Individuating the Senses of ‘Smell’: Orthonasal versus Retronasal Olfaction

Abstract

The dual role of olfaction in both smelling, via orthonasal olfaction, and tasting, or flavour perception, via retronasal olfaction makes it an interesting test case for philosophical theories of sensory individuation.

Indeed, Rozin’s (1982) claim that olfaction is a “dual sense” has led some scientists and philosophers to suggest that we have not one, but two distinct senses of smell. In this paper I consider how best to understand Rozin’s claim, and upon what grounds one might judge there to be one or two olfactory modalities. I conclude that while Rozin may be right that humans have two token olfactory ‘senses’, the concept of a sense-modality, and hence the ‘sense’ of smell, is ambiguous between two distinct notions: a physiological sensory channel and an experiential modality, along the lines suggested by J. J. Gibson (1966).

Furthermore, recognising that these are not competing, but complementary conceptions of a sense-modality enables the formulation of a powerful ‘dual-concept’ framework for posing and addressing questions about the complex nature of multisensory experience.