Visual Agnosia is a comprehensive and up-to-date review of disorders of higher vision that relates these disorders to current conceptions of higher vision from cognitive science, illuminating both the neuropsychological disorders and the nature of normal visual object recognition.Brain damage can lead to selective problems with visual perception, including visual agnosia the inability to recognize objects even though elementary visual functions remain unimpaired. Such disorders are relatively rare, yet they provide a window onto how the normal brain might accomplish the (...) complex task of vision. Visual Agnosia reviews a century of case studies of higher-level visual deficits following brain damage, places them in the general context of current neuroscience, and draws relevant conclusions about the organization of normal visual processing. It is unique in drawing on research in cognitive psychology, computational vision, visual neurophysiology, and neuropsychology to interpret the agnosias and draw inferences from them about visual object recognition.Following a historical account of agnosia research, Visual Agnosia offers a taxonomy of a wide range of agnosia syndromes, describing and interpreting the syndromes in terms of the latest theoretical models of visual processing and ultimately bringing them to bear as evidence on a variety of questions in the study of higher vision.Martha J. Farah is Associate Professor of Psychology at Carnegie Mellon University. Visual Agnosia is included in the Issues in Biology of Language and Cognition series, edited by John Marshall. (shrink)

I explicate the Churchland's dualistic interaction and neural dependence objections to Cartesian dualism and argue that Aquinas’s conception of Aristotelian hylomorphism provides a way out of those objections. -/- .

At any given time, a subject has a multiplicity of conscious experiences. A subject might simultaneously have visual experiences of a red book and a green tree, auditory experiences of birds singing, bodily sensations of a faint hunger and a sharp pain in the shoulder, the emotional experience of a certain melancholy, while having a stream of conscious thoughts about the nature of reality. These experiences are distinct from each other: a subject could experience the red book without the singing (...) birds, and could experience the singing birds without the red book. But at the same time, the experiences seem to be tied together in a deep way. They seem to be unified, by being aspects of a single encompassing state of consciousness. (shrink)

To make progress on the problem of consciousness, we have to confront it directly. In this paper, I first isolate the truly hard part of the problem, separating it from more tractable parts and giving an account of why it is so difficult to explain. I critique some recent work that uses reductive methods to address consciousness, and argue that such methods inevitably fail to come to grips with the hardest part of the problem. Once this failure is recognized, the (...) door to further progress is opened. In the second half of the paper, I argue that if we move to a new kind of nonreductive explanation, a naturalistic account of consciousness can be given. I put forward my own candidate for such an account: a nonreductive theory based on principles of structural coherence and organizational invariance, and a double-aspect theory of information. (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)

In this important book, Susan Hurley sheds new light on consciousness by examining its relationships to action from various angles. She assesses the role of agency in the unity of a conscious perspective, and argues that perception and action are more deeply interdependent than we usually assume. A standard view conceives perception as input from world to mind and action as output from mind to world, with the serious business of thought in between. Hurley criticizes this picture, and considers how (...) the interdependence of perceptual experience and agency at the personal level (of mental contents and norms) may emerge from the subpersonal level (of underlying causal processes and complex dynamic feedback systems). Her two-level view has wide implications, for topics that include self-consciousness, the modularity of mind, and the relations of mind to world. The self no longer lurks hidden somewhere between perceptual input and behavioral output, but reappears out in the open, embodied and embedded in its environment. Hurley traces these themes from Kantian and Wittgensteinian arguments through to intriguing recent work in neuropsychology and in dynamic systems approaches to the mind, providing a bridge from mainstream philosophy to work in other disciplines. Consciousness in Action is unique in the range of philosophical and scientific work it draws on, and in the deep criticism it offers of centuries-old habits of thought. (shrink)

_Stream of Consciousness_ is about the phenomenology of conscious experience. Barry Dainton shows us that stream of consciousness is not a mosaic of discrete fragments of experience, but rather an interconnected flowing whole. Through a deep probing into the nature of awareness, introspection, phenomenal space and time consciousness, Dainton offers a truly original understanding of the nature of consciousness.

[opening paragraph] -- Clark: The `astonishing hypothesis' which you put forward in your book, and which you obviously feel is very controversial, is that `You, your joys and sorrows, your memories and ambitions, your sense of personal identity and free will are, in fact, no more than the behaviour of a vast assembly of nerve cells. As Lewis Carroll's Alice might have phrased it: `You're nothing but a pack of neurons'.' But it seems to me that this is not so (...) astonishing a statement for a scientist to make. Isn't this what reductionist science has always believed? (shrink)

This paper develops an empirically motivated theory of visual consciousness. It begins by outlining neuropsychological support for Jackendoff's (1987) hypothesis that visual consciousness involves mental representations at an intermediate level of processing. It then supplements that hypothesis with the further requirement that attention, which can come under the direction of high level representations, is also necessary for consciousness. The resulting theory is shown to have a number of philosophical consequences. If correct, higher-order thought accounts, the multiple drafts account, and the (...) widely held belief that sensation precedes perception will all be found wanting. The theory will also be used to illustrate and defend a methodology that fills the gulf between functionalists who ignore the brain and neural reductionists who repudiate functionalism. (shrink)

Human agents draw a variety of inferences effortlessly, spontaneously, and with remarkable efficiency – as though these inferences were a reflexive response of their cognitive apparatus. Furthermore, these inferences are drawn with reference to a large body of background knowledge. This remarkable human ability seems paradoxical given the complexity of reasoning reported by researchers in artificial intelligence. It also poses a challenge for cognitive science and computational neuroscience: How can a system of simple and slow neuronlike elements represent a large (...) body of systemic knowledge and perform a range of inferences with such speed? We describe a computational model that takes a step toward addressing the cognitive science challenge and resolving the artificial intelligence paradox. We show how a connectionist network can encode millions of facts and rules involving n-ary predicates and variables and perform a class of inferences in a few hundred milliseconds. Efficient reasoning requires the rapid representation and propagation of dynamic bindings. Our model (which we refer to as SHRUTI) achieves this by representing (1) dynamic bindings as the synchronous firing of appropriate nodes, (2) rules as interconnection patterns that direct the propagation of rhythmic activity, and (3) long-term facts as temporal pattern-matching subnetworks. The model is consistent with recent neurophysiological evidence that synchronous activity occurs in the brain and may play a representational role in neural information processing. The model also makes specific psychologically significant predictions about the nature of reflexive reasoning. It identifies constraints on the form of rules that may participate in such reasoning and relates the capacity of the working memory underlying reflexive reasoning to biological parameters such as the lowest frequency at which nodes can sustain synchronous oscillations and the coarseness of synchronization. (shrink)

We provide a critique of the usual functionalist, cognition-first reading of Aristotle’s theory of emotion and then offer an alternative understanding of Aristotle's theory of cognition and emotion that brings to bear certain biological considerations evidenced in his arguments on the integration of form and matter (hylomorphism) and the hierarchical organization of the biological world. This, of course, does not suggest that we are critical of all varieties of functionalism, but only those which fail to utilize and incorporate findings in (...) neuroscience. One way to help bridge the gap between mind and the physical world is through empirical findings. Based upon our new reading of Aristotle, we identify affinities with contemporary research in the cognitive neuroscience of emotion and developmental research on emotion. (shrink)

It is important to separate the question of binding from the problem of consciousness. Undoubtedly, there are some close connections between the two: my conscious experience is of a bound unity. But my unconscious experiences -- subliminal impressions, masked primings, etc. -- might be bound too for all I know. Hence, some of the recent commentators speak too loosely when they talk of 40 Hz oscillations solving some problem of conscious perception.

In attempts to formulate a computational understanding of brain function, one of the fundamental concerns is the data structure by which the brain represents information. For many decades, a conceptual framework has dominated the thinking of both brain modelers and neurobiologists. That framework is referred to here as "classical neural networks." It is well supported by experimental data, although it may be incomplete. A characterization of this framework will be offered in the next section. Difficulties in modeling important functional aspects (...) of the brain on the basis of classical neural networks alone have led to the recognition that another, general mechanism must be invoked to explain brain function. That mechanism I call " binding." Binding by neural signal synchrony had been mentioned several times in the liter ature before it was fully formulated as a general phenomenon. Although experimental evidence for neural syn chrony was soon found, the idea was largely ignored for many years. Only recently has it become a topic of animated discussion. In what follows, I will summarize the nature and the roots of the idea of binding, especially of temporal binding, and will discuss some of the objec tions raised against it. (shrink)

Hurley’s is a difficult book to work through—partly because of its length and the complexity of its arguments, but also because each of the ten essays of which it is composed has a rather different starting point and focus, and because few of her arguments achieve real closure. Essay 2 discusses competing interpretations of Kant, essay 4 articulates nonconceptual forms of self-consciousness, essay 5 offers fresh interpretations of commissurotomy patients’ behavior, essay 6 develops an objection to Wittgenstein on rule following, (...) essay 8 attacks an alleged assumption of externalism, and chapter 10 explores the possibility of combining a “motor theory” and a “control theory” of perception. This is a very rich brew, and at least half the challenge this book presents consists in discerning its central argument and conclusion with enough precision to bring criticism to bear. (shrink)

The discussion begins with a familiar and defensible characterization of the eureka moment, according to which it is the unexpected product of separate and often seemingly incompatible perspectives. The principal aim of the discussion is to explain how, so characterized, vision-related eureka moments can occur. To fulfill this aim, the discussion employs a notion of crosstalk, in which cognitive interference slightly increases as a result of the creative thinker's considerable, albeit only partly successful, pre-eureka cognitive effort. Such crosstalk, it is (...) suggested, is likely to occur when top-down visual imaging repeatedly stimulates pyramidal cells closely apposed to others that, although simultaneously active, are part of bottom-up visual perception that is initially cognitively unrelated to such imaging. It is further suggested that local circuitry, in the form of inhibitory interneurons, can synchronize cells associated with these initially separate processes, thus causing subsequent perceptual patterns to be subtly modified by pre-eureka problem-solving imagery. This modification, it is claimed, may help explain the unexpected shift in visual perception that accompanies the creative thinker's eureka moment, a shift that can improve the thinker's subsequent understanding of the relevance of information to a problem's solution. (shrink)