The precise origins of the Three Living and the Three Dead are still somewhat mysterious, but there are many versions of the tale dating back to the 13th century, with the best-known coming from England and France. The basic version of the story goes like this: three young noblemen are out hunting when they suddenly come across three corpses, which are in varying states of decay, but nonetheless still animated. Unsurprisingly, the young men express shock and dismay at the sight, while the three corpses admonish them to consider the transience of life and to improve their behaviour before it is too late.
A couple of observations are in order here. First, although io9 characterizes this as a “zombie” story, these are not your usual mindless zombies. They appear capable of deep thought and reflection, and they also seem to lack any hunger for human flesh (unless those Medieval storytellers buried the lead in a serious way). Although zombies and vampires are the most commonly discussed varieties of undead (thus their representation in the subtitle of Economics of the Undead), any player of Dungeons & Dragons knows there are also liches, revenants, ghosts, mummies, ghouls, and many more. Perhaps “The Three Living and the Three Dead” deals with one of these other types.
Second, it’s interesting that the undead would impart a lesson about the transience of life, as their very existence proves that a person may continue to exist in some form even after death. Apparently we are to believe that, despite their ability to think and their lack of hunger, these undead creatures have a terrible existence — perhaps a punishment by God for their sins. That would also explain why an awareness of life’s transience shouldn’t motivate you to gather ye rosebuds why ye may, but instead to adopt a less sinful lifestyle.
What lessons might be drawn by someone who doesn’t share a Medieval Christian perspective? If becoming undead is seen as a threat — an awful future that is effectively the end of one’s “true” life — then becoming aware of its possibility would presumably make you place more value on the present (in economist lingo, increase your discount rate). But if becoming undead is seen as a gift — as in many recent depictions of vampires, especially in the YA literature — then knowing about it would tend to make you place more value on the future (decrease your discount rate), in large part because it means your future could be a lot longer than previously expected.
For more on the impact of immortality on the rate of discount, see Fabien Medvecky’s chapter, “Sinking Our Teeth into Public Policy Economics: A Taste of Immortality,” in Economics of the Undead.