We can use an old concept and qualify this peculiar advance with normative consequences we have been talking about as a supererogatory performance. One may call supererogatory a performance which does not flow from some previously assumed duty but manifests itself as meritorious, and attracts respect. In spite of recent attempts, the relationship between such a performance and duty remains logically and analytically obscure. However, what is of interest to us here is purely its function in the genesis of trust. It entails somehow an excess on the normative which has some parallels with the excess on the information discussed previously; it constitutes a surplus performance, which nobody can require, but which (for the self-same reason) engenders claims – as benefactions for instance engender a claim to gratitude.

Niklas Luhmann, Trust and Power, loc. 198