Systems theory is a conceptual framework that studies systems as they relate to one another within a larger, more complex system. The key concept of systems theory is that the whole is greater than the sum of its parts.
Systems theory is based on the principle that the component parts of a system can best be understood in the context of the relationships with each other and with other systems, rather than in isolation.
Systems theory can be used to analyze any system - including theological and church systems. It is particularly helpful for the pursuit and study of Catholic Social Teaching.
This Video on Systems Theory helps to illustrate that which was put forth by psychologist Edwin Friedman. His focus was on leadership and systems of leadership, but his analysis has other applications. Catholic Social Teaching is one example.
This PDF file below the video contains some slides that include references to the above video, and further explores Systems Thinking.
The Video: