The more effectively the environment of a system is protected by more encompassing systems from too intense, unpredictable fluctuations, the more effectively the system can move over to directing its actions by internally rationalized decision-making techniques, and replace trust with calculations of probability. Whether, and under what conditions, such a process of substitution is itself rational can likewise only be judged within the framework of our comprehensive idea of rationality, whereby trust, which has apparently come about 'irrationally', may appear rational if and in so far as it performs the functions which serve the maintenance of the system.

DEFINE: Clarifies how trust functions as a substitute for rational calculation within systems protected from environmental fluctuations.

Niklas Luhmann, Trust and Power, loc. 318