Systems Theory or Systems Science: A system is an entity with interrelated and interdependent parts; it is defined by its boundaries and it is more than the sum of its parts (subsystem)/ n a complex system (having more than one sub-system.) a change in one part of the system will affect the operation and output of other parts and the operation and output of the system as a whole, systems theory attempts to find predictable patterns of behavior of these systems, and generalizes them to systems as a whole. The stability, growth or decline of a system will depend upon how well that system is able to adjust or be adjusted by its operating environment

Niklas Luhmann-Social Systems Theory: distinction between system and environment (inside/outside)/ it is the communications between people not people themselves, they are outside the system/ our thoughts make no difference to society unless they are communicated/ systems communicate about their environments, not with them/ the environment is what the system cannot control/ systems relate to the environment as information and as a resource/ society-encounters-organizations: the three types of social systems.

Autopoiesis: literally means self-creation/ a system capable of reproducing and maintaining itself; it is autopoietic if the whole produces the parts from which it is made/

Society:  is an autopoietic system whose elements are communicative events reproducing other communicative events/ this communication has content and relationship levels: what is communicated and how/ all communication is both communication and communication about communication/ communication is imaginary/ communication takes place when an observer infers that one possible behaviour has been selected to express one possible message or idea/ the meaning of the message is always inferred by the observer.

Complexity: a system becomes complex when it is impossible to relate every element to every other element in every conceivable way at the same time/ when we can observe it in non equivalent ways/ when we can discern many distinct subsystems/ complexity is a property of observing 

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