Kripke on epistemic and metaphysical possibility: Two routes to the necessary aposteriori

Saul Kripke’s discussion of the necessary aposteriori in Naming and Necessity and “Identity and Necessity” -- in which he lays the foundation for distinguishing epistemic from metaphysical possibility, and explaining the relationship between the two – is, in my opinion, one of the outstanding achievements of twentieth century philosophy.1 My aim in this essay is to extract the enduring lessons of his discussion, and disentangle them from certain difficulties which, alas, can also be found there. I will argue that there are, in fact, two Kripkean routes to the necessary aposteriori – one correct and philosophically far-reaching, the other incorrect and philosophically misleading.