touch 27 Thirrdly, the straining of the eye 28 The occasions which suggest distance have in their own nature no relation to it 29 A difficult case proposed by Dr. Barrow as repugnant to all the known theories 30 This case contradicts a ...

In this paper I will outline a unified information processing framework whose goal is to explain how the nervous system represents space, time and objects. In the remainder of this introductory section I will first be more specific about the sort of spatial, temporal, and object representation at issue, and then outline the structure of this paper.

I explain a strategy, called model-based control, which has proven useful in control theory, and argue that many aspects of brain function can be understood as applications of this strategy. I first demonstrate that in the domain of motor control, there is good evidence that the brain constructs models, or emulators, of musculoskeletal dynamics. I then argue that imagery, motor, visual and otherwise, can be supported by these emulatory mechanisms. I argue that the same apparatus to understanding aspects of psychological (...) development, including the development of theory of mind. I then show how features of linguistic competence can be addressed with the same mechanisms. Finally, I develop a semantic theory applicable to these emulators. (shrink)

"Perception is not something that happens to us, or in us," writes Alva Noe. "It is something we do." In Action in Perception, Noe argues that perception and perceptual consciousness depend on capacities for action and thought — that ...

[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. (shrink)

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. (shrink)

b>: In this article I outline, apply, and defend a theory of natural representation. The main consequences of this theory are: i) representational status is a matter of how physical entities are used, and specifically is not a matter of causation, nomic relations with the intentional object, or information; ii) there are genuine (brain-)internal representations; iii) such representations are really representations, and not just farcical pseudo-representations, such as attractors, principal components, state-space partitions, or what-have-you;and iv) the theory allows us to (...) sharply distinguish those complex behaviors which are genuinely cognitive from those which are merely complex and adaptive. (shrink)

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in (...) parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language. Key Words: efference copies; emulation theory of representation; forward models; Kalman filters; motor control; motor imagery; perception; visual imagery. (shrink)

The main idea of this book is that perceiving is a way of acting. Perception is not something that happens to us, or in us. It is something we do. Think of a blind person tap-tapping his or her way around a cluttered space, perceiving that space by touch, not all at once, but through time, by skillful probing and movement. This is, or at least ought to be, our paradigm of what perceiving is. The world makes itself available to (...) the perceiver through physical movement and interaction. In this book I argue that all perception is touch-like in this way: perceptual experience acquires content thanks to our possession of bodily skills. What we perceive is determined by what we do ; it is determined by what we are ready to do. In ways I try to make precise, we enact our perceptual experience; we act it out. (shrink)

The emulation theory of representation articulated in the target article is further explained and explored in this response to commentaries. Major topics include: the irrelevance of equilibrium-point and related models of motor control to the theory; clarification of the particular sense of “representation” which the emulation theory of representation is an account of; the relation between the emulation framework and Kalman filtering; and addressing the empirical data considered to be in conflict with the emulation theory. In addition, I discuss the (...) further empirical support for the emulation theory provided by some commentators, as well as a number of suggested theoretical applications. (shrink)

: Berkeley's Essay Towards a New Theory of Vision presents a theory of various aspects of the spatial content of visual experience that attempts to undercut not only the optico-geometric accounts of e.g., Descartes and Malebranche, but also elements of the empiricist account of Locke. My task in this paper is to shed light on some features of Berkeley's account that have not been adequately appreciated. After rehearsing a more detailed Lockean critique of the notion that depth is a proper (...) object of vision, Berkeley directs arguments he takes to be entirely parallel against the notion that vision has two-dimensional planar contents as proper objects. I show that this argument fails due to an illicit slide unnoticed by both Berkeley and his commentators—a slide present but innocuously so in the case of depth. Berkeley's positive account, according to which the apparent spatial content of vision is a matter of associations between, on the one hand, tactile and motor contents, and on the other hand non-spatial visual contents, also fails because of an illicit slide—again, unnoticed by Berkeley and his commentators. I close by discerning the salvageable and correct core of Berkeley's theory of the spatiality of vision. (shrink)

What is the relation between perceptual experience and the suite of sensorimotor skills that enable us to act in the very world we perceive? The relation, according to ‘sensorimotor models’ is tight indeed. Perceptual experience, on these accounts, is enacted via skilled sensorimotor activity, and gains its content and character courtesy of our knowledge of the relations between movement and sensory stimulation. I shall argue that this formulation is too extreme, and that it fails to accommodate the substantial firewalls, dis-integrations, (...) and specialpurpose streamings that form the massed strata of human cognition. In particular, such strong sensorimotor models threaten to obscure the computationally potent insensitivity of key information-processing events to the full subtleties of embodied cycles of sensing and moving. (shrink)