This concept is the cornerstone in the theory. It defines people according to the degree of “fusion” between the emotional and intellectual functioning of the individual. This is a relative term, though Bowen established a theoretical scale of 0-100 in order to reflect on differences in individuals. Those people who are at the lowest end of the scale (less differentiated) are so fused in their emotional and intellectual functioning that their lives are dominated and controlled by the automatic emotional system. These are the people who are less flexible, less adaptable, and more emotionally dependent on those about them. At the high end of the scale are those people who are better differentiated. They are clear on what is intellectual functioning and what is emotional functioning. These are the people who maintain autonomy in times of stress, are more flexible, more adaptable and more independent of emotionality about them. They cope more successfully with life stresses, and life courses more orderly, more successfully and are freer of human problems. Another important part of the differentiation of self has to do with levels of “solid-self” and “pseudo-self.” The solid-self is based on clearly defined beliefs, opinions, convictions, and life principles. These are developed by the self over time and are based on intellectual reasoning. When making choices the solid-self accepts responsibility for the choices he makes. The pseudo-self is based on emotional pressures and changes with emotional pressures. The pseudo-self is composed of a group of principles, beliefs, philosophies, and knowledge, often acquired as group pressure dictates. Therefore, these principles and beliefs are often inconsistent and random. The individual is never aware of the inconsistencies. Thus, the persons can pretend to be in harmony with many and varied groups. An example of the pseudo-self is a marriage where spouses become a “we-ness." They seek togetherness. Generally, the spouses fuse into each other. One will gain self while the other loses self. When the relationship becomes fixed with one partner gaining self and the other losing self in a rigid manner, dysfunction results. They tend to be vulnerable to minor stresses with prolonged recoveries. These are the people who inherit a high number of human problems