I answer that, Harm may bear a threefold relation to sin. Because sometimes the harm resulting from a sin is foreseen and intended, as when a man does something with a mind to harm another, e.g. a murderer or a thief. In this case the quantity of harm aggravates the sin directly, because then the harm is the direct object of the sin. Sometimes the harm is foreseen, but not intended; for instance, when a man takes a short cut through a field, the result being that he knowingly injures the growing crops, although his intention is not to do this harm, but to commit fornication. In this case again the quantity of the harm done aggravates the sin; indirectly, however, in so far, to wit, as it is owing to his will being strongly inclined to sin, that a man does not forbear from doing, to himself or to another, a harm which he would not wish simply. Sometimes, however, the harm is neither foreseen nor intended: and then if this harm is connected with the sin accidentally, it does not aggravate the sin directly; but, on account of his neglecting to consider the harm that might ensue, a man is deemed punishable for the evil results of his action if it be unlawful. If, on the other hand, the harm follow directly from the sinful act, although it be neither foreseen nor intended, it aggravates the sin directly, because whatever is directly consequent to a sin, belongs, in a manner, to the very species of that sin: for instance, if a man is a notorious fornicator, the result is that many are scandalized; and although such was not his intention, nor was it perhaps foreseen by him, yet it aggravates his sin directly.
But this does not seem to apply to penal harm, which the sinner himself incurs. Such like harm, if accidentally connected with the sinful act, and if neither foreseen nor intended, does not aggravate a sin, nor does it correspond with the gravity of the sin: for instance, if a man in running to slay, slips and hurts his foot. If, on the other hand, this harm is directly consequent to the sinful act, although perhaps it be neither foreseen nor intended, then greater harm does not make greater sin, but, on the contrary, a graver sin calls for the infliction of a greater harm. Thus, an unbeliever who has heard nothing about the pains of hell, would suffer greater pain in hell for a sin of murder than for a sin of theft: but his sin is not aggravated on account of his neither intending nor foreseeing this, as it would be in the case of a believer, who, seemingly, sins more grievously in the very fact that he despises a greater punishment, that he may satisfy his desire to sin; but the gravity of this harm is caused by the sole gravity of sin.
