---
title: "Concept of a system"
source: "https://systems-analysis.info/eng/Concept_of_a_system"
wiki: "systems-analysis.info/eng"
article: "Concept_of_a_system"
language: "en"
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  - "Category:Basic concepts"
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  - "Category:Science"
  - "Category:System"
  - "Category:Systems analysis"
  - "Category:Systems approach"
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---

# Concept of a system

**The concept of a system** is a [fundamental category](https://systems-analysis.info/eng/System "System") of the [systems approach](https://systems-analysis.info/eng/Systems_approach "Systems approach"), the meaning of which has evolved with the development of science and the increasing complexity of ideas about the [structure and functioning of complex objects](https://systems-analysis.info/eng/System_complexity "System complexity"). Examining this evolution helps to understand the various aspects included in modern [definitions of a system](https://systems-analysis.info/eng/Definitions_of_a_system "Definitions of a system").

Historically, the understanding of what a [system](https://systems-analysis.info/eng/System "System") is has gone through several stages of increasing complexity.

## Early Views: Elements, Relations, Structure

Initially, a [system](https://systems-analysis.info/eng/System "System") was viewed primarily through its composition and internal organization. <a href="https://en.wikipedia.org/wiki/Ludwig_von_Bertalanffy" class="external text" rel="nofollow">L. von Bertalanffy</a> defined a system as a "complex of interacting components" or "a set of elements in certain relations with each other."<sup>[\[1\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-1)[\[2\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-2)</sup>

The main components of this view were:

- **[Elements](https://systems-analysis.info/eng/System_element "System element")** (parts, components): A certain set of constituents (\`A\`).
- **Relations** (connections, relationships): The presence of interactions or dependencies between elements (\`R\`).
- **[Structure](https://systems-analysis.info/eng/System_structure "System structure")**: The arrangement of elements and relations.

Formally, this could be represented as a pair:

*S = (A, R)*

Sometimes, a representation using intersection was used, emphasizing that a system includes only those elements and relations that form a whole:

*S = A ∩ R*

*Note: The terms "elements" — "components" and "relations" — "relationships" are often used synonymously, although "component" can also denote a collection of elements.*

## Functional Approach: Inputs, Outputs, Transformation

Later, especially with the development of cybernetics, the focus shifted to the [functioning](https://systems-analysis.info/eng/System_behavior "System behavior") of the system as a transformer:<sup>[\[3\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-3)[\[4\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-4)</sup>

\- of inputs (\`X\`) into outputs (\`Y\`) according to some rule or relation (\`R\`).

This representation (M. Mesarovic):

*S = (X, Y, R)*

allows for the use of the ["black box" model](https://systems-analysis.info/eng/Black_box "Black box"), analyzing the system by its external manifestations without delving into its internal structure.

## Accounting for Component Properties

For more accurate modeling, it became necessary to consider the properties (attributes) of the elements themselves (\`Q<sup>A</sup>\`) and their relations (\`Q<sup>R</sup>\`). A. Hall's definition included the attributes of elements:

*S = (A, R, Q<sup>A</sup>)*

<a href="https://en.wikipedia.org/wiki/Avenir_Uemov" class="external text" rel="nofollow">A. I. Uemov</a> proposed dual definitions, focusing either on the properties of elements or on the properties of relations:

*S = (A, R, Q<sup>A</sup>)* *or* *S = (A, R, Q<sup>R</sup>)*

## Inclusion of a Goal

To describe [managed](https://systems-analysis.info/eng/Management "Management"), artificial, and many biological systems, it became crucial to include a [goal](https://systems-analysis.info/eng/Goal "Goal") (\`Z\`), which reflects the system's direction or the desired result of its functioning:<sup>[\[5\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-5)[\[6\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-6)[\[7\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-7)</sup>

*S = (A, R, Z)*

In [systems analysis](https://systems-analysis.info/eng/Systems_analysis "Systems analysis"), working with goals is a central stage (see Goal in systems analysis).

## Interaction with the Environment and Dynamics: Open Systems

Most real-world systems interact with their surroundings. <a href="https://en.wikipedia.org/wiki/Ludwig_von_Bertalanffy" class="external text" rel="nofollow">L. von Bertalanffy</a> introduced the concept of an open system, which exchanges matter, energy, or information with its [environment](https://systems-analysis.info/eng/System_environment "System environment") (\`E\`).<sup>[\[8\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-8)</sup>

Accounting for [dynamics](https://systems-analysis.info/eng/Dynamic_properties "Dynamic properties") also required the introduction of a time interval (\`T\`). The definition by V. N. Sagatovsky considers these aspects:

*S = (A, R, Z, E, T)*

where *A* – functional elements, *R* – relations, *Z* – goal, *E* – environment, *T* – time interval.

## The Role of the Observer: The Subjective Aspect

Starting with the works of W. R. Ashby and especially Yu. I. Chernyak, the modern [systems approach](https://systems-analysis.info/eng/Systems_approach "Systems approach") explicitly includes an [observer](https://systems-analysis.info/eng/Observer_in_the_systems_approach "Observer in the systems approach") (\`N\`) in its consideration. The description of a system, its boundaries, significant [elements](https://systems-analysis.info/eng/System_element "System element") and relations, as well as the analysis [goals](https://systems-analysis.info/eng/Goal "Goal"), depend on the subject. Chernyak's definition: "A system is a reflection in the subject's consciousness... of the properties of objects and their relations...":<sup>[\[9\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-9)</sup>

*S = (A, R, Z, N)*

Later, Chernyak also added the observer's language (\`L<sub>N</sub>\`):

*S = (A, R, Z, N, L<sub>N</sub>)*

The inclusion of the observer emphasizes the dialectic of the [objective and subjective](https://systems-analysis.info/eng/Objective_and_subjective_in_systems_analysis "Objective and subjective in systems analysis") in systems research and the importance of [levels (strata)](https://systems-analysis.info/eng/Levels_of_system_representation "Levels of system representation") of system consideration.

## The Concept's Evolution and Scientific Development

The increasing complexity of the concept of a system occurred in parallel with the development of cybernetics, [general systems theory](https://systems-analysis.info/eng/Systems_theory "Systems theory"), [systems analysis](https://systems-analysis.info/eng/Systems_analysis "Systems analysis"), [operations research](https://systems-analysis.info/eng/Operations_research "Operations research"), and [systems engineering](https://systems-analysis.info/eng/Systems_engineering "Systems engineering"). Each of these fields contributed to the understanding of the structure, behavior, management, and [development](https://systems-analysis.info/eng/System_development "System development") of systems (see Development of the systems approach).<sup>[\[10\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-10)</sup>

## Choosing a Definition

The multitude of definitions reflects the complexity of the phenomenon of a system itself. When conducting [systems analysis](https://systems-analysis.info/eng/Systems_analysis "Systems analysis"), it is necessary to select or formulate a "working" [definition](https://systems-analysis.info/eng/Definitions_of_a_system "Definitions of a system") that is adequate for the [goals](https://systems-analysis.info/eng/Goal "Goal") of the research and the [level](https://systems-analysis.info/eng/Levels_of_system_representation "Levels of system representation") of consideration. This definition can be refined during the course of the analysis.<sup>[\[11\]](https://systems-analysis.info/eng/Concept_of_a_system#cite_note-11)</sup>

## External links

- <a href="https://en.wikipedia.org/wiki/System" class="external text" rel="nofollow">System — Wikipedia</a>

## See also

- [System](https://systems-analysis.info/eng/System "System")
- [Definitions of a system](https://systems-analysis.info/eng/Definitions_of_a_system "Definitions of a system")
- [Systems approach](https://systems-analysis.info/eng/Systems_approach "Systems approach")
- [Systems analysis](https://systems-analysis.info/eng/Systems_analysis "Systems analysis")
- [Systems theory](https://systems-analysis.info/eng/Systems_theory "Systems theory")
- [History of the systems approach](https://systems-analysis.info/eng/History_of_the_systems_approach "History of the systems approach")
- [System structure](https://systems-analysis.info/eng/System_structure "System structure")
- [System element](https://systems-analysis.info/eng/System_element "System element")
- [Connections in systems](https://systems-analysis.info/eng/Connections_in_systems "Connections in systems")
- [System environment](https://systems-analysis.info/eng/System_environment "System environment")
- [System boundary](https://systems-analysis.info/eng/System_boundary "System boundary")
- [Goal (systems analysis)](https://systems-analysis.info/eng/Goal_(systems_analysis) "Goal (systems analysis)")
- [Observer in the systems approach](https://systems-analysis.info/eng/Observer_in_the_systems_approach "Observer in the systems approach")
- [Objective and subjective in systems analysis](https://systems-analysis.info/eng/Objective_and_subjective_in_systems_analysis "Objective and subjective in systems analysis")
- [Open system](https://systems-analysis.info/eng/Open_system_(systems_theory) "Open system (systems theory)")
- [Levels of system representation](https://systems-analysis.info/eng/Levels_of_system_representation "Levels of system representation")

## Literature

- Volkova V.N., Kozlov V.N. — Systems Analysis and Decision Making. Dictionary-Reference. Moscow: Vysshaya Shkola, 2004
- Volkova V.N., Denisov A.A. — Theory of Systems and Systems Analysis: a textbook for universities. Moscow: Yurayt Publishing, 2025
- Volkova V.N. — Origins and Prospects for the Development of Systems Sciences. St. Petersburg: Polytech-Press, 2022
- Systems Research. Yearbook. Moscow: Nauka Publishing, 1969-88
- Bertalanffy, L. von. General System Theory. - Moscow: Progress, 1969.
- Sadovsky, V.N. Foundations of the General Theory of Systems. - Moscow: Nauka, 1974.
- Blauberg I.V., Sadovsky V.N., Yudin E.G. The Systems Approach and Systems Analysis. - Moscow: Nauka, 1977.
- Peregudov F.I., Tarasenko F.P. Introduction to Systems Analysis. - Moscow: Vysshaya Shkola, 1989.
- System // New Philosophical Encyclopedia: in 4 vols. / Institute of Philosophy, Russian Academy of Sciences. - Moscow: Mysl, 2001.
- System // Wikipedia. URL: https://en.wikipedia.org/wiki/System (accessed: 2025-04-28).

## References

1.  <span id="cite_note-1">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-1) "A complex of elements in interaction." — L. von Bertalanffy, *Systems Research. Yearbook 1969. P. 17*.</span>
2.  <span id="cite_note-2">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-2) "A set of elements with relations between them and between their attributes." — R. Fagen, A. Hall, *Systems Research. Yearbook 1969. P. 17*.</span>
3.  <span id="cite_note-3">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-3) "A system is defined as a certain relation defined on the Cartesian product of a certain family of sets." — M. Mesarovic (cited by A. I. Uemov), *Systems Research. Yearbook 1969. P. 82*.</span>
4.  <span id="cite_note-4">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-4) "Systems are studied by their functional behavior: they are subjected to certain influences (data at the 'input' of systems) and their responses are recorded (data at the 'output'); the results obtained are 'encoded in the language of the system's properties'." — Yu. V. Sachkov, *Systems Research. Yearbook 1969. P. 129*.</span>
5.  <span id="cite_note-5">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-5) "A system... accepts certain inputs and... produces outputs that ensure the achievement of a goal – maximizing some function of the inputs and outputs" — Richard Kershner (cited in S. Young), *System Management of an Organization. P. 16*.</span>
6.  <span id="cite_note-6">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-6) "Systems analysis is a methodology for research... by representing these objects as goal-oriented systems..." — Yu.I. Chernyak, article "Systems Analysis in Economic Management".</span>
7.  <span id="cite_note-7">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-7) "Then, the concept of a goal appears in the definitions of a system." — V.N. Volkova, A.A. Denisov, *Theory of Systems and Systems Analysis. P. 18*.</span>
8.  <span id="cite_note-8">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-8) "The study of an object as a system is methodologically inseparable from the analysis of its conditions of existence and the analysis of the system's environment." — V. N. Sadovsky,</span>
9.  <span id="cite_note-9">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-9) "A system is the result of a researcher's choice, related to their goal and methodology." — V.N. Volkova, A.A. Denisov, *Theory of Systems and Systems Analysis. P. 20*.</span>
10. <span id="cite_note-10">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-10) "...the concept of 'system' became widely used in various fields of knowledge, attracted the interest of engineers, and at a certain stage of scientific development, systems theory emerged as an independent science." — V.N. Volkova, A.A. Denisov, *Systems Theory. P. 5*.</span>
11. <span id="cite_note-11">[↑](https://systems-analysis.info/eng/Concept_of_a_system#cite_ref-11) "The choice of a system's definition reflects the adopted concept and is, in fact, the beginning of modeling." — V.N. Volkova, A.A. Denisov, *Theory of Systems and Systems Analysis. P. 22*.</span>