The Conscious Brain brings neuroscientific evidence to bear on enduring philosophical questions. Major philosophical and scientific theories of consciousness are surveyed, challenged, and extended.

The dissociation Block provides between phenomenal and access consciousness (P-consciousness and A-consciousness) captures much of our intuition about conscious experience. However, it raises a major methodological puzzle, and is not uniquely supported by the empirical evidence. We provide an alternative interpretation based on the notion of levels of representation and partial awareness.

Philosophers debate whether all, some or none of the represcntational content of our sensory experience is conccptual, but the technical term "concept" has different uses. It is commonly linked more or less closely with the notions of judgdment and reasoning, but that leaves open the possibility that these terms share a systematic ambiguity or indeterminacy. Donald Davidson, however, holds an unequivocal and consistent, if paradoxical view that there are strictly speaking no psychological states with representational or intentional content except the (...) propositional attitudes of language users, since thc source or fundamental bearer of intentionality is the employed sentence. Accordingly he claims that what has content in ordinary sense experience is not sensation, but propositional belief caused, but not justified, by sensation. John McDowell, sharing some ofDavidson's premises,holds a less paradoxical, but (l will argue) equivocal and incoherent view that post-infantile human sensory expcrience must have content in so far as it is what grounds perceptual belief but that this content is itself conceptual or propositional, dependent on language and culture. Reasons are givcn in the present article for rejecting both views, and their common premises. It is argued that perceptual or sensory states have intentional content which is no more conceptual or propositional than the world is. Recognition that perceptual content and conceptual content are, in a certain unsurprising way incommensurable allows for a more realistic understanding of the relationship between Language and the world as we experience it. (shrink)

How do rational minds make contact with the world? The empiricist tradition sees a gap between mind and world, and takes sensory experience, fallible as it is, to provide our only bridge across that gap. In its crudest form, for example, the traditional idea is that our minds consult an inner realm of sensory experience, which provides us with evidence about the nature of external reality. Notoriously, however, it turns out to be far from clear that there is any viable (...) conception of experience which allows it to do the job. The original problem is to show that thought is rationally constrained by external reality. If sensory experience is to provide the solution--in particular, if it is to provide the answer to sceptical challenges--it must therefore meet two criteria. First, it must itself be `receptive'--i.e., appropriately constrained by external reality. Second, it must be the kind of thing that can enter into a logical or rational relationship with belief--it must already be `conceptual,' in other words. In arguing against the idea that anything could serve both roles, Wilfred Sellars termed this conception of experience "the Myth of the Given.". (shrink)

An argument that there are perceptual mechanisms that retrieve information in cognitively and conceptually unmediated ways and that this sheds light on various ...

This essay is a long one. It is not meant to be read in a single sitting. Its structure is as follows. In section I, I explicate perceptual anti-individualism. Section II centers on the two aspects of the representational content of perceptual states. Sections III and IV concern the nature of the empirical psychology of vision, and its bearing on the individuation of perceptual states. Section V shows how what is known from empirical psychology undermines disjunctivism and hence certain further (...) views that entail it, including naive realism. In Section VI, I raise a further point against disjunctivism. Section VII indicates how general reflection on perceptual perspective and epistemic ability supports the constraints from empirical psychology. It also explains how reflection on veridicality conditions, psychological explanation, and cognitive ability conspire to force recognition of the two kinds of representation mentioned in the preceding paragraph. In the Appendix, I criticize attempts to support disjunctivism. (shrink)

In this new book, John McDowell builds on his much discussed Mind and World—one of the most highly regarded books in contemporary philosophy.

This article concerns the interplay between two issues that involve both philosophy and neuroscience: whether the content of phenomenal consciousness is 'rich' or 'sparse', whether phenomenal consciousness goes beyond cognitive access, and how it would be possible for there to be evidence one way or the other.

In Mind and World, John McDowell argues against the view that perceptual representation is non-conceptual. The central worry is that this view cannot offer any reasonable account of how perception bears rationally upon belief. I argue that this worry, though sensible, can be met, if we are clear that perceptual representation is, though non-conceptual, still in some sense 'assertoric': Perception, like belief, represents things as being thus and so.

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)

Much as we would like to conceive empirical thought as rationally grounded in experience, pitfalls await anyone who tries to articulate this position, and ...

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)

Bill Brewer presents an original view of the role of conscious experience in the acquisition of empirical knowledge. He argues that perceptual experiences must provide reasons for empirical beliefs if there are to be any determinate beliefs at all about particular objects in the world. This fresh approach to epistemology turns away from the search for necessary and sufficient conditions for knowledge and works instead from a theory of understanding in a particular area.

A number of authors have argued recently that the content of perceptual experience can, and even must, be characterized in conceptual terms. Their claim, more precisely, is that every perceptual experience is such that, of necessity, its content is constituted entirely by concepts possessed by the subject having the experience. This is a surprising result. For it seems reasonable to think that a subject’s experiences could be richer and more fine-grained than his conceptual repertoire; that a subject might be able, (...) for example, to discriminate in experience more shades of colors than he has color concepts. The key move in their argument, therefore, is to articulate the conceptual content of experience using demonstrative, instead of general, concepts. For instance, these authors argue that the content of my perceptual experience of a particular shade of green is properly characterized in terms of the concept expressed by the linguistic utterance “that shade”. Even if I don’t possess a general concept for the shade I’m seeing—a concept of the kind typically expressed using color names like ‘chartreuse’ or ‘lime’—nevertheless, these authors argue, the content of the experience can still be characterized conceptually using a demonstrative concept that I do possess. (shrink)

The idea of nonconceptual contents proposes that there are mental contents at the level of the experiencing person that are individuated independently of ‘anything to do with the mind.’ Such contents are posited to meet a variety of theoretical and explanatory needs concerning concepts and conceptual mental contents which are individuated in terms having to do with the mind. So to examine the idea of nonconceptual content we need to examine whether we really need to posit such content and whether (...) there is a coherent, viable way of doing so. I will examine the idea of nonconceptual contents by considering Christopher Peacocke's attempt, in his Study of Concepts, to posit such contents.Three principal kinds of considerations motivate positing non-conceptual content: epistemological, phenomenological, and explanatory-psychological. A theory of knowledge might posit nonconceptual content in order to show that our experience contains the justificatory base for empirical thought as its own proper part. Non-conceptual content might also be posited in order to account for the finely detailed or determinate phenomenological character of perceptual experience. (shrink)

I take it for granted that sense experiential states provide reasons for empirical beliefs; indeed this claim forms the first premise of my central argument for (CC). 1 The subsequent stages of the argument are intended to establish that a person has such a reason for believing something about the way things are in the world around him only if he is in some mental state or other with a conceptual content: a conceptual state. Thus, given that sense experiential states (...) do provide reasons for empirical beliefs, they must have conceptual content. (shrink)

Philosophers have often argued that ascriptions of content are appropriate only to the personal level states of folk psychology. Against this, this paper defends the view that the familiar propositional attitudes and states defined over them are part of a larger set of cognitive proceses that do not make constitutive reference to concept possession. It does this by showing that states with nonconceptual content exist both in perceptual experience and in subpersonal information-processing systems. What makes these states content-involving is their (...) satisfaction of certain basic conditions deriving from a general account of representation-driven behaviour that is neutral on the question of concept possession. It is also argued that creatures can be in states with nonconceptual content even though they possess no conceptual abilities at all. (shrink)

The paper develops a conception of epistemic warrant as applied to perceptual belief, called "entitlement", that does not require the warranted individual to be capable of understanding the warrant. The conception is situated within an account of animal perception and unsophisticated perceptual belief. It characterizes entitlement as fulfillment of an epistemic norm that is apriori associated with a certain representational function that can be known apriori to be a function of perception. The paper connects anti-individualism, a thesis about the nature (...) of mental states, and perceptual entitlement. It presents an argument that explains the objectivity and validity of perceptual entitlement partly in terms of the nature of perceptual states–hence the nature of perceptual beliefs, which are constitutively associated with perceptual states. The paper discusses ways that an individual can be entitled to perceptual belief through its connection to perception, and ways that entitlement to perceptual belief can be undermined. (shrink)

Experiments on scene perception and change blindness suggest that the visual system does not construct detailed internal models of a scene. These experiments therefore call into doubt the traditional view that vision is a process in which detailed representations of the environment must be constructed. The non-existence of such detailed representations, however, does not entail that we do not perceive the detailed environment. The “grand illusion hypothesis” that our visual world is an illusion rests on (1) a problematic “reconstructionist” conception (...) of vision, and (2) a misconception about the character of perceptual experience. (shrink)

In the past twenty years, issues about the relationship between perception and thought have largely been framed in terms of the question of whether the contents of perception are nonconceptual. I argue that this debate has rested on an ambiguity in `nonconceptual content' and some false presuppositions about what is required for concept possession. Once these are cleared away, I argue that none of the arguments which have been advanced about nonconceptual content do much to threaten the natural view that (...) perception and thought are relations to the same kind of content. (shrink)

Conceptualist accounts of the representational content of perceptual experiences have it that a subject _S_ can experience no object, property, relation, etc., unless _S_ "i# possesses and "ii# exercises concepts for such object, property, or relation. Perceptual experiences, on such a view, represent the world in a way that is conceptual.

Philosophers from Hume, Kant, and Wittgenstein to the recent realists and antirealists have sought to answer the question, What are concepts? This book provides a detailed, systematic, and accessible introduction to an original philosophical theory of concepts that Christopher Peacocke has developed in recent years to explain facts about the nature of thought, including its systematic character, its relations to truth and reference, and its normative dimension. Particular concepts are also treated within the general framework: perceptual concepts, logical concepts, and (...) the concept of belief are discussed in detail. The general theory is further applied in answering the question of how the ontology of concepts can be of use in classifying mental states, and in discussing the proper relation between philosophical and psychological theories of concepts. Finally, the theory of concepts is used to motivate a nonverificationist theory of the limits of intelligible thought. Peacocke treats content as broad rather than narrow, and his account is nonreductive and non-Quinean. Yet Peacocke also argues for an interactive relationship between philosophical and psychological theories of concepts, and he plots many connections with work in cognitive psychology. (shrink)

Can we ever experimentally disentangle phenomenal consciousness from the cognitive accessibility inherent to conscious reports? In this commentary, we suggest that (1) Block's notion of phenomenal consciousness remains intractably entangled with the need to obtain subjective reports about it; and (2) many experimental paradigms suggest that the intuitive notion of a rich but non-reportable phenomenal world is, to a large extent illusory – in a sense that requires clarification.

In this paper, we criticise the claim, made by J. McDowell and B. Brewer, that the contents of perceptual experience are purely conceptual.

It is now 25 years since Gareth Evans introduced the distinction between conceptual and nonconceptual content in The Varieties of Reference. This is a fitting time to take stock of what has become a complex and extended debate both within philosophy and at the interface between philosophy and psychology. Unfortunately, the debate has become increasingly murky as it has become increasingly ramified. Much of the contemporary discussion does not do full justice to the powerful theoretical tool originally proposed by Evans (...) and subsequently refined by theorists in the late 1980’s and early 1990’s – most effectively, I think, by Christopher Peacocke (particularly in his 1992). Even worse, significant parts of the discussion are somewhat confused. This paper makes a start on clarifying what I think ought to be the central issues in debates about nonconceptual content. I begin in §1 by pointing out how narrowly focused contemporary discussion is relative to Evans’s original discussion. We are not making as much use as we should of nonconceptual content as a tool for understanding subpersonal information processing and the complexities of its status relative to perception and thought at the personal level. In §2 I turn to what is the central focus of contemporary discussion, namely, the content of perception and identify a “master argument” for nonconceptualism based on the relation between conceptual capacities and capacities for perceptual discrimination. The aim of §3 is to clarify the relation between the claim that perception has nonconceptual content and some superficially similar claims discussed by philosophers of perception. Finally, in §4 I explain why the attention recently focused on what is sometimes called the state version of the nonconceptualist thesis seems to me to be misdirected. (shrink)

A further development of Tye's theory of phenomenal consciousness along with replies to common objections.

Consciousness, Color, and Content is a significant contribution to our understanding of consciousness, among other things. I have learned a lot from it, as well as Tye’s other writings. What’s more, I actually agree with much of it – fortunately for this symposium, not all of it. The book continues the defense of the “PANIC” theory of phenomenal consciousness that Tye began in Ten Problems of Consciousness (1995). A fair chunk of it, though, is largely independent of this theory: the (...) discussion of the knowledge argument, the explanatory gap, and color. Tye says much of interest about these topics. But as most of my disagreement is with the PANIC theory, I shall concentrate on that. The PANIC theory is nothing short of ambitious. It is a reductive account of phenomenal consciousness in intentional/functional terms. Tye further gives, at least in outline, a broadly physicalistic account of intentionality (a “naturalized semantics”), in terms of causal covariation. Putting the PANIC theory and Tye’s naturalized semantics together, the result is a physicalistically acceptable theory of phenomenal consciousness. The two parts of this package are independent. A naturalized semantics can be combined with dualism about consciousness (a position close to this is in Chalmers, 1996). And a PANIC theorist is at liberty to endorse a rival physicalistic theory of intentionality, or indeed could take intentionality to be entirely irreducible. The plan is this. Section 1 briefly airs a concern about Tye’s naturalized semantics. The rest of the paper focuses on the PANIC theory, in particular the use it makes of “nonconceptual content”.1 Philosophical Studies 113: 261–274, 2003. © 2003 Kluwer Academic Publishers. Printed in the Netherlands. 262.. (shrink)

Does attention alter appearance? This critical issue, debated for over a century, remains unsettled. From psychophysical evidence that covert attention affects early vision-it enhances contrast sensitivity and spatial resolution-and from neurophysiological evidence that attention increases the neuronal contrast sensitivity (contrast gain), one could infer that attention changes stimulus appearance. Surprisingly, few studies have directly investigated this issue. Here we developed a psychophysical method to directly assess the phenomenological correlates of attention in humans. We show that attention alters appearance; it boosts (...) the apparent stimulus contrast. These behavioral results are consistent with neurophysiological findings suggesting that attention changes the strength of a stimulus by increasing its 'effective contrast' or salience. (shrink)

In 1995, in my book, Ten Problems of Consciousness, I proposed a version of the theory of phenomenal consciousness now known as representationalism. The present book, in part, consists of a further development of that theory along with replies to common objections. It is also concerned with two prominent challenges for any reductive theory of consciousness: the explanatory gap and the knowledge argument. In addition, it connects representationalism with two more general issues: the nature of color and the location of (...) the phylogenetic dividing line between those creatures that are phenomenally conscious and those that are not. (shrink)

Block makes a case for the existence of conscious experience without access. His case would have been much stronger, however, if he had woven fully unconscious processing into the and considered arguments that are intrinsic to neuroscience.