If one accepts that a distinction between media-code and the subject area of communication can be achieved, one comes to the question of whether and how the code can steer the change of subject area. Differentiating between the two levels of meaning is only justified if the code does not lay down concretely what should be ordered. The code, like language itself, also remains abstract in the sense that it does not establish a sequence according to which communication about a subject area is to take place. On the other hand, it cannot be completely indifferent to the boundaries placed around possible subjects. It defines the conditions for possible subjects which can be dealt with under this particular code, and the question is to what extent such 'conditions of possibility' at the same time take on a regulating function, giving a rough direction to the communication process.

Niklas Luhmann, Trust and Power, loc. 652