Black holes entered scientific literature as early as at the end of eighteenth century. They had been known at that time as dark stars, but their concept did not find its way to physics or astronomy, and had been abandoned for more than one hundred years. I shall sketch historical developments and discuss present mathematical and observational status of black holes.

On the 10th of April, 2019 the Event Horizon Telescope Collaboration presented the first image of the black hole. The image was obtained with a planet-scale array of eight ground-based radio telescopes. The observation relied on a technique called very long base interferometry which synchronises telescope facilities around the world. The image of a black hole together with the recent detections of gravitational waves confirms one of the most intriguing predictions of Einstein’s gravity theory, namely, the existence (...) of black holes. I will provide more details on this remarkable observation and explore its consequences for our understanding of nature. The physical reality of black holes is strongly supported by recent advances of astronomy. I claim that this fact is the key to understanding the relation between our world and the world of mathematics. (shrink)

The Schwarzschild solution has played a fundamental conceptual role in general relativity, and beyond, for instance, regarding event horizons, spacetime singularities and aspects of quantum field theory in curved spacetimes. However, one still encounters the existence of misconceptions and a certain ambiguity inherent in the Schwarzschild solution in the literature. By taking into account the point of view of an observer in the interior of the event horizon, one verifies that new conceptual difficulties arise. In this work, besides providing a (...) very brief pedagogical review, we further analyze the interior Schwarzschild black hole solution. Firstly, by deducing the interior metric by considering time-dependent metric coefficients, the interior region is analyzed without the prejudices inherited from the exterior geometry. We also pay close attention to several respective cosmological interpretations, and briefly address some of the difficulties associated to spacetime singularities. Secondly, we deduce the conserved quantities of null and timelike geodesics, and discuss several particular cases in some detail. Thirdly, we examine the Eddington–Finkelstein and Kruskal coordinates directly from the interior solution. In concluding, it is important to emphasize that the interior structure of realistic black holes has not been satisfactorily determined, and is still open to considerable debate. (shrink)

In this paper a simple (i.e. free of fine-tuning, etc.) new mechanism for primordial black hole formation based on the collapse of large antimatter systems in the early Universe is introduced. A peculiarity of this process is that, compared to their material counterparts, the collapse of large antimatter systems takes much less time due to the reversed thermodynamics of antimatter, an idea which has been proposed in our earlier paper Etesi (2021). This model has several testable predictions. The (...) class='Hi'>first is that the photon-baryon ratio is roughly computable and is equal to \(3.03\times 10^9\) which is quite close to its experimentally confirmed value. The second is that the mass of black holes arising from this mechanism is at least \(10^5\) - \(10^6M_\odot\) hence they contribute to the super- or hypermassive end of the primordial black hole mass spectrum. The third prediction is that these sort of primordial black holes constitute at least \(20\%\) of dark matter. Last but not least the observed current asymmetry of matter and antimatter, even if their presence in the Universe was symmetric in the beginning, acquires a natural explanation, too. (shrink)

We review the gravitational self-force program to analytically compute first-order metric perturbations in a Schwarzschild black hole spacetime in the case of a perturbing mass moving on a slightly eccentric equatorial orbit. The perturbed metric components should then be combined into gauge-invariant quantities to be associated with physical observables. In this way, for example, one determines the various “potentials” entering the Effective-One-Body model, i.e., a powerful formalism for the description of the gravitational interaction of two masses, which is (...) currently successfully used for the analysis of gravitational wave signals. (shrink)

As a leading member of the Vienna Circle, Rudolph Carnap's aim was to bring about a "unified science" by applying a method of logical analysis to the empirical data of all the sciences. This work, first published in English in 1934, endeavors to work out a way in which the observation statements required for verification are not private to the observer. The work shows the strong influence of Wittgenstein, Russell, and Frege.

The compact and, with \ M\, very massive object located at the center of the Milky Way is currently the very best candidate for a supermassive black hole in our immediate vicinity. The strongest evidence for this is provided by measurements of stellar orbits, variable X-ray emission, and strongly variable polarized near-infrared emission from the location of the radio source Sagittarius A* in the middle of the central stellar cluster. Simultaneous near-infrared and X-ray observations of SgrA* have revealed (...) insights into the emission mechanisms responsible for the powerful near-infrared and X-ray flares from within a few tens to one hundred Schwarzschild radii of such a putative SMBH. If SgrA* is indeed a SMBH it will, in projection onto the sky, have the largest event horizon and will certainly be the first and most important target for very long baseline interferometry observations currently being prepared by the event horizon telescope. These observations in combination with the infrared interferometry experiment GRAVITY at the very large telescope interferometer and other experiments across the electromagnetic spectrum might yield proof for the presence of a black hole at the center of the Milky Way. The large body of evidence continues to discriminate the identification of SgrA* as a SMBH from alternative possibilities. It is, however, unclear when the ever mounting evidence for SgrA* being associated with a SMBH will suffice as a convincing proof. Additional compelling evidence may come from future gravitational wave observatories. This manuscript reviews the observational facts, theoretical grounds and conceptual aspects for the case of SgrA* being a black hole. We treat theory and observations in the framework of the philosophical discussions about “realism and underdetermination”, as this line of arguments allows us to describe the situation in observational astrophysics with respect to supermassive black holes. Questions concerning the existence of supermassive black holes and in particular SgrA* are discussed using causation as an indispensable element. We show that the results of our investigation are convincingly mapped out by this combination of concepts. (shrink)

A productive way to think about imagistic mental models of physical systems is as though they were sources of quasi‐empirical evidence. People depict or imagine events at those points in time when they would experiment with the world if possible. Moreover, just as they would do when observing the world, people induce patterns of behavior from the results depicted in their imaginations. These resulting patterns of behavior can then be cast into symbolic rules to simplify thinking about future problems and (...) to reveal higher order relationships. Using simple gear problems, three experiments explored the occasions of use for, and the inductive transitions between, depictive models and number‐based rules. The first two experiments used the convergent evidence of problem‐solving latencies, hand motions, referential language and error data to document the initial use of a model, the induction of rules from the modeling results, and the fallback to a model when a rule fails. The third experiment explored the intermediate representations that facilitate the induction of rules from depictive models. The strengths and weaknesses of depictive modeling and more analytic systems of reasoning are delineated to motivate the reasons for these transitions. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:The Dharma of Justice in the Sanskrit Epics: Debates on Gender, Varna, and Species by Ruth VanitaBrian Black (bio)The Dharma of Justice in the Sanskrit Epics: Debates on Gender, Varna, and Species. By Ruth Vanita. Oxford: Oxford Unity Press, 2021. Pp. 298. Hardcover £70.00, isbn 978-0-19-285982-2. Ruth Vanita's The Dharma of Justice in the Sanskrit Epics: Debates on Gender, Varna, and Species examines how the Mahābhārata and (...) Rāmāyaṇa discuss questions of justice. She reads the epics as bhakti texts to focus on their depictions of discrimination based on social categories such as gender, varṇa, species, age, and disability. The book claims that the epics criticize oppression in two main ways: by articulating philosophical ideas about social justice and by celebrating characters of a low social status. Six of the twelve chapters are devoted to themes related to gender, including marriage, independence, consent, gender-crossing, parenting, and masculinity. Focusing on the words and actions of characters in the narrative, Vanita does not directly address the question of whether we can take the marginal voices in the text as representing authentic voices of its social context. She also sidesteps the issue of patriarchy: "Every written text ever composed is, in the widest sense, patriarchal, since it was composed in a male-dominated society. Patriarchy is the air we breathe. Therefore, explaining the meaning of a text as patriarchal is as useful as explaining people's actions by the fact that they breathe" (p. 22). I was left wondering, however, if this explanation serves the interests of her study. In a book about oppressed characters, it seems crucial to say more about how systems of oppression operate. Even if we assume that all societies are patriarchal, this does not mean that they are all patriarchal in the same ways or to the same degree. Vanita is an imaginative reader, whose often speculative interpretations offer some valuable perspectives and raise interesting questions. One of the most refreshing features of the book is its extensive discussions of a number of characters and sub-stories rarely analyzed in scholarly literature. In particular, I enjoyed reading Vanita's take on the Mahābhārata's story of Diśā and Aṣṭāvakra (Mbh 13.19–22), where she shows her sensitivity to the ambiguities of this intriguing episode. This story, which appears in the Anuśāsana Parvan, begins when the ascetic Aṣṭāvakra wants to marry the sage Vadānya's daughter, Suprabhā. Before offering his consent, Vadānya sends Aṣṭāvakra to visit the aged female sage Diśā. As Vanita observes, this episode "maps a landscape of desire" [End Page 1] (p. 77) and raises a number of interesting questions about female sexuality as well as female independence. Vanita sees Diśā's motives, rather than merely testing Aṣṭāvakra's desires, as combining her role as a teacher with her own sexual yearnings. Vanita concludes that Diśā's message is that "desire cannot be entirely overcome" (p. 82). From this, she sees Diśā as advocating the conversion of "feverish agitation into happiness within marriage" (p. 83). Vanita's analysis of this story is both engaging and compelling, yet her claim that this episode is an integral part of Yudhiṣṭhira's education as a king remains undeveloped. I wanted to hear more about how this one story fits into the context of the countless others that Bhīṣma recounts to Yudhiṣṭhira. Moreover, her conclusion at the end of the chapter (ch. 4), that the epics "celebrate single women" (p. 85), seems a bit of a stretch considering the few examples she discusses. In chapter 6, Vanita revisits the encounter between Sulabhā and King Janaka (Mbh 12.308), which she discussed in detail twenty years ago.1 Her return to this episode examines the sexual power dynamics between the female sage and the legendary king from Upaniṣadic lore. As Vanita observes, Sulabhā takes the form of a beautiful young woman to test Janaka's claim to be liberated. Vanita explains:We may expect ordinary people to notice a person's looks first of all, but one who claims to be... (shrink)

Presentations of black hole complementarity by van Dongen and de Haro, as well as by 't Hooft, suffer from a mistaken claim that interactions between matter falling into a black hole and the emitted Hawking-like radiation should lead to a failure of commutativity between space-like-related observables localized inside and outside the black hole. I show that this conclusion is not supported by our standard understanding of quantum interactions. We have no reason to believe that near-horizon interactions will (...) threaten microcausality. If these interactions reliably transfer information to the outgoing radiation, then this response to Hawking's information loss argument should amount to a version of the bleaching scenario. I argue that the challenge facing black hole complementarity is that of reconciling this commitment to bleaching with the expectation that the event horizon will be locally unremarkable. This challenge is most promisingly met by proposals that postulate a consistent account of the limitations of our local semi-classical theories, but no support is added to these postulates by appeals to verificationism or to the interactions considered by 't Hooft. (shrink)

This paper will discuss the recent LIGO-Virgo observations of gravitational waves and the binary black hole mergers that produce them. These observations rely on having prior knowledge of the dynamical behaviour of binary black hole systems, as governed by the Einstein Field Equations (EFEs). However, we currently lack any exact, analytic solutions to the EFEs describing such systems. In the absence of such solutions, a range of modelling approaches are used to mediate between the dynamical equations (...) and the experimental data. Models based on post-Newtonian approximation, the effective one-body formalism, and numerical relativity simulations (and combinations of these) bridge the gap between theory and observations and make the LIGO-Virgo experiments possible. In particular, this paper will consider how such models are validated as accurate descriptions of real-world binary black hole mergers (and the resulting gravitational waves) in the face of an epistemic circularity problem: the validity of these models must be assumed to justify claims about gravitational wave sources, but this validity can only be established based on these same observations. (shrink)

The concept of black holes or completely collapsed gravitational objects as they were originally called has fascinated the scientific community and writers of science fiction for centuries. The mathematical proof of the existence of black holes came from the collation of multiple lines of evidence, some of which were highly debated and was derived from both indirect and direct sources. The measurement of gravitational waves and the observation of a black hole represent one of the (...) most astounding achievements in astrophysics which will open up new areas of investigation for the role that black holes play in the formation, maintenance and evolution of galactic structure. (shrink)

What, if anything, is wrong with conspiracy theories? A conspiracy refers to a group of people acting in secret to achieve some nefarious goal. But given that the pages of history are full of such plots, why are CTs regarded with suspicion? Just like with the traditional demarcation problem, philosophers disagree about where to draw the line between legitimate hypotheses about conspiracies and unfounded ‘conspiracy theories’. Some believe that there is no such demarcation line to be drawn, that each CT (...) should be evaluated on its own merits, and that the bad reputation of CTs is wholly undeserved. In this paper, I intend to rescue the intuition that there is indeed something prima facie suspicious about CTs. First, I demarcate legitimate theorizing about real-life conspiracies from “mere conspiracy theories”. Along the way, my analysis will clarify some epistemological issues surrounding falsifiability, asymmetries between causes and effects, and hypotheses involving intentional agents. Because of their extreme resilience to external criticism and counterevidence, I argue, CTs are the epistemological equivalent of a ‘black hole’, in which unwary truth-seekers are drawn, never to escape again. But this strong attraction of CTs comes at a steep price: their theoretical parameters are essentially arbitrary, making them vulnerable to internal disruption. In essence, because it is so easy to construct a novel CT, it is equally easy to construct many ones about the same historical event. And that is what justifies our suspicion of CTs. (shrink)

Black hole thermodynamics is regarded as one of the deepest clues we have to a quantum theory of gravity. It motivates scores of proposals in the field, from the thought that the world is a hologram to calculations in string theory. The rationale for BHT playing this important role, and for much of BHT itself, originates in the analogy between black hole behavior and ordinary thermodynamic systems. Claiming the relationship is “more than a formal analogy,” black (...) class='Hi'>holes are said to be governed by deep thermodynamic principles: what causes your tea to come to room temperature is said additionally to cause the area of black holes to increase. Playing the role of philosophical gadfly, we pour a little cold water on the claim that BHT is more than a formal analogy. First, we show that BHT is often based on a kind of caricature of thermodynamics. Second, we point out an important ambiguity in what systems the analogy is supposed to govern, local or global ones. Finally, and perhaps worst, we point out that one of the primary motivations for the theory arises from a terribly controversial understanding of entropy. BHT may be a useful guide to future physics. Only time will tell. But the analogy is not nearly as good as is commonly supposed. (shrink)

This essay examines how Michel Henry's and Jean‐Luc Marion's continuation of phenomenology's turn to the invisible relates to painting, aesthetics, and theology. First, it discusses Henry and Marion's redefinition of phenomenality. Second, it explores Henry's “Kandinskian” description of abstract painting as expressing “Life.” Third, it explicates Marion's “Rothkoian” rehabilitation of the idol and renewed zeal for the icon—both phenomena exemplify “givenness.” Fourth, it unpacks my thesis: Henry's phenomenology, theologically applied, exercises an inadequate Kantian apophasis, characterized by a sublime sacrifice (...) of the imagination; although Marion's work sometimes evidences a similar tendency, its prevailing momentum offers theology a fully catholic scope. (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. (shrink)

I distinguish between two versions of the black hole information-loss paradox. The first arises from apparent failure of unitarity on the spacetime of a completely evaporating black hole, which appears to be non-globally-hyperbolic; this is the most commonly discussed version of the paradox in the foundational and semipopular literature, and the case for calling it `paradoxical' is less than compelling. But the second arises from a clash between a fully-statistical-mechanical interpretation of black hole evaporation and the (...) quantum-field-theoretic description used in derivations of the Hawking effect. This version of the paradox arises long before a black hole completely evaporates, seems to be the version that has played a central role in quantum gravity, and is genuinely paradoxical. After explicating the paradox, I discuss the implications of more recent work on AdS/CFT duality and on the `Firewall paradox', and conclude that the paradox is if anything now sharper. The article is written at a introductory level and does not assume advanced knowledge of quantum gravity. (shrink)

Stationary spacetimes containing a black hole have several properties akin to those of atoms. For instance, such spacetimes have only three classical degrees of freedom, or observables, which may be taken to be the mass, the angular momentum, and the electric charge of the hole. There are several arguments supporting a proposal originally made by Bekenstein that quantization of these classical degrees of freedom gives an equal spacing for the horizon area spectrum of black holes. We review (...) some of these arguments and introduce a specific Hamiltonian quantum theory of black holes. Our Hamiltonian quantum theory gives, among other things, a discrete spectrum for the classical observables, and it produces an area spectrum which is closely related to Bekenstein's proposal. We also present a foamlike model of horizons of spacetime. In our model spacetime horizon consists of microscopic Schwarzschild black holes. Applying our Hamiltonian approach to this model we find that the entropy of any horizon is one quarter of its area. (shrink)

A Brief History of Time: From the Big Bang to Black Holes is a popular-science book on cosmology (the study of the origin and evolution of the universe) by British physicist Stephen Hawking. It was first published in 1988. Hawking wrote the book for readers who have no prior knowledge of the universe and people who are interested in learning.

High throughput time-resolved observations of accreting collapsed objects at X-ray energies provide key information on the motions of matter orbiting a few gravitational radii away from black holes. Predictions of general relativity in the strong field regime, such as relativistic epicyclic motions, precession, light bending and the presence and radius of an innermost stable circular orbit in the close vicinity of a black hole can be verified by making use of two powerful diagnostics, namely relativistically broadened (...) \ lines and variability on dynamical timescales, quasi periodic oscillations in particular. Moreover tomography and reverberation techniques relying upon combined spectral timing and polarimetric timing provide an entirely new perspective in the field. Both the low and high spacetime curvature regimes of gravity can be probed by studying black holes of vastly different masses in X-ray binaries and Active Galactic Nuclei, opening up the possibility of testing also some alternative theories of gravity. To achieve these goals, very large area X-ray instrumentation with good spectral resolution and polarimetric capability is required. Prospects and projects in this area of research are briefly surveyed. (shrink)

The relevance of gravitational boundary degrees of freedom and their dynamics in gravity quantization and black hole information has been explored in a series of recent works. In this work we further progress by focusing keenly on the genuine gravitational boundary degrees of freedom as the origin of black hole entropy. Wald’s entropy formula is scrutinized, and the reason that Wald’s formula correctly captures the entropy of a black hole examined. Afterwards, limitations of Wald’s method are discussed; (...) a coherent view of entropy based on boundary dynamics is presented. The discrepancy observed in the literature between holographic and Wald’s entropies is addressed. We generalize the entropy definition so as to handle a time-dependent black hole. Large gauge symmetry plays a pivotal role. Non-Dirichlet boundary conditions and gravitational analogues of Coleman-De Luccia bounce solutions are central in identifying the microstates and differentiating the origins of entropies associated with different classes of solutions. The result in the present work leads to a view that black hole entropy is entanglement entropy in a thermodynamic setup. (shrink)

Hawking particles emitted by a black hole are usually found to have thermal spectra, if not exactly, then by a very good approximation. Here, we argue differently. It was discovered that spherical partial waves of in-going and out-going matter can be described by unitary evolution operators independently, which allows for studies of space-time properties that were not possible before. Unitarity dictates space-time, as seen by a distant observer, to be topologically non-trivial. Consequently, Hawking particles are only locally thermal, but (...) globally not: we explain why Hawking particles emerging from one hemisphere of a black hole must be 100 % entangled with the Hawking particles emerging from the other hemisphere. This produces exclusively pure quantum states evolving in a unitary manner, and removes the interior region for the outside observer, while it still completely agrees locally with the laws of general relativity. Unitarity is a starting point; no other assumptions are made. Region I and the diametrically opposite region II of the Penrose diagram represent antipodal points in a PT or CPT relation, as was suggested before. On the horizon itself, antipodal points are identified. A candidate instanton is proposed to describe the formation and evaporation of virtual black holes of the type described here. (shrink)

We propose that black holes may serve as a physical substratum for intelligent beings, based on(1) The descriptions of brain and psyche are complementary to each other, as internal and external observers of a black hole in the Susskind-t'Hooft's schema.(2) There is an aspect of the inner structure of a black hole that is isomorphic to the structure of the human subjective domain in the psychological model of reflexion.(3) Both black holes and the brain-psyche (...) system have a facet that can be represented using thermodynamic concepts.(4) Both lend themselves to a holographic description. (shrink)

In this Article I argue that the emerging public/private nexus of surveillance involves the augmentation of state power and calls for new models of constitutional constraint. The key phenomenon is the role played by communications intermediaries in collecting the information that the state subsequently accesses. These intermediaries are not just powerful companies engaged in collecting and analyzing the information of users and the information they hold are not just business records. The key feature of these companies is that, through their (...) information practices and architecture, they mediate other relationships. I argue that this mediating function, and its underlying technological form, interacts with legal and social norms in ways that can lead to the erosion of constraints on state power. This Article maps two stories of erosion, rooted in two kinds of community displacement. The first involves the displacement of community participation in law enforcement and the emergence of “technological tattletales” where intermediaries cooperate with the state. Unlike citizen cooperation, this practice augments state power and undermines more traditional informal modes of constraint on state power. The second involves the displacement of national legal and political community. Communications intermediaries are often large multinational companies that operate in multiple jurisdictions and move their data to various datacenters across the world even as the individual data subject remains in one geographical location. Laws that treat nonresident aliens differently from residents and citizens can create “constitutional black holes” where the communications data of an individual is not protected by any constitutional constraints. (shrink)

Before the Apology trial by five hundred of his fellow Athenians, Socrates is put on trial by a close associate, Alcibiades, in the Symposium. The first trial prefigures or echoes the second, famous one. The speeches on love that precede the entrance of Alcibiades, especially Socrates's speech—in which he discloses instructions on love given to him by Diotima—is the basis on which Socrates should be judged. Because the jury for this trial does not render a verdict, I assume the (...) role of a juror. If I were a modern prospective juror, I might not pass voir dire; though, like Alcibiades, I have been a lover of Socrates, I have become disenchanted with him because I find no evidence that he examined his own life in the... (shrink)

Motivated by the known mathematical and physical problems arising from the current mathematical formalization of the physical spatio-temporal continuum, as a substantial technical clarification of our earlier attempt (Etesi in Found Sci 25:327–340, 2020), the aim in this paper is twofold. Firstly, by interpreting Chaitin’s variant of Gödel’s first incompleteness theorem as an inherent uncertainty or fuzziness present in the set of real numbers, a set-theoretic entropy is assigned to it using the Kullback–Leibler relative entropy of a pair of (...) Riemannian manifolds. Then exploiting the non-negativity of this relative entropy an abstract Hawking-like area theorem is derived. Secondly, by analyzing Noether’s theorem on symmetries and conserved quantities, we argue that whenever the four dimensional space-time continuum containing a single, stationary, asymptotically flat black hole is modeled by the set of real numbers in the mathematical formulation of general relativity, the hidden set-theoretic entropy of this latter structure reveals itself as the entropy of the black hole (proportional to the area of its “instantaneous” event horizon), indicating that this apparently physical quantity might have a pure set-theoretic origin, too. (shrink)

What is space? It isn't a question that most of us normally stop to ask. Space is the venue of physics; it's where things exist, where they move and take shape. Yet over the past few decades, physicists have discovered a phenomenon that operates outside the confines of space and time. The phenomenon-the ability of one particle to affect another instantly across the vastness of space-appears to be almost magical. Einstein grappled with this oddity and couldn't quite resolve it, describing (...) it as "spooky action at a distance." But this strange occurrence has direct connections to black holes, particle collisions, and even the workings of gravity. If space isn't what we thought it was, then what is it?In Spooky Action at a Distance, George Musser sets out to answer that question, offering a provocative exploration of nonlocality and a celebration of the scientists who are trying to understand it. Musser guides us on an epic journey of scientific discovery into the lives of experimental physicists observing particles acting in tandem, astronomers discovering galaxies that look statistically identical, and cosmologists hoping to unravel the paradoxes surrounding the big bang. Their conclusions challenge our understanding not only of space and time but of the origins of the universe-and their insights are spurring profound technological innovation and suggesting a new grand unified theory of physics. (shrink)

Non-perturbative quantum gravity prevents the formation of curvature singularities and may allow black holes to decay with a lifetime shorter than evaporation time. This, in connection with the existence of primordial black holes, could open a new window for quantum-gravity phenomenology. I discuss the possibility of observing astrophysical emissions from the explosion of old black holes in the radio and in the gamma wavelengths. These emissions can be discriminated from other astrophysical sources because of (...) a peculiar way the emitted wavelength scales with the distance. The spectrum of the diffuse radiation produced by those objects presents a peculiar distortion due to this scaling. (shrink)

This paper explores the prospects of radical hope for addressing the devastation of the Covid-19 pandemic. Hope is useful for conceptualizing the proper balance between too much fear and too little about our uncertain future. First, I describe the ethical challenge of the pandemic as a wicked problem. Because accepted ethical theories fail to motivate solutions, wicked problems pressure us to develop our value systems, exercise moral imaginations, and discover creative solutions. Second, I develop an Aristotelian account of radical (...) hope, drawing from ancient philosophy, virtue ethics, and recent climate ethics. Radical hope is a novel form of courage, which balances the goal of external success, that something good will emerge from the tragedy, against the goal of living well for its own sake through practical wisdom. I conclude by applying some lessons to our present situation. (shrink)

This paper discusses some philosophical aspects related to the recent publication of the experimental results of the 2017 black hole experiment, namely the first image of the supermassive black hole at the center of galaxy M87. In this paper I present a philosophical analysis of the 2017 Event Horizon Telescope (EHT) black hole experiment. I first present Hacking’s philosophy of experimentation. Hacking gives his taxonomy of elements of laboratory science and distinguishes a list of elements. (...) I show that the EHT experiment conforms to major elements from Hacking’s list. I then describe with the help of Galison’s Philosophy of the Shadow how the EHT Collaboration created the famous black hole image. Galison outlines three stages for the reconstruction of the black hole image: Socio-Epistemology, Mechanical Objectivity, after which there is an additional SocioEpistemology stage. I subsequently present my own interpretation of the reconstruction of the black hole image and I discuss model fitting to data. I suggest that the main method used by the EHT Collaboration to assure trust in the results of the EHT experiment is what philosophers call the Argument from Coincidence. I show that using this method for the above purpose is problematic. I present two versions of the Argument from Coincidence: Hacking’s Coincidence and Cartwright’s Reproducibility by which I analyse the EHT experiment. The same estimation of the mass of the black hole is reproduced in four different procedures. The EHT Collaboration concludes: the value we have converged upon is robust. I analyse the mass measurements of the black hole with the help of Cartwright’s notion of robustness. I show that the EHT Collaboration construe Coincidence/Reproducibility as Technological Agnosticism and I contrast this interpretation with van Fraassen’s scientific agnosticism. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Virtue Ethics for the Real World: Improving Character without Idealization by Howard J. CurzerBenjamin HoleCURZER, Howard J. Virtue Ethics for the Real World: Improving Character without Idealization. New York: Routledge, 2023. 272 pp. Cloth, $160.00The development of virtue ethics has been in a lull. This book is a welcome treatise in theory-building, developing a novel Aristotelian approach to virtue ethics that, first, avoids idealization and, second, provides (...) a method for character improvement. It is divided into two parts reflecting these themes.The front matter before the title page brandishes a "No Don Quixotes" sign, warning the reader the following pages are no place for a misguided idealist. Part 1, "Against Idealization," contains six chapters. Chapter 2 argues that idealization is not a useful guide, but an impediment to virtue, since ideals can be misleading, psychologically damaging, and used for nefarious purposes. Chapters 3 through 7 construct a virtue ethical theory without idealization. Idealization may seem central to a virtue-oriented approach to ethics. For example, Rosalind Hursthouse's famous biconditional claims that an act is right if and only if it is what the virtuous person would characteristically do in the same circumstances. By contrast, chapter 3 provides counterexamples separating virtuous action from what the virtuous person would characteristically do, and separating virtuous action from right action. Sacrificing Hursthouse's biconditional is a fundamental change to the way many conceive of Aristotelian virtue ethics, demanding revisions to the rest of the theory. For instance, to address moral dilemmas, chapter 4 defends two psychological mechanisms under which there are virtuous, morally wrong acts that are admirably immoral, and vicious, morally right acts that leave the agent with dirty hands.Chapter 5 provides the grounding for contemporary Aristotelian virtue ethics without idealization, by answering what makes character traits [End Page 541] virtues and what makes acts virtuous. Two-level eudaimonism involves a thin theory, where virtue consists in responding well to different spheres of human activity, and a thick theory, where responding well contributes to the agent's eudaimonia. Since virtuous people may characteristically perform nonvirtuous actions, virtuous actions are not necessarily what virtuous people characteristically do but actions that are endorsed by virtuous people from the perspective of virtue. The "Perspectives Doctrine" claims that virtuous people decide how to respond from the perspective of different virtues, and those perspectives offer incomplete and sometimes incompatible ways of responding. For instance, a temperate person endorsing an action as temperate from the perspective of temperance makes it temperate, but would not make it courageous, and an endorsement from the perspective of courage would not make her action temperate. Agents determine what is virtuous by asking virtuous people to consider, from the perspective of virtue, what should be done; when virtuous people are unavailable, agents can consult philosophers and social scientists who research the responses of virtuous people. Chapter 6 rejects the "Reciprocity of the Virtue Doctrine," which claims possessing one virtue entails possessing the rest, in favor of the "Unevenly Virtuous People Doctrine," on which people can have some but not all of the virtues; character typically improves at different paces in different areas of life. Chapter 7 rejects Philippa Foot's "Corrective Doctrine" of virtue as implausible idealization in favor of a traditionally Aristotelian "Doctrine of the Mean," and argues that the virtues of integrity, forgiveness, tolerance, open-mindedness, and civility are governed by that doctrine.Although character improvement seems to depend on idealization, by striving to achieve some end, part 2's five chapters paint an alternative picture. Chapter 8 defends a medical analogy over competing models philosophers typically employ to understand character improvement, including skill (Aristotle and Julia Annas), stage or path (Aristotle and Wouter Sanderse), self-cultivation (Mengzi), and self-construction (Xunzi) analogies. To improve character, one must look to a fine-grained list of possible character flaws, diagnose deficits in character, and then heal character flaws by employing targeted strategies, including "inculcation strategies, rehabilitation strategies, and strategies to improve society's ethical climate." Character improvement is complex and becomes more so when considering all of the ways one might err. Chapter 9 introduces an Aristotelian model for moral decision-making within each... (shrink)

An extended scale relativity theory, actively developed by one of the authors, incorporates Nottale's scale relativity principle where the Planck scale is the minimum impassible invariant scale in Nature, and the use of polyvector-valued coordinates in C-spaces (Clifford manifolds) where all lengths, areas, volumes⋅ are treated on equal footing. We study the generalization of the ordinary point-particle quantum mechanical oscillator to the p-loop (a closed p-brane) case in C-spaces. Its solution exhibits some novel features: an emergence of two explicit scales (...) delineating the asymptotic regimes (Planck scale region and a smooth region of a quantum point oscillator). In the most interesting Planck scale regime, the solution recovers in an elementary fashion some basic relations of string theory (including string tension quantization and string uncertainty relation). It is shown that the degeneracy of the first collective excited state of the p-loop oscillator yields not only the well-known Bekenstein–Hawking area-entropy linear relation but also the logarithmic corrections therein. In addition we obtain for any number of dimensions the Hawking temperature, the Schwarschild radius, and the inequalities governing the area of a black hole formed in a fusion of two black holes. One of the interesting results is a demonstration that the evaporation of a black hole is limited by the upper bound on its temperature, the Planck temperature. (shrink)

Consider a contemporary retrieval of Aristotle’s account of moral perception. Drawing from EN.VI.8, Martha Nussbaum argues that we perceive moral particulars prior to ethical principles. First, I explain her priority of the particular thesis. The virtuous person perceives value in the world, as part of her moral deliberation. This perceptual skill is an important aspect of her virtuous activity, and hence also part of her eudaimonia. Second, I present her priority thesis with a dilemma: our perception of moral particulars (...) is either non-inferential or it is inferential. If Nussbaum accepts a non-inferential interpretation, then she is committed to an unsavory view about moral epistemology –one that invites intuitionism and relativism. But if she accepts a non-inferential account, then the moral particular is no longer prior to the ethical principle. I suggest that her better option is to grab the second horn. This move avoids the problems of the first horn without sacrificing her neo-Aristotelian commitments or her overarching view that the perception of moral particulars is ineliminable to moral deliberation. At the same time, this move renders her priority thesis trivial. (shrink)

Insights from First Amendment considerations and from developmental psychology are utilized in suggesting that whatever value codes of ethics may hold for the mass media, they represent serious difficulties in inculcating substantial ethical values in individual journalists and in the profession as a whole. Evidence from developmental psychology suggests that codes are probably of some limited value to the neophyte working in the media. Codes also help assure non?journalists that the industry really is concerned about ethics. However, codes probably (...) should be relegated to a framed wall hanging for any journalists who have advanced beyond their internships. Confusion reigns because codes are often founded on moralistic rather than moral?philosophical bases, and there is a blurring between general precepts and specific practices covered in codes. As individual professionals mature intellectually and ethically, they should transcend socially?approved conventions codified by ?regulators,?; and begin to become social catalysts in their own rights, according to this essay. (shrink)

Real business cycle theory, as exemplified by Fischer Black's Business Cycles and Equilibrium, posits that business cycles are due to random?technology shocks,? and not to monetary, fiscal or other government policies. Rational expectations and complete markets are supposed to enable decision makers to avoid the costly mistakes that would otherwise result from policies that distort incentives to borrow and invest. This paper questions the assumptions of rational expectations and complete markets from an Austrian?school perspective. It argues that decision makers (...) economize on information costs by basing their plans at least in part on the actual prices observed in the course of doing business, and that government regulations have impinged on the evolution of markets, leaving them far from complete. (shrink)

Continuity as appears to us immediately by intuition differs from its current formalization, the arithmetical continuum or equivalently the set of real numbers used in modern mathematical analysis. Motivated by the known mathematical and physical problems arising from this formalization of the continuum, our aim in this paper is twofold. Firstly, by interpreting Chaitin’s variant of Gödel’s first incompleteness theorem as an inherent uncertainty or fuzziness of the arithmetical continuum, a formal set-theoretic entropy is assigned to the arithmetical continuum. (...) Secondly, by analyzing Noether’s theorem on symmetries and conserved quantities, we argue that whenever the four dimensional space-time continuum containing a single, stationary, asymptotically flat black hole is modeled by the arithmetical continuum in the mathematical formulation of general relativity, the hidden set-theoretic entropy of this latter structure reveals itself as the entropy of the black hole, indicating that this apparently physical quantity might have a pure set-theoretic origin, too. (shrink)

Professor Bernstein’s paper raises enough issues for a dozen commentaries. This is my first difficulty, for I can give at most one. Nevertheless, I regard the fact that the paper does raise all these many issues a very great virtue of it. The thinking which it provokes is very rewarding. I have learned a great deal from it.

Out of many years of work with children and youth, Algernon D. Black, a Leader of the American Ethical Culture Movement, and Head of the Ethics Department of the Ethical Culture Schools, has written this simple and lucid book to help young  ...

Covid-19 presents itself as a strange catastrophe. It has neither destroyed the planet nor has it erased humanity… but it has, in many ways, served to upend and alter what was previously considered ‘normal.’ As a result, what is perhaps the most notable characteristic of the Covid catastrophe is the very way it endures. Beyond any notion of catastrophic shock, the Covid catastrophe continues, indeed, it lingers in daily news cycles, changes to working environments and restrictions on travel. It is (...) an enduring presence, from which any determination of its ‘end’ is either nullified by an unending stream of Covid reports, or worse, ignored altogether. On this basis alone, is it even possible to discern an ‘end’ to Covid? (shrink)

Plastic changes in spinal cord function like neuronal wind-up and increased receptive field are too short-lived to explain chronic pain without structural changes. It is possible that learning could be a mechanism for longlasting changes in nociceptive regulation. A learning process localized to the spinal cord has been shown to be important for the development of tolerance to the analgetic effect of ethanol, suggesting that nociceptive control systems may be changed by learning. Long term potentiation (LTP) is regarded as a (...) useful model of learning and memory. LTP-like changes have been observed in invitro preparations from the spinal cord and in spinal cord field potentials. Recently a long term increase in spinal A-[beta] and C-fibre evoked responses after painful stimulation has been observed. [coderre & katz, dickenson, wiesenfeld-hallin et al.]. (shrink)

Kin relations have a strong theoretical and empirical basis for explaining cooperative behavior. Nevertheless, there is growing recognition that context—the cooperative environment of an individual—also shapes the willingness of individuals to cooperate. For nomadic pastoralists in Norway, cooperation among both kin and non-kin is an essential predictor for success. The northern parts of the country are characterized by a history of herder-herder competition exacerbating between-herder conflict, lack of trust, and subsequent coordination problems. In contrast, because of a history of herder-farmer (...) competition, southern Norway is characterized by high levels of between-herder coordination and trust. This comparative study investigates the relative importance of “cooperative context” and kinship in structuring cooperative behavior using an experimental gift game. The main findings from this study were that in the South, a high level of cooperation around an individual pushes gifts to be distributed evenly among other herders. Nevertheless, kinship matters, since close kin give and receive larger gifts. In contrast, kinship seems to be the main factor affecting gift distribution in the North. Herders in the North are also concerned with distributing gifts equally, albeit limiting them to close kin: the level of intragroup cooperation drives gifts to be distributed evenly among other closely related herders. The observed regional contrasts in cooperative decisions fit with the different historical levels of conflict and trust in the two regions: whereas herders in the South are affected by both cooperative context and kinship, kinship seems to be the main determinant of cooperation in the North. (shrink)

In 2021, the men’s English national football team reached their first final at a major international tournament since winning the World Cup in 1966. This success followed their previous achievement of reaching the semi-finals (knocked-out by Croatia) at the 2018 World Cup. True to form, the defeats proved unfalteringly English; with the 2021 final echoing previous tournament defeats, as England lost to Italy on penalties. However, what resonated with the predictability of an English defeat, was the accompanying chant, ‘it’s (...) coming home’. A ubiquitous presence throughout the course of both tournaments—while chanted at England football matches, it was also repeated across social media, the press and commercial advertising—the chant originates from the 1996 single, Three Lions (Football’s Coming Home), performed by David Baddiel, Frank Skinner and The Lightning Seeds. In what follows critical attention will be given to examining how the song offers what will be argued is a melancholic outlook. By re-approaching examples of English nostalgia and hubris, this chapter will expose how illustrations of English melancholy offer the potential for promoting collective forms of expression, which, when contextualized alongside England’s lack of footballing success (for the men’s team, at least), can be offset against a melancholic mediation that is cognizant of the centrality of loss—both for the subject and our collective sporting endeavours. (shrink)

We evaluate the “story grammar” approach to story understanding from three perspectives. We first examine the formal properties of the grammars and find only one to be formally adequate. We next evaluate the grammars empirically by asking whether they generate all simple stories and whether they generate only stories. We find many stories that they do not generate and one major class of nonstory that they do generate. We also evaluate the grammars' potential as comprehension models and find that (...) they would add nothing to semantic models that focus on the story content. Hence we advocate a story content oriented approach to studying story understanding instead of the structural story grammar approach. (shrink)

KJORVEN M, RUSH K and HOLE R. Nursing Inquiry 2011; 18: 325–335 A discursive exploration of the practices that shape and discipline nurses’ responses to postoperative deliriumAlthough delirium is classified as a medical emergency, it is often not treated as such by health care providers. The aim of this study was to critically examine, through a poststructural, Foucauldian concept of discourse, the language practices and discourses that shape and discipline nurses' care of older adults with postoperative delirium (POD) with a (...) purpose to question accepted nursing practice. The study was based on data collected from face‐to‐face, in‐depth, personal interviews with six nurses who work on an acute postoperative patient care unit. Five analytic readings of the data identified two prominent discourses at work in nursing practice which influenced the care of patients with POD. These were identified as discourses of legitimacy/illegitimacy and discourses of nursing work. Through the process of poststructural analysis it became evident that one overriding discourse – the biomedical/scientific discourse – served to direct, legitimize and govern all other discourses. The findings of this study have implications for nursing knowledge and practice, length of hospital stay and improved patient outcomes. This study builds on previous work and is the first study to conduct a discourse analysis illuminating nurses’ responses to POD through comparison with other acute medical emergencies from a poststructural perspective. (shrink)

The first part of this paper examines conditions in accord with Einstein's criterion of regularity on the field solutions everywhere that would correspond to the existence of a black hole star, following from solutions of his (nonvacuum) field equations. ‘Black hole’ is defined here as a star whose matter is so condensed as to correspond to a complete family of spatially closed geodesics. The condition imposed is that the angular momentum of a test body in each of (...) the closed geodesics is a constant of the motion. The second part of the paper examines the implications in the problem of the condensed star of a generalized (factorized) version of the metrical field equations, discovered earlier by the author. It is found that in general relativity stars should naturally pulsate, and in its succeeding cycles the gravitational radius of the star is attenuated by a factor exp(−0.349T), where T is the pulsation period. Conditions are discussed for the possibility that the (relatively) regular emissions of radiation from a pulsar may be dynamically rooted in a (smaller) part of the pulsation cycle when the star is out of the black hole state (less dense → open geodesics)—when radiation would be emitted to the outside world—and the (greater) part of the cycle when it is in the black hole state (more dense → closed geodesics)—when radiation would not be emitted. (shrink)

This essay aims to demonstrate how attention to black political thought might expand and complicate our understanding of modern politics and the conceptualization of the political in contemporary political theory, and in modern politics more generally. Black political thought can be viewed as the attempt to develop a set of critical tools to help explain the political distinctiveness of black life-worlds and how this distinctiveness is structured by a series of relations between individual and community, self and (...) other, state and society, citizen and non-citizen, and national and multinational (or global) circumstances. Too often, black politics is exclusively considered as a form of minority group politics and phenomena reducible to empirical investigation and observation, rather than a set of practices with underlying conceptual, theoretical, and epistemological premises. If we understand race as a fundamentally relational concept, namely, an assumption of dynamic interaction between two or more putatively distinct groups, and racism as a political phenomena that is conditioned and articulated through politics, then taken together they provide the opportunity for reflection and consideration of how black peoples and subjects have conceptualized, created and engaged in politics, political communities, and their articulation. Race and racism, the modalities of political participation and, conversely, the modalities of political exclusion have been recurrent themes in black political thought. The distinctiveness of black political thought is symptomatic of the distinctive trajectories of black politics, which first emerged from spaces of exclusion in Western polities and colonies. The histories of black political and social movements provide evidence of the ways in which black subordination in Western societies and polities required the reconfiguration of the actual boundaries between the public and private, the political and the social. Race and racism, the distinction between identity and identification, black solidarities, and the relationship between history, context, and politics and the political are themes central to black political thought. (shrink)

It is a paradox, whose importance familiarity fails to diminish, that the most highly developed and useful scientific theories are ostensibly expressed in terms of objects never encountered in experience. The line traced by a draughtsman, no matter how accurate, is seen beneath the microscope as a kind of corrugated trench, far removed from the ideal line of pure geometry. And the “point-planet” of astronomy, the “perfect gas” of thermodynamics, or the “pure species” of genetics are equally remote from exact (...) realization. Indeed the unintelligibility at the atomic or sub-atomic level of the notion of a rigidly demarcated boundary shows that such objects not merely are not but could not be encountered. While the mathematician constructs a theory in terms of “perfect” objects, the experimental scientist observes objects of which the properties demanded by theory are and can, in the very nature of measurement, be only approximately true. As Duhem remarks, mathematical deduction is not useful to the physicist if interpreted rigorously. It is necessary to know that its validity is unaltered when the premise and conclusion are only “approximately true.” But the indeterminacy thus introduced, it is necessary to add in criticism, will invalidate the deduction unless the permissible limits of variation are specified. To do so, however, replaces the original mathematical deduction by a more complicated mathematical theory in respect of whose interpretation the same problem arises, and whose exact nature is in any case unknown. (shrink)

It has long been a truism of the history of philosophy that intentionality is an invention of the medieval period, and within this standard narrative, the central place of Arabic philosophy has always been acknowledged. Yet there are many misconceptions surrounding the theories of intentionality advanced by the two main Arabic thinkers whose works were available to the West, Avicenna and Averroes. In the first part of this paper I offer an overview of the general accounts of intentionality and (...) intentional being found in the linguistic, psychological, and metaphysical writings of Avicenna and Averroes, and I trace the terminology of “intentions” to a neglected passage from Avicenna’s logic. In the second part of the paper I examine the way that Avicenna and Averroes apply their general theories of intentionality to the realm of sense perception. I offer an explanation of why Avicenna might have chosen to denominate the objects of the internal sense faculty of estimation as “intentions”, and I explore the implications of Averroes’s decision to attribute intentionality to the external senses and the media of perception. (shrink)

Research now provides participants greater indications of genetic risk for disease, even for conditions incidental to the research study. Given this development, should such information also be disclosed to the family of research participants? There has been some indication at the national level that genetic risk information can be disclosed to participants' families; however, limited attention has been given to returning research results to family. Thus, we have also incorporated the discussion surrounding the disclosure of genetic risk discovered in the (...) clinic (e.g., genetic testing). A number of important questions are examined: Should genetic research results be provided to family? Are there differences between clinical and research findings that would prevent research results from being disclosed to family? Who should make the disclosure, if in fact it is done at all? We conclude by noting that the return of results is increasingly accepted as technology permits the discovery of more and more medically useful data. However, debates of whether results should be returned to participants must first be settled before moving to familial disclosure. (shrink)