily finite, physical reality necessarily began to exist. I show that the arguments which have been offered thus far for the view that the past is necessarily finite do not succeed. Moreover, as I elaborate on in chapter 5, having a finite past does not suffice for having a beginning. -/- As I discuss in chapter 3, the second way in which friends of the KCA have sought to defend their view that physical reality began to exist involves a family of a posteriori arguments meant to show that we have empirical evidence that physical reality has a finite past history. For example, the big bang is sometimes claimed to have been the beginning of physical reality and, since we have excellent empirical evidence for the big bang, we have excellent empirical evidence for the beginning of physical reality. The big bang can be understood in two ways. On the one hand, the big bang can be understood as a theory about the history and development of the observable universe. Understood in that sense, then I agree that the big bang is supported by excellent empirical evidence and by a scientific consensus. On the other hand, some authors (particularly science popularizers, science journalists, and religious apologists) have wrongly interpreted big bang theory as a theory about the beginning of the whole of physical reality. As I argue, while a beginning of physical reality may be consistent with classical big bang theory, classical big bang theory does not provide good reason for thinking that physical reality began to exist. -/- In part II, I turn to discussing three necessary, but not necessarily sufficient, conditions for physical reality to have a beginning. Before discussing the three conditions, in chapter 4, I introduce three metaphysical accounts of the nature of time (A-theory, B-theory, and C-theory) as well as some formal machinery that will subsequently become useful in the dissertation. I introduce the first of the three conditions in chapter 5. According to the Modal Condition, physical reality began to exist only if, at the closest possible worlds without time, physical reality does not exist. I show that this condition helps us to make sense of various views in both theology and philosophy of physics. In chapter 6}, I introduce the second of my three conditions, the Direction Condition, according to which, roughly, physical reality began to exist only if all space-time points agree about the direction of time, so that all space-time points can agree that physical reality's putative beginning took place in their objective past. In chapter 7, I discuss the third condition, the Boundary Condition, according to which physical reality began to exist only if there is a past temporal boundary such that physical reality did not exist before the boundary. I show that there are two senses in which physical reality could be said to have had a past temporal boundary. Lastly, in chapter 8, I show that there is a relationship between my three conditions and classical big bang theory, even though the relationship is not the one usually identified in the literature. -/- In part III, I present four arguments for the view that, at the present stage of philosophical and scientific inquiry, we cannot know whether physical reality satisfies the three necessary conditions to have had a beginning and, consequently, we cannot know whether physical reality had a beginning. As I will prove in chapter 9, no set of observations that we currently have, when conjoined with General Relativity, entails that physical reality satisfies the Direction or Boundary Conditions. As I show in chapter 10, considerations in the philosophical foundations of statistical mechanics entail either that the Cosmos violates the Modal Condition or else that there is a transcendental condition on the possibility of our knowledge of the past that prevents our access to data we would need to gather to determine whether physical reality satisfies the Boundary Condition. In chapter 11, I show that there are a number of live cosmological models according to which physical reality does not satisfy the Boundary Condition. As long as we don't know whether any of those cosmological models are correct, we do not know whether physical reality satisfies the Boundary Condition. Lastly, I turn to confirmation theory and show that, at our present stage of inquiry, ampliative inferences for the conclusion that physical reality satisfies the Modal, Direction, and Boundary Conditions are not successful. (shrink)

Typical cosmological models are based on the postulate that space is homogeneous. Space however contains overdense regions in which matter is concentrating, leaving underdense regions of almost void. The evolution of the scale factor of the universe has been established from measurements on SNIa. Since such events occur in regions were matter is present, we may expect that most of the SNIa are located in overdense regions. This means that the evolution of the scale factor has been established in a (...) biased manner, by considering only information coming from overdense regions, excluding the one from the underdense regions. We develop a simple model to analyze the effect of this bias, and show that it leads to the appearance of a new tensor in the Einstein equation of general relativity, which can account for the apparent acceleration of the expansion of the universe. We further show that this tensor tends to be proportional to the FLRW metric tensor, and that the constant of proportionality quantitatively corresponds to the measured cosmological constant. We finally discuss the applicability of the bias to other probes used in determining the dynamics of the universe. (shrink)

This book presents fresh insights into analogue quantum simulation. It argues that these simulations are a new instrument of science. They require a bespoke philosophical analysis, sensitive to both the similarities to and the differences with conventional scientific practices such as analogical argument, experimentation, and classical simulation. -/- The analysis situates the various forms of analogue quantum simulation on the methodological map of modern science. In doing so, it clarifies the functions that analogue quantum simulation serves in scientific practice. To (...) this end, the authors introduce a number of important terminological distinctions. They establish that analogue quantum ‘computation' and ‘emulation' are distinct scientific practices and lead to distinct forms of scientific understanding. The authors also demonstrate the normative value of the computation vs. emulation distinction at both an epistemic and a pragmatic level. -/- The volume features a range of detailed case studies focusing on: i) cold atom computation of many-body localisation and the Higgs mode; ii) photonic emulation of quantum effects in biological systems; and iii) emulation of Hawking radiation in dispersive optical media. Overall, readers will discover a normative framework to isolate and support the goals of scientists undertaking analogue quantum simulation and emulation. This framework will prove useful to both working scientists and philosophers of science interested in cutting-edge scientific practice. (shrink)

What if someone asked you to keep a four-kilometer-long ruler absolutely still so that you could measure deformations of length of ~1x10^-18m using light? On September 14, 2015, physicists and engineers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) accomplished this absurd feat when they first detected gravitational wave signals—the result of the most violent events in our universe, such as the collision of two black holes—using two immense L-shaped instruments with arms four-kilometers in length and placed in what seemed to (...) be the middle of nowhere. -/- The focus of this dissertation centers on how scientists must have an intricate understanding of the environment surrounding LIGO’s instruments to understand the vast and active universe through the detection of gravitational waves. I explore how LIGO physicists and engineers constructed stillness to distinguish the surrounding natural and built environment from gravitational wave signals. I explore how the pre-LIGO and LIGO laboratory spaces became an expanded laboratory extending as an overlay into the surrounding environment and beyond. I show that the metes and bounds of the expanded laboratory are defined by what the interferometers are sensitive to. I further explore how physicists, engineers, and data scientists theorized an experiment that required such an extreme sensitivity (i.e., imagining stillness), developed methods to investigate, understand, and abate noise, disturbances, and aberrations (i.e., engineering stillness), found sites with minimal noise profiles, both physical and social, that would accommodate the size and function of the instruments despite land uses in conflict with the experiment (i.e., finding stillness), and understood the overlapping human and non-human uses of the land that jeopardized the ability to make these highly precise detections and mediate solutions that would allow for concurrent use of the land (i.e., negotiating stillness). -/- Through this history, I conclude that the level of sensitivity the physicists and engineers can attain in the LIGO interferometers is predicated on constructed stillness. This determines the instruments’ ability to measure the minute deformations in length caused by gravitational waves such that the physicists, engineers, and data scientists can rule out the geography of noise and make the claim that the heterogeneity of their locations at Hanford and Livingston does not negate their assertion of twin detections of gravitational wave signals across their two sites. (shrink)

We envisage a black hole perturbed by a force-free magnetic field outside and attempt to determine its structure. We suppose the metric that describes this black hole is of the static spherical type, that is Schwarzschild, and the energy–momentum tensor emanating from an FFMF source perturbs this background metric, in this regard one can imagine a magnetic accretion disk around the black hole. By solving the equations for such a configuration, we will show that in addition to modifying the diagonal (...) elements of the background metric, we will also see the non-zeroing of the off-diagonal elements of the general metric, one of the immediate consequences of which will be a static to stationary transition. (shrink)

Bas van Fraassen maintains that the actual function of optical instruments is producing images. Still, the output of a telescope is different from that of a microscope, for in the latter case it is not possible to empirically investigate the geometrical relations between the observer, the image and the detected entity, while in the former it is - at least in principle. In this paper I argue that this is a weak argument to support the belief in the existence of (...) exoplanets that, according to van Fraassen, comes with accepting a theory that posits these entities. If a constructive empiricist asserts the empirical adequacy of such a theory, she might be relying on typical realist arguments, instead - of the very same ilk as the ones used to defend the veridicality of microscopic images. Perhaps the time has come for van Fraassen to explain his view on telescopes. (shrink)

Astrobiology is premised on the idea that life beyond Earth can exist. Yet, everything known about life is derivative from life on Earth. To understand life beyond Earth, then, requires a definition of life that is abstracted beyond a particular geophysical context. To do this requires a formal understanding of the physical mechanisms by which matter is animated into life. At current, such descriptions are completely lacking for the emergence of life, but do exist for the emergence of consciousness. Namely, (...) contemporary neuroscience offers definitions for universal physical processes that are in one-to-one correspondence with conscious experience. Since consciousness is a sufficient condition for life, these universal definitions of consciousness offer an interesting way forward in terms of the search for life in the cosmos. In this work, I systematically examine Integrated Information Theory (IIT), a well-established theory of consciousness, with the aim of applying it in both biological and astrobiological settings. Surprisingly, I discover major problems with Integrated Information Theory on two fronts: mathematical and epistemological. On the mathematical side, I show how degeneracies buried deep within the theory render it mathematically ill-defined, while on the epistemological side, I prove that the postulates of IIT are scientifically unfalsifiable and inherently metaphysical. Given that IIT is the preeminent theory of consciousness in modern neuroscience, these results have far-reaching implications in this field. In addition, I show that the epistemic issues of falsifiability that hamstring IIT apply quite generally to all contemporary theories of consciousness, which suggests a major reframing of the problem is necessary. The problems that I reveal in regard to defining consciousness offer an important parallel in regard to defining life, as both fields seek to define their topic of study in absence of an existing theoretical framework. To avoid metaphysical problems related to falsifiability, universal theories of both life and consciousness must be framed with respect to independent empirical observations that can be used to benchmark predictions from the theory. In this regard, I argue that the epistemic debate over scientific theories of consciousness should be used to inform the discussion regarding theoretical definitions of life. (shrink)

Most cosmologists say dark matter must exist. So far, it’s nowhere to be found. A widely scorned rival theory explains why.

I discuss the relevance of the current predicament in cosmology to the debate over scientific realism. I argue that the existence of two, empirically successful but ontologically inconsistent cosmological theories presents difficulties for the realist position.

In Logik der Forschung (1934) and later works, Karl Popper proposed a set of methodological rules for scientists. Among these were requirements that theories should evolve in the direction of increasing content, and that new theories should only be accepted if some of their novel predictions are experimentally confirmed. There are currently two, viable theories of cosmology: the standard cosmological model, and a theory due to Mordehai Milgrom called MOND. Both theories can point to successes and failures, but only MOND (...) has repeatedly made novel predictions that were subsequently found to be correct. Standard-model cosmologists, by contrast, have almost always responded to new observations in a post-hoc manner, adjusting or augmenting their theory as needed to obtain correspondence with the facts. I argue that these methodological differences render a comparison of the two theories in terms of their ‘truthlikeness’ or ‘verisimilitude’ essentially impossible since the two groups of scientists achieve correspondence with the facts in fundamentally different ways, and I suggest that a better guide to the theories’ progress toward the truth might be the methodologies themselves. (shrink)

This essay deals with Girolamo Fracastoro’s ensouled cosmology. His Homocentrica sive de stellis (1538), an astronomy of concentric spheres, was discussed by the Padua School of Aristotelians. Since the polemics over the immortality of the human soul, which had famously opposed Pomponazzi to Nifo, psychological discussions—including those about heavenly spheres’ souls—raised heated controversies. Fracastoro discussed the foundations of his homocentric planetary theory in a dialogue titled Fracastorius, sive de anima (1555). In a 1531 exchange with Gasparo Contarini, Fracastoro discussed celestial (...) physics, including problems linked to mathematical analysis of physical causation. Contarini expressed his doubts over Fracastoro’s lack of consideration of Aristotelian viewpoints on heavenly souls and intelligences. Fracastoro offered an account of cosmic animation in his later dialogue “On the Soul,” taking a different path than his Paduan teachers. He picked up the Platonic idea of the “world soul,” freely connecting it with Aristotelian views about the ensouled cosmos of concentric spheres, resulting in an eclectic composition of Platonic, Aristotelian, and Averroistic elements. Fracastoro grounded his renewed mathematical astronomy on an understanding of the cosmos as a living whole. His animated homocentric cosmos represented a development of Aristotelian premises and a step beyond this legacy. (shrink)

James Redford, The Physics of God and the Quantum Gravity Theory of Everything: And Other Selected Works (Chișinău, Moldova: Eliva Press, 2021), 268 pp., ISBN-10: 1636482775, ISBN-13: 9781636482774.