First-ever comprehensive introduction to the major new subject of quantum computing and quantum information.

R.I.G Hughes offers the first detailed and accessible analysis of the Hilbert-space models used in quantum theory and explains why they are so successful.

Jeffrey Barrett presents the most comprehensive study yet of a problem that has puzzled physicists and philosophers since the 1930s.

I have taken an experimental approach to this question. Freely voluntary acts are preceded by a specific electrical change in the brain that begins 550 ms before the act. Human subjects became aware of intention to act 350-400 ms after RP starts, but 200 ms. before the motor act. The volitional process is therefore initiated unconsciously. But the conscious function could still control the outcome; it can veto the act. Free will is therefore not excluded. These findings put constraints on (...) views of how free will may operate; it would not initiate a voluntary act but it could control performance of the act. The findings also affect views of guilt and responsibility. But the deeper question still remains: Are freely voluntary acts subject to macro-deterministic laws or can they appear without such constraints, non-determined by natural laws and ‘truly free'? I shall present an experimentalist view about these fundamental philosophical opposites. (shrink)

This comprehensive reference provides an exhaustive guide to current scholarship on the perennial problem of Free Will--perhaps the most hotly and voluminously debated of all philosophical problems. While reference is made throughout to the contributions of major thinkers of the past, the emphasis is on recent research. The essays, most of which are previously unpublished, combine the work of established scholars with younger thinkers who are beginning to make significant contributions. Taken as a whole, the Handbook provides an engaging and (...) accessible roadmap to the state of the art thinking on this enduring topic. (shrink)

I have taken an experimental approach to this question. Freely voluntary acts are preceded by a specific electrical change in the brain that begins 550 ms before the act. Human subjects became aware of intention to act 350-400 ms after RP starts, but 200 ms. before the motor act. The volitional process is therefore initiated unconsciously. But the conscious function could still control the outcome; it can veto the act. Free will is therefore not excluded. These findings put constraints on (...) views of how free will may operate; it would not initiate a voluntary act but it could control performance of the act. The findings also affect views of guilt and responsibility. But the deeper question still remains: Are freely voluntary acts subject to macro-deterministic laws or can they appear without such constraints, non-determined by natural laws and ‘truly free'? I shall present an experimentalist view about these fundamental philosophical opposites. (shrink)

In this book philosophers, physicists, psychologists, neurophysiologists, computer scientists, and others address this central topic in the growing discipline..

What is consciousness? Some philosophers have contended that ‘qualia’, or an experiential medium from which consciousness is derived, exists as a fundamental component of reality. Whitehead, for example, described the universe as being comprised of ‘occasions of experience’. To examine this possibility scientifically, the very nature of physical reality must be re-examined. We must come to terms with the physics of space-time -- as is described by Einstein's general theory of relativity -- and its relation to the fundamental theory of (...) matter -- as described by quantum theory. This leads us to employ a new physics of objective reduction: OR which appeals to a form of ‘quantum gravity’ to provide a useful description of fundamental processes at the quantum/classical borderline . Within the OR scheme, we consider that consciousness occurs if an appropriately organized system is able to develop and maintain quantum coherent superposition until a specific ‘objective’ criterion is reached; the coherent system then self-reduces . We contend that this type of objective self-collapse introduces non-computability, an essential feature of consciousness. OR is taken as an instantaneous event -- the climax of a self-organizing process in fundamental space-time -- and a candidate for a conscious Whitehead-like ‘occasion’ of experience. How could an OR process occur in the brain, be coupled to neural activities, and account for other features of consciousness? We nominate an OR process with the requisite characteristics to be occurring in cytoskeletal microtubules within the brain's neurons. (shrink)

How is mind related to matter? This ancient question in philosophy is rapidly becoming a core problem in science, perhaps the most important of all because it probes the essential nature of man himself. The origin of the problem is a conflict between the mechanical conception of human beings that arises from the precepts of classical physical theory and the very different idea that arises from our intuition: the former reduces each of us to an automaton, while the latter allows (...) our thoughts to guide our actions. The dominant contemporary approaches to the problem attempt to resolve this conflict by clinging to the classical concepts, and trying to explain away our misleading intuition. But a detailed argument given here shows why, in a scientific approach to this problem, it is necessary to use the more basic principles of quantum physics, which bring the observer into the dynamics, rather than to accept classical precepts that are profoundly incorrect precisely at the crucial point of the role of human consciousness in the dynamics of human brains. Adherence to the quantum principles yields a dynamical theory of the mind/brain/body system that is in close accord with our intuitive idea of what we are. In particular, the need for a self-observing quantum system to pose certain questions creates a causal opening that allows mind/brain dynamics to have three distinguishable but interlocked causal processes, one micro-local, one stochastic, and the third experiential. Passing to the classical limit in which the critical difference between zero and the finite actual value of Planck's constant is ignored not only eliminates the chemical processes that are absolutely crucial to the functioning of actual brains, it simultaneously blinds the resulting theoretical construct to the physical fine structure wherein the effect of mind on matter lies: the use of this limit in this context is totally unjustified from a physics perspective. (shrink)

Orthodox Copenhagen quantum theory renounces the quest to understand the reality in which we are imbedded, and settles for practical rules describing connections between our observations. Many physicist have regarded this renunciation of our effort describe nature herself as premature, and John von Neumann reformulated quantum theory as a theory of an evolving objective universe interacting with human consciousness. This interaction is associated both in Copenhagen quantum theory and in von Neumann quantum theory with a sudden change that brings the (...) objective physical state of a system in line with a subjectively felt psychical reality. The objective physical state is thereby converted from a material substrate to an informational and dispositional substrate that carries both the information incorporated into it by the psychical realities, and certain dispositions for the occurrence of future psychical realities. The present work examines and proposes solutions to two problems that have appeared to block the development of this conception of nature. The first problem is how to reconcile this theory with the principles of relativistic quantum field theory; the second problem is to understand whether, strictly within quantum theory, a person's mind can affect the activities of his brain, and if so how. Solving the first problem involves resolving a certain non-locality question. The proposed solution to the second problem is based on a postulated connection between effort, attention, and the quantum Zeno effect. This solution explains on the basic of quantum physics a large amount of heretofore unexplained data amassed by psychologists. (shrink)

It is argued that the principles of classical physics are inimical to the development of a satisfactory science of consciousness The problem is that insofar as the classical principles are valid consciousness can have no e ect on the behavior and hence on the survival prospects of the organisms in which it inheres Thus within the classical framework it is not possible to explain in natural terms the development of consciousness to the high level form found in human beings In (...) quantum theory on the other hand consciousness can be dynamically e cacious quantum the ory does allows consciousness to in uence behavior and thence to evolve in accordance with the principles of natural selection However this evo lutionary requirement places important constraints upon the details of the formulation of the quantum dynamical principles.. (shrink)

In this book the author has collected a number of his important works and added an extensive commentary relating his ideas to those of other prominentnames in the consciousness debate. The view presented here is that of a convinced dualist who challenges in a lively and humorous way the prevailing materialist "doctrines" of many recent works. Also included is a new attempt to explain mind-brain interaction via a quantum process affecting the release of neurotransmitters. John Eccles received a knighthood in (...) 1958 and was awarded the Nobel Prize for Medicine/Physiology in 1963. He has numerous other awards honouring his major contributions to neurophysiology. (shrink)

I will argue that emergence is an empirically plausible and unique philosophical/ scientific framework for bridging the ontological gap and the explanatory gap with respect to phenomenal consciousness. On my view the ontological gap is the gap between fundamental ingredients/parts of reality that are not conscious and beings/wholes that are conscious. The explanatory gap is the current lack of a philosophical/scientific theory that explains how non-conscious parts can become conscious wholes. Both gaps are of course conceptual as well as empirical (...) in nature. Section I will be devoted to these issues as well as providing other general criteria for an account of consciousness. In section II, different types of emergence will be defined in the context of a more general taxonomy of reduction and emergence. Emergentism about consciousness becomes much more plausible when we see that the ancient ‘atomism’ that drives physicalism on one end, and fundamental property dualism on the other, is probably false. Backing up this claim will be the primary burden of section III. In section IV I will conjecture that phenomenal consciousness is mereologically and perhaps nomologically emergent from neurochemical/ quantum processes, just as many other properties are so emergent. In section V I defend my view of emergence against the objections that: it cannot bridge the explanatory/ontological gap between matter and consciousness and it cannot account for the causal efficacy of consciousness in itself. Finally, in section VI, there is speculation about where all of this might take us in the future. (shrink)

This work examines whether the environmentally-induced decoherence approach in quantum mechanics brings us any closer to solving the measurement problem, and whether it contributes to the elimination of subjectivism in quantum theory. A distinction is made between ,collapse, and ,decoherence,, so that an explanation for decoherence does not imply an explanation for collapse. After an overview of the measurement problem and of the open-systems paradigm, we argue that taking a partial trace is equivalent to applying the projection postulate. A criticism (...) of Zurek's decoherence approach to measurements is also made, based on the restriction that he must impose on the interaction between apparatus and environment. We then analyze the element of subjectivity involved in establishing the boundary between system and environment, and criticize the incorporation of Everett's branching of memory records into the decoherence research program. Sticking to this program, we end by sketching a proposal for ‘environmentally-induced collapse’. (shrink)

It is emphasized that a many-worlds interpretation of quantum theory exists only to the extent that the associated basis problem is solved. The core basis problem is that the robust enduring states specified by environmental decoherence effects are essentially Gaussian wave packets that form continua of non-orthogonal states. Hence they are not a discrete set of orthogonal basis states to which finite probabilities can be assigned by the usual rules. The natural way to get an orthogonal basis without going outside (...) the Schroedinger dynamics is to use the eigenstates of the reduced density matrix, and this idea is the basis of some recent attempts by many-worlds proponents to solve the basis problem. But these eigenstates do not enjoy the locality and quasi-classicality properties of the states defined by environmental decoherence effects, and hence are not satisfactory preferred basis states. This core problem is obscured by approaches that treat the universe as a quantum computer, but it needs to be addressed and resolved before a many-worlds-type interpretation can be said to exist. (shrink)

[opening paragraph]: In his keynote paper David Chalmers defines ‘the hard problem’ by posing certain ‘Why’ questions about consciousness? Such questions must be posed within an appropriate setting. The way of science is to try to deduce the answer to many such questions from a few well defined assumptions. Much about nature can be explained in terms of the principles of classical mechanics. The assumptions, in this explanatory scheme, are that the world is composed exclusively of particles and fields governed (...) by specified mathematical laws that refer neither to any individual person, nor to anyone’s experiences. These physical laws are supposed to be such that particles and fields, acting in concert, can form causally efficacious real functional entities such as driveshafts and propellers. Similarly, surges of electrical and mechanical activity in appropriately designed material substrates, composed of particles and fields acting in concert, could implement, in the world of matter, complex functional structures and long sequences of logical operations. Thus it is conceivable that all of our behaviour, and all of the internal processing that occurs in our bodies and brains could be deduced, at least in principle, from the principles of classical mechanics and appropriate boundary conditions. -/- Contents: 1. Introduction: Philosophical Setting 2. Quantum Model of the Mind/Brain 3. Person and Self 4. Meeting Baars's Criteria for Consciousness 5. Qualia 6. Free-Will. (shrink)

Several errors in Stapp's interpretation of quantum mechanics and its application to mental causation (Henry P. Stapp, “Quantum theory and the role of mind in nature,” Foundations of Physics 31, 1465–1499 (2001)) are pointed out. An interpretation of (standard) quantum mechanics that avoids these errors is presented.

Quantum theory can be regarded as a rationally coherent theory of the interaction of mind and matter and it allows our conscious thoughts to play a causally e cacious and necessary role in brain dynamics It therefore provides a natural basis created by scientists for the science of consciousness As an illustration it is explained how the interaction of brain and consciousness can speed up brain processing and thereby enhance the survival prospects of conscious organisms as compared to similar organisms (...) that lack consciousness As a second illustration it is explained how within the quantum framework the consciously experi enced I directs the actions of a human being It is concluded that contemporary science already has an adequate framework for incorporat ing causally e cacious experiential events into the physical universe in a manner that puts the neural correlates of consciousness into the theory in a well de ned way explains in principle how the e ects of consciousness per se can enhance the survival prospects of organisms that possess it allows this survival e ect to feed into phylogenetic de velopment and explains how the consciously experienced I can direct human behaviour.. (shrink)

As the theory takes shape, it is applied to various experimental arrangements. Many of these are central to the discussion in the final part, which aims at making epistemological and ontological sense of the theory.

Comparatively recent advances in quantum measurement theory suggest that the decades-old flirtation between quantum mechanics and the philosophy of mind is about to end. Various approaches to what I have elsewhere dubbed 'interactive decoherence' promise to remove the conscious observer from the phenomenon of state vector reduction. The mechanisms whereby decoherence occurs suggest, on the one hand, that consciousness per se has no role in explaining the outcomes of quantum events and, on the other, that perhaps apart from questions about (...) the very lowest level properties of minds' instantiating hardware or wetware, the unique features of quantum mechanics are utterly irrelevant to the philosophy of mind. Here we explore a better account of interactive decoherence than I have offered elsewhere, make explicit the argument for irrelevance, and address some unanswered questions and an interesting objection against the formulation of decoherence on which our discussion is based. (shrink)

The existence of quantum correlates of consciousness (QCC) is doubtful from a scientific perspective. But even if their existence were verified, philosophical problems would remain. On the other hand, there could be more to QCC than meets the sceptic's eye: • QCC might be useful or even necessary for a better understanding of conscious experience or quantum physics or both. The main reasons for this are: the measurement problem (the nature of observation, the mysterious collapse of the wave function, etc.), (...) ostensibly shared features of quantum phenomena and conscious phenomena (e.g., complementarity, nonspatiality, acausality, spontaneity, and holism) and connections (ontology, causation, and knowledge), the qualia problem (subjectivity, explanatory gap etc.). But there are many problems, especially questions regarding realism and the nature and role of conscious observers; • QCC are conceptually challenging, because there are definitory problems and some crucial ontological and epistemological shortcomings. It is instructive to compare them with recent proposals for understanding neural correlates of consciousness (NCC). QCC are not sufficient for a quantum theory of mind, nor might they be necessary except perhaps in a very broad sense; • QCC are also empirically challenging. Nevertheless, QCC could be relevant and important for the mindbody problem: QCC might reveal features that are necessary at least for behavioral manifestations of human consciousness. But QCC are compatible with very different proposals for a solution of the mind-body problem. This seems to be both advantageous and detrimental. QCC restrict accounts of nomological identity. The discovery of QCC cannot establish a naturalistic theory of mind alone. But there are also problems with QCC in the framework of other ontologies. (shrink)