Rigidity, natural kind terms and metasemantics

A paradigmatic case of rigidity for singular terms is that of proper names. And it would seem that a paradigmatic case of rigidity for general terms is that of natural kind terms. However, many philosophers think that rigidity cannot be extended from singular terms to general terms. The reason for this is that rigidity appears to become trivial when such terms are considered: natural kind terms come out as rigid, but so do all other general terms, and in particular all descriptive general terms. This paper offers an account of rigidity for natural kind terms which does not trivialise in this way. On this account, natural kind terms are de jure obstinately rigid designators and other general terms, such as descriptive general terms, are not.