Concept of a system

The concept of a system is a fundamental category of the 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. Examining this evolution helps to understand the various aspects included in modern definitions of a system.

Historically, the understanding of what a system is has gone through several stages of increasing complexity.

Early Views: Elements, Relations, Structure

Initially, a system was viewed primarily through its composition and internal organization. L. von Bertalanffy defined a system as a "complex of interacting components" or "a set of elements in certain relations with each other."

The main components of this view were:

• Elements (parts, components): A certain set of constituents (`A`).
• Relations (connections, relationships): The presence of interactions or dependencies between elements (`R`).
• 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 of the system as a transformer:

- 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, 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^A)

A. I. Uemov proposed dual definitions, focusing either on the properties of elements or on the properties of relations:

S = (A, R, Q^A) or S = (A, R, Q^R)

Inclusion of a Goal

To describe managed, artificial, and many biological systems, it became crucial to include a goal (`Z`), which reflects the system's direction or the desired result of its functioning:

S = (A, R, Z)

In 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. L. von Bertalanffy introduced the concept of an open system, which exchanges matter, energy, or information with its environment (`E`).

Accounting for dynamics 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 explicitly includes an observer (`N`) in its consideration. The description of a system, its boundaries, significant elements and relations, as well as the analysis goals, 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...":

S = (A, R, Z, N)

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

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

The inclusion of the observer emphasizes the dialectic of the objective and subjective in systems research and the importance of levels (strata) 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, systems analysis, operations research, and systems engineering. Each of these fields contributed to the understanding of the structure, behavior, management, and development of systems (see Development of the systems approach).

Choosing a Definition

The multitude of definitions reflects the complexity of the phenomenon of a system itself. When conducting systems analysis, it is necessary to select or formulate a "working" definition that is adequate for the goals of the research and the level of consideration. This definition can be refined during the course of the analysis.

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).

See also

• System
• Definitions of a system
• Systems approach
• Systems analysis
• Systems theory
• Development of the systems approach
• System structure
• System element
• Relations in systems
• System environment
• System boundaries
• Goal in systems analysis
• Observer in the systems approach
• Objective and subjective in systems analysis
• Open system
• Levels of system representation