By David Leonhardt, New York Times
magine that a bunch of children are sitting around a table when a seemingly beneficent adult walks into the room carrying a plate of cupcakes. The kids burst out in excitement — until they notice a problem: There are fewer cupcakes than children.
At this point, the adult announces some ground rules. To receive a cupcake, the children will have to compete with one another. The adult will accept cash or other objects of value. Praise for the adult’s kindness would also be welcome.