Question XVII: Whether an oath given through fraud, error, or ignorance is void

I SUPPOSE, that mere Ignorance means the privation of knowledge, or the positive assertion of a false thing, which is called error; but Dolus means an injurious deception of the one demanding the oath.

DUPLEX, however, is dolus, or ignorance, and error; one antecedent, namely that which induces to the doing of the act, and provides the very cause of it, which the Jurists call giving cause to the contract leg. et eleganter, ff. de dolo, namely because, if that dolus or error were not present, the contract would not follow; the other, truly, accompanies the act, namely that which does not induce to willing the act, but so accompanies the act that even if it were not present, still the act would follow: and this is called by the Jurists Incidens in contractum, seu contingens, in distinction from the former, which is called ex proposito.

I ASSERT first, that dolus, or error, or antecedent ignorance renders an oath void. It is the common opinion with St. Bonaventure in 4. dist. 30. quaest. 1. who note that it must concern the substance of the thing.

It is proved by St. Bonaventure there, because there is no consent of one in error leg. si per errorem, ff. de iurisdict. omnium iudic. leg. cum testamentum et leg. Non idcirco, Cod. de iuris, et facti ignorantia. Therefore void is the marriage entered into with Bertha, who was believed to be Thecla. Sanchez reports an example. If anyone swear to give to someone a thing which he takes to be glass, and afterward find it to be a gem: and St. Bonaventure, if anyone, thinking to buy gold, and declaring that he wants gold, should receive aurichalcum; for if he did not declare himself, the contract would bind, because a purchase is a contract founded on the external; but in a contract which requires internal consent concerning the thing, it would not suffice, as in marriage.

I ASSERT second, that probably it is not the case that concomitant error renders it invalid, if such an intention be present: I would wish, even if it were that one.

It is proved, because consent does not fail from knowledge. See Sanchez lib. 7. de matrimonio, disp. 18. where many are for this opinion against Sanchez himself. Observe, there, whether it be St. Bonaventure.

I ASSERT third, that error concerning qualities only does not render an oath invalid.

It is proved, because here it does not take away consent.

Against the first assertion seems to be that which the Saintly Doctor says, that Joshua was deceived by the Gabaonites into making a league, whom he shows to have judged himself bound, from St. Ambrose lib. de officiis.

The Saintly Doctor answers there in 3. dist. 29. quaest. ultima, ad 1. that Joshua judged it better to spare them, not because he was bound in the sight of God, but lest he excite scandal. Therefore St. Ambrose says that Joshua judged that the peace he had given was not to be recalled, because it had been confirmed by the religion of the Sacrament, lest, while he reproved another's perfidy, he dissolve his own faith. This therefore he preserved, believing that it did not displease God to receive penitents, although He had commanded that they not join leagues with those obstinate ones.