Presumption of culpable mental state: accused may rebut by proving lack of intention, motive or knowledge beyond reasonable doubt. Section 278E establishes a rebuttable statutory presumption that a required culpable mental state-including intention, motive, knowledge, belief or reason to believe-exists in prosecutions under the Income-tax Act; the accused may defend by proving absence of that mental state. It further provides that a fact is proved only when the court believes it exists beyond reasonable doubt rather than by a preponderance of probability.