Article — Noldin, Summa of Moral Theology
Article First. On Wagering
619. Nature. Wagering is a contract by which two or more persons disputing concerning the truth of a thing or concerning some event agree between themselves that some good belong to him who wins.
a. Therefore wagering by its nature supposes disagreement among the contracting parties concerning some truth, and a price is constituted for him who is going to attain the truth.
b. Wagering can be a unilateral or bilateral contract. If the first, it obliges either from fidelity or from justice, according as the one wagering intended to obligate himself; if the second, it obliges from justice, provided it has been entered seriously. In this last case those wagering mutually hand over to each other a right to the reward founded on hope of gaining.
c. From the nature of the contract it follows that he who wagers, or plays, without intention of obligating himself to paying contracts invalidly and therefore is not bound to pay, but neither can he accept and retain gain; but he who wagers, or plays, without intention of paying contracts validly and therefore is obligated to paying and can retain gain.
620. Wagering is a just contract: a. If on each side the reward which is wagered is equal, unless the other of his own accord wagers an unequal good of greater value;
b. If the thing is uncertain to each party, even if objectively in itself it is most certain.
Authors dispute whether he who is certain about a future event can enter a just wager. It seems that a distinction must be made thus: a. If someone manifests that he knows the thing certainly, and the other nevertheless wishes to wager, the wager is just. Yet in this case there is not an onerous but a gratuitous wager, by which the other promises that he will give something if the certain event has followed. beta. But if one knowing the thing certainly pretends that he at least in some way doubts about it, the wager is unjust: for the due equality among the contracting parties is lacking, since he who knows the thing certainly hands over to the other a hope of gain which is of no value, since he knows certainly that he is going to be the winner.1
1 Cf. Lugo, disp. 31, n. 78.
621. Wagering is a licit contract: a. If it is made concerning an honorable or at least indifferent thing; therefore illicit is a wager made, for example, concerning the fact that the other lacks courage to commit a duel: for it contains an incitement to dueling. Yet since the wager is just, when the duel has been committed, the thing promised by the wager can be retained as in a contract concerning a base thing, but it need not be furnished (n. 527).
b. If there is present a motive making the wager honorable. An end of this kind is honest recreation, an incentive for completing something or investigating truth. Yet since wagers, the same holds for games, often lack an honest end, and rather are made from vanity or prodigality or desire of becoming rich, and give occasion to innumerable abuses and frauds, in practice they are for the most part illicit.
c. If the good promised by the wager is not excessive: for in this case on one side there is committed a sin of prodigality, with which other sins are generally joined, whether against charity or against piety; and on the other side a sin of induction or at least of cooperation toward evil.1
1 From C.A. Section 1277 wagers do not produce a civil obligation; therefore the victor cannot require by civil action the good owed to him from wagering.