Opinion rule (evidence)

General rule. — The opinion of witness is NOT admissible, except as indicated in the following sections.

Opinion of expert witness. — The opinion of a witness on a matter requiring special knowledge, skill, experience or training which he has been shown to posses, may be received in evidence.

Opinion of ordinary witnesses. — The opinion of a witness for which proper basis is given, may be received in evidence regarding —

(a) the identity of a person about whom he has adequate knowledge;
(b) A handwriting with which he has sufficient familiarity; and
(c) The mental sanity of a person with whom he is sufficiently acquainted.

The witness may also testify on his impressions of the emotion, behavior, condition or appearance of a person. (Section 48, Section 49 and Section 50 of Rule 130 of the Rules of Court)