Are Proper Names Rigid Designators?

A widely accepted thesis in the philosophy of language is that natural language proper names are rigid designators, and that they are so de jure, or as a matter of the "semantic rules of the language." This paper questions this claim, arguing that rigidity cannot be plausibly construed as a property of name types and that the alternative, rigidity construed as a property of tokens, means that they cannot be considered rigid de jure; rigidity in this case must be viewed as a pragmatic and not a semantic property.