Sometimes it is not possible to lay down the law by reason of a single water Pur grilled rely on history came to describe the legal provisions in order to better understand the intent of the law, in the law.
Sometimes the law is not a rational one wants to rely on history to explain the origin of the legal provisions in order to understand the intent of the legislation.
Sometimes the enactment law also does not adhere to the principle of pure reason alone relies on history to explain the origins of legal provisions to understand the intent of the act, legislation.