What is a Virtual Intention? (Brief appendix from Reginald Garrigou-Lagrange, OP)
In this brief appendix,1 we will consider the following questions: What is a virtual intention? — How many kinds of virtual intention are there? — How does virtual intention differ from: actual formal intention, interpretative intention, and habitual intention?
Terminologically, we must remain sensitive to the differences in usage found in modern authors and in the works of St. Thomas himself. For example, many modern authors speak of habitual intention where St. Thomas speaks of virtual intention (whether explicit or implicit).
Division of intention. Intention can be divided as follows, through members that are opposed to each other (and, likewise, in a way that coheres with what is said in ST I-II, q. 1, a. 6, which occasions this particular appendix):

Actual-formal intention: when someone, by an actual and explicit act of the will, intends a known end.
Virtual intention: when someone acts for a given end without actual cognition and volition of that end. This can be divided into explicit-virtual and implicit-virtual as follows.
Explicit-virtual intention: when someone acts and chooses means in virtue of a prior actual and explicit intention that has not been retracted, even though he is not currently thinking about the end. For example, a doctor walking in the woods decides to gather herbs, on the basis of a prior intention to make medicine, even though he is not now thinking about this end.
Implicit-virtual intention: when someone does something that, by its very nature, tends toward a given end, as something less perfect tends toward its own perfection, whether he knows that end or not, provided that he does not divert it to another end violently and against the nature of his act. This intention—at least virtual and implicit—is what is at stake in this article when St. Thomas says that every beginning of something is ordered to its completion.2 Thus nature, with the formation of an embryo, virtually intends the [fully formed] human being. Likewise, a lower craftsman, constructing a work at the command of a higher craftsman, according to the rules of his own lower art, virtually and implicitly intends the end of the higher craftsman, which he perhaps does not know. Thus, he who lays the foundation for the house intends the house, and he who casts seed into the ground intends the fruit, which he is perhaps unaware of.
From this principle, St. Thomas proves that since every beginning of perfection is ordered toward its consummated perfection (which is through the ultimate end), every deliberate agent intends the ultimate end, if not explicitly in itself, at least implicitly in its inchoate form.
Some authors refer to this implicit-virtual intention as an “interpretative” intention. However, this is not correct, for properly speaking, an interpretative intention is something distinct from an implicit-virtual intention.
An interpretative intention is not concerned with what is or has, in fact, been done but, rather, provides a basis for judging what would have been the case if one had thought about the end. This is judged on the basis of the given subject’s disposition or customary manner of acting. For example, consider someone who gives alms to a poor relative whom he believes, under a pilgrim’s cloak, to be a stranger. This person is said to have interpretatively willed to give to his relative, because it is presumed that he would more readily have given to a relative than to a stranger, had known that this was his relative.
A habitual intention refers to the mere concomitance of some habit with an act, without that habit exercising any influence—whether actual or virtual—upon the act itself. For example, if a just person were to recite prayers while asleep, or, while in possession of his faculties, were to commit a venial sin, this is said to be referred to God habitually, on account of the concomitance of the habit of charity. This intention is distinguished from the ones that we have already discussed, for a habit gives only an inclination to act, though it needs an intention and directive judgment in order to pass into act, and, of itself, it is compatible with an intention and directive judgment that is, in some way, opposed (as is clear in the case of the just person committing a venial sin).
This division of intention runs through nearly the whole of theology, and many modern authors (e.g., Tanquerey) use the term “habitual intention” for what Thomists call “virtual implicit intention.” In fact, they sometimes say that “habitual voluntariness” arises from a volition once elicited and not retracted, even though it does not persist. This terminology does not coincide with that of St. Thomas. This confusion can be the cause of errors when authors cite texts of St. Thomas without taking care to ensure that they are using terms in the same sense as him.
Dubium: How long does an explicit-virtual intention last? (cf. Billuart).
Some say a one month, others a long time. But why would it not last into the first day of the following month, or into the following year? Such answers are not scientific, just as when sophists used to ask, “When do stones start to become a heap? Is it with the second? Or the third?...” Or, “What are the limits of a fortuitous, chance combination, as like the composition of the Iliad by randomly selected letters.”
Hence, something different needs to be said. More probably, per se, an explicit-virtual intention lasts until it is removed by a contrary intention, since it does not seem that there is assignable by which it would be destroyed. For, it is a given determination left over from a previous explicit-actual intention. Indeed, this determination does not depend on time (because it is something spiritual), nor does it, of itself, cease through non-use, even over a long span of time. Therefore, it remains that it ceases and is destroyed only by a per se contrary intention. If such a man were to die, this determination of his will, if it is good, would remain forever in purgatory or in heaven.
Nevertheless, per accidens, it can be destroyed through non-use over a long period of time, because, due to the instability of our mind united to the body, the very fact of long non-use makes space for other, contrary intentions, even without explicit attention, to arise and destroy the first, as St. Thomas teaches concerning habits (ST I–II, q. 53, a. 3).
An explicit-virtual intention can also be destroyed by something that is indirectly voluntary, namely by omission, or by voluntariness that is direct in its cause, that is, when a cause is voluntarily posited though having an effect, foreseen beforehand, contrary to the previous intention. For example: a physician intends to heal someone, but later drinks alcohol excessively, knowing the effect of excessive drinking. Afterward, he is not sufficiently in possession of himself to treat properly as he ought. He may perhaps heal only per accidens, or else harm the patient by giving a harmful remedy.
In practice, one recognizes that a virtual intention is influencing an action when a person, in possession of his faculties and acting morally, is not in fact thinking about the prior intention, though he is in such a disposition of mind that, if he were to reflect upon himself or were asked what he is doing or why he is acting, he would immediately appeal to his prior intention and reply that he is doing this for this or that reason.
Thus, when the term “virtual intention” is correctly understood, it is clearly established that everything a human being deliberately wills, he desires at least virtually and implicitly for the sake of the ultimate end, at least formally considered, namely, for the happiness of the acting agent.
Trans. note: This is translated anew from Reginald Garrigou-Lagrange, De beatitudine (Turin: Marietti, 1951), 59–62.↩︎
Trans. note: See ST I-II, q. 1, a. 6c:
It is necessary that whatever man desires, he desires for the sake of the ultimate end. This is evident for two reasons. First, whatever man desires, he desires under the aspect of the good. Now, if this is not desired as the perfect good (which is the ultimate end), then it must be desired as tending toward the perfect good, for every beginning of something is ordered to its consummation, as is clear in things that are done by nature and those done through art. Thus, every beginning of perfection is ordered toward consummated perfection, which comes about through the ultimate end. Second, the ultimate end moves the appetite in the same way that the first mover stands in other kinds of motion. Now, clearly, secondary moving causes do not move except insofar as they are moved by the first mover. Hence, secondary objects of desire do not move the appetite except as ordered to the first object of desire, which is the ultimate end.And, ibid., obj. 3 and ad 3:
↩︎Objection: whoever orders something to an end thinks about that end. Now, man does not always think about the ultimate end in everything that he desires or does. Therefore, we cannot say that man desires or does everything that he does for the sake of the ultimate end.
Response: One does not need to always to think about the ultimate end whenever he desires or acts. Rather, the power (virtus) of the first intention, which is directed to the ultimate end, remains in every act of desire for any particular thing, even if the ultimate end is not actually being thought about. This is akin to the person walking along a road, not needing to think about his destination at every single step.