Article I. How Much is to be Restored

The quantity of restitution must be measured from the quantity of the thing accepted, or from the quantity of the damage inflicted, or of the influence upon the injury of the neighbor. Since special difficulties occur concerning solidarity alone, we shall treat specially of that alone.

Solidarity, or the obligation of restoring in solidum, is the burden incumbent on individual cooperators of repairing the whole damage inflicted. A twofold kind is distinguished: namely absolute, which has place when someone is held to repairing the whole damage; and conditioned, when individual cooperators are held to restore for other cooperators who fail.

I say 1st. Anyone from the cooperators efficaciously concurring to damage, so that this whole damage can morally be ascribed to him, is held to restitution in solidum, that is, in its entirety, whether absolutely or at least conditionally. The reason is that anyone is the efficacious and unjust cause of the whole damage, and therefore must repair the whole. - And we say that the whole damage certainly can be ascribed to some cooperator in a twofold case, namely: 1st, as often as his cooperation is necessary, although not sufficient for inflicting the whole damage; 2nd, as often as cooperation is made from an efficacious conspiracy, by which the damagers so efficaciously excite themselves to the damage that, if individuals did not concur, the damage would not occur. Cf. St. Alphonsus, n. 579. - Vogler, n. 342.

I say 2nd. Whoever is the principal cause of the damage is held to restore in solidum absolutely; but the rest of the equal cooperators or secondary causes are held only conditionally. The reason is that the principal agent, as the one mandating, the leader, etc., by that fact absolutely takes upon himself the whole burden of repairing the damage, since he primarily inflicts it and does not use others except as instruments for damaging the neighbor.

Question 1. Whether there is an obligation of restoring in solidum, where cooperation indeed exerted influence on the whole damage of an indivisible thing, but of itself is not sufficient nor necessary, nor proceeds from strict conspiracy; for example, if four carry away a beam which three also would have carried away?

Resp. Negatively, because, since the whole reason of the obligation is influence on the damage, that obligation ought not to be greater than the influence itself. Moreover, one who concurred to a part of divisible damage, although with others he concurred to the whole damage insofar as the part contributes to completing the whole, certainly would not be held to restoring the whole; therefore, by parity, he who concurs partially to indivisible damage is held only partially to the reparation of the damage, because he placed a partial cause. Cf. St. Alphonsus, n. 579. - Lugo, disp. 19, n. 83. - Vogler, n. 343.

Question 2. Whether you are held in solidum if your action was indeed sufficient for inflicting the whole damage, but in no way necessary, nor did it proceed from conspiracy; for example, if you applied fire to another's house together with several others?

Resp. Negatively, at least probably, and the reason is that, although the damaging action was sufficient for the whole damage, nevertheless it had only a partial influence upon it, since it was neither necessary nor common with others from conspiracy. Therefore it is not the moral cause of the whole damage. Nor does it matter that it is a question of an indivisible thing, because the cooperation is not extended to the whole damage. Nevertheless understand this as often as without your concurrence the damage nevertheless would have occurred; otherwise even your action would have to be called necessary to it. - Cf. St. Alphonsus, n. 679; and Hom. Ap., n. 55.

Here one must altogether advert to the warning of St. Alphonsus, namely: in practice it is rarely expedient that the obligation of repairing the whole damage be manifested to the unlearned, although they are certainly held in solidum, provided however that they have damaged only as secondary causes. The reason is that an obligation of this sort cannot easily be persuaded to the unlearned. - Cf. St. Alphonsus, Hom. Ap., n. 54.