Chapter 7

The activity and passivity of the soul relative to the body to which it is united

288. I have spoken about the nature of the rational soul as formal cause of the human being. I will now explain how the rational soul is the efficient cause of human actions. Formal cause posits and maintains an ens in being; efficient cause makes it act. The rational soul therefore, as formal cause, posits and maintains the human being in being; as efficient cause, it makes him act.

289. It is clear that the reason for the action of an ens must be sought in its form; form gives being, and everything acts according to its being, as the ancient saying states.(136) St. Thomas shows that the soul is the form of the composite, precisely because it is the proximate principle of all the composite's actions: Quo aliquid est actu, eo agit [A thing acts in so far as it is in act].

290. Our task then is to find in the form of the human being the origin of the soul's actions and of the potencies to which the actions are reduced. However, I will discuss specification of the human potencies issuing from the form of the human being in the second part which deals with the development of the soul. Here, I simply have to complete the reasoning already begun concerning the nexus between soul and body. To do this I will first explain how the soul is united to the body as form of the body - this posits the composite human subject in being - and then explain the commerce between the soul and the body, that is, how the soul is the sole cause of all the movements the human being produces in his body.

291. We have seen that the soul is united to the body not by means of phantasms or intelligible species (these are not acts of the soul), but by a constant, total and fundamental perception of the fundamental feeling. Let us now see how this principle, as our starting point, helps to explain both the action of the rational soul on the body it informs and its passivity.

Perception of a substantial feeling means identification between what is real (a feeling) and the essence of being (intuited by the intellect). It is an act of the rational soul with which the soul apprehends reality in relationship with idea. In short, it is a perception of the ens itself under two forms simultaneously. The ens is identical under the ideal and the real forms; its mode alone varies. Only one potency therefore is necessary to perceive it; this potency is the rational principle, in which the unity of the human subject is located. Thus, the rational principle attains the ens under two forms, because it is the faculty of ens and consequently of ens under all the forms in which ens communicates itself. The rational principle cannot apprehend a feeling and nothing more, because feeling pure and simple cannot manifest ens, which is the proper object of reason. Feeling however, united to being (intuited by the mind), acquires the nature of ens, or certainly reveals itself as such, and thus becomes the proper object of reason.(138) Feeling must therefore be considered in two modes: either pure and simple, in which case it is outside the rational order and must be attributed to another potency or principle, the irrational sentient principle, or be considered united to the essence of being, and be in this essence by means of rational perception. United in this way to being, it has become ens for us and entered the rational order; it now pertains to reason.(139) There is definitely feeling in the rational order, but only on condition that feeling has become an ens, that is, is identified with the essence of ens seen in the idea.

292. We have found the mode and condition by which the fundamental feeling enters the rational principle as its subject. We can now explain how this principle is able to act in and passively undergo action from the body.

The rational principle is certainly endowed with activity. We must presuppose this, or rather believe it from undoubted experience. The difficulty lies in explaining how the object on which the principle's activity is exercised can be presented to the principle, which can act only on its own object. Once we have found the mode in which the animal feeling can be received in the rational principle, our greatest difficulty is overcome. This mode can be only in the perception of a substantial feeling. Every other nexus would be neither a rational nor a true physical bond, nor would it explain the real connection of the body with a rational soul. Note that perception is a real physical conjunction of the perceiver with what is perceived. The Scholastics' dictum applies here: ex intellectu et intelligibili fit unum [a single thing is formed from the intellect and the intelligible], which, reduced to an exact statement, becomes: ex percipiente et percepto fit unum [a single thing is formed out of the perceiver and what is perceived].

293. Although this contact of the two substances, called contactus virtutis [contact through power] by St. Thomas, differs naturally from the contact of bodies, it gives rise to a kind of continuation between the two substances, placing one within the other, that is, within the sphere of action of the other. For example, when I use my hand to lift a body and place it elsewhere, the body adheres to my hand and becomes a kind of continuation of it, with the result that my hand's movement is communicated to the body. The same happens in the primal fundamental perception relative to the substantial feeling.

294. Let us now consider how this fundamental perception can explain the action of the rational soul on the body and vice versa.
The object of the perception we are discussing is the animalfundamental feeling. This feeling has a principle (the sentient element) and a term (that which is felt). The term (the felt) is the subjective body; the sentient element is the principle on whose activity, when posited in being, the felt depends. The sentient element is active, the felt passive. In brute animals the principle producing the spontaneous modifications and changes in their bodies is the sentient element, which in animals is called sensitive soul.

If, therefore, by means of the perception under discussion, the rational human soul is really united with all the animal feeling, it is united with the sentient element as well as the felt, the two elements from which that feeling results.

295. But the sentient element has an active nature. If then the rational soul can exercise its activity on the sentient element without in way altering the nature of this element, it can begin to act on the felt precisely because it can act on the sentient element.

296. On the other hand, the felt by its nature has to be passive relative to the sentient element which places it in act as felt. In this case, because the rational soul can perceive the felt only as a passive term of the sentient element, it must receive it exactly as it is in itself and modify it only by moving the sentient element.

297. The fact that the rational soul is unable to modify the felt directly means that it can only apprehend the felt. This explains why the rational soul, when receiving feelings and all senseexperiences, shows itself passive, although it is not really so: sense-experiences can only be apprehended by the rational principle, not directly modified by it because they are passive relative to the sentient principle, and their nature consists in this passivity.

298. We conclude: the activity of the soul on its body and the passivity demonstrated by the soul relative to the body are explained by means of the perception of the fundamental feeling. This gives us the very important, simple formula: 'The rational soul is as active on its own body as it is active on the sensitive principle,' nothing more.

299. I have shown how the rational soul united to the subjective body can be active relative to the latter. From this we easily see how the soul can also be active relative to the extrasubjective body and produce in it the movements perceived extrasubjectively. Relative to this, we need only recall what was said in the Anthropology about the relationship between the two bodies and about the two series of phenomena presented by these bodies.

The two bodies are simply one single body perceived differently. I have amply demonstrated their identity.(140)

300. I said there that I did not consider extrasubjective phenomena as effects of subjective phenomena, but solely as a parallel, harmonious series. This was sufficient for our discussion at the time, without further investigations. But although subjective phenomena are definitely not the cause of extrasubjective phenomena, the two series have a proximate cause in the sentient principle and a remote cause in the activity of the soul. Furthermore, the extrasubjective phenomena are partly the result of the body's relationships with the five special organs of exterior sensitivity.(141)

301. Ancient thinkers called the natural, radical activity of an ens nature, which, according to them, always tends to preserve and perfect itself, never to change and destroy itself.

302. The noble philosopher of Antwerp, Thomas Fyens, begins his discussion from this principle and shows that the soul cannot directly move itself in a way harmful to itself: 'The soul is a nature. Nature is certainly a principle of movement in natural things but only of movement that fits nature, not of every movement. It is not therefore an active principle of change.'(142) Hence, the soul cannot change its own body.
Hippocrates founded medicine on this principle, that is, on the energy of nature which always tends to heal, not to harm: *.

303. This teaching seems to some extent contrary to what I said in the Anthropology where I distinguished healing forces from disruptive forces in the human being.(143) Note however that disruptive forces do not pertain solely to animal nature but to other causes acting in and disrupting this nature.

304. Human beings are not solely animal: they have intelligence, which takes them far beyond the sphere of animality and can itself cause changes in disordered animality.

305. Furthermore, because human beings are free, they have the power to misdirect themselves and thus harm their animality, and even destroy it. Free nature withdraws from the above-mentioned law according to which it is the principle of only preservative, useful movements. This law is valid solely for natures which act from necessity, not for those that act freely.

Notes

(136) Anima enim est forma, forma autem est principium agendi, non materia. Forma enim est actus et dat esse: OPERARI AUTEM REQUIRITUR ESSE [The soul is form. Form, not matter, is the principle of action. It is act and imparts being: BEING IS REQUIRED FOR ACTION], T. Fyens, De viribus imaginationis, q. 1.

(137) S.T., I, q. 76, art. 1.

(138) The animal-fundamental feeling and its modifications never become object of the rational principle through a similitude (that is, through the intelligible species), as the Scholastics taught. But the rational principle itself perceives real feeling united to ideal being.

(139) Although Aristotle saw this union, he did not see that it was operative solely in perception. This opened the way to the error proper to the Arabs. In fact, Aristotle wrote that species intellecta calidi et frigidi talis existit qualis et rerum unaquaeque [the intellectual species of what is heat and cold exists exactly as the things themselves] (De motu animal., c. 6). He did not see that this is the case only in perception. He also wrote that scientia quae est actu est idem quod res [knowledge in act is the same as the thing] (De Anim., bk. 3, c. 5); elsewhere he says that 'the intellect becomes intelligible by understanding'. Although he says this happens by means of similitude, he has no hesitation in adding that species habent rerum virtutes [species have the energies of things] (De motu animalium, c. 6) [701, 20-22], thereby always confusing species with actual perception. The error of the Arabs has its root in a truth unnoticed by Aristotle.

(140) NE, vol. 2, 842; AMS, 197-229.

(141) AMS, 227-228.

(142) De viribus imaginationis, q. 6.

(143) AMS, 401-414.