Sydney Shoemaker has attempted to save mental causation by a new account of realization. As Brian McLaughlin argues convincingly, the account has to face two major problems. First, realization does not guarantee entailment. So even if mental properties are realized by physical properties, they need not be entailed by them. This is the first, rather general metaphysical problem. A second problem, which relates more directly to mental causation is that Shoemaker must appeal to some kind of proportionality as a constraint (...) on causation in order to avoid redundant mental causation. I argue that, in addition, a “piling problem” arises, since causal powers seem to be bestowed twice. Then, I try to sketch an alternative view of the relation between causal powers and properties—a reductionist view—which fares better on some accounts. But it may have to face another and, perhaps, serious problem, the “problem of the natural unity of properties”. Finally, I will pose a question about the relation between causal powers and causation. (shrink)

Sydney Shoemaker has proposed a new definition of `realization’ and used it to try to explain how mental events can be causes within the framework of a non-reductive physicalism. I argue that it is not actually his notion of realization that is doing the work in his account of mental causation, but rather the assumption that certain physical properties entail mental properties that do not entail them. I also point out how his account relies on certain other controversial assumptions, including (...) analytical filler-functionalism for mental properties, and the assumption that causes must be proportional to their effects. I conclude by pointing out that Shoemaker has provided no explanation of why, on his view, certain physical properties entail mental properties. (shrink)

What makes us conscious? Many theories that attempt to answer this question have appeared recently in the context of widespread interest about consciousness in the cognitive neurosciences. Most of these proposals are formulated in terms of the information processing conducted by the brain. In this overview, we survey and contrast these models. We first delineate several notions of consciousness, addressing what it is that the various models are attempting to explain. Next, we describe a conceptual landscape that addresses how the (...) theories attempt to explain consciousness. We then situate each of several representative models in this landscape and indicate which aspect of consciousness they try to explain. We conclude that the search for the neural correlates of consciousness should be usefully complemented by a search for the computational correlates of consciousness. (shrink)

When he formulated the program of neurophenomenology, Francisco Varela suggested a balanced methodological dissolution of the hard problem of consciousness. I show that his dissolution is a paradigm which imposes itself onto seemingly opposite views, including materialist approaches. I also point out that Varela's revolutionary epistemological ideas are gaining wider acceptance as a side effect of a recent controversy between hermeneutists and eliminativists. Finally, I emphasize a structural parallel between the science of consciousness and the distinctive features of quantum mechanics. (...) This parallel, together with the former convergences, point towards the common origin of the main puzzles of both quantum mechanics and the philosophy of mind: neglect of the constitutive blindspot of objective knowledge. (shrink)

Most ?theories of consciousness? are based on vague speculations about the properties of conscious experience. We aim to provide a more solid basis for a science of consciousness. We argue that a theory of consciousness should provide an account of the very processes that allow us to acquire and use information about our own mental states ? the processes underlying introspection. This can be achieved through the construction of information processing models that can account for ?Type-C? processes. Type-C processes can (...) be specified experimentally by identifying paradigms in which awareness of the stimulus is necessary for an intentional action. The Shallice (1988b) framework is put forward as providing an initial account of Type-C processes, which can relate perceptual consciousness to consciously performed actions. Further, we suggest that this framework may be refined through the investigation of the functions of prefrontal cortex. The formulation of our approach requires us to consider fundamental conceptual and methodological issues associated with consciousness. The most significant of these issues concerns the scientific use of introspective evidence. We outline and justify a conservative methodological approach to the use of introspective evidence, with attention to the difficulties historically associated with its use in psychology. (shrink)

In recent years there has been an explosion of scientific work on consciousness in cognitive neuroscience, psychology, and other fields. It has become possible to think that we are moving toward a genuine scientific understanding of conscious experience. But what is the science of consciousness all about, and what form should such a science take? This chapter gives an overview of the agenda.

• An adequate conceptual framework is still needed to account for phenomena that (i) have a first-person, subjective-experiential or phenomenal character; (ii) are (usually) reportable and describable (in humans); and (iii) are neurobiologically realized.2 • The conscious subject plays an unavoidable epistemological role in characterizing the explanadum of consciousness through first-person descriptive reports. The experimentalist is then able to link first-person data and third-person data. Yet the generation of first-person data raises difficult epistemological issues about the relation of second-order awareness (...) or meta-awareness to first-order experience (e.g. (shrink)

Plain phenomenology explains theoretically salient mental or psychological distinctions with an appeal to their first-person applications. But it does not assume that warrant for such first-person judgment is derived from an explanatory theory constructed from the third-person perspective. Discussions in historical phenomenology can be treated as plain phenomenology. This is illustrated by a critical consideration of Brentano’s account of consciousness, drawing on some ideas in early Husserl. Dennett’s advocacy of heterophenomenology on the grounds of its supposed “neutrality” does not show (...) it is preferable to plain phenomenology. In fact the latter is more neutral in ways we ought to want, and permits a desirable use of first-person reflection that finds no place in the former. (shrink)

This talk, delivered at De l''autopoièse à la neurophénoménologie: un hommage à Francisco Varela; from autopoiesis to neurophenomenology: a tribute to Francisco Varela, June 18–20, at the Sorbonne in Paris, explicates several links between Varela''s neurophenomenology and his biological concept of autopoiesis.

This paper analyzes an explicit instantiation of the program of neurophenomenology in a neuroscientific protocol. Neurophenomenology takes seriously the importance of linking the scientific study of consciousness to the careful examination of experience with a specific first-person methodology. My first claim is that such strategy is a fruitful heuristic because it produces new data and illuminates their relation to subjective experience. My second claim is that the approach could open the door to a natural account of the structure of human (...) experience as it is mobilized in itself in such methodology. In this view, generative passages define the type of circulation which explicitly roots the active and disciplined insight the subject has about his/her experience in a biological emergent process. (shrink)

Introspective reports are used as sources of information about other minds, in both everyday life and science. Many scientists and philosophers consider this practice unjustified, while others have made the untestable assumption that introspection is a truthful method of private observation. I argue that neither skepticism nor faith concerning introspective reports are warranted. As an alternative, I consider our everyday, commonsensical reliance on each other’s introspective reports. When we hear people talk about their minds, we neither refuse to learn from (...) nor blindly accept what they say. Sometimes we accept what we are told, other times we reject it, and still other times we take the report, revise it in light of what we believe, then accept the modified version. Whatever we do, we have (implicit) reasons for it. In developing a sound methodology for the scientific use of introspective reports, we can take our commonsense treatment of introspective reports and make it more explicit and rigorous. We can discover what to infer from introspective reports in a way similar to how we do it every day, but with extra knowledge, methodological care, and precision. Sorting out the use of introspective reports as sources of data is going to be a painstaking, piecemeal task, but it promises to enhance our science of the mind and brain. (shrink)

To study conscious experience we must, to some extent, trust introspective reports; yet introspective reports often do not merit our trust. A century ago, E.B. Titchener advocated extensive introspective training as a means of resolving this difficulty. He describes many of his training techniques in his four-volume laboratory manual of 1901- 1905. This paper explores Titchener's laboratory manual with an eye to general questions about the prospects of introspective training for contemporary consciousness studies, with a focus on the following examples: (...) introspective knowledge of the combination tones that arise when a musical interval is played; the 'flight of colours' in the afterimage of a field of bright, broad- spectrum light; and the possibility of non-obvious visual illusions. Introspective training appears to have some merit, but also to involve significant hazards. (shrink)

The measurement of pain depends upon subjective reports, but we know very little about how research subjects or pain patients produce self-reported judgments. Representationalist assumptions dominate the field of pain research and lead to the critical conjecture that the person in pain examines the contents of consciousness before making a report about the sensory or affective magnitude of pain experience as well as about its nature. Most studies to date have investigated what Fechner termed “outer psychophysics”: the relationship between characteristics (...) of an external stimulus and the magnitude and nature of pain experience. In contrast, Fechner originally envisioned that “inner psychophysics” should investigate the relationship between physiological states and subjective experience. Despite the lack of established research tradition, inner psychophysics has a potential utility in elucidating underlying mechanisms for the production of phenomenal self-report. We illustrate this, using causal modeling analyses of the accuracy of self-reported pain ratings from our laboratory. We submit that the results are inconsistent with representationalist assumptions. Converging trends from several domains of consciousness studies seem to suggest that we need to abandon the unquestioned doctrine of representationalism and search for a more viable framework for understanding the generation of subjective self-report. (shrink)

Understanding the nature of pain depends, at least partly, on recognizing its subjectivity (thus, its first-person epistemology). This in turn requires using a first-person experiential method in addition to third-person experimental approaches to study it. This paper is an attempt to spell out what the former approach is and how it can be integrated with the latter. We start our discussion by examining some foundational issues raised by the use of introspection. We argue that such a first-person method in the (...) scientific study of pain (as in the study of any experience) is in fact indispensable by demonstrating that it has in fact been consistently used in conjunction with conventional third-person methodologies, and this for good reasons. We show that, contrary to what appears to be a widespread opinion, there is absolutely no reason to think that the use of such a first-person approach is scientifically and methodologically suspect. We distinguish between two uses of introspective methods in scientific experiments: one draws on the subjects’ introspective reports where any investigator has equal and objective access. The other is where the investigator becomes a subject of his own study and draws on the introspection of his own experiences. We give examples using and/or approximating both strategies that include studies of second pain summation and its relationship to neural activities, and brain imaging- psychophysical studies wherein sensory and affective qualities of pain are correlated with cerebral cortical activity. We explain what we call the experiential or phenomenological approach that has its origins in the work of Price and Barrell (1980). This approach capitalizes on the scientific prospects and benefits of using the introspection of the investigator. We distinguish between its vertical and horizontal applications. Finally, we conclude that integrating such an approach to standard third-person methodologies can only help us in having a fuller understanding of pain and of conscious experience in general. (shrink)

The preceding article by Marc Bekoff reveals much about our current understanding of animal self-consciousness and its implications. It also reveals how much more there is to be said and considered. This response briefly examines animal self-consciousness from scientific, moral, and theological perspectives. As Bekoff emphasizes, self-consciousness is not one thing but many. Consequently, our moral relationship to animals is not simply one based on a graded hierarchy of abilities. Furthermore, the complexity of animal self-awareness can serve as stimulus for (...) thinking about issues of theodicy and soteriology in a broader sense. (shrink)

In this paper a framework to study consciousness in animals is proposed which is based on a hierarchical organizational feedback model of the central nervous system, the separation of a given mental state into two components, i.e. an invariant part, and a variant part, which are separately related to the organization of the central nervous system, i.e. 'a neural network' and 'momentary active connections within the neural network determined by in- and output of this neural network' respectively, and phylogeny based (...) on the invariant part or the presence of a neural network. Consciousness is defined as a property of neural networks of self-organizing systems dedicated to dealing with rapidly changing environments affording flexibility of behavioural patterning. (shrink)

According to higher-order thought accounts of phenomenal consciousness it is unlikely that many non-human animals undergo phenomenally conscious experiences. Many people believe that this result would have deep and far-reaching consequences. More specifically, they believe that the absence of phenomenal consciousness from the rest of the animal kingdom must mark a radical and theoretically significant divide between ourselves and other animals, with important implications for comparative psychology. I shall argue that this belief is mistaken. Since phenomenal consciousness might be almost (...) epiphenomenal in its functioning within human cognition, its absence in animals may signify only relatively trivial differences in cognitive architecture. Our temptation to think otherwise arises partly as a side-effect of imaginative identification with animal experiences, and partly from mistaken beliefs concerning the aspects of common-sense psychology that carry the main explanatory burden, whether applied to humans or to non-human animals. (shrink)

We study the possible connection between self-consciousness and quantum process. It is shown that the self-consciousness function can help to measure the collapse time of wave function under some condition, while the usual physical device without self-consciousness can't. Furthermore, we show that the observer with self-consciousness can distinguish the definite state and the superposition of definite states under some stronger condition. This provides a practical physical method to differentiate man and machine, and will also help to find the possible existence (...) of self-consciousness in the animal kingdom. We finally give some further discussions about these new results. (shrink)

Our reply is in three parts. The first part concerns some foundational issues in the debate about color realism. The second part addresses the many objections to the version of physicalism about color ("productance physicalism") defended in the target article. The third part discusses the leading alternative approaches and theories endorsed by the commentators.

When do children become consciously aware of events in the world? Five possible strategies are considered for their usefulness in determining the age in question. Three of these strategies ask when children show signs of engaging in activities for which conscious awareness seems necessary in adults , and two of the strategies consider when children have the ability to have the minimal form of higher-order thought necessary for access consciousness and phenomenal consciousness, respectively. The tentative answer to the guiding question (...) is that children become consciously aware between 12 and 15 months. (shrink)

The conclusion of physics, within both a historical and more recent context, that an objectively progressive time and present moment are derivative notions without actual physical foundation in nature, illustrate that these perceived chronological features originate from subjective conscious experience and the neurobiological processes underlying it. Using this conclusion as a stepping stone, it is posited that the phenomena of an in-built subjective conception of a progressive present moment in time and that of conscious awareness are actually one and the (...) same thing, and as such, are also the outcome of the same neurobiological processes. A possible explanation as to how this might be achieved by the brain through employing the neuronal induced nonconscious cognitive manipulation of a small interval of time is proposed. The CIP phenomenon, elucidated within the context of this study is also then discussed. (shrink)

According to rich views of consciousness (e.g., James, Searle), we have a constant, complex flow of experience (or 'phenomenology') in multiple modalities simultaneously. According to thin views (e.g., Dennett, Mack and Rock), conscious experience is limited to one or a few topics, regions, objects, or modalities at a time. Existing introspective and empirical arguments on this issue (including arguments from 'inattentional blindness') generally beg the question. Participants in the present experiment wore beepers during everyday activity. When a beep sounded, they (...) were to take note of the conscious experience, if any, they were having at the last undisturbed moment immediately prior to the beep. Some participants were asked to report any experience they could remember. Others were asked simply to report whether there was visual experience or not (and if so, what it was). Still others were asked about experience in the far right visual field, or tactile experience, or tactile experience in the left foot. A majority of participants in the full experience and the visual conditions reported visual experience in every single sample. Tactile and peripheral visual experience were reported less often. However, the proper interpretation of these results is uncertain. (shrink)

The objectives of this article are twofold. First, by denying the dualism inherent in attempts to load metaphysical significance on the inner/outer distinction, it defends the view that scientific investigation can approach consciousness in itself, and is not somehow restricted in scope to the outward manifestations of a private and hidden realm. Second, it provisionally endorses the central tenets of global workspace theory, and recommends them as a possible basis for the sort of scientific understanding of consciousness thus legitimised. However, (...) the article goes on to argue that global workspace theory alone does not constitute a fully worked-out objective account of the conscious subject. This requires additional attention to be paid to the issue of embodiment, and to the possibility of indexicality that arises when an instantiation of the global workspace architecture inhabits a spatially localised body. (shrink)

In addressing thescientific study of consciousness, Crick and Koch state, It is probable that at any moment some active neuronal processes in your head correlate with consciousness, while others do not: what is the difference between them? (1998, p. 97). Evidence from electrophysiological and brain-imaging studies of binocular rivalry supports the premise of this statement and answers to some extent, the question posed. I discuss these recent developments and outline the rationale and experimental evidence for the interhemispheric switch hypothesis of (...) perceptual rivalry. According to this model, the perceptual alternations of rivalry reflect hemispheric alternations, suggesting that visual consciousness of rivalling stimuli may be unihemispheric at any one time (Miller et al., 2000). However, in this paper, I suggest that interhemispheric switching could involve alternating unihemispheric attentional selection of neuronal processes for access to visual consciousness. On this view, visual consciousness during rivalry could be bi hemispheric because the processes constitutive of attentional selection may be distinct from those constitutive of visual consciousness. This is a special case of the important distinction between the neuronal correlates and constitution of visual consciousness. (shrink)

The existence of neural correlates of consciousness (NCC) is not enough for philosophical purposes. On the other hand, there's more to NCC than meets the sceptic's eye. (I) NCC are useful for a better understanding of conscious experience, for instance: (1) NCC are helpful to explain phenomenological features of consciousness – e.g., dreaming. (2) NCC can account for phenomenological opaque facts – e.g., the temporal structure of consciousness. (3) NCC reveal properties and functions of consciousness which cannot be elucidated either (...) by introspective phenomenology or by psychological experiments alone – e.g., vision. (II) There are crucial problems and shortcomings of NCC: (1) Correlation implies neither causation nor identity. (2) There are limitations of empirical access due to the problem of other minds and the problem of self-deception, and (3) due to the restrictions provided by inter- and intraindividual variations. (4) NCC cannot be catched by neuroscience alone because of the externalistic content of representations. Therefore, NCC are not sufficient for a naturalistic theory of mind, (5) nor are they necessary because of the possibility of multiple realization. (III) Nevertheless, NCC are relevant and important for the mind-body problem: (1) NCC reveal features that are necessary at least for behavioral manifestations of human consciousness. (2) But NCC are compatible with very different proposals for a solution of the mind-body problem. This seems to be both advantageous and detrimental. (3) NCC restrict nomological identity accounts. (4) The investigation of NCC can refute empirical arguments for interactionism as a case study of John Eccles' dualistic proposals will show. (5) The discoveries of NCC cannot establish a naturalistic theory of mind alone, for which, e.g., a principle of supervenience and a further condition – and therefore philosophical arguments – are required. (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 paper appears in _Toward a Science of Consciousness II: The Second Tucson Discussions and Debates_ (S. Hameroff, A. Kaszniak, and A.Scott, eds), published with MIT Press in 1998. It is a transcript of my talk at the second Tucson conference in April 1996, lightly edited to include the contents of overheads and to exclude some diversions with a consciousness meter. A more in-depth argument for some of the claims in this paper can be found in Chapter 6 of my (...) book _The Conscious Mind_ (Chalmers, 1996). ]]. (shrink)

The search for neural correlates of consciousness (or NCCs) is arguably the cornerstone in the recent resurgence of the science of consciousness. The search poses many difficult empirical problems, but it seems to be tractable in principle, and some ingenious studies in recent years have led to considerable progress. A number of proposals have been put forward concerning the nature and location of neural correlates of consciousness. A few of these include.

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)

In the good old days, when general philosophy of science ruled the Earth, a simple division was often invoked to talk about philosophical issues specific to particular kinds of science: that between the natural sciences and the social sciences. Over the last 20 years, philosophical studies shaped around this dichotomy have given way to those organized by more fine-grained categories, corresponding to specific disciplines, as the literatures on the philosophy of physics, biology, economics and psychology--to take the most prominent four (...) examples--have blossomed. In general terms, work in each of these areas has become increasingly enmeshed with that in the corresponding science itself, increasingly naturalistic (in at least one sense of that term), and in my view, increasingly interesting. (shrink)

Electronic Mail: [email protected] Abstract Stability of activation, while it may be necessary for information to become available to consciousness, is not sufficient to produce phenomenal experience. We suggest that consciousness involves access to information and that access makes information symbolic. From this perspective, implicit representations exist, and are best thought of as sub-symbolic. Crucially, such representations can be causally efficacious in the absence of consciousness.

While the study of implicit learning is nothing new, the field as a whole has come to embody — over the last decade or so — ongoing questioning about three of the most fundamental debates in the cognitive sciences: The nature of consciousness, the nature of mental representation (in particular the difficult issue of abstraction), and the role of experience in shaping the cognitive system. Our main goal in this chapter is to offer a framework that attempts to integrate current (...) thinking about these three issues in a way that specifically links consciousness with adaptation and learning. Our assumptions about this relationship are rooted in further assumptions about the nature of processing and of representation in cognitive systems. When considered together, we believe that these assumptions offer a new perspective on the relationships between conscious and unconscious processing and on the function of consciousness in cognitive systems. (shrink)

Despite its significance in neuroscience and computation, McCulloch and Pitts's celebrated 1943 paper has received little historical and philosophical attention. In 1943 there already existed a lively community of biophysicists doing mathematical work on neural networks. What was novel in McCulloch and Pitts's paper was their use of logic and computation to understand neural, and thus mental, activity. McCulloch and Pitts's contributions included (i) a formalism whose refinement and generalization led to the notion of finite automata (an important formalism in (...) computability theory), (ii) a technique that inspired the notion of logic design (a fundamental part of modern computer design), (iii) the first use of computation to address the mind–body problem, and (iv) the first modern computational theory of mind and brain. (shrink)

The ability to predict is the most importantability of the brain. Somehow, the cortex isable to extract regularities from theenvironment and use those regularities as abasis for prediction. This is a most remarkableskill, considering that behaviourallysignificant environmental regularities are noteasy to discern: they operate not only betweenpairs of simple environmental conditions, astraditional associationism has assumed, butamong complex functions of conditions that areorders of complexity removed from raw sensoryinputs. We propose that the brain's basicmechanism for discovering such complexregularities is implemented in (...) the dendritictrees of individual pyramidal cells in thecerebral cortex. Pyramidal cells have 5–8principal dendrites, each of which is capableof learning nonlinear input-to-outputtransfer functions. We propose that eachdendrite is trained, in learning its transferfunction, by all the other principal dendritesof the same cell. These dendrites teach eachother to respond to their separate inputs with matching outputs. Exposed to differentbut related information about the sensoryenvironment, principal dendrites of the samecell tune to functions over environmentalconditions that, while different, are correlated . As a result, the cell as awhole tunes to the source of the regularitiesdiscovered by the cooperating dendrites,creating a new representation. When organizedinto feed-forward/feedback layers, pyramidalcells can build their discoveries on thediscoveries of other cells, graduallyuncovering nature's hidden order. Theresulting associative network is powerfulenough to meet a troubling traditionalobjection to associationism: that it is toosimple an architecture to implement rationalprocesses. (shrink)

According to some philosophers, computational explanation is proprietary
to psychology—it does not belong in neuroscience. But neuroscientists routinely offer computational explanations of cognitive phenomena. In fact, computational explanation was initially imported from computability theory into the science of mind by neuroscientists, who justified this move on neurophysiological grounds. Establishing the legitimacy and importance of computational explanation in neuroscience is one thing; shedding light on it is another. I raise some philosophical questions pertaining to computational explanation and outline some promising answers that (...) are being developed by a number of authors. (shrink)

When cognitive scientists apply computational theory to the problem of phenomenal consciousness, as many of them have been doing recently, there are two fundamentally distinct approaches available. Either consciousness is to be explained in terms of the nature of the representational vehicles the brain deploys; or it is to be explained in terms of the computational processes defined over these vehicles. We call versions of these two approaches _vehicle_ and _process_ theories of consciousness, respectively. However, while there may be space (...) for vehicle theories of consciousness in cognitive science, they are relatively rare. This is because of the influence exerted, on the one hand, by a large body of research which purports to show that the explicit representation of information in the brain and conscious experience are _dissociable_, and on the other, by the _classical_ computational theory of mind – the theory that takes human cognition to be a species of symbol manipulation. But two recent developments in cognitive science combine to suggest that a reappraisal of this situation is in order. First, a number of theorists have recently been highly critical of the experimental methodologies employed in the dissociation studies – so critical, in fact, it’s no longer reasonable to assume that the dissociability of conscious experience and explicit representation has been adequately demonstrated. Second, classicism, as a theory of human cognition, is no longer as dominant in cognitive science as it once was. It now has a lively competitor in the form of _connectionism; _and connectionism, unlike classicism, does have the computational resources to support a robust vehicle theory of consciousness. In this paper we develop and defend this connectionist vehicle theory of consciousness. It takes the form of the following simple empirical hypothesis: _phenomenal experience consists in the explicit_ _representation of information in neurally realized PDP networks_.. (shrink)

Mind–body dualism has rarely been an issue in the generative study of mind; Chomsky himself has long claimed it to be incoherent and unformulable. We first present and defend this negative argument but then suggest that the generative enterprise may license a rather novel and internalist view of the mind and its place in nature, different from all of, (i) the commonly assumed functionalist metaphysics of generative linguistics, (ii) physicalism, and (iii) Chomsky’s negative stance. Our argument departs from the empirical (...) observation that the linguistic mind gives rise to hierarchies of semantic complexity that we argue (only) follow from constraints of an essentially mathematical kind. We assume that the faculty of language tightly correlates with the mathematical capacity both formally and in evolution, the latter plausibly arising as an abstraction from the former, as a kind of specialized output. On this basis, and since the semantic hierarchies in question are mirrored in the syntactic complexity of the expression involved, we posit the existence of a higher-dimensional syntax structured on the model of the hierarchy of numbers, in order to explain the semantic facts in question. If so, syntax does not have a physicalist interpretation any more than the hierarchy of number-theoretic spaces does. (shrink)

We describe an emerging field, that of nonclassical computability and nonclassical computing machinery. According to the nonclassicist, the set of well-defined computations is not exhausted by the computations that can be carried out by a Turing machine. We provide an overview of the field and a philosophical defence of its foundations.

A myth has arisen concerning Turing's paper of 1936, namely that Turing set forth a fundamental principle concerning the limits of what can be computed by machine - a myth that has passed into cognitive science and the philosophy of mind, to wide and pernicious effect. This supposed principle, sometimes incorrectly termed the 'Church-Turing thesis', is the claim that the class of functions that can be computed by machines is identical to the class of functions that can be computed by (...) Turing machines. In point of fact Turing himself nowhere endorses, nor even states, this claim (nor does Church). I describe a number of notional machines, both analogue and digital, that can compute more than a universal Turing machine. These machines are exemplars of the class of _nonclassical_ computing machines. Nothing known at present rules out the possibility that machines in this class will one day be built, nor that the brain itself is such a machine. These theoretical considerations undercut a number of foundational arguments that are commonly rehearsed in cognitive science, and gesture towards a new class of cognitive models. (shrink)

The initial argument presented herein is not significantly original—it is a simple reflection upon a notion of computation originally developed by Putnam and criticised by Chalmers et al. . In what follows, instead of seeking to justify Putnam’s conclusion that every open system implements every Finite State Automaton and hence that psychological states of the brain cannot be functional states of a computer, I will establish the weaker result that, over a finite time window every open system implements the trace (...) of FSA Q, as it executes program on input . If correct the resulting bold philosophical claim is that phenomenal states—such as feelings and visual experiences—can never be understood or explained functionally. (shrink)

Some philosophers have conflated functionalism and computationalism. I reconstruct how this came about and uncover two assumptions that made the conflation possible. They are the assumptions that (i) psychological functional analyses are computational descriptions and (ii) everything may be described as performing computations. I argue that, if we want to improve our understanding of both the metaphysics of mental states and the functional relations between them, we should reject these assumptions. # 2004 Elsevier Ltd. All rights reserved.

According to the dominant computational approach in cognitive science, cognitive agents are digital computers; according to the alternative approach, they are dynamical systems. This target article attempts to articulate and support the dynamical hypothesis. The dynamical hypothesis has two major components: the nature hypothesis (cognitive agents are dynamical systems) and the knowledge hypothesis (cognitive agents can be understood dynamically). A wide range of objections to this hypothesis can be rebutted. The conclusion is that cognitive systems may well be dynamical systems, (...) and only sustained empirical research in cognitive science will determine the extent to which that is true. (shrink)

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)