Cervantes, in Don Quixote, part two, chapter LI, tells of a law-case that Sancho Panza was called on to decide. A certain town had a bridge. It was the law that any man who crosses the bridge must state where he is bound and why. If the statement were judged true, then the man is set free; but if it judged false, then he is hanged. How savage!
One day a suicidal anarchist crossed the bridge and declared that he was there to be hanged. This created a legal quandary. If he is hanged then he should have been set free, by the law; but if he is set free, then the law declares that he should have been hanged.
Sancho Panza, faithful squire to the Knight of the Woeful Countenance, was given this case to adjudicate. He realized that he would be wrong either way, so he instructed that the man be set free. In so doing he followed the instructions of his master Don Quixote, for the mad knight gave Sancho Panza this rule: when justice is in doubt, then he is to lean to the side of mercy. Sancho Panza said, “I thank God that I happened to recollect it just now, for it fits this case as if made for it.”