Rigid Application, Theoretical Identifications and Metaphysical Necessity

ABSTRACT Saul Kripke introduced the notion of rigid designation for singular terms to disprove the description theory of meaning for names, and to argue that true identity statements with rigid designators are necessarily true, although a posteriori. He proceeded to apply the notion to general terms for natural kinds, stuffs and phenomena, and claimed that true theoretical identifications with rigid general terms are also necessary a posteriori truths. Michael Devitt pointed out that, regardless of whether general terms are taken to designate their extensions or abstract entities, rigid designation cannot single out the terms Kripke considered rigid. Devitt suggested that, in the case of general terms, rigid designation should be replaced with a notion of rigid application, where rigid appliers stand for essential properties. He showed that rigid application allows for creating ‘lost rigidity arguments’ against description theories of meaning for natural kind terms, but that it cannot ensure the necessity of true theoretical identifications with rigid appliers. In this paper, I will argue that necessitism, that is, the claim that anything which exists in any possible world exists in every possible world, is both necessary and sufficient to bridge the gap between rigid application and metaphysical necessity.