Obj. 3: Further, every special sin is constituted by something which specifies the moral act. But the notion of scandal consists in its being something done in the presence of others: and the fact of a sin being committed openly, though it is an aggravating circumstance, does not seem to constitute the species of a sin. Therefore scandal is not a special sin.
On the contrary, A special virtue has a special sin opposed to it. But scandal is opposed to a special virtue, viz. charity. For it is written (Rom. 14:15): "If, because of thy meat, thy brother be grieved, thou walkest not now according to charity." Therefore scandal is a special sin.
I answer that, As stated above (A. 2), scandal is twofold, active and passive. Passive scandal cannot be a special sin, because through another's word or deed a man may fall into any kind of sin: and the fact that a man takes occasion to sin from another's word or deed, does not constitute a special kind of sin, because it does not imply a special deformity in opposition to a special virtue.
On the other hand, active scandal may be understood in two ways, directly and accidentally. The scandal is accidental when it is beside the agent's intention, as when a man does not intend, by his inordinate deed or word, to occasion another's spiritual downfall, but merely to satisfy his own will. In such a case even active scandal is not a special sin, because a species is not constituted by that which is accidental.
Active scandal is direct when a man intends, by his inordinate word or deed, to draw another into sin, and then it becomes a special kind of sin on account of the intention of a special kind of end, because moral actions take their species from their end, as stated above (I-II, Q. 1, A. 3; Q. 18, AA. 4, 6). Hence, just as theft and murder are special kinds of sin, on account of their denoting the intention of doing a special injury to one's neighbor: so too, scandal is a special kind of sin, because thereby a man intends a special harm to his neighbor, and it is directly opposed to fraternal correction, whereby a man intends the removal of a special kind of harm.
Reply Obj. 1: Any sin may be the matter of active scandal, but it may derive the formal aspect of a special sin from the end intended, as stated above.
Reply Obj. 2: Active scandal can be found separate from other sins, as when a man scandalizes his neighbor by a deed which is not a sin in itself, but has an appearance of evil.
Reply Obj. 3: Scandal does not derive the species of a special sin from the circumstance in question, but from the intention of the end, as stated above. _______________________
FOURTH ARTICLE [II-II, Q. 43, Art. 4]
Whether Scandal Is a Mortal Sin?