Can someone give me proof that black magic, sorcery, and possession does NOT exist?

It is pretty much impossible to prove a negative. In a court case, a defense lawyer does not need to prove that his client did not commit the murder for which he was accused. The defense lawyer only needs to create doubt in the minds of the jury. If the prosecuting attorney cannot prove beyond reasonable doubt that the crime was committed by the accused, then the jury must find him innocent.