The term double contingency (or social contingency), originally from the theory of the famous American sociologist Talcott Parsons, describes the fact that both ego and alter [→Meaning Dimensions] reciprocally observe their selections as contingent.
In logic, contingency means the exclusion of both necessity and impossibility. The term contingency determines a datum in reference to the possible alternatives: it describes the situation in which what is current (i.e., not impossible) could also be different (i.e., not necessary). Therefore, contingency describes the possibility that a datum is different than it is. A datum is contingent when it is observed as a selection from an area of background possibilities: the datum derives from a selection that determines its non-being as the being of other possibilities.
The selectivity of →meaning-constituting systems is always contingent, i.e., the operations [→Operation/Observation] of these systems are not clearly determined in advance. Contingency is the fundamental problem for the coordination of selectivity in social and psychic systems, since possibilities for communication and thought are indeed only possibilities: they may be realized differently than expected [→Expectations]. Thus, contingency means the potential for disappointment and the necessity of risk-taking. In the social dimension, this problem appears as double contingency: every selection is dependent on both ego and alter, and both are meaning-constituting systems.
For every ego, alter is an alter ego whose behavior is unpredictable and capable of variation. Both ego and alter determine their own behavior self-referentially within their own boundaries [→Self-Reference]. Each is a black box for the other, because their selection criteria cannot be observed from the outside. The only thing visible to ego is the selectivity resulting from alter’s operational closure: everyone observes everyone else as a system in an environment, and can observe only the input and output from and to the environment and not the self-referential operations themselves. Every system shows the others the indeterminacy of its own self-reference, along with the determinacy of its own selections.
Due to these conditions, double contingency does not mean single contingency twice, but rather a specific social quality of contingency: it means that the construction of the social world comes about through a doubled perspective horizon (the perspectives of ego and alter). Ego can observe a datum from the perspective of the possibilities actualized by alter, thereby becoming also ego’s possibilities. Ego cannot experience alter’s experiences, but can observe alter’s perspectives and adopt them as her own as necessary. Thus, with these restrictions, alter’s world is made available to ego (and vice versa): the world becomes socially contingent. Both ego and alter experience double contingency; they each include in their own perspectives the perspectives of the other and must then take them into account.
Both partners observe double contingency and the resultant indeterminacy of behavior. This leads to the emergence of a tautological circularity dependent on neither ego nor alter, in which ego constantly refers to alter and vice versa, according to the general pattern: “I’ll do what you want, if you do what I want.”
This circularity is interrupted by a new systemic order and becomes asymmetrical [→Asymmetrization]. The new order originates from the reciprocal observation of ego and alter, and from the information this observation creates. This new order is an operationally closed social system that autopoietically reproduces through the coordination of alter’s and ego’s contingent selections. Double contingency is thus the foundation for the autocatalysis of social systems.
Double contingency constantly dissolves because its emergence triggers a process that leads to the solution to [sic! ; of] the problem (Problemlösung). In its “pure” form, therefore, double contingency does not exist; it is a constant problem that is included in social systems as a fundamental part of their own reproduction.
A social system emerges because there is no certainty in a situation of double contingency. Social systems control the uncertainty by structuring communication possibilities based on the indeterminacy of ego’s selectivity for alter and alter’s selectivity for ego. The structures of expectations fulfill the function of managing uncertainty, ensuring the potential for coordinating selections, and structuring social systems. [C.B.] – Unlocking Luhmann, p 75–77.
Social Systems (1995: Ch. 3); Generalized Media and the Problem of Contingency (1976); The Differentiation of Advances in Knowledge (1984).