Book Three — Providence, Chapter 26 — Summa Contra Gentiles
[1] Now, since an intellectual substance, through its own operation, attains to God, not only by understanding, but also through an act of will, by desiring and loving Him and by taking delight in Him, it may appear to someone that the ultimate end and the ultimate felicity of man do not lie in knowing, but in loving God, or in some other act of will relating to Him.
[2] Especially so, since the object of the will is the good, and the good has the rational character of an end, while the true which is the object of the intellect does not have the rational character of an end, except inasmuch as it is also a good. Consequently, it does not seem that Man attains his ultimate end through an act of understanding, but rather, through an act of will.
[3] Again, the ultimate perfection of operation is delight “which perfects activity as beauty perfects youth,” as the Philosopher says in Ethics X [4: 1174b 31]. So, if perfect operation is the ultimate end, it appears that the ultimate end is more in accord with an operation of the will than of the intellect.
[4] Besides, delight seems to be so much an object of desire for its own sake that it is never desired for the sake of something else; indeed, it is foolish to ask a person why he wishes to be delighted. Now, this is characteristic of the ultimate end: it is sought for its own sake. Therefore, the ultimate end lies in an operation of the will rather than of the intellect, it would seem.
[5] Moreover, all men agree to the fullest extent in their appetite for the ultimate end, for it is natural. Now, more men seek delight than knowledge. So, it would seem that the end is delight rather than knowledge.
[6] Furthermore, the will seems to be a higher power than the intellect, for the will moves the intellect to its act; indeed, the intellect actually considers, whenever it wills to, what it retains habitually. Therefore, the action of the will seems to be nobler than the action of the intellect. And so, it seems that the ultimate end, which is happiness, consists rather in an act of will than in an act of intellect.
[7] However, it can be shown that this view is quite impossible.
[8] Since happiness is the proper good of an intellectual nature, happiness must pertain to an intellectual nature by reason of what is proper to that nature. Now, appetite is not peculiar to intellectual nature; instead, it is present in all things, though it is in different things in different ways. And this diversity arises from the fact that things are differently related to knowledge. ~For things lacking knowledge entirely have natural appetite only. And things endowed with sensory knowledge have, in addition, sense appetite, under which irascible and concupiscible powers are included. But things possessed of intellectual knowledge also have an appetite proportionate to this knowledge, that is, will. So, the will is not peculiar to intellectual nature by virtue of being an appetite, but only in so far as it depends on intellect. However, the intellect, in itself, is peculiar to an intellectual nature. Therefore, happiness, or felicity, consists substantially and principally in an act of the intellect rather than in an act of the will.
[9] Again, in the case of all powers that are moved by their objects the objects are naturally prior to the acts of these powers, just as a mover is naturally prior to the moving of its passive object. Now, the will is such a power, for the object of appetition moves the appetite. So, the will’s object is naturally prior to its act. Hence, its first object precedes every one of its acts. Therefore, no act of the will can be the first thing that is willed. But that is what the ultimate end is, in the sense of happiness. So, it is impossible for happiness, or felicity, to be the very act of the will.
[10] Besides, for all the powers capable of reflection on their own acts, the act of such a power must first be brought to bear on some other object, and then directed to its own act. If the intellect is to understand itself in the act of understanding, it must first be taken that it understands something, and then, as a result, that it understands that it is understanding. For, this act of understanding which the intellect understands pertains to some object. Hence, it is necessary either to proceed through an endless series, or, if we are to come to a first object of understanding, it will not be the act of understanding but rather some intelligible thing. Likewise, the first willed object must not be the will’s act but some other good thing. But, for an intellectual nature, the first thing that is willed is happiness itself, or felicity, since it is for the sake of this happiness that we will whatever we will. Therefore, it is impossible for felicity to consist essentially in an act of the will.
[11] Moreover, each thing possesses its true nature by virtue of the components which make up its substance. Thus, a real man differs from a painting of a man by virtue of the things that constitute the substance of man. Now, in their relation to the will act, true happiness does not differ from false happiness. In fact, the will, when it desires, loves or enjoys, is related in just the same way to its object, whatever it may be that is presented to it as a highest good, whether truly or falsely. Of course, whether the object so presented is truly the highest good, or is false, this distinction is made on the part of the intellect. Therefore, happiness, or felicity, essentially consists in understanding rather than in an act of the will.