Communicating about a medium’s code requires another medium, reducing autonomy.

Evidence

In the end, it is held, power has to be legitimized, and in this context legitimacy is defined by means of value consensus. A satisfactory explanation of what is meant by this has not, however, been reached. One possible way of making it more precise would lie in the idea that communications about the code of a medium must always be directed through another medium. For systems theory, this would mean that [symbolic generalized] media systems lose their autonomy in respect of their most important symbols and are thereby most sensitive to the environment. — Niklas Luhmann, Trust and Power, 691