Being Sceptical about Kripkean A Posteriori Necessities and Natural Kinds

Abstract

The article discusses Saul Kripke’s influential theories of a posteriori necessary truths and natural kinds. With respect to the statements of identity involving proper names, it is argued that although their truth is a posteriori and necessary in the specific sense of counterfactual invariance, this is of no significance for substantial philosophical issues beyond the philosophy of language, because this counterfactual invariance is a trivial consequence of the use of proper names as rigid designators. The case is made that the expansion of the realm of necessary a posteriori truths to the statements of theoretical identity that involve “natural kind terms”, as well as the Kripkean essentialist theory of natural kinds, have no weighty argumentative support and fit badly both with science and language practice. This sets the stage for the development of an appropriately sophisticated “descriptivist” account of meaning and reference that would be better suited for a widened range of Kripke-Putnam style thought experiments. The general outlines of such a descriptivist account are provided.