Differences in fundamental values or norms, or lack of consensus, do not necessarily prevent communication, which means lack of consensus does not block the emergence of social systems.
In the chapter 3 of Social Systems, the chapter on Double Contingency, Luhmann writes
Nothing forces us to seek the solution for the problem of double contingency exclusively in an already existing consensus, thus in the social dimension. There are functional equivalents–for example, those in the temporal dimension. At first alter tentatively determines his behavior in a situation that is still unclear. He begins with a friendly glance, a gesture, a gift–and waits to see whether and how ego receives the proposed definition of the situation. In light of this beginning, every subsequent step is an action with a contingency-reducing, determining, effect–be it positive or negative. . . . We can connect this to the “order from noise principle” of general systems theory. No preordained value consensus is needed. The problem of double contingency (i.e., empty, closed, indeterminable self-reference) draws in chance straightaway, creates sensitivity to chance, and when no value consensus exists, one can thereby invent it. The system emerges etsi no daretur Deus [even if God doesn’t exist].Social Systems, 104-05
Here Luhmann revises Parsons’ concept of double contingency. No value consensus is needed for a social system to form. In the above example, he is talking about an interaction system. A person (alter) encounters a stranger (ego) and makes some move: a friendly glance, a gesture, a gift. If ego responds in a positive way–some way that encourages further communication–then alter can go further into the communication system, or establish a social interaction. There is no need to first ascertain either person’s values, their sense of right and wrong, etc.
Luhmann’s example resembles a borderland or contact zone, as when different, operationally closed societies meet for the first time. In this kind of situation, the past (cultural heritage, norms, shared values) doesn’t matter. The interaction is all about expectations for the future–for continued communication. Alter wants to know if ego will reciprocate in some way. In the beginning the possibilities are wide open; this corresponds to noise on the noise-order spectrum. Ego could walk away, refusing to establish an interaction system, or she could strike alter, shout at him, etc. But after the first positive response, alter starts to expect more communication. Thus the horizon of possible responses narrows.
This means that social order does not depend on shared values or cultural norms. Social order (some kind of social system) is established through expectations, in other words, a question–What’s next? This is the temporal dimension referred to above.
The social dimension is a dimension of meaning that “concerns what one at any time accepts as like oneself, as ‘alter ego’ (Social Systems 80). Luhmann speaks of two other meaning dimensions: the temporal and the factual.
The temporal dimension is constituted by the fact that the difference before and after, which can be immediately experienced in all events, is referred to specific horizons, namely, is extended into the past and the future. Time’s bond to what can immediately be experienced is thereby dissolved, and time gradually also sheds its relation to a difference between presence and absence. It becomes an independent dimension, ordered only according to the when and not to the who/what/where/how of experience and action.Social Systems, 77-78
In the social dimension, there is an opposition (or possible oscillation) between twin horizons–consensus and dissent.
Only when dissent can emerge as a reality or a possibility has one occasion to interject the two-fold horizon of the social as the dimension of orientation that is especially important at the moment. . . . The social dimension, once available, enables a constantly accompanying comparison with what others can or would experience and how others could position their actions. . . . [The] social dimension tends to boil down to morality. . . . Morality indicates the conditions under which persons can praise of blame one another and themselves. . .
For societies that are becoming increasingly complex, a global programming of the social dimension in the form of morality becomes increasingly inadequate. . . . [All] morality finally finds itself relativized within horizons where one can ask further why someone experiences , judges, and acts in the way he does, how this occurs, and what that means for others.Social Systems, 81-83
The fact dimension is [. . .] constituted in that meaning divides the reference structure of what is meant into “this” and “something else.”Social Systems, 76
[A] difference is contained in every experience of meaning, namely, the difference between between what is actually given and what can possibly result from it. This basic difference, which is automatically reproduced in every experience of meaning, gives experience informational value. [. . .].
Thus one begins not with identity but with difference. [. . .] We will indicate this discovery with the concept of meaning dimensions and will distinguish the fact dimension, the temporal dimension, and the social dimension. Each of these dimensions acquires its actuality from the difference between two horizons; thus each is a difference differentiated against other differences.Social Systems, 74-75