BRUTE FACTS, THE NECESSITY OF IDENTITY, AND THE IDENTITY OF INDISCERNIBLES

Abstract

In ‘Two Spheres, Twenty Spheres, and the Identity of Indiscernibles,’ Della Rocca argues that any counterexample to the PII would involve ‘a brute fact of non-identity [. . .] not grounded in any qualitative difference.’ I respond that Adams's so-called Continuity Argument against the PII does not postulate qualitatively inexplicable brute facts of identity or non-identity if understood in the context of Kripkean modality. One upshot is that if the PII is understood to quantify over modal as well as non-modal properties, the qualitative explicability of numerical distinctness requires not the PII but a principle of the identity of necessary indiscernibles.