Finally, as to whether respondent’s assent to the initial partition agreement serves as an admission against interest, in that the respondent is deemed to have admitted the existence of co-ownership between him and petitioner, we rule in the negative.
An admission is any statement of fact made by a party against his interest or unfavorable to the conclusion for which he contends or is inconsistent with the facts alleged by him. Admission against interest is governed by Section 26 of Rule 130 of the Rules of Court, which provides:
Sec. 26. Admissions of a party. – The act, declaration or omission of a party as to a relevant fact may be given in evidence against him.
To be admissible, an admission must (a) involve matters of fact, and not of law; (b) be categorical and definite; (c) be knowingly and voluntarily made; and (d) be adverse to the admitter’s interests, otherwise it would be self-serving and inadmissible.