The semantic structure of Capgras' syndrome (CS) was analyzed within the framework of "the theory of reference" of analytic philosophy to elucidate the concept of misidentification in delusional misidentification syndromes (DMS). The close relationship between the semantic structure of CS and the ordinary use of a proper name, which is not synonymous with the description but has the function of indicating an object rigidly, is shown. CS is redefined from this perspective, and a novel misidentification symptom, which we call "clonal pluralization of a person", is contrasted to CS. Among so-called DMS, there are at least two types of misidentification with different semantic structures.