I first encountered systems theory while studying family therapy. In its broadest sense, systems theory has to do with mathematics and physics. But there are several schools of family therapy and marriage counseling that use the concept.
The idea is that a system is a boundary-maintaining complex of relationships. In marriage therapy, for instance, the idea is that neither the husband or the wife is the patient, but the relationship is the patient. This can be expanded to large families and even to organizations. There are, however, several divergent schools of family therapy.
Systems thinking was at the heart of my training as an interim pastor. My trainers treated religious congregations as systems of relationships. Borrowing from family therapists Murray Bowen and Rabbi Edwin Friedman, the idea was for the interim minister to be a “non-anxious presence” in order to help congregations break out of screwed up patterns. It is similar to the way you can sometimes fix a computer by resetting it or adding a component without dealing with the individual components. This works because the computer is a system.
Anyway, this way of thinking counteracts the individualistic way of thinking many of us adopt. It is very hard to break the idea that a family or organization malfunctions because some individual in it is acting like a brat. Rather the whole system may have gone off course so that the bratty behavior now works within that system. But once you recognize systems, you stop trying to save individuals and concentrate on the connections.
I suggest that understanding the Bible in a less individualistic way might radically change our religion. Is God really trying to save us as individuals? Or is the Messiah a presence meant to modify the system? Or is it some of both?