1889. Cessation of Obligation.—The obligation of a contract ceases in various ways: (a) by action of the contractants, as when a promisee renounces his right, or each of the parties to a promise has made a gratuitous promise in favor of the other and one refuses to keep his word; (b) by action of law, for example, by prescription, by annulment; (c) by impossibility, as when a thing freely promised has become unlawful or useless, or when the donee of a gift _mortis causae_ dies before the donor.
1890. Theft.—Theft is the secret taking of what belongs to another, with the intention of appropriating it to oneself, against the reasonable wishes of the owner.
(a) It is a taking, that is, a carrying away of goods. But theft also includes the receiving or keeping of property, since the harm done is the same as when the goods are carried away. Hence, he who does not restore borrowed or deposited or found objects, or who does not pay back a loan, when he could and should, is a thief.
(b) It is a secret taking, that is, the property is taken away without the knowledge of the owner or lawful possessor, even though he be present. In this respect theft differs from robbery.
(c) It is the taking of property. This includes not only corporeal things (e.g., books, money, jewelry, clothing), but also incorporeal things (e.g., patents, trademarks, copyrights), and even persons if they are looked on as possessions. Hence, plagiarism or infringement of copyright or man-stealing or kidnapping (i.e., the carrying off of another’s slave or child) are forms of theft.
(d) It is the taking of property that belongs to another, that is, of goods of which another person is the owner, or lawful possessor as usufructuary, guardian, depositary, etc. Hence, one can steal from oneself by taking one’s goods by stealth from the bailee with the design of charging him for their value or of depriving him of their use to which he has a right.
(e) It is the taking away of goods with the intention of appropriating them to one’s own possession, use or enjoyment to the exclusion of the rightful owner. Hence, strictly speaking, it is not theft to carry away property with the intention of borrowing it for a time or of destroying it; but these are acts of unlawful possession or of unlawful damage. It is obligatory to take an object from another, if this is necessary to prevent the commission of a crime (e.g., to take away and hide the gun with which another intends to kill).
(f) It is against the wishes of the owner. This refers to the substance (that is, the conversion of the property to one’s use), not to the mode (that is, secrecy with which it is done). Hence, if the owner is unwilling that the property be taken, he who takes it is guilty of theft; if the owner is not unwilling that it be taken, but is unwilling that it be taken without his knowledge, he who takes it in this way sins at least venially, but is not guilty of theft in the strict sense.
(g) It is against the reasonable wishes of the owner or possessor; for no injury is done if he does or should consent to the loss. The owner does consent if the person who takes the goods is acting according to a general and recognized custom (e.g., when a servant takes things left over from her employer’s table, which it is certain the latter does not wish to keep); the owner should consent, if justice forbids that he prevent the taking (e.g., when a starving man is taking food from one who has plenty), or if domestic duty commands that he should give the thing taken (e.g., when a wife takes from her husband’s pockets the needed money he denies his family, for a wife and family have the right to receive from the head of the house support according to their station and means). But the owner is not bound to consent to the loss of his goods from the mere fact that he misuses them to his own spiritual disadvantage, or owes them in charity to the taker. Hence, it is theft to take a flask from the pocket of one who drinks too much, or to steal a book from one who is harmed by reading it, or to filch money from a rich man because one is poor and he will not give an alms.
1891. Unauthorized Use of Another’s Funds.—What is the guilt of one who uses for his own purposes the money of another entrusted to him for other purposes?