Open system

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A system that is open with regard to any category is a system that has an exchange balance at the interfaces to its environment, which in this category cannot be equal to zero.


In physics , open, closed, and self-contained (or isolated) systems are used.

A system is defined as open that can exchange both energy and matter (or particles ) with its environment. An example of an open system is an open cooking pot that exchanges both energy in the form of heat and matter in the form of water vapor with its surroundings.

The exact calculation of open systems is therefore not possible, but can only be approximated using models . In many cases, however, a stationary process can occur, for example in a steady state .

Information technology

In information technology , an "open system" is a system environment that ensures interoperability , portability and expandability through open interfaces and specifications .


Living systems are open because living beings import negentropy to maintain them and have to be in constant exchange of substances and energy with their environment. However, the openness is more or less limited in terms of quantity and quality.

From the point of view of information theory, living systems increase their redundancy by exporting entropy (or by importing negative entropy) , which according to ISO / IEC DIS 2382-16 (information theory) can be described as the distance between the current entropy of a system and its maximum entropy .


Social systems in the sense of Niklas Luhmann's sociological systems theory are open. As in general for open systems, it also applies to social systems that openness does not necessarily lead to a reduction in entropy in these systems, but openness is only one of the prerequisites for the possibility of lowering entropy in the system. Since the transfer of the term autopoiesis to his theory in the early 1980s (also viewed as Luhmann's “autopoietic turn”), Luhmann has no longer defined social systems as “open” (i.e. in direct exchange with the environment), but rather as "autopoietic closed" or "operationally closed". According to Luhmann, the perception of the environment through a system is therefore always selective. A system cannot change its specific way of perceiving the environment without losing its specific identity.

As in the case of biological systems, the export of entropy means here that the redundancy in the social system is increased, i.e. the structure of elements that are not necessarily, but only possibly needed. Social and biological systems require redundancy at least as much as they experience contingency . For humans, contingency is the openness and uncertainty of human life experiences.

See also


  1. George Coulouris, Jean Dollimore, Tim Kindberg: Distributed systems: concepts and design . Addison-Wesley, Harlow, England 2005., ISBN 0321263545 .
  2. ^ Andrew S Tanenbaum: Distributed Systems - Principles and Paradigms . Pearson Education Germany, ISBN 978-3-8273-7293-2 .
  3. Erwin Schrödinger coined the term “ negentropy ” , which stands for negative entropy, in What is life? - Looking at the living cell through the physicist's eyes (1951).
  4. see assumptions by Niklas Luhmann in Introduction to Systems Theory (Lecture Transcript 1991/92, edited by Dirk Baecker ), 2004, pp. 44 to 45 and 93, ISBN 3-89670-459-1 .