The persona designata doctrine is a doctrine in law, particularly in Canadian and Australian constitutional law which states that, although it is generally impermissible for a federal judge to exercise non-judicial power, it is permissible for a judge to do so if the power has been conferred on the judge personally, as opposed to powers having been conferred on the court. The doctrine in the more general sense has been recognised throughout the common law countries (including the United States). "Persona designata", according to "Black's Law Dictionary", means "A person considered as an individual rather than as a member of a class"; thus it may be a person specifically named or identified in a lawsuit, as opposed to the one belonging to an identified category or group. While it has its origin in Montesquieu's doctrine of the separation of powers, it can be traced back as far as Aristotle's "Politics".