One way to evaluate a psychoanalytic theory is to picture a therapist with that theory in his mind and imagine what happens when we fold him into the basic soup of psychoanalytic procedure. Because the background forces of analytic treatment are so influential, the practical outcome cannot be predicted from the details or the validity of the theory alone. Thus, we should not assume that newly discovered items of neurophysiology and infant observation are ever what is actually being dealt with in psychoanalysis. To illustrate this principle, I select two recent theories derived from observational studies, and explore the likely effects that a therapist' belief in them would have on seven dimensions of the psychoanalytic situation. Theories set the therapist's attitude, the attitude affects the background forces, and the total effect of all of that constitutes the significance of the theories for psychoanalytic treatment.