Prima Secundæ, Question 15 — Summa Theologiae
Article 1. Whether consent is an act of the appetitive or of the apprehensive power?
Objection 1. It would seem that consent belongs only to the apprehensive part of the soul. For Augustine (De Trin. xii, 12) ascribes consent to the higher reason. But the reason is an apprehensive power. Therefore consent belongs to an apprehensive power.
Objection 2. Further, consent is “co-sense.” But sense is an apprehensive power. Therefore consent is the act of an apprehensive power.
Objection 3. Further, just as assent is an application of the intellect to something, so is consent. But assent belongs to the intellect, which is an apprehensive power. Therefore consent also belongs to an apprehensive power.
On the contrary, Damascene says (De Fide Orth. ii, 22) that “if a man judge without affection for that of which he judges, there is no sentence,” i.e. consent. But affection belongs to the appetitive power. Therefore consent does also.
I answer that, Consent implies application of sense to something. Now it is proper to sense to take cognizance of things present; for the imagination apprehends the similitude of corporeal things, even in the absence of the things of which they bear the likeness; while the intellect apprehends universal ideas, which it can apprehend indifferently, whether the singulars be present or absent. And since the act of an appetitive power is a kind of inclination to the thing itself, the application of the appetitive power to the thing, in so far as it cleaves to it, gets by a kind of similitude, the name of sense, since, as it were, it acquires direct knowledge of the thing to which it cleaves, in so far as it takes complacency in it. Hence it is written (Wisdom 1:1): “Think of [Sentite] the Lord in goodness.” And on these grounds consent is an act of the appetitive power.
Reply to Objection 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 to Objection 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 to Objection 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 I:16:1; I:27:4; I:59:2, 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.
Article 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.
Objection 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.
Objection 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.
Reply to Objection 1. In irrational animals the determination of the appetite to a particular thing is merely passive: whereas consent implies a determination of the appetite, which is active rather than merely passive.
Reply to Objection 2. If the first be removed, then what follows is removed, provided that, properly speaking, it follow from that only. But if something can follow from several things, it is not removed by the fact that one of them is removed; thus if hardening is the effect of heat and of cold (since bricks are hardened by the fire, and frozen water is hardened by the cold), then by removing heat it does not follow that there is no hardening. Now the accomplishment of an act follows not only from consent, but also from the impulse of the appetite, such as is found in irrational animals.
Reply to Objection 3. The man who acts through passion is able not to follow the passion: whereas irrational animals have not that power. Hence the comparison fails.