Sortals, Natural Kinds and Re-Identification

Abstract

Investigations into the logical structure underlying ordinary language and our common sense framework have tended to support the hypothesis that there are different stages of conceptual involvement and that while the structures elaborated at a later stage are in general not explicitly definable or reducible to those at the earlier they nevertheless presuppose them as conceptually prior bases for their own construction and elaboration-even when these conceptually prior structures are somehow eliminated or completely reconstructed at the later stages. This applies, moreover, not just to the conceptual structures underlying our common sense framework but to those underlying the development of logic, mathematics and the different sciences as well.