Abstract: In this paper, quantified modal logic is defended against criticisms concerning identity and substitution, the interpretation of the existential quantifier, and the commitment to essentialism. The paper includes two appendices: the first is a record of the discussion that followed the presentation of the paper in 1962, and includes Quine and Kripke among the discussants; the second is a review of A. Smullyan's “Modality and Description.”

Keywords: Barcan formula, description, essentialism, extensionality, identity, intensionality, Kripke, modality, proper names, quantified modal logic, Quine, Smullyan, substitutional quantification, tags,