Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 6, a. 3; q. 71, a. 5; q. 77, a. 7.

59. Notions. — Man is not only master of his willing and acting, but also of his not acting and not willing, insofar as "by willing and acting he can impede that which is not willing and not acting"¹. Hence:

1° According to the different things which proceed from the will, the voluntary is rightly called positive if the placement of the act proceeds, — negative if the omission of the act proceeds. For a voluntary omission is not to be confused with the will of omitting; for the omission of fornication or of Mass is not voluntary for him who is detained in prison, and yet he can have the will of omitting fornication or Mass, while he says within himself: I would not do it or I would not hear it, if I could; — on the contrary, an omission can be voluntary even if one does not say: I will not hear, provided that, at the time when he can hear Mass, he does something else voluntarily. In the 1st case there is the placement of the act, namely commission, i.e. of desire, which is positively voluntary (I will not act i.e. I will not to act); in the 2nd case omission of the act, and this is negatively voluntary (I do not will to act). Both, however, can exist at once, while from the will of omitting one omits the work.

The positive voluntary essentially includes an act, because it proceeds from the will through a real influx. The negative voluntary does not essentially include an act: for in its essence it is constituted not by an act but by a negation, because it is not an act but the omission of this; this, however, that it may proceed from the will, supposes a preceding or concomitant act of the will as its cause or occasion: for either a man intends the omission itself in itself, or at least he voluntarily places another act incompossible with the omitted act, such as playing, sleeping, staying home, when the celebration of Mass is imminent. Aptly St. Thomas, q. 71, a. 5: « If in the sin of omission there is understood only that which per se pertains to the notion of sin, thus sometimes the sin of omission is... without any act either interior or exterior... If, however, in the sin of omission there are also understood the causes or occasions of omitting, thus it is necessary that in the sin of omission there be some act »².

2º By the same name, recent authors call positive and negative voluntary acts, whether that which proceeds from the will as from a positive cause, namely from a voluntary act through a true and positive influx, or that which proceeds from it as from a negative cause, namely from a voluntary omission, or that which is deemed to proceed from the will not operating and omitting to act when it can and ought to act. These according to a different manner from the will proceed, and therefore by St. Thomas they are respectively called: voluntary direct, that which directly proceeds from it insofar as it is an agent (just as heating from heat) and toward which the will is borne; — and indirect³, that toward which it is not borne but which proceeds from it indirectly insofar as it could prohibit but does not prohibit, or does not act while it ought to act, just as the sinking of a ship is said to be from the helmsman to whom the steering is entrusted, insofar as he ceases from steering.

Voluntarium directum, therefore, is from a will that acts; indirectum is from a will that does not act when it ought to act.

60. Principles. I. That an omission be voluntary⁴, it is required and suffices that someone be able to place the act which is omitted and omit it advertently, nor is it required that he ought to place it: for he can as voluntarily omit Mass on a ferial day as on a feast day; — but that it be imputed to him, something more is required: for praise that he have intended the omission for a good end: for goodness is not contracted unless it be willed and intended as such; for fault, that he ought to have placed the omitted act: for fault is not present, unless someone transgress some precept.

II. For the effect of omission to be voluntary, it is required:

1° That the effect could and ought to have been morally foreseen, i.e., was foreseen in some way at least confusedly, obscurely, or indistinctly, insofar as someone at least doubted or suspected it would follow, or knew of the obligation to pay attention: for nothing is willed unless it is first known;

2° That it could have been avoided, and therefore that the omission freely took place: for the effect is not more voluntary than its cause;

3° As it ought to have been avoided, or as there was present an obligation not of omitting but of positing the omitted act, and indeed of positing it lest an effect follow: for a positive effect is not contained in an omission, and therefore an effect from a negative cause cannot be voluntary unless there is an obligation of impeding it. For, if the aforesaid obligation is lacking, since a simple omission can have no real influx into a positive effect, already every nexus, even moral, of causality between the omission and this effect is lacking, and consequently this effect is only permitted, not willed in the omission nor voluntary. On the contrary, if someone ought to avoid the effect, and does not avoid it, morally he is deemed and imputably is the cause of it, namely its privative cause. — But if the aforesaid conditions are present, even the effect is imputed to fault, because some precept is violated.

61. Observation. — The agent's intention cannot change the nature and causality of things, nor cause some effect to proceed from a certain action or omission as from a cause. Hence, if, given the absence of the third condition, the obligation to avoid the effect is lacking, that effect does not become voluntary even if one intends the omission precisely as a means for an evil effect, or even a good one: the effect will then be willed in itself, but it will not be voluntary, because the connection of causality between the effect and the omission is lacking, and this omission is not its true cause. Thus, if someone, precisely so that another may be immersed in water, refrains from bringing aid, while nevertheless he is not bound to bring aid, because, e.g., there is greater danger for himself. The intention, like the omission or the act placed with it, will be imputed to fault or praise, but not the effect itself; indeed, a good effect that follows the omission will never be imputed to praise, because, although it can occur with a good intention, it does not nevertheless arise from the good intention as from a cause by the omission.