Whoever trusts has to keep control over his own preparedness to accept the risks involved. He must make it clear to himself, if only to reassure himself, that he is not trusting unconditionally but rather within limits and in proportion to specific, rational expectations. It is himself he must curb and control when he puts his trust in someone or something. This is an intrinsic part of the structure of motives which trust makes possible, and comes about by making the object of trust more attainable with the help of symbols of trustworthiness.

Niklas Luhmann, Trust and Power, loc. 161