The authors, one a social psychologist, the other a mathematician, have developed a formal axiom system which has as its 'primitives' abstractions of the entities involved in the foundation of ego development, as described in Instincts and Their Vicissitudes. The mathematics they use is the theory of balance in signal graphs and they show how diagrams may represent various stages of ego development. They derive various stages of ego development from simple axioms and 'in accordance with a procedural theorem derived from postulated tendencies toward balance and toward clustering'.