Chapter 13

The soul's activity on the extrasubjective body

420. Summarising what has been said, we have seen that:

1. The rational soul is united to the animal fundamental feeling through a natural, immanent perception.

2. Because the fundamental feeling consists of two elements, that is, the sentient and the felt, the rational soul is united to both.

3. The rational soul's union with the felt element is the same as its union with its own subjective body; through this union the soul becomes passive because the body is passive.

4. Through its union with the sentient element, the soul is active, and can act on this principle which governs the felt or body. Thus it can act on the body.

5. The sentient principle in animals is that which constitutes the sensitive soul.

6. The sentient principle's indivisible union with the felt element is the union we have explained at length in Anthropology.

421. While demonstrating these things I only touched upon the extrasubjective body. But an explanation of the nexus between soul and subjective body is also an explanation of the relationship of the soul with the extrasubjective body. The extrasubjective body is substantially the subjective body, although possessed of other appearances because of the different mode and potencies through which we perceive it.

However, I do want to add something here. Philosophers have never really known what the subjective body is. They have always conceived corporeal substance wrapped in the phenomena given by external, extrasubjective experience. When they asked the question, 'How does the soul act in the body and viceversa?', they always understood by body the extrasubjective body. Hence their predicament.
To avoid this difficulty we must demonstrate the relationship between the two bodies which we perceive. When we know this relationship, we can easily understand how the soul's action on the extrasubjective body is exercised as a result of its action on the subjective body.

This gives us confidence that we can lift a part of the heavy veil covering the mystery of sensation. We will gain much light by explaining the nexus between extrasubjective and subjective phenomena, a nexus we have already found in the identity of the space where these two kinds of phenomena converge.

422. Let us grant therefore that a fundamental feeling exists, diffused through all the sensitive parts of the human body in such a way that it occupies the identical space as the body where the extrasubjective phenomena are manifested. For example, the nerve which I see with my eyes and touch with my hands (extrasubjective phenomena) is where subjective feeling adheres. This feeling is such that it makes its possessor feel the nerve naturally but in a different way, a direct way. Granted this, all movements produced in the nerve will show themselves to external observation as extrasubjective phenomena and also effectively modify the subjective feeling inherent in the nerve.

Note, however, that although we say a subjective feeling is diffused naturally in all the space occupied by the nerve, we do not mean that this space is outlined and shaped in the natural, fundamental subjective feeling. On the contrary, space is shaped and limited only through external sensation, which is extrasubjective phenomena. One of these phenomena is that of surface sensations which I discussed in Anthropology but, as far as I know, has never been considered by philosophers.

Surface sensations, properly speaking, are those which surround bodies and give rise to the forms, determined sizes and proportions of bodies; in a word, surface sensations furnish us with all the knowledge supplied by these elements. It is precisely in this way that the external world is, as it were, manufactured by our external sensitivity. On the other hand, no such perceptions are offered by the internal world locked within subjective feeling. The space occupied by the fundamental feeling, because unlimited and unrelated to other spaces, remains obscure and simple in appearance; it is unsuitable for stimulating attention. This space, I repeat, is that same space which the external sensations later define, shape and in a certain way illumine and distinguish from the totality of space. In it the corporeal organ to which feeling adheres receives movement.

423. Let us suppose that this body or corporeal organ changes place without any relative movement of the molecules or particles that compose it. Certainly, nothing would happen in the internal feeling inherent in the body that would indicate the place-change to an observer. The change of place is sensible only through the relative position of the external bodies which is presented to us not by the subjective fundamental feeling but by the accidental sensations and extrasubjective phenomena.(178) If, however, internal movements arise in the living body to which feeling adheres, if for example a nerve retracts or extends because it has a certain animal elasticity or contractility, the feeling inherent in the nerve will be restricted to a smaller space or diffused into a greater space. Note carefully, I do not mean that feeling in the nerve presents movement to our consciousness; movement, I repeat, is known only in virtue of extrasubjective phenomena. In other words, the rapid shortening and lengthening of the felt nerve must necessarily produce a modification in the fundamental feeling; the nerve's activity must be stimulated because the stimulus forces it to change its disposition. When feeling is stimulated in this way by foreign energy, and its activity shaken up, stimulated and intensified, it must produce a felt modification, because every activity of feeling is felt.

424. But what manner does this modification take? What phenomena are presented by this sensitive activity aroused from its quiet state? It is impossible to say a priori; only experience can inform us. Thus, we know from experience that such phenomena are transient sensations, colours, sounds, odours, tastes, sensations of touch, etc; they are therefore stimulations of feeling, of the fundamental feeling.(179) Although it was difficult to explain how movement of a body could produce these stimulations in a feeling that is not body, the difficulty seems to disappear once we have found a fundamental feeling which, adhering essentially to the body, diffuses itself in the space of the body. However, we must note that to draw certain special feelings from the fundamental feeling, it has to be acted upon and aroused by particular stimuli in accordance with particular laws and movements, and in particular organs to which it unceasingly adheres.

425. I say 'particular laws' because not all movements of the organs stimulate the fundamental feeling in such a way that sensations are aroused. For this, certain conditions are necessary, for example, a nerve apparatus, one kind of stimulation rather than another, a given rate of vibrations. All this is still mostly unknown.

426. Let me add an observation about the undeniable fact that several organs must concur in the production of one sensation. For example, to produce sight, the concurrent action of the optic nerves, the lobes of the cerebrum and the cerebellum, the optic thalami, etc. are required. This necessity of such a complex apparatus of organs to produce one, simple sensation will cause no surprise if we meditate carefully on the following truths already discussed:

1. The sentient principle is one and simple.

2. Sensation requires an aroused activity of the sensitive principle, the real cause of sensation.

3. The whole of the fundamental felt element in all its extension is in the unextended sensitive principle, not as one extended thing in another extended thing, but as the felt in the sentient. We have called this a 'relationship of sensility'.

4. The sensitive principle is stimulated, aroused, actuated by internal movements produced in the organs, which are parts of the felt.

5. These movements, although varied and pertaining to different organs, all tend to a single effect, the stimulation of the sensitive principle by the contraction, intensification and successive dilation of the felt element, its term.

6. Although every intensification and dilation is followed by some modification of the feeling and of the activity of the sensitive principle, it causes no surprise that movements of a certain multiplicity, variety, frequency, etc. are required to explain particular sensations in the sensitive principle.

427. All these facts seem to shed great light on the origin of sensation, which was inexplicable before the discovery of the distinction between subjective and extrasubjective phenomena. To explain sensation is to solve the great question of the interaction between soul and body. Human thought, limited to the sphere of extrasubjective experience, strove vainly to invent hypotheses, without ever finding a real communication between spirit and body.

Consequently, philosophers divided into two classes. Some counterfeited the concept of the spirit and made it extrasubjective; they imagined it as a very subtle body which escaped the senses, and thus made possible reciprocal action between the spirit and cruder bodies. Others were well aware that this explanation destroyed the spiritual ens; it was the kind of materialism which could explain a mechanical relationship, but never a sense-based relationship. Thus, they denied any physical influence between body and soul, and in its place either dreamt up various hypotheses(180) or more wisely called the problem a 'mystery' and, with this fine, decent word, put a stop to further discussion amongst themselves and amongst all popularisers who wanted to pursue the matter further.

Readers will find it interesting, I think, if I comment on the strange thinking which the first kind of thinkers had to pursue in order to imagine how the spirit, like some kind of extremely fine air, entered our dense, bulky body through a succession of other intermediate, more subtle bodies. I will use Jean Fernel's exposition of these systems; for him they seemed undoubtedly certain.(181)

428. He says:

These errors of the imagination necessarily resulted from the failure to explain the communication of the soul with the body and from ignorance of the subjective nature of the body. The soul was therefore accorded an extrasubjective nature, but one so tenuous that it escaped the senses. As we see, the whole of ancient philosophy followed the same road. Let us continue with our overview of the history of opinions, still following Fernel, who now describes the opinion of Alexander of Aphrodisias:(182)

Fernel, when describing Aristotle's opinion,(183) seeks to reconcile it with the previous opinions. He continues:

Fernel, bearing in mind the previous opinions, concludes very solemnly:

By 'spirit' Fernel understands an extremely subtle body as a vehicle for innate heat, because innate heat(184) cannot exist without a containing fluid to which it can adhere.(185)

These philosophers were unable to conceive the subjective nature whose phenomena they saw. They strove vainly to attribute this phenomena to extrasubjective nature which they made so subtle that it escaped the external senses and provided no extrasubjective experience. But at least they clearly understood that the phenomena of soul must be explained by something alien to extrasubjective experience, although they were unaware of what lay beyond this experience. Nor did they understand that the laws of the extrasubjective body, even the most subtle and totally evasive of the senses, are essentially the same, and that the body does not change nature with its size, because size, whether great or small, is purely and simply an accident.

Notes

(178) Cf. NE, [vol. 2, 806 ss.].

(179) Black is said to be the absence of colour. This is definitely true because colour means various sensations in the eye when struck by rays of light, or the aptitude of bodies to absorb some luminous rays and reflect others, or even the light rays themselves. In none of the three of these meanings can we say that black is colour. But is black simply the absence of light rays in such a way that the word is a pure negation? I do not think so. I hold that black is a feeling, and properly speaking is the fundamental feeling of the retina which, when stimulated by appropriate movements, displays its activity in colours. If the reader were to close his eyes lightly in a dark place so that no light penetrated and then concentrated his attention on observing whether he was conscious of any difference between the state of his eye devoid of all stimulation and that of one of his fingers, for example, relative to the feeling he experiences, he would notice, I think, a different feeling in both parts and will assign the feeling of black to the eye but never to the finger. It will be objected that this happens because he remembers the sensation of colours experienced by the eye and not by the finger. But I do not think this is the case. The difference between the feeling in the eye and in the finger would be imaginary. On the contrary, it seems to me there is a real difference of feeling which precludes completely any comparison with the previous state. Furthermore there is no reason why the pure absence of colour must give the feeling of black, rather than no feeling at all.

(180) Descartes stripped the soul of any power to act on the body: his disciple, Malebranche, invented the system of occasional causes; Leibniz, the system of pre-established harmony. In doing this, the three great men had glimpsed a beautiful truth which they were unable to describe and formulate. They had glimpsed that subjective and extrasubjective phenomena differed specifically. Desperate to find a nexus between the phenomena, they had recourse not only to gratuitous hypotheses but hypotheses that basically included several absurdities. The cause of their errors lay in their insufficient observation of nature. When internal observation or consciousness of what happens in us is scrupulously noted, it indicates the existence of a simple principle and an extended term in animal feeling. Once this FACTUAL truth has been discovered, all reasoning must cease and be satisfied with what it has found, if we wish to be disciples of nature. Now, this fact tells us that the simple principle and the extended terms form one single feeling in which the communication of the soul (principle) with the (extended) body is the most intimate and, I would say, the most physical imaginable.

(181) De naturali parte medicinae, bk. 4, c. 1 & 2.

(182) In Problematib.

(183) De animal. generat., bk. 2, c. 3.

(184) He then applies himself to showing that this innate heat is not elementary heat, but something with its own proper nature.

(185) This is his proof of the thesis: 'Simple heat, as a quality, cannot permeate a body or be diffused in it without some seat and means of motion, as indeed we perceive it to be given to the individual parts from the heart through the arteries. Consequently it was necessary, I think, for it to be carried by some spreading fluid. But there was no humour suitable and able to pervade the whole body with such speed. Consequently heat needed some very subtle, substantially free-flowing and consistently swift matter which by its warmth would be friendly and familiar to heat. Now, because air, or if you prefer ether, is like this, it would most fittingly serve as a support for heat. Air always burns like ether, and heat is perpetually present in it so that one cannot be divided from the other.' He also notes how Plato sometimes calls spirit materia calorifera [calorific matter]. De naturali parte medicinae, bk. 4, c. 2.