Common-Source Doctrine Law and Legal Definition
Common-source doctrine is a legal principle requiring a defendant in a trespass to try title action who claims under a source that is common to both the plaintiff and the defendant. Common-source doctrine is an attribute of the law of trespass to try title. Thus, the common-source doctrine does not prevent a defendant from showing that s/he or a third party has a better title than the plaintiff under the common source. [Kennedy v. Whaley, 55 N.C. App. 321 (N.C. Ct. App. 1982)].
However, under common-source doctrine, a defendant is not obliged to demonstrate title in a third source that is paramount to the common source. Because doing so amounts to an attack on the source under which the defendant claims title.