A "System" is a somewhat vaguely-defined term. Some say anything composed of >1 interacting parts are "systems". Others have higher thresholds. Some say systems are mental constructs, others say they only exist in the real world. Long story short, the definition sucks, is abstract, and arguable in every instance. One very pragmatic definition I like: > Any set of related parts for which there is sufficient coherence between the parts to make viewing them as a whole useful. > _- [[Systems Engineering Book of Knowledge|SEBoK]] pg 95_ There's also a [[Systems Poem]] written by an economist. Another definition: > A regularly interacting or interdependent group of items forming a unified whole > _- Webster's New Collegiate Dictionary_ # Features of Systems - Systems may be **Open (interacting with an environment)** or **Closed**. - They may be **natural** or **man-made**. - Systems have (and are arguably defined by) **boundaries**. - Systems have a **purpose**, a reason for existing. - They have components. They contain connections between these components. - They often have [[System Stocks]], which are subject to flows into, out of, or within the system. Systems exhibit [[System Complexity]] and [[Emergent Behavior]]. Patterns of behavior occur within systems that are not attributable to any one component, but only emerge out of the interactions between them. These types of [[Pattern]]s may be common to different types of systems. These are called _archetypes_ in [[Systems Thinking]] parlance. One example of a common system archetype that forms across all types of domains is that of the [[Hierarchy]]. Problems that exist across one hierarchy often will show up across others. ![[screenshot 1.png]] **** # More ## Source - [[Systems Engineering Book of Knowledge]] - [[Thinking in Systems]] - [[Just Enough Structured Analysis]] ## Related - [[Systems Thinking]] - [[Systems Engineering]] - [[Elegant Systems in SE]] - [[General Systems Principles]]