According to Edgar Morin, a system can be conceived as the globally organised unity of interrelationships between elements, actions or individuals.
This definition is currently both comprehensive and innovative while it changes the way of thinking and seeing the system: from its components to its interrelationships.
The quality of a systems depends upon the quality of its internal and external links and is determined by its dynamics as a recursive combination of parts that are at the same time parts of a shared system and individual systems. Thus, a system is complex since it embraces all its parts (from the Latin meaning of complexity) and nested since it is located within other systems and contains elements that are entirely or partially embedded in the relationships within and outside its boundaries.
As Blaise Pascal wrote some centuries ago: "Since everything, then, is cause and effect, dependent and supporting, mediate and immediate, and all is held together by a natural though imperceptible chain which binds together things most distant and most different, I hold it equally impossible to know the parts without knowing the whole and to know the whole without knowing the parts in detail."
A system co-evolves and self-organises itself at the extent that the relationships allow a common life.
This means that a system has the property to be “autopoietic”. The term “autopoiesis” was coined by Maturana and Varela in the 1980’s, merging the Greek word poiesis (creation or production) and auto (self), in order to express the dynamics of the autonomy that characterises living systems.

The concept of autopoiesis was extended by Luhmann to social systems, denoting the capacity to be autonomous, self-propelled and self-contained by means of principles, codes and practices co-evolved within internal webs and external linkages. As it is for natural systems, social communities have fuzzy boundaries absorbing new energy and force from outside.