Because Cattell believes that we cannot define personality until we have fully specified all the concepts we plan to use in our endeavor, Raymond B. Cattell offers only the very general statement that "personality is that which permits a prediction of what a person will do in a given situation". He does, however, add that personality is concerned with all behavior, including what is concrete and observable and what may only be inferred, and he reminds us that the meaning of small segments of behavior can be fully understood only when seen within the framework of the entire functioning person. Like Gordon Allport, Cattell grounds his theory on the concept of trait; like William Sheldon, he strongly emphasizes the biological basis of behavior; and like Henry Murray, he explicitly gives a formal place in his scheme to both person variables and environment variables.
