Often doctrine specifically suggests a body of religious principles as it is promulgated by a church , but not necessarily : doctrine is also used to refer to a principle of law , in the common law traditions , established through a history of past decisions , such as the doctrine of self-defense , or the principle of fair use , or the more narrowly applicable first-sale doctrine .
But it can also mean a principle of law , in the common law traditions , established through a history of past decisions , such as the doctrine of self-defense , or the principle of fair use .