Post-post-posting, I found that I am not the first person ever to interpret the stone soup story in a religious context. In fact, it seems to be a relatively common metaphor for social generosity, with the stone being seen as the religious catalyst. Thus I have failed in my duty to make this blog a true content provider; despite my best intentions, it turns out that in this case I have merely regenerated pre-existing content.
That's my first apology.
Though in my defense, for me the stone soup metaphor still does imply that the townsfolk were fooled, or were at least fooling themselves. The story wouldn't be any fun if the guy had used a magic potato - it's crucial that the stone be obviously doing nothing except fooling people into doing what they should have been doing in the first place. Maybe a thoughtful religious person could recognize this aspect but still see it as making a positive point about religion anyway, namely, that due to some quirk of human nature, people only due the right thing when magic is involved. Many atheists, though, would see the same story as revealing an embarrassingly inefficient system, and hope that the townsfolk could be educated not to need the stone at all, like the vagabond character (and atheist hero) .
Hm, I guess it's this ambiguity that makes this metaphor so thought-provoking (albeit apparently only unoriginal thoughts).
My second apology is for searching the web for other people using stone soup metaphors. I can't be doing this with every post, or I'll get discouraged at how unoriginal I am. Who knows, I might even stop posting for a while!
Or maybe - just maybe - this blog is the stone, and the townsfolk are all those other things I've heard or read before, and nobody is really ever totally original, but that's OK because....