Presumption of culpable mental state shifts burden to accused to prove absence of mens rea with strict proof standard. The court shall presume the existence of the required culpable mental state in prosecutions under the Act, but the accused may raise a defence by proving absence of that mental state. 'Culpable mental state' includes intention, motive, knowledge and belief. A fact is considered proved only when believed beyond reasonable doubt, creating a rebuttable presumption of mens rea subject to a strict proof standard.