Is the Visual World a Grand Illusion? by Alva Noë

In the past decade, the notion of a neural correlate of consciousness (or NCC) has become a focal point for scientific research on consciousness (Metzinger, 2000a). We do so not by inward scrutiny but rather by expanding our gaze to include relations between brain, body and environment. 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. ) the distinction should be explained is linked to explanatory gap issues for consciousness. 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.

We ask why, consider some possible explanations, and propose a dynamic sensorimotor hypothesis. In some cases but not others, cortical activity ‘defers’ to the nonstandard sources of input.

( shrink)Īnd apply it to various examples of neural plasticity in which input is rerouted intermodally or intramodally to nonstandard cortical targets.

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. 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. The experience of seeing occurs when the organism masters what we call the gov- erning laws of sensorimotor contingency. The out- side world serves as its own, external, representation. Activity in internal representations does not generate the experience of seeing.

It is a particular way of exploring the environment. 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. The activation of this internal representation is assumed to give rise to the experience of seeing. 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.

Is the Visual World a Grand Illusion? by Alva Noë