In any prosecution for an offence under this Act which requires a culpable mental state on the part of the accused, the court shall presume the existence of such mental state but it shall be a defence for the accused to prove the fact that he had no such mental state with respect to the act charged as an offence in that prosecution.
        Explanation.--For the purposes of this section,--
                 (i) the expression "culpable mental state" includes intention, motive, knowledge of a fact, and belief in, or reason to believe, a fact;
                 (ii) a fact is said to be proved only when the court believes it to exist beyond reasonable doubt and not merely when its existence is established by a preponderance of probability.