The theory of generative grammar in linguistics is pursuing scientific explanation by setting up phrase structure rules to derive deep structure strings which are transformed into surface structure utterences. The whole process involves the deductive-nomological model. There are two approaches to semantic analysis for explanation: logical and psychological. The logical position of semantics aims at the characterization of the notions of truth of a sentence relative to a model and of entailment between sentences. It is concerned with formal precision, consistency and elegance, not with psychological processes. The psychological position, on the other hand, tries to treat meaning in terms of all aspects of cognition. For the most satisfactory explanation of semantic phenomena, both positions are necessary and must be synthesized or integrated.