Section 1. On the Quantity of Restitution

498. Notions. 1. The quantity of restitution, when several concur in inflicting the same damage, can be different in three ways: for they are bound either in solidum absolutely, or in solidum conditionally, or only pro rata.

2. Solidarity, or the obligation of restoring in solidum, is the burden incumbent on each cooperator of repairing the whole or solid damage which was inflicted by several. Solidarity is called absolute if someone alone must repair the whole damage, while the others are bound only if he is deficient; it is called conditional if someone is bound to repair the whole damage only where others do not restore. If he restores the whole damage, in the first case he cannot demand compensation from the other cooperators; but in the other case he can demand compensation from them by right. The obligation of restoring pro rata is the burden incumbent on each cooperator of restoring only part of the damage inflicted.

499. Principles. In general it must be said that only he who is the cause (whether physical or moral) of the whole damage is bound to restitution in solidum. In particular:

1. He who together with others is the cause (whether physical or moral) of the whole damage, and indeed the principal cause, is bound to restore in solidum absolutely: for because he is the cause of the whole damage, he is bound in solidum, and because he is the principal cause, he must repair it absolutely; for others acted in his name and as his instruments, and therefore are bound to restitution only if he is deficient.

The principal cause is the one mandating with respect to the mandatary, and the one counseling who takes care that the counsel be executed solely in his own favor. Therefore he who by his mandate induces servants to steal, who seeks companions for carrying off a stolen thing, is bound to restitution in solidum absolutely; the cooperators are bound only if he is deficient.

2. He who together with others is the cause (whether moral or physical) of the whole damage, and indeed an equal cause, is bound to restore in solidum conditionally: in solidum indeed because he inflicted the whole damage, but conditionally because he inflicted it not alone but together with others.

It is asked when someone must be held as the efficacious cause of the whole damage.

a. He inflicts the whole damage who by common conspiracy concurs with others for inflicting damage, as if several conspire to despoil a house, because each influences at least morally the whole damage, provided the conspiracy is true and efficacious. But true conspiracy is had when each determines the others by persuasion, exhortation, etc., to inflict damage.

b. He inflicts the whole damage whose cooperation, whether moral or physical, is necessary for inflicting the damage, so that if he did not concur the damage would not be done, as if two despoil a traveler whom one could not despoil, or if someone casts a vote necessary for an unjust sentence which the others, if he were absent or contradicting, would never have given. For although his cooperation does not suffice for inflicting the whole damage, nevertheless, if the cooperation were denied, it could have impeded the whole damage. If someone helps a thief to carry off a chest which neither could carry alone, each is bound to repair the whole damage, because each is the cause of the whole effect insofar as without his help there would have been no effect.¹

c. He inflicts the whole damage who is the moral cause per se sufficient of the whole damage, as if two give counsel for inflicting damage which each so influences the whole damage that even one would have sufficed for inflicting the same, or that even without the other the damage would have been inflicted: for it cannot be denied that several moral causes can be total or adequate causes of the same effect.²

3. He who together with others is the cause (whether moral or physical) of partial damage is bound to restore pro rata of the influence on the damage, as if several without mutual conspiracy concur to despoil a tree or to ravage a crop.

a. A partial cause of damage is he whose action is neither sufficient nor necessary for producing the whole effect, so that even without that action the effect would have happened, although it made it easier; as if four carry away another's beam which even three could have carried away; if three ravage a field which even two would have ravaged; or if someone suggests to a thief determined to steal a motive for stealing which indeed moves him but by itself alone could not have moved him. Therefore in this case each is bound to restore pro rata of cooperation.

b. They dispute whether he whose physical action is indeed sufficient for producing the whole effect, but not necessary, so that even without it the effect would have happened, is a partial or total cause of the damage, because it is not sufficiently established whether even several physical causes can be total and adequate causes of the same effect. Since the opinion affirming him to be only a partial cause is truly probable, in this case the obligation of restoring in solidum is not to be established, but only pro rata. Therefore if two without mutual conspiracy take away a chest filled with things which one could have taken away and would truly have taken away if the other had been absent; if two at the same time discharge into another's goat and kill it, which even one would have killed, each is bound only to part of the damage.

There are some who distinguish whether several together place an action sufficient of itself for the effect, as if two together discharge into another's goat and kill it, or whether they do not together place an action sufficient of itself for the effect, as if someone on another side applies fire to a house to which another has already applied fire. But this distinction does not seem necessary, since in each case the damaging action is a partial cause, from which no obligation arises except of restoring part of the damage.

4. What is to be done in doubt is resolved from the principles of probabilism. Therefore:

a. In doubt whether someone influenced the whole damage, he is not bound to restore in solidum, because the obligation of restoring in solidum is not certainly established.

b. In doubt whether others have restored their part, likewise he is not bound to repair the whole damage if it is truly probable that others have already restored or will restore: for the obligation of restoring the part of others is doubtful.

For practice St. Alphonsus wisely warns: "It must be noted that the rude, even if they are bound in solidum, it is rarely expedient to oblige them to the whole, since with difficulty they persuade themselves that they are bound to restore the part taken away by companions. Indeed, it can be sufficiently presumed that the owners themselves, to whom restitution is owed, consent that they restore only the part taken away by them, since otherwise there is great fear that they will restore nothing if they are obligated to the whole."³

¹ Cf. Ballerini-Palmieri III, n. 376.

² Cf. Ballerini-Palmieri III, n. 380 and 388.

³ St. Alphonsus, n. 579.