The major contents of this article include the nature, principles, effects and finally probative value of assuming knowledge of law. The basis of legislating this presumption as a conclusive legal one (and not a fiction) is the public policy in preventing irregularity and confusion. It is justified by ‘inwardness state of knowledge and that it is mental’ that makes it difficult to be proved. Although it is considered to be unfair to blame someone who is ignorant of law ,in ‘fiqh‘ sources, every reasonable person is presumed as being aware of law, according to the appearance, unless under certain conditions. This presumption is rebutted in three cases, due to its nature and its probative value according to the Islamic Penal Code: I-when a perpetrator is ignorant of non-criminal provisions such as civil regulations or administrative provisions which are efficient for a crime to come into existence. In these cases, mental element (mens rea) doesn’t exist. II- When the perpetrator’s ignorance is based on own his failure (not his fault). III- In “had (penance)” crimes and in “tazir” crimes (in the strict sense of the term) which are pre-ordained in fiqh; as soon as the accused claims that he was ignorant of law, when it is probable.
