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.

This paper presents a philosophical analysis of the structure of black holes, focusing on the event horizon and its fundamental status. While black holes have been at the centre of countless paradoxes arising from the attempt to merge quantum mechanics and general relativity, recent experimental discoveries have emphasised their importance as objects for the development of Quantum Gravity. In particular, the statistical mechanical underpinning of black hole thermodynamics has been a central research topic. The (...) Quantum Membrane Paradigm, proposed by Wallace (Stud Hist Philos Sci Part B 66:103-117, 2019), posits a real membrane made of black hole microstates at the black hole horizon to provide a statistical mechanical understanding of black hole thermodynamics from an exterior observer’s point of view. However, we argue that the Quantum Membrane Paradigm is limited to low-energy Quantum Gravity and needs to be modified to avoid reference to geometric notions, such as the event horizon, which presumably do not make sense in the non-spatiotemporal context of full Quantum Gravity. Our proposal relies on the central dogma of black hole physics. It considers recent developments, such as replica wormholes and entanglement wedge reconstruction, to provide a new framework for understanding the nature of black hole horizons in full Quantum Gravity. (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 investigates the cultural significance of black holes and suns as metaphors in continental European literature and art, drawing on theoretical insights from French continental authors such as Jean-François Lyotard and Ray Brassier. Lyotard suggests that black holes signify the ultimate form of the sublime, representing the displacement of humanity and our unease with our place in the cosmos. On the other hand, Brassier views black holes as a consequence of the entropic dissolution (...) of matter, reflecting physical reality's indifference to subjective or teleological significance. The study also presents a curated collection of literary works and artworks that employ black holes and suns as metaphors, examining the emergence of these metaphorical objects and identifying discursive and epistemological shifts in society. Furthermore, this collaborative research project, involving the Pontifical Catholic University of São Paulo and the Federal Fluminense University in Brazil, and the Charles University in Prague in the Czech Republic, aims to provide a valuable resource for further academic inquiry. (shrink)

This article addresses the challenge philosophical realism poses to the field of rhetoric by exploring the possibility of symbolic communion with nonhuman entities. As a matter of framing, I invoke Timothy Morton’s concept of the hyperobject to better understand the complexities of communicating with and about sublime nonhuman objects such as black holes. I then delineate how the stylistic modality of the weird best exploits the chasm between autonomous thingness and human presentation that is a primary source of (...) consternation for rhetorical realism. Finally, I draw from Kathe Koja’s novel The Cipher to reconsider a bizarre rhetoric of black holes which displays the omnipresent tension of accessible-alterity characteristic of the struggle to rhetorically breach the nonhuman world. (shrink)

Information theory presupposes the notion of an epistemic agent, such as a scientist or an idealized human. Despite that, information theory is increasingly invoked by physicists concerned with fundamental physics, physics at very high energies, or generally with the physics of situations in which even idealized epistemic agents cannot exist. In this paper, I shall try to determine the extent to which the application of information theory in those contexts is legitimate. I will illustrate my considerations using the case of (...) black hole thermodynamics and Bekenstein's celebrated argument for his formula for the entropy of black holes. This example is particularly pertinent to the theme of the present collection because it is widely accepted as `empirical data' in notoriously empirically deprived quantum gravity, even though the laws of black hole thermodynamics have so far evaded direct empirical confirmation. (shrink)

I give a fairly systematic and thorough presentation of the case for regarding black holes as thermodynamic systems in the fullest sense, aimed at students and non-specialists and not presuming advanced knowledge of quantum gravity. I pay particular attention to the availability in classical black hole thermodynamics of a well-defined notion of adiabatic intervention; the power of the membrane paradigm to make black hole thermodynamics precise and to extend it to local-equilibrium contexts; the central role of (...) Hawking radiation in permitting black holes to be in thermal contact with one another; the wide range of routes by which Hawking radiation can be derived and its back-reaction on the black hole calculated; the interpretation of Hawking radiation close to the black hole as a gravitationally bound thermal atmosphere. In an appendix I discuss recent criticisms of black hole thermodynamics by Dougherty and Callender. This paper confines its attention to the thermodynamics of black holes; a sequel will consider their statistical mechanics. (shrink)

Black holes are arguably the most extraordinary physical objects we know in the universe. Despite our thorough knowledge of black hole dynamics and our ability to solve Einstein’s equations in situations of ever increasing complexity, the deeper implications of the very existence of black holes for our understanding of space, time, causality, information, and many other things remain poorly understood. In this paper I survey some of these problems. If something is going to be clear (...) from my presentation, I hope it will be that around black holes science and metaphysics become more interwoven than anywhere else in the universe. (shrink)

I present in detail the case for regarding black hole thermodynamics as having a statistical-mechanical explanation in exact parallel with the statistical-mechanical explanation believed to underly the thermodynamics of other systems. I focus on three lines of argument: zero-loop and one-loop calculations in quantum general relativity understood as a quantum field theory, using the path-integral formalism; calculations in string theory of the leading-order terms, higher-derivative corrections, and quantum corrections, in the black hole entropy formula for extremal and (...) near-extremal black holes; recovery of the qualitative and quantitative structure of black hole statistical mechanics via the AdS/CFT correspondence. In each case I briefly review the content of, and arguments for, the form of quantum gravity being used at a introductory level: the paper is aimed at students and non-specialists and does not presume advanced knowledge of quantum gravity.. My conclusion is that the evidence for black hole statistical mechanics is as solid as we could reasonably expect it to be in the absence of a directly-empirically-verified theory 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)

Presentism is, roughly, the metaphysical doctrine that maintains that whatever exists, exists in the present. The compatibility of presentism with the theories of special and general relativity was much debated in recent years. It has been argued that at least some versions of presentism are consistent with time-orientable models of general relativity. In this paper we confront the thesis of presentism with relativistic physics, in the strong gravitational limit where black holes are formed. We conclude that the (...) presentist position is at odds with the existence of black holes and other compact objects in the universe. A revision of the thesis is necessary, if it is intended to be consistent with the current scientific view of the universe. (shrink)

We present a framework for analyzing black hole backreaction from the point of view of quantum open systems using influence functional formalism. We focus on the model of a black hole described by a radially perturbed quasi-static metric and Hawking radiation by a conformally coupled massless quantum scalar field. It is shown that the closed-time-path (CTP) effective action yields a non-local dissipation term as well as a stochastic noise term in the equation of motion, the Einstein–Langevin equation. (...) Once the thermal Green's function in a Schwarzschild background becomes available to the required accuracy, the strategy described here can be applied to obtain concrete results on backreaction. We also present an alternative derivation of the CTP effective action in terms of the Bogolyubov coefficients, thus making a connection with the interpretation of the noise term as measuring the difference in particle production in alternative histories. (shrink)

So-called ‘existential risks’ present virtually unlimited reasons for probing them and responses to them further. The ensuing normative pull to respond to such risks thus seems to present us with r...

The information loss paradox is often presented as an unavoidable consequence of well-established physics. However, in order for a genuine paradox to ensue, not-trivial assumptions about, e.g., quantum effects on spacetime, are necessary. In this work we will be explicit about these additional, speculative assumptions required. We will also sketch a map of the available routes to tackle the issue, highlighting the, often overlooked, commitments demanded of each alternative. Finally, we will display the strong link between black holes, (...) the issue of information loss and the measurement problem. (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)

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)

In a recent publication in the European Journal for Philosophy of Science, Romero and Pérez claim to reveal new trouble for the already difficult life of presentism in relativistic spacetimes. Their argument purports to demonstrate the impossibility of postulating a viable present in the presence of black holes, in particular the Schwarzschild geometries. I argue that their argument is flawed, and that the Schwarzschild geometries they consider offer no novel threats to presentism. However, if we consider more (...) general black holes, different and more potent threats may be lurking in the dark. I discuss these threats and sketch how a presentist may respond, thus painting a more balanced picture of the way the existence of black holes might impact presentist metaphysics. At present there is no decisive verdict from black holes, but it turns out a close scrutiny of the developments in the relevant physics will be needed to see whether their import will remain so inconclusive. (shrink)

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)

In the standard formalism of quantum gravity, black holes appear to form statistical distributions of quantum states. Now, however, we can present a theory that yields pure quantum states. It shows how particles entering a black hole can generate firewalls, which however can be removed, replacing them by the ‘footprints’ they produce in the out-going particles. This procedure can preserve the quantum information stored inside and around the black hole. We then focus on a subtle (...) but unavoidable modification of the topology of the Schwarzschild metric: antipodal identification of points on the horizon. If it is true that vacuum fluctuations include virtual black holes, then the structure of space-time is radically different from what is usually thought. (shrink)

An analysis of some of the applications of Clifford space relativity to the physics behind the modified black hole entropy-area relations, rainbow metrics, generalized dispersion and minimal length stringy uncertainty relations is presented.

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)

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)

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)

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)

This paper aims to address conceptual issues concerning black holes in the context of string theory, with the aim of illuminating the ontological unification of gravity and matter, and the interpretation of cosmological models. §1 describes the central concepts of the theory: the fungibility of matter and geometry, and the reduction of gravity and supergravity. The ‘standard’ interpretation presented draws on that implicit in the thinking of many (but not all) string theorists, though made more explicit and systematic (...) than usual. §2 explains how to construct a stringy black hole, and some of its features, including evaporation. §3 critically examines the assumptions behind such modeling, and their bearing on ontological questions. (shrink)

The structure of the thermal equilibrium state of a weakly interacting Bose gas is of current interest. We calculate the density matrix of that state in two ways. The most effective method, in terms of yielding a simple, explicit answer, is to construct a generating function within the traditional framework of quantum statistical mechanics. The alternative method, arguably more interesting, is to construct the thermal state as a vector state in an artificial system with twice as many degrees of freedom. (...) It is well known that this construction has an actual physical realization in the quantum thermodynamics of black holes, where the added degrees of freedom correspond to the second sheet of the Kruskal manifold and the thermal vector state is a state of the Unruh or the Hartle–Hawking type. What is unusual about the present work is that the Bogolubov transformation used to construct the thermal state combines in a rather symmetrical way with Bogolubov's original transformation of the same form, used to implement the interaction of the nonideal gas in linear approximation. In addition to providing a density matrix, the method makes it possible to calculate efficiently certain expectation values directly in terms of the thermal vector state of the doubled system. (shrink)

In addition to the traditional attacks from competing legal theories (from natural law to postmodern approach), modern legal positivism seems to be placed at a point of no return when looking at the effects of globalization upon the legal phenomenon. The reality offers to legal positivists countless examples of soft-law, i. e. law which is not law but is perceived and applied by the vast majority of the legal actors as law. Faced with this radically changed reality, most contemporary legal (...) positivists appear to be caught in a dilemma. The modern legal positivism, on one hand, is in front of a reality of legal globalization and increasing legal pluralism in many areas of law, that is a reality (e. g. soft-law) challenging some of the fundamental paradigms endorsed by this legal movement (e. g. the pedigree thesis). On the other hand, modern legal positivists have taken a quite passive attitude toward this challenge, either by abandoning the legal positivism as a whole to its destiny or by simply continuing to focus upon traditional (i. e. pre-globalization) issues as the fundamental ones to be tackled. The goal of this work is to suggest a shift of attention among legal positivists towards questions which have always been present in their program (though often in secondary terms), as also their solutions (often already present in the legal positivist works). This shift would possibly help the legal positivism movement to circumvent the black hole represented by legal globalization (and its legal pluralism), a black hole where the distinction between law and non-law (i. e. the major tenant of legal positivism) seems to vanish, putting the very existence and legitimacy of the legal phenomenon under question. (shrink)

Stephen Hawking is well known for his research on general relativity and black holes. The present work is his attempt to explain his research in a form intelligible to the nonspecialist.

Geoffrey Berg finds a previously undiscovered 'black hole' at the very core of Philosophy. This must cause extensive 'universal uncertainty' that is insurmountable by any human or any intelligence.This book strips away common human delusions about 'goodness', God and the ultimate knowability of the Universe. It focuses on the logical limitations to knowledge for humans, aliens and even artificial intelligences.The book is original and radical, yet entirely logical in its approach. It presents and justifies in quite simple language an (...) entirely different view on philosophical questions to any of the great philosophers. (shrink)

Benefit corporation legislation has rapidly disseminated in the United States. Its advocates claim it is a necessary corporate form to address the unique needs of for-profit social enterprises, despite many scholarly and legal practitioners who doubt the need for or wisdom of adopting this organizational form. Others suggest that the legislation is flawed and deficiencies should be addressed. After reviewing the present status of benefit corporation legislation, this article contributes to the discourse arguing that benefit corporations are unnecessary (...) under the law; benefit corporation legislation does not enhance corporate law; benefit corporation laws create unnecessary new legal risks for both traditional and benefit corporations, and their respective directors; and third party certification in entity formation law is inappropriate. (shrink)

During the 1970s, Dinu Adamesteanu uncovered a small sacred place within the chora of Heraklea. It is an open-air sanctuary, constituted by an area bounded by a temenos wall, with an altar and a small naiskos inside. A votive deposit was located within the temenos, which was filled with a large quantity of ritual and votive material, placed in the hole when the sacred place was abandoned. The architectural structures and a selection of the finds were first published by Dinu (...) Adamesteanu himself. He identified this small sacred place with Chalcas’ heroon, which is recorded in Lycophron’s famous passage. The subject of this contribution is a comprehensive re-examination of this sacred place – architectural structures as well as published and un-published finds – which allows us to present a different scenario from that first proposed by Adamesteanu. Most of the Black-Glaze vases pertain to the practice of the symposium, while the common wares suggest that food was usually prepared in order to be given as a gift to deities. The Red-Figure vases present interesting figural depictions, which tend to refer to Dionysian subjects and to the theme of weddings. With regard to coroplastic objects, three fragmentary life-size terracotta statues have been found. At least two of these represent young, beautiful women, seated on thrones and wearing lavish clothes. A number of small terracotta figurines show diverse iconographies, which pertain to the spheres of kourotropheia and sanatio, but there are also “erotic” subjects, referring to the Aphrodisian sphere, and votive clay fruits, which suggest the chthonian aspect of this cult. In light of this comprehensive analysis of archaeological data, a clearer and more detailed picture emerges of the Contrada Petrulla sanctuary. The sacred area was probably dedicated to feminine deities, who can be identified with the Nymphs, peripheral figures of Aphrodite’s circle. These feminine deities who have chthonian characteristics, personify water (generally a water spring), oversee the passage from a virginal condition to the status of nymphai, have a kourotrophic nature, and are ultimately associated with the Dionysian world. Therefore, the life-size seated statues found in the votive deposit can be considered as cult statues (depictions of the Nymphs themselves?). Previously, the statues had been located in the small naiskos, which was placed within the temenos wall and was open to the altar. (shrink)

The existence of White Hole (WH) has been suggested by Schwarzschild solution to the Einstein field equation as a time-reversed Black Hole (BH), besides there has not been observational evidence for their existence yet. Our idea of the “inverse universe”, in which we introduce the time-reversed kinematics as another geometric state, can explain that WH should appear in such a geometry after a matter falls into a BH. In this work, we present a new operation for WH conversion (...) from BH, and by using it the nearly infinity point on the universe, for instance the inside of BH, is geometrically connected to the inside of WH on the inverse universe. Such a conversion is useful to provide the simple solution to the problem of “information loss” in BH. Furthermore, we find another conversion point as the prior geometric state to the Big Bang, and we propose a new cosmology of cyclic universe. (shrink)

Taking the formal analogies between black holes and classical thermodynamics seriously seems to first require that classical thermodynamics applies in relativistic regimes. Yet, by scrutinizing how classical temperature is extended into special relativity, I argue that the concept falls apart. I examine four consilient procedures for establishing the classical temperature: the Carnot process, the thermometer, kinetic theory, and black-body radiation. I argue that their relativistic counterparts demonstrate no such consilience in defining the relativistic temperature. As such, classical (...) temperature doesn’t appear to survive a relativistic extension. I suggest two interpretations for this situation: eliminativism akin to simultaneity, or pluralism akin to rotation. (shrink)

In _The Long Emancipation_ Rinaldo Walcott posits that Black people globally live in the time of emancipation and that emancipation is definitely not freedom. Taking examples from across the globe, he argues that wherever Black people have been emancipated from slavery and colonization, a potential freedom has been thwarted. Walcott names this condition the long emancipation—the ongoing interdiction of potential Black freedom and the continuation of the juridical and legislative status of Black nonbeing. Stating that (...) Black people have yet to experience freedom, Walcott shows that being Black in the world is to exist in the time of emancipation in which Black people must constantly fashion alternate conceptions of freedom and reality through expressive culture. Given that Black unfreedom lies at the center of the making of the modern world, the attainment of freedom for Black people, Walcott contends, will transform the human experience worldwide. With _The Long Emancipation_, Walcott offers a new humanism that begins by acknowledging that present conceptions of what it means to be human do not currently include Black people. (shrink)

In this article, I use in-depth interviews with Black college students at two predominantly white universities to investigate the coconstruction of race, gender, and sexuality, and to examine intersectional identities as a dynamic process rather than bounded identity. I focus on Black college men’s talk about interracial relationships. Existing research documents Black women’s angry reactions to interracial relationships, but for Black men, interracial relationships present both problems and opportunities. I examine how Black men use (...) two distinct forms of interracial talk— “player” talk and “intimacy” talk—to negotiate racialized gendered stereotypes of Black men’s heterosexuality. By moving between forms of talk, Black men negotiate the identity tensions they face as Black upwardly mobile men. Player talk and intimacy talk both respond to and use racialized stereotypes, reworking the relationship between gender, race, and sexuality. In this case, disrupted racial boundaries uphold gender inequalities between men and women. (shrink)

Crane envisions the speculative conjecture that intelligent civilizations might want and be able to produce black holes in the very far future. He implicitly suggests two main purposes of this enterprise: (i) energy production and (ii) universe production. We discuss those two options. The commentary is obviously highly speculative and should be read accordingly.

In spite of heralded progress in civil rights, this paper pessimistically maintains that blacks are systematically excluded from directorships on the boards of the major industrial companies in this country. The statistics derived from a 1980 survey, which yielded responses from 143 companies, show that blacks constituted only 1.9 percent of the entire directorate pool, with no black chairmen, no company with more than one black director, and significantly high multiple-board service on the part of a few (...) class='Hi'>black directors. There is a strong correlation between size and importance of a company and black directorships, as well as between longer-range company commitments and white male directorships. There is discussion of answers from board members relating to constituency representation, philosophy regarding black recruitment and reasons for the paucity of black representation. After drawing a profile of typical boards, the study shows how the pool of individuals traditionally eligible to serve as directors virtually excludes blacks, confining them to rigid and narrow categories, and concludes that the "white club" remains white because it is insulated by an inflexible system whose inequity has been internalized and whose existence current directors would rather not acknowledge. While admitting the difficulty of discussing and even defining the existence of tokenism, the paper looks at the phenomenon of single-black-member boards, questioning the status, use and professions of some black directors. In the context of a climate that encourages governmental mandating of corporate responsibility, the authors suggest that corporate initiative wisely be generated toward achieving more equitable balances in the highest economic echelons where black impotence, given the present system, can neither be remedied nor tolerated much longer. (shrink)

In light of Ruth Wilson Gilmore’s call that abolition means to “change everything,” how might we understand an abolitionist literary method? An abolitionist literary method dials into the language of critiquing prisons. This essay contends that recent developments in U.S. discourse concerning prison reform and prison abolition rely on the distinction between metaphor and metonymy. As rhetorical tropes, metaphor and metonymy both operate by means of figurative language. Metaphor creates a parallel formation between terms, popular in prison reformist language (i.e. (...) “prison as labor,” “prison as slavery,” “schools as prisons,” or “black holes as prisons”), while metonymy demonstrates a network between materially related sites, persons, and objects (as in “flesh,” “black holes,” or “the Prison Industrial Complex”) more central to the rhetoric of prison abolition. Following Emily Apter’s critique of Fredric Jameson’s “carceral metaphors,” I demonstrate these distinctions between metaphor-reform and metonymy-abolition through textual analysis of a Black feminist archive by considering the work of Ruth Wilson Gilmore, Hortense Spillers, Saidiya Hartman, George Jackson, Evelynn Hammonds, and Assata Shakur. These different thinkers employ metonymy to illuminate theoretical possibilities for abolition through economics, flesh, motherhood, intimacy, sexuality, and physics over a period of thirty years. That being said, none of these writers define their work by the principal status given to metonymy, and this essay seeks to bring together their interventions through this rhetorical trope. I propose that abolition’s stretch through metonymy is central to an abolitionist literary method, provoking the animated reconsideration of language-use by scholars and activists. While not eliding metaphor entirely, this historical materialist work demonstrates that the careful elaboration of words and phrases becomes more robustly anti-carceral when one indexes where, how, and why metaphor and metonymy contract or extend imaginative political possibility. (shrink)

Although the laws of thermodynamics are well established for black hole horizons, much less has been said in the literature to support the extension of these laws to more general settings such as an asymptotic de Sitter horizon or a Rindler horizon (the event horizon of an asymptotic uniformly accelerated observer). In the present paper we review the results that have been previously established and argue that the laws of black hole thermodynamics, as well as their underlying (...) statistical mechanical content, extend quite generally to what we call here “causal horizons.” The root of this generalization is the local notion of horizon entropy density. (shrink)

We review some ideas about the quantum physics of black hole information storage and processing in terms of a general phenomenon of quantum criticality.

Jacob Bekenstein's identification of black hole event horizon area with entropy proved to be a landmark in theoretical physics. In this paper we trace the subsequent development of the resulting generalized second law of thermodynamics (GSL), especially its extension to incorporate cosmological event horizons. In spite of the fact that cosmological horizons do not generally have well-defined thermal properties, we find that the GSL is satisfied for a wide range of models. We explore in particular the case of an (...) asymptotically de Sitter universe filled with a gas of small black holes as a means of casting light on the relative entropic ‘worth’ of black hole versus cosmological horizon area. We present some numerical solutions of the generalized total entropy as a function of time for certain cosmological models, in all cases confirming the validity of the GSL. (shrink)

To what extent does the black hole information paradox lead to violations of quantum mechanics? I explain how black hole complementarity provides a framework to articulate how quantum characterizations of black holes can remain consistent despite the information paradox. I point out that there are two ways to cash out the notion of consistency in play here: an operational notion and a descriptive notion. These two ways of thinking about consistency lead to (at least) two principles (...) of black hole complementarity: an operational principle and a descriptive principle. Our background philosophy of science regarding realism/instrumentalism might initially lead us to prefer one principle over the other. However, the recent physics literature, which applies tools from quantum information theory and quantum computational complexity theory to various thought experiments involving quantum systems in or around black holes, implies that the operational principle is successful where the descriptive principle is not. This then lets us see that for operationalists the black hole information paradox might no longer be pressing. (shrink)

The black hole information paradox arises from an apparent conflict between the Hawking black hole radiation and the fact that time evolution in quantum mechanics is unitary. The trouble is that while the former suggests that information of a system falling into a black hole disappears, the latter implies that information must be conserved. In this work we discuss the current divergence in views regarding the paradox, we evaluate the role that objective collapse theories could play in (...) its resolution and we propose a link between spontaneous collapse events and microscopic virtual black holes. (shrink)

Surface presentism is the combination of a general relativistic physics with a presentist metaphysics. In this paper, we provide an argument against this combination based on black holes. The problem focuses on the notion of an event horizon. We argue that the present locations of event horizons are ontologically dependent on future black hole regions, and that this dependence is incompatible with presentism. We consider five responses to the problem available to the surface presentist, and argue (...) that none succeed. Surface presentism thus faces the prospect of refutation based on evidence that confirms the existence of black holes. (shrink)

Removing a black hole conic singularity by means of Kruskal representation is equivalent to imposing extensibility on the Kasner–Fronsdal local isometric embedding of the corresponding black hole geometry. Allowing for globally non-trivial embeddings, living in Kaluza–Klein-like M 5 × S 1 (rather than in standard Minkowski M 6 ) and parametrized by some wave number k, extensibility can be achieved for apparently “forbidden” frequencies ω in the range ω 1 (k) ≤ ω ≤ ω 2 (k). As k (...) → 0, ω 1, 2 (0) → ωH (e.g., ωH = 1/4M in the Schwarzschild case) such that the Hawking–Gibbons limit is fully recovered. The various Kruskal sheets are then viewed as slices of the Kaluza–Klein background. Euclidean k discreteness, dictated by imaginary time periodicity, is correlated with flux quantization of the underlying embedding gauge field. (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)