Successful psychotherapy depends on the presence of an essential cognitive element that determines its course. The origin of the structure and function of this element depends upon biological and social factors present during the developmental years. The maturity of the element occurs with biological maturity of the person. Its functioning in the process of psychotherapy depends upon the freedom of the person seeking help to participate actively and to have some responsibility for direction. Three identifiable stages characterize its function. Distinct structural fundamentals define each stage: 1) Perceptual-Explorative, trial-and-error behavior, 2) Provenience-Causative, perceptual distortion and search for origin or cause of the problem, and 3) Hypothetico-Deductive, development of hypotheses leading to solution. Attention to this essential element reveals points of