System

A system (ancient Greek sýstēma "whole composed of several individual parts") is generally defined as a definable, natural or artificial "entity" consisting of various components with different properties, which (can) be regarded as a common whole due to certain ordered relationships among them.

There is no uniform definition of the term, as the assignment of meaning varies greatly depending on the field. Accordingly, the preceding sentence is also an abstraction in the sense of a highest common denominator. The following concretizations of the individual parameters are possible:

• The spatial and/or temporal boundary of a system can be physically described by its physicality or certain forces (real / material / concrete systems) - or be of a purely mentally constructed, purposive nature (ideal / immaterial / theoretical systems).

• All natural systems are real systems, which have developed without deliberate anthropogenic influence and which maintain themselves (autopoietically) (examples: Quantum system, atom, molecule, living system, cell, organ system, psyche, ecosystem, planetary system).
• Artificial systems are systems that have been conceived and constructed by humans. They can be material or immaterial in nature; however, they often combine both. A distinction is made between (real) technical systems (examples: tool, machine, computer), social systems (examples: Social group, family, ethnicity, association, religious community, company) and socio-technical systems (examples: information system, Internet).
• Biotechnical systems (examples: livestock farming, sewage treatment plant, artificial heart) and socioecological systems (examples: cultural landscape, post-mining landscape, nature reserve) represent a mixture of natural and artificial real systems.
• Material systems are divided into open, closed and closed systems depending on the type of exchange with their environment. The system theory examines the structures and processes of fundamentally different material systems.
• Immaterial systems are exclusively artificially created, mental systems, which develop no own dynamics without "impulse" by humans and whose existence depends on material systems (examples: Conceptual system, coordinate system, axiom system, statute, model, theory).
• The components (elements, parts) of a system are determined by the fact that they fulfill from each other delimitable, different functions or tasks in the system. Basically, any real (planet, tree, organ, component, etc.) or imaginary object (sounds, gestures, signs, symbols, etc.) can be part of a system. A system can contain subsystems and itself be part of a more comprehensive system (supersystem). The nature of the components and their order determines the spatial appearance of the system.
• The (real or constructed) order within systems is based on regularities, which result in certain patterns in the interaction of the behavioral possibilities, which in principle lead to predictable effects (provided that all parameters are known). These structural rules determine the degree of complexity of the system.
• The relationships between the components is informational, material and/or energetic in nature and acts as interaction, influence and/or linkage. The degree and/or establishment or extension of relationships is called interconnectedness. Cybernetics studies the relationships and mechanisms between system components.

Specific uses of terms are proposed, discussed and applied in different disciplines.

If there are no relations between the parts of a whole, it is not a system, but mere quantities, heaps or mixtures of substances; even if the constructed arrangement of the parts is subject to a certain systematics and is called a "system" (examples: biological systematics, periodic table of the elements).

Concept of system theory

Systems theory refers to research directions of various disciplines that describe complex interrelationships by means of general theories on the functioning of systems in general. Around 1950, Ludwig von Bertalanffy (1901-1972) was the first to define systems as interaction contexts that are distinct from their environment, which in turn consists of other interaction contexts. According to basic ideas widespread in this context, systems can be understood as self-organizing functional units that produce their own continued functioning (cf. autopoiesis) and differentiate themselves from their environment in specific ways, for example by developing specific modes of differentiation. An example: Sailors put certain animals on an island in order to be able to hunt them there later. Thereby the system of animals and plants existing on the island until then gets "mixed up"; a new system develops. Sometimes endemics (= plants or animals that only occur in a certain, spatially clearly delimited environment) arise. In disciplines dealing with living organisms, systemic psychology and biology as well as sociology, living systems are distinguished from systems of a different nature.

System concept of structural linguistics

Structural linguistics (see structuralism) is based on the view that the meaning of individual linguistic elements is not determined by themselves, but by their relations to other elements - whereby their wholeness is described as a system with, among other things, this general property.

Engineering

For I&C, IEC 60050-351 defines a system as a "set of interrelated elements that are viewed as a whole in a particular context and are considered distinct from their environment."

In Functional Safety and SOTIF, a system is defined as a combination of sensor or signal input, logic (especially with microprocessor control), and actuators or signal outputs.