Theories of natural kind term reference and empirical psychology.

In this paper, I argue that the causal and description theories of natural kind term reference involve certain psychological elements. My main goal is to refine these theories with the help of empirical psychology of concepts, and to argue that the refinement process ultimately leads to the dissolution of boundaries between the two kinds of theories. However, neither the refined theories nor any other existing theories provide an adequate answer to the question of what makes natural kind terms rigid. To provide an answer to this question I conclude my paper by introducing a framework of a unified theory of natural kind term reference that is built on the empirical psychology of concepts. [ABSTRACT FROM AUTHOR]