Sensory Substitution and Perceptual Emergence

Abstract

Designers of sensory substitution devices (SSDs) typically aim to capture a wide representational scope by requiring their devices to present in the substituting modality the full range of basic energy available to the substituted modality, and then using this information to code up any further representations needed. On this view, if we could build a device that represents to touch (say) the distal distribution of light intensity—the basic form of energy to which visual receptors are normally responsive—our device could, in principle, represent everything available to vision: colour, shape, form, motion, and so on. Unfortunately, I will argue, this simple idea fails. For perceptual modalities represent ‘emergent’ features —i.e. features whose exemplification is not fixed by the representation of the distribution of basic energy. Hence, an SSD whose basic representational vocabulary is limited to the distribution of such basic energy will leave things out. None of this shows that SSDs will inevitably fail to represent what sensory modalities normally represent. It does suggest, however, that if we want them to represent what sensory modalities normally represent, we will have to do more than preserve the representation of basic energy to which the substituted modalities are sensitive.