Syntax puts our meaning ("semantics") into sentences, and phonology puts the sentences into the sounds that we hear and there must, surely, be a structure in the meaning that is expressed in the syntax and phonology. Some writers use the phrase "semantic structure," but are referring to conceptual structure; since we can express our conceptual thought in many different linguistic ways, we cannot equate conceptual and semantic structures.
The research reported in this book shows semantic structure to be in part hierarchic, fitting the syntax in which it is expressed, and partly a network,...