Presumption of culpable mental state shifts evidentiary burden but allows defence to prove lack of mens rea. The court shall presume the existence of a culpable mental state in prosecutions under the Act requiring such an element, but it is a defence for the accused to prove absence of that mental state regarding the charged act; the term includes intention, motive, knowledge, and belief or reason to believe, and a fact is proved only when the court believes it exists beyond reasonable doubt.