(b) In the persons who commit the sins there may be circumstances that change the order of guilt, so that he who commits the greater sin is less guilty. Examples: By his careless handling of a revolver, Balbus unintentionally causes lasting injury to a bystander. Caius without malice aforethought, but enraged by an unexpected insult, strikes a blow that destroys the sight in one eye of his adversary. Titus, angry because he has been dismissed from his employment, revenges himself by defacing a precious work of art. The bodily injuries caused by the first two men are more harmful than the injury to property done by Titus; but they sinned, the one from ignorance and the other from passion, whereas Titus sinned from malice. Hence, while the sins of Balbus and Caius are objectively or materially greater, that of Titus is greater subjectively or formally (i.e., as to guilt). 230. The Subjects of Sin.--By the subjects of sin we understand the powers of the soul in which sin is found. These powers are sometimes called the material causes of sin, just as the objects to which the sins tend are called their formal causes. 231. Just as virtuous habits have their seats in the will (e.g., justice), in the reason (e.g., prudence), and in the sensitive appetites (e.g., fortitude and temperance), so also contrary habits of vice may be found in these same faculties. (a) From the sensitive appetites proceed impulses caused by sense apprehension or bodily states, which, when they are inordinate and voluntary, are sinful (e.g., lust, envy; see 129, on Second Motions). (b) From the reason proceed false judgments caused by vincible ignorance, wrong direction deliberately given to the passions, pleasurable dwelling on inordinate thoughts, etc. (c) From the will proceed consent given to sins of the other powers, desires to commit sin, joy over sin already committed, etc. 232. As was said above (89-93), the external acts of the members of the body have no morality of their own, since they are completely subject to the will. Consequently, there are only three classes of sins, if classification is made according to the faculties from which the sins proceed: (a) sins of sensuality, which were spoken of above when we treated of the passions (177 sqq.); (b) sins of thought; (c) sins of desire and reminiscent approval. 233. Pleasurable dwelling on inordinate thoughts occurs when one deliberately, even though it be only for a moment, turns over in his mind some sinful object, delighting in it as if it were actually present, but not desiring that it be actually done. Example; One who imagines his neighbor’s house burned down, and rejoices at the mental picture, though for interested reasons he does not wish any conflagration in the vicinity. 234. The sinful thoughts just described are not to be confused with thoughts in which the object of the delight is something else than a sinful picture represented in the mind.