System

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System (from Ancient Greek σύστημα "a whole compounded of several parts; a connection") is a set of elements in relationships and connections with each other, which forms a certain integrity, a unity.[1]

The need to use the term "system" arises when it is necessary to emphasize that the object under consideration is large, complex, and not immediately fully understood, yet represents something whole and unified. Unlike the concepts of "set" or "collection," the concept of a system emphasizes orderliness, integrity, and the presence of principles governing its structure, functioning, and development.

General Concept

The concept of a system is central to systems theory and the systems approach as a whole. Many authors have analyzed this concept, developing definitions of a system with varying degrees of formalization. A definition is a linguistic model of a system, and therefore, differences in the goals and requirements for the model lead to different definitions.

In scientific literature, there are numerous definitions of a system, referring to both general systems and specific systems of various classes. Depending on the different classes of tasks in scientific, engineering, social, or economic activities, three perspectives on the definition of a system can be distinguished:

  • a system is viewed as an interconnected complex of material objects — this approach is convenient for studying natural objects or material production processes;
  • a system is viewed as consisting of two parts: on one hand, it includes a set of material objects, and on the other, information about their states. This approach is adopted in describing the management processes of material production;
  • a system is viewed in a purely informational aspect, that is, as a certain complex of relationships (connections, information). This approach is used in tasks related to socio-economic relations and management processes.

There is no single, universally accepted definition. Various authors and scientific schools offer their own approaches to the definition, often focusing on the specifics of their subject area (e.g., biology, engineering, social sciences) or on particular research tasks. The question "what is a system" largely comes down to "what we will call a system" in a specific context.

System is a term used when one wants to characterize an object being studied or designed as something whole, interconnected, and complex, about which it is impossible to immediately provide a full and exhaustive understanding, to display it, to depict it graphically, or to describe it with a mathematical expression, formula, or equation.

At different stages of representing an object as a system, in various specific situations, different definitions of a system can be used. Moreover, as the understanding of the system is refined, and as one moves to a particular level of its description or stage of research, the definition of the system not only can but should be clarified.

At the highest level of abstraction, where the properties of all systems are generalized, two mutually complementary definitions of a system can be given, corresponding to the two most important aspects of human activity—cognition of reality and its reciprocal influence:

  • a system is a reflection in the subject's consciousness of the properties of objects and their relationships in solving the task of research and cognition;[2][3]
  • a system is a way for the subject to use the properties of objects and the relationships between them in solving the task of design, operation, or management.

Key Attributes of a System

Despite the diversity of approaches (see Definitions of a system), most descriptions of a system include the following main attributes:

  • Elements (components, parts): The constituent units of a system, considered indivisible at a given level of analysis.[4]
  • Connections and relationships: Stable interactions or dependencies between elements that unite them into a single whole and limit their degrees of freedom.[5][6]
  • Structure: The way elements and connections are organized, the ordering of their interaction, which ensures the system's stability.[7]
  • Integrity: The property of a system to function as a single whole. The properties of the system as a whole are not reducible to the simple sum of the properties of its elements.[8]
  • Boundaries: A conventional or real line separating the system from its external environment. The definition of boundaries depends on the observer and the goals of the analysis.
  • Interaction with the environment: The exchange of matter, energy, or information with the surroundings through inputs and outputs.[9]
  • Goal or Function: The purpose of the system, the desired state, or the result of its behavior. The goal can be internal or set externally (e.g., by a suprasystem or an observer).

Fundamental Properties (Principles) of Systems

Systems possess general properties that manifest regardless of their nature:

  • Emergence (Synergy, Holism): The appearance of new qualities in a system that are absent in its individual elements. The capabilities of the system as a whole can exceed the sum of the capabilities of its parts.[10]
  • Hierarchy: The organization of a system into levels. Each element can be considered a subsystem (a lower-level system), and the system itself is part of a suprasystem (a higher-level system).[11]

Dynamic Aspects of a System

Systems exist and change over time:

  • State: A snapshot of the key parameter values of a system at a specific moment in time.[12]
  • Behavior: The process of a system's state changing over time under the influence of internal and external factors.[13]
  • Development: A regular, often irreversible, change in a system that leads to the emergence of new structures, functions, or qualities.
  • Lifecycle: The sequence of stages a system goes through from its conception to its decommissioning.

System Typology (Main Classes)

Systems are classified according to various criteria for ease of analysis:

By interaction with the environment:

  • Open: Actively exchange matter, energy, and information with the environment. Most real systems are open.[14]
  • Closed: Exchange only energy with the environment, but not matter.
  • Isolated: Do not exchange either matter or energy with the environment (a theoretical model).

By origin:

  • Natural: Biological, geological, cosmic, etc.
  • Artificial (man-made): Technical, organizational, social, software, etc.
  • Mixed (hybrid).

By predictability of behavior:

  • Deterministic: Behavior is fully determined by the initial state and inputs.
  • Probabilistic (stochastic): Behavior is described by probability laws.

By the nature of changes over time:

  • Static: Parameters and structure do not change over time.
  • Dynamic: The state changes over time.

By complexity:

  • Simple: A small number of elements and connections, easily described.
  • Complex: A large number of elements, diverse connections, non-linear behavior, high complexity of description and management.[15]

More detailed classifications are presented in the article Classifications of systems.

Study and Modeling of Systems

The study of systems is the focus of systems theory, the systems approach, systems analysis, cybernetics, systems engineering, and other scientific and engineering disciplines. The primary tool for study is modeling — the construction of models that provide a simplified representation of a system for the purposes of analysis, prediction, or design, for example:

  • Black box (functional model): the system is viewed as a transformer of input signals into output signals.
  • Mathematical (abstract) model: the system is defined as a set of elements and relations (a graph or algebraic model). For example, "a mathematical abstraction, a model of a dynamic phenomenon."
  • Structural model: the system as a network of elements and connections (see the definitions of Hall and Ursul).

Variety of Definitions

The description and boundaries of any system depend on the observer (researcher, designer, user) and the goals of the consideration (see Objective and subjective in systems analysis). This leads to the existence of many different definitions of a system, which emphasize its various aspects. The evolution of ideas about what a system is is examined in the article Concept of a system.

Examples of definitions:

  • A complex of interacting components. (L. von Bertalanffy)
  • A set of elements in specific relationships with each other and with the environment. (L. von Bertalanffy)
  • A whole composed of many parts. An ensemble of features. (C. Cherry)
  • A set of interconnected elements, distinct from its environment and interacting with it as a whole. (F. I. Peregudov, F. P. Tarasenko)
  • An arrangement, a set, or a collection of things connected or related in such a manner as to form a unity or whole; an arrangement of physical components connected or related in such a manner as to form or act as an entire unit. (DiStefano)
  • A combination of interacting elements organized to achieve one or more stated purposes. (ISO/IEC 15288:2008)
  • A finite set of functional elements and the relationships between them, distinguished from the environment in accordance with a specific goal within a specific time interval. (V. N. Sagatovsky)
  • A reflection in the consciousness of a subject (researcher, observer) of the properties of objects and their relationships in solving the task of research and cognition. (Yu. I. Chernyak)
  • A system S on an object A with respect to an integrative property (quality) is a collection of such elements, in such relationships, that generate the given integrative property. (E. B. Agoshkova, B. V. Akhlibininsky)
  • A collection of integrated and regularly interacting or interdependent elements, created to achieve specific goals, where the relationships between the elements are defined and stable, and the overall performance or functionality of the system is better than that of a simple sum of the elements. (PMBOK)

See also

Literature

  • Bertalanffy L. von. General Theory of Systems. - M.: Progress, 1969.
  • Sadovsky V.N. Foundations of General Systems Theory. - M.: Nauka, 1974.
  • Blauberg I.V., Sadovsky V.N., Yudin E.G. Systems Approach and Systems Analysis. - M.: Nauka, 1977.
  • Peregudov F.I., Tarasenko F.P. Introduction to Systems Analysis. - M.: Vysshaya Shkola, 1989.
  • System // New Philosophical Encyclopedia: in 4 vols. / Institute of Philosophy, Russian Academy of Sciences. - M.: Mysl, 2001.
  • Volkova V.N. Kozlov V.N. — Systems Analysis and Decision Making. Dictionary-Reference. M: Vysshaya Shkola, 2004
  • Volkova V. N., Denisov A. A. — Theory of Systems and System Analysis: A textbook for universities. M: Yurayt Publishing, 2025
  • Volkova V.N. — Origins and Prospects for the Development of Systems Sciences. St. Petersburg: Polytech-Press, 2022
  • Systems Research. Yearbook. M. Nauka Publishing, 1969-88

References

  1. ↑ "A complex of elements in interaction." — L. von Bertalanffy, Systems Research. Yearbook 1969. P. 17.
  2. ↑ "a system is a reflection in the subject's consciousness of the properties of objects and their relationships in solving the task of research, cognition;" — Yu. I. Chernyak, article "System Analysis in Economic Management".
  3. ↑ "A system is the result of the researcher's choice, related to their goal and methodology." — V.N. Volkova, A.A. Denisov, Theory of Systems and System Analysis. P. 20.
  4. ↑ "An element is the limit of the system's decomposition from the point of view of the aspect under consideration, the solution of a specific problem, and the set goal." — V.N. Volkova, A.A. Denisov, Theory of Systems and System Analysis. P. 25.
  5. ↑ "A connection is a constraint on the degrees of freedom of the elements." — V.N. Volkova, A.A. Denisov, Theory of Systems and System Analysis. P. 25.
  6. ↑ "An essential aspect of characterizing any system is the identification of... system-forming connections and relationships." — V. N. Sadovsky, Foundations of General Systems Theory. P. 83.
  7. ↑ "...the structure of a system is the set of relationships between its parts." — A. Rapoport, Systems Research. Yearbook 1969. P. 64.
  8. ↑ "In this context, a system, in a first approximation, is understood as a set of interconnected elements that acts as a certain integrity." — V. N. Sadovsky, Foundations of General Systems Theory. P. 16.
  9. ↑ "A system as a relatively distinct integrity stands in opposition to its environment, its surroundings." — V. N. Sadovsky, Foundations of General Systems Theory. P. 83.
  10. ↑ "Integrity (emergence) manifests in a system through the appearance... of new properties that are absent in its elements." — V.N. Volkova, A.A. Denisov, Theory of Systems and System Analysis. P. 59.
  11. ↑ "A consequence of a system's hierarchical structure is the possibility of sequentially including lower-level systems into higher-level systems." — V. N. Sadovsky, Foundations of General Systems Theory. P. 84.
  12. ↑ "At any given moment, a system is in a certain state..." — V. N. Sadovsky, Foundations of General Systems Theory. P. 84.
  13. ↑ "...a sequential set of system states constitutes its behavior." — V. N. Sadovsky, Foundations of General Systems Theory. P. 84.
  14. ↑ "A closed system is a system isolated from its environment... In contrast, an open system has 'inputs' and 'outputs'...'" — A. Rapoport, Systems Research. Yearbook 1969. P. 61.
  15. ↑ "...we classify the human brain, communities of organisms, the most complex industrial associations, the social structure of society, etc., as super-complex systems." — V. N. Sadovsky, Foundations of General Systems Theory. P. 3.
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