Impossible

... when you have eliminated the impossible, whatever remains, however improbable, must be the truth.
Sherlock Holmes
Truth (11), Impossible (2)Sir Arthur Conan Doyle (1)

The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair.
from his book "Mostly Harmless"
Difference (1), Thing (1), Possible (1), Impossible (2)Douglas Adams (3)