Measuring the rate at which the universe expands at a given time–the ‘Hubble constant’– has been a topic of controversy since the first measure of its expansion by Edwin Hubble in the 1920s. As early as the 1970s, Sandage and de Vaucouleurs have been arguing about the adequate methodology for such a measurement. Should astronomers focus only on their best indicators, e.g., the Cepheids, and improve the precision of this measurement based on a unique object to the (...) best possible? Or should they “spread the risks”, i.e., multiply the indicators and methodologies before averaging over their results? Is a robust agreement across several uncertain measures, as is currently argued to defend the existence of a ‘Hubble crisis’ more telling than a single 1% precision measurement? This controversy, I argue, stems from a misconception of what managing the uncertainties associated with such experimental measurements require. Astrophysical measurements, such as the measure of the Hubble constant, require a methodology that permits both to reduce the known uncertainties and to track the unknown unknowns. Based on the lessons drawn from the so-called Hubble crisis, I sketch a methodological guide for identifying, quantifying and reducing uncertainties in astrophysical measurements, hoping that such a guide can not only help to re-frame the current Hubble tension, but serve as a starting point for future fruitful discussions between astrophysicists, astronomers and philosophers. (shrink)

Following a bi-cylindrical model of geometrical dynamics, our study shows that a 6D-gravitational equation leads to geodesic description in an extended symmetrical time–space, which fits Hubble-like expansion on a microscopic scale. As a duality, the geodesic solution is mathematically equivalent to the basic Klein–Gordon–Fock equations of free massive elementary particles, in particular, the squared Dirac equations of leptons. The quantum indeterminism is proved to have originated from space–time curvatures. Interpretation of some important issues of quantum mechanical reality (...) is carried out in comparison with the 5D space–time–matter theory. A solution of lepton mass hierarchy is proposed by extending to higher dimensional curvatures of time-like hyper-spherical surfaces than one of the cylindrical dynamical geometry. In a result, the reasonable charged lepton mass ratios have been calculated, which would be tested experimentally. (shrink)

One of the outstanding achievements of recent cosmology has been to offer some prospect of a unified explanation of temporal asymmetry. The explanation is in two main parts, and runs something like this. First, the various asymmetries we observe are all thermodynamic in origin – all products of the fact that we live in an epoch in which the universe is far from thermodynamic equilibrium. Second, this thermodynamic disequilibrium is associated with the condition of the universe very soon after the (...) Big Bang – the essential point being that in the rapidly expanding universe of the time, gravity is able to create organisation much faster than other processes can destroy it. The stars, galaxies and other forms of organisation we find in the present universe are all products of this early period. Such concentrated energy sources themselves make possible the kinds of asymmetric phenomena with which we are most familiar, such as life itself. If this explanation proves to be right it will surely rank as one of the most impressive achievements in the whole of natural philosophy. Where else do we find this breathtaking scale, this extraordinary conjunction of fundamental physics, the first moments of Creation, the possibility of life and the basic character of human experience? And it is very much a contemporary achievement: even if its roots go back on one side to the investigation of time asymmetry in nineteenth century statistical mechanics, and on the other to Hubble's discovery in the 1920's of the expansion of the universe, the body of the picture has only begun to be filled in in the last twenty or thirty years. This fascinating story has recently been given some well-deserved publicity in Stephen Hawking's bestseller, A Brief History of Time – well-deserved, not least, because Hawking himself is responsible for a considerable part of the story as it presently stands. (shrink)

The development of physical theory is one of our greatest intellectual achievements. Its products--the currently prevailing theories of physics, astronomy, and cosmology--have proved themselves to possess intrinsic beauty and to have enormous explanatory and predictive power. This anthology of primary readings chronicles the birth and maturation of five such theories (the heliocentric theory, the electromagnetic field theory, special and general relativity, quantum theory, and the big bang theory) in the words of the scientists who brought them to life. It is (...) the first historical account that captures the rich substance of these theories, each of which represents a fascinating story of the interplay of evidence and insight--and of dialogue among great minds. Readers sit in with Copernicus, Kepler, and Galileo as they overturn the geocentric universe; observe the genius of Faraday and Maxwell as they "discover" the electromagnetic field; look over Einstein's shoulder as he works out the details of relativity; listen in as Einstein and Bohr argue for the soul of quantum mechanics in the Completeness Debate; and watch as Hubble and others reveal the history of the universe. The editors' approach highlights the moments of discovery that rise from scientific creativity, and the presentation humanizes the scientific process, revealing the extent to which great scientists were the first to consider the philosophical implications of their work. But, most significantly, the editors offer this as their central thesis: although each was ushered in by a revolution, and each contains counterintuitive elements that delayed its acceptance, these five theories exhibit a continuous rational development that has led them to a permanent place in the worldview of science. Accessible to the general reader yet sufficiently substantive that working scientists will find value in it, The Tests of Time offers an intimate look into how physical theory has been developed, by the brilliant people who have developed it. (shrink)

The cover page of John Gribbin's The Birth of Time, listing more than thirty books he has written on astronomy, physics, and general science, shows the success this author has had in making these subjects interesting to and understandable by the general public. The eight chapters of The Birth of Time, ending with a useful list of books for further reading and a well‐compiled index, do indeed present a readable account of a difficult subject: man's attempts, from the (...) time of the ancient Greeks onward, to understand what is out in the sky and our place in that world. The book contains no mathematics and can be enjoyed by general readers, high school students, and teachers.The first chapter is historical: an account of the progression from Arabic science at the end of the first millennium, including the discovery and recognition of fossils as indicators of a geological history of the earth, through the seventeenth century's beginnings of an attempt to understand this history. The second chapter provides an account of the twentieth century's growing knowledge of the physics of stars, with nuclear energy as the source of their outpouring radiation. The fundamental work of Sir Arthur Eddington at the University of Cambridge is described here, and a simple account is given of the evolution of stars, from their formation from clouds of gas and dust to their eventual death as spectacular explosions or as cold, inert lumps of mass.Only in Chapter 3 does the author get to the real basic techniques of distance measurement, starting with triangulation by surveyors on the earth's surface and proceeding with ever‐increasing baselines, as Copernicus, Tycho Brahe, and Galileo made their impact on our understanding of the solar system and measurement of the earth's distance from the sun made this baseline the tool for distance measurements of stars.The concept of “standard candles”—stars whose intrinsic luminosities could be determined and whose apparent brightness could be measured, thus yielding their distances—is described next. A fair description is given of the epochal discovery in 1912 by Henrietta Leavitt, working at the Harvard College Observatory on routine measurement of variable stars on photographic plates, of our nearest neighbor galaxy, the Small Magellanic Cloud. She discovered a tight relationship between the periods of variation of a certain class of variable stars, the Cepheids, with their overall brightness, thus giving posterity the most important starting tool for distance measurements of galaxies outside the Milky Way.As Gribbin takes readers through the history of the gradual understanding of the place of our home galaxy, the Milky Way, in the universe at large, the work of various heroes of these progressive discoveries and the pitfalls encountered by others are described, somewhat unevenly. The astronomer Vesto Slipher, observing the spectra of galaxies with the twenty‐four‐inch telescope at Lowell Observatory in northern Arizona, receives due credit for the first measurement of line‐of‐sight recession velocities of galaxies, from the Doppler shift of atomic lines in their spectra toward the red end of the spectrum. The role of Milton Humason, former mule driver, janitor, and eventually the famous associate of Edwin Hubble, in the discovery from these redshifts of the expansion of spacetime is well described. Allan Sandage, a former Hubble pupil who is clearly Gribbin's hero, might himself demur at the enthusiasm with which his work is described; while Gerard de Vaucouleurs, were he still with us, would not be pleased with the account of his work that led to a value for the Hubble Constant—the quantity that converts measured recession velocities of galaxies to their distances from us—twice that determined by Sandage.The description of Gribbin's own recent research , which he describes as “just one minor brick in the scientific edifice” , based as it was on his belief that our sun and solar system exist in a very ordinary average‐sized spiral galaxy, is quite interesting. It follows a chapter giving an account of recent additions to the arsenal of astronomers' tools for distance measurement in the universe—and also the nasty systematic biases that can slant the result away from what one hopes is correct.The book is illustrated by eight nicely printed pages of images obtained by the Hubble Space Telescope. It is easy to read and tells its story in a friendly, chatty style. Though it concludes by suggesting a value of some 13 billion years ago as the epoch of “the birth of time,” the discerning reader will realize that the story is still evolving and that surprises can be expected. (shrink)

The theory is based on an original alternative space-time concept that leads to a new vision of the micro-cosmos and Universe. The relationship between the forces in Nature is unveiled by adopting the following framework: (1) Empty space without any physical properties and restrictions; (2) Two fundamental particles of superdense protomatter with parameters associated with Planck’s scale; (3) A Fundamental law of Supergravitation (SG) with forces inversely proportional to the cube of distance in a pure empty space. An enormous (...) abundance of these two particles, with vibrational energy beyond some critical level, can congregate into self-organized hierarchical levels of 3D formations, governed by the SG law. The process leads deterministically to creating space with quantum mechanical properties and a galaxy as an observable mattter. The fundamental SG law is behind the gravitational, electric, and magnetic fields and governs all kinds of interactions between the elementary particles in the space of the physical vacuum. Analysis of cosmological observations reveals that the galaxies possess their own cycle in which the elementary particles are formed at a hidden non-observable phase. The problem of departure of the Hubble plot from the predicted one is solved, showing that the redshift is not of Doppler origin. The conclusion is that the Universe is stationary and eternal. (shrink)

Kurt Gödel, mathematician and logician, was one of the most influential thinkers of the twentieth century. Gödel fled Nazi Germany, fearing for his Jewish wife and fed up with Nazi interference in the affairs of the mathematics institute at the University of Göttingen. In 1933 he settled at the Institute for Advanced Study in Princeton, where he joined the group of world-famous mathematicians who made up its original faculty. His 1940 book, better known by its short title, The Consistency of (...) the Continuum Hypothesis, is a classic of modern mathematics. The continuum hypothesis, introduced by mathematician George Cantor in 1877, states that there is no set of numbers between the integers and real numbers. It was later included as the first of mathematician David Hilbert's twenty-three unsolved math problems, famously delivered as a manifesto to the field of mathematics at the International Congress of Mathematicians in Paris in 1900. In The Consistency of the Continuum Hypothesis Gödel set forth his proof for this problem. In 1999, Time magazine ranked him higher than fellow scientists Edwin Hubble, Enrico Fermi, John Maynard Keynes, James Watson, Francis Crick, and Jonas Salk. He is most renowned for his proof in 1931 of the 'incompleteness theorem,' in which he demonstrated that there are problems that cannot be solved by any set of rules or procedures. His proof wrought fruitful havoc in mathematics, logic, and beyond. (shrink)

It has been known for long time that most of the existing cosmology models have singularity problem. Cosmological singularity has been a consequence of excessive symmetry of flow, such as “Hubble’s law”. More realistic one is suggested, based on Newtonian cosmology model but here we include the vertical-rotational effect of the whole Universe. We review a Riccati-type equation obtained by Nurgaliev, and solve the equation numerically with Mathematica. It is our hope that the new proposed method can be (...) verified with observation data. (shrink)

It is proposed to remove the difficulty of nonitegrability of length in the Weyl geometry by modifying the law of parallel displacement and using “standard” vectors. The field equations are derived from a variational principle slightly different from that of Dirac and involving a parameter σ. For σ=0 one has the electromagnetic field. For σ<0 there is a vector meson field. This could be the electromagnetic field with finite-mass photons, or it could be a meson field providing the “missing mass” (...) of the universe. In cosmological models the two natural gauges are the Einstein gauge and the cosmic gauge. With the latter the universe has a fixed size, but the sizes of small systems decrease with time and their masses and energies increase, thus producing the Hubble effect. The field of a particle in this gauge is investigated, and it leads to an interesting solution of the Einstein equations that raises a question about the Schwarzschild solution. (shrink)

The claim of inflationary cosmology to explain certain observable facts, which the Friedmann-Roberston-Walker models of `Big-Bang' cosmology were forced to assume, has already been the subject of significant philosophical analysis. However, the principal empirical claim of inflationary cosmology, that it can predict the scale-invariant power spectrum of density perturbations, as detected in measurements of the cosmic microwave background radiation, has hitherto been taken at face value by philosophers. The purpose of this paper is to expound the theory of density perturbations (...) used by inflationary cosmology, to assess whether inflation really does predict a scale-invariant spectrum, and to identify the assumptions necessary for such a derivation. The first section of the paper explains what a scale invariant power-spectrum is, and the requirements placed on a cosmological theory of such density perturbations. The second section explains and analyses the concept of the Hubble horizon, and its behaviour within an inflationary space-time. The third section expounds the inflationary derivation of scale-invariance, and scrutinises the assumptions within that derivation. The fourth section analyses the explanatory role of `horizon-crossing' within the inflationary scenario. (shrink)

In the early 1950s, astronomer Allan Sandage inherited from Edwin Hubble the task of determining whether expansion was real. In the succeeding forty years, Sandage “established the discipline of observational cosmology” (Overbye 1991, 188). At the same time, he encountered the limits of science to address the full mystery of existence. In seeking an answer to the question of purpose, in particular, Sandage came to the “abyss of reason” and made the “leap of faith.” This conversion, however, involved, (...) and continues to involve, an ongoing process of balancing two avenues to the truth, drawing upon resources from both scientific and religious traditions. Reason and faith seem reconcilable in life lived as an experiment and in “bowing before the mystery” (Sandage 1990). Ultimately, Sandage suggests that religious conversion comes not so much through reasoned pursuit as in the realization of being pursued. (shrink)

Today we know, and this will be the subject of this article, that the universe is in continuous evolution, even revolution. This observation has been possible only quite recently. It was necessary to wait for the observations of distant galaxies, undertaken between 1930 and 1950 by Edwin P. Hubble, the astronomer who was the first to show that the universe as a whole is presently expanding. We know now also that the form of the constellations closest to us, such (...) as the Great Bear, has been modified over the last millennia. Ancient astronomers, and with them the rest of humanity, imagined at that time that the universe was eternal and unchangeable. Astrophysicists today are convinced, in the large majority, that twenty billion years ago the universe went through a unique phase during which it was very hot and very dense. To this phenomenon they have given the name of the original or primordial explosion. As will be seen later, certain people believe that the universe will once again experience this great “heat”, which will be generated during future contractions. Others foresee an increasingly frozen and empty future for the universe. Between this glorious past and this uncertain future, the universe each day reveals more of its splendor thanks to the arrival of modern techniques of observation and the beginning of the conquest of space. The purpose of this article is to give a brief survey of the manner in which astronomers see the universe today; working from the position of man in the universe, his relation to it begins to be understood better. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Destruction and Transcendence in W. G. SebaldMark R. McCullohIFor all the Saturnine pessimism of W. G. Sebald's application of Walter Benjamin's view of historical process (an attitude toward history expounded upon at length in an influential work by Susan Sontag), the author's sense of irony about the human predicament is irrepressible. 1 Human beings seem destined to remain prisoners of various paradoxes—they both create and destroy, they are capable (...) of acts of love as well as bitterness and hate, they make efforts to document and communicate, but at the same time they tend to forget and are given to suppressing the truth, they are driven by ideals, yet remain hobbled by imperfection. Art and music, passed on from generation to generation, seem to be the most common way that human beings transcend the strictures of their imperfections, inadequacies, and their finitude. And to the extent that art indeed survives over time, and continues to be perceived and appreciated by beholders, the aesthetic enterprise succeeds. However, ultimately, as the Book of Ecclesiastes and Shelley's "Ozymandias" remind us, all human endeavor is in vain, and, to assume the perspective of physical cosmology for a moment—and in this regard Benjamin's cosmic vision appears painfully accurate—our speck of earth, dwarfed by a vast universe the true immensity of which has been revealed by the Hubble Telescope, will one day be ground to dust and debris like the rings of Saturn, and our sun will exist only as a burned-out hulk. But such a future world, devoid of beholders, and devoid of creators and their artifacts, is not Sebald's primary subject, even though it clearly forms the teleological backdrop for his third novel, The Rings of Saturn (1995, English version 1998). Rather, Sebald pursues his art in spite of a terminal prospect that will ultimately confront our [End Page 395] planet and solar system. His primary subject, the effect of trauma on individual and collective experience, is instead closely linked with the passing of Europe as a tradition, as an idea—as an idiosyncratic and innovative, but inherently corrupt contributor to cultural history. In the course of his narratives he also addresses the redemptive role of art in memorializing the past and attempting to capture the passing present. In both respects he attends to the humane and the sublime as well as the tragic and the grotesque.Paraphrasing the art historian Svetlana Alpers, one early reviewer of Sebald's novel Austerlitz (2001) points out the self-contradictory nature of preserving the transient moment in art:Why create visual art at all when everything on earth must be represented in its inexorable transitoriness; why paint earthly scenes with such incredible care and precision as if they were permanent? 2The care and precision of the painter's craft (in this case, the Dutch still-life painter David Bailly) are devoted to the representation of a scene that is by its very nature transient and even tenuous—like the scenes of sublime beauty in Sebald's fiction, the artist's depiction "courts and admits" its own fragility. What Bailly does visually, Sebald attempts in words. Take, for instance, the following passage from Vertigo, Sebald's first novel, which was titled in German (with considerably more irony) Schwindel. Gefühle 3 :At a hairpin bend I looked out of the turning bus down into the depths below and could see the turquoise surfaces of the Ferstein and Smaranger lakes, which, even when I was a child, on our first excursions into the Tyrol, had seemed to me the essence of all conceivable beauty.(p. 176)The author has already prepared the reader for this moment of awe by remarking on the otherworldly "slow-motion quality" of the waterfalls descending from the mountain cliffs and on the boulders in their screes spreading downwards into the wooded hillsides, "screes which reached from the mountains down into the forests like pale fingers into dark hair..." (p. 176). Examined closely, the passage in question suggests both the enduring power of natural beauty and, especially with its precise reference to an automobile long since out of production and unfamiliar to... (shrink)

I’ve just discovered that the Abstract painting has similarities not only with the micro-cosmos (as it is stated in the book “Man and His Symbol” by dr. CG Jung) but also, which is very astonishing, with the macro-Cosmos. Shortly, Hilma af Klint painted in her “The Ten Largest” symbols that are amazingly similar with modern astro-physics pictures that were made, many decades later, by the Hubble Telescope (and were not available for human eyes on the af Klint times). The (...) research aim is to prove that the human mind capacity for producing symbols with connection to the future science (see the known example of chemist August Kekule and the benzene formula) is bigger than it was thought. The research method is based on personal specific skills that are focused on deciphering scientifical and cultural symbols. Based on my technique that I developed in a couple of years, I managed to publish articles like “Fibonacci Numbers in Cucuteni Culture” on the “History Files” portal or “Mathematical equation, hidden in Brâncusi’s Triptych from Târgu-Jiu”. But my discovery about Hilma af Klint is the greatest. (shrink)

Under the assumption that Hubble's constant H0 is constant in cosmic time, there is an analogy between the equation of propagation of light and that of expansion of the universe. Using this analogy, and assuming that the laws of physics are the same at all cosmic times, a new special relativity, a cosmological relativity, is developed. As a result, a transformation is obtained that relates physical quantities at different cosmic times. In a one-dimensional motion, the new transformation is (...) given by $$x' = \frac{{x - Tv}}{{(1 - T^2 /T_0^2 )^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} }},v' = \frac{{v - xT/T_0^2 }}{{(1 - T^2 /T_0^2 )^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} }}$$ where x and v are the coordinate and velocity, T is the cosmic time measured backward with respect to our present time T=0, tand T0 is Hubble's time.Some consequences of this transformation are given, and its applicability limitation is pointed out. (shrink)

The Robertson–Walker (RW) metric allows us to apply general relativity to model the behavior of the Universe as a whole (i.e., cosmology). We can properly interpret various cosmological observations, like the cosmological redshift, the Hubble parameter, geometrical distances, and so on, if we identify fundamental observers with individual galaxies. That is to say that the interpretation of observations of modern cosmology relies on the RW metric. The RW model satisfies the cosmological principle in which the 3-space always remains isotropic (...) and homogeneous. One can derive the cosmological redshift relation from this condition. We show that it is still possible for us to obtain consistent results in a specific time-varying speed-of-light model without spoiling the success of the standard model. The validity of this model needs to be determined by observations. (shrink)

The present authors have given a mathematical model of Mach's principle and of the Mach–Einstein doctrine about the complete induction of the inertial masses by the gravitation of the universe. The analytical formulation of the Mach–Einstein doctrine is based on Riemann's generalization of the Lagrangian analytical mechanics (with a generalization of the Galilean transformation) on Mach's definition of the inertial mass and on Einstein's principle of equivalence. All local and cosmological effects—which are postulated as consequences of Mach's principle by C. (...) Neumann, Mach, Friedländer and Einstein—result from the Riemannian dynamics with the Mach–Einstein doctrine. In celestial mechanics it follows, in addition, Einstein's formula for the perihelion motion. In cosmology, the Riemannian mechanics yields two models of an evolutionary universe with the expansion lows R ~ t or R ~ t2. In this paper, secular consequences of the Mach–Einstein doctrine are examined concerning palaeogeophysics and celestial mechanics. The research predicted secular decrease of the Earth's flattening and secular acceleration of the motion of the Moon and of the planets. The numerical values of this secular effect agree very well with the empirical facts. In all cases, the secular variation $\dot{\alpha}$ of the parameter α is the order of magnitude $\dot{\alpha}=-H_0 \alpha$ , where H0 is the instantaneous value of the Hubble constant: $H_0 =\left({\dot{R}/R} \right)_0 \approx \left( {0.5-1.0} \right) \times 10^{-10}a^{-1}$ . The relation of the secular consequences of the Mach–Einstein doctrine to those of Dirac's hypothesis on the expanding Earth, and to Darwin's theory of tidal friction are also discussed. (shrink)

This article explores the relation between two different modes of cosmology: the social and the scientific. Over the twentieth century, scientific understandings of the dimensions and operations of the physical universe changed dramatically, significantly prompted by astronomical and astrophysical research undertaken at the Mount Wilson Observatory in Pasadena, California. Could those understandings be readily translated into social theory? Studies across a range of disciplines have intimated that the scientific cosmos might be less essential to the worlds of meaning and belonging (...) that people and communities compose around themselves than more local and relational models of an ordered whole. The article applies that proposition to the Mount Wilson Observatory itself, arguing that the observatory’s founder, George Ellery Hale, and his acolytes were deeply invested in practices of terrestrial place-making, the politics of belonging, and the cadences of civilizational time as applied to their city and its region. Moreover, they struggled to construct a philosophy integrating the cosmos they were seeking to fix at home with the contortions and careering trajectories of the universal whole. (shrink)

Cosmology as Weltanschauung is as old as the world. Cosmology as a physical discipline, however, is a child of this century, born in 1917, when Albert Einstein and Willem de Sitter first applied the theory of general relativity to the space-time of the entire universe. When did the child come of age and become a fully-fledged science? A popular myth shared by many practitioners holds that this did not happen until 1965, when the discovery of the 2.7K cosmic microwave (...) background radiation validated the concept of the hot big bang. Earlier accomplishments culminating in the 1965 event include the derivation of evolving relativistic models by Alexander Friedmann and George Lemaître, Edwin Hubble’s discovery of the redshift-magnitude relationship and George Gamow’s theory of the primordial nucleosynthesis containing the prediction of the microwave background left from the hot and dense past of the universe. This linear development is thrown into sharper relief in textbooks, by referring to an inarticulate.. (shrink)

Today we are all familiar with the iconic pictures of the nebulae produced by the Hubble Space Telescope’s digital cameras. But there was a time, before the successful application of photography to the heavens, in which scientists had to rely on handmade drawings of these mysterious phenomena. Observing by Hand sheds entirely new light on the ways in which the production and reception of handdrawn images of the nebulae in the nineteenth century contributed to astronomical observation. Omar W. (...) Nasim investigates hundreds of unpublished observing books and paper records from six nineteenth-century observers of the nebulae: Sir John Herschel; William Parsons, the third Earl of Rosse; William Lassell; Ebenezer Porter Mason; Ernst Wilhelm Leberecht Tempel; and George Phillips Bond. Nasim focuses on the ways in which these observers created and employed their drawings in data-driven procedures, from their choices of artistic materials and techniques to their practices and scientific observation. He examines the ways in which the act of drawing complemented the acts of seeing and knowing, as well as the ways that making pictures was connected to the production of scientific knowledge. An impeccably researched, carefully crafted, and beautifully illustrated piece of historical work, Observing by Hand will delight historians of science, art, and the book, as well as astronomers and philosophers. (shrink)

We propose that whatever quantity controls the Heisenberg uncertainty relations it should be identified with an effective Planck parameter. With this definition it is not difficult to find examples where the Planck parameter depends on the region under study, varies in time, and even depends on which pair of observables one focuses on. In quantum cosmology the effective Planck parameter depends on the size of the comoving region under study, and so depends on that chosen region and on (...) class='Hi'>time. With this criterion, the classical limit is expected, not for regions larger than the Planck length, \, but for those larger than \^{1/3}\), where H is the Hubble parameter. In theories where the cosmological constant is dynamical, it is possible for the latter to remain quantum even in contexts where everything else is deemed classical. These results are derived from standard quantization methods, but we also include more speculative cases where ad hoc Planck parameters scale differently with the length scale under observation. Even more speculatively, we examine the possibility that similar complementary concepts affect thermodynamical variables, such as the temperature and the entropy of a black hole. (shrink)

In his [1937, 1938], Paul Dirac proposed his “Large Number Hypothesis” (LNH), as a speculative law, based upon what we will call the “Large Number Coincidences” (LNC’s), which are essentially “coincidences” in the ratios of about six large dimensionless numbers in physics. Dirac’s LNH postulates that these numerical coincidences reflect a deeper set of law-like relations, pointing to a revolutionary theory of cosmology. This led to substantial work, including the development of Dirac’s later [1969/74] cosmology, and other alternative cosmologies, such (...) as the Brans-Dicke modification of GTR, and to extensive empirical tests. We may refer to the generic hypothesis of “Large Number Relations” (LNR’s), as the proposal that there are lawlike relations of some kind between the dimensionless numbers, not necessarily those proposed in Dirac’s early LNH. Such relations would have a profound effect on our concepts of physics, but they remain shrouded in mystery. Although Dirac’s specific proposals for LNR theories have been largely rejected, the subject retains interest, especially among cosmologists seeking to test possible variations in fundamental constants, and to explain dark energy or the cosmological constant. In the first two sections here we briefly summarize the basic concepts of LNR’s. We then introduce an alternative LNR theory, using a systematic formalism to express variable transformations between conventional measurement variables and the true variables of the theory. We demonstrate some consistency results and review the evidence for changes in the gravitational constant G. The theory adopted in the strongest tests of Ġ/G, by the Lunar Laser Ranging (LLR) experiments, assumes: Ġ/G = 3(dr/dt)/r – 2(dP/dt)/P – (dm/dt)/m, as a fundamental relationship. Experimental measurements show the RHS to be close to zero, so it is inferred that significant changes in G are ruled out. However when the relation is derived in our alternative theory it gives: Ġ/G = 3(dr/dt)/r – 2(dP/dt)/P – (dm/dt)/m – (dR/dt)/R. The extra final term (which is the Hubble constant) is not taken into account in conventional derivations. This means the LLR experiments are consistent with our LNR theory (and others), and they do not really test for a changing value of G at all. This failure to transform predictions of LNR theories correctly is a serious conceptual flaw in current experiment and theory. (shrink)

Gödel’s incompleteness applies to any system with recursively enumerable axioms and rules of inference. Chaitin’s approach to Gödel’s incompleteness relates the incompleteness to the amount of information contained in the axioms. Zurek’s quantum Darwinism attempts the physical description of the universe using information as one of its major components. The capacity of quantum Darwinism to describe quantum measurement in great detail without requiring ad-hoc non-unitary evolution makes it a good candidate for describing the transition from quantum to classical. A baby-universe (...) diffusion model of cosmic inflation is analyzed using quantum Darwinism. In this model cosmic inflation can be approximated as Brownian motion of a quantum field, and quantum Darwinism implies that molecular interaction during Brownian motion will make the quantum field decohere. The quantum Darwinism approach to decoherence in the baby-universe cosmic-inflation model yields the decoherence times of the baby-universes. The result is the equation relating the baby-universe’s decoherence time with the Hubble parameter, and that the decoherence time is considerably shorter than the cosmic inflation period. (shrink)

The aim of this essay is to introduce philosophers of science to some recent philosophical discussions of the nature and origin of the direction of time. The essay is organized around books by Hans Reichenbach, Paul Horwich, and Huw Price. I outline their major arguments and treat certain critical points in detail. I speculate at the end about the ways in which the subject may continue to develop and in which it may connect with other areas of philosophy.

The papers in this volume reflect much of the current unease of a world that perceives itself once more at the edge of chaos. The authors present different vistas of that experience and their inherent dialectic, expressed in numerous and ceaseless conflicts between ordering and disordering processes. They can be read as comments on the ongoing processes that lead toward greater complexity.

Branching-time temporal logics have proved to be an extraordinarily successful tool in the formal specification and verification of distributed systems. Much of their success stems from the tractability of the model checking problem for the branching time logic CTL, which has made it possible to implement tools that allow designers to automatically verify that systems satisfy requirements expressed in CTL. Recently, CTL was generalised by Alur, Henzinger, and Kupferman in a logic known as Alternating-time Temporal Logic (ATL). (...) The key insight in ATL is that the path quantifiers of CTL could be replaced by cooperation modalities, of the form , where is a set of agents. The intended interpretation of an ATL formula is that the agents can cooperate to ensure that holds (equivalently, that have a winning strategy for ). In this paper, we extend ATL with knowledge modalities, of the kind made popular in the work of Fagin, Halpern, Moses, Vardi and colleagues. Combining these knowledge modalities with ATL, it becomes possible to express such properties as group can cooperate to bring about iff it is common knowledge in that . The resulting logic — Alternating-time Temporal Epistemic Logic (ATEL) — shares the tractability of model checking with its ATL parent, and is a succinct and expressive language for reasoning about game-like multiagent systems. (shrink)

While today there is much discussion about the ethics of artificial intelligence, less work has been done on the philosophical nature of AI. Drawing on Bergson and Ricoeur, this paper proposes to use the concepts of time, process, and narrative to conceptualize AI and its normatively relevant impact on human lives and society. Distinguishing between a number of different ways in which AI and time are related, the paper explores what it means to understand AI as narrative, as (...) process, or as the emergent outcome of processes and narratives. It pays particular attention to what it calls the “narrator” and “time machine” roles of AI and the normative implications of these roles. It argues that AI processes and narratives shape our time and link past, present, and future in particular ways that are ethically and politically significant. (shrink)

Arina Oriekhova's interview with Professor Serhii Secundant, devoted to Leibniz's concept of time and space, the peculiarities of Michael Fatch's interpretation of this concept, and various historico-philosophical approaches to understanding Leibniz's philosophy as a whole.

We propose a solution to the problem of time for systems with a single global Hamiltonian constraint. Our solution stems from the observation that, for these theories, conventional gauge theory methods fail to capture the full classical dynamics of the system and must therefore be deemed inappropriate. We propose a new strategy for consistently quantizing systems with a relational notion of time that does capture the full classical dynamics of the system and allows for evolution parametrized by an (...) equitable internal clock. This proposal contains the minimal temporal structure necessary to retain the ordering of events required to describe classical evolution. In the context of shape dynamics (an equivalent formulation of general relativity that is locally scale invariant and free of the local problem of time) our proposal can be shown to constitute a natural methodology for describing dynamical evolution in quantum gravity and to lead to a quantum theory analogous to the Dirac quantization of unimodular gravity. (shrink)

I argue that our experience of time supports the B-Theory of time and not the A-Theory of time. We do not experience pastness, presentness, and futurity as mind-independent properties of events. My method in supporting this experiential claim is to show that our experience of presentness is like our experience of hereness--in neither case are we aware of a mind-independent property over and above the events or objects to which we ascribe the presentness or hereness.

The first part (“Is there a future?”), discusses the idea of the future in the context of Carl Schmitt’s vision for the spatial revolutions of modernity, and then the idea of Anthropocene, as a synonym for an environmental crisis endangering the very survival of humankind. From this point of view, the conquest of space and the colonization of Mars at the center of futuristic and technocratic visions appear to be an attempt to escape from human responsibilities on Earth. The second (...) part (“AI and other hyperobjects”) discusses the extent of intellectual hubris expressed in computation, AI (Garvin Minsky e Ray Kurzweil), and the philosophy of computing and information (Eric Fredkin), involved in the elaboration of new theoretical assessments on the ultimate nature of reality. Their vision is then contrasted and made to interact with that of philosopher Timothy Morton. He has taken the perspective of global warming and the possibility of ecological catastrophe seriously, avoiding all the futuristic enthusiasms and instead emphasizing the radical nature of the transformations that humans experience in the present. In this perspective, AI becomes one of the “hyperobjects,” like the Internet or climate change, in which humans are immersed. Morton’s hyperobjects delineate an uncanny view of the future; this uncanniness is not related to the supernatural but to the environment. The third section (“More-than-human-humanism”) further reflects on the “uncanniness” that human perceive in the encounters with the manifestations of hyperobjects. It also seeks to understand the human position in the face of the radical technological transformations induced by cybernetics and AI. This section discusses Anti-humanism, Transhumanism, and Posthumanism within the broader category of more-than-human thought, which seems to be a more appropriate term to clarify the possible misunderstandings induced by the word “posthuman” and “transhuman.” The central question is not to empower (Transhumanism) or disempower (Posthumanism) humans, but to see them in relation to what is not human, including other animals, the environment, and the machine. The analysis considers the works of Cary Wolfe, Jane Bennet, Bryant Levi, among others, and introduces ethical debates on cyborgs, robots, and Autonomous weapons systems (AWS). The fourth section (“Ethical Perspectives”) continues this inquiry, concentrating on the non-standard ethical theories of Luciano Floridi (Computer and Information Ethics) and David Gunkel (The question of the Machine). It examines the opportunity and feasibility of including in the discussion on the ethics of our time - characterized by the pervasiveness of AI - the notions of consciousness as theorized by Emmanuel Levinas’s Humanism of the Other and Paul Ricoeur’s Oneself as Another. Finally, the last section (“The time of the end?”) reflects on how the hyperobject, Anthropocene, re-establishes a sense of limits in human history and confirms the special responsibility of human beings, and supports the need for a more-than-human-humanism. The latter, in other words, means intertwining ourselves with a unique ecosystem which cannot be overlooked and which restores meaning to our relationship with the past, present, and future. The awareness of the current challenges of technology can and must express itself in different forms of resistance to the adverse effects of AI in our lives. The ethical approach based on the persisting role of human consciousness is essential, but it must be coupled with human decision-making and political action. (shrink)