Self-actualization is a term that has been used in various psychology theories, often in slightly different ways. The term was originally introduced by the organismic theorist Kurt Goldstein for the motive to realize one's full potential. In his view, it is the organism's master motive, the only real motive: "the tendency to actualize itself as fully as possible is the basic drive...the drive of self-actualization." Carl Rogers similarly wrote of "the curative force in psychotherapy - man's tendency to actualize himself, to become his potentialities...to express and activate all the capacities of the organism." However, the concept was brought most fully to prominence in Abraham Maslow's hierarchy of needs theory as the final level of psychological development that can be achieved when all basic and mental needs are fulfilled and the "actualization" of the full personal potential takes place.