When the stored representation of the meaning of a stimulus is accessed through the processing of a sensory input it is maintained in an activated state for a certain amount of time that allows for further processing. This semantic activation is generally accompanied by conscious identification, which can be demonstrated by the ability of a person to perform discriminations on the basis of the meaning of the stimulus. The idea that a sensory input can give rise to semantic activation without (...) concomitant conscious identification was the central thesis of the controversial research in subliminal perception. Recently, new claims for the existence of such phenomena have arisen from studies in dichotic listening, parafoveal vision, and visual pattern masking. Because of the fundamental role played by these types of experiments in cognitive psychology, the new assertions have raised widespread interest. (shrink)

Can we make progress exploring consciousness? Or is it forever beyond human reach? In science we never know the ultimate outcome of the journey. We can only take whatever steps our current knowledge affords. This paper explores today's evidence from the viewpoint of Global Workspace theory. First, we ask what kind of evidence has the most direct bearing on the question. The answer given here is ‘contrastive analysis’ -- a set of paired comparisons between similar conscious and unconscious processes. This (...) body of evidence is already quite large, and constrains any possible theory . Because it involves both conscious and unconscious events, it deals directly with our own subjective experience, as anyone can tell by trying the demonstrations in this article. (shrink)

Although the mechanics of how the eye works are well understood, debate still exists as to how the complex machinery of the brain interprets neural impulses...

Vision, more than any other sense, dominates our mental life. Our visual experience is just so rich, so detailed, that we can hardly distinguish that experience from the world itself. Even when we just think about the world and don't look at it directly, we can't help but 'imagine' what it looks like. We think of 'seeing' as being a conscious activity--we direct our eyes, we choose what we look at, we register what we are seeing. The series of events (...) described in this book radically altered this attitude towards vision. This book describes one of the most extraordinary neurological cases of recent years--one that profoundly changed scientific views on consciousness. It is the story of Dee Fletcher--a woman recently blinded--who became the subject of a series of scientific studies. As events unfolded, Milner and Goodale found that Dee wasn't in fact blind--she just didn't know that she could see. Taking us on a journey into the unconscious brain, the two scientists who made this incredible discovery tell the amazing story of their work, and the surprising conclusion they were forced to reach. Written to be accessible to students and popular science readers, this book is a fascinating illustration of the power of the 'unconscious' mind. (shrink)

How can we disentangle the neural basis of phenomenal consciousness from the neural machinery of the cognitive access that underlies reports of phenomenal consciousness? We can see the problem in stark form if we ask how we could tell whether representations inside a Fodorian module are phenomenally conscious. The methodology would seem straightforward: find the neural natural kinds that are the basis of phenomenal consciousness in clear cases when subjects are completely confident and we have no reason to doubt their (...) authority, and look to see whether those neural natural kinds exist within Fodorian modules. But a puzzle arises: do we include the machinery underlying reportability within the neural natural kinds of the clear cases? If the answer is ‘Yes’, then there can be no phenomenally conscious representations in Fodorian modules. But how can we know if the answer is ‘Yes’? The suggested methodology requires an answer to the question it was supposed to answer! The paper argues for an abstract solution to the problem and exhibits a source of empirical data that is relevant, data that show that in a certain sense phenomenal consciousness overflows cognitive accessibility. The paper argues that we can find a neural realizer of this overflow if assume that the neural basis of phenomenal consciousness does not include the neural basis of cognitive accessibility and that this assumption is justified by the explanations it allows. (shrink)

This introductory chapter attempts to clarify the philosophical, empirical, and theoretical bases on which a cognitive neuroscience approach to consciousness can be founded. We isolate three major empirical observations that any theory of consciousness should incorporate, namely (1) a considerable amount of processing is possible without consciousness, (2) attention is a prerequisite of consciousness, and (3) consciousness is required for some specific cognitive tasks, including those that require durable information maintenance, novel combinations of operations, or the spontaneous generation of intentional (...) behavior. We then propose a theoretical framework that synthesizes those facts: the hypothesis of a global neuronal workspace. This framework postulates that, at any given time, many modular cerebral networks are active in parallel and process information in an unconscious manner. An information becomes conscious, however, if the neural population that represents it is mobilized by top-down attentional amplification into a brain-scale state of coherent activity that involves many neurons distributed throughout the brain. The long-distance connectivity of these `workspace neurons' can, when they are active for a minimal duration, make the information available to a variety of processes including perceptual categorization, long-term memorization, evaluation, and intentional action. We postulate that this global availability of information through the workspace is what we subjectively experience as a conscious state. A complete theory of consciousness should explain why some cognitive and cerebral representations can be permanently or temporarily inaccessible to consciousness, what is the range of possible conscious contents, how they map onto specific cerebral circuits, and whether a generic neuronal mechanism underlies all of them. We confront the workspace model with those issues and identify novel experimental predictions. Neurophysiological, anatomical, and brain-imaging data strongly argue for a major role of prefrontal cortex, anterior cingulate, and the areas that connect to them, in creating the postulated brain-scale workspace. (shrink)

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of (...) acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The out- side world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the gov- erning laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Sev- eral lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual “filling in,” visual stability despite eye movements, change blindness, sensory substitution, and color perception. (shrink)

1 Introduction 2 Perceptual Concepts 2.1 Perceptual Concepts are not Demonstrative 2.2 Perceptual Concepts as Stored Templates 2.3 Perceptual Semantics 2.4 Perceptually Derived Concepts 3 Phenomenal Concepts.

The paper discusses the utility of the notion of consciousness for the behavioural and brain sciences. It describes four distinctively different senses of 'conscious', and argues that to cope with the heterogeneous phenomena loosely indicated thereby, these sciences not only do not but should not discuss them in terms of 'consciousness'. It is thus suggested that 'the problem' allegedly posed to scientists by consciousness is unreal; one need neither adopt a realist stance with respect to it, nor include the term (...) and its cognates in the sciences' conceptual apparatus. The paper briefly examines Nagel's [1974] article, since this presents the strongest counter to the thesis proposed. (shrink)

In the final essay, the "intrinsic" nature of "qualia" is compared with the naively imagined "intrinsic value" of a dollar in ...

Knock-down refutations are rare in philosophy, and unambiguous self-refutations are even rarer, for obvious reasons, but sometimes we get lucky. Sometimes philosophers clutch an insupportable hypothesis to their bosoms and run headlong over the cliff edge. Then, like cartoon characters, they hang there in mid-air, until they notice what they have done and gravity takes over. Just such a boon is the philosophers' concept of a zombie, a strangely attractive notion that sums up, in one leaden lump, almost everything that (...) I think is wrong with current thinking about consciousness. Philosophers ought to have dropped the zombie like a hot potato, but since they persist in their embrace, this gives me a golden opportunity to focus attention on the most seductive error in current thinking. (shrink)

Beginning with Thomas Nagel, various philosophers have propsed setting conscious experience apart from all other problems of the mind as ‘the most difficult problem’. When critically examined, the basis for this proposal reveals itself to be unconvincing and counter-productive. Use of our current ignorance as a premise to determine what we can never discover is one common logical flaw. Use of ‘I-cannot-imagine’ arguments is a related flaw. When not much is known about a domain of phenomena, our inability to imagine (...) a mechanism is a rather uninteresting psychological fact about us, not an interesting metaphysical fact about the world. Rather than worrying too much about the meta-problem of whether or not consciousness is uniquely hard, I propose we get on with the task of seeing how far we get when we address neurobiologically the problems of mental phenomena. (shrink)

Consciousness fits uneasily into our conception of the natural world. On the most common conception of nature, the natural world is the physical world. But on the most common conception of consciousness, it is not easy to see how it could be part of the physical world. So it seems that to find a place for consciousness within the natural order, we must either revise our conception of consciousness, or revise our conception of nature. In twentieth-century philosophy, this dilemma is (...) posed most acutely in C. D. Broad’s The Mind and its Place in Nature . The phenomena of mind, for Broad, are the phenomena of consciousness. The central problem is that of locating mind with respect to the physical world. Broad’s exhaustive discussion of the problem culminates in a taxonomy of seventeen different views of the mental-physical relation.1 On Broad’s taxonomy, a view might see the mental as nonexistent , as reducible, as emergent, or as a basic property of a substance . The physical might be seen in one of the same four ways. So a four-by-four matrix of views results. At the end, three views are left standing: those on which mentality is an emergent characteristic of either a physical substance or a neutral substance, where in the latter case, the physical might be either emergent or delusive. (shrink)

The book is an extended study of the problem of consciousness. After setting up the problem, I argue that reductive explanation of consciousness is impossible , and that if one takes consciousness seriously, one has to go beyond a strict materialist framework. In the second half of the book, I move toward a positive theory of consciousness with fundamental laws linking the physical and the experiential in a systematic way. Finally, I use the ideas and arguments developed earlier to defend (...) a form of strong artificial intelligence and to analyze some problems in the foundations of quantum mechanics. (shrink)

This chapter contains sections titled: Introduction1 The Problem Arguments Against Materialism Type‐A Materialism Type‐B Materialism15 The Two‐Dimensional Argument Against Type‐B Materialism Type‐C Materialism Interlude Type‐D Dualism Type‐E Dualism Type‐F Monism Conclusions.

Dehaene and Naccache, Dennett and Jack and Shallice “see convergence coming from many different quarters on a version of the neuronal global workspace model†(Dennett, p. 1). (Boldface references are to papers in this volume.) On the contrary, even within this volume, there are commitments to very different perspectives on consciousness. And these differing perspectives are based on tacit differences in philosophical starting places that should be made explicit.  Indeed, it is not clear that different uses of “consciousness†and (...) “awareness†in this volume can be taken to refer to the same phenomenon. More specifically, I think there are three different concepts of consciousness in play in this issue. The global workspace model makes much more sense on one of these than on the others. (shrink)

During the last two decades, several different anti-physicalist arguments based on an epistemic or conceptual gap between the phenomenal and the physical have been proposed. The most promising physicalist line of defense in the face of these arguments – the Phenomenal Concept Strategy – is based on the idea that these epistemic and conceptual gaps can be explained by appeal to the nature of phenomenal concepts rather than the nature of non-physical phenomenal properties. Phenomenal concepts, on this proposal, involve unique (...) cognitive mechanisms, but none that could not be fully physically implemented. David Chalmers has recently presented a Master Argument to show that the Phenomenal Concept Strategy – not just this or that version of it, but any version of it – fails. Chalmers argues that the phenomenal concepts posited by such theories are either not physicalistically explicable, or they cannot explain our epistemic situation with regard to qualia. I argue that it is his Master Argument that fails. My claim is his argument does not provide any new reasons to reject the Phenomenal Concept Strategy. I also argue that, although the Phenomenal Concept Strategy is successful in showing that the physicalist is not rationally compelled to give up physicalism in the light of the anti-physicalist arguments, the anti-physicalist is not rationally compelled to give up the anti-physicalist argument in the light of the Phenomenal Concept Strategy either. (shrink)

Do you dream in color? If you answer Yes, how can you be sure? Before you recount your vivid memory of a dream featuring all the colors of the rainbow, consider that in the 1950s researchers found that most people reported dreaming in black and white. In the 1960s, when most movies were in color and more people had color television sets, the vast majority of reported dreams contained color. The most likely explanation for this, according to the philosopher Eric (...) Schwitzgebel, is not that exposure to black-and-white media made people misremember their dreams. It is that we simply don't know whether or not we dream in color. In Perplexities of Consciousness, Schwitzgebel examines various aspects of inner life and argues that we know very little about our stream of conscious experience. Drawing broadly from historical and recent philosophy and psychology to examine such topics as visual perspective, and the unreliability of introspection, Schwitzgebel finds us singularly inept in our judgments about conscious experience. (shrink)

Change blindness is the striking failure to see large changes that normally would be noticed easily. Over the past decade this phenomenon has greatly contributed to our understanding of attention, perception, and even consciousness. The surprising extent of change blindness explains its broad appeal, but its counterintuitive nature has also engendered confusions about the kinds of inferences that legitimately follow from it. Here we discuss the legitimate and the erroneous inferences that have been drawn, and offer a set of requirements (...) to help separate them. In doing so, we clarify the genuine contributions of change blindness research to our understanding of visual perception and awareness, and provide a glimpse of some ways in which change blindness might shape future research. (shrink)

It is widely agreed among contemporary philosophers of mind that science leaves us with an ‘explanatory gap’—that even after we know everything that science can tell us about the conscious mind and the brain, their relationship still remains mysterious. I argue that this agreed view is quite mistaken. The feeling of a ‘explanatory gap’ arises only because we cannot stop ourselves thinking about the mind–brain relation in a dualist way.

Do philosophers and ordinary people conceive of subjective experience in the same way? In this article, we argue that they do not and that the philosophical concept of phenomenal consciousness does not coincide with the folk conception. We first offer experimental support for the hypothesis that philosophers and ordinary people conceive of subjective experience in markedly different ways. We then explore experimentally the folk conception, proposing that for the folk, subjective experience is closely linked to valence. We conclude by considering (...) the implications of our findings for a central issue in the philosophy of mind, the hard problem of consciousness. (shrink)

This article is about the special, subjective concepts we apply to experience, called “phenomenal concepts”. They are of special interest in a number of ways. First, they refer to phenomenal experiences, and the qualitative character of those experiences whose metaphysical status is hotly debated. Conscious experience strike many philosophers as philosophically problematic and difficult to accommodate within a physicalistic metaphysics. Second, PCs are widely thought to be special and unique among concepts. The sense that there is something special about PCs (...) is very closely tied up with features of the epistemic access they afford to qualia. When we deploy phenomenal concepts introspectively to some phenomenally conscious experience as it occurs, we are said to be acquainted with our own conscious experiences. Accounts of PCs either have to explain the acquaintance relation, or acquaintance with our phenomenal experiences has to be denied. PCs have received much attention in recent philosophy of mind mainly because they figure in arguments for dualism and in physicalist responses to these arguments. The main topic of this article is to explore different accounts of phenomenal concepts and their role in recent debates over the metaphysical status of phenomenal consciousness. (shrink)

Descriptive accounts of the nature of explanation in neuroscience and the global goals of such explanation have recently proliferated in the philosophy of neuroscience and with them new understandings of the experimental practices of neuroscientists have emerged. In this paper, I consider two models of such practices; one that takes them to be reductive; another that takes them to be integrative. I investigate those areas of the neuroscience of learning and memory from which the examples used to substantiate these models (...) are culled, and argue that the multiplicity of experimental protocols used in these research areas presents specific challenges for both models. In my view, these challenges have been overlooked largely because philosophers have hitherto failed to pay sufficient attention to fundamental features of experimental practice. I demonstrate that when we do pay attention to such features, evidence for reduction and integrative unity in neuroscience is simply not borne out. I end by suggesting some new directions for the philosophy of neuroscience that pertain to taking a closer look at the nature of neuroscientific experiments. (shrink)

Large changes that occur in clear view of an observer can become difficult to notice if made during an eye movement, blink, or other such disturbance. This change blindness is consistent with the proposal that focused visual attention is necessary to see change, with a change becoming difficult to notice whenever conditions prevent attention from being automatically drawn to it. -/- It is shown here how the phenomenon of change blindness can provide new results on the nature of visual attention, (...) including estimates of its capacity and the extent to which it can bind visual properties into coherent descriptions. It is also shown how the resultant characterization of attention can in turn provide new insights into the role that it plays in the perception of scenes and events. (shrink)

s Gibson (1982) correctly points out, despite Quine’s brief flirtation with a “mitigated phenomenalism” (Gibson’s phrase) in the late 1940’s and early 1950’s, Quine’s ontology of 1953 (“On Mental Entities”) and beyond left no room for non-physical sensory objects or qualities. Anyone familiar with the contemporary neo-dualist qualia-freak-fest might wonder why Quinean lessons were insufficiently transmitted to the current generation.

Replication or even modelling of consciousness in machines requires some clarifications and refinements of our concept of consciousness. Design of, construction of, and interaction with artificial systems can itself assist in this conceptual development. We start with the tentative hypothesis that although the word “consciousness” has no well-defined meaning, it is used to refer to aspects of human and animal informationprocessing. We then argue that we can enhance our understanding of what these aspects might be by designing and building virtual-machine (...) architectures capturing various features of consciousness. This activity may in turn nurture the development of our concepts of consciousness, showing how an analysis based on information-processing virtual machines answers old philosophical puzzles as well enriching empirical theories. This process of developing and testing ideas by developing and testing designs leads to gradual refinement of many of our pre-theoretical concepts of mind, showing how they can be construed as implicitly “architecture-based” concepts. Understanding how humanlike robots with appropriate architectures are likely to feel puzzled about qualia may help us resolve those puzzles. The concept of “qualia” turns out to be an “architecture-based” concept, while individual qualia concepts are “architecture-driven”. (shrink)

The source of endless speculation and public curiosity, our scientific quest for the origins of human consciousness has expanded along with the technical capabilities of science itself and remains one of the key topics able to fire public as much as academic interest. Yet many problematic issues, identified in this important new book, remain unresolved. Focusing on a series of methodological difficulties swirling around consciousness research, the contributors to this volume suggest that ‘consciousness’ is, in fact, not a wholly viable (...) scientific concept. Supporting this ‘eliminativist‘ stance are assessments of the current theories and methods of consciousness science in their own terms, as well as applications of good scientific practice criteria from the philosophy of science. For example, the work identifies the central problem of the misuse of qualitative difference and dissociation paradigms, often deployed to identify measures of consciousness. It also examines the difficulties that attend the wide range of experimental protocols used to operationalise consciousness—and the implications this has on the findings of integrative approaches across behavioural and neurophysiological research. The work also explores the significant mismatch between the common intuitions about the content of consciousness, that motivate much of the current science, and the actual properties of the neural processes underlying sensory and cognitive phenomena. Even as it makes the negative eliminativist case, the strong empirical grounding in this volume also allows positive characterisations to be made about the products of the current science of consciousness, facilitating a re-identification of target phenomena and valid research questions for the mind sciences.​. (shrink)

Consciousness in experimental subjects is typically inferred from reports and other forms of voluntary behaviour. A wealth of everyday experience confirms that healthy subjects do not ordinarily behave in these ways unless they are conscious. Investigation of consciousness in vegetative state patients has been based on the search for neural evidence that such broad functional capacities are preserved in some vegetative state patients. We call this the standard approach. To date, the results of the standard approach have suggested that some (...) vegetative state patients might indeed be conscious, although they fall short of being demonstrative. The fact that some vegetative state patients show evidence of consciousness according to the standard approach is remarkable, for the standard approach to consciousness is rather conservative, and leaves open the pressing question of how to ascertain whether patients who fail such tests are conscious or not. We argue for a cluster-based ‘natural kind’ methodology that is adequate to that task, both as a replacement for the approach that currently informs research into the presence or absence of consciousness in vegetative state patients and as a methodology for the science of consciousness more generally. 1. Introduction2. The Vegetative State3. The Standard Approach4. The Natural Kind Methodology5. Is Consciousness a Special Case? 5.1 Is consciousness a natural kind?5.2 A special obstacle?6. Conclusion. (shrink)

We are material beings in a material world, but we are also beings who have experiences and feelings. How can these subjective states be just a matter of matter? To defend materialism, philosophical materialists have formulated what is sometimes called "the phenomenal-concept strategy," which holds that we possess a range of special concepts for classifying the subjective aspects of our experiences. In Consciousness Revisited, the philosopher Michael Tye, until now a proponent of the the phenomenal-concept strategy, argues that the strategy (...) is mistaken. A rejection of phenomenal concepts leaves the materialist with the task of finding some other strategy for defending materialism. Tye points to four major puzzles of consciousness that arise: How is it possible for Mary, in the famous thought experiment, to make a discovery when she leaves her black-and-white room? In what does the explanatory gap consist and how can it be bridged? How can the hard problem of consciousness be solved? How are zombies possible? Tye presents solutions to these puzzles -- solutions that relieve the pressure on the materialist created by the failure of the phenomenal-concept strategy. In doing so, he discusses and makes new proposals on a wide range of issues, including the nature of perceptual content, the conditions necessary for consciousness of a given object, the proper understanding of change blindness, the nature of phenomenal character and our awareness of it, whether we have privileged access to our own experiences, and, if we do, in what such access consists. (shrink)

Philosophers have lately seized upon Sperling's partial report technique and subsequent work on iconic memory in support of controversial claims about perceptual experience, in particular that phenomenology overflows cognitive access. Drawing on mounting evidence concerning postdictive perception, I offer an interpretation of Sperling's data in terms of cue-sensitive experience which fails to support any such claims. Arguments for overflow based on change-detection paradigms (e.g. Landman et al., 2003; Sligte et al., 2008) cannot be blocked in this way. However, such paradigms (...) are fundamentally different from Sperling's and, for rather different reasons, equally fail to establish controversial claims about perceptual experience. (shrink)

Most materialist responses to the zombie argument against materialism take either a “type-A” or “type-B” approach: they either deny the conceivability of zombies or accept their conceivability while denying their possibility. However, a “type-Q” materialist approach, inspired by Quinean suspicions about a priority and modal entailment, rejects the sharp line between empirical and conceptual truths needed for the traditional responses. In this paper, I develop a type-Q response to the zombie argument, one stressing the theory-laden nature of our conceivability and (...) possibility intuitions. I argue that our first-person access to the conscious mind systematically misleads us into thinking that the distinctive qualities of conscious experience—qualia—are nonfunctional. Qualia, I contend, are functional, even though they do not seem to be. To support my claim, I introduce the “meditations” of Rene Descartes’ zombie twin. This establishes the plausibility of an appearance/reality distinction for consciousness and it undermines various anti-materialist objections based on privileged first-person access. I conclude that the best overall theory posits an appearance/reality distinction for qualia, and this, for the type-Q materialist, is decisive. (shrink)