Reply Obj. 1:  As stated in De Anima iii, 9, “the will is in the reason.”  Hence, when Augustine ascribes consent to the reason, he takes reason as including the will.

Reply Obj. 2:  Sense, properly speaking, belongs to the apprehensive faculty; but by way of similitude, in so far as it implies seeking acquaintance, it belongs to the appetitive power, as stated above.

Reply Obj. 3:  Assentire (to assent) is, to speak, ad aliud sentire (to feel towards something); and thus it implies a certain distance from that to which assent is given.  But consentire (to consent) is “to feel with,” and this implies a certain union to the object of consent.  Hence the will, to which it belongs to tend to the thing itself, is more properly said to consent:  whereas the intellect, whose act does not consist in a movement towards the thing, but rather the reverse, as we have stated in the First Part (Q. 16, A. 1; Q. 27, A. 4; Q. 59, A. 2), is more properly said to assent:  although one word is wont to be used for the other [In Latin rather than in English.].  We may also say that the intellect assents, in so far as it is moved by the will. ________________________

SECOND ARTICLE [I-II, Q. 15, Art. 2]

Whether Consent Is to Be Found in Irrational Animals?

Objection 1:  It would seem that consent is to be found in irrational animals.  For consent implies a determination of the appetite to one thing.  But the appetite of irrational animals is determinate to one thing.  Therefore consent is to be found in irrational animals.

Obj. 2:  Further, if you remove what is first, you remove what follows.  But consent precedes the accomplished act.  If therefore there were no consent in irrational animals, there would be no act accomplished; which is clearly false.

Obj. 3:  Further, men are sometimes said to consent to do something, through some passion; desire, for instance, or anger.  But irrational animals act through passion.  Therefore they consent.

On the contrary, Damascene says (De Fide Orth. ii, 22) that “after judging, man approves and embraces the judgment of his counselling, and this is called the sentence,” i.e. consent.  But counsel is not in irrational animals.  Therefore neither is consent.

I answer that, Consent, properly speaking, is not in irrational animals.  The reason of this is that consent implies an application of the appetitive movement to something as to be done.  Now to apply the appetitive movement to the doing of something, belongs to the subject in whose power it is to move the appetite:  thus to touch a stone is an action suitable to a stick, but to apply the stick so that it touch the stone, belongs to one who has the power of moving the stick.  But irrational animals have not the command of the appetitive movement; for this is in them through natural instinct.  Hence in the irrational animal, there is indeed the movement of the appetite, but it does not apply that movement to some particular thing.  And hence it is that the irrational animal is not properly said to consent:  this is proper to the rational nature, which has the command of the appetitive movement, and is able to apply or not to apply it to this or that thing.