The concept of autopoiesis in itself cannot explain a system’s persistence over time. Autopoiesis happens in a moment; it is an event that passes away as soon as it occurs and must be replaced with another operation. But in order for systems to persist or reproduce themselves, structures must emerge. Only structures persist in time. Thus structural coupling complements autopoiesis. Structure is associated with redundancy--repetition of the same kind of event. Systems recognize the same kind of event and incorporate them into structures.
Luhmann borrowed the structurally coupling concept from from Humberto Maturana. As Luhmann writes,
Maturana introduced the concept of structural coupling. The distinction [between this concept and autopoiesis] allows us to say that autopoiesis must function in any case since there would otherwise be no system. At the same time, it also indicates that coupling between system and environment concerns only structures [and not operations] and, as the case may be, everything in the environment that is relevant to these structures. Thus, on earth gravity is coordinated with the musculature of a living being that has to move in order to survive. We can observe a reduction of life chances through the need for movement in correspondingly complex organisms. And we also observe the creation of possibilities for movement, which always emerge in coordination with conditions of life on earth. This is a case of structural coupling. This concept is adjusted to the autopoiesis of the system, which is to say that structural coupling does not interfere with the system’s autopoiesis [my emphasis]. . . There [can be] the destruction of the system by the environment, but the environment does not actively contribute to the maintenance of the system. This is precisely the point of the concept of ‘autopoiesis.’ The causalities that occur between system and environment are located exclusively in the domain of structure coupling. (Intro 85)
In other words, nothing in a system’s environment can cause a specific structural change to happen in the system. The environment can only perturb or destabilize a system, but the system restabilizes itself in its own way. This restabilization is known as autopoiesis.
Luhmann speaks of a simultaneous dependence and exclusion in structural coupling. For instance, the meaning attributed to a sentence cannot depend on what the speaker was thinking or intending when she spoke the sentence. This means that communication is not bound by consciousness, as in the intentions of a speaker. Nor can the meaning of an utterance depend on the blood pressure or cholesterol numbers of the speaker (or any other elements of the organic system of the body). A communication system simply cannot be concerned with all that. As Luhmann puts it, “After all, it is completely unthinkable that communication would have to consider everything that happens physically, chemically, or biologically within all the participants of communication” (Intro 199). Something like cholesterol levels can only be included in a communication system as topic; that is, it has to translated into information.
In order to engage in language-based communication, one must be awake and attending to language. This is a case of structural coupling between a communication system and a consciousness/attention system, also known as the psychic system.
Communication depends on an inclusion/exclusion code; it includes only what is relevant to the ongoing communication, or only what can meaningfully follow on previous communicative events. This is a case of simultaneous dependence and autonomy. Communication depends fundamentally on consciousness, or the conscious awareness of communicators, the attention given to communication, and probably the intention to communicate; however, consciousness is operationally excluded from the communication system.
In other words, communication is structurally coupled to consciousness, but not operationally coupled.
Operational coupling can happen when two systems have access the same operation, which means that the different, autonomous systems must be subsystems of the same system. For example, the health system and the education system are both subsystems of society. And these two subsystems can operationally couple when, for example, a doctor writes a note excusing a patient from school. It is the written communication from doctor to school that constitutes operational coupling. Both systems, being subsystems of society, have access to the operation of communication. However, it’s important to understand that the writing of the note alone is not enough; the note must be read and understood (or even misunderstood) by the school in order to count as communication–and the note be understood as educationally relevance or meaningful. Communication is not an act one person can do alone, unless she is talking to herself or writing for her eyes only, as we do when drafting a paper.
In the example of the doctor and the note, we have a person who is both patient and a student. She can access the medical system and the educational system, but she is not an integral part of either system. For systems are not wholes consisting of parts. This is what it means to say that society consist not of of people but only communication.
It’s important to understand that when two autonomous systems structurally couple, there is not a third system that emerges between them. That is to say, contrary to some sociological theory, the two systems are not integrated. This is because there can be no system with more than one operation. For instance, the political subsystem and the economic system do structurally couple, but they cannot create a third functional system that combines to functions of politics and economic. A third system would cause the two systems to “stick together” and so their autonomy.
A functional system such as the economy is, as the word implies, a function. Functional systems cannot structurally couple without the help of organizations. That is to say, organizations are required to bring about structural coupling because organizations can cross the formal boundaries separating functional system. In other words, organizations can access different functional systems. The state is the most visible organization that operates politically, but the state also operate economically and legally–it can access the economy by spending money and the law by making new laws (legislation) and resolving legal disputes (the courts).
The function of the political subsystem of society to to make collectively binding decisions on matters of general concern, such as whether to go to war, raise taxes, etc. The function of the economic system to handle the problem of scarcity. The state is an organization, not a functional system, but it has has access to a number of functional systems, like the political system, the law, the economy, mass media, etc. This means that organizations facilitate the structurally coupling of functional systems.
When a state spends money, it structurally couples politics and the economy. Also when it passes a law regulating an economic practice, it structurally couples law and the economy. Nonetheless, these functional systems remain distinct.
Systems can be structurally coupled loosely or tightly, and , given how much money states raise and spend, modern politics and economics (where the welfare state comes into being) are very tightly coupled. Tightly coupled systems tend to perturb one another a great deal. For instance, an economic recession can destabilize a state, and the governing party may lose power to the opposition. Or unwise fiscal decisions of a government can perturb the economy and prompt it to restabilize itself.
A case of loose structurally coupling in modern society would be the coupling between religion and politics. It is unlikely that a change in religious doctrine could significantly destabilize a modern state, and it is unlikely that a government decision could significantly destabilize a religion. Which is why the framers of modern constitutional republics took such pains to keep these two politics and religion apart. They didn’t want religious wars that could destroy the political system.
To return communication/social systems in general, communication, as an autopoietic operation, is not available to consciousness or to the organic body. The only operation available to consciousness is sensory perception, which consists of paying attention to its environment. Consciousness generally scans its environment for anything unexpected or dangerous, but I won’t get into that subject right now.
Consciousness attends to its environment, which can be sensory impressions arising from within the body (e.g., a racing heart, a fever, a stomach ache) or external objects and events (i.e., anything seen, heard, felt, or tasted). And the only way a person can put these private experiences into the social system is through language. And, according to Luhmann, actions like jumping up and down and shouting after accidentally striking one’s thumb with a hammer don’t count as language.
The main point to understand is that consciousness is completely excluded from the operation of communication. This is what it means to say that autopoietic systems are operationally closed. Consciousness structurally couples with communication, but consciousness is excluded from the operation of communication; that is to say, consciousness must remain in the environment of the communication system
Consciousness must be structurally coupled to the biological system, or the body. For instance, there can be no consciousness without adequate cerebral blood flow; that is to say, a person cannot attend to or process sensory impressions without a functioning brain. However, the brain is operationally excluded from consciousness. If this wasn’t the case, when a person went to sleep the brain would die. And clearly the brain would die if a person entered a long-term coma. That is to say, brain function does not depend on consciousness, yet consciousness does depend on the brain. This is an asymmetrical relationship.
Even though consciousness directly depends on adequate cerebral blood flow, communication does not. Communication depends only indirectly on the functioning brain. Communication directly depends only on consciousness, and consciousness directly depends on a functioning brain. So consciousness stands between communication and the brain, so to speak. Cerebral blood flow is operationally excluded from the communication system. In other words, the only operation communication can couple with is communication, which can be communication between different subsystems of society (e.g., law and politics). This is operational coupling.
Another way of putting this is that structural coupling implies structural decoupling. If communication can structurally couple with consciousness, it must also be able to decouple; otherwise the two systems would be one. For instance, sentences spoken or written can remain in a communication system as long as they are repeated or recur in further utterances. The “original” speakers and listeners (or writers and readers) can die, and the communication can remain in circulation. It’s true that some human consciousness has to be around to keep the sentence in communicative circulation; however, human consciousnesses (attentive minds) are plentiful and easily replaced. Thus, Luhmann can say that “communication depends completely on consciousness and at the same time excludes it completely” (Intro 199).
A system’s structures are influenced (but never directly caused) by conditions in its environment. Something in the system’s environment can certainly destroy a system (if, for instance a boulder lands on a person’s head or if an asteroid crashes into a planet), but it cannot directly change it in any other way. In other words, there is a not a simple input-out process as in trivial machines. In complex machines, like societies, the “output” cannot be precisely predicted by the “input.” This means that a human being, or any complex organism, does not operate according to simple behaviorist stimulus-response models. In brief, the effect of a particular stimulus on a system depends on the system’s structures.
An example a trivial machine is the the equation 2x=y. If I know what x is, I know what y is. But if two students in a literature class read the same novel (the same input), the essays they write (the output) will obviously not be identical (unless one has plagiarized the other!) because the students do not have the same cognitive or affective structures.
So, after all this work, what is gained by excluding everything except except consciousness from the possibility of structurally coupling with communication? What is the evolutionary compensation?
What is gained is that communication has to depend on one and only one thing in its environment–consciousness. This simplifies matters quite a bit. Communication doesn’t have to directly depend on a properly functioning brain because consciousness depends on that. If that precondition isn’t met, then there is no question of communication anyway; so why worry about it or try to control it? As Luhmann puts it, “The compensation for this exclusion is the total dependence of communication on consciousness, which in turn depends completely on one’s brain, and the brain requires that the organism be alive. . . . [This is a] paradox of simultaneous total dependence and total independence. Communication happens only via consciousness and with the help of consciousness but never operationally as consciousness” (200-201).