(d) As regards the evil consequences of acts, foreseen or natural, one is responsible for the evil, if one could and should have prevented it. Examples: Titus knows that a beggar will use profane language if denied an alms, but Titus cannot spare the money and is not responsible for what happens. Sempronius blasphemes in the company of many, and is therefore guilty of the sin of scandal, since he has no right to blaspheme; (e) As regards the evil consequences of acts that could not have been foreseen, they are not imputable. Example: Balbus steals fifty cents from Caius, and the latter is so heartbroken that he commits suicide. Balbus is not responsible for the suicide, since such a thing was far from his thoughts when he stole. 103. It was just said (102, d) that when two results, one good and one evil, follow an act, the evil is imputable if it could and should have been prevented. It is not always easy, however, to determine at once when the evil result should be prevented, and, as cases of double effect are many, it will be useful to give rules that are more particularized, and that enable one to decide when it is lawful to do that from which will follow an act indirectly willed, or a consequence that is evil. 104. It is lawful to perform an action from which an evil effect is foreseen when the following conditions are present: (a) the action willed itself must be good or at least indifferent; for clearly, if the action is bad, it is also unlawful; (b) a good effect must also follow from the act, and it must not be caused by the evil effect; for the end does not justify the means. Thus, it is not lawful to take what belongs to others in order to give alms, for the evil effect (stealing) results from the act (taking) immediately; whereas the good effect (almsgiving) results only mediately through the theft; (c) the agent must intend only the good effect, since it is unlawful to wish evil. Thus, if one foresees that one’s virtuous life will cause the sin of envy in a neighbor, this evil result of one’s virtue must not be entertained by one as something pleasing; (d) the agent must have a reason sufficiently weighty for permitting the evil result that follows his act. Evil should not even be permitted, unless there is adequate compensation in the good that is intended. 105. To judge whether a reason for permitting an evil effect is proportionately grave, the following rules should be kept in mind: (a) the greater the evil that results, the greater must be the good that is intended. Thus, it is not lawful to kill a robber in order to save a small amount of money: but it is lawful to kill an aggressor, if this is necessary in order to save one’s life;