oneil's reply to this post brings out a very important idea: promises
are connected to issues about security and preditability. Daoists
would see promises as a way of trying to guarantee something that
cannot be guaranteed. We make promises in the hope that, in making
them, the world will go the way we'd like it to go: promises are a way
of trying to control nature. But sometimes promises should be broken:
for instance, if your friend asks you to hold his weapons for him
until he asks for them, and you make a promise to do that, but then
one night your friend shows up in a drunken rage demanding his guns so
he can shoot some guy he was arguing with at the bar, you should
probably break your promise -- because if you keep it, you're not
being a good friend. I suspect Daoists might think of promises as
what people resort to when they lack trust -- if they would just trust
the flow of nature, they wouldn't try to control that flow with
promises.