System (from Latin systēma, in turn from Greek systēma) is a set of interacting or interdependent entities, real or abstract, forming an integrated whole.

The concept of an "integrated whole" can also be stated in terms of a system embodying a set of relationships which are differentiated from relationships of the set to other elements, and from relationships between an element of the set and elements not a part of the relational regime.

Overview

The scientific research field which is engaged in the transdisciplinary study of universal system-based properties of the world is general systems theory, systems science and recently systemics. They investigate the abstract properties of the matter and mind, their organization, searching concepts and principles which are independent of the specific domain, independent of their substance, type, or spatial or temporal scales of existence.

The term system has multiple meanings :

1. A collection of organized things; as, a solar system.
2. A way of organizing or planning.
3. A whole composed of relationships among the members.

Most systems share the same common characteristics. These common characteristics include the following:

1. Systems have a structure that is defined by its parts and processes.
2. Systems are generalizations of reality.
3. Systems tend to function in the same way. This involves the inputs and outputs of material (energy and/or matter) that is then processed causing it to change in some way.
4. The various parts of a system have functional as well as structural relationships between each other.

The characteristics of systems have been studied in general systems theory.

History

The term System has a long history which can be traced back to the Greek language.

In the 19th century the first to develop the concept of a "system" in the natural sciences was the French physicist Sadi Carnot who studied thermodynamics. In 1824 he studied what he called the working substance (system), i.e. typically a body of water vapor, in steam engines, in regards to the system's ability to do work when heat is applied to it. The working substance could be put in contact with either a heat reservoir (a boiler), a cold reservoir (a stream of cold water), or a piston (to which the working body could do work by pushing on it). In 1850, the German physicist Rudolf Clausius generalized this picture to include the concept of the surroundings and began to use the term "working body" when referring to the system.

In the 1980s the term complex adaptive system was coined at the interdisciplinary Santa Fe Institute by John H. Holland, Murray Gell-Mann and others.

System concepts

Environment and boundaries

Systems theory views the world as a complex system of interconnected parts. We scope a system by defining its boundary; this means choosing which entities are inside the system and which are outside - part of the environment. We then make simplified representations (models) of the system in order to understand it and to predict or impact its future behavior. These models may define the structure and/or the behaviour of the system.