Indiscernibility of identicals

Abstract

It is well known that the manner in which a definitely descriptive term contributes to the meaning of a sentence depends on the place the term occupies in the sentence. A distinction is accordingly drawn between ordinary contexts and contexts variously termed ‘non-referential’, ‘intensional’, ‘oblique’, or ‘opaque’. The aim of the present article is to offer a general account of the phenomenon, based on transparent intensional logic. It turns out that on this approach there is no need to say (as Frege does) that descriptive terms are referentially ambiguous or to deny (as Russell does) that descriptive terms represent self-contained units of meaning. There is also no need to tolerate (as Montague does) exceptions to the Principle of Functionality. The notion of an ordinary (i.e., ‘non-intensional’) context is explicated exclusively in terms of logical structure and it is argued that two aspects of ordinariness (termed ‘hospitality’ and ‘exposure’) must be distinguished.