Luhmann borrowed the structurally coupling concept 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. . . . 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 . . . 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 structural coupling. (Introduction to Systems Theory, 85)
In other words, nothing in a system’s environment can cause a specific, planned structural change to happen in the system. Systems are structurally self-determined. Systems theory replaces planning with structurally determined evolution.
But what is structural coupling in a more material sense? A horse and a rider structurally couple while the rider is riding the horse. The two entities, clearly, are not bound together to form a Centaur; decoupling is always possible. If the rider wants some technical assistance, she might use a saddle, saddle pad, girth, bridle, reins, bit, stirrups, and more–all of which contribute to structural coupling of the rider and horse. All of the stuff that allows the rider to stay on the horse can be called media. It mediates between horse and rider. Of course, a rider can attempt to ride without a saddle or any other equipment. In this case, the media are the rider’s own muscles and sense of balance, which are things that can be developed with practice. Adopting the language of Deleuze and Guattari, we could also call this an assemblage.
If you have two pieces of pipe that you want to join together, the coupling (or coupler) is the medium.
So structural coupling requires some medium. In the structural coupling between a psychic system and a social system (an interaction system, organization, or function system), the medium is meaning. It might be supposed that the medium is language, but this is not accurate because meaning can form without language. A psychic system responds to a perceived (self-constructed) meaning, even when another psychic system or social system tried to convey a different meaning.
Luhmann also distinguished between medium and form. For example, a writing system consists of a medial substratum of the letters of an alphabet, and these letters can be arranged into an almost infinite variety of meaningful words. The letters are the media and the words are the form. This topic is covered in another post.
Structural coupling complements autopoiesis. The concept of autopoiesis alone cannot explain a system’s persistence over time. Autopoiesis consists of events that pass away as soon as they occur. In order for social systems to persist or reproduce themselves, expectational structures must emerge. Once a system has expectations, it can respond to what happens. This means that an observing system draws a distinction between past and future. If a system experiences itself as persisting over time, this means the system is observing itself using the past/future distinction. So a system can observe itself over time, or a system can observes something else over time. For instance, a person can keep a journal or diary as way to observe herself over time. Or a scientist can keep notes to record changes in some observed phenomenon over time.
Simultaneous Dependence and Exclusion
Luhmann speaks of a simultaneous dependence and exclusion in structural coupling. In the horse-and-rider example, the rider depends on the saddle, reins, bit, stirrups, etc. But these things not permanent parts of the rider or the horse; that is to say, they are excluded from permanent structures of the rider’s body and the horse’s body. In social systems, the meaning attributed (by a social system) to an utterance cannot depend on what the speaker was thinking or intending when she made the utterance. This means that communication is not bound by consciousness, as in the intentions or desires of a speaker. And with respect to organic systems, while a person has to be alive–blood must be flowing, etc.–to make an utterance (which could include talking in one’s sleep), the meaning of an utterance, clearly, doesn’t depend on the blood pressure or any other elements of the speaker’s body. The communication system determines or selects the meaning independent of a speaker’s physiological condition. The point is that communication systems simply cannot be concerned with the intentions or the physiological conditions of a speaker. 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. (Introduction to Systems Theory, 199).
All of that is excluded from communication. Something like blood pressure or cholesterol levels can only be included in a communication system as a topic; that is, it has to be translated into language. But the physiological events in themselves have no meaning.
In order to engage in meaningful communication, a person must be awake and attending to signs (language or some other of kind of sign). This is a case of structural coupling between a communication system and a consciousness (or psychic) system. Communication depends fundamentally on consciousness, or conscious awareness; however, the events that constitute consciousness are operationally excluded from the communication (or social) system. The events happening within the psychic system are too complex to be incorporated into communication. They way a particular psychic system interprets a particular sign cannot be fully understood by another psychic system or a social system. If person A smiles and person B interprets the smile as an insult, there is no way for person A to know what happening in person B’s mind. In fact, person B cannot fully understand why she interprets a particular sign the way she does. The only thing that is needed for communication to happen is for some meaning to be formed, socially or psychologically.
It’s important to understand that when two autonomous systems (e.g., a psychic system and a social system) structurally couple, there is not a third system that emerges through combination. In the horse-and-rider example, the material equipment does not constitute a system. That is to say, contrary to some sociological theory, the structurally coupled systems are not integrated. Two or more psychic systems cannot share the same thoughts, feelings, or perceptions. And while the political system and the economic system do structurally couple, they cannot form a third function system that combines the functions of politics and economics. That is to say, there is no third system that functions both economically and politically. A third system would cause the two systems to “stick together” and lose their autonomy. The “division of labor” between the systems would be lost. In the case of integration, if the economy collapsed, the political system would collapse with it–and vice versa.
When a state (which is a collection of organizations operating on a national level) taxes citizens and businesses and spends money, it acts economically; it structurally couples itself with the economy, which means that if something “bad” happens in the economy, something “bad” (from some observer’s perspective) can happen to the state
Systems can be structurally coupled loosely or tightly, and, given the level of taxing and spending, the modern state and the economy are tightly coupled. Tightly coupled systems tend to perturb one another a great deal. For instance, an economic recession can perturb one or many states, prompting new decisions.
A case of loose structurally coupling in modern society would be the coupling between religion and a state. It is unlikely that a change in religious doctrine could significantly destabilize a modern state, and it is unlikely that a political decision made by a modern state could significantly destabilize religion. Which is why the framers of modern constitutional republics took such pains to keep government and religion apart. They didn’t want religious wars that could bring down a nation.
As for psychic systems, consciousness attends to/notices its environment, which can be sensory impressions arising from within the body (e.g., a racing heart, a fever, a stomach ache) or external forces which impinge on the nervous system (i.e., anything seen, heard, felt, smelled, or tasted). And with internalized language, the psychic system can think about these perceptions, and, of course, think about thoughts. In this case, the psychic system internalizes the social medium of language and uses it for its own purposes.
The main point here is that the events and structures of consciousness, like the physical body, are completely excluded from the events and structures of communication. This is what it means to say that autopoietic systems are operationally closed. Consciousness allows communication to happen, but consciousness is excluded from communication; that is to say, consciousness must remain in the environment of the communication system. This is good for consciousness because if communication becomes impossible consciousness doesn’t cease its operations. Consciousness and communication are not integrated, which means they don’t rise and fall together. Helen Keller didn’t lack consciousness before she learned to communicate.
Structural Coupling and Uncoupling
Another way of putting this (if yet another way is needed!) is that structural coupling implies or includes potential 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, statements spoken or written can remain in a communication system as long as they are repeated or recur in further communication. The “original” speakers and listeners (or writers and readers) can be long dead, but the communication can remain in circulation. It’s true that some human consciousness has to be around to keep the language in 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.Introduction to Sysems Theory, 199
So, after all this work, what is gained by excluding everything 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; it only depends on consciousness. Consciousness, in turn, only has to directly depend on the organic systems of the body. This simplifies matters quite a bit. Communication doesn’t have to directly depend on a properly functioning brain or heart because consciousness depends on all that. If these organic preconditions (blood flow, etc.) aren’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.Introduction to Systems Theory, 200-201
The physical body depends on a livable environment—oxygen, food and water, shelter from cold, etc. It structurally couples with the environmental elements. It also depends on gravity to prevent it from floating into outer space. Returning to where this post started, skeletal and muscular systems develop in accord with Earth’s gravity.
The term structural coupling is also used in chemistry. Here an example, which I don’t pretend to understand:
A number of reviews have been published about function, structure, and evolution of PSII extrinsic proteins in various photosynthetic organisms . . . . In this review, we focus on the structural coupling of extrinsic proteins with the oxygen-evolving center (OEC) in different photosynthetic organisms, which has been investigated by reconstitution experiments combined with light-induced Fourier transform infrared (FTIR) difference spectroscopy . . . . This technique can detect the structural changes in the OEC in the S-state transitions, including the changes in the secondary structures of polypeptide main chains, amino acid side chains, and hydrogen bond networks of proteins and water molecules . . . . The results of FTIR are evaluated in light of the current knowledge on the subunit interactions in PSII and also discussed in terms of the changes that occurred during evolution.