But the concupiscible power, being a part of the sensitive appetite, cannot tend to wisdom, which is not apprehended by the senses. Therefore love is not in the concupiscible power. Therefore we must not say absolutely that love is in the concupiscible power. But natural love seems to pertain rather to the natural powers, which belong to the vegetal soul. Therefore love is not simply in the concupiscible power.
Wherefore love differs according to the difference of appetites.
And there is another appetite arising from an apprehension in the subject of the appetite, but from necessity and not from free-will. Again, there is another appetite following freely from an apprehension in the subject of the appetite. So that sensitive love is in the sensitive appetite, just as intellectual love is in the intellectual appetite. And it belongs to the concupiscible power, because it regards good absolutely, and not under the aspect of difficulty, which is the object of the irascible faculty. The words quoted refer to intellectual or rational love.