# Sensory Substitution and Perceptual Emergence **Keywords:** — Sensory substitution, perceptual emergence, basic energy, perceptual modalities, endogenous contributions to perception. Sensory substitution devices (SSDs) can be thought of as sensory prosthetics — as devices by which information represented by one perceptual modality (the substituted modality) is instead represented by an alternative, non-canonical representational channel involving a second perceptual modality (the substituting modality). The hope is that such devices might aid subjects wi **Abstract:** Sensory substitution devices (SSDs) can be thought of as sensory prosthetics — as devices by which information normally represented by one perceptual modality is instead represented by an alternative, non-canonical channel involving a second perceptual modality. Given that sensory modalities ordinarily represent a very wide range of properties/events, it is no trivial matter to ensure that such prosthetic devices will capture the representational scope of the systems they aim to replace. Designers of such devices have often hoped to solve this challenge by building SSDs that succeed in representing the form(s) of basic energy normally represented by the impaired modality they are intended to replace, and then adding computational power to code up whatever can be derived from the basic energy. Thus, for example, the thought is that if we could build a device that represents in some alternative way 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 vision can represent: color, shape, form, motion, and so on. Unfortunately, I will argue, this attractively simple idea fails. For there appear to be features represented by our sensory modalities that are “perceptually emergent” — i.e., features whose exemplification is not fixed by the representation of the distribution of (the relevant forms of) basic energy. Hence, a SSD whose basic representational vocabula **Authors:** [[Jonathan Cohen∗]]