Closed system

An open system can be influenced by events outside of the declared boundaries of a system. A closed system is self-contained: outside events can have no influence upon the system.

In practice many things are a mixture of the two. For example, a government is a closed system when it seeks to maintain confidentiality. However, it is open when it seeks advice and accepts universal voter input and petitions.

Dynamic systems have components or flows or both, that change over time.