Abstract

This is the most recent edition of Sameness and Substance, a version of which actually appeared even earlier as Identity and Spacio-Temporal Continuity of 1967. The main thesis of the work is that identity—along with the correlative concepts of substance and being the same particular, or more generally of being the same a as b—depends on the specification of the sort of thing instantiated by a and b. Wiggins calls this the “sortal dependency” thesis: in the case of an identity of a and b, it is only correct to say a is the same f as b, where f is a certain predicate applicable to both a and b. Wiggins develops, in other words, Wittgenstein’s suggestion in the Tractatus—the identity symbolized in an equals sign, such as a = b, is meaningless unless it means simply f & f. An addition to this developing work of special note is the new chapter on personal identity.