Recent developments in quantum theory have focused attention on fundamental questions, in particular on whether it might be necessary to modify quantum mechanics to reconcile quantum gravity and general relativity. This book is based on a conference held in Oxford in the spring of 1984 to discuss quantum gravity. It brings together contributors who examine different aspects of the problem, including the experimental support for quantum mechanics, its strange and apparently paradoxical features, its underlying philosophy, and possible modifications to the (...) theory. (shrink)

[opening paragraph] -- Clark: The Emperor's New Mind was such a massive and detailed work, it seems extraordinary to me that within five years you have written another book on consciousness.

In this paper I offer a limited defence of “fairness” or “fair play” arguments for political obligation by focussing on one important critique of such arguments, that offered by A. John Simmons. I isolate Simmons's concentration on the idea of “accepting” benefits and argue that, among other difficulties, his criteria for when we can be said to accept a benefit from our political communities are too restrictive. While the scope of the discussion is narrow, I try to sketch ways in (...) which the failings of Simmons's critique are symptomatic of deeper problems with his libertarian approach. S. Afr. J. Philos. Vol.23(3) 2004: 282-291. (shrink)

Artificial Neural Networks have reached “grandmaster” and even “super-human” performance across a variety of games, from those involving perfect information, such as Go, to those involving imperfect information, such as “Starcraft”. Such technological developments from artificial intelligence (AI) labs have ushered concomitant applications across the world of business, where an “AI” brand-tag is quickly becoming ubiquitous. A corollary of such widespread commercial deployment is that when AI gets things wrong—an autonomous vehicle crashes, a chatbot exhibits “racist” behavior, automated credit-scoring processes (...) “discriminate” on gender, etc.—there are often significant financial, legal, and brand consequences, and the incident becomes major news. As Judea Pearl sees it, the underlying reason for such mistakes is that “... all the impressive achievements of deep learning amount to just curve fitting.” The key, as Pearl suggests, is to replace “reasoning by association” with “causal reasoning” —the ability to infer causes from observed phenomena. It is a point that was echoed by Gary Marcus and Ernest Davis in a recent piece for theNew York Times: “we need to stop building computer systems that merely get better and better at detecting statistical patterns in data sets—often using an approach known as ‘Deep Learning’—and start building computer systems that from the moment of their assembly innately grasp three basic concepts: time, space, and causality.” In this paper, foregrounding what in 1949 Gilbert Ryle termed “a category mistake”, I will offer an alternative explanation for AI errors; it is not so much that AI machinery cannot “grasp” causality, but that AI machinery (qua computation) cannot understand anything at all. (shrink)

Lanczos, C. Einstein's path from special to general relativity.--Balazs, N. L. The acceptability of physical theories: Poincaré versus Einstein.--Ellis, G. F. R. Global and non-global problems in cosmology, by G. F. R. Ellis and D. W. Sciama.--Ehlers, J. The geometry of free fall and light propagation, by J. Ehlers, F. A. E. Pirani and A. Schild.--Trautman, A. Invariance of Lagrangian systems.--Penrose, R. The geometry of impulsive gravitational waves.--Exact solutions of the Einstein-Maxwell equations for an accelerated charge.--Taub, A. H. Plane-symmetric (...) similarity solutions for self-gravitating fluids.--Robinson, I. Equations of motion in the linear approximation, by I. Robinson and J. R. Robinson.--Florides, P. W. Rotating bodies in general relativity.--Chandrasekhar, S. A limiting case of relativistic equilibrium.--Israel, W. The relativistic Boltzmann equation.--Thompson, W. B. The self-consistent test-particle approach to relativistic kinetic theory. (shrink)

The quantum measurement problem and various unsuccessful attempts to resolve it are reviewed. A suggestion by Diosi and Penrose for the half-life of the quantum superposition of two Newtonian gravitational fields is generalized to an arbitrary quantum superposition of relativistic, but weak, gravitational fields. The nature of the “collapse” process of the wave function is examined.

[opening paragraph]: As some of us in the brain and cognitive sciences struggled in relative obscurity over the last two decades to gain some sound empirical understanding of conscious experience, a succession of celebrated philosophers and scientists told us that our work was doomed to failure. They expended extraordinary ingenuity trying to prove their case, at least as much as those of us toiling in the trenches devoted to the job of gaining a little bit of clarity. Fortunately, `impossibility proofs' (...) of this kind tend to have a short half-life. They succeed each other year after year; in the same way that impossibility proofs were flourished triumphantly by critics to demonstrate, once and forever, that we could never understand planetary motion, biological evolution, quantum mechanics -- or whatever next topic science, in its Brobdignagian march, was threatening to clarify. Arthur C. Clarke once proposed a law stating that for every major advance in knowledge one can find at least one celebrated scientist who was able to `prove', shortly before it was achieved, that it could not be done. In the case of conscious experience the quest to prove impossibility is especially passionate, as if a reasonable scientific approach to human experience were the enemy of all that is good and decent. (shrink)

In his stimulating book SHADOWS OF THE MIND, Roger Penrose presents arguments, based on Gödel's theorem, for the conclusion that human thought is uncomputable. There are actually two separate arguments in Penrose's book. The second has been widely ignored, but seems to me to be much more interesting and novel than the first. I will address both forms of the argument in some detail. Toward the end, I will also comment on Penrose's proposals for a "new science (...) of consciousness". (shrink)

The connection between quantum physics and the mind has been debated for almost a hundred years. There are several proposals as to how quantum effects might be relevant to understanding consciousness, including von Neumann’s Consciousness Causes Collapse interpretation (CCC), Penrose’s Orchestrated objective reduction (Orch OR), Atmanspacher quantum emergence theory, or Vitiello’s field theory. In this paper, we examine the CCC, in particular Stapp’s theory of interaction of mind and matter, and discuss how this imposes constraints to possible brain structures. (...) We then argue that those constraints may allow us to identify a possible locus of the interaction between mind and matter, if CCC is true. (shrink)

A theoretical approach relying on quantum computation in microtubules within neurons can potentially resolve the enigmatic features of visual consciousness, but raises other questions. For example, how can delicate quantum states, which in the technological realm demand extreme cold and isolation to avoid environmental ‘decoherence’, manage to survive in the warm, wet brain? And if such states could survive within neuronal cell interiors, how could quantum states grow to encompass the whole brain? We present a physiological model for visual consciousness (...) that can accommodate brain-wide quantum computation according to the Penrose–Hameroff ‘Orch OR’ model. In this view, visual consciousness occurs as a series of several-hundred-millisecond epochs, each comprising ‘crescendo sequences’ of quantum computations occurring at ∼40 Hz. (shrink)

In [1] it is claimed that, based on radiation emission measurements described in [2], a certain “variant” of the Orch OR theory has been refuted. I agree with this claim. However, the significance of this result for Orch OR per se is unclear. After all, the refuted “variant” was never advocated by anyone, and it contradicts the views of Hameroff and Penrose (hereafter: HP) who invented Orch OR [3]. My aim is to get clear on this situation. I argue (...) that it is indeed reasonable to speak of “variants” here. Orch OR is not a complete model of reality but a work in progress. At its core, it claims that wavefunction collapse is a real physical event that has something to do with gravity (“OR”) and that consciousness depends on orchestrated collapses in microtubules (“Orch”). There are many ways one could make these base ideas precise hence many “variants”. Furthermore, the ways that HP aim to make these ideas precise are radical and incomplete. If they don’t work out, Orch OR will need to fall back on another variant. Thus, I believe the significance of [1-2] for Orch OR is that it cuts out a small class of possible variants and leaves behind questions and challenges for the rest, including the variant preferred by HP. (shrink)

I argue that a dual-aspect theory of consciousness, associated with a particular class of quantum states, can provide a consistent account of consciousness. I illustrate this with the use of coherent states as this class. The proposal meets Chalmers 'requirements of allowing a structural correspondence between consciousness and its physical correlate. It provides a means for consciousness to have an effect on the world (it is not an epiphenomenon, and can thus be selected by evolution) in a way that supplements (...) and completes conventional physics, rather than interfering with it. I draw on the work of Hameroff and Penrose to explain the consistency of this proposal with decoherence, while adding details to this work. The proposal is open to extensive further research at both theoretical and experimental levels. (shrink)

This volume contains a selection of Professor Uzawa's important contributions to mathematical economics. Subjects covered by these nineteen essays include consumption, production, equilibrium, capital, growth, planning, international trade, and the theory of social overhead capital. Written in the 1960s and early 1970s, the papers form a basis upon which economic theory has developed over the last twenty years. The collection includes some of Uzawa's classic contributions, such as 'Preference and Rational Choice in the Theory of Consumption', 'Time Preference, the Consumption (...) Function, and Optimum Asset Holdings', 'Neutral Inventions and the Stability of Growth Equilibrium', 'On a Two-Sector Model of Economic Growth', 'Time Preference and the Penrose Effect in a Two-Class Model of Economic Growth', and 'On the Economics of Social Overhead Capital'. The collection will be useful not only in understanding the nature of the development in economic theory today, but also in reflecting upon the direction toward which economic theory will be advancing in the future. (shrink)

Where does the road to reality lie? This fundamental question is addressed in this collection of essays by physicists and philosophers, inspired by the original ideas of Sir Roger Penrose, the English mathematical physicist and philosopher of science. The topics range from black holes and quantum information to the very nature of mathematical cognition itself. *** Librarians: ebook available on ProQuest and EBSCO [Subject: Philosophy, Physics, Mathematics, Cosmology].

An important contribution to the foundations of probability theory, statistics and statistical physics has been made by E. T. Jaynes. The recent publication of his collected works provides an appropriate opportunity to attempt an assessment of this contribution. * Review of E. T. JAYNES (1983): Papers on Probability, Statistics and Statistical Physics. Edited by R. D. Rosenkrantz. D. Reidel Publishing Company. US $49.50. Pp. xxiv + 434. We are grateful to Harvey Brown, Kenneth Denbigh, Udi Makov and Oliver Penrose (...) for their valuable criticisms of this paper. (shrink)

Experiments are described, using electroencephalography (EEG) and simple tests of performance, which support the hypothesis that collapse of a quantum field is of importance to the functioning of the brain. The theoretical basis of our experiments is derived from Penrose (1989) who suggested that conscious decision-making is a manifestation of the outcome of quantum computation in the brain involving collapse of some relevant wave function. He also proposed that collapse of any wave function depends on a gravitational criterion. As (...) different brain areas are known to subserve different functions, we argue that `Penrose collapse' must occur in a particular brain area when performing a task that uses it. Further, taking an EEG from the area should amplify the gravitational prerequisite for collapse, so affecting task performance. There are no non-quantum theories which could lead one to expect that taking an EEG could directly affect task performance by subjects. The results of both pilot and main experiments indicated that task performance was indeed influenced by taking an EEG from relevant brain areas. Control experiments suggested that the influence was quantum mechanical in origin, and was not due to any experimental artefact. The results are statistically significant and merit attempts at replication in an independent laboratory, preferably with more sophisticated equipment than was available to us. (shrink)

Roger Penrose is justly famous for his work in physics and mathematics but he is _notorious_ for his endorsement of the Gödel argument (see his 1989, 1994, 1997). This argument, first advanced by J. R. Lucas (in 1961), attempts to show that Gödel’s (first) incompleteness theorem can be seen to reveal that the human mind transcends all algorithmic models of it¹. Penrose's version of the argument has been seen to fall victim to the original objections raised against Lucas (...) (see Boolos (1990) and for a particularly intemperate review, Putnam (1994)). Yet I believe that more can and should be said about the argument. Only a brief review is necessary here although I wish to present the argument in a somewhat peculiar form. (shrink)

It is commonly agreed that the well-known Lucas-Penrose arguments and even Penrose's 'new argument' in [Penrose, R. (1994): Shadows of the Mind, Oxford University Press] are inconclusive. It is, perhaps, less clear exactly why at least the latter is inconclusive. This note continues the discussion in [Lindström, P. (2001): Penrose's new argument, J. Philos. Logic 30, 241-250; Shapiro, S.(2003): Mechanism, truth, and Penrose's new argument, J. Philos. Logic 32, 19-42] and elsewhere of this question.

Having, as it is generally agreed, failed to destroy the computational conception of mind with the G\"{o}delian attack he articulated in his {\em The Emperor's New Mind}, Penrose has returned, armed with a more elaborate and more fastidious G\"{o}delian case, expressed in and 3 of his {\em Shadows of the Mind}. The core argument in these chapters is enthymematic, and when formalized, a remarkable number of technical glitches come to light. Over and above these defects, the argument, at best, (...) is an instance of either the fallacy of denying the antecedent, the fallacy of {\em petitio principii}, or the fallacy of equivocation. More recently, writing in response to his critics in the electronic journal {\em Psyche}, Penrose has offered a G\"{o}delian case designed to improve on the version presented in {\em SOTM}. But this version is yet again another failure. In falling prey to the errors we uncover, Penrose's new G\"{o}delian case is unmasked as the same confused refrain J.R. Lucas initiated 35 years ago. (shrink)

In his PhD thesis (1938) Turing introduced what he described as 'a new kind of machine'. He called these 'O-machines'. The present paper employs Turing's concept against a number of currently fashionable positions in the philosophy of mind.

Introduction 'Superstructuralism'. I coin the term to cover the whole field of Structuralists, Semioticians, Althusserian Marxists, ...

We examine physicists’ charge of ad hocness against the Higgs mechanism in the standard model of elementary particle physics. We argue that even though this charge never rested on a clear-cut and well-entrenched definition of “ad hoc”, it is based on conceptual and methodological assumptions and principles that are well-founded elements of the scientific practice of high-energy particle physics. We further evaluate the implications of the recent discovery of a Higgs-like particle at the CERN’s Large Hadron Collider for the charge (...) of ad hocness against the Higgs mechanism. (shrink)

Winner of the Wolf Prize for his contribution to our understanding of the universe, Penrose takes on the question of whether artificial intelligence will ever ...

In lieu of an abstract, here is a brief excerpt of the content:Why the Phenomenology Remains FoundationalRobert Harland (bio)Keywordspsychology, cognitive-behavioral therapy (CBT), phenomenology, psychiatry, depressionDemian Whiting in his paper criticizes an exclusively cognitive approach to the treatment of emotional problems. There is no doubt that the cognitive model of the mind has been recently in the ascendancy and therapies based on it are to be found in almost every subspecialty of psychiatry. Cognitive-behavioral therapy (CBT) in particular is "discovered" as (...) being effective in everything from posttraumatic stress disorder to psychosis. The heartland of the approach is and remains anxiety and depression, the two most common emotional states that psychiatrists and psychologists are asked to deal with. As Dr. Whiting describes, leaving aside the behavioral aspects, the basic principle is about eliciting and challenging distorted cognitions. Cognitive theory suggests that distorted cognitions are the cause of, the substance of, and the maintaining factors in most if not all depression and anxiety.The author accepts that in certain cases distorted cognitions lead to an experience that is represented contra to reality. He suggests that in certain circumstances a cognitive therapist could help a patient to reappraise the world they find themselves in and by gathering evidence with the therapist, to challenge these distortions. So in depression, a patient sees themselves as worthless and their therapist suggests they gather evidence that helps them form a more balanced perspective. The cognition "I am worthless" is shown empirically to be a distortion. Whiting argues, correctly in my opinion, for the limitation of this approach. In doing so he argues against a growing psychological hegemony, one that sees itself as developing evidence-based practice that should be applied (on the back of national guidelines) to many presentations before or exclusively of others such as medication or alternative psychotherapeutic approaches.Whatever the outcome in the clinic, as opposed to the randomized controlled trials, many clinicians and health care managers are attracted to CBT because of its pragmatic, short-term, problem- and consumer-orientated nature. It has an approach tailored for most disorders and therefore fits very well within the organization of modern mental health services. With this background, nonclinical readers may more readily appreciate the potential target of Dr. Whiting's critique.Whiting suggests three examples where eliciting cognitions can at best be seen as secondary [End Page 247] to the problem in hand: First, where a drug (e.g., alcohol) or state (e.g., tiredness) directly causes an emotion; second, where an emotion causes a mistaken understanding of a situation; and third, where the representation is accurate but the response defective (e.g., the pedophile in his article, or more routinely a person particularly sensitive to anxiety). The phenomenology, before the prism of analysis, is that in all three cases the patients find themselves in an emotional state where any putative cognitive etiology is at best post hoc and at worst tautological. Furthermore, as the author states, in the cases where accurate representations elicit the wrong kinds of emotions, the question why cannot be answered by referring back to the person's representations.To answer the question of why someone is particularly sensitive to anxiety or gets aroused by children, Dr. Whiting points to several possibilities that all impact on treatment: First, the influence of noncognitive desires and emotions; second, physical contamination; third, an idiosyncratic or abnormal constitution; and fourth, a defective emotional acculturation. In all these cases, suggesting that the patient's problems will be resolved through altering eliciting cognitions seems illogical.The paper then preempts two criticisms from the cognitive approach. The first again rightly expands that, if a higher order evaluative level is proposed, this in no way answers a noncognitive critique. Either the higher level of evaluation is simply an unnecessary (or unpredictable) cognitive confirmation of a negative (or positive) representation, or the evaluation is a cognitive foil for an emotional reaction that is simply not cognitive; when someone says they are worthless they are merely giving voice to their depressed emotional state. Second, that retreating to a position where the cognitive approach is used to challenge distorted representations that are secondary to, and yet maintain, an inappropriate emotion may have a role, but does not mean that... (shrink)