It has been suggested that the theory of reference advanced by Kripke and Putnam implies, or presupposes, an aristotelian vision of natural kinds and essences. I argue that what is in fact established is that there are degrees of naturalness among kinds. A parallel argument shows that there are degrees of naturalness among individuals. A subsidiary theme of the paper is that the definition of "natural kind term" as "rigid designator of a natural kind" is mistaken. Names and natural kind terms ar…
Read moreIt has been suggested that the theory of reference advanced by Kripke and Putnam implies, or presupposes, an aristotelian vision of natural kinds and essences. I argue that what is in fact established is that there are degrees of naturalness among kinds. A parallel argument shows that there are degrees of naturalness among individuals. A subsidiary theme of the paper is that the definition of "natural kind term" as "rigid designator of a natural kind" is mistaken. Names and natural kind terms are defined by ostension to a spatiotemporal part of what they ostend. This helps us understand why 'Hesperus' and 'Phosphorus' are cognitively non-equivalent
