Abstract: Patients may show a more-or-less complete deviation of the head and eyes towards the right (ipsilesional) side [that is, to the same side of egocentric space as the brain lesion responsible for their disorder]. If addressed by the examiner from the left (contralesional) side [the opposite side to their lesion], patients with severe extrapersonal neglect may fail to respond or may look for the speaker in the right side of the room, turning head and eyes more and more to the right. Frequently these patients will not pick up food from the left half of the plate. Given a crossword puzzle, they may complete only the squares to the right. If walking is not prevented by hemiparesis, neglect patients may lose their bearings, since they do not make use of left sided cues

Abstract: Forthcoming in Lana Trick & Don Dedrick (eds.), Cognition, Computation, and Pylyshyn. MIT Press. Presented at the Zenon Pylyshyn Conference (ZenCon), University of Guelph, 1 May 2005

Abstract: [1] It is well-known that Evans laid the groundwork for a truly radical and fruitful theory of _content_ -- a theory according to which content is a genus with at least conceptual and nonconceptual varieties as species, and in which nonconceptual content plays a very significant role. It is less well-recognized that Evans was also in the process of working out the details of a truly radical and groundbreaking theory of _representation_, a task he was unfortunately unable to bring to any satisfactory stage of fruition. I am here drawing the distinction between a theory of

Abstract: b>: The problem of how physical systems, such as brains, come to represent themselves as subjects in an objective world is addressed. I develop an account of the requirements for this ability that draws on and refines work in a philosophical tradition that runs from Kant through Peter Strawson to Gareth Evans. The basic idea is that the ability to represent oneself as a subject in a world whose existence is independent of oneself involves the ability to represent space, and in particular, to represent oneself as one object among others in an objective spatial realm. In parallel, I provide an account of how this ability, and the mechanisms that support it, are realized neurobiologically. This aspect of the article draws on, and refines, work done in the neurobiology and psychology of egocentric and allocentric spatial representation

Abstract: Visual space can be distinguished from physical space. The first is found in visual experi- ence, while the second is defined independently of perception. Theorists have wondered about the relation between the two. Some investigators have concluded that visual space is non- Euclidean, and that it does not have a single metric structure. Here it is argued (1) that visual space exhibits contraction in all three dimensions with increasing distance from the observer, (2) that experienced features of this contraction (including the apparent convergence of lines in visual experience that are produced from physically parallel stimuli in ordinary viewing con- ditions) are not the same as would be the experience of a perspective projection onto a fronto- parallel plane, and (3) that such contraction is consistent with size constancy. These properties of visual space are different from those that would be predicted if spatial perception resulted from the successful solution of the inverse problem. They are consistent with the notion that optical constraints have been internalized. More generally, they are also consistent with the notion that visual spatial structures bear a resemblance relation to physical spatial structures. This notion supports a type of representational relation that is distinct from mere causal cor- respondence. The reticence of some philosophers and psychologists to discuss the structure of phenomenal space is diagnosed in terms of the simple materialism and the functionalism of the 1970s and 1980s. Ó 2003 Elsevier B.V. All rights reserved

Abstract: I propose and defend the Allocentric-Egocentric Interface Theory of Con- sciousness. Mental processes form a hierarchy of mental representations with maxi- mally egocentric (self-centered) representations at the bottom and maximally allocentric (other-centered) representations at the top. Phenomenally conscious states are states that are relatively intermediate in this hierarchy. More speci¯cally, conscious states are hybrid states that involve the reciprocal interaction between relatively allocentric and relatively egocentric representations. Thus a conscious state is composed of a pair of representations interacting at the Allocentric-Egocentric Interface. What a person is conscious of is determined by what the contributing allocentric and egocentric represen- tations are representations of. The phenomenal character of conscious states is identical to the representational content of the reciprocally interacting egocentric and allocentric representations

Abstract: According to representionalists, qualia-the introspectible properties of sensory experience-are exhausted by the representational contents of experience. Representationalists typically advocate an informational psychosemantics whereby a brain state represents one of its causal antecedents in evolutionarily determined optimal circumstances. I argue that such a psychosemantics may not apply to certain aspects of our experience, namely, our experience of space in vision, hearing, and touch. I offer that these cases can be handled by supplementing informational psychosemantics with a procedural psychosemantics whereby a representation is about its effects instead of its causes. I discuss conceptual and empirical points that favor a procedural representationalism for our experience of space

Abstract: This paper, which has both a historical and a polemical aspect, investigates the view, dominant throughout the eighteenth and nineteenth centuries, that the sense of sight is, originally, not phenomenally three-dimensional in character, and that we must come to interpret its properly two-dimensional data by reference to the sense of 'touch'. The principal argument for this claim, due to Berkeley, is examined and found wanting. The supposedly confirming findings concerning 'Molyneux subjects' are also investigated and are shown to be either irrelevant or disconfirming. Recent investigations on infant and neonatal perception are discussed and are also found to be disconfirming. An innatist version of the theory is then considered and is shown to be undermined by the largely 'Gibsonian' character of early space-perception. Finally three recent arguments in favour of the theory - two from psychologists, one from a philosopher - are considered and answered

Abstract: To what extent is the external world the way that it appears to us in perceptual experience? This perennial question in philosophy is no doubt ambiguous in many ways. For example, it might be taken as equivalent to the question of whether or not the external world is the way that it appears to be? This is a question about the epistemology of perception: Are our perceptual experiences by and large veridical representations of the external world?

Abstract: The notion of conceptuality is still unclear and vague. I will present a definition of conceptual and nonconceptual representations that is grounded in different aspects of the representations' structures. This definition is then used to interpret empirical results from human and animal navigation. It will be shown, that the distinction between egocentric and allocentric spatial representations can be matched onto the conceptual vs. nonconceptual distinction. The phenomena discussed in spatial navigation are thereby put into a wider context of cognitive abilities, which allows for new explanations of certain features of spatial representations and how they are linked to other capacities, like perception and reasoning