In rebus voluntariis, idem motus est intentio finis et voluntas eius quod est ad finem, quia voluntas fertur in id quod est ad finem, propter finem.
In things pertaining to the will, the intention of the end is the same movement as the willing of the means, because the will is moved to the means for the sake of the end.
Finis, inquantum est res quaedam, est aliud voluntatis obiectum quam id quod est ad finem. Sed inquantum est ratio volendi id quod est ad finem, est unum et idem obiectum.
The end, considered as a thing, is other than the object of the will that is the means to that end. But insofar as the end is the formal aspect for willing the means, they are one and the same object.
Cum enim dico, "volo medicinam propter sanitatem," non designo nisi unum motum voluntatis. Cuius ratio est quia finis ratio est volendi ea quae sunt ad finem.
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 the formal aspect of this is that the end is the formal aspect for willing the means.
Idem autem actus cadit super obiectum, et super rationem obiecti; sicut eadem visio est coloris et luminis, ut supra dictum est.
Now the object, and the formal aspect by 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 (q8 a3 ad 2).
Et est simile de intellectu: quia si absolute principium et conclusionem consideret, diversa est consideratio utriusque; in hoc autem quod conclusioni propter principia assentit, est unus actus intellectus tantum.
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.
Motus qui est unus subiecto, potest ratione differre: secundum principium et finem.
A movement which is one as to the subject, may differ according to the formal aspect: as to its beginning and end.
Sic igitur inquantum motus voluntatis fertur in id quod est ad finem, prout ordinatur ad finem, est electio. Motus autem voluntatis qui fertur in finem, secundum quod acquiritur per ea quae sunt ad finem, vocatur intentio.
Accordingly, in so far as the movement of the will is to the means, as ordained to the end, it is "choice". But the movement of the will to the end, as acquired by the means, it is called "intention".
Cuius signum est quod intentio finis esse potest, etiam nondum determinatis his quae sunt ad finem, quorum est electio.
A sign of this is that we can have intention of the end, without having determined the means, which are the object of choice.