"You cannot prove a negative" Answered
It's commonly held that negative statements cannot be proven. The absence of something cannot be proven, and absence of evidence is not proof of absence.
For example, some people claim that NASA did not land men on the moon. NASA can offer proof that they did, which may be disputed, but it cannot be proven that they did not.
However, the statement "You cannot prove a negative" is also negative, and if it holds true it cannot be proven either.
Point: Taking this position doesn't amount to very much.