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. 9, A. 1).  Wherefore it is evident that intention, properly speaking, is an act of the will.

Reply Obj. 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 Obj. 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 Obj. 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 Obj. 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. ________________________

SECOND ARTICLE [I-II, Q. 12, Art. 2]

Whether Intention Is Only of the Last End?

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.

Obj. 2:  Further, intention regards the end as the terminus, as stated above (A. 1, ad 4).  But a terminus is something last.  Therefore intention always regards the last end.

Obj. 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. 1, A. 7).  If, therefore, intentions were only of the last end, men would not have different intentions:  which is evidently false.