Thomas Aquinas, Disputed Questions on Truth (De Veritate)

1. Powers are distinguished on the basis of their objects. Now the object of the intellect is the true, that of the will, the good. Since the good and the true are identical as to their real subject and differ in formal character, it therefore seems that the intellect and the will are really identical and differ only in formal character.

2. According to the Philosopher the will is in reason. It is therefore either the same as reason or a part of reason. But reason is the same power as the intellect. Then so is the will.

3. The faculties of the soul are commonly divided into the rational, the concupiscible, and the irascible. But the will is distinguished from the irascible and the concupiscible. It is therefore contained within the rational.

4. Wherever there is found an object which is the same in reality and in formal character, there is a single power. But the object of the will and of the practical intellect is the same in reality and in formal character, for the object of both is the good. Therefore the practical intellect is not a power different from the will. But the speculative intellect is not a power different from the practical because, according to the Philosopher, by extension the speculative intellect becomes practical. Therefore the will and the intellect (taken simply) are a single power.

5. To know the difference of two things from one another it is necessary for the same person to know both of the things differentiated. Similarly it must be the same person who knows and wills. But for the knowing of the difference between any two things, as "between white and sweet," it must be the same power which knows both. From this the Philosopher proves the existence of the central sense. By the same reasoning, then, it must be a single power which knows and wills; and so the intellect and the will are a single power, so it seems.

To the Contrary:

1'. The appetitive genus of powers of the soul is different from the intellective according to the Philosopher. But the will is listed under the appetitive. The will is therefore a power different from the intellect.

2'. The intellect can be forced, according to the Philosopher. But the will cannot be forced, as has been said. The intellect and the will are therefore not one and the same power.

REPLY:

The will and the intellect are distinct powers, even belonging to different genera of powers. That this may be clearly understood it should be noted that, since the distinction of powers is taken from the acts and objects, not just any difference at all among the objects reveals the distinctness of the powers but a difference in the objects precisely inasmuch as they are objects; and this will not be an accidental difference--I mean one which merely happens to be connected with the object taken specifically as object. It merely happens to the object of sense, for instance, inasmuch as it is sensible, to be animate or inanimate, though these differences are essential for the things which are sensed. It is accordingly not from these differences that the sense powers are diversified, but according as their objects are audible, visible, or tangible (for these are differences in the sensible inasmuch as it is sensible); that is to say, according to whether the objects are sensible through a medium or without a medium.

Now when essential differences of objects as objects are taken as dividing some specific object of the soul of themselves, by this fact powers are diversified but not genera of powers. Thus the sensible designates, not the object of the soul without qualification, but an object which of itself is divided by the aforesaid differences. Hence sight, hearing, and touch are distinct specific powers belonging to the same genus of powers of the soul, i.e., to sense. But when the differences considered divide the object taken in general, then from such a difference distinct genera of powers become known.

Something is said to be an object of the soul according as it has some relation to the soul. Hence, where we find different aspects of relatedness to the soul, there we find an essential difference in the object of the soul, and this indicates a distinct genus of the soul's powers. Now a thing is found to have a twofold relationship to the soul: one by which the thing itself is in the soul in the soul's manner and not in its own, the other by which the soul is referred to the thing in its own existence. Thus something is an object of the soul in two ways. (1) It is so inasmuch as it is capable of being in the soul, not according to its own act of being, but according to the manner of the soul--spiritually. This is the essential constituent of the knowable in so far as it is knowable. (2) Something is the object of the soul according as the soul is inclined and oriented to it after the manner of the thing itself as it is in itself. This is the essential constituent of the appetible in so far as it is appetible.

The cognitive and appetitive principles in the soul accordingly constitute distinct genera of powers. Hence, since the intellect is included in the cognitive, and the will in the appetitive, the will and the intellect must be powers that are distinct even generically.

Answers to Difficulties:

1. The distinction of powers is not manifested by the objects taken according to their reality but according to their formal aspect, because the formal aspects of the objects specify the operations of the powers. And so where there is a different formal aspect of the object, there we find a different power, even though it is the same thing which has the two formal aspects, as is the case with good and the true. This is also verified in material things. Air is modified by fire inasmuch as fire is hot, in view of the fact that air is potentially hot. But inasmuch as fire is luminous, air is modified by it in view of the fact that air is transparent. Nor is it the same potency in air by which it is called transparent and by which it is called potentially hot, even though it is the same fire which acts upon both potencies.

2. A power can be considered in two ways: either in reference to the object or in reference to the essence of the soul in which it is rooted. If the will is considered in reference to its object, it then belongs to a different genus from intellect. In this way will is distinguished from reason and intellect, as has been said.* But if the will is considered according to that in which it is rooted, then since the will, like the intellect, does not have a bodily organ, the will and the intellect are reduced to the same part of the soul. In this way the intellect or reason is sometimes taken as including both within it, and then the will is said to be in reason. On this basis the rational part, including both the intellect and the will, is distinguished from the irascible and the concupiscible.

3. From the above answer this also is clear.

4. The object of the practical intellect is not the good, but the true which is related to operation.

5. To will and to know are not acts of the same formal character, and so they cannot belong to the same power as can knowledge of what is sweet and what is white. Hence there is no parallel.