ABSTRACT
The chapter begin with a very short course on modality: Possibility, necessity, actuality and contingency. Frege and Russell can be thought of as having agreed that for any ordinary proper name N, it means on the particular occasion of its use or understanding some definite description of the form the F. Kripke poses four problems with this: If N means the F then (1) it is necessary that N is the F; (2) it is a priori that N is the F; (3) it is analytic that N is the F; (4) one can understand sentences containing N only if one accepts N = the F. None of these holds. Kripke provides a causal-historical alternative to the descriptive theory of names, according to which names are rigid designators. Rigid designators are terms which always refer to the same object in every possible world (so long as the object exists). Intensional semantics is an attempt to explain meaning via the concept of possibility. The trouble is that it is implausible to say that knowledge of its truth-value in every possible world is sufficient for knowledge of the meaning of a sentence, since for example not all necessary truths are synonymous.
