We now introduce our preferred terminology to distinguish between naturally occurring and human-made systems, while noting that many systems are a hybrid of the two, so this is not a binary classification.
A natural system is a system that occurs in nature without intervention by human agents.
Natural systems exhibit properties such as viability, resilience, and self-organisation that offer exemplars for engineered systems. Biomimicry refers to the practice of using natural systems as patterns for artificial ones.
An artificial system is a system constructed by human agents, or otherwise caused by them to come into being.
Human agents can be humans, or they can be processes, methods or tools created by humans that effect change indirectly to create the artificial system.
A hybrid system is a system with both natural and artificial elements, or a natural system influenced (e.g. by selective breeding) or modified (e.g. by genetic engineering) by intentional agents.
An engineered system means a system – artificial or hybrid, conceptual and/or physical –
that was properly systems-engineered in the sense of the definition.
Otherwise, a human-made system is artificial or hybrid, but not engineered. Of course, there can be the case of a badly engineered system – such as a system where the operational environment is not well anticipated and the “applicable
constraints” poorly selected.