How relevant is an individual difference theory of personality?

Doubts are raised as to the extent of "applicability of the conceptualization that "personality" consists "of more or less stable internal factors that make one person's behavior consistent from one time to another, and different from the behavior other people would manifest in comparable situations". This is done by demonstrating the questionable validity of much of the extant empirical support for the "personality" concept. Respondents on interpersonal checklists, personality inventories and questionnaire interviews are shown to unwittingly sub stitute a theory of conceptual likenesses for a description of behavioral co-occurrences. Considerations about similarity are confounded with judgments about probability to such an extent that items alike in concept are inferred to be behaviorally characteristic of the same person even when, as is typically the case, conceptual relationships among items do not correspond to the actual behavioral relationships among items. Examined are extant "personality theories" having to do with children's social behavior, adult behavior in small groups, maternal socialization practices, and psychopathology. These "theories" are shown to be no more than statements about how respondents (and psychologists) classify things as alike in meaning.