devil's proof; probatio diabolica
Legal term for the difficulty of proving a negative, especially in defamation or property cases where one must prove something does not exist.
The devil's proof is considered extremely difficult to establish under the law.
In this case, the defendant is being asked to provide a devil's proof.
From Latin 'probatio diabolica', a legal concept referring to the impossibility of proving a negative. The Japanese term is a direct translation.