Section 2. An Efficacious Cause of Damage

456. In order that a damaging action induce the obligation of restitution, it is required that the damage have actually followed from the action as from its own cause: for he alone can be obligated to repair damage who is author of the damage and therefore either himself effects the damage or in some way moves another to effect the damage.

Therefore the obligation of repairing damage is not had: a. if the damaging action is only the occasion of the damage: for an occasion is not a true cause, but that at whose presence the true cause acts; b. if it is only a condition without which not, or that without which the cause cannot act; c. if it is only a cause per accidens, from which damage can indeed follow, but it is not probable that it will follow from it, and therefore that it will follow is not foreseen: for justice does not oblige one to avoid actions from which damages to another follow only remotely and per accidens.

a. If a theft committed by Titius, from error because of other thefts previously perpetrated by Sempronius, is imputed to Sempronius, who therefore is punished as guilty of theft, the theft of Titius is the occasion of the damage which Sempronius suffers; its cause is the judge's sentence arising from the judge's error.

b. If someone returns a sword to him who abuses the sword to commit homicide, the handing over of the sword is a condition without which the homicide would not have been committed.

c. A cause per se of an effect is said to be that which by its nature is ordered to producing it; thus applying fire to a barn is the cause per se of the burning of the barn. A cause per accidens of an effect is said to be that which by its nature is not ordered to producing this effect, but produces the effect only when external circumstances concur; thus to kindle fire in a remote place, which a wind unexpectedly arising casts into the barn, is the cause per accidens of the burning of the barn. Therefore a cause per accidens: alpha. contributes something to producing the effect, whereas the occasion and necessary condition contribute nothing; beta. its connection with the effect is neither certain nor probable, but only possible, and therefore the effect is not foreseen by the agent.

457. Resolutions. 1. He who by his example entices others to inflict damage is not bound to repair the damage inflicted by them, even if he foresaw, indeed even if by acting he intended, that others would follow his example: for example is not a cause, but a mere occasion of the action of others, who imitate the example. And indeed not the example which they see, but the evil will of the others, is the cause of the damaging action, which itself is the efficacious cause of the damage. Yet he who truly induces others to inflict damage is bound to repair it: for induction is not a mere occasion, but the cause of the action of others.

2. If someone's damaging action is imputed to another, for example, if someone's theft is imputed to another, who suffers damage from it, one must distinguish.

a. If he either did not foresee the damage, or indeed foresaw it and even intended it, but did not use means by which suspicion of the crime would be turned onto the other, he is not bound to repair it, because he is not the cause, but the occasion of the damage: for the cause of the damage is the error or evil will of those who ascribe the damaging action to the innocent person, and he by his action offers an occasion to this error. b. But if he not only foresaw the damage, but if in addition he used means which would supply a grave motive for attributing the action to another, for example, if to steal he dressed himself in another's garments, or if to commit homicide he used another's weapons and threw the weapons sprinkled with blood into his house, he is bound to repair the damage, because he is its cause per se.

To the question whether a guilty man is bound to denounce himself, lest an innocent man be punished as guilty, one must answer thus. In the former case he is not bound to denounce himself as guilty, because, since he is not the cause of the damage, he is bound only from charity to free another from penalty; but charity does not oblige with so great an inconvenience. In the latter case he is bound to denounce himself, because, since he is the cause of the damage, he is bound from justice to free another from penalty; but justice obliges the guilty man even with equal damage to himself.

3. If someone's damaging action of itself is only a cause per accidens of damage, but is placed by the agent with the single and direct intention that the damage follow, this intention brings it about that the effect is voluntary and can be imputed to the agent as a cause per se, provided his action truly existed as the cause of the damage and was placed uniquely, or at least primarily, from this intention. But if the action does not truly cause the damage, it must be called its occasion; and if it is placed from another intention, it is the cause of the damage per accidens.

He who steals from a miser a thing of slight value and by this theft is the cause why the miser falls into a grave illness is the cause of the illness per accidens; but if he intends only this, that the miser fall into illness because of that taking away, he is the cause per se of the illness and must repair his damage, because he is at the same time the unjust cause of the damage. He who places a snare in a road through which his enemy rarely passes, yet with the intention that the enemy, going to pass by chance, break his leg, is the cause per se of the damage and is bound to reparation, because at the same time he acts unjustly. But if from another end he places the snare while at the same time desiring the enemy's damage, he sins internally against charity, and the external action is the cause of the damage per accidens, although unjust.¹

¹ Cf. Lugo, disp. 8, n. 75.