Glossary of systems theory

A glossary of terms as relating to systems theory.

A

 * Adaptive capacity: An important part of the resilience of systems in the face of a perturbation, helping to minimise loss of function in individual human, and collective social and biological systems.


 * Allopoiesis is the process whereby a system produces something other than the system itself.


 * Allostasis is the process of achieving stability, or homeostasis, through physiological or behavioral change.
 * Autopoiesis is the process by which a system regenerates itself through the self-reproduction of its own elements and of the network of interactions that characterize them. An autopoietic system renews, repairs, and replicates or reproduces itself in a flow of matter and energy. Note: from a strictly Maturanian point of view, autopoiesis is an essential property of biological/living systems.

B

 * Black box is a technical term for a device or system or object when it is viewed primarily in terms of its input and output characteristics.


 * Boundaries: The parametric conditions, often vague, always subjectively stipulated, that delimit and define a system and set it apart from its environment.

C

 * Cascading failure is failure in a system of interconnected parts, where the service provided depends on the operation of a preceding part, and the failure of a preceding part can trigger the failure of successive parts.


 * Closed system: A state of being isolated from the environment. No system can be completely closed; there are only varying degrees of closure.


 * Complexity: A systemic characteristic that stands for a large number of densely connected parts and multiple levels of embeddedness and entanglement. Not to be confused with complicatedness, which denotes a situation or event that is not easy to understand, regardless of its degree of complexity.


 * Culture: The result of individual learning processes that distinguish one social group of higher animals from another.  In humans culture is the set of products and activities through which humans express themselves and become aware of themselves and the world around them.

D

 * Development: The process of liberating a system from its previous set of limiting conditions. It is an amelioration of conditions or quality.


 * Dissipative structure: A term invented by Ilya Prigogine to describe complex chemical structures undergoing the process of chemical change through the dissipation of entropy into their environment, and the corresponding importation of “negentropy” from their environment. Also known as syntropic systems.

E

 * Embeddedness: A state in which one system is nested in another system.


 * Emergence: The appearance of novel characteristics exhibited on the level of the whole ensemble, but not by the components in isolation.


 * Enantiostasis is the ability of an open system, especially a living organism, to stabilize and conserve function in spite of an unstable environment.


 * Entanglement: A state in which the manner of being, or form of existence, of one system is inextricably tied to that of another system or set of systems.


 * Entropy: In physics, entropy is a measure of energy that is expended in a physical system but does no useful work, and tends to decrease the organizational order of the system.


 * Environment: The context within which a system exists. It is composed of all things that are external to the system, and it includes everything that may affect the system, and may be affected by it at any given time.


 * Evolution: A tendency toward greater structural complexity, ecological and/or organizational simplicity, more efficient modes of operation, and greater dynamic harmony. A cosmic process specified by a fundamental universal flow toward ever increasing complexity that manifests itself through particular events and sequences of events that are not limited to the domain of biological phenomenon, but extend to include all aspects of change in open dynamic systems with a throughput of information and energy. In other words, evolution relates to the formation of stars from atoms, of Homo sapiens from the anthropoid apes, and the formation of complex societies from rudimentary social systems.


 * Evolutionary Systems: A form of systems design that responds to the need for a future-Design (ESD) creating design praxis, that embraces not only human interests and life-spans, but those on planetary and evolutionary planes as well. The primary vehicle for the implementation of ESD is the Evolutionary Learning Community (ELC).

F

 * Feedback is a functional monitoring signal obtained from a given dynamic and continuous system. A feedback function only makes sense if this monitoring signal is looped back into an eventual control structure within a system. This monitoring shall be compared with a known desirable state. The difference between the feedback monitoring signal and the desirable state of the system gives the notion of error. The amount of error can guide corrective actions to the system in order to generate trends to bring the system gradually back to the desirable state.

H

 * Heterarchy: An ordering of things in which there is no single peak or leading element, and which element is dominant at a given time depends on the total situation, often used in contrast to hierarchy, also a vertical arrangement of entities (systems and their subsystems), usually ordered from the top downwards rather than from the bottom upwards.


 * Holarchy: A concept invented by Arthur Köestler to describe behavior that is partly a function of individual nature and partly a function of the nature of the embedding system, generally operating in a bottom upwards fashion.


 * Holism: A non-reductionist descriptive and investigative strategy for generating explanatory principles of whole systems. Attention is focused on the emergent properties of the whole rather than on the reductionist behavior of the isolated parts. The approach typically involves and generates empathetic, experiential, and intuitive understanding, not merely analytic understanding, since by the definition of the approach, these forms are not truly separable (as nothing is).


 * Holon (philosophy): A whole in itself as well as a part of a larger system.


 * Homeorhesis is a concept encompassing dynamical systems which return to a trajectory, as opposed to systems which return to a particular state, which is termed homeostasis.


 * Homeostasis is that property of either an open system or a closed system, especially a living organism, which regulates its internal environment so as to maintain a stable, constant condition.


 * Human Activity Systems: Designed social systems organized for a purpose, which they attain by carrying out specific functions.

L

 * Lowerarchy: A specific type of hierarchy involving a ‘bottom up’ arrangement of entities such that the few are influenced by the many.

M

 * Metastability is the ability of a non-equilibrium state to persist for some period of time.
 * Model building: A disciplined inquiry by which a conceptual (abstract) representation of a system is constructed or a representation of expected outcomes/output is portrayed.

O

 * Open system: A state and characteristics of that state in which a system continuously interacts with its environment. Open systems are those that maintain their state and exhibit the characteristics of openness previously mentioned.

P

 * Process is a naturally occurring or designed sequence of changes of properties or attributes of an object or system.
 * Process model: An organized arrangement of systems concepts and principles that portray the behavior of a system through time. Its metaphor is the “motion-picture” of “movie” of the system.

R

 * Reductionism: One kind of scientific orientation that seeks to understand phenomena by a) breaking them down into their smallest possible parts: a process known as analytic reductionism, or conversely b) conflating them to a one-dimensional totality: a process known as holistic reductionism.

S

 * Self-organization is a process in which the internal organization of a system, normally an open system, increases in complexity without being guided or managed by an outside source.


 * Self-organizing systems typically (though not always) display emergent properties.


 * Steady state is a more general situation than Dynamic equilibrium. If a system is in steady state then the recently observed behaviour of the system will continue into the future. In stochastic systems, the probabilities that various different states will be repeated will remain constant.


 * Strong emergence is a type of emergence in which the emergent property is irreducible to its individual constituents.


 * Subsystem: A major component of a system. It is made up of two or more interacting and interdependent components. Subsystems of a system interact in order to attain their own purpose(s) and the purpose(s) of the system in which they are embedded.


 * Suprasystem: The entity that is composed of a number of component systems organized in interacting relationships in order to serve their embedding suprasystem.


 * Sustainability: The ability of a system to maintain itself with no loss of function for extended periods of time. In human terms it is the creative and responsible stewardship of resources — human, Management natural, and financial — to generate stakeholder value while contributing to the well-being of current and future generations of all beings.


 * Synchrony: Also synchronicity. In engineering; concurrence of periods and/or phases; simultaneity of events or motions: contemporaneous occurrences. In evolutionary systems thinking; a fortunate coincidence of phenomenon and/or of events.


 * Synergy: Also system. Synergy is the process by which a system generates emergent properties resulting in the condition in which a system may be considered more than the sum of its parts, and equal to the sum of its parts plus their relationships. This resulting condition can be said to be one of synergy.


 * Syntony: In evolutionary systems thinking; evolutionary consonance; the occurrence and persistence of an evolutionarily tuned dynamic regime. Conscious intention aligned with evolutionary purpose; more loosely, the embodiment and manifestation of conscious evolution; a purposeful creative aligning and tuning with the evolutionary flows of one’s milieu. In traditional radio engineering; resonance.


 * Syntropy The process of negentropy-importation. A syntropic system is a dissipative structure.


 * Systems design A decision-oriented disciplined inquiry that aims at the construction of a model that is an abstract representation of a future system.


 * Soft Systems Methodology:

W

 * Weak emergence is a type of emergence in which the emergent property is reducible to its individual constituents.


 * White box is a technical term for a device or system analyzed or tested based on knowledge of its internal structure (compare to Black box).


 * Wholeness: In reference to systems, the condition in which systems are seen to be structurally divisible, but functionally indivisible wholes with emergent properties.