As the discussion opens, John highlights just how important promises are.  Civilization, he says, heavily depends on people keeping their promises to people they don’t particularly like, in cases where it isn’t to their direct advantage to do so.  Why can we trust in the word of another when we'd otherwise either regard him as unpredictable, or bound to act in his own interest?  And why does he oftentimes feel guilty for not complying?  Where does that guilt come from?  How, Ken asks, does the act of saying something create an obligation that wasn’t there before?

Neil thinks that it arises naturally out of our basic propensity to cooperate with, and trust and depend on others.  Our convention of promising is a formalized way of the more basic act of fostering reliance.  He invites us to imagine a man trapped on a low beach, bordered by cliff-faces, during a rising tide.  And we are to imagine a second man, a stranger, casting a rope down to him from one of the cliffs.  If the man with the rope lets it go while the victim is halfway up the cliff-face, then walks away, he has done wrong.  To intentionally create a reliance, and then to intentionally disappoint it, is a breech of our natural morality.

John points out that Neil's theory that we have an instinctual concept of "proto-promising," constitutes an answer to Hobbes' state of nature. Such an instinct would show that we have a natural tendency towards cooperation, not just competition.  What follows is an inquiry into the finer points of promising, and the audience contributes questions motivated by personal experience.  What makes some promises legally enforceable and some not?  Neil says that if the promise is intended to establish a legal relation, then its enforceable.  What is the difference between a promise and a vow?  What do we do about conflicting obligations and promises?  And what about political promises?  How compelling must the circumstances be to override a promise, be it to cut taxes, to wed for life, or to go to your child's baseball game?

Ken brings an Existentialist perspective to the discussion.  It seems that to bind yourself to a promise, even when you're so different from when you made the promise that no longer feel like the same person, is to surrender your will.  Neil tells us this is a perfectly fine position, but points out that we're responsible for the promises we make.  And if someone thinks that promises imprison us, and that that's a very bad thing, they shouldn't promise in the first place, and if they want to foster a reliance they ought to do so in other terms.

• Roving Philosophical Report (seek to 6:12): Polly Stryker turns our attention to romantic promises, and promises within marriage.  Marital promises are interesting because they blur the line between legal contracts and our personal obligations to loved ones.  She talks to a divorce attorney to explore the dynamics of such promises.

• 60-Second Philosospher (seek to 48:47): Ian Shoales delves into another one of his internet-inspired explications, this time of our concepts of promises and promising.  The world, at least, as represented by Google searches, is rife with disappointment.