Article First. On the Nature of Contracts

523. Notions. The most frequent mode of acquiring ownership is contracts, in which a great part of social life is contained (n. 382).

The terms pact, contract, stipulation, which in Roman law are distinguished, are now usually used without distinction.

1. Contract can be defined: the consent of two or more persons concerning a right to be transferred.

a. A contract in fieri must be distinguished, which consists in mutual consent by which one transfers some right and another accepts it, and a contract in facto esse, which is the effect arising from mutual consent. That effect is the acquisition and possession of the right transferred and accepted, with which coheres the obligation, arising from the transfer of right, of doing or omitting something. Now the definition adduced sets forth the contract in fieri.

b. Therefore the immediate effect of any contract is commutation of right, from which arises an obligation of doing or omitting something; and according to the diversity of the contract this obligation arises either from each side or at least from one side.

c. The contract itself and its obligation depend especially on the free will of those contracting, so that without the will of the contracting parties no contract subsists, and beyond their will it does not oblige.

2. For entering a contract validly, four conditions are essentially required: a. apt matter; b. capable persons; c. mutual consent; d. cause of the consent. Each of these must be discussed. Yet the essence of contract consists in mutual consent concerning some right, so that the contract remains imperfect as to essence as long as each contracting party has not given consent.

3. In every contract three things must be distinguished: essentials, naturals, and accidentals.

a. Essentials of a contract are called those things without which a certain contract cannot be substantially perfected, as the consent of the contracting parties and merchandise and money in sale: for without consent there would be no contract, and without merchandise and price there would be no sale.

b. Naturals of a contract are called those things which, either from law or from custom, are considered to be contained in a contract unless they are excluded by the express will of the contracting parties, as in sale the security of the buyer in the case of eviction.

c. Accidentals of a contract are called those things which are considered excluded from a contract unless by express agreement of the contracting parties they are received into it, as payment in a determined money or delay of payment beyond the time established by law.

¹ John de Lugo, De iustitia et iure, tom. II, De contractibus. Lucius Molina, De iustitia et iure, tom. II, De contractibus. L. Lessius, De iustitia et iure, l. 2, c. 17-28. Jos. Carriere, De contractibus, 3 tom. (Paris: Mequignon, 1839). Jos. Schwane, Die theol. Lehre uber die Vertrage^2 (Munster: Theissing, 1872). A. Vermeersch, Quaestiones de iustitia^2 (Bruges: Beyaert, 1904), q. 7-10. Add the authors who wrote the whole of moral theology, cited above p. 382.

524. Divisions of contracts. 1. By reason of effect: a. Unilateral, which produce an obligation in only one of the contracting parties, as promise and donation; and bilateral, which produce an obligation in each contracting party, as purchase-sale, lease-hire, loan for consumption, and loan for use.

b. Nude, which generate only a natural obligation or obligation of conscience; clothed, which produce a natural and civil obligation, or one in the external forum.

Nude contracts rest on the consent alone of the contracting parties; these the external forum does not acknowledge nor furnish aid for their execution. Clothed contracts have, besides the consent of the contracting parties, other solemnities prescribed by law joined to them, for example, writing, and therefore are acknowledged in the civil forum and produce a civil action. Contracts which do not produce a civil action (nicht klagbare Vertrage) are different according to the diversity of civil codes.

c. Gratuitous, in which only one of the contracting parties assumes a burden and the other has only an advantage, as in donation, loan for use, deposit; onerous, in which each contracting party has a burden and advantage, as in sale and lease, in which each receives something and must return something.

2. By reason of mode: a. Consensual contracts, which are essentially perfected by consent alone, as in some laws sale; and real contracts, which are finally essentially perfected by handing over of the thing, as loan for consumption and pledge.

There are contracts whose very nature and name demand the real handing over of the object, as loan for consumption, loan for use, deposit; but some contracts require for their essence, besides mutual consent externally manifested, nothing else, as sale, lease, etc. In these contracts, the real handing over of the matter pertains by natural law not to the essence but to their execution and complement.

b. Solemn contracts, which are made with certain formalities prescribed in law; simple contracts, which are contracted without formalities from the sole conditions of natural law.

From natural law no formalities are required in celebrating contracts, so that without them they are valid; but by positive law, for some contracts, determined formalities or solemnities are prescribed, without which they do not have force in civil law. Thus for testaments and hypothec certain legal forms are prescribed.

c. Contracts formally initiated, which are made by words or signs expressly showing consent; virtually initiated contracts or quasi-contracts, which are made by the tacit consent of the contracting parties. Thus he to whom the office of judge or pastor is conferred, by accepting the office tacitly obligates himself to undergoing all the obligations of that office; therefore undertaking an office is a quasi-contract.

But to jurists a quasi-contract is a presumed contract, to which one of the contracting parties indeed does not consent, because he is ignorant of the contract, but to which he would consent if he knew it. Thus he who usefully conducts the business of an absent person deservedly presumes that the absent person consents to the management of the business. Indeed it cannot be denied that contracts are valid, especially exchanges, from the presumed will of the other contracting party, provided this can reasonably be presumed; which obtains if the exchange does not harm the other but profits him.

3. Contracts of certain event, in which something must be given or done independently of a fortuitous event, as in donation and lease; aleatory contracts (Glucksvertrage), in which something must be given or done only dependently on a fortuitous event, as in gaming, wagering, insurance.

4. Named contracts, which have a proper name in law, as sale, lease, etc.; and unnamed contracts, which lack a proper name and therefore are signified only by the generic name of contract. Unnamed contracts are recalled to four species: a. I give that you may give; b. I give that you may do; c. I do that you may do; d. I do that you may give. It must be noted that by the verb to do, not to do is also signified, for example, I give you money so that you do not accuse me.

5. Principal and accessory contracts, according as they subsist in themselves and independently of another agreement, as sale, or depend on another agreement or suppose it, as hypothec.

6. Pure contracts, to which no mode or no condition is added; and qualified contracts, to which a mode or condition is added. Wherefore qualified contracts are subdivided into modified contracts, to which a mode is added, and conditioned contracts, to which a condition is added.

There are other divisions of contracts, which nevertheless either do not occur in recent codes, as contracts of good faith and of strict right, or are understood of themselves from the terms themselves, as valid, firm, void, and rescindable contracts.