Tenn. R. Evid. 601
Every person is presumed competent to be a witness except as otherwise provided in these rules or by statute.
Tenn. R. Evid. 601
Advisory Commission Comments.
This language is similar to T.C.A. § 24-1-101 [repealed], first sentence. Virtually all witnesses may be permitted to testify: children, mentally incompetent persons, convicted felons. Rules 602 and 603 should be read in connection with this rule, however, because any witness must swear or affirm to tell the truth and must have personal knowledge of that truth. The common law rebuttably presumed children under fourteen incompetent, Ball v. State, 188 Tenn. 255, 219 S.W.2d 166 (1949), but the proposed rule is contra. See also T.C.A. § 24-1-101 [repealed], second sentence, making children under age thirteen competent in sexual offense prosecutions.
The most important statute referenced by the rule is the Dead Man Statute, T.C.A. § 24-1-203. It applies generally to prevent parties from testifying to transactions with a deceased person in actions by or against estates. While the statute occasionally causes proof problems, the rule leaves it intact. See also T.C.A. § 24-1-202 [repealed] on incompetents' estates.
Advisory Commission Comments [1992].
The amendment removes the earlier language requiring "of sufficient capacity to understand the obligation of an oath or affirmation"and establishes a rebuttable presumption of competency. Note, however, that Rule 602 requires lay witnesses to have personal knowledge of matters, and Rule 603 requires all witnesses to swear or affirm they will tell the truth.