In A Systems Theory of Religion, Luhmann argues that inclusion rules are now delegated to function systems. For instance, the individual person is included in the economy and the legal system by having access to money and legal protections. Without money, the person cannot participate in the economy; so for the sake of survival, people do whatever they have to to obtain money. But individuals are not compelled to take part in any function system. As Luhman puts it,
One can practically not exist without money, and even less without legal protections. And everyone, unless fully unsuited, is sent to school . . . Sick people have to be cared for [at least in some countries] . . . But no one is compelled to take part in art, nor really in politics (except passively via the mass media). . . . Nor does one have to take part in religion. . . .
In addition to this issue, there are also interdependencies between inclusions. . . . Whoever does not have an identity card cannot get a job. And whoever has to live on the street cannot register his children for school (as I was told in Bombay). Without schooling, one barely has a chance of practicing a reputable career, or obtaining a better job. Without income, one barely has access to healthy nourishment, and no energy for regular work. Illiterates, for instance, barely have the opportunity to exercise their right to vote. To be sure, no one is fundamentally excluded from function systems . . . . Yet the aforementioned negative interdependencies completely exclude individuals (more or less effectively) from participation in all function systems. In fact, a large part of the population is excluded, as can be observed in the Third World and U.S. slums. . . .
Each deficit reinforces another one; the circulation of disadvantages continues and is inescapable (unless, admittedly, one is in the Mafia). . . .
Classical theory of societal integration (such as Durkheim’s) must be turned on it head. Strong integration is always negative integration and for that reason ominous. Positive integration can only be established loosely. (A Systems Theory of Religion, 218-19)
Negative integration is stronger than positive integration. In other words, if I am excluded from the education system, I will inevitably be excluded from other function systems. However, the reverse is not necessarily true: It doesn’t follow that obtaining an education (being included in the education system) naturally leads to inclusion in the economy or politics. Nor does receiving healthcare (being included in the healthcare system) lead to automatic inclusions in other function systems. Nor does being included within a religion mean I will get a decent job. These inclusions are not tightly linked, whereas illiteracy is strongly linked with poverty.
Inclusion in several of the function systems involves a personal decision, such as whether or not to vote or run for political office, join a religion, produce or appreciate art, engage in scientific research, see a doctor or dentist, participate in sports, go to graduate school, etc. But the ideal of liberal democracy is that these things will be available to everyone regardless of social class, race, gender, disability, etc. On the other hand, parents are compelled to provide basic education for their children, either in schools or at home. And we are compelled to follow laws, or risk loss of freedom.
As for the reference to turning classical theory on its head, Durkheim theorized that societies are held together, or integrated, through shared norms, beliefs, and values (collective consciousness). This consciousness is promoted by social institutions. According to the Stanford Encyclopedia of Philosophy,
Typically, contemporary sociologists use the term [social institutions] to refer to complex social forms that reproduce themselves such as governments, the family, human languages, universities, hospitals, business corporations, and legal systems. A typical definition is that proffered by Jonathan Turner (Turner 1997: 6): “a complex of positions, roles, norms and values lodged in particular types of social structures and organising relatively stable patterns of human activity with respect to fundamental problems in producing life-sustaining resources, in reproducing individuals, and in sustaining viable societal structures within a given environment.”
But Luhmann turns this on its head by arguing that the negative societal integration (exclusion) is stronger than positive integration, or inclusion through shared norms, beliefs, values, and social institutions. The Stanford source also states,
Social institutions need to be distinguished from less complex social forms such as conventions, rules, social norms, roles and rituals. The latter are among the constitutive elements of institutions.
Social institutions also need to be distinguished from more complex and more complete social entities, such as societies or cultures, of which any given institution is typically a constitutive element.
Durkheim and Parsons, among others, argued that strong social institutions are necessary for preventing moral decay.
But for Luhmann, society is held together not by shared norms, beliefs, values, and social institutions, but rather by double contingency. Communication, or society, is the solution to the problem of double contingency.