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{{Short description|Interdisciplinary study of systems}} 
{{Citation style|date=July 2025}}
{{Complex systems}}
'''Systems theory''' is the [[Transdisciplinarity|transdisciplinary]]<ref>{{cite book |doi=10.1016/B978-0-12-375038-9.00212-0 |chapter=Systems Approach |title=Encyclopedia of Creativity |date=2011 |last1=Montuori |first1=A. |pages=414–421 |isbn=978-0-12-375038-9 }}</ref> study of [[system]]s, i.e. cohesive groups of interrelated, interdependent components that can be [[natural]] or [[artificial]]. Every system has causal boundaries, is influenced by its context, defined by its structure, function and role, and expressed through its relations with other systems. A system is "more than the sum of its parts" when it expresses [[synergy]] or [[emergent behavior]].<ref>{{cite journal |last1=Von Bertalanffy |first1=Ludwig |title=The History and Status of General Systems Theory |journal=The Academy of Management Journal |date=1972 |volume=15 |issue=4 |pages=407–426 |jstor=255139 }}</ref>

Changing one component of a system may affect other components or the whole system. It may be possible to predict these changes in patterns of behavior. For systems that learn and adapt, the growth and the degree of [[adaptation]] depend upon how well the system is engaged with its environment and other contexts influencing its organization. Some systems support other systems, maintaining the other system to prevent failure. The goals of systems theory are to model a system's dynamics, [[Theory of constraints|constraints]], conditions, and relations; and to elucidate principles (such as purpose, measure, methods, tools) that can be discerned and applied to other systems at every level of nesting, and in a wide range of fields for achieving optimized [[equifinality]].<ref>{{cite journal |last1=Beven |first1=Keith |title=A manifesto for the equifinality thesis |journal=Journal of Hydrology |date=March 2006 |volume=320 |issue=1–2 |pages=18–36 |doi=10.1016/j.jhydrol.2005.07.007 |bibcode=2006JHyd..320...18B |url=https://eprints.lancs.ac.uk/id/eprint/4419/1/Manifesto12.pdf }}</ref>

General systems theory is about developing broadly applicable concepts and principles, as opposed to concepts and principles specific to one domain of knowledge. It distinguishes dynamic or active systems from static or passive systems. Active systems are activity structures or components that interact in behaviours and processes or interrelate through formal contextual boundary conditions (attractors). Passive systems are structures and components that are being processed. For example, a computer program is passive when it is a file stored on the hard drive and active when it runs in memory.<ref>{{cite book|author=Paolo Rocchi|title=Technology + Culture|url=https://books.google.com/books?id=2X17MLCjsKgC&pg=PA8|year=2000|publisher=IOS Press|isbn=978-1-58603-035-3}}</ref> The field is related to [[systems thinking]], machine logic, and [[systems engineering]].

==Overview==
{{essay|date=November 2020}}
Systems theory is manifest in the work of practitioners in many disciplines, for example the works of physician [[Alexander Bogdanov]], biologist [[Ludwig von Bertalanffy]], linguist [[Béla H. Bánáthy]], and sociologist [[Talcott Parsons]]; in the study of ecological systems by [[Howard T. Odum]], [[Eugene Odum]]; in [[Fritjof Capra]]'s study of [[organizational theory]]; in the study of [[management]] by [[Peter Senge]]; in interdisciplinary areas such as [[Human Resource Development|human resource development]] in the works of [[Richard A. Swanson]]; and in the works of educators [[Debora Hammond]] and Alfonso Montuori.

As a [[Transdisciplinarity|transdisciplinary]], interdisciplinary, and [[Multiperspectivalism|multiperspectival]] endeavor, systems theory brings together principles and concepts from [[ontology]], the [[philosophy of science]], [[physics]], [[computer science]], [[biology]], and [[engineering]], as well as [[geography]], [[sociology]], [[political science]], [[psychotherapy]] (especially [[family systems therapy]]), and [[economics]].

Systems theory promotes dialogue between autonomous areas of study as well as within [[systems science]] itself. In this respect, with the possibility of misinterpretations, von Bertalanffy<ref>Bertalanffy, (1950: 142).</ref> believed a general theory of systems "should be an important regulative device in science," to guard against superficial analogies that "are useless in science and harmful in their practical consequences."

Others remain closer to the direct systems concepts developed by the original systems theorists. For example, [[Ilya Prigogine]], of [[the Center for Complex Quantum Systems]] at the [[University of Texas]], has studied [[emergence|emergent properties]], suggesting that they offer [[analogy|analogues]] for [[life|living systems]]. The [[Distinction (philosophy)|distinction]] of [[autopoiesis]] as made by [[Humberto Maturana]] and [[Francisco Varela]] represent further developments in this field. Important names in contemporary systems science include [[Russell Ackoff]], [[Ruzena Bajcsy]], [[Béla H. Bánáthy]], [[Gregory Bateson]], [[Anthony Stafford Beer]], [[Peter Checkland]], [[Barbara Grosz]], [[Brian Wilson (systems scientist)|Brian Wilson]], [[Robert L. Flood]], [[Allenna Leonard]], [[Radhika Nagpal]], [[Fritjof Capra]], [[Warren McCulloch]], [[Kathleen Carley]], [[Michael C. Jackson]], [[Katia Sycara]], and [[Edgar Morin]] among others.

With the modern foundations for a general theory of systems following World War I, [[Ervin László]], in the preface for Bertalanffy's book, ''Perspectives on General System Theory'', points out that the [[translation]] of "general system theory" from German into English has "wrought a certain amount of havoc":<ref name=":1" />

{{blockquote|It (General System Theory) was criticized as pseudoscience and said to be nothing more than an admonishment to attend to things in a holistic way. Such criticisms would have lost their point had it been recognized that von Bertalanffy's general system theory is a perspective or paradigm, and that such basic conceptual frameworks play a key role in the development of exact scientific theory. .. Allgemeine Systemtheorie is not directly consistent with an interpretation often put on 'general system theory,' to wit, that it is a (scientific) "theory of general systems." To criticize it as such is to shoot at straw men. Von Bertalanffy opened up something much broader and of much greater significance than a single theory (which, as we now know, can always be falsified and has usually an ephemeral existence): he created a new paradigm for the development of theories.}}

Theorie (or ''Lehre'') "has a much broader meaning in German than the closest English words 'theory' and 'science'," just as ''[[Wissenschaft]]'' (or 'Science').<ref name=":1" /> These ideas refer to an organized body of knowledge and "any systematically presented set of concepts, whether [[empirically]], [[axiomatically]], or [[philosophical]]ly" represented, while many associate ''Lehre'' with theory and science in the etymology of general systems, though it also does not translate from the German very well; its "closest equivalent" translates to 'teaching', but "sounds dogmatic and off the mark."<ref name=":1" /> An adequate overlap in meaning is found within the word "[[nomothetic]]", which can mean "having the capability to posit long-lasting sense." While the idea of a "general systems theory" might have lost many of its root meanings in the translation, by defining a new way of thinking about science and [[Paradigm|scientific paradigms]], systems theory became a widespread term used for instance to describe the interdependence of relationships created in [[organization]]s.

A system in this frame of reference can contain regularly interacting or interrelating groups of activities. For example, in noting the influence in the evolution of "an individually oriented [[industrial psychology]] [into] a systems and developmentally oriented [[Industrial and organizational psychology|organizational psychology]]," some theorists recognize that organizations have complex social systems; separating the parts from the whole reduces the overall effectiveness of organizations.<ref name="Schein">{{cite book |last=Schein |first=E. H. |title=Organizational Psychology |date=1980 |publisher=Prentice-Hall |location=New Jersey |pages=4–11}}</ref> This difference, from conventional models that center on individuals, structures, departments and units, separates in part from the whole, instead of recognizing the interdependence between groups of individuals, structures and processes that enable an organization to function.

László explains that the new systems view of organized complexity went "one step beyond the Newtonian view of organized simplicity" which reduced the parts from the whole, or understood the whole without relation to the parts. The relationship between organisations and their [[environment (systems)|environments]] can be seen as the foremost source of complexity and interdependence. In most cases, the whole has properties that cannot be known from analysis of the constituent elements in isolation.<ref>{{Cite book |last=Laszlo |first=Ervin |author-link=Ervin László |title=The Systems View of the World: The Natural Philosophy of the New Developments in the Sciences |date=1972 |publisher=George Braziller, Inc. (simultaneously with Doubleday Canada, Limited) |publication-place=New York, New York |pages=[https://archive.org/details/systemsviewofw00lasz/page/14/mode/2up?q=%22one+step+beyond+the+Newtonian+view+of+organized+simplicity%22 14–15] |isbn=0-8076-0637-5 |lccn=71-188357 }}</ref>

[[Béla H. Bánáthy]], who argued—along with the founders of the systems society—that "the benefit of humankind" is the purpose of science, has made significant and far-reaching contributions to the area of systems theory. For the Primer Group at the [[International Society for the Systems Sciences|International Society for the System Sciences]], Bánáthy defines a perspective that iterates this view:<ref>[[Béla H. Bánáthy]], 1997: ¶ 22.</ref>{{Full citation needed|date=October 2016}}

{{blockquote|The systems view is a world-view that is based on the discipline of SYSTEM INQUIRY. Central to systems inquiry is the concept of SYSTEM. In the most general sense, system means a configuration of parts connected and joined together by a web of relationships. The Primer Group defines system as a family of relationships among the members acting as a whole. Von Bertalanffy defined system as "elements in standing relationship."}}

==Applications==

===Art===
{{Main|Systems art}}

===Biology===
{{Main|Systems biology}}
Systems biology is a movement that draws on several trends in [[bioscience]] research. Proponents describe systems biology as a biology-based interdisciplinary study field that focuses on complex interactions in [[biological system]]s, claiming that it uses a new perspective ([[holism]] instead of [[reductionist|reduction]]).

Particularly from the year 2000 onwards, the biosciences use the term widely and in a variety of contexts. An often stated ambition of systems biology is the modelling and discovery of [[emergent property|emergent properties]] which represents properties of a system whose theoretical description requires the only possible useful techniques to fall under the remit of systems biology. It is thought that [[Ludwig von Bertalanffy]] may have created the term ''systems biology'' in 1928.<ref name="LVB1928">1928, Kritische Theorie der Formbildung, Borntraeger. In English: Modern Theories of Development: An Introduction to Theoretical Biology, Oxford University Press, New York: Harper, 1933</ref>

Subdisciplines of systems biology include:
* [[Systems neuroscience]]
* [[Systems pharmacology]]

====Ecology====
{{Main|Systems ecology}}
Systems ecology is an [[interdisciplinary]] field of [[ecology]] that takes a [[holism|holistic]] approach to the study of [[ecological systems]], especially [[ecosystem]]s;<ref>Shugart, Herman H., and Robert V. O'Neill. "Systems Ecology". Dowden, Hutchingon & Ross, 1979.</ref><ref>Van Dyne, George M. "Ecosystems, Systems Ecology, and Systems Ecologists". ORNL- 3975. Oak Ridge National Laboratory, Oak Ridge, TN, 1966.</ref><ref>{{cite book|last=Wilkinson|first=David M.|title=Fundamental Processes in Ecology: An Earth Systems Approach|year=2006|publisher=Oxford University Press|isbn=9780198568469|url=https://books.google.com/books?id=PFGWHyRyzBwC&q=Fundamental+Processes+in+Ecology:+An+Earth+Systems+Approach|access-date=2020-11-12|archive-date=2024-04-21|archive-url=https://web.archive.org/web/20240421022110/https://books.google.com/books?id=PFGWHyRyzBwC&q=Fundamental+Processes+in+Ecology:+An+Earth+Systems+Approach|url-status=live}}</ref> it can be seen as an application of general systems theory to ecology.

Central to the systems ecology approach is the idea that an ecosystem is a [[complex system]] exhibiting [[emergent properties]]. Systems ecology focuses on interactions and transactions within and between biological and ecological systems, and is especially concerned with the way the functioning of ecosystems can be influenced by human interventions. It uses and extends concepts from [[thermodynamics]] and develops other macroscopic descriptions of complex systems.

===Chemistry===
{{Main|Systems chemistry}}
Systems chemistry is the science of studying [[Network science|networks]] of interacting molecules, to create new functions from a set (or library) of molecules with different hierarchical levels and emergent properties.<ref>{{cite journal |last1=Ludlow |first1=R. Frederick |last2=Otto |first2=Sijbren |title=Systems chemistry |journal=Chemical Society Reviews |date=2008 |volume=37 |issue=1 |pages=101–108 |doi=10.1039/b611921m |pmid=18197336 }}</ref> Systems chemistry is also related to the origin of life ([[abiogenesis]]).<ref>{{cite journal |last1=von Kiedrowski |first1=Günter |last2=Otto |first2=Sijbren |last3=Herdewijn |first3=Piet |title=Welcome Home, Systems Chemists! |journal=Journal of Systems Chemistry |date=December 2010 |volume=1 |issue=1 |article-number=1 |doi=10.1186/1759-2208-1-1 |doi-access=free }}</ref>

===Engineering===
{{Main|Systems engineering}}
Systems engineering is an [[interdisciplinary]] approach and means for enabling the realisation and deployment of successful [[system]]s. It can be viewed as the application of engineering techniques to the engineering of systems, as well as the application of a systems approach to engineering efforts.<ref>{{cite book | last = Thomé | first = Bernhard | date = 1993 | title = Systems Engineering: Principles and Practice of Computer-based Systems Engineering | publisher = John Wiley & Sons | location = Chichester| isbn = 0-471-93552-2}}</ref> Systems engineering integrates other disciplines and specialty groups into a team effort, forming a structured development process that proceeds from concept to production to operation and disposal. Systems engineering considers both the business and the technical needs of all customers, with the goal of providing a quality product that meets the user's needs.<ref>{{cite web|author=INCOSE|author-link=INCOSE|url=http://www.incose.org/practice/whatissystemseng.aspx|title=What is Systems Engineering|access-date=2006-11-26|archive-date=2006-11-28|archive-url=https://web.archive.org/web/20061128033211/http://www.incose.org/practice/whatissystemseng.aspx|url-status=live}}</ref><ref>Blockley, David; Godfrey, Patrick, ''Doing it Differently: Systems for Rethinking Infrastructure (2nd Edition)'' ICE Publishing, London, England, {{ISBN|978-0-7277-6082-1}}.</ref>

====User-centered design process====
Systems thinking is a crucial part of [[user-centered design]] processes and is necessary to understand the whole impact of a new [[human computer interaction]] (HCI) [[Information System|information system]].<ref>{{cite web |last1=Söderström |first1=Jonas |title=Algoritmiska larm belastar sjukvården |url=http://javlaskitsystem.se/2020/02/algoritmiska-larm-belastar-sjukvarden/ |website=Jävla skitsystem |access-date=12 September 2020 |archive-date=6 August 2020 |archive-url=https://web.archive.org/web/20200806011103/http://javlaskitsystem.se/2020/02/algoritmiska-larm-belastar-sjukvarden/ |url-status=live }}</ref> Overlooking this and developing software without insights input from the future users (mediated by user experience designers) is a serious design flaw that can lead to complete failure of information systems, increased stress and mental illness for users of information systems leading to increased costs and a huge waste of resources.<ref>{{cite book |last1=Söderström |first1=Jonas |title=Jävla skitsystem! |date=2010 |publisher=Karnaval Förlag |location=Stockholm |page=16,17}}</ref> It is currently surprisingly uncommon for organizations and governments to investigate the project management decisions leading to serious design flaws and lack of usability.{{citation needed|date=September 2020}}

The [[Institute of Electrical and Electronics Engineers]] estimates that roughly 15% of the estimated $1 trillion used to develop information systems every year is completely wasted and the produced systems are discarded before implementation by entirely preventable mistakes.<ref>{{cite web |last1=Charette |first1=Robert N. |title=Why Software Fails |url=https://spectrum.ieee.org/why-software-fails |website=IEEE Spectrum |date=2 September 2005 |access-date=12 September 2020 |archive-date=9 September 2020 |archive-url=https://web.archive.org/web/20200909063905/https://spectrum.ieee.org/computing/software/why-software-fails |url-status=live }}</ref> According to the CHAOS report published in 2018 by the Standish Group, a vast majority of information systems fail or partly fail according to their survey:
{{Blockquote|Pure success is the combination of high customer satisfaction with high return on value to the organization. Related figures for the year 2017 are: successful: 14%, challenged: 67%, failed 19%.<ref>{{cite web |last1=Portman |first1=Henny |title=Review CHAOS Report 2018 |url=https://hennyportman.wordpress.com/2020/01/03/review-chaos-report-2018/ |website=Henny Portman's Blog |date=3 January 2020 |access-date=11 September 2020 |archive-date=29 September 2020 |archive-url=https://web.archive.org/web/20200929194449/https://hennyportman.wordpress.com/2020/01/03/review-chaos-report-2018/ |url-status=live }}</ref>}}

===Mathematics===
{{Main|System dynamics}}
System dynamics is an approach to understanding the [[nonlinearity|nonlinear]] behaviour of [[complex system]]s over time using [[Stock and flow|stocks, flows]], internal [[feedback loop]]s, and time delays.<ref name="sysdyn">{{Cite web |url=http://web.mit.edu/sysdyn/sd-intro/ |title=MIT System Dynamics in Education Project (SDEP)<!-- Bot generated title --> |access-date=2016-10-28 |archive-date=2019-02-13 |archive-url=https://web.archive.org/web/20190213102210/http://web.mit.edu/sysdyn/sd-intro/ |url-status=live }}</ref> The field of [[category theory]] has recently been used by researchers including David Jaz Myers<ref>{{Cite web |last=Myers |first=David Jaz |title=David Jaz Myers – Student of mathematics and otherwise. |url=https://www.davidjaz.com/ |access-date=2025-09-02 |website=www.davidjaz.com}}</ref> to formalise concepts from systems theory.

===Social sciences and humanities===
* [[Systems theory in anthropology]]
* [[Systems theory in archaeology]]
* [[Systems theory in political science]]

====Psychology====
{{Main|Systems psychology}}
Systems psychology is a branch of [[psychology]] that studies [[human behaviour]] and [[experience]] in [[complex system]]s.

It received inspiration from systems theory and systems thinking, as well as the basics of theoretical work from [[Roger Barker]], [[Gregory Bateson]], [[Humberto Maturana]] and others. It makes an approach in [[psychology]] in which groups and individuals receive consideration as [[systems]] in [[homeostasis]]. Systems psychology "includes the domain of [[engineering psychology]], but in addition seems more concerned with societal systems<ref>{{Cite book|title=Dynamical social psychology: Finding order in the flow of human experience|last=Vallacher, R. R., & Nowak, A.|publisher=Guilford Publications|year=2007|location=New York}}</ref> and with the study of motivational, affective, cognitive and group behavior that holds the name engineering psychology."<ref>Lester R. Bittel and Muriel Albers Bittel (1978), ''Encyclopedia of Professional Management'', McGraw-Hill, {{ISBN|0-07-005478-9}}, p. 498.</ref>

In systems psychology, characteristics of [[organizational behaviour]] (such as individual needs, rewards, [[expectation (epistemic)|expectation]]s, and attributes of the people interacting with the [[systems]]) "considers this process in order to create an effective system."<ref>Michael M. Behrmann (1984), ''Handbook of Microcomputers in Special Education''. College Hill Press. {{ISBN|0-933014-35-X}}. p. 212.</ref>

===Informatics===
System theory has been applied in the field of neuroinformatics and connectionist cognitive science. Attempts are being made in neurocognition to merge connectionist cognitive neuroarchitectures with the approach of system theory and [[dynamical systems theory]].<ref>{{cite book |doi=10.1201/9781351043526 |title=Cognitive Science |date=2021 |last1=Maurer |first1=Harald |isbn=978-1-351-04352-6 }} chap. 1.4, 2., 3.26</ref>

==History==
===Precursors===
{| class="wikitable" style="float:right; margin:10px; width:40%;"
! Timeline
|-
|
Predecessors
* [[Baron d'Holbach]] (1723/1789), [[Henri de Saint-Simon|Saint-Simon]] (1760–1825), [[Auguste Comte]] (1798–1857), [[Karl Marx]] (1818–1883), [[Friedrich Engels]] (1820–1895), [[Herbert Spencer]] (1820–1903), [[Rudolf Clausius]] (1822–1888), [[Vilfredo Pareto]] (1848–1923), [[Émile Durkheim]] (1858–1917), [[Alexander Bogdanov]] (1873–1928), [[Nicolai Hartmann]] (1882–1950), [[Robert Maynard Hutchins]] (1929–1951), among others
Founders
* 1946–1953: [[Macy conferences]]
* 1948: [[Norbert Wiener]] publishes ''[[Cybernetics: Or Control and Communication in the Animal and the Machine]]''
* 1951: [[Talcott Parsons]] publishes ''The Social System''<ref>{{cite book|last=Parsons|first=Talcott|title=The Social System|date=1951|publisher=Glencoe}}</ref>
* 1954: The [[Society for the Advancement of General Systems Theory]] is established by [[Ludwig von Bertalanffy]], [[Anatol Rapoport]], [[Ralph W. Gerard]], [[Kenneth Boulding]].
* 1955: [[William Ross Ashby]] publishes ''Introduction to Cybernetics''
* 1968: Bertalanffy publishes ''General System Theory: Foundations, Development, Applications''

Other contributors
* 1970–1990 [[Second-order cybernetics]] ([[Heinz von Foerster]], [[Gregory Bateson]], [[Humberto Maturana]], and others)
* 1971–1973 [[Cybersyn]], rudimentary internet and cybernetic system for democratic economic planning developed by [[Stafford Beer]] in Chile under the [[Allende government]]
* 1970s: [[Catastrophe theory]] ([[René Thom]], [[E.C. Zeeman]]) [[Dynamical system]]s in mathematics.
* 1977: [[Ilya Prigogine]] received the Nobel Prize for his works on [[self-organization]], conciliating important ''systems theory'' concepts with [[thermodynamic system|system thermodynamics]].
* 1980s: [[Chaos theory]] ([[David Ruelle]], [[Edward Lorenz]], [[Mitchell Feigenbaum]], [[Steve Smale]], [[James A. Yorke]])
* 1986: [[Context theory]] ([[Anthony Wilden]])
* 1988: [[List of systems science organizations|International Society for Systems Science]] is established.
* 1990: [[Complex adaptive system]]s ([[John Henry Holland|John H. Holland]], [[Murray Gell-Mann]], [[W. Brian Arthur]])
|}
Systems thinking can date back to antiquity, whether considering the first systems of written communication with Sumerian [[cuneiform]] to [[Maya numerals]], or the feats of engineering with the [[Egyptian pyramids]]. Differentiated from Western [[rationalist]] traditions of philosophy, [[C. West Churchman]] often identified with the [[I Ching]] as a systems approach sharing a frame of reference similar to [[pre-Socratic]] philosophy and [[Heraclitus]].<ref name=Hammond>{{cite book|title=The Science of Synthesis|last=Hammond, Debora|year=2003|publisher=University of Colorado Press|isbn=9780870817229}}</ref>{{rp|12–13}} [[Ludwig von Bertalanffy]] traced systems concepts to the philosophy of [[Gottfried Leibniz]] and [[Nicholas of Cusa]]'s ''[[Coincidentia oppositorum#Coincidentia oppositorum|coincidentia oppositorum]]''. While modern systems can seem considerably more complicated, they may embed themselves in history.

Figures like [[James Prescott Joule|James Joule]] and [[Nicolas Léonard Sadi Carnot|Sadi Carnot]] represent an important step to introduce the ''systems approach'' into the (rationalist) hard sciences of the 19th century, also known as the [[energy transformation]]. Then, the [[thermodynamics]] of this century, by [[Rudolf Clausius]], [[Josiah Willard Gibbs|Josiah Gibbs]] and others, established the ''system'' [[reference model]] as a formal scientific object.

Similar ideas are found in [[Learning theory (education)|learning theories]] that developed from the same fundamental concepts, emphasising how understanding results from knowing concepts both in part and as a whole. In fact, Bertalanffy's organismic psychology paralleled the learning theory of [[Jean Piaget]].<ref name="GST">[[Ludwig von Bertalanffy|von Bertalanffy, Ludwig]]. [1968] 1976. ''General System Theory: Foundations, Development, Applications'' (rev. ed.). New York: George Braziller. {{ISBN|0-8076-0453-4}}.</ref> Some consider interdisciplinary perspectives critical in breaking away from [[industrial age]] models and thinking, wherein history represents history and math represents math, while the arts and sciences [[Academic specialization|specialization]] remain separate and many treat teaching as [[behaviorist]] conditioning.<ref>see Steiss 1967; Buckley, 1967.</ref>

The contemporary work of [[Peter Senge]] provides detailed discussion of the commonplace critique of educational systems grounded in conventional assumptions about learning,<ref>{{Cite book |last=Senge |first=Peter., Ed |title=Schools That Learn: A Fifth Discipline Fieldbook for Educators, Parents, and Everyone Who Cares About Education. |publisher=Doubleday Dell Publishing Group. |year=2000 |location=New York |pages=27–49}}</ref> including the problems with fragmented knowledge and lack of holistic learning from the "machine-age thinking" that became a "model of school separated from daily life." In this way, some systems theorists attempt to provide alternatives to, and evolved ideation from orthodox theories which have grounds in classical assumptions, including individuals such as [[Max Weber]] and [[Émile Durkheim]] in sociology and [[Frederick Winslow Taylor]] in [[scientific management]].<ref>Bailey, 1994, pp. 3–8; see also Owens, 2004.</ref> The theorists sought holistic methods by developing systems concepts that could integrate with different areas.

Some may view the contradiction of [[reductionism]] in conventional theory (which has as its subject a single part) as simply an example of changing assumptions. The emphasis with systems theory shifts from parts to the organization of parts, recognizing interactions of the parts as not static and constant but dynamic processes. Some questioned the conventional [[closed system]]s with the development of [[open system (systems theory)|open systems]] perspectives. The shift originated from [[Absolute (philosophy)|absolute]] and universal authoritative principles and knowledge to relative and general [[concept]]ual and [[perceptual]] knowledge<ref>Bailey 1994, pp. 3–8.</ref> and still remains in the tradition of theorists that sought to provide means to organize human life. In other words, theorists rethought the preceding [[history of ideas]]; they did not lose them. Mechanistic thinking was particularly critiqued, especially the industrial-age mechanistic [[metaphor]] for the mind from [[interpretation (philosophy)|interpretation]]s of [[Newtonian mechanics]] by [[Age of Enlightenment|Enlightenment]] philosophers and later psychologists that laid the foundations of modern organizational theory and management by the late 19th century.<ref>Bailey, 1994; Flood, 1997; Checkland, 1999; Laszlo, 1972.</ref>

===Founding and early development===
Where assumptions in Western science from [[Plato]] and [[Aristotle]] to [[Isaac Newton]]'s ''[[Philosophiæ Naturalis Principia Mathematica|Principia]]'' (1687) have historically influenced all areas from the [[Hard Science|hard]] to [[Social science|social]] sciences (see, [[David Easton]]'s seminal development of the "[[political system]]" as an analytical construct), the original systems theorists explored the implications of 20th-century advances in terms of systems.

Between 1929 and 1951, [[Robert Maynard Hutchins]] at the [[University of Chicago]] had undertaken efforts to encourage innovation and interdisciplinary research in the social sciences, aided by the [[Ford Foundation]] with the university's interdisciplinary [[Division of the Social Sciences (University of Chicago)|Division of the Social Sciences]] established in 1931.<ref name=Hammond />{{rp|5–9}}

Many early systems theorists aimed at finding a general systems theory that could explain all systems in all fields of science.

"[[#General systems research and systems inquiry|General systems theory]]" (GST; [[German language|German]]: ''allgemeine Systemlehre'') was coined in the 1940s by [[Ludwig von Bertalanffy]], who sought a new approach to the study of [[living systems]].<ref name=":0">Montuori, A. 2011. "Systems Approach." pp. 414–421 in ''Encyclopedia of Creativity'' (2nd ed.). Academic Press. {{doi|10.1016/B978-0-12-375038-9.00212-0}}.</ref> Bertalanffy developed the theory via lectures beginning in 1937 and then via publications beginning in 1946.<ref name=":2">[[Karl Ludwig von Bertalanffy|von Bertalanffy, Karl Ludwig]]. [1967] 1970. ''Robots, Men and Minds: Psychology in the Modern World'' (1st ed.), translated by H-J. Flechtner. Düsseldorf: Econ Verlag GmbH. p. 115.</ref> According to [[Mike Jackson (systems scientist)|Mike C. Jackson]] (2000), Bertalanffy promoted an embryonic form of GST as early as the 1920s and 1930s, but it was not until the early 1950s that it became more widely known in scientific circles.<ref name=":3">[[Mike Jackson (systems scientist)|Mike C. Jackson]]. 2000. ''Systems Approaches to Management''. London, England: Springer.</ref>

Jackson also claimed that Bertalanffy's work was informed by [[Alexander Bogdanov]]'s three-volume ''[[Tectology]]'' (1912–1917), providing the conceptual base for GST.<ref name=":3" /> A similar position is held by [[Richard Mattessich]] (1978) and [[Fritjof Capra]] (1996). Despite this, Bertalanffy never even mentioned Bogdanov in his works.

The systems view was based on several fundamental ideas. First, all phenomena can be viewed as a web of relationships among elements, or a [[system]]. Second, all systems, whether [[electrical]], [[biological]], or [[social system|social]], have common [[patterns]], [[behavior]]s, and [[Property (philosophy)|properties]] that the observer can analyze and use to develop greater insight into the behavior of complex phenomena and to move closer toward a unity of the sciences. System philosophy, methodology and application are complementary to this science.<ref name=":1" />

Cognizant of advances in science that questioned classical assumptions in the organizational sciences, Bertalanffy's idea to develop a theory of systems began as early as the [[interwar period]], publishing "An Outline for General Systems Theory" in the ''[[British Journal for the Philosophy of Science]]'' by 1950.<ref>[[Ludwig von Bertalanffy|von Bertalanffy, Ludwig]]. 1950. "An Outline for General Systems Theory." ''[[British Journal for the Philosophy of Science]]'' 1(2).</ref>

In 1954, von Bertalanffy, along with [[Anatol Rapoport]], [[Ralph W. Gerard]], and [[Kenneth Boulding]], came together at the [[Center for Advanced Study in the Behavioral Sciences]] in Palo Alto to discuss the creation of a "society for the advancement of General Systems Theory." In December that year, a meeting of around 70 people was held in [[Berkeley, California|Berkeley]] to form a society for the exploration and development of GST.<ref name=":4">{{Cite web|title=History|url=https://www.isss.org/history/|access-date=2021-03-13|website=www.isss.org|archive-date=2021-05-10|archive-url=https://web.archive.org/web/20210510215818/https://www.isss.org/history/|url-status=live}}</ref> The [[Society for General Systems Research]] (renamed the International Society for Systems Science in 1988) was established in 1956 thereafter as an affiliate of the [[American Association for the Advancement of Science]] (AAAS),<ref name=":4" /> specifically catalyzing systems theory as an area of study. The field developed from the work of Bertalanffy, Rapoport, Gerard, and Boulding, as well as other theorists in the 1950s like [[William Ross Ashby]], [[Margaret Mead]], [[Gregory Bateson]], and [[C. West Churchman]], among others.

Bertalanffy's ideas were adopted by others, working in mathematics, psychology, biology, [[game theory]], and [[social network analysis]]. Subjects that were studied included those of [[complexity]], [[self-organization]], [[connectionism]] and [[adaptive systems]]. In fields like [[cybernetics]], researchers such as Ashby, [[Norbert Wiener]], [[John von Neumann]], and [[Heinz von Foerster]] examined complex systems mathematically; Von Neumann discovered [[cellular automata]] and self-reproducing systems, again with only pencil and paper. [[Aleksandr Lyapunov]] and [[Jules Henri Poincaré]] worked on the foundations of [[chaos theory]] without any [[computer]] at all. At the same time, [[Howard T. Odum]], known as a radiation ecologist, recognized that the study of general systems required a language that could depict [[energy|energetics]], [[thermodynamics]] and [[Kinetics (physics)|kinetics]] at any system scale. To fulfill this role, Odum developed a general system, or [[universal language]], based on the circuit language of [[electronics]], known as the [[Energy Systems Language]].

The [[Cold War]] affected the research project for systems theory in ways that sorely disappointed many of the seminal theorists. Some began to recognize that theories defined in association with systems theory had deviated from the initial general systems theory view.<ref>{{Cite journal |last=Hull |first=D. L. |date=1970 |title=Systemic Dynamic Social Theory. |journal=Sociological Quarterly |volume=11 |issue=3 |pages=351–363 |doi=10.1111/j.1533-8525.1970.tb00778.x}}</ref> Economist Kenneth Boulding, an early researcher in systems theory, had concerns over the manipulation of systems concepts. Boulding concluded from the effects of the Cold War that abuses of [[Political power|power]] always prove consequential and that systems theory might address such issues.<ref name=Hammond />{{rp|229–233}} Since the end of the Cold War, a renewed interest in systems theory emerged, combined with efforts to strengthen an [[ethical]]<ref>Ludwig von Bertalanffy. 1968. ''General System theory: Foundations, Development, Applications''.</ref> view on the subject.

In sociology, systems thinking also began in the 20th century, including [[Talcott Parsons]]' [[Action theory (sociology)|action theory]]<ref name=":5">Rudolf Stichweh (2011), "[http://www.fiw.uni-bonn.de/demokratieforschung/personen/stichweh/pdfs/80_stw_systems-theory-international-encyclopedia-of-political-science_2.pdf Systems Theory] {{Webarchive|url=https://web.archive.org/web/20160307050846/https://www.fiw.uni-bonn.de/demokratieforschung/personen/stichweh/pdfs/80_stw_systems-theory-international-encyclopedia-of-political-science_2.pdf|date=2016-03-07}}", in:y.</ref> and [[Niklas Luhmann]]'s [[Social system#Niklas Luhmann|social systems theory]].<ref>{{cite book|last=Luhmann|first=Niklas|title=Soziale Systeme: Grundriß einer allgemeinen Theorie|date=1984|publisher=Suhrkamp}}</ref><ref>Bertrand Badie et al. (eds.), ''International Encyclopedia of Political Science''. Sage New York.</ref> According to Rudolf Stichweh (2011):<ref name=":5" />{{Rp|2}}<blockquote>Since its beginnings the [[social science]]s were an important part of the establishment of systems theory... [T]he two most influential suggestions were the comprehensive sociological versions of systems theory which were proposed by Talcott Parsons since the 1950s and by Niklas Luhmann since the 1970s.</blockquote>Elements of systems thinking can also be seen in the work of [[James Clerk Maxwell]], particularly [[control theory]].

==General systems research and systems inquiry==
Many early systems theorists aimed at finding a general systems theory that could explain all systems in all fields of science. [[Ludwig von Bertalanffy]] began developing his 'general systems theory' via lectures in 1937 and then via publications from 1946.<ref name=":2" /> The concept received extensive focus in his 1968 book, ''General System Theory: Foundations, Development, Applications''.<ref name="GST" />

There are many definitions of a general system, some properties that definitions include are: an overall [[Teleology|goal of the system]], [[Mereology|parts of the system and relationships between these parts]], and [[emergent properties]] of the interaction between the parts of the system that are not performed by any part on its own.<ref name=":6">{{Cite book |last=Skyttner |first=Lars |title=General systems theory : problems, perspectives, practice |date=2005 |publisher=World Scientific |isbn=978-981-277-475-0 |edition=2nd |location=Hackensack, NJ |oclc=181372125 }}</ref>{{Rp|page=58}} [[Derek Hitchins]] defines a system in terms of [[Entropy (information theory)|entropy]] as a collection of parts and relationships between the parts where the parts of their interrelationships decrease entropy.<ref name=":6" />{{Rp|page=58}}

Bertalanffy aimed to bring together under one heading the organismic science that he had observed in his work as a biologist. He wanted to use the word ''system'' for those principles that are common to systems in general. In ''General System Theory'' (1968), he wrote:<ref name="GST" />{{RP|32}}

{{blockquote|[T]here exist models, principles, and laws that apply to generalized systems or their subclasses, irrespective of their particular kind, the nature of their component elements, and the relationships or "forces" between them. It seems legitimate to ask for a theory, not of systems of a more or less special kind, but of universal principles applying to systems in general.|}}

In the preface to von Bertalanffy's ''Perspectives on General System Theory'', [[Ervin László]] stated:<ref name=":1">[[Ervin László|László, Ervin]]. 1974. "Preface" in ''Perspectives on General System Theory'', by L. von Bertalanffy, edited by Edgar Taschdjian. New York: George Braziller.</ref>

{{blockquote|Thus when von Bertalanffy spoke of Allgemeine Systemtheorie it was consistent with his view that he was proposing a new perspective, a new way of doing science. It was not directly consistent with an interpretation often put on "general system theory", to wit, that it is a (scientific) "theory of general systems." To criticize it as such is to shoot at straw men. Von Bertalanffy opened up something much broader and of much greater significance than a single theory (which, as we now know, can always be falsified and has usually an ephemeral existence): he created a new paradigm for the development of theories.}}

Bertalanffy outlines systems inquiry into three major domains: [[philosophy]], [[science]], and [[technology]]. In his work with the Primer Group, [[Béla H. Bánáthy]] generalized the domains into four integratable domains of systemic inquiry:

# philosophy: the [[ontology]], [[epistemology]], and [[axiology]] of systems
# theory: a set of interrelated concepts and principles applying to all systems
# methodology: the set of models, strategies, methods and tools that instrumentalize systems theory and philosophy
# application: the application and interaction of the domains

These operate in a recursive relationship, he explained; integrating 'philosophy' and 'theory' as knowledge, and 'method' and 'application' as action; systems inquiry is thus knowledgeable action.<ref>{{Cite web|url=http://projects.isss.org/doku.php|title=start [ProjectsISSS]|website=projects.isss.org|access-date=2021-04-07|archive-date=2021-04-13|archive-url=https://web.archive.org/web/20210413003925/http://projects.isss.org/doku.php|url-status=live}}</ref>{{failed verification|date=May 2022}}

===Properties of general systems===
General systems may be split into a [[hierarchy]] of systems, where there is less interactions between the different systems than there is the components in the system. The alternative is [[heterarchy]] where all components within the system interact with one another.<ref name=":6" />{{Rp|page=65}} Sometimes an entire system will be represented inside another system as a part, sometimes referred to as a holon.<ref name=":6" /> These hierarchies of system are studied in [[hierarchy theory]].<ref name=":7" /> The amount of interaction between parts of systems higher in the hierarchy and parts of the system lower in the hierarchy is reduced. If all the parts of a system are tightly [[Coupling|coupled]] (interact with one another a lot) then the system cannot be decomposed into different systems. The amount of coupling between parts of a system may differ temporally, with some parts interacting more often than other, or for different processes in a system.<ref>{{cite book |doi=10.1007/978-94-007-7470-4_24 |chapter=Hierarchy Theory: An Overview |title=Linking Ecology and Ethics for a Changing World |date=2013 |last1=Wu |first1=Jianguo |pages=281–301 |isbn=978-94-007-7469-8 }}</ref>{{Rp|page=293}} [[Herbert A. Simon]] distinguished between decomposable, nearly decomposable and nondecomposable systems.<ref name=":6" />{{Rp|page=72}}

[[Russell L. Ackoff]] distinguished general systems by how their goals and subgoals could change over time. He distinguished between goal-maintaining, [[Goal seeking|goal-seekin'''g''']], multi-goal and reflective (or goal-changing) systems.<ref name=":6" />{{Rp|page=73}}

==System types and fields==

===Theoretical fields===
{{prose|section|date=October 2022}}
{{Main|List of types of systems theory}}
* [[Chaos theory]]
* [[Complex system]]
* [[Control theory]]
* [[Dynamical systems theory]]
* [[Earth system science]]
* [[Ecological systems theory]]
* [[Industrial ecology]]
* [[Living systems theory]]<ref name=":7">{{cite book |doi=10.1016/B978-0-12-375000-6.00323-2 |chapter=Sex Roles |title=Encyclopedia of Human Behavior |date=2012 |last1=Sinnott |first1=J.D. |last2=Rabin |first2=J.S. |pages=411–417 |isbn=978-0-08-096180-4 }}</ref>
* [[Sociotechnical system]]
* [[Systemics]]
* [[Telecoupling]]
* [[Urban metabolism]]
* [[World-systems theory]]

====Cybernetics====
{{Main|Cybernetics}}

[[Cybernetics]] is the study of the [[communication]] and control of regulatory [[feedback]] both in living and lifeless systems (organisms, organizations, machines), and in combinations of those. Its focus is how anything (digital, mechanical or biological) controls its behavior, processes information, reacts to information, and changes or can be changed to better accomplish those three primary tasks.

The terms ''systems theory'' and ''cybernetics'' have been widely used as synonyms. Some authors use the term ''cybernetic'' systems to denote a proper subset of the class of general systems, namely those systems that include [[feedback loops]]. However, [[Gordon Pask]]'s differences of eternal interacting actor loops (that produce finite products) makes general systems a proper subset of cybernetics. In cybernetics, complex systems have been examined mathematically by such researchers as [[W. Ross Ashby]], [[Norbert Wiener]], [[John von Neumann]], and [[Heinz von Foerster]].

Threads of cybernetics began in the late 1800s that led toward the publishing of seminal works (such as Wiener's ''[[Cybernetics: Or Control and Communication in the Animal and the Machine|Cybernetics]]'' in 1948 and [[Ludwig von Bertalanffy|Bertalanffy]]'s ''General System Theory'' in 1968). Cybernetics arose more from engineering fields and GST from biology. If anything, it appears that although the two probably mutually influenced each other, cybernetics had the greater influence. Bertalanffy specifically made the point of distinguishing between the areas in noting the influence of cybernetics:<blockquote>Systems theory is frequently identified with cybernetics and control theory. This again is incorrect. Cybernetics as the theory of control mechanisms in technology and nature is founded on the concepts of information and feedback, but as part of a general theory of systems.... [T]he model is of wide application but should not be identified with 'systems theory' in general ... [and] warning is necessary against its incautious expansion to fields for which its concepts are not made.<ref name="GST" />{{Rp|17–23}}</blockquote>Cybernetics, [[catastrophe theory]], [[chaos theory]] and [[Complex systems#Complexity and chaos theory|complexity theory]] have the common goal to explain complex systems that consist of a large number of mutually interacting and interrelated parts in terms of those interactions. [[Cellular automaton|Cellular automata]], [[neural network]]s, [[artificial intelligence]], and [[artificial life]] are related fields, but do not try to describe general (universal) complex (singular) systems. The best context to compare the different "C"-Theories about complex systems is historical, which emphasizes different tools and methodologies, from [[pure mathematics]] in the beginning to pure [[computer science]] today. Since the beginning of chaos theory, when [[Edward Lorenz]] accidentally discovered a [[strange attractor]] with his computer, computers have become an indispensable source of information. One could not imagine the study of complex systems without the use of computers today.

===System types===
{{prose|section|date=October 2022}}
* [[Biological system|Biological]]
** [[Anatomy|Anatomical systems]]
*** [[Nervous system|Nervous]]
**** [[Sensory system|Sensory]]
** [[Social ecological model#Bronfenbrenner's ecological framework for human development|Ecological systems]]
** [[Living systems]]
* [[Complex system|Complex]]
** [[Complex adaptive system]]
* [[Conceptual system|Conceptual]]
** [[Coordinate system|Coordinate]]
** [[Deterministic system (philosophy)|Deterministic]] (philosophy)
** [[Digital ecosystem]]
** [[Experimental system|Experimental]]
** [[Writing system|Writing]]
* [[Coupled human–environment system|Coupled human–environment]]
* [[Database system|Database]]
* [[Deterministic system|Deterministic]] (science)
* [[Mathematical system theory|Mathematical]]
** [[Dynamical system]]
** [[Formal system]]
* [[Energy system|Energy]]
* [[Holarchical System|Holarchical]]
* [[Information system|Information]]
* [[System of measurement|Measurement]]
** [[Imperial System|Imperial]]
** [[Metric system|Metric]]
* [[Multi-agent system|Multi-agent]]
* [[Nonlinear system|Nonlinear]]
* [[Operating system|Operating]]
* [[Planetary system|Planetary]]
* [[Social system|Social]]
** [[Cultural system|Cultural]]
** [[Economic system|Economic]]
** [[List of national legal systems|Legal]]
** [[Political system|Political]]
* [[Star system|Star]]

====Complex adaptive systems====
{{Main|Complex adaptive system}}
Complex adaptive systems (CAS), coined by [[John Henry Holland|John H. Holland]], [[Murray Gell-Mann]], and others at the interdisciplinary [[Santa Fe Institute]], are special cases of [[complex system]]s: they are ''complex'' in that they are diverse and composed of multiple, interconnected elements; they are ''adaptive'' in that they have the capacity to change and learn from experience.

In contrast to [[control system]]s, in which [[negative feedback]] dampens and reverses disequilibria, CAS are often subject to [[positive feedback]], which magnifies and perpetuates changes, converting local irregularities into global features.

==See also==
{{Portal|Systems science
}}
{{cols|colwidth=17em}}
* [[Glossary of systems theory]]
* [[List of types of systems theory]]

* [[Autonomous agency theory]]
* [[Bibliography of sociology]]
* [[Cellular automata]]
* [[Chaos theory]]
** [[Complex systems#Complexity and chaos theory|Complexity]]
* [[Dependency theory]]
* [[Emergence]]
* [[Engaged theory]]
* [[Fractal]]
* [[Grey box model]]
* [[Hierarchy theory]]
* [[Irreducible complexity]]
* [[Meta-systems]]
* [[Multidimensional systems]]
* [[Open and closed systems in social science]]
* [[Pattern language#Usage|Pattern language]]
* [[Recursion (computer science)]]
* [[Reductionism]]
* [[Redundancy (engineering)]]
* [[Reversal theory]]
* [[Social rule system theory]]
* [[Sociology and complexity science]]
* [[Sociotechnical system]]
* [[Structuralist economics]]
* [[Structure–organization–process]]
* [[System identification]]
* [[Systemantics]]
* [[Systematics – study of multi-term systems]]
* [[Systemics]]
* [[Systemography]]
* [[Systems science]]
* [[Tektology]]
* [[Theoretical ecology]]
* [[User-in-the-loop]]
* [[Viable system theory]]
* [[Viable systems approach]]
* [[World-systems theory]]
{{colend}}

===Organizations===
* [[List of systems sciences organizations]]

==References==
{{Reflist|30em}}

==Further reading==
{{refbegin |30em}}
* {{cite book |last=Ashby |first=W. Ross |author-link=W. Ross Ashby |title=An Introduction to Cybernetics |year=1956 |publisher=Chapman & Hall|oclc=522174}}
* {{cite book |last=Ashby |first=W. Ross |author-link=W. Ross Ashby |title=Design for a Brain: The Origin of Adaptive Behavior |edition=2nd |year=1970 |publisher=Chapman & Hall|oclc=19378401}}
* {{cite book |last1=Bateson |first1=Gregory |author-link1=Gregory Bateson |last2=Bateson|first2=Mary C.|title=Steps to an Ecology of Mind |orig-year=1972 |year=2000|edition=University of Chicago Press|publisher=University of Chicago Press|oclc=42295815|isbn=9780226039060}}
* {{cite book |last=von Bertalanffy |first=Ludwig |author-link=Ludwig von Bertalanffy |title=General System Theory |year=1968 |publisher=George Braziller |location=New York}}
* {{cite book |last=Burks |first=Arthur |author-link=Arthur Burks |title=Essays on Cellular Automata |year=1970 |publisher=University of Illinois Press}}
* {{cite book |last=Cherry |first=Colin |author-link=Colin Cherry |title=On Human Communication |year=1957 |publisher=The MIT Press |location=Cambridge}}
* {{cite book |last=Churchman |first=C. West |author-link=C. West Churchman |title=The Design of Inquiring Systems |year=1971 |publisher=Basic Books |location=New York}}
* {{cite book |last=Checkland |first=Peter |author-link=Peter Checkland |title=Systems Thinking, Systems Practice |year=1999 |publisher=Wiley}}
* {{cite book |last=Gleick |first=James |author-link=James Gleick |title=Chaos: Making a New Science |year=1997 |publisher=Random House}}
* {{cite book |last=Haken |first=Hermann |author-link=Hermann Haken |title=Synergetics: An Introduction |edition=3rd |year=1983 |publisher=Springer}}
* {{cite book |last=Holland |first=John H. |author-link=John H. Holland |title=Adaptation in Natural and Artificial Systems |year=1992 |publisher=The MIT Press |location=Cambridge}}
* {{cite book |last=Luhmann |first=Niklas |author-link=Niklas Luhmann |title=Introduction to Systems Theory |year=2013 |publisher=Polity}}
* {{cite book |last=Macy |first=Joanna |author-link=Joanna Macy |title=Mutual Causality in Buddhism and General Systems Theory |year=1991 |publisher=SUNY Press}}
* {{cite book |last1=Maturana |first1=Humberto |author-link1=Humberto Maturana |title=Autopoiesis and Cognition |year=1980 |publisher=Springer Science & Business Media |first2=Francisco |last2=Varela}}
* {{cite book |last=Miller |first=James Grier |author-link=James Grier Miller |title=Living Systems |year=1978 |publisher=McGraw-Hill}}
* {{cite book |last=von Neumann |first=John |author-link=John von Neumann |title=Cerebral Mechanisms in Behavior |year=1951 |chapter=The General and Logical Theory of Automata |pages=1–41}}
* {{cite journal |last=von Neumann |first=John |author-link=John von Neumann |title=Probabilistic Logics and the Synthesis of Reliable Organisms from Unreliable Components |journal=Automata Studies |volume=34 |year=1956 |pages=43–98}}
* {{cite book |last=von Neumann |first=John |author-link=John von Neumann |title=Theory of Self-Reproducing Automata |year=1966 |publisher=Illinois University Press |editor1-first=Arthur|editor-last1=Burks}}
* {{cite book |last=Parsons |first=Talcott |author-link=Talcott Parsons |title=The Social System |year=1951 |publisher=The Free Press}}
* {{cite book |last=Prigogine |first=Ilya |author-link=Ilya Prigogine |title=From Being to Becoming |year=1980 |publisher=W. H. Freeman & Co}}
* {{cite journal |last=Simon |first=Herbert A. |author-link=Herbert A. Simon |title=The Architecture of Complexity |journal=Proceedings of the American Philosophical Society |volume=106 |year=1962}}
* {{cite book |last=Simon |first=Herbert A. |author-link=Herbert A. Simon |title=The Sciences of the Artificial |edition=3rd |volume=136 |year=1996 |publisher=The MIT Press}}
* {{cite book |last1=Shannon |first1=Claude |author-link1=Claude Shannon |first2=Warren |last2=Weaver |title=The Mathematical Theory of Communication |year=1998 |isbn=0-252-72546-8|orig-date=1st Pub. 1949}}
* {{cite journal |last=Shannon |first=Claude |author-link=Claude Shannon |title=A Mathematical Theory of Communication |journal=Bell System Technical Journal |volume=27 |issue=3 |year=1948 |pages=379–423 |doi=10.1002/j.1538-7305.1948.tb01338.x |url=https://ieeexplore.ieee.org/document/6773024|url-access=subscription }}
* {{cite book |last=Thom |first=René |author-link=René Thom |title=Structural Stability and Morphogenesis |year=1972 |publisher=Addison-Wesley |location=Reading, Massachusetts}}
* {{cite book |last=Volk |first=Tyler |author-link=Tyler Volk |title=Metapatterns: Across Space, Time, and Mind |year=1995 |publisher=Columbia University Press |isbn=978-0-231-53262-4 |url=https://cup.columbia.edu/book/metapatterns/9780231067508}}
* {{cite journal |last=Weaver |first=Warren |author-link=Warren Weaver |title=Science and Complexity |journal=The American Scientist |year=1948 |volume=36 |issue=4 |pages=536–544 |pmid=18882675 }}
* {{cite book |last=Wiener |first=Norbert |author-link=Norbert Wiener |title=Cybernetics: Or the Control and Communication in the Animal and the Machine |edition=2nd |year=1965 |publisher=The MIT Press}}
* {{cite book |last=Wolfram |first=Stephen |author-link=Stephen Wolfram |title=A New Kind of Science |year=2002 |publisher=Wolfram Media}}
* {{cite journal |last=Zadeh |first=Lofti |author-link=Lofti Zadeh |title=From Circuit Theory to System Theory |journal=Proceedings of the IRE |volume=50 |issue=5 |year=1962 |pages=856–865 |doi=10.1109/JRPROC.1962.288302 }}
{{refend}}

==External links==
{{Sister project links|Systems theory}}
* {{wikidata-inline}}
* [https://en.wikiversity.org/wiki/Systems_Thinking Systems Thinking] at Wikiversity
* [http://pespmc1.vub.ac.be/SYSTHEOR.html Systems theory] at Principia Cybernetica Web
* [https://www.unescap.org/sites/default/files/Introduction%20to%20systems%20thinking%20tools_Eng.pdf Introduction to systems thinking] – 55 slides

'''Organizations'''
* [http://www.isss.org/ International Society for the System Sciences]
* [http://www.necsi.edu/ New England Complex Systems Institute]
* [http://www.systemdynamics.org/ System Dynamics Society]

{{Systems}}
{{Digital Humanities}}
{{Computer modeling}}
{{Authority control}}

[[Category:Systems theory| ]]
[[Category:Emergence]]
[[Category:Interdisciplinary subfields of sociology]]
[[Category:Complex systems theory]]
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