The minimum requirement for an efficient outcome is that the bear be able to incur an enforcible promise and that he be able to transmit credible evidence that he is committed, either by a penalty incurred or by a maneuver that destroys his power not to comply (like extracting his own teeth and claws).

DEFINE: Defines the two-part requirement for credible commitment: an enforceable promise plus credible evidence of the commitment through penalty or destroying one's own ability to defect.

Thomas C. Schelling, The Strategy of Conflict, loc. 345