Co-application, Identity, and Abstraction: A Note on Amie Thomasson’s Easy Ontology

Whereas neo-Fregeans, such as Hale and Wright, as well as other abstractionists, e.g., Linnebo, employ abstraction principles in their views of reference and objecthood—the idea being that abstraction principles ensure that a relevant term objectually refers—some recent developments, e.g., Schiffer’s and Thomasson’s, aim at avoiding them. The aim of this paper is to question the extent to which this is feasible. In the case of Thomasson, this question has to do with the notion of co-application conditions—that is, with “rules that (supposing the term to have been successfully applied) specify under what conditions the term would be applied again to one and the same entity” (Thomasson, 2007, 40). I argue that Thomasson’s characterisation of co-application conditions requires them to be stated via an abstraction principle. If this is correct, then it is not clear why Thomasson’s view has an advantage over its predecessors, which also reveals some further difficulties for the views under consideration.