(1) In any prosecution for an offence under this Act which requires a culpable mental state 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.-- In this section "culpable mental state" includes intention motive, knowledge of a fact and belief in, or reason to believe, a fact.
     (2) For the purpose of this section , a fact is said to be proved only when the court believes it to exist beyond a reasonable doubt and not merely when its existence is established by a preponderance of probability.