Thomas Aquinas

“ But since it is necessary, for the end of human life, that the appetitive power be inclined to something fixed, to which it is not inclined by the nature of the power, which has a relation to many and various things, therefore it is necessary that, in the will and in the other appetitive powers, there be certain qualities to incline them, and these are called habits. ”

“ Whence it follows that the intellective habit is chiefly on the part of the intellect itself; and not on the part of the phantasm, which is common to soul and body. And therefore we must say that the "possible" intellect is the subject of habit, which is in potentiality to many: and this belongs, above all, to the "possible" intellect. Wherefore the "possible" intellect is the subject of intellectual habits. ”

“ But since habit belongs to the first species of quality, it is prior to power, which belongs to the second species. Therefore habit is not in a power of the soul as its subject.
On the contrary, The Philosopher (Ethic. i, 13) puts various habits in the various powers of the soul.
I answer that, As we have said above (Q [49] , AA [2] ,3) , habit implies a certain disposition in relation to nature or to operation. If therefore we take habit as having a relation to nature, it cannot be in the soul---that is, if we speak of human nature: for the soul itself is the form completing the human nature ”

“ This saying of Maximus must be understood of material habits and accidents.
Reply to Objection 2: As to that which belongs to angels by their essence, they do not need a habit. But as they are not so far beings of themselves, as not to partake of Divine wisdom and goodness, therefore, so far as they need to partake of something from without, so far do they need to have habits.
Reply to Objection 3: In angels there are no essential parts: but there are potential parts, in so far as their intellect is perfected by several species, and in so far as their will has a relation to several things. ”

“ And therefore it is more suitable that habits should be in the powers of sensitive appetite than in the powers of sensitive apprehension, since in the powers of sensitive appetite habits do not exist except according as they act at the command of the reason. ”

“ The sensitive powers of dumb animals do not act at the command of reason; but if they are left to themselves, such animals act from natural instinct: and so in them there are no habits ordained to operations. ”

“ But Simplicius in his Commentary disapproves of this; for in this way heating would be in the third species, and heat in the first species of quality; whereas Aristotle puts heat in the third.
Wherefore Porphyrius, as Simplicius reports (Commentary) , says that passion or passion-like quality, disposition and habit, differ in bodies by way of intensity and remissness. For when a thing receives heat in this only that it is being heated, and not so as to be able to give heat, then we have passion, if it is transitory ”

“ There are in them, however, certain dispositions in relation to nature, as health and beauty. But whereas by man's reason brutes are disposed by a sort of custom to do things in this or that way, so in this sense, to a certain extent, we can admit the existence of habits in dumb animals: wherefore Augustine says (QQ. lxxxiii, qu. 36) : "We find the most untamed beasts, deterred by fear of pain, from that wherein they took the keenest pleasure ”