ABSTRACT
Some theoretical identity statements address concrete objects. An example of a theoretical identity statement about a concrete object suggested in the literature would be ‘Cicero = the organism descended from sperm s and egg e’, where ‘s’ and ‘e’ are names for the right sperm and egg. Not all identity statements widely accepted as necessary specify a theoretically interesting essence in the relevant respect. According to a tradition made familiar by Kripke and Putnam, scientists inquire into the nature of kinds that were named before much science was known. The literature on theoretical identity statements includes a discussion of many kinds of kinds. There has been increasing discussion over the years of human kinds, like woman, as well as institutional kinds like president, and the like. Theoretical identity statements about the essence of such kinds might be a priori for the same reason as theoretical identity statements about biological or chemical kinds.
