There are three pillars for systems (as best described in the book Thinking in Systems by Donella H. Meadows) Resilience, Self-Organization, and Hierarchy.
Resilience refers to the system ability to survive and thrive within a continuously changing environment. Resiliency is critical for systems to exist over time.
Self-organization is the ability of the system to learn, create, design and evolve based on feedback. This ability enables systems to keep on adapting to the continuously growing complex environment. Self-Organization allows the system to be more complex. Self-organization requires giving freedom and experiment to parts of the system.
Hierarchy in systems thinking refers to the idea of fractals or containing. Systems composed from sub-systems that split to sub-sub-system that are broken to …. You got the idea. For many of us, hierarchies associate with power and rank, and that is NOT the intent.
Therefore I changed Hierarchy to structure when I interact with people. System, by the way, can have a different structure. Although the structure of containing sub-element is the most common one and depict in the concept of fractals as well, there are other structures as well.