Disambiguating the Perceptual Assumption

Deroy and Auvray together with Ptito et al. have argued against what they dub ‘the perceptual assumption’, which they claim underlies all previous research into sensory substitution devices (SSDs). In this chapter, I argue that the perceptual assumption needs to be disambiguated in three distinct ways: (A) SSD use is best modelled as a known, ‘natural’ modality; (B) SSD use is best modelled as a unique sensory modality full stop; and (C) SSD use is best modelled as a perceptual process. Different theorists are variously committed to these distinct claims. More importantly, evaluating A, B, or C for rejection depends on distinct evidence of difference between SSD use and (A) each natural modality, (B) any modality, and (C) perceptual processing. I argue that even if the offered evidence of difference for A–C is granted, Auvray and Deroy’s advocated rejections are not entailed; it remains to be shown that the identified differences undermine the appropriate use of the corresponding models.