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? Alternatively, the question might (...) be taken as asking whether or not the external world is like its ways of appearing to us, where the expression “ways of appearing” is intended to pick out aspects of our perceptual experiences themselves. This is a metaphysical version of the question of the relationship between appearance and reality: What is the relationship between the phenomenal features that characterize perceptual experience, on the one hand, and the mind-independent features of the external objects of perception, on the other? There are some philosophers who might resist distinguishing between these two questions. For them, “ways of appearing” in the phenomenal sense just are the ways that things appear to be (let’s call the latter the “intentional sense” of “ways of appearing”).1 That is, the phenomenal character of an experience is nothing over and above its representational content. Phenomenal properties are represented properties—the properties that an experience attributes to the external objects of perception. The question of whether or not phenomenal properties can be identified with the represented properties of an experience mirrors traditional questions in the philosophy of perception. If they can be identified with each other, then in veridical perception we might be said to “directly grasp” features of the external world through perception. The properties that are present to the mind are the very same properties that belong to the external objects of perception. Such a view affords.... (shrink)

Are objects in convex passenger-side mirrors “closer than they appear”? If one adapts to inverting goggles, does the world go back to looking the way it was before, or does the world look approximately the same throughout the course of adaptation, only losing its normative sense of wrongness? The answers to these empirical, introspective questions might help cast light on the classic philosophical debate about the degree of resemblance between our visual experience of reality and things as they are in (...) themselves. (shrink)

ABSTRACTThe standard view in philosophy of mind is that the way to understand the difference between perception and misperception is in terms of accuracy. On this view, perception is accurate while...

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)

Before one can talk about global arrays and multimodal detection, one must be clear about the concept of information: How is it different from energy and how is it detected? And can it come to specify a needed movement? We consider these issues in our commentary.

This paper is concerned with the problem of selfidentification in the domain of action. We claim that this problem can arise not just for the self as object, but also for the self as subject in the ascription of agency. We discuss and evaluate some proposals concerning the mechanisms involved in selfidentification and in agencyascription, and their possible impairments in pathological cases. We argue in favor of a simulation hypothesis that claims that actions, whether overt or covert, are centrally simulated (...) by the neural network, and that this simulation provides the basis for action recognition and attribution. (shrink)

A traditional view of perception and action makestwo assumptions: that the causal flow betweenperception and action is primarily linear or one-way,and that they are merely instrumentally related toeach other, so that each is a means to the other.Either or both of these assumptions can be rejected. Behaviorism rejects the instrumental but not theone-way aspect of the traditional view, thus leavingitself open to charges of verificationism. Ecologicalviews reject the one-way aspect but not theinstrumental aspect of the traditional view, so thatperception and (...) action are seen as instrumentallyinterdependent. It is argued here that a betteralternative is to reject both assumptions, resultingin a two-level interdependence view in whichperception and action co-depend on dynamicallycircular subpersonal relations and as a result may bemore than merely instrumentally interdependent. Thisis illustrated by reference to motor theories ofperception and control theories of action. (shrink)

and apply it to various examples of neural plasticity in which input is rerouted intermodally or intramodally to nonstandard cortical targets. In some cases but not others, cortical activity ‘defers’ to the nonstandard sources of input. We ask why, consider some possible explanations, and propose a dynamic sensorimotor hypothesis. We believe that this distinction is important and worthy of further study, both philosophical and empirical, whether or not our hypothesis turns out to be correct. In particular, the question of how (...) the distinction should be explained is linked to explanatory gap issues for consciousness. Comparative and absolute explanatory gaps should be distinguished: why does neural activity in a particular area of cortex have this qualitative expression rather than that, and why does it have any qualitative expression at all? We use the dominance/deference distinction to address the comparative gaps, both intermodal and intramodal. We do so not by inward scrutiny but rather by expanding our gaze to include relations between brain, body and environment. (shrink)

A physical model was utilized to show that the neural system can memorize a target position and is able to cause motor and sensory events that move the arm to a target with more accuracy. However, this cannot indicate in which coordinates the necessary computations are carried out. Turning off the lights causes the error to increase which is accomplished by cutting off one feedback path. The geometrical properties of arm kinematics and the properties of the kinesthetic and visual sensorial (...) systems should be better known before inferences about higher levels of processing can be drawn. (shrink)

RÉSUMÉLes qualia n'existent pas. La différence phénoménologique entre voir et imaginer, c'est que les propositions auxquelles l'expérient commence à croire dans le premier cas sont uniquement considérées dans le second. Nous pouvons savoir «quel effet cela fait d’être une chauve-souris» en sachant que leur faculté d’écholocation les informe non-inférentiellement des formes, grandeurs, et distances directionnelles des surfaces à proximité. Toutefois, les termes désignant les qualités secondes (comme les couleurs) sont les noms des propriétés-types qu'ils désignent, et dérivent causalement d'un «baptême» (...) verbal; les expérients ne peuvent donc connaître le caractère des expériences de couleur sans étudier la physiologie du cerveau. (shrink)

We present a model for several early stages of the sensorimotor transformations involved in targeted arm movement. In psychophysical experiments, human subjects pointed to the remembered locations of randomly placed targets in three-dimensional space. They made consistent errors in distance, and from these errors stages in the sensorimotor transformation were deduced. When subjects attempted to move the right index finger to a virtual target they consistently undershot the distance of the more distal targets. Other experiments indicated that the error was (...) in the sensorimotor transformation rather than in the perception of distance. The error was most consistent when evaluated using a spherical coordinate system based at the right shoulder, indicating that the neural representation of target parameters is transformed from a retinocentric representation to a shoulder-centered representation. According to the model, the error in distance results from the neural implementation of a linear approximation in the algorithm to transform shoulder-centered target parameters into a set of arm orientations appropriate for placing the finger on the target. The transformation to final arm orientations places visually derived information into a frame of reference where it can readily be combined with kinesthetically derived information about initial arm orientations. The combination of these representations of initial and final arm orientations could give rise to the representation of movement direction recorded in the motor cortex by Georgopoulos and his colleagues. Later stages, such as the transformation from kinematic to dynamic parameters, or to levels of muscle activation, are beyond the scope of the present model. (shrink)

Perceptual similarity is one of the most fiercely debated topics in the philosophy and psychology of perception. The documented history of the issue spans all the way from Plato – who regarded similarity as a key factor for human perceptual experience and cognition – through to contemporary psychologists – who have tried to determine whether, and if so, how similarity relationships can be established between stimuli both within and across the senses. Recent research on cross-sensory associations, otherwise known as crossmodal (...) correspondences – that is, the existence of observable consensual associations, or mappings, between stimuli across different senses – represents an especially interesting field in which to study perceptual similarity. In fact, most accounts of crossmodal association that have been put forward in the literature to date evoke perceptual similarity as a key explanatory factor mediating the underlying association. At the same time, however, these various accounts raise several important theoretical questions concerning the very nature of similarity, with, for example, the sensory, affective, or cognitive underpinnings of similarity judgements remaining unclear. We attempt to shed light on these questions by examining the various accounts of crossmodal associations that have been put forward in the literature. Our suggestion is that perceptual similarity varies from being phenomenologically-based to conceptually-based. In particular, we propose that the nature of the associations underlying similarity judgements – whether these associations are phenomenologically-, structurally-, emotionally-, or conceptually-based – may be represented in a two-dimensional space with associative strength on one axis, and cognitive penetrability on the other. (shrink)

Experience with inverting glasses reveals key factors of spatial vision. Interpretations of the literature based on the metaphor of a “visual image” have raised the question whether visual experience with inverting glasses remains inverted or whether it may turn back to normal after adaptation to the glasses. Here, I report on my experience with left/right inverting glasses and argue that a more fine-grained sensorimotor analysis can resolve the issue. Crucially, inverting glasses introduce a conflict at the very heart of spatial (...) vision. At first, the experience of visual direction grounded in head movements differs from visual experience grounded in eye movements. During adaptation, this difference disappears, and one may learn to see without conflict where objects are located (this took me 123 h of practice). The momentary experience became once again integrated within the larger flow of visual exploration involving head movements, a change of experience that was abrupt and comparable to a Gestalt switch. The resulting experience remains different from normal vision, and I argue that this difference can be understood in sensorimotor terms. I describe how adaptation to inverting glasses is further reflected in mental imagery, supporting the idea that imagery is grounded in sensorimotor engagement with the environment as well. (shrink)