Non-referring Concepts. Technical Report 2003-03
Non-referring concepts are mental representations of nonexistent things like dragons and time machines. Non-referring words are the words that express those concepts. In reference-based approaches to formal semantics, there is a well-known puzzle about how non-referring words and concepts get their meanings. The default solution is that they are special cases, with a different semantic structure from their referring counterparts. Despite over a century of debate in formal semantics, the issue of non-reference has, until now, been ignored in the psychological literature on concepts. But it is not obvious in advance what the psychological structure and processing of nonreferring concepts will be like. Furthermore, experimental evidence about non-referring concepts can help resolve issues fundamental to both semantics and psychology, such as the nature of meaning, the nature of concepts, and the debate over representational externalism. I used the methods of experimental psychology to provide the first empirical test of the claim that non-referring concepts are a special kind of concept. I found that nonreferring concepts have a very similar structure to referring concepts. This finding suggests that many popular versions of reference-based semantics are flawed, perhaps fatally. I also found that non-referring concepts take measurably longer to process than referring concepts. I argue that the best way of reconciling the second result with the first is to make a distinction between the knowledge that is constitutive of a concept and the knowledge that is external to it. Non-referring concepts are processed more cautiously because we know that their referents do not exist – a fact that is about the world rather than the concept itself. This distinction is consistent with the apparently contradictory evidence that motivates “Theory Theory” accounts of conceptual structure on one hand, and similarity-based accounts such as prototype and exemplar theories on the other. This dissertation concerns the following topic areas: cognitive psychology, cognitive science, concepts, empty names, externalism, internalism, mental representation, nonexistent objects, non-referring concepts, philosophy of language, philosophy of mind, prototypes, reference, semantics, similarity, and Theory Theory.