General systems theory is known by several names - systems theory, theory of open systems, systems model, family systems theory. The author of systems theory was Ludwig von Bertalanffy in the 1930’s. A system is a complex of elements in interaction, which on first appearance does not seem interconnected or related.  

Picture a baby’s mobile hanging above the crib. If you focus on the black and white cow only, the other parts of the mobile do not appear related. But if you pull on the cow’s leg, all parts including the brown cow, the moon, the star, and the heart all begin to move too. By suddenly letting go of the cow’s leg, all parts are in motion, bumping into one another. When the black and white cow moves up, the brown cow moves down--to accommodate their movement, the moon and heart move sideways.

Movement continues for a long time until they all look still; although motionless, all parts are positioned differently from the first time you saw them. The slightest current of air can change the shape of the mobile again.

OK, the mobile represents a system. Let’s translate our baby’s mobile to a patient situation. Our primary focus on the black and white cow can translate to be an AIDS patient—the system of concern having boundaries between internal and external environments. Within the internal and external environments are the other elements of the system. Those elements in the AIDS patient’s internal environment (mind, body, spirit) are called sub-systems. Those elements in the AIDS patient’s external environment are called supra-systems. Input and output from both internal and external environments are free-flowing, thus called an open-system. Free energy needed for self-regulation is called negentropy; entropy, on the other hand, is bound energy and not free for use. Negative and positive feedback is information coming into the system that affects its balance.

Physically, mentally, and spiritually, the AIDS patient receives input and feedback to realize that his internal systems (sub-systems) have changed and are less vital and not regenerating (entropy). His supra-system includes his single parent mother (brown cow), his advanced practice nurse (APN)(star), his significant other (heart), and his physician (moon).

This same system can be applied on a larger scale, since systems explain individuals, families, communities, and cultures. On a community scale, AIDS and gay rights groups represent the black and white cow, the American Nurses Association represents the APN (brown cow), disapproving religious groups (moon), and the American Medical Association (star). When the issue of assisted suicide is desired by the system (a topic we are focusing on in Module 2), the internal and external environments play major roles in how the system relates with its sub-and supra-systems.

Systems theory is a grand theory that has a wide scope and many applications. Begin by reviewing your reading about systems theory in the Friedman text (chapter 7). Note the family applications of systems theory. Here are a few classic references if you need to read further about systems theory.

Barnum, B.J.S. (1994). Nursing Theory: Analysis, application, and evaluation (4^th ed.). Philadelphia, PA: J.B. Lippincott.

Bertalanffy, L. von. (1968). General systems theory: Foundations, development application, rev’d ed. New York: George Braziller.

Chinn, P.L. (1979). Practice oriented theory: Part 1. Advances in Nursing Science, 1(2), 41-52.

Hazzard, M.E. (1971). An overview of systems theory. Nursing Clinics of North America, 6(3), 385-393.

Werley, H.H. et al. (Eds.). (1976). Health research: The systems approach. New York: Springer-Verlag.