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. 8, A. 3, 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 Obj. 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 Obj. 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 Obj. 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, 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. ________________________

FIFTH ARTICLE [I-II, Q. 12, Art. 5]

Whether Intention Is Within the Competency of Irrational Animals?

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.

Obj. 2:  Further, just as intention is of the end, so is enjoyment.  But enjoyment is in irrational animals, as stated above (Q. 11, A. 2).  Therefore intention is too.