An eccentric philosophy professor gave a one
question final exam after a semester dealing
with a broad array of topics. The class was
already seated and ready to go when the
professor picked up his chair, plopped it on
top of his desk and wrote on the board:
"Using everything we have learned this semester,
prove that this chair does not exist."
Fingers flew, erasers erased, notebooks were
filled in furious fashion. Some students wrote over
30 pages in one hour attempting to refute the
existence of the chair. One member of the class
however, was up and finished in less than a minute.
A week later when the grades were posted, the rest
of the group wondered how he could have gotten an
"A" when he had barely written anything at all.
His answer consisted of two words: "What chair?"