Viable and Self-Replicating systems
There is a significant literature – Beer’s (1972) Viable Systems Model, Hitchins (2007) – on “viable systems”, using the term in the sense of “capable of existence and development as an independent unit”,
or “capable of surviving or living successfully, especially under particular environmental conditions”. Successful biological and organisational systems are viable in this sense. Viability in this sense is also a desirable attribute
of many engineered systems. Hence, we offer a definition:
A viable system is an open system that, within
certain environmental limits, can: sustain itself by exchanging matter, energy and information with its environment; detect and survive external threats; maintain and repair its internal organisation in the face of disruption; and adapt to a changing
environment (e.g. by evolving its capabilities); while maintaining its internal equilibrium (homeostasis).
Living systems, as well as being “viable”, are also self-replicating and capable of adaptation and evolution:
A self-replicating system is an open system that,
within certain lifecycle limits, can: reproduce itself by exchanging matter, energy and information either with its environment or with a second system of a compatible type; and pass on its attributes to the reproduced child system.
Beer S (1972) Brain of the Firm, Allen Lane, The Penguin Press, London, 1972