The logical form of structured propositions.

摘要

One of the main criteria for an adequate semantic theory is that it solve the problem of substitution into intensional contexts, otherwise known as Frege's Puzzle. Given common-sense assumptions about how natural language functions, a contradiction arises in explaining attitude reports. For example, Lisa might believe that Twain is tall, but not believe that Clemens is tall. Lisa is perhaps unaware that the names “Twain” and “Clemens” corefer. But Twain's being tall is just Clemens' being tall, so one and the same state of affairs is either believed or not. The tasks are to specify what Lisa believes and to accurately and consistently describe the situation given certain foundational semantic principles.; I argue that of three main semantic frameworks: Davidsonian Semantics, Model-Theoretic Semantics and Propositional Semantics (PS), PS has the best chance to provide a complete, consistent and natural solution. On my view, dynamic propositions (DP's) are complex states of affairs where things stand in the propositional relation of having expressions of a certain type which pick them out as semantic values and where those expressions stand in appropriate syntactic relations. The propositional relation crucially involves restricted quantification over expression types which are logical features of the language. The sentences “Twain is tall” and “Clemens is tall” express different DP's because even though their constituents are identical, they stand in distinct propositional relations in virtue of the different syntactic expressions. This explains how Lisa could believe one and not the other. These fine-grained propositions successfully serve as both the truth-conditions of sentences and the objects of propositional attitudes. The solution leads to the surprising result that the question of whether singular terms are Fregean or directly referential is actually irrelevant to Frege's Puzzle.; While DP's are naturalistic and theoretically well-motivated, they face apparent difficulty accounting for translation and being the objects of mental content. The logical form of DP's limits their possible interpretation and thus sheds light on the conceptual framework of its user. I argue that DP's are not beliefs, but cognitive models that serve as interpretations of beliefs in communication.