According to JP Sartre, there is no such thing as an isolated individual. Robinson Crusoe was not isolated; he brought the values, customs and mores of his particular society with him to his lonely island.
The “individual” is best pictured as a nexus or node for a highly complex and frequently contradictory relationships with people, institutions, ideals, values, mores and particular objects (such as a car or watch).
The self is best pictured as the fascia or connective tissues that hold the diverse, highly complex and contradictory relationships in a relatively stable configuration.
The relationship of the self or fascia to the relationships that it holds in place is dialectical. The fascia of the hand holds the bones of the hand in place and makes possible the function of the hand as a hand. The fascia of the foot, while making it possible for the foot to function as a foot, will not help the hand function as a hand.
The fascia of the self, however, is not fixed. Rather its shape and design varies with the function and functioning of the diverse and contradictory relationships of the “individual” to its “objects” (ideals, values, morals, ambitions, skills, and particular material objects).
If the fascia of the self becomes rigid and/or calcified, any changes in the complex and contradictory relationships that it seeks to stabilize and hold in place will be experienced as painful.
If the fascia of the self becomes rigid or calcified it will not be able to develop in relation either to its internal impulses or relative to changes in the social sphere.
That the fascia of the self is capable of change or more properly of development makes the self susceptible to fragmentation or breaking up as previously concealed, for example, contractions between relations come to the fore. The fact that the fascia will fragment and break up on occasion does not mean however that, as some have concluded, that there is no self.
The capacity of the fascia (self) to withstand contradiction and the pains of development is dependent upon the biochemical makeup of the fascia. This make up and these elements remain and are continuous throughout the lifespan of the fascia. While then the fascia may break up or become rigid or change relative to development, the essential elements of the fascia do not break up or change. That iron may be liquid or rigid or appear in a variety of shapes does not mean that it is not iron.
Change does not mean development. A hand, for example, may be hit by hammer; this blow may permanently cripple the hand. The fascia of the self may calcify in a form of scar tissue. But just a blind person may correct to a degree for his or her blindness by the development of the other senses, so the fascia of the hand may correct or adjust to permit the hand a different form or kind of functionality.