Abstract

Synesthesia is a neurological phenomenon in which a single stimulus typically associated with one sensory modality automatically and involuntarily produces sensations not typically associated with that modality. I argue that synesthesia elucidates how two naturalistic theories of representation and phenomenal experience conflict. Strong representationalism holds that what an experience is like is determined by the experience’s representational content. Informational semantics holds that representational content is determined by causal co-variation between a representation and an external object or property. I argue that according to informational semantics, synesthetes and normal perceivers represent the same content in different ways. However, according to strong representationalism, two experiences with the same content must be represented in the same way. Therefore, if strong representationalists want to account for synesthesia, they cannot hold onto informational semantics as a theory of mental content.