Abstract

This paper challenges the Kripke-Putnam thesis about natural kind terms, according to which natural kind terms are referential and rigid. I argue that natural kind terms are semantically underdetermined expressions, and are therefore intrinsically neither referential nor rigid. After reviewing Kripke’s and Putnam’s original arguments, I look at examples of natural kind terms discussed by them and others in the literature, aiming to show that they are indeed semantically underdetermined. I conclude that contextualist considerations should be taken into account to explain the differing truth-conditional values these expressions may have. In Spanish.