Chapter 14 (Part 2)

2054. Primal sense-experiences act as a lever for sensuous instinct, which they put in movement. I shall recall briefly the laws I have previously assigned to the activity of this instinct.
First law. - Given a sense-experience, sensuous instinct immediately goes into action and produces movements which help to increase pleasure or lessen pain. In both cases the sensuous instinct comes to the help of the life instinct, which produces pleasure, and struggles with the hostile power impeding it.

2055. Second law. - The quantity of the tendency or activity with which the sensuous instinct arises is equal to the intensity and, in general, to the quantity of the excited feeling whose vivacity is proportionate to the strength of the life instinct. But variations in the strength of the life instinct depend on the causes already mentioned and, in human beings in particular, on the affections of the intellective principle. We saw that great, rational fear produces fright, an animal passion, which weakens the forces of the life instinct. The degree of these forces again depends immediately on animal affections (fright, sadness, and so on), as animal affections can be the effect of movements aroused by the action of the sensuous instinct. This in turn has immense influence in strengthening or weakening the life instinct. The two instincts thus influence one another reciprocally. But whatever the causes rendering the life instinct stronger or weaker, it is certain that through its liveliness even the sense-experiences which it produces under the same stimuli are more or less strong and hence more or less active in arousing the sensuous instinct to action.

2056. This explains how weak, timorous, lymphatic and robust temperaments may all exist within a healthy state. It also explains the division of illnesses into acute and chronic. When the fundamental sense-experiences are thwarted, and sensitivity as a whole is sluggish, the sensuous instinct cannot act normally either for or against the machine. The instinct is unsuitable for producing the healthy movements which determine the secretions and excretions necessary either to dominate or expel the inimical potency. This is a chronic condition.

2057. Third law. - The operation of the sensuous instinct normally begins with a sense of disquietude because the movements it produces are not included in feeling. In its very first instant, therefore, this instinct is ignorant of the movements which increase its state of pleasure or lessen its state of pain. Consequently, it is uncertain, and attempts all possibilities before determining on a certain direction. During this uncertainty, when sensuous activity is exerting pressure on all sides, the instinct feels the kind of disquietude indicating a need for action, but without however immediately positing it.

2058. Fourth law. - The sensuous instinct always preserves the most pleasurable of all its possible states. Hence, if activity costs more energy or trouble than non- activity, the sensuous instinct ceases to act. There are many extremely important consequences of this condition, some of which are:

1. It is more difficult not to act when the impulse, that is, the intensity of the sensation, is greater. In this case, action constitutes a more pleasing and less troublesome state for the instinct than inertia, other circumstances being equal.

2. If the intensity of the sensation is diminished by passive habit, this in turn diminishes the impetus of the sensuous instinct. The active habit on the other hand facilitates and thus increases movement.

3. Because the force with which the sensuous instinct acts does not depend only on the intensity of the sense-experience, but on the relative degree of pleasure which the instinct finds in acting, its force of operation can diminish for other reasons, that is, for all those reasons which make action less pleasurable and troublesome. This explains to some extent the instinct's disease-capacity, that is, tolerance of remedies which would be intolerable to a healthy animal.

4. The quantity of movement effectively produced by the sensuous instinct depends to a great extent on organisation which either provides obstacles, or lessens its forces, or assists the propagation of motion (granted the disposition, mobile form and degree of life in the molecules).

2059. 5. Sometimes, when the disconcerted organisation places the sensuous instinct in such a miserable condition that it cannot move in any way without suffering more pain and disturbance than from an entire cessation of action, the instinct does in fact cease to act. This means that the animal dies almost spontaneously. In this case, although the organisation is not so extended that it cannot be brought to receive sense, the sensuous instinct no longer applies itself to producing the excitatory movements necessary for the conservation of the organisation itself, which is soon broken down and becomes unsuitable for excited, individual life.

2060. We can, therefore, conceive four principles of death.

1. The rational principle which, when seized by a supremely painful affection, cuts off all forces from the life instinct. As a result, disorganisation, although not present in the first instant, takes place very soon.

2. Matter which is disorganised through foreign forces and thus removed from the action of the life instinct.

3. The sensuous instinct which, by choosing to abstain from all action because it is more troublesome than inaction, ceases to produce the movements necessary for the maintenance of the organisation itself (cf. EHS, 691).

4. The sensuous instinct, which produces such precipitous movement that it ruins the organisation.

2061. [Fifth] law. - When no causes are present to impede the production of movement by the sensuous instinct, movements increase or diminish according to the degree of the sense- experiences. Although they increase or diminish in the entire machine, this effect is much more accentuated in certain localities in so far as 1. these sense-experiences are local and 2. the sensuous instinct finds that one or other of these things is more in harmony with the pleasurable state it is seeking. This explains local inflammations and other phenomena to which we shall return when we begin to consider the third element of the fundamental feeling, that is, its unity and harmony.

2062. We return now to the distinction between primal and second sense-experiences. I have already located the characteristic of primal senseexperiences in the fact that the life instinct which produces them is not yet modified by the action and products of the sensuous instinct. Consequently, these sense-experiences are the effect of the vital activity in its native state.

2063. Indeed, the sensuous instinct aroused by the primal sense-experiences produces some kind of new potencies with its action, that is, habit, the retentive faculty, affection and presentiment (or animal expectation) which is an affection resulting from several successive feelings united in the power of the synthetical force, as I said in the Anthropology. All these potencies are acquired activities, and properly speaking modifications and increments of the original animal faculties.

2064. Primal sense-experiences are, therefore, those produced by primal excitatory movements, that is, by movements not produced by previous sense-experiences, but by external stimuli and connatural internal stimuli. Another characteristic of primal sense-experiences is their singularity. The effect of several contemporaneous primal sense-experiences which are fused in a single affection is already a product of primal sense-experiences, not a primal experience itself.

2065. Nor should primal sense-experiences be confused with changes which can arise in the fundamental feeling of continuity. The former pertain to excited feeling. The fundamental feeling of continuity can be modified either because of the approach of new molecules or because they separate from the extended felt element. When new molecules approach, the following cases can be conceived:

1. These molecules already have an organisation similar to that of the living body to which they are united. - This would be the case in blood transfusion, or when a detached nose is replaced, or after an amputation when the stump is covered once more with skin, or when wounds heal, and so on.
Whenever molecules approach, we have to prescind from any consideration of concomitant painful or pleasurable sense- experiences produced by excitatory movements, and focus our attention only on the activity of the life instinct which continues the individuated feeling into the new particles. It is this operation alone which pertains to the class of primal alteration of the fundamental feeling of continuity of which we are speaking.

2066. The activity which renders feeling continuous with close, well-disposed molecules is conceived as spontaneous to the life instinct. However, the molecules cannot always approach perfectly (it is impossible, for example, to re-attach a part of a nose in such a way that vessels and filaments in both parts match exactly). The result is an accidental, complicated work on the part of the life instinct which completes what is lacking to the perfect matching and continuity of the parts. Granted this possibility, the addition of perfectly organised molecules will be useful or harmful to the zoic course in so far as the molecules are either superfluous to the machine's needs, or make up for lacking molecules.

Superfluity, for example, an over-abundance of blood, would alter the zoic course in several ways. These alterations would not, however, be related to continuity but to the excitation impeded or furthered by excess, and to animal unity.
2. The molecules are sufficiently organised to ensure that the life instinct, with its activity, adds the final modification which the molecules need for entering individual life. - This takes place in the digestion of all alimentary matter.

The function of nutrition is a course of successive actions of both the life and sensuous instincts which furnishes an element to the zoic course. When the organs are in a normal state and the food is appropriate, this entire series of actions of the two instincts is natural and pleasurable. But if some defect is present in the organs or in the quality or quantity of matter, inappropriate stimuli are present which retard domination by the life instinct. The result is a painful struggle and consequent movements, and so on, all of which alters the fundamental feeling of excitation.

After nutrition, the fundamental feeling of continuity is changed. This change is nothing more than the addition of several molecules to the living continuum. Again, this addition is either useful or harmful to the zoic course in so far as the added molecules either take the place of those which previously contributed to the natural perfection of the machine, or are superfluous to the needed replacement. For example, if some kind of fluid is overabundant or one solid develops out of proportion to others, we have two causes which normally alter the organisation and consequently the order of zoic movements. In the same way, if nutrition is imperfect, secretions do not fully receive the quality rendering them apt for life. The two prior effects upset excitation and animal unity; the third is a defect inherent to the element of continuity because the molecules inserted in the body are not fully dominated by the life instinct and thus become inappropriate stimuli.

2067. 3. Solid matter is not convertible into fluid by the vital forces nor assimilated by the living body. - This kind of solid matter normally alters the zoic course through the movement it produces in the body with its mechanical impulse.

2068. 4. We are dealing with matter whose chemical forces act on the living body with power greater than that of the vital principle. - Such forces tend to disorganise the body by withdrawing it from the influence of the vital principle. This is seen more easily in the case of body fluids rather than solids. Poisons which decompose the blood, and so on, are one example.(101)

Matter, acting on the material forces of the living body, tends to provide the molecules with a different organisation, position and attitude from that required by the animal and from that which the vital principle labours to give them. The effect, destruction of the vital organisation, cannot be impeded by the life instinct alone. Sometimes, however, it can be conquered by the sensuous instinct which comes to the assistance of the life instinct. This is the case with fevers which have their origin in miasmas, or pox, or with any illnesses indicating the introduction of diseased matter into the human body. After a time, this matter ceases to exercise its harmful action either because it is excreted from the body as pus or in some way by the aroused actions of the sensuous instinct, or because it is elaborated, recomposed and made suitable for receiving the domination of life by similar aroused actions.

It can also be neutralised by the action of some other matter introduced into the body with it. Examples are antidotes for poisons; ammonia, say, which is used for viper poison. In these cases, the zoic course undergoes serious alterations although, during the struggle, it is not the alteration to the fundamental feeling of continuity which changes it but the changes to the zoic course which come about through the alteration received by the fundamental feeling of excitation, and through partial sense-experiences.

2069. If we consider the case in which molecules separate themselves from the living body, we find that this occurs
1. through various excretions;
2. through violent separation of one part.

2070. Both these cases modify the zoic course.
Many excretions are natural and the inevitable effect of movements pertaining to the zoic course itself. These are not painful sense-experiences, but simply reduce the fundamental feeling of continuity. But if they are not replaced, the fundamental feeling of continuity cannot diminish without lessening the fundamental feeling of excitation because the lost molecules reduce the stimuli in the body. Excessive loss leads to debilitating, excessive alteration in the organism of the solids. Fluids which diminish excessively are no longer effective in stimulating the solid to movements which complete the solid's natural functions. In addition to insufficient stimulation and excitation, solids perish through lack of nutrition. They shrink and dry up. In a word, the organism necessary to complete perfection of the functions themselves is altered. Nothing therefore prevents our calling 'counter-stimulants' all secretions and body losses, provided that counter-stimulants are not conceived through the imagination as a positive potency opposed to stimulus.

2071. The loss of a member, by lessening the fundamental feeling of continuity, modifies the zoic course. This modification must however be attributed far more to the imperfection remaining in the organism and damaging the fundamental feeling of excitation than to diminution of the extended felt element.

2072. Granted this, we now come to consider variations in the primal sense-experiences which, taken as a whole, constitute the fundamental feeling of excitation in its constant, typical part.
These sense-experiences vary

1. According to the variety of action in the intellective principle which acts on the animal part by means of affection and will. - The fundamental feeling of excitation is principally altered by affection. All rational affections which have good as their object increase the fundamental feeling of excitation; those which have evil as their object lessen it.

2073. More particular research into the influence of this rational affection on animality would first require some determination of the different characteristics of excitation produced by rational affection which has a physical good or evil as its object. Further research would then have to be carried out on affection which has intellectual good or evil (knowledge) as its object, and finally on that which has moral good or evil as its object. After establishing this categoric difference, we would need to distinguish different ways in which rational affections can be related to the same categoric object, and find the kind of excitation produced by each of these relationships. Moreover, we would need to classify the good or bad objects contained in each category, and recognise and characterise the exciting and depressant property of each class.

2074. We cannot, however, pursue this research further. I simply observe that rational affections concerned with good can be called stimulants, and those concerned with evil, counter-stimulants (if indeed we wish to give this word a meaning which indicates a cause suitable for directly diminishing the activity of the life instinct).

2. According to varying organisation. - The excitation of the fundamental feeling depends on habitual, intestine movements of the body. Consequently, the varying direction, speed, multitude of movements, etc., which the organisation imparts to these movements influence the change of corresponding sense-experiences and with them the whole zoic course. For example, nutrients, which also change the zoic course by modifying the organisation, have to be considered at two stages during alimentation. At the first stage, they are external, natural, appropriate and pleasant stimulants. At the second, they are already assimilated to the human body and enlivened. Then, partly changed into fluid, they become internal stimuli; partly changed into solids, they constitute the part of the organism on which stimuli principally act.

2075. 3. According to the varying quantity and quality of the stimuli. - With the increase of interior and exterior stimuli, the system of sense-experiences and consequent movements must change. I say 'they must change'; I do not say 'they must increase'. It is true generally speaking that movements and sense-experiences increase as stimulus increases, but only up to a certain point. Once that point has been passed, excessive stimulus blunts and numbs the part which remains inactive. This is another reason for considering the appropriateness, rather than the mere quantity of stimulus.

2076. This, I think, explains why symptoms so often deceive doctors who interpret them too confidently, or in isolation, or according to the miserable rules offered in a system dependent on quantity. Often lack of strength and lowering of the pulse seem to indicate weakness, although they may well be a sign of excessive stimulus impeding the vital action or restricting it to the centre.

The numbness produced in the fibre by excessive stimulus is, it seems to me, one of the most important facts to be considered by medicine, especially if we pay attention to the effects which can follow it in the zoic course. If accelerated movements in the interior of the human body produce greater stimuli, and if these movements slow down when the organs, numbed by excessive stimulus, are unsuitable for greater action, we have two causes operating simultaneously in opposite senses. We have an excess of stimulus which dulls the organs and, as a consequence of this dullness, diminution in the reproduction of the stimulus as though nature were seeking in this way to restore the balance. We still have to see, therefore, whether the total of increased and diminished stimuli provides a general increase or diminution. In other words, we have to see whether the internal stimuli can be more diminished by the inaction of the organs than the increase of external stimuli whose excess has produced the torpor. In this case, the total effect of genuinely stimulating substances could result in a diminution of stimulus. This observation shows how difficult it is to determine the true nature and efficacy of remedies.

For example, I see that digitalis lessens the action of the heart and vessels, slows the circulation and makes one sleepy. But who can say if the effect produced by this plant depends, as some say, on its being a true counter-stimulant, or rather on its being an excessive stimulant. Consider, for instant, how digitalis produces different effects when the stomach is irritated. It accelerates the pulse, increases secretions and causes vertigo or muzziness in the head. Surely it is impossible to doubt that digitalis, when it finds greater resistance in superior, vital force and cannot produce its dulling effect, manifests its true stimulating property.

The same is true if digitalis is given in large doses. It shows its stimulating quality, surely, by producing in these circumstances the exultation, the irritation which resists and hence excludes torpor. But, these doubts not withstanding, it seems that the general fact is certain: a strong stimulus dulls and numbs the vital movements which, in their turn, lessen the reproduction or action of internal stimuli. Consequently, doctors will always have to give great consideration to the above-mentioned calculation about the final, overall effect of the two series of excessive and diminishing stimuli. In special cases, the second relationship, according to which the second series can diminish when the first increases, will always be worthy of investigation. Nor is it absurd to conceive the possibility that effective diminution of stimulus may be obtained through a remedy which is of its nature a stimulant. All this will show how impossible it is to prove infallibly that diminution of excitation in a sick person as a consequence of some remedy means that the remedy is of its nature more a counter-stimulant or depressant than a stimulant. But this is the easy conclusion reached by those who do not reflect on the complicated series of causes and effects which in the zoic course intermingle and modify one another.(102)

2077. From what has been said, we can conclude that
1. the fundamental feeling of excitation can be normal and pleasing, or abnormal and painful;
2. the same feeling, normal or abnormal, can vary in degree according to the varying degree of excitation;
3. it is not the varying degree of excitation which makes the animal healthy or sick. These two states are constituted by the normality or abnormality of the excitation;
4. the greater the excitation, provided that it is normal, the greater the well-being of the animal;
5. the greatest measure of excitation depends in the human being on three causes: 1. the state of spirit or the action of the rational principle; 2. normal or abnormal organisation in its varying degrees of development and robustness; 3. the degree of quantity of external and internal stimuli;
6. every modification arising in each of these three causes completely changes, for good or bad, the zoic course.

2078. If excitation exceeds its maximum measure, it becomes inappropriate. This maximum measure is relative to the three conditions I have mentioned. Nevertheless, the following fact also shows that the quantity of excitation is unable to constitute the characteristics of illness. In more robust people, illnesses become more violent; in weak people whose temperament is placid and lymphatic, they take a milder, more benign character. Nevertheless, we have to affirm that a strong state is better than a weak state. What happens is this. If the first of the two states is formed by stronger and more excited vital actions, and the excitation then loses its normal form, the zoic course, which retains the same impetus, impels the sick person to more serious illness. Hence robustness and greater excitation, which are admirable in a state of health, become so harmful in illness that doctors sometimes confuse them with the illness itself. Indeed, such confusion is easy because the normal flow, which is more active, produces even greater stimuli. Consequently, we nearly always find excessive excitation in the illnesses afflicting robust people. On the other hand, doctors do not err in cases of this kind if they try to deprive the machine of its natural, appropriate forces which, because of their deviation, only increase the illness.
Rasori acknowledges the presence, in epidemic fevers such as measles, etc., of a harmful irritating matter in the human body. He advises a depressant cure, but wants it to be moderate. He says:

I am not really sure whether these words are coherent with the system proposed by this illustrious doctor. In all illnesses resulting from excessive excitation, he conceives the cure as a simple diminution of this excitation without admitting any essential difference between the different counter-stimulants. This should mean that the very presence of the unhealthy, stimulating matter could be rendered harmless directly with a dose of counter- stimulants equal in effect, but in a contrary sense. The fact is that depressant remedies, which are so useful in the treatment of such diseases, seem only to bring about lesser vehemence in the operations of the zoic course, as he himself confesses. But this vehemence does not constitute the essence of the disease, which consists in the abnormality or disorder of alternating movements. The disorder is particularly harmful when it shares in the natural liveliness proper to movements and vital sense- experiences.

2079. We now have to pass from consideration of sense-experiences to the faculty itself of feeling, and note the variations of the faculty in relationship to the zoic course which it determines. The fundamental feeling is an act, the first act of feeling. From this point of view, it is not a simple faculty.

If we wished to conceive some faculty anterior to the fundamental feeling, which we may call 'the faculty of the fundamental feeling', we would have only a mental ens, a mental fiction. In fact, nothing exists in a subject before a first act, not even a faculty taken in an active sense. Prior to the fundamental feeling not even the animal exists. If, on the other hand, we understand as the faculty of this feeling, the life instinct which produces the vital activity, fundamental feeling, we do not have a faculty anterior to the fundamental feeling, but consider, in the fundamental feeling, the force constituting the feeling, the substance of the soul. By faculty of feeling, therefore, I do not understand something prior to the fundamental feeling, but only the active potency which enables beings to feel in a way different from that of the fundamental feeling.

2080. By sense-experience, I understand a species of modification of the fundamental feeling but not every species. Modifications of the feeling of continuity are not sense-experiences. No matter what attention we give to them, it is extremely difficult to observe and become aware of them. Even an increase or decrease of the force of life instinct is not a sense-experience, nor is it attained by human thought which remains unconscious of it. In a word, sense-experiences pertain to excited feeling, of which they are modifications.(104) Sensitivity takes various special forms. It permits various degrees in each form. All this varies the condition of the animal, that is, the progress of the zoic course.

What is the cause of the various specific forms and various degrees of animal sensitivity? If we want to find the final reason, that is, the truly formal reason for these wonderful variations in species and degree, we have to consider the intimate nature of the fundamental feeling, which is modified by sense-experiences. The explanation of the modifications to which a subject is susceptible can be found only in the nature of that subject. Modifying a subject means that the same subject, when existing in different modes, preserves its own identity in all of them. If we wish to go further and ask why a subject is able to exist in different modes, we can give no other reason than that is its nature.

If we knew positively the nature of a subject, we would also know a priori all the modifications of which it is susceptible. In other words, we could deduce them solely from the concept of its nature. But the nature of the fundamental feeling is unknown to us in itself, as we can see by considering that the fundamental feeling of continuity escapes our intellective attention. Excitation, however, is only an act of the feeling of continuity. If, therefore, the fundamental feeling of continuity escapes our awareness, the nature of the feeling of excitation also remains unknown. We can only deduce its modes, forms and degrees a posteriori from what we know of the senseexperiences which fall within our awareness.

We are, however, constrained to affirm from our meditation on the facts that all these different forms of feeling depend on the intimate nature of the sensitive principle, that is, the substance of the soul. It is a fact that the same, identical feeling has various modes of being; it is another fact that these modes change with no loss of identity to the feeling; it is a third fact that what we call sense-experience is only a mode of feeling; it is a fourth fact that in feeling there is an element of passivity of which the subject is the sensitive principle; it is a fifth fact that an element of activity, whose subject is also the sensitive principle itself, is also present in feeling. Various forms of feeling, therefore, depend upon the special nature of the passivity and activity of the principle. But a principle contains virtually within itself all the acts and modes to which it is susceptible. The sensitive principle, therefore, contains virtually all the different forms of sense-experiences which are extricated, not re-created when they enter our consciousness. In other words, what was implicit becomes explicit; feeling does not change its being, but its mode of being.

2081. We still have to see what occasions or conditions lead to the unfolding of sense-experience. Reduced to a general formula, the fact we must keep before us is the following: 'Feeling adapts itself in the most pleasurable way possible.' But what is it that places a limit to the possibility of various ways of adaptation? - Our answer is to be found in what we have already stated: the proper nature of the fundamental feeling. A priori, we have nothing more to say. We must have recourse to experience to know this limit in some way, and to understand the nature of the most pleasing attitude feeling can take, granted certain conditions.

Since experience attests that the nature of the sensitive principle includes an element of passivity relative to an extrasubjective ens, it is clear that this extrasubjective ens and its way of operating must be one of the conditions on which the most pleasurable state of the animal depends. The feeling, therefore, must find its most pleasurable attitude in one mode rather than another when the extrasubjective ens acts on it in one mode rather than another.

2082. There is nothing contradictory, therefore, if different forms of sensitivity depend on different organisation of the organs in such a way that the reason why the eye is susceptible of coloured sense-experiences, the ear of sound sense-experiences, the nostrils of odorous sense-experiences, the taste of palatable sense-experiences, the stomach, intestines, and so on, of sense-experiences proper to their own form, is simply the different action of the body on the sensitive principle. This in turn depends on the different organisation of the organ itself, although the sensitive principle of itself has the same act under every organisation. This can be confirmed also by the observation of physiologists who tell us that every stimulated nerve gives only a sense-experience proper to itself. Thus the olfactory nerve provides only sensations of odour, the optic nerve only of colours, and so on. If the sensitive principle is excited by movements proper to the olfactory nerve, it feels pleasurable odours. If these movements then attempt to disturb natural excitation, a manifest struggle arises with displeasing odours.(105) What is properly displeasing to the optic sense is poor sight or the distress caused by excessive light.

2083. There is no doubt, therefore, that the spirit would feel wherever appropriate nerves were present. It could see with its feet if there were in the feet an organated nerve like the optic nerve; it could hear with the hand if there were an acoustic nerve in the hand, and so on. The spirit could even see in a hundred parts of the body, as Argus claimed he could, if there were a hundred eyes in the body. The same can be said about every other sense-experience which is in one place rather than another, or in a single place rather than in many. This would come about not because of any diversity in sensitivity or in the faculty of the sentient principle, but as a result of the diversity of organisation which obliges sensitivity to be determined in one mode rather than another by what is more pleasing in these circumstances. If an organ constructed in this way is lacking, the relative form of sense-experience ceases.(106) Morgagni, Fatner, Loder and Valentin describe how they found olfactory nerves lacking in people who had never experienced smell.

2084. Now it is certain that every special form of sensitivity has the power to change the series of vital actions which make up the zoic course. There is, in fact, a determined species of movements, initiated by the sensuous instinct, which correspond to every species of sense-experience.

2085. If we go now to the different degrees of sensitivity, we find that this diversity is reduced 1. to a particular disposition of the sentient principle; 2. to a particular disposition of the animated matter which determines the principle to one disposition rather than another.

2086. Experience shows, relative to this particular disposition of matter, that in certain bodies finer tissue and more subtly organated members are present. Those individuals whose flesh and organs have finer tissue show they possess a more delicate, prompt, lively and powerful sensitivity.

2087. The degree of action of the sensitive principle depends upon the various causes I have mentioned. The life instinct languishes or expands when the spirit is preoccupied with pain or diffused with joy. When the intellectual principle is immersed in the contemplation of an object, animality abandons some part of its own action because the subject, which is one, has a limited quantity of force. This cannot be used to any great extent in intellective operations without some loss to animal activity. Consequently, a person with a full stomach suffers from indigestion if he studies seriously. The same is true about all the discomfort suffered by studious people. But the degree of sensitivity depends above all on the sensuous instinct which exercises the greatest influence on the life instinct, which in turn influences the sensuous instinct. Sensitivity is increased by the sensuous instinct:

1. Through force of active habit.
2. Through retention of pleasures previously enjoyed. The retentive faculty, which contains an accumulation of already experienced, pleasurable movements, has more force to move the sensuous instinct than a new, actual pleasure has. We can see, therefore, that imagined pleasure often exercises greater force on human beings than real pleasure.

2088. The same principle provides the explanation for many hedonistic phenomena. Why, for example, is the greatest intensity of an awaited pleasure experienced at the moment the pleasure is encountered, that is, at the moment it arises, rather than when it has already arisen? The answer depends to a great extent on the way pleasure is united with movement. In other words, pleasure is principally actuated in the act of movement, which is gradually succeeded by rest. Nevertheless, this is not sufficient to explain the intensity of greater delight which is found in the first act in which we possess the desired pleasure. Here, the intensity depends upon imaginary expectation arising from the retentive faculty which retains the many pleasurable movements already experienced.

The imaginary expectation places the sensuous instinct in an extraordinary orgastic state, in painful disquiet, arousing the kind of impatience which seeks repetition of the pleasure that has accumulated from all anterior pleasures in the apprehensive faculty. The sensuous instinct, already moved violently by the retentive faculty in its first encounter with the pleasure, then finds its greatest enjoyment not only through enhanced desire, but through the satisfaction which follows its burning longing and puts the instinct at rest, a rest obtained at the moment in which it sees its way open to the pleasure it has desired. In other words, when the fierce urge of that appetite has been placated satisfactorily, all that remains is the real pleasure which is considerably less than it appeared to the desire, and consequently less suitable for moving the life instinct.

2089. This also explains the other phenomenon expressed so well in holy Scripture: 'Stolen water is sweet, and bread eaten in secret is pleasant',(107) as well as the popular proverb: 'Absence makes the heart grow fonder.' Something forbidden, or difficult to obtain, or desired for a long time, renders the sensuous instinct restless, more active and almost constantly vibrant. Again pleasure, when unexpected and snatched at because time presses or through fear that the precious instant will evaporate, becomes more lively, more intense, and possesses a new character all its own. In other words, the more restless and preoccupied the sensuous instinct is, the more it provokes quicker and more violent sparks and movements in the nervous fibres whose greater rapidity is the principal source of the intensity of sensation. Thus we see that a person broken by pleasures holds his sensuous instinct as it were habitually under tension in expectation of their repetition. The nerves themselves are stretched out towards all the oscillating and, as it were, scintillating sensuous stimuli which form a prelude and initiation to the desired, awaited sensations.

Nevertheless, it is also true that the physical condition of these nerves shows them to be blunter than those in a moderate person because nerves which are always taut are not susceptible of great movements (which imply successive deceleration and tension) and because the novelty of pleasure becomes ever less. But if real pleasure lessens in a person who is a slave to voluptuous passions, anguished desire increases in the spirit. This desire has no end(108) and constantly serves as a lever to the sensuous instinct. However, it remains true that the state of the sensuous instinct in the voluptuous person has greater mobility and activity. This enables the life instinct to be more active and ready in producing pleasant sense-experiences.

2090. 3. Through the reproduction of constant, internal stimuli produced by the sensuous instinct. This explains greater intensity in the sense-experiences, and the very causes which render the life instinct more powerful.

Hence:

We can thus explain how our sensories become more acute with frequent use. For example, a diamond-cutter's sight is sharpened with use. It seems that the sensory faculty of the eye is increased not only through the outreach of the nervous extremities which search for stimulus and present more open pupils to it, but also as a result of the greater influx of blood which with its stimulation enlivens the part, rendering it more sensory. In fact, if the eye is used beyond a certain limit, inflammation occurs. This shows that fluids are involved. Another proof of this involvement is the enlargement and development of the more-used parts of the body. This happens because greater nourishment flows to these parts.

2091. As a result of the impetus, excess and alteration of crasis, the stimuli which the sensuous instinct brings to the special parts of the human body may confuse the organisation and tend to destroy it. If so, a struggle begins causing pain in these parts. The fundamental feeling of the afflicted parts is not normally very painful if the difficulty of the organic process and the disordered intestine movements do not exceed certain limits. Nevertheless, the sensitivity to pain is great because only a slight touch is needed to provoke intense suffering.

This occurs in the case of inflammation which increases the volume of the part and consequently shows that fluid has flowed to it. Inflammation also reddens the afflicted part, indicating a greater influx of blood, and makes it painful to the touch if the inflammation is slight, and without being touched, painful if the inflammation is severe. As I said, this shows the struggle between the life instinct and matter, which is poorly disposed for its intended purpose.

The tendency of all inflammation to disorganise the inflamed part shows how poorly disposed matter is at that point. Congestion of the small vessels and deceleration of motion of the fluids leads to the same conclusion. Blood seems pushed out by a greater movement of the heart and arteries to the extreme, venous capillaries which, unable to tolerate the movement, must suffer so much pressure that they overflow or rupture;(110) the tiny nerves must be stimulated and irritated on all sides. The blood itself, heated by the orgasm in the arteries and as it were stagnant, tends to become disorganised, that is, to let the fibre separate, which then tends to consolidate and organate into new tissues and organs. At the same time, the grum and the serum tend to change into pus.

2092. Brachet describes how in 1811, while returning to the hospice at Bicêtre, he was met by the nurse in charge of the operating theatre who wanted him to look at an extraordinary development of his vision that had occurred during the morning. He saw very small objects at a great distance but did not feel ill. Five hours later, he felt a slight headache. After a few hours more, he experienced a lightning fit from which he died during the night. A deposit of various matter was found in his right optic thalamus. This had inflamed and irritated the part of the encephalon, the seat of vision. The great increase of visual sensitivity came, therefore, from the increased stimuli on his visual organ and probably also from the greater mobility acquired by the organ. A priest once told me that he seemed to be another man as a result of the clarity of mind and readiness of thought which had come over him, and as a result of the senses themselves which had become extraordinarily acute. He imagined that his new state was truly blessed. I immediately advised him to undergo a thorough bloodletting. He put this off for several days and went mad.

c) The sensuous instinct increases sensitivity by rendering the sensory fibre more mobile. - How do we explain this greater mobility? There is no doubt that when the organism is more perfect and greater flexibility is found in the tissues, and so on, the fibre must become more mobile. But equally organised fibres must also be rendered more mobile and ready to provide sensation by being subjected, as I said, to a greater quantity of internal, continuous stimuli. The case is analogous to that of a body which, when pressed in various places, moves more easily at every increase of pressure from one of the sides. Another example is that of weighing scales which move as soon as even the smallest weight disturbs their perfect equilibrium. Moreover, animal instinct is more awake, more alert and more ready to act when it is moved on all sides for good or bad. In this case, the fibres preserve the continual oscillation equal to a quantity of incipient sense-experiences, all of which have a tendency to enlarge and expand.

This and the preceding cause seem to explain fairly well the many phenomena resulting from different degrees and variations of sensitivity. This is true whether we are speaking of pleasant or unpleasant sense-experiences. For example, it seems to explain why the special sensitivity of taste becomes either sharper or less acute as the stomach suffers various kinds of inflammation. When some affection effects the pneumo-gastric nerves, or when it acts on the nervo-ganglia system, the organ of taste takes on a new condition for one of the following reasons: its intimate organisation is changed at certain points; new internal stimuli are applied as a result of disorder; it is rendered more mobile and oscillating. The modifications to which the organ of taste is subject as a result of uterine infections are extraordinary, whether we consider the capricious tastes of girls as they near puberty, or women whose periods are difficult, or who suffer other discomforts, or pregnant women. The explanation of increased activity in the phantasy during sleep and sleep-walking must be sought in the same causes.

2093. d) Finally the degree of sensitivity depends to a great extent on the various ways in which the animal instinct contributes with its activity in the production of some sense-experience or in the spontaneous movements necessary to produce a sense- experience. The life instinct does not lend itself to the production of a sense-experience unless omission is more troublesome than production. The sensuous instinct follows the same law relative to movements; it lends itself to their production only if this is more pleasant than not doing so. This is what I maintained relative to the extraordinary phenomenon of disease capability. Giovanni Rasori's experiment is well-known. He administered tiny doses of cream of tartar, followed by a dram and then several more drams in the course of twenty-four hours, and even ounces in the course of an illness, without producing vomit, or producing it only rarely, and without increasing stools, or only to a slight degree. All this was done without signs of greater perspiration than the nature and length of the illness normally entailed. He carried out similar daring experiments with all kinds of antimony preparations: emetics, nitrate and the most drastic purges.

He seems to have met with some kind of contradiction. This disease capability did not appear in any illnesses except those called sthenic (because they are characterised by an excess of stimulus). But if greater excitation is present in these illnesses, why are they almost insensible and resistant to the action of strong remedies? The explanation lies, I think, in the law I indicted: 'Animal instinct (life or sensuous) does not lend itself to action as a consequence of stimuli except to the extent that its co-operation is more pleasant or less unpleasant than its non-co-operation.' It is a mistake, therefore, to believe that 'the quantity of action of animal instinct increases or decreases in simple direct proportion to the quantity of stimuli.'

2094. We have to distinguish 1. the quantity of stimuli; 2. the quantity of excitation pertaining to the fundamental feeling; and 3. the quantity of action of the animal instinct, whether life or sensuous. As I said, the quantity of action of the animal instinct is not proportionate to the quantity of stimuli but to the already indicated regulatory law of its activity.

We can now ask other very important questions:

1. 'Does excitation exist in exact proportion to stimuli?' I think not, for the same reason.

2. 'Is the quantity of action of the instinct in so far as it produces a sense-experience, or animal movement, exactly proportioned to the quantity of excitation pertaining to the fundamental feeling?' Once more, I think we have to answer in the negative. It is not contradictory to think that animality may find it more pleasant to allow itself to be excited or at least less troublesome to suffer this than to separate itself from the stimulus. Again, when we are dealing with the passage to action of the instinct producing a sense-experience or movement, animality may find that resistance or non-cooperation in the production of the movement is more pleasant or less disturbing.

2095. 3. 'Is the quantity of action of the sensuous instinct, that is, the quantity of motion it produces, in exact proportion to the quantity of action of the life instinct, that is, in proportion to the quantity of sense-experience or sense-experiences produced by the life instinct?' Again, we have to say, and for a similar reason, that this is not the case, although it remains true that the sense-experience is the principle of a consequent animal movement.(111)

2096. We return now to the general principle and repeat what has already been said: 1. 'the degree of sensitivity depends principally on the laws of activity proper to the animal instinct', and 2. the phenomena of sensitivity cannot be explained simply by measuring the stimuli and exterior forces which act on the sensitive principle as if this principle were solely passive and not active, not endowed with its own laws determining its operation.

The more this truth is considered, the more deeply we understand all animal phenomena:

1. Why does a stronger sensation eliminate a weaker one? Why, for example, does our seeing the sun impede our vision of stars? - This must, no doubt, be attributed in part to mechanico-animal action which makes all the tiny fibres of the optic nerve oscillate in the same way and arouses a uniform sensation in which the partial sense-experience of the stars is rooted. This, however, does not fully explain why the light of the stars, which continues to make its mark on certain tiny fibres of the retina, causes no further sensation when the retina is struck by the stronger action of the sun. Rather we have to say, I think, that the tiny fibres struck by the light of the sun no longer receive movement from the diminutive ray of a star because sensitive activity is occupied in seconding the action of the greater stimulus. It is true that several causes, amongst them the mechanical law that a greater motion resists a very weak force which tends to modify it, concur in producing this phenomenon. Where a greater quantity of motion is present, there is more force to resist the change of direction or rhythm.

2097. 2. Why do the forces of the animal instinct resist chemical, physical and mechanical forces tending to break up the extremely complicated and corruptible machine of the animal body? - This is explained by the activity intrinsic to the soul as a result of which animal instinct impedes the action of gastric juices by using them to dissolve food and probably by impeding their dissolvent action from harming the stomach. On the other hand, there seems no doubt that in a corpse, the stomach is sometimes eaten up immediately after death through the action of such juices, which is no longer impeded by the action of the vital principle.(112)

Notes

(101) Flandin, in a paper read at the Academy of Sciences of Paris, 20th November 1844, deals with lead poisoning and claims that the locality of the poisonous agents of a metallic nature should be sought not in the blood, but in certain organs, such as the intestines, lungs, and above all liver where they accumulate after being brought through the vein valve. Poison can be received not only in the stomach, but introduced through skin absorption, and carried to the digestive tracts by subcutaneous vessels. According to Flandin, this explains the colic experienced by people who handle lead.

(102) Using the word counter-stimulant to signify not the nature of the remedy and its efficacy, but the overall effect, of which the remedy is only an occasion (the cause is the vital condition of the sick person), would mean giving the word a third, and improper, meaning. At most, we could call this effect an indirect counter-stimulant.

(103) Storia della febbre petecchiale di Genova negli anni 1799 e 1800, ecc. (Milan, 1806).

(104) Excitation can only arise if there is an appropriate organisation susceptible not only to division and addition of parts, which is the property of every corporeal continuum resulting from several elements, but to instinctive movement of molecules which remain in contact. This explains why only some parts of the body are sensory, although all are probably felt. For example, the epidermis, which can certainly be felt as the term of our fundamental feeling, does not provide any sense-experience under external stimulus because it totally lacks nerves and vessels. This explains in a word why nerves alone are seen as sensory, properly speaking. Only the nerves have the organisation necessary to be animated and felt without movement, and to receive excitatory movements and consequently sense-experiences.

(105) Cullerier and Maingault noted how the arachnoid was ossified in various places in a man who always experienced unpleasant smells. They also noticed suppurating cysts situated halfway through the cerebral hemisphere. Valentin, when cutting the nerves and olfactory ganglia of rabbits, noticed that the animals did not lose their desire for food, moved with the same agility as before and followed the instincts of healthy animals. Moreover, during the operation, they gave no sign of pain. In the same way, the optic nerve when irritated or cut, is insensible to common pain although the irritation produces light and coloured sense-experiences in it. These experiences are obscured if the organ suffers. The fact that there are almost no displeasing sensations of sight must be attributed, I think, to the extreme delicacy of its organisation and to the low level of power that the sensitive principle has in resisting its destruction. If some external agent stimulates it, sight either receives suitable excitation or begins to disorganate. The same must be said of the acoustic nerve in which, however, displeasing or painful sounds can occur; for instance, excessively sharp noises which disturb the natural excitation of such sense-experience.

(106) For the same reason, sense-experiences or relative feelings are more perfect when organs are better formed and developed. There is no doubt that greater development of the heart, for example, renders it more capable of feelings analogous to benevolence, charity and so on.

(107) Prov 11: 17.

(108) Cf. Society and its Purpose, 634-799.

(109) Irritation of the brain increases the sensitivity of the retina to the point where every ray of light becomes troublesome. The same happens in inflammation of the brain until fluids overflow with consequent paralysis of functions. In such cases, the life instinct is in extraordinary movement through its struggle with troublesome stimuli. Its increased activity serves to assist the tremor in the optic nerve which follows the sense-experience. Increase of activity results in the life instinct from its struggle with a hostile stimulus, and sometimes goes so far as to render irregular, but simultaneously more active, the function of the sensory nerves at the site of the struggle. This, however, does not occur if the activity is increased as a result of some welcome cause. We see, therefore, why maniacs and hypochondriacs are subject to optical illusions, or rather phantasy visions, or a mixture of the two. The same can be said about hearing, smell, touch and taste and in general about every kind of feeling, whether it consists in shaped or non-shaped feelings. Irritation of the brain, inflammation of the same organ or of the meninges and certain hypochondriac or manic affections provoke the sensitivity of these organs without limit and produce aberrations and sensitive illusions.

(110) Water expansion is found in dropsy, and blood expansion in fits, and so on.

(111) Note, too, that several contemporaneous sense-experiences can compel the sensuous instinct to contrary motions. In this case, movements are impeded. The same is true if sense-experiences considered as impelling forces collide only in part. Here the composition of motion must arise analogously to that which occurs when several mechanical forces are applied contemporaneously and in several directions to a body.

(112) Cf. the cases mentioned in Giovanni Rasori's Teoria della Flogosi, bk. 2, chap. 21. Many others could be mentioned.