Stability, instability, balance, imbalance, structure, etc., are mechanistic metaphors that don’t fit social theory very well. For instance, structural instability is a bad quality in a bridge or tall building, but it’s necessary for autopoiesis to happen. Structural instability is a quality of any dynamic, evolving, or “living” thing.
The problem is that equilibrium is associated with stable systems. For instance, a gymnast on a balanced beam achieves a sense of stability, even though the stability can be easily disturbed. But imbalanced systems or structures can also be stable. As Luhmann writes,
If one uses the term “disturbance,” one must be clear about the fact that one is no longer dealing with a theory of equilibrium. Theories of equilibrium or balance had also included the concept of disturbance. In fact, the entire model had been formulated in two directions in terms of disturbances. On the one hand, there was the easiness or probability of disturbance. If you think of scales, it takes very little force, just a few added grams to one side, to disturb the balance. [These ideas] emerged in the seventeenth century and concerned the artificiality of the balance of trade or the international balance of power. But on the other hand, one always imagined that the equilibrium has a sort of infrastructure or apparatus at its disposal that serves its self-maintenance. As a consequence, a disturbance leads to the reconstitution of the equilibrium. . . . In principle, however, the meaning of this model, which, to be sure, is really a metaphor, was to earmark equilibrium as a stable system. Or . . . one might say that, in such a model, the maintenance of the system structure is tied to the concept of equilibrium.
Today this linkage has become questionable in several respects. On the one hand, in natural science the prevalent idea is that it is precisely imbalance which can be stable, and in economics a system is said to be stable if either too many goods are on offer and there are too few buyers or, vice versa, if there are too many buyers and not enough goods. . . . This tendency puts the old model in doubt. If, on the other hand, one proceeds from ideas of autopoiesis, operational closure, and structural coupling, the balance model becomes questionable simply because one would have to regard imbalances and balances as functional equivalents, since both serve to maintain stability. . . . Now, the question is how a disturbance can be conceptualized internally within the system if one does without the equilibrium model. (Intro to ST p. 89)(Introduction to Systems Theory, p. 88-89)
If the scales weren’t easily tipped to one side or the other, the device would be useless/dysfunctional. The following bullet points come from Investopedia:
- Economic equilibrium is a condition where market forces are balanced, a concept borrowed from physical sciences, where observable physical forces can balance each other.
- The incentives faced by buyers and sellers in a market, communicated through current prices and quantities drive them to offer higher or lower prices and quantities that move the economy toward equilibrium.
- Economic equilibrium is a theoretical construct only. The market never actually reaches equilibrium, though it is constantly moving toward equilibrium.
The third point, that markets never actually reach equilibrium, is important.
Equilibrium is a concept borrowed from the physical sciences, by economists who conceive of economic processes as analogous to physical phenomena such as velocity, friction, heat, or fluid pressure. When physical forces are balanced in a system, no further change occurs. For example, consider a balloon. To inflate a balloon, you blow air into it, increasing the air pressure in the balloon by forcing air in. The air pressure in the balloon rises above the air pressure outside the balloon; the pressures are not balanced. As a result the balloon expands, lowering the internal pressure until it equals the air pressure outside. Once the balloon expands enough so that the air pressure inside and out have are in balance it stops expanding; it has reached equilibrium.
Equilibrium is a fundamentally theoretical construct that may never actually occur in an economy, because the conditions underlying supply and demand are often dynamic and uncertain. The state of all relevant economic variables changes constantly.https://www.investopedia.com/terms/e/economic-equilibrium.asp
In social systems theory, structures are expectations. They are all about time, not space or material structure. So we are not talking about blowing up balloons. Structural coupling, then, means the coupling of expectations.
Structural instability, in a social sense as well as a linguistic sense, is generative. For example, the metaphor of the body, as in the body politic or a social body, is generative because bodies can be distinguished as male and female. In a study or Venetian politics, Sperling wrote
The body metaphor enabled Contarini to conceive of a structural identity between the patriciate and the whole of society — two different bodies, of which the former represents the interests and tensions of the latter and balances them out. The miracle of Venice was precisely to have established a set of governmental institutions that not only defused the tensions within the political class of patricians, but that did so metaphorically for the rest of the city. A miracle indeed (of rhetorical virtuosity, one should say). Although employed to denote the stability, unity, and homogeneity of the signified concept, the body metaphor derives its rhetorical power from its structural instability and its capacity to generate (other metaphors). First of all, bodies can be differentiated in two versions: male and female — as is the case in Venetian mythology and its iconographic representation. The connection between Venice, the republic, and Venice, the city, is conceived as a gendered relationship between the masculine body politic (composed of male aristocrats over age 25) and the feminine body of the city.Sperling, J. G. (1995). Convents and the body politic in late renaissance venice (1550-1650).)
We must distinguish between random instability and structured instability. Autopoietic systems have structured instability, which supports a particular system function. Function takes precedence over structure. This is true for physical structures and social structures. If the function of a bridge is to allow people to cross a river, the structure is subordinate to that function. If the function of an organization is to communicate decisions, the structure is again subordinate to that function. Structures that become dysfunctional must be abandoned. In this view, Luhmann breaks with Parsons’ functional structuralism.