5 Language n the course of the nineteenth century, philosophers turned their attention ever more intensely on the topic of meaning What words and sentences signify? How they signify and they all signify in the same way? What is the relationship between meaning and truth? These questions were now asked with an urgency that had not been felt since the Middle Ages.1 I Frege on Sense and Reference A seminal work in the theory of meaning was Frege’s paper of 1892, ‘Sense and Reference’ That paper starts from a question about statements of identity Is identity a relation? If it is a relation, is it a relation between signs or between what signs stand for? It seems that it cannot be a relation between objects that signs stand for, because if so, when ‘a ¼ b’ is true then ‘a ¼ a’ cannot differ from ‘a ¼ b’ On the other hand, it seems that it cannot be a relationship between signs, because names are arbitrary, and if a sentence of the form ‘a ¼ b’ expressed a relationship between symbols it could not express any fact about the extra-linguistic world Yet a sentence such as ‘The morning star is identical with the evening star’ expresses not a linguistic tautology, but an astronomical discovery Frege solved this problem by distinguishing between two different kinds of signification Where other philosophers talk of meaning, Frege For medieval theories of meaning, see vol II, pp 130–1, 146–7