Summa Theologica, by St. Thomas Aquinas, , at sacred-texts.com
We must now consider Intention: concerning which there are five points of inquiry:
(1) Whether intention is an act of intellect or of the will?
(2) Whether it is only of the last end?
(3) Whether one can intend two things at the same time?
(4) Whether intention of the end is the same act as volition of the means?
(5) Whether intention is within the competency of irrational animals?
Objection 1: It would seem that intention is an act of the intellect, and not of the will. For it is written (Mat. 6:22): "If thy eye be single, thy whole body shall be lightsome": where, according to Augustine (De Serm. Dom. in Monte ii, 13) the eye signifies intention. But since the eye is the organ of sight, it signifies the apprehensive power. Therefore intention is not an act of the appetitive but of the apprehensive power.
Objection 2: Further, Augustine says (De Serm. Dom. in Monte ii, 13) that Our Lord spoke of intention as a light, when He said (Mat. 6:23): "If the light that is in thee be darkness," etc. But light pertains to knowledge. Therefore intention does too.
Objection 3: Further, intention implies a kind of ordaining to an end. But to ordain is an act of reason. Therefore intention belongs not to the will but to the reason.
Objection 4: Further, an act of the will is either of the end or of the means. But the act of the will in respect of the end is called volition, or enjoyment; with regard to the means, it is choice, from which intention is distinct. Therefore it is not an act of the will.
On the contrary, Augustine says (De Trin. xi, 4,8,9) that "the intention of the will unites the sight to the object seen; and the images retained in the memory, to the penetrating gaze of the soul's inner thought." Therefore intention is an act of the will.
I answer that, Intention, as the very word denotes, signifies, "to tend to something." Now both the action of the mover and the movement of thing moved, tend to something. But that the movement of the thing moved tends to anything, is due to the action of the mover. Consequently intention belongs first and principally to that which moves to the end: hence we say that an architect or anyone who is in authority, by his command moves others to that which he intends. Now the will moves all the other powers of the soul to the end, as shown above (Q, A). Wherefore it is evident that intention, properly speaking, is an act of the will.
Reply to Objection 1: The eye designates intention figuratively, not because intention has reference to knowledge, but because it presupposes knowledge, which proposes to the will the end to which the latter moves; thus we foresee with the eye whither we should tend with our bodies.
Reply to Objection 2: Intention is called a light because it is manifest to him who intends. Wherefore works are called darkness because a man knows what he intends, but knows not what the result may be, as Augustine expounds (De Serm. Dom. in Monte ii, 13).
Reply to Objection 3: The will does not ordain, but tends to something according to the order of reason. Consequently this word "intention" indicates an act of the will, presupposing the act whereby the reason orders something to the end.
Reply to Objection 4: Intention is an act of the will in regard to the end. Now the will stands in a threefold relation to the end. First, absolutely; and thus we have "volition," whereby we will absolutely to have health, and so forth. Secondly, it considers the end, as its place of rest; and thus "enjoyment" regards the end. Thirdly, it considers the end as the term towards which something is ordained; and thus "intention" regards the end. For when we speak of intending to have health, we mean not only that we have it, but that we will have it by means of something else.
Objection 1: It would seem that intention is only of the last end. For it is said in the book of Prosper's Sentences (Sent. 100): "The intention of the heart is a cry to God." But God is the last end of the human heart. Therefore intention is always regards the last end.
Objection 2: Further, intention regards the end as the terminus, as stated above (A, ad 4). But a terminus is something last. Therefore intention always regards the last end.
Objection 3: Further, just as intention regards the end, so does enjoyment. But enjoyment is always of the last end. Therefore intention is too.
On the contrary, There is but one last end of human wills, viz. Happiness, as stated above (Q, A). If, therefore, intentions were only of the last end, men would not have different intentions: which is evidently false.
I answer that, As stated above (A, ad 4), intention regards the end as a terminus of the movement of the will. Now a terminus of movement may be taken in two ways. First, the very last terminus, when the movement comes to a stop; this is the terminus of the whole movement. Secondly, some point midway, which is the beginning of one part of the movement, and the end or terminus of the other. Thus in the movement from A to C through B, C is the last terminus, while B is a terminus, but not the last. And intention can be both. Consequently though intention is always of the end, it need not be always of the last end.
Reply to Objection 1: The intention of the heart is called a cry to God, not that God is always the object of intention, but because He sees our intention. Or because, when we pray, we direct our intention to God, which intention has the force of a cry.
Reply to Objection 2: A terminus is something last, not always in respect of the whole, but sometimes in respect of a part.
Reply to Objection 3: Enjoyment implies rest in the end; and this belongs to the last end alone. But intention implies movement towards an end, not rest. Wherefore the comparison proves nothing.
Objection 1: It would seem that one cannot intend several things at the same time. For Augustine says (De Serm. Dom. in Monte ii, 14,16,17) that man's intention cannot be directed at the same time to God and to bodily benefits. Therefore, for the same reason, neither to any other two things.
Objection 2: Further, intention designates a movement of the will towards a terminus. Now there cannot be several termini in the same direction of one movement. Therefore the will cannot intend several things at the same time.
Objection 3: Further, intention presupposes an act of reason or of the intellect. But "it is not possible to understand several things at the same time," according to the Philosopher (Topic. ii, 10). Therefore neither is it possible to intend several things at the same time.
On the contrary, Art imitates nature. Now nature intends two purposes by means of one instrument: thus "the tongue is for the purpose of taste and speech" (De Anima ii, 8). Therefore, for the same reason, art or reason can at the same time direct one thing to two ends: so that one can intend several ends at the same time.
I answer that, The expression "two things" may be taken in two ways: they may be ordained to one another or not so ordained. And if they be ordained to one another, it is evident, from what has been said, that a man can intend several things at the same time. For intention is not only of the last end, as stated above (A), but also of an intermediary end. Now a man intends at the same time, both the proximate and the last end; as the mixing of a medicine and the giving of health.
But if we take two things that are not ordained to one another, thus also a man can intend several things at the same time. This is evident from the fact that a man prefers one thing to another because it is the better of the two. Now one of the reasons for which one thing is better than another is that it is available for more purposes: wherefore one thing can be chosen in preference to another, because of the greater number of purposes for which it is available: so that evidently a man can intend several things at the same time.
Reply to Objection 1: Augustine means to say that man cannot at the same time direct his attention to God and to bodily benefits, as to two last ends: since, as stated above (Q, A), one man cannot have several last ends.
Reply to Objection 2: There can be several termini ordained to one another, of the same movement and in the same direction; but not unless they be ordained to one another. At the same time it must be observed that what is not one in reality may be taken as one by the reason. Now intention is a movement of the will to something already ordained by the reason, as stated above (A, ad 3). Wherefore where we have many things in reality, we may take them as one term of intention, in so far as the reason takes them as one: either because two things concur in the integrity of one whole, as a proper measure of heat and cold conduce to health; or because two things are included in one which may be intended. For instance, the acquiring of wine and clothing is included in wealth, as in something common to both; wherefore nothing hinders the man who intends to acquire wealth, from intending both the others.
Reply to Objection 3: As stated in the FP, Q, A; FP, Q, A; FP, Q, A it is possible to understand several things at the same time, in so far as, in some way, they are one.
Objection 1: It would seem that the intention of the end and the volition of the means are not one and the same movement. For Augustine says (De Trin. xi, 6) that "the will to see the window, has for its end the seeing of the window; and is another act from the will to see, through the window, the passersby." But that I should will to see the passersby, through the window, belongs to intention; whereas that I will to see the window, belongs to the volition of the means. Therefore intention of the end and the willing of the means are distinct movements of the will.
Objection 2: Further, acts are distinct according to their objects. But the end and the means are distinct objects. Therefore the intention of the end and the willing of the means are distinct movements of the will.
Objection 3: Further, the willing of the means is called choice. But choice and intention are not the same. Therefore intention of the end and the willing of the means are not the same movement of the will.
On the contrary, The means in relation to the end, are as the mid-space to the terminus. Now it is all the same movement that passes through the mid-space to the terminus, in natural things. Therefore in things pertaining to the will, the intention of the end is the same movement as the willing of the means.
I answer that, The movement of the will to the end and to the means can be considered in two ways. First, according as the will is moved to each of the aforesaid absolutely and in itself. And thus there are really two movements of the will to them. Secondly, it may be considered accordingly as the will is moved to the means for the sake of the end: and thus the movement of the will to the end and its movement to the means are one and the same thing. For when I say: "I wish to take medicine for the sake of health," I signify no more than one movement of my will. And this is because the end is the reason for willing the means. Now the object, and that by reason of which it is an object, come under the same act; thus it is the same act of sight that perceives color and light, as stated above (Q, A, ad 2). And the same applies to the intellect; for if it consider principle and conclusion absolutely, it considers each by a distinct act; but when it assents to the conclusion on account of the principles, there is but one act of the intellect.
Reply to Objection 1: Augustine is speaking of seeing the window and of seeing, through the window, the passersby, according as the will is moved to either absolutely.
Reply to Objection 2: The end, considered as a thing, and the means to that end, are distinct objects of the will. But in so far as the end is the formal object in willing the means, they are one and the same object.
Reply to Objection 3: A movement which is one as to the subject, may differ, according to our way of looking at it, as to its beginning and end, as in the case of ascent and descent (Phys. iii, 3). Accordingly, in so far as the movement of the will is to the means, as ordained to the end, it is called "choice": but the movement of the will to the end as acquired by the means, it is called "intention." A sign of this is that we can have intention of the end without having determined the means which are the object of choice.
Objection 1: It would seem that irrational animals intend the end. For in things void of reason nature stands further apart from the rational nature, than does the sensitive nature in irrational animals. But nature intends the end even in things void of reason, as is proved in Phys. ii, 8. Much more, therefore, do irrational animals intend the end.
Objection 2: Further, just as intention is of the end, so is enjoyment. But enjoyment is in irrational animals, as stated above (Q, A). Therefore intention is too.
Objection 3: Further, to intend an end belongs to one who acts for an end; since to intend is nothing else than to tend to something. But irrational animals act for an end; for an animal is moved either to seek food, or to do something of the kind. Therefore irrational animals intend an end.
On the contrary, Intention of an end implies ordaining something to an end: which belongs to reason. Since therefore irrational animals are void of reason, it seems that they do not intend an end.
I answer that, As stated above (A), to intend is to tend to something; and this belongs to the mover and to the moved. According, therefore, as that which is moved to an end by another is said to intend the end, thus nature is said to intend an end, as being moved to its end by God, as the arrow is moved by the archer. And in this way, irrational animals intend an end, inasmuch as they are moved to something by natural instinct. The other way of intending an end belongs to the mover; according as he ordains the movement of something, either his own or another's, to an end. This belongs to reason alone. Wherefore irrational animals do not intend an end in this way, which is to intend properly and principally, as stated above (A).
Reply to Objection 1: This argument takes intention in the sense of being moved to an end.
Reply to Objection 2: Enjoyment does not imply the ordaining of one thing to another, as intention does, but absolute repose in the end.
Reply to Objection 3: Irrational animals are moved to an end, not as though they thought that they can gain the end by this movement; this belongs to one that intends; but through desiring the end by natural instinct, they are moved to an end, moved, as it were, by another, like other things that are moved naturally.