Why the Irish, and Indians, rationally believe in fairies

"Because the upside to disbelief is too small."

Zigackly. I picked this gem up from Michael Lewis' hilarious new book, Boomerang. The passage in question is about Ireland:

Ian (Michael Lewis' Irish guide) will say “Over there, that’s a pretty typical fairy ring,” and then explain, interestingly, that these circles of stones or mushrooms that occur in Irish fields are believed by local farmers to house mythical creatures. “Irish people actually believe in fairies?,” I ask, straining but failing to catch a glimpse of the typical fairy ring to which Ian has just pointed. “I mean, if you walked right up and asked him to his face, ‘Do you believe in fairies?’ most guys will deny it,” he replies. “But if you ask him to dig out the fairy ring on his property, he won’t do it. To my way of thinking, that’s believing.” And it is. It’s a tactical belief, a belief that exists because the upside to disbelief is too small...

To my ears, that rings true of India too. Superstition is about economic, rather than scientific, rationality. Lewis' chapter about Ireland is still visible at Vanity Fair.