Abstract

SummaryOne form of the principle of the identity of indiscernibles asserts that for any two distinct entities it is necessarily the case that there is a description which distinguishes between them, in that it applies to one but not to the other. In this paper it is argued that this form of the principle is false. The argument is based upon the nature of language, in particular the need for ostensive definition of terms which are not verbally definable. It is concluded that the identity of indiscernibles, in its linguistic form, requires a power of discrimination which no language could possess. Other versions of the principle, however, formulated in terms of properties rather than descriptions, are unaffected by the argument and may well be true.