2. Incompetency is material, ratione materia, or personal, ratione personae. The first takes place when a judge takes cognizance of a matter over which another judge has the sole jurisdiction, and this cannot be cured by the appearance or agreement of the parties.
3. The second is, when the matter in dispute is within the jurisdiction of the judge, but the parties in the case are not; in which case they make the judge competent, unless they make their objection before they. take defence. See Peck, 374; 17 John. 13; 12 Conn. 88; 3 Cowen, Rep. 724; 1 Penn. 195; 4 Yeates, 446. When a party has a privilege which exempts him from the jurisdiction, he may waive the privilege. 4 McCord, 79; Wright, 484; 4 Mass. 593; Pet. C. C. R. 489; 5 Cranch, 288; 1 Pet. R. 449; 4 W. C. C. R. 84; 8 Wheat. 699; Merl. R«p. mot Incompet«nce.
4. It is a maxim in the common law, aliquis non debet esse judex in propriŠ causa. Co. Litt. 141, a; see 14 Vin. Abr. 573; 4 Com. Dig. 6. The greatest delicacy, is constantly observed on the part of judges, so that they never act when there could be the possibility of doubt whether they could be free from bias, and even a distant degree of relationship has induced a judge to decline interfering. 1 Knapp's Rep. 376. The slightest degree of pecuniary interest is considered as an insuperable objection. But at common law, interest forms the only ground for challenging a judge. It is not a ground of challenge that he has given his opinion before. 4 Bin. 349; 2 Bin. 454. See 4 Mod. 226; Comb. 218; Hard. 44; Hob. 87; 2 Binn. R. 454; 13 Mass. R. 340; 5 Mass. R. 92; 6 Pick. 109; Peck, R. 374; Coxe, Rep. 190; 3 Ham. R. 289; 17 John. Rep. 133; 12 Conn. R. 88; 1 Penning R. 185; 4 Yeates, R. 466; 3 Cowen, R. 725; Salk. 396; Bac. Ab. Courts, B; and the articles Competency; Credibility; Interest; Judge; Witness.
INCOMPETENCY, evidence. The want of legal fitness, or ability in a witness to be heard as such on the trial of a cause.
2. The objections to the competency (q. v.) of a witness are four-fold. The first ground is the want of understanding; a second is defect of religious principles; a third arises from the conviction of certain crimes, or infamy of character; the fourth is on account of interest. (q. v.) 1 Phil. Ev. 15.