Lecture 20 — Subdivisions of the Irrational Soul

One part of the irrational soul is the vegetative soul common to all living things. By vegetative, I understand that part that is the cause of nutrition and growth. Such a power of the soul is found in all things that assimilate food. It is found even in embryos and in the lowest forms of animal life. To these it is more reasonable to assign the vegetative part than some other. [231]

Because this power is common, it follows that it is not human. [233]

It seems that the vegetative part and potency of the soul are most active during sleep. Now, good and evil persons are hardly distinguishable in their sleep. Hence the saying that the happy are no better off than the miserable for half their lives. This is a reasonable doctrine, for sleep is a cessation from the operation according to which the soul is called good or evil. Yet perhaps certain activities do penetrate the soul of the sleeper gradually. In this way, the dreams of the virtuous become better than the dreams of other persons. But what we have now said on this subject will suffice. Therefore, discussion of the nutritive part must come to an end because it has no part in human virtue. [234]

Seemingly there is another part of the soul, irrational also but participating in reason to some extent. [236]

We praise the rational principle in the incontinent and continent man, for reason rightly induces to what is best. But something besides reason seems to be innate in them thay conflicts with reason and resists reason. As paralyzed members of the body are said to move wrongly to the left contrary to the will choosing the right, so also in the soul, for the movement of the incontinent are to things contrary to reason. While the uncontrolled movement can be seen in bodies, it is invisible in the soul. Nevertheless, we must judge that there is something in the soul besides reason that is contrary and resistant to reason. But how this differs from reason does not matter at present. [237]

Now this part seems to share in reason, as we have said. Therefore, as found in the continent man, it is obedient to reason. But it is even more fully subject in the sober and courageous man whose every act harmonizes with reason. [239]

Apparently the irrational part is twofold. The vegetative power does not partake of reason at all. But the concupiscible power and every appetitive power participate to some extent, because they heed and are obedient to reason. Therefore, we say that reason holds the place of a father and friends, but not of mathematicians. [240]

Persuasion, reproach, and entreaty in all cases indicate that the irrational principle is somewhat influenced by reason. [241]

If, however, we must say that this part shares in reason, then the rational will be of two kinds: one having reason principally and of itself, the other obedient to the reason as to a father. [242]

Virtue is divided according to this difference, for we call some virtues intellectual, others moral. Wisdom, understanding, and prudence are said to be intellectual virtues, while liberality and sobriety are called moral. When speaking of man’s good morals, we do not describe him as wise or intelligent, but as mild-tempered or sober. We do praise a person for acquiring the habit of wisdom, since praiseworthy habits are called virtues. [243]

231. One part of the irrational soul. After the philosopher has divided the parts of the soul into rational and irrational, here he subdivides the irrational part.

First, he presents one member of the subdivision;

second, he presents the other, at seemingly there is another part (1102b13; [236]).

In regard to the initial point, he does two things.

First, he mentions an irrational part of the soul.

Second, he shows that this part is not properly human, at because this power (1102b2; [233]).

He says first that one of the parts of the irrational soul is like the plant soul and is common to all things living here below. It is that part that is the cause of assimilation and growth. Such a part of the soul is found in every being that assimilates food, not only after birth but even before birth, as in embryos, which are obviously nourished and grow.

232. Likewise, this part of the soul is discovered not only in the highly organized animals having all the senses and endowed with local motion but also in the lowest animals, like oysters, having only the sense of touch and rooted to one place. Evidently, all these creatures live and have some kind of soul. But this vegetative type of soul, rather than some other part, is more reasonably assigned to these lowest animals because the effects of this part are more evident in them.

233. Then, at because this power (1102b2), he shows that the aforementioned part of the soul is not human.

First, he concludes this from the premises. We call human that which is distinctive of man. If, then, a part of the soul is altogether common, it will not be human.

234. Second, at it seems that (1102b3), he adds a proof from a particular evident sign. This part of the soul is found to be especially active during sleep, for when the natural heat has returned to the internal organs and the animal is asleep, digestion works better. But what is proper to man precisely as he is said to be good or evil operates only slightly during sleep. Good and evil persons are hardly distinguishable in their sleep. Hence the saying that the happy do not differ from the unhappy for half their life, which is spent in sleep. The reason is that judgment of the intellect is bound during sleep, and the external senses do not function, although the imagination and the power of nutrition are active.

235. It is reasonable that the good and evil, the happy and the unhappy, are indistinguishable while asleep, because that part of man by which he is called “good” ceases to function during sleep. Good and evil men differ while asleep not on account of a difference occurring during their slumbers, but because of what happened in their waking moments. Conscious activity gradually penetrates to the soul of the sleeper, such that the things a man has seen or heard or thought while awake present themselves to his imagination in sleep. In this way, the virtuous who spend their wakeful hours in good works have more edifying dreams than other persons who occupy their conscious moments with idle and evil works. What we have now said on this subject will suffice [234–5]. We conclude, then, from the premises [233–5], that the nutritive part of the soul is not adapted by nature to participate in human virtue.

236. Then, at seemingly there is (1102b13), he presents the other member of the division.

First, he indicates what he intends;

second, he proves his proposition, at we praise the rational (1102b14; [237]).

He says first that, besides the vegetative part of the soul, there seems to be another part, irrational like the vegetative but participating in reason to some extent. In this, it differs from the vegetative part, which has nothing whatsoever to do with human virtue, as was just said [235].

237. Then, at we praise the rational (1102b14), he proves his proposition:

first, that there is another part of the irrational soul;

second, that this part participates in reason, at now this part seems to share in reason (1102b25; [239]).

He proves the first by an argument taken from continent and incontinent men. In this matter, we praise the part of the soul having reason because it rightly deliberates and induces to what is best, as if by entreaty and persuasion. Both—continent and incontinent—choose to abstain from unlawful pleasures. But seemingly in both there is something innate in them other than reason, and this something conflicts with reason and resists it, or hinders it in the execution of its choice. Obviously, it is something irrational, since it is contrary to reason. The sensitive appetite, which desires what is pleasant to sense and at times opposes what reason judges absolutely good, would be such a thing. This appetite in the continent man is restrained by reason, for he certainly has evil desires, but his reason does not follow them. On the other hand, the appetite in the incontinent man overcomes reason, which is seduced by evil desires.

238. Then he adds an illustration. The members of the body are incapacitated when they cannot be controlled by the regulative power of the soul, as happens to paralytics and the intoxicated, who move to the left side when they wish to move to the right. This is true also of the souls of incontinent persons, who are moved to the opposite of what the reason chooses. But the process is not so apparent in the parts of the soul as in the parts of the body. We see clearly in what way a bodily member moves unnaturally, but the movement of the parts of the soul is not so obvious to us. Despite this, we must judge that there is something that is contrary to reason and resists it. But how this may differ from reason—whether by subject or by concept alone—does not matter at present.

239. Then, at now this part (1102b25), he shows that an irrational part of this kind participates in reason.

His first argument is based on acts taking place within man;

his second, at persuasion, reproach, and entreaty (1102b33; [241]), is based on acts external to man.

With the first he does two things.

First, he shows that this irrational part participates in reason.

Second, he finishes the treatment of the difference of this irrational part from the part presented above, at apparently the irrational part (1102b28; [240]).

He says first that the irrational part, of which we have now spoken [233–5], seems in some way to participate in reason, as was just said [236]. This is obvious in the continent man, whose sensitive appetite obeys reason. Although he may have evil desires, nevertheless he does not act according to them, but according to reason. In the sober or temperate man, this part of the soul is even more fully subject to reason. Such a man has so subdued his sensitive appetite that evil desires in him are not vehement. We may say the same of the courageous man and of anyone endowed with the habit of moral virtue. The reason is that, in these men, nearly everything harmonizes with reason, both external actions and internal desires.

240. Then, at apparently the irrational (1102b28), he concludes the difference between the two irrational parts from the premises. He says that, according to the premises, the irrational part is apparently twofold. Now the vegetative part, found in plants, does not partake of reason in any way, for it is not obedient to the direction of reason. But the concupiscible power and every appetitive power, like the irascible emotion and the will, participate in reason in some measure, because they heed the movement of the reason and are obedient to its regulations. Hence, we say reason holds the place of a father giving guidance and of friends offering advice. But reason here does not play the role of a mere theorist, like the reason of a mathematician, for the irrational part of the soul does not partake in any way of reason understood in this sense.

241. Then, at persuasion, reproach, and entreaty (1102b33), he shows through the things externally done that the irrational part participates in reason. In his opinion, this is indicated from the fact that the persuasion of friends, the reproach of superiors, and the entreaties of inferiors aim to keep a man from following his desires. But all these would be useless unless this part of the irrational soul could share in reason. From this, too, it is apparent that reason is not controlled by the movements of the passions of the sensitive appetite, but quite the contrary—reason can restrain such movements. Therefore, reason is not governed by the motions of the heavenly bodies, which can effect some change in the sensitive appetite of the soul through a change in the human body. Since the intellect or reason is not a faculty of any bodily organ, it is not directly subject to the action of any bodily power. The same is true of the will that is in the reason, as was said in De anima. (De anima 3.3.427a21; see Aquinas, In III de an., lec. 4, nn.617–621.)

242. Then, at if, however (1103a1), he subdivides the other member of the first division, the rational part of the soul. According to him (if we must say that that part of the soul that participates in reason is rational in some way), the rational part will be of two kinds: one, having reason principally and in itself, is rational by nature, but the other is inherently adapted to obey reason as a father, and is called rational by participation. In accord with this, one member is contained under both rational and irrational. Now, one part of the soul, the vegetative, is irrational alone; another part is rational alone, the intellect and reason. Still another part is of itself irrationa,l but rational by participation, like the sensitive appetite and the will.

243. Then, at virtue is divided (1103a3), he divides virtue according to this difference in the parts of the soul. He says that virtue is designated or divided according to the above-mentioned difference in the parts of the soul. Since human virtue perfects the work of man that is done according to reason, human virtue must consist in something reasonable. Since the reasonable is of two kinds, by nature and by participation, it follows that there are two kinds of human virtue. One of these is placed in what is rational by nature and is called intellectual. The other is placed in what is rational by participation, that is, in the appetitive part of the soul, and is called moral. Therefore, he says, we call some of the virtues intellectual and some moral. Wisdom, understanding, and prudence are said to be intellectual virtues, while liberality and sobriety are called moral.

244. He proves this point from human praises. When we wish to praise someone for good morals, we do not describe him as wise and intelligent, but as sober and mild-tempered. We do not praise a man for good morals alone but also for the habit of wisdom. Praiseworthy habits are called virtues. Therefore, besides the moral virtues, there are also intellectual virtues like wisdom, understanding, and some others of this kind. Thus ends book 1.