§ II. On Those Things which Can Vitiate Consent

Three things can vitiate the consent of some contracting party, namely error, deceit, and fear. Concerning fear, what it is and of how many kinds it is has been said in n. 16. But error and deceit differ in this, that the former is deception proceeding from ignorance, and the latter from artful frauds; for deceit, viewed in itself, is a contrivance employed for deceiving another.

I say, 1st. Every deception, whether it proceeds from ignorance or from deceit, renders a contract null if it affects either the substance of the thing, for example, if you buy copper for gold, or the nature of the contract, for example, if you take leasing for sale; but not if it affects only an accidental quality of the thing, at least if without the deception the contract nevertheless would have been entered into. The reason for the first is that then the consent would be only external but not internal; and the reason for the second, that deception concerning accidents does not destroy the efficacy and substantial force of consent. Nevertheless, except if the quality is expressly intended as a condition without which not, because then it passes into the substance of the thing.

Error renders an act void if it turns upon that which constitutes the substance of the act or falls into a condition without which not; otherwise the act is valid, unless something else is provided by law; but in contracts error can give place to a rescissory action according to the norm of law (Can. 104).

I say, 2nd. No contract from fear from within, or from a necessary or natural cause, is invalid or rescindable, unless perhaps he who contracts from fear was not master of himself. The reason is that no injury is inflicted on the contracting party, and moreover he preserves sufficient liberty. The same must be said if fear from a free cause has been inflicted for a just cause. The reason is that not only is such a contract voluntary simply, but also the danger in which the contracting party is placed is voluntary to him in its cause, nor can he complain of it as of an injury. Indeed even grave fear inflicted unjustly by a free cause does not impede of itself that the contract be voluntary simply, and therefore valid. Therefore by reason only of the injury which fear contains, it can sometimes harm the value, or at least the firmness, of the contract.

You Will Resolve. - 1st. If a priest at night buys cloth for himself, thinking it is of black color, while it is green or violet, the contract is not valid if he expressly declared that he wished cloth of black color; for although color in itself is a mere quality, in this case it passes into the substance, and therefore the error becomes substantial.

2nd. If, when you wish to buy Bordeaux wine, California wine is offered, the contract is valid in itself, notwithstanding error or deceit, because the error is not substantial. But justice is injured accidentally if the Bordeaux is more expensive; and therefore the seller will be liable to restitution. But if the price of each wine is equal, or if the price is diminished according to the proportion of the excess, the seller will be immune from injustice, although not from the sin of lying. - I said in itself, because the error could easily be substantial, as, for example, if the buyer had bound his intention by express words to Bordeaux wine on account of a certain end to which any other would not conduce.

3rd. He who buys from a bookseller a book which he judges good and afterwards discovers to be bad, nevertheless has contracted validly, because he wished to buy this present book absolutely and without restriction, although certainly he would not have bought it if he had known it to be bad. But otherwise, if a false title of the book had been inscribed, because then the title would have furnished the cause of substantial error.

4th. Unjust but light fear is not considered, unless it gives cause to the contract; but then, if it is a question of a gratuitous contract, it more probably invalidates it; but if of an onerous contract, more probably it neither invalidates it nor makes it rescindable.

5th. § 1. If someone, moved by grave fear unjustly inflicted, or circumvented by deceit, has placed an act or entered into a contract which is not null by the law itself, he will be able, once fear or deceit has been proved, to obtain rescission of the act or contract by an action which is called rescissory (Can. 1684). Cf. St. Alphonsus, nn. 716 and 717; and Hom. Ap. n. 125. - Lugo, disp. 22, nn. 115 and following. - Reuter, nn. 126 and 127.

6th. Error falling upon the final motive invalidates. If, for example, a book to be bought by me is proposed to me because it rightly explains the truths of faith, vindicates her rights to the Church, and does not spread prejudices against her, and I, wishing to have such a book precisely because of those reasons authoritatively proposed to me, buy it; but afterwards I find that the book contains great prejudices against the Church, certain things also scandalous, false, blasphemous; certainly I am not held by such a contract, for it is null - for we contracting parties did not consent to the same thing.

Question. Does error or deceit concerning a quality indeed, but which nevertheless gives cause to the contract, invalidate this contract?

Resp. Affirmatively, more probably, if it is a question of a gratuitous contract, because such a contract from its nature requires a full voluntary and every kind of spontaneity. But negatively if it is a question of onerous contracts; thus Can. 103, §2: Acts placed . . . by deceit are valid unless something else is provided by law, but they can be rescinded by sentence of the judge. - Cf. St. Alphonsus, nn. 714 and 715; and Hom. Ap. nn. 124 and 125. - Lugo, disp. 12, n. 84.