What is presumption? When is it needed and not needed for interpretation?

The expression "presumption" in interpretation would mean that while interpreting a statute or any provision thereof; the courts must deem certain things to be true and correct. In other words, the court must proceed to interpret with the conception of correctness of certain things. Presumptions are guidelines used by the courts in process of interpretation. However, they are only used if there are any ambiguities in language but sometimes even if there are no ambiguities it can be used by the judges. Where the meaning of the statute is clear, there is no need for presumptions. But if the intention of the legislature is not clear, there are number of presumptions. These are: That the words in a statute are used precisely and not loosely. That vested rights, i.e., rights which a person possessed at the time the statute was passed, are not taken away without express words, or necessary implication or without compensation. That "mens rea", i.e., guilty mind is required for a criminal act. There is a very strong presumption that a statute creating a criminal offence does not intend to attach liability without a guilty intent. That the state is not affected by a statute unless it is expressly mentioned as being so affected. That a statute is not intended to be inconsistent with the principles of International Law. Although the judges cannot declare a statute void as being repugnant to International Law, yet if two possible alternatives present themselves, the judges will choose that which is not at variance with it. That the legislature knows the state of the law. That the legislature does not make any alteration in the existing law unless by express enactment. That the legislature knows the practice of the executive and the judiciary. Legislature confers powers necessary to carry out duties imposed by it. That the legislature does not make mistake. The Court will not even alter an obvious one, unless it be to correct faulty language where the intention is clear. The law compels no man to do that which is futile or fruitless. Legal fictions may be said to be statements or suppositions which are known, to be untrue, but which are not allowed to be denied in order that some difficulty may be overcome, and substantial justice secured. It is a well settled rule of interpretation that in construing the scope of a legal fiction, it would be proper and even necessary to assume all those facts on which alone the fiction can operate. Where powers and duties are inter-connected and it is not possible to separate one from the other in such a way that powers may be delegated while duties are retained and vice versa, the delegation of powers takes with it the duties. The doctrine of natural justice is really a doctrine for the interpretation of statutes, under which the Court will presume that the legislature while granting a drastic power must intend that it should be fairly exercised.