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)

I support Pylyshyn's skepticism that visual imagery reflects a re-activation of the spatial layout of active neurons embedded within a topographical cortical map of visual space. The pickup of visual information via successive eye movements presents one problem and the two visual systems model poses another difficulty.

images. But clearly, it only begs the deeper questions.

In their study of reasoning with diagrammatic and non-diagrammatic representations, Larkin and Simon (1987) are concerned with _external_ representations and explicitly avoid drawing inferences about the bearing of their work on the issue of internal, mental representations. Nonetheless, we may infer the bearing of their work on internal representations from the theories of Kosslyn, Finke and other ‘pictorialists’ who take internal representations to be importantly like external ones regarding their ‘privileged’ spatial properties of depicting and resembling their referents. Thus, Finke (...) (1990) suggests that “perceptual interpretive processes are applied to mental images in much the same way that they are applied to actual physical objects. In this sense, imagined objects can be “interpreted” much like physical objects” (1990, p. 18). Elsewhere he suggests that “The image discoveries which then ‘emerge’ resemble the way perceptual discoveries can follow the active exploration and manipulation of physical objects” (1990, p. 171). (shrink)