Consider the Nut Room
Suppose you love pistachio nuts, and are given a room
filed with them to a level of five feet. But you must
eat them in the room, and must leave the shells.
When will you have eaten all the nuts?
Never.
As it becomes increasingly difficult
to find nuts amid the shells, the nuts will
not be free anymore. When the cost—in time
and effort—of the nuts becomes too high,
a substitute will be preferred—nuts
from a store, or another snack.
—George Will 4/1/01