Editing Niklas Luhmann (section)

===Systems theory===
Luhmann's systems theory focuses on three topics, which are interconnected in his entire work.<ref>Niklas Luhmann (1975), "Systemtheorie, Evolutionstheorie und Kommunikationstheorie", in: ''Soziologische Gids'' 22 3. pp.154–168.</ref>
# Systems theory as societal theory
# Communication theory and
# Evolution theory
The core element of Luhmann's theory pivots around the problem of the contingency of meaning, and thereby it becomes a theory of [[communication]]. Social systems are systems of communication, and society is the most encompassing social system. Being the social system that comprises all (and only) communication, today's society is a world society.<ref name="Luhmann 1982 pp. 131–138" /> A [[system]] is defined by a boundary between itself and its [[social environment|environment]], dividing it from an infinitely complex, or (colloquially) chaotic, exterior. The interior of the system is thus a zone of reduced complexity: communication within a system operates by selecting only a limited amount of all information available outside. This process is also called "reduction of complexity". The criterion according to which information is selected and processed is meaning (in German, ''Sinn''). Meaning being thereby referral from one set of potential space to another set of potential space. Both social systems and psychic systems (see below for an explanation of this distinction) operate by processing meaning.

Furthermore, each system has a distinctive identity that is constantly reproduced in its communication and depends on what is considered meaningful and what is not. If a system fails to maintain that identity, it ceases to exist as a system and dissolves back into the environment it emerged from. Luhmann called this process of reproduction from elements previously filtered from an over-complex environment [[autopoiesis]] (pronounced "auto-poy-E-sis"; literally: self-creation), using a term coined in [[cognitive biology]] by Chilean thinkers [[Humberto Maturana]] and [[Francisco Varela]]. Social systems are ''operationally closed'' in that while they use and rely on resources from their environment, those resources do not become part of the systems' operation. Both thought and digestion are important preconditions for communication, but neither appears in communication as such.<ref name="Luhmann 1982 pp. 131–138">{{cite journal | last=Luhmann | first=Niklas | title=The World Society as a Social System | journal=International Journal of General Systems | publisher=Informa UK Limited | volume=8 | issue=3 | year=1982 | issn=0308-1079 | doi=10.1080/03081078208547442 | pages=131–138}}</ref>

Maturana, however, argued very vocally that this appropriation of autopoietic theory was conceptually unsound, as it presupposes the autonomy of communications from actual persons. That is, by describing social systems as operationally closed networks of communications, Luhmann (according to Maturana) ignores the fact that communications presuppose human communicators. Autopoiesis only applies to networks of processes that reproduce themselves,<ref name="Varela Maturana Uribe 1974 pp. 187–196">{{cite journal | last1=Varela | first1=F.G. | last2=Maturana | first2=H.R. | last3=Uribe | first3=R. | title=Autopoiesis: The organization of living systems, its characterization and a model | journal=Biosystems | publisher=Elsevier BV | volume=5 | issue=4 | year=1974 | issn=0303-2647 | doi=10.1016/0303-2647(74)90031-8 | pages=187–196| pmid=4407425 | bibcode=1974BiSys...5..187V }}</ref> but communications are reproduced by humans. For this reason, the analogy from biology to sociology does not, in this case, hold.<ref name="Maturana 2004 p. ">{{cite book | last=Maturana | first=Humberto | title=From being to doing : the origins of the biology of cognition | publisher=Carl Auer Verlag | publication-place=Heidelberg | year=2004 | isbn=3-89670-448-6 | oclc=59207392 | pages=105–108}}</ref> On the other hand, Luhmann explicitly stressed that he does not refer to a "society without humans", but to the fact that communication is autopoietic. Communication is made possible by human bodies and consciousness,<ref>Luhmann, N. ''Theory of Society, Vol. 1''. Stanford University Press, 2012, pp.56.</ref> but this does not make communication operationally open. To "participate" in communication, one must be able to render one's thoughts and perceptions into elements of communication. This can only ever occur as a communicative operation (thoughts and perceptions cannot be directly transmitted) and must therefore satisfy internal system conditions that are specific to communication: intelligibility, reaching an addressee and gaining acceptance.<ref>Luhmann, N. ''Social Systems''. Stanford University Press, 1995, p. 158.</ref>

Luhmann likens the operation of autopoiesis (the filtering and processing of information from the environment) to a [[program (management)|program]]; making a series of logical distinctions (in German, ''Unterscheidungen''). Here, Luhmann refers to the British mathematician [[G. Spencer-Brown]]'s logic of distinctions that Maturana and Varela had earlier identified as a model for the functioning of any cognitive process. The supreme criterion guiding the "self-creation" of any given system is a defining [[binary code]]. This binary code is not to be confused with a computer's operation: Luhmann (following Spencer-Brown and [[Gregory Bateson]]) assumes that auto-referential systems are continuously confronted with the dilemma of disintegration/continuation. This dilemma is framed with an ever-changing set of available choices; every one of those potential choices can be the system's selection or not (a binary state, selected/rejected). The influence of Spencer-Brown's book, ''[[Laws of Form]]'', on Luhmann can hardly be overestimated.

Although Luhmann first developed his understanding of social systems theory under Parsons' influence, he soon moved away from the Parsonian concept. The most important difference is that Parsons framed systems as forms of [[Action theory (sociology)|action]], in accordance with the [[AGIL paradigm]]. Parsons' systems theory treats systems as [[Open system (systems theory)|operationally open]], and interactive through an [[Input/output|input and output schema]]. Influenced by [[second-order cybernetics]], Luhmann instead treats systems as [[autopoietic]] and [[Open and closed systems in social science#Sociology|operationally closed]].<ref>Luhmann, N. ''Social Systems''. Stanford University Press, 1995.</ref><ref>Luhmann, N. ''Introduction to Systems Theory''. Polity, 2012.</ref> Systems must continually construct themselves and their perspective of reality through processing the distinction between system and [[Environment (systems)|environment]], and self-reproduce themselves as the product of their own elements. Social systems are defined by Luhmann not as action but as [[Recursion|recursive]] communication. Modern society is defined as a world system consisting of the sum total of all communication happening at once,<ref>Luhmann, N. ''Theory of Society, Vol. 1''. Stanford University Press, 2012, pp. 83–99.</ref> and individual function systems (such as the economy, politics, science, love, art, the media, etc.) are described as social subsystems which have "outdifferentiated" from the social system and achieved their own operational closure and autopoiesis.<ref>Luhmann, N. ''Theory of Society, Vol. 2''. Stanford University Press, 2013, pp. 65ff.</ref>

Another difference is that Parsons asks how certain subsystems contribute to the functioning of overall society. Luhmann starts with the [[Differentiation (sociology)|differentiation of the systems]] themselves out of a nondescript environment. While he does observe how certain systems fulfill functions that contribute to "society" as a whole, he dispenses with the assumption of ''a priori'' [[Collective consciousness|cultural or normative consensus]] or "complimentary purpose" which was common to Durkheim and Parsons' conceptualization of a social function.<ref>Luhmann, N. ''Theory of Society, Vol. 1''. Stanford University Press, 2012, p. 6.</ref> For Luhmann, functional differentiation is a consequence of selective pressure under temporalized complexity, and it occurs as function systems independently establish their own ecological niches by performing a function.<ref>Luhmann, N. ''Theory of Society, Vol. 1''. Stanford University Press, 2012, esp. pp. 336–343.</ref> Functions are therefore not the coordinated components of the organic social whole, but rather contingent and selective responses to reference problems which obey no higher principle of order and could have been responded to in other ways.

Finally, the systems' autopoietic closure is another fundamental difference from Parsons' concept. Each system works strictly according to its very own code and can observe other systems only by applying its code to their operations. For example, the code of the economy involves the application of the distinction between payment and non-payment. Other system operations appear within the economic field of references only insofar as this economic code can be applied to them. Hence, a political decision becomes an economic operation when it is observed as a government spending money or not. Likewise, a legal judgement may also be an economic operation when settlement of a contractual dispute obliges one party to pay for the goods or services they had acquired. The codes of the economy, politics and law operate autonomously, but their "interpenetration"<ref>Luhmann, N. ''Social Systems''. Stanford University Press, 1995, Chapter 6.</ref> is evident when observing "events"<ref>Luhmann, N. ''Theory of Society, Vol. 2''. Stanford University Press, 2013, p. 93.</ref> which simultaneously involve the participation of more than one system.

One seemingly peculiar, but, within the overall framework, strictly logical, axiom of Luhmann's theory is the human being's position outside the strict boundaries of any social system, as initially developed by Parsons. Consisting of, but not being solely constituted by, "communicative actions" (a reference to [[Jürgen Habermas]]), any social system requires human consciousnesses (personal or psychical systems) as an obviously necessary, but nevertheless environmental resource. In Luhmann's terms, human beings are neither part of society nor of any specific system, just as they are not part of a conversation. People make conversation possible. Luhmann himself once said concisely that he was "not interested in people". That is not to say that people were not a matter for Luhmann, but rather alluding to the scope of the theory where,{{Clarification needed|date=February 2023}} the communicative behavior of people is constituted (but not defined) by the dynamics of the social system, and society is constituted (but not defined) by the communicative behavior of people: society is people's environment, and people are society's environment.

Thus, sociology can explain how persons can change society; the influence of the environment (the people) on a given social system (a society), the so-called ''"structural coupling"'' of ''"partially interpenetrating systems"''. 
In fact Luhmann himself replied to the relevant criticism by stating that, "In fact the theory of autopoietic systems could bear the title ''Taking Individuals Seriously'', certainly more seriously than our humanistic tradition" (Niklas Luhmann, ''Operational Closure and Structural Coupling: The Differentiation of the Legal System'', Cardozo Law Review, vol. 13: 1422). 
Luhmann was devoted to the ideal of non-normative science introduced to sociology in the early 20th century by [[Max Weber]] and later re-defined and defended against its critics by [[Karl Popper]]. However, in an academic environment that never strictly separated descriptive and normative theories of society, Luhmann's sociology has widely attracted criticism from various intellectuals, including [[Jürgen Habermas]].{{Citation needed|date=March 2017}}