Rezumat
In using the functional method in comparative law, one frequently stumbles on the Common Law notion of promissory estoppel as an equivalent in contracts to the good faith principle of continental civil law. Others "translate" promissory estoppel as an expression of the duty of coherence, which is seen either as a consequence of good faith in contracts or as an autonomous concept with a more objective meaning than traditional good faith. The deeper meanings and rationality of these concepts might have a common thread, but a cynic could say that promissory estoppel is a pragmatic tool for solving a problem unique to the Common Law system: enforcing promises without consideration.