The Sensibility of the SOUL ever Propor­tionate to that of the ORGANS.

There is a constant relation between the sensibility of the soul and that of the body, a determinate invariable relation.

Is the body endued with great sensibili­ty? The soul is so likewise: does it pos­sess but little of it? The soul ever pos­sesses it in the same degree.

The cause of this phenomenon is very simple.

[Page 101]However sensible the soul may be in it­self, the measure of that sensibility is un­discoverable by us, and is, in fact, wholly obliterated, even supposing the mind to have been pre-existent to the body, and that all its faculties were active before its union with matter: for the soul being once united to corporeal organs, there re­mains not the least vestige of its former state, every thing is forgotten. When united^*, the soul receives no sensations but by the body; like a sheet of white paper, whereon objects are represented after hav­ing passed through different intervening mediums, the soul receives its sensations by the organs of sense; its sensations there­fore are founded on impressions made on the body. But as the sensibility of the soul is a purely passive faculty, the different degrees of which are not known to us by any immediate method, and as the sensa­tions of the soul are all founded on those of the body; the vivacity of the sensations of the soul therefore depends on that of the sensations of the body. The sensibi­lity of these two substances must be equal.

[Page 102]Thus the degree of the sensibility of the soul depends on purely physical causes^*.

Why the Sensibility of the SOUL appears more powerful than the Sensibility of the BODY.

The sensibility of the soul is ever pro­portionate to that of the body, and the sensations are ever more strong at the in­stant they are received from the object, than when remitted from the memory^†. Hence it appears, that the most powerful artificial pleasures, the most lively paint­ings of the imagination, must necessarily be weaker than the impressions of the senses. However, when we compare the representations of fancy with those of na­ture, the brilliant paintings of love in the Adonis of Marini, with the merely physi­cal pleasures of that passion, we are much more strongly affected by the former than by the latter.

Whence arises this phenomenon? It is not that the sensibility of the soul is more strong than that of our organs, as might be inferred from these examples; but that [Page 103]the senses, in their enjoyment, being ever confined to their objects, can neither add to, nor take from them; whilst the ima­gination being free in the choice of its colours and its lineaments, incessantly passes from object to object, selecting that which is most brilliant, and most en­gaging, and from thence forms its images, as the bee its honey from the most delicious parts of flowers. The lineaments which are dispersed in sensual enjoyments, are col­lected, or rather concentrated in our ima­ginary pleasures, and acquire force from this concentration, as the rays of light collected in the focus of a mirror.

The paintings of imagination must therefore appear more powerful than the pleasures of the senses; although they re­ceive their whole force from the sensations of the body.

Why MAN is more sensible to Pain than Pleasure.

Painful sensations affect us incompara­bly more strongly than the agreeable; for violent pain destroys all sensations of plea­sure, but the most powerful sensation of pleasure cannot silence a strong sensation of pain.

[Page 104]However surprising this phenomenon may appear, it is not difficult to assign the cause of it.

Notwithstanding we are ignorant of the mechanism of the sensations, it is however certain, that their force is ever propor­tionate to the affection of the nervous fi­bres of which their organs are formed. In the agreeable sensations, these fibres are slightly affected; it may be said, that objects of pleasure pass only gently over them; whilst, in painful sensations, the same fibres are violently compressed, are ever rendered extremely tense and often broken.

Hence Man is less sensible to pleasure than pain; hence more strongly affected by the representation of Tartarus than by that of Elysium; hence the attraction of pleasure, the pleasingness of hope, always yield to the fear of torment and to the hor­ror of despair.

Why the Character of the SOUL is ever con­gruous to the State of the BODY.

There is a constant relation between the disposition or humour of Man, and the constitution of the corporeal organs.

[Page 105]Is the body affected with disease? The soul is sad Is the body in health? The soul is gay. Is the former in vigour? The latter is vivacious. Is that Ianguid? This is so too.

Sadness, gaiety, vivacity, languor, these dispositions, these sentiments, are experi­enced by the soul often when it is ignorant of their subject, ignorant even of their source. Like two harmonic machines, the soul constantly corresponds to the state of the body; the same phenomenon is ob­served at all times and in all places: the light does not more regularly follow the revolutions of the sun, than the soul the revolutions of the body.

Let us explain this phenomenon.

Although the sensations be not the cause of the passions, and although no mecha­nism whatever can produce in the heart a sentiment of sadness or of joy, it is ne­vertheless a law of nature, that when some particular sensation is received, some particular sentiment should arise in the soul; that^* pleasure should excite joy, and pain sadness.

[Page 106]Pleasure and pain spring from three different sources,

From external objects, by the senses.

From ideas, by thought.

From the internal parts of the body, by the general organs of feeling.

The agreeable and painful sensations which arise from the two first of these sources, are momentary; because the senses are not always affected, nor is the under­standing constantly in exercise: but the soul constantly receives sensations from the third source, if it be only that of the state of the body.

Joy and sadness, sentiments which have an immediate relation to agreeable and painful sensations, must therefore prevail in the soul in proportion as the one or the other of these sensations results from the dispo­sition of our organs.

The impressions of pleasure and pain, which we receive from the two first sources, are the cause of those transient fits of ex­ultation and sadness, which we so fre­quently experience, whose subject is ever known; those, we receive from the last, are the cause of that gaiety and sadness with which we are at all times more or less [Page 107]affected, frequently imperceptibly to our­selves, but much oftener without our knowing their principle: these form the basis of the humour of Man.

Whilst the body is in health, whilst all the functions are perfectly performed, and the fluids circulate with freedom and ease, this motion of the fluids produces on the plexus nervosi, which envelope the vessels, an agreeable sensation, a slight and vague emotion, more easily selt than described: this sensation passes into the soul by the nerves: hence joy, which springs from pleasure and incessantly accompanies it, must necessary arise therein together with this agreeable sensation. Thus gaiety and good humour are necessary attendants on health.

On the contrary, are the functions of the animal machine disordered? Are our fluids too dense, too acrid, in too large or too small a quantity? Is their circulation violent or difficult? The disorder within, produces in the soul a disagreeable sensa­tion, ever accompanied with sadness.

When all the functions of the animal machine are easily performed, Man is gay; [Page 108]when with difficulty, he is melancholy and sad.

When an easy or irregular performance of the functions is the natural state of the body, we are gay or sad by constitution. But as easy circulation results from the equilibrium between our fluids and solids; as this equilibrium may be easily destroy­ed in a machine so complex and so feeble as the human body, incessantly exposed to shocks from external objects, from the impulse of fluids penetrating it in every part, often so pernicious in their nature, and almost always with so little proportion to its delicacy, it may be easily conceived, that the state which produces gaiety, must seldom exist; but that which produces sadness, very often.

That voluptuous sensation, which arises from the easy motion of the organs, is likewise much more restrained than the disagreeable ensation which springs from a defect in their harmony. The former va­ries very little, because one cause only pro­duces it; the latter, on the contrary^*, is [Page 109]of different kinds, and each kind is dif­ferently diversified. Thus the gay cha­racter is ever uniform, whilst the melan­choly humour has as many gradations, as are found between the slightest and deep­est melancholy.

Although the voluptuous sensation, pro­duced by the perfect state of the functions of the body, be single in its kind, it has however its gradations. As this equili­brium between the solids and fluids is more or less perfect, the agreeable sensa­tion which results from it is more or less powerful, and the gaiety of temper more or less apparent.

The sensations therefore of pleasure or pain have their different degrees; but these degrees approximate insensibly; there is a point where these sensations are so greatly weakened, that they are no lon­ger distinct, but become confounded one with the other. This point depends on [Page 110]that disposition of the body, which con­stitutes uniformity, or rather serenity of temper; an indecisive character, and so much the more indecisive, as these sensa­tions are the more confounded.

Finally, as the mechanism of the body, to which these sensations of pleasure or of pain, which are the source of a me­lancholy temper, are to be imputed, is changeable, so the temper varies likewise. Observe however that the agreeable sensa­tion, which depends on the perfect state of the machine, can be easily destroyed; whilst the disagreeable sensation, which results from the primitive constitution of the solids, is in the other extreme. Thus it is not unfrequent that gaiety yields to sadness, but a melancholy temper seldom gives way to mirth.

Hitherto we have discoursed of the temper only; let us examine that vivacity and that languor of the soul, which ever accompany the vigor or languor of the body, one of which wears so strong an appearance of gaiety, and the other of sadness.

We must consider the languor of the soul, less as a weak degree of sadness, al­though [Page 111]it has all the appearance of it, than as a state of indetermination, where­in Man possesses not sufficient power to determine himself. Objects ever remain the same; they likewise act on our senses by the same mechanism: but whilst the body is affected with a languor, their im­pression on our organs^* is much weaken­ed by the deficiency of the organic elasticity of the fibres. Thus weakened, the sen­sations communicate an impression, too feeble^† to excite any strong emotion in the soul.

There is a surprising relation in Man, as in every other animal, between sensa­tion, sentiment and action. External ob­jects act upon the senses, the senses mo­dify their impression, convey it to the soul, and the soul consequently re-acts on the body. Thus in the animal oeconomy, the action of external objects on the senses is ever succeeded by the re-action of the soul on our organs. The one is the cause, the other the effect; this cause and this [Page 112]effect are ever proportionate. The ges­ture of the body, the tone of the voice, the rapidity of the speech, and every mecha­nical motion, by which the soul externally displays its emotions, have necessarily a force proportionate to the vivacity of these emotions.

In voluntary motion the same relation is observed.

Man cannot see his own good without making some efforts to obtain it, nor be exposed to any evil without attempting to avoid it, and that ever with an ardor proportionate to the greatness of the good he seeks, and of the evil he would avoid. Thus when the vigor of the body decays, the sentiments are destitute of vivacity.

The first cause of the languor and vi­vacity of the soul is in the organs, which receive the impression of external objects; the second in the soul, which experiences this impression, and re-acts upon the or­gans. In the former case, these impressi­ons on the body have but little effect on the soul; in the latter, the emotions of the soul have but little effect on the body.

The force of the sensations of the body, and of the emotions of the soul, is ever [Page 113]absolutely necessary to the vivacity of the temper and character; but these causes alone are not sufficient; for the soul and the body are without any immediate com­munication. Thus, however powerful the sensations of the body, and the emo­tions of the soul may be, they are inef­fectual, when not propagated reciprocally from one of these substances to the other. The nervous fluid being the medium of communication between these two sub­stances, it follows, that the impulses, transmitted by either, are very much mo­dified by the action of this fluid; and their force is ever in proportion to the vi­vacity of this action.

Whilst the body is languid, this action is feeble; for the same causes which pro­duce the vivacity of the impressions of objects, continue it whilst it is propagated; and the same causes, which are neces­sary to transmit to the soul the vivacity of the sensations of the body, are so like­wise, to transmit to the body the vivacity of the emotions of the soul.

Hence Macrocephali are more viva­cious than others, and Microcephali less so.

[Page 114]Hence, likewise, extreme fatigue seems to extinguish in our hearts all sentiments and desires. Hence, after a considerable haemorrhage, the emotions of the soul are^* without vivacity, and when our strength is dissipated, we feel only the gentle emo­tions of an indecisive will; hence rage and courage decrease with the blood. When enquiring into the causes of vigour of body, and of the force of sensations, I proved, that three causes contribute thereto^†, the primitive elasticity of the fibres, the large diameter of their cavity, and a sufficient quantity of the nervous fluid. These concur to produce that vi­vacity of our desires and actions, which forms the sprightly character; whilst the lax texture of our fibres, their small di­ameter, and a deficiency of the nervous fluid form the effeminate and indolent.

Such are the causes of that analogy, of that harmony which is ever observed be­tween [Page 115]the temper of the soul and the or­ganization of the body, or, so to express myself, between the state of the body and the state of the soul.

Hitherto we have seen in what manner the body characterises the soul; but the influence of the corporeal on the imma­terial part in Man, ends not

In what Manner the Disposition of the BODY varies the Prospect of NATURE.

The soul is ever in a disposition analo­gous to that of our organs: this I have already proved: it has likewise been shewn^*, that there is a constant analogy between the impression of external objects and the internal disposition; that those objects are pleasing and agreeable, when the soul is affected with joy; much less so when it is affected with grief: conse­quently the mechanism of the body chan­ges the prospect of nature, the reason of which has been already assigned.

Organization renders the Temper constant.

Although the temper be variable, it ne­vertheless is not equally subject to change in every individual. We have seen how the state of the body forms its character; but the heart has other fources of joy and sadness than these.

If the soul experiences agreeable or painful sensations, which arise from the state of the body, it likewise experiences others which are independent of it; these must change its natural state, when they are contrary to those which are transmitted from the general organ of feeling, and with so much the more force, as they have greater vi­vacity. The soul united to a sensible and vigorous body must therefore be of a tem­per the most inconsistent: but more es­pecially if it be not determined by the constitution of the body; for at that time the sensations affecting it preserve all their energy, and as if it had no character, its temper varies with the impressions it receives.

On the contrary, vexations change not the temper of the gay; such feel them [Page 117]only as slight pains, which ceasing, the soul re-admits the sweet impressions of pleasure^*, and instantly re-assumes its wonted gaiety.

On the other hand, pleasure makes very slight impressions on the sad; constantly concentrated within themselves^†, they are sensible only to grief, and never admit any strong impulse of joy.

Thus, by diffusing their colours over objects, our sentiments acquire longer du­ration; joy contributes to perpetuate joy in the heart, and sadness to perpetuate sadness.

The mechanism of the body, therefore, in characterising the temper, contributes likewise to fix it.

Organization renders MAN volatile or thoughtful; talkative or silent.

If we observe the influence of the pas­sions on the body, we shall perceive, that joy shews itself externally by precipitate [Page 118]motions^*; on the contrary, sadness ren­ders the limbs motionless, and appears immoveably^† fixed in the heart. This latter recalls Man's thoughts within him­self, whilst the former continues to act outwardly: thus organization, by fixing the temper of the soul, renders the gay volatile and unsettled; the sad reserved and thoughtful.

Organization renders MAN morose, cruel, communicative or benign.

Sadness incessantly centers the mind within itself. ‘He whose thoughts are wholly on himself, and who separates his interest from that of others, knows neither pity nor generosity.’ Thus that organization*, which renders Man sad, ren­ders him likewise obdurate and cruel; that which renders Man gay, on the contrary,^‡ [Page 119]renders him communicative, benevolent and compassionate. The disposition of the organs likewise produces these effects by another principle; for to the sad, ever centered within themselves by the senti­ment of their own misfortunes, nature ap­pears covered with a gloom, all their ideas are mournful and melancholy: if they speak of happiness, it is to complain of the want of it; they seem never to have enjoyed any of the pleasures of life.

The sight of the happy causes the me­lancholy sufferer to feel the full weight of his miseries; it increases his sufferings, by irritating his sensibility, and wounding his self-love. Thus he is grieved at the sight of those pleasures he cannot enjoy, and is envious of that felicity which flies from him and is possessed by others; he would willingly see all beings groaning around, and tormented with him: as if the num­ber of his sufferings were diminished by those which he inflicts upon others^*, he [Page 120]takes delight in disturbing their pleasures, poisoning their happiness, and becomes cruel and malevolent^*.

How different the joyful Man? The soul ever engrossed by agreeable senti­ments, pleasing images, flattering ideas, is but seldom afflicted; sadness has but little power over a mind so disposed: ever ready to take all things in good part, its afflic­tion must be very severe, if it be obliged to grieve. Thus that disposition of the organs, which produces gaiety, gives at the same time an amiable character to the soul, and likewise generates benevolence.

The Man of a gay disposition, being contented with his lot, is unenvious of others, and so far from desiring to render their lives unhappy, he endeavours to pre­vent their being so; not from pity to them, but from love to himself: his heart over­flowing with joy, reluctantly supports whatever would afflict it, and hastens to remove every painful impression, which either prevents its amusements or inter­rupts its natural gaiety.

Organization renders MAN suspicious and mistrustful.

I cannot quit a subject so extensive: the simple disposition of the machine which characterises the temper, charac­terises the human heart in so many other respects, that it seems to be inexhaustible.

The sad are suspicious and mistrustful; they imagine every person that approaches them ready to deceive: in proportion as their grief is more acute, their suspi­ons are increased, and nature is covered with a darker veil.

Whence does this proceed? We are not, as is commonly done, to account for it, by saying, that mistrust is natural to a deceitful mind, and that no one can be suscipious who is incapable of deceiving. This maxim is true with regard to men absolutely ignorant, but not with regard to those who have been instructed by ex­perience: besides, we have no proof, that the sad are less just than the joyful; on the contrary, if we observe misanthropes, souls gloomy by constitution, we shall [Page 122]find that plain dealing is one of their cha­racteristic qualities; we know with what liberty they indulge themselves in offen­sive expressions, and how little trouble it gives them to speak the most disagreeable truths.

It is not in that so often repeated max­im, but in the state of the body, that we must look for the cause of this phenomenon. External objects ever take their colour­ings from the sentiments which the soul at that time experiences, and it has been demonstrated, that the prospect of nature is in the mind only: now that particular organic disposition which produces a me­lancholy temper, occasions likewise loss of vigor. Weakness and pain generate sadness and timidity, and from these two dispositions of the soul united, naturally result mistrust and suspicion: for the fee­ble, being more obnoxious to danger than the strong, more assiduously seek to avoid it, are more provident and better prepar­ed against snares, obstacles, and every kind of evil. On the other hand, the sad collect in their minds every difficulty, exaggerate subjects of fear, easily despair, [Page 123]and believe every thing to be gloomy a­round them.

Besides, the pensive character of the sad, and the natural succession of their ideas, incessantly exciting in the mind thoughts analogous to the sentiment of sadness then present, creates obstacles, objections, sub­jects of fear and terror.

Organization characterises the AFFEC­TIONS.

There is a constant determinate relation between the organization and the affections of the heart.

In the languor of disease, the prospect of Nature excites no emotion: the amo­rous chant of birds, the cool refreshing breeze, the enamel of flowers, no longer transport the soul; insusceptible of joy, the image of pleasure charms it no more. At that time, therefore, we are feebly de­termined to action^*, and if roused there­to, [Page 124]are unable to continue; we sink under it, and sigh for repose. But when the fibres are sensible, elastic, and abundant­ly supplied with the nervous fluid, the smallest objects make strong impressions on the organs, and forcibly affect the soul. The soul at such time can re-act on the body with equal vivacity, and the repres­sion of its emotions is as ungrateful as action in the preceding.

The soul, when united to a sensible and vi­gorous body, is therefore inactive, and less patiently endures inaction than exercise; but when united to organs composed of lax fibres, it is indolent and effeminate.

The soul, united to gross organs, loves lively amusements and noisy pleasures; to delicate organs, refined pleasures and peace­able amusements.

Brilliant colours are pleasing to robust persons; such are passionately fond of warlike music, penetrating odours and spirituous liquors. Persons of delicate texture and great sensibility, on the con­trary, [Page 125]love light colours, soft music and sweet odours. In the pleasure of the mind the same diversity appears; the deli­cate and the sensible, fly those noisy a­musements in which the robust and vigo­rous so greatly delight; they love refin­ed enjoyments, the sweet effusions of the mind, têtes à têtes, and every plea­sure which arises from the tender union of hearts.

The cause of this phenomenon is, on one hand, the relation observed between the sensibility of our organs and the force of the impression of objects; on the other, the organic disposition which characterises the temper.

With the impressions we receive from objects, constantly concur two analogous sentiments of the soul; love, with a­greeable sensations; and hatred, with painful.

All men seek pleasure and fly from pain; in this they all accord: but we never seek objects but from the relation which they have to ourselves, that is, from [Page 126]the degree of pleasure they can commu­nicate.

The sentiments of love and hatred must therefore change with these rela­tions.

A weak sight, or rather an eye ex­tremely sensible, delights not in glar­ing colours; such being prejudicial to it. A delicate ear, delights not in vio­lent noises for the same reason: what­ever is injurious to the senses, is pleasing to no one. On the other part, every be­ing loves to be sensible of its own exist­ence. Thus, whenever any one avoids too violent sensations, he seeks those on­ly which have a certain degree of vi­vacity.

Hence the soul, which is united to gross organs, being too weakly affected by gen­tle and delicate sensations, loves those which are violent and strong; such as spirituous liquors, glaring colours, the sound of the horn, trumpet, drums, and all kinds of noisy amusements: whilst the soul, which is united to a delicate and sensible consti­tution, [Page 127]delights only in gentle sensations, tender colours, expressive music, in a word, in every kind of refined and deli­cate pleasure.

But in these relations between the affec­tions of the soul and organization, there is a more than simple proportion between the force of the impression of objects and the delicacy of the senses; for many mode­rate pleasures are devoid of tenderness, and a great number of amusements which can­not be classed with the noisy, excite no gentle emotion.

What then determines the soul, which is united to delicate organs, to tenderness? It is the constitution of the body, but con­sidered in another point of view.

I have demonstrated, that the state of the body, which renders the temper gay, likewise renders Man a lover of dissipa­tion; whilst that, which renders it me­lancholy, renders him pensive. But that disposition, in which the functions of the organs are easily performed, and is the medium between vigour and imbecility, [Page 126] [...] [Page 127] [...] [Page 128]affects the soul with an agreeable languor, which pleasingly allures it back within it­self; such is the state of the body after the moderate loss^* of spirits; such is the last stage of convalescence when it just borders on perfect health, and such is the habitual disposition of bodies which are delicate and sensible. The gentle lan­guor we then experience, and which is a disposition to tenderness, conveys to the soul an agreeable sensation with which we desire to be affected, and which we che­rish in the heart. Hence we delight in every thing which tends to preserve it; as, affecting music, amorous discourses, and every pleasure productive of tenderness and love.

But the affections of the soul are deter­mined by the organization in a manner yet more particular.

The prevailing passion, in those affec­tions of the soul which have a physical ob­ject, is ever fixed by that sense which is [Page 127]the best constituted, and by the most sen­sible organ. He whose organs of pleasure possess sensibility superior to that of his other senses, is libertine and lascivious. He whose palate, or rather whose tongue, is the most delicate of his organs, is a drunkard or a glutton. He whose hear­ing is exquisite, is passionately fond of music.

I have said, that the reigning passion is ever determined by that organ which is the most sensible: this is evident, since Man seeks pleasure with an ardour propor­tionate to its vivacity. But if, of these enjoyments which he attains, one part ex­clude another, he ever prefers that which is the most engaging. The more sensible the organs, the greater the pleasure; for we can at all times proportion objects to the senses when too delicate; but we can never proportion the organ to objects when it is deficient in sensibility.

The gay love joy and seek comic or mirthful amusements; the sad, on the contrary, delight only in those which are [Page 128]sad and mournful; they delight to re­late and hear related tragic adventures, shun gay company, fly to deserts, woods, caves, gloomy forests, and savage na­ture.

It is easy to conceive why the gay de­light in joy, this being of itself agreea­ble; but by what caprice do the sad de­light in sadness, in tragic and mournful amusements? If we attentively consider it, we shall find the cause of this surpris­ing phenomenon in the disposition which the soul receives from the body, combin­ed with self-love. I have said, that we seek after those things only which have some relation to ourselves; this is true in more than one respect. The sad by constitution, being incessantly affected by a disagreeable sensation, vexed that he is only conscious of his existence by his sufferings, envious and jealous of what he does not possess, and what if he were pos­sessed of, he could not enjoy, hates those who are less unhappy than himself; and by a natural consequence, shuns all so­ciety [Page 129]where there is the least appearance of gaiety. The idea that himself is not the only miserable being, alleviates his torments; the thought that others partici­pate his sufferings gives him ease; thus he recounts tragic adventures, and is pleased at the sight of another's misfortunes. As the only pleasure he can enjoy is that of afflicting the happy, and as the only mean he possesses of relieving his own misery, is the indulging himself in reflecting on the sufferings of others, he flies to solitude, to savage and desert nature, where he may, without interruption, indulge the gloomy reflections of his soul. Thus the physical sways the moral part in Man, and the constitution of the body generates the af­fections of the mind.

I shall now prove, that the force and duration of these affections depend whol­ly on mechanical causes.

The relations, which are observed be­tween the sensibility of the body and that of the soul, are likewise observed between the state of our organs and the character of our sentiments.

[Page 130]The force, the vivacity, the duration, the violence of the sentiments of the soul, are all of them effects of organization.

The sensations are undoubtedly not the cause of the passions; but sensibility is the measure of their force; for the desire of being happy, which blindly leads us in quest of pleasure, and prompts us to fly from pain, ever carries us thither with an ardour proportioned to the greatness of the good we pursue, or of the evils we avoid.

As the degree of the good and of the evil is ever determined by that of sensibi­lity, the passions must draw their force from the organization; the sensibility of the soul being ever determined by that of the body.

There is a surprising relation in Man between sentiment and action. He cannot perceive his good without making some effort to acquire it, nor be exposed to evil, without attempting to avoid it. This I have already observed, but there is a ne­cessity of repeating it here. If it be evi­dent, as undoubtedly it is, that Man ever [Page 131]yields to sentiment, and that the degree of the good and the evil is determined in every individual by that of sensibility, it is plain, that the more sensible Man is, the greater efforts he will make to enjoy that good, or avoid that evil.

But this relation between sentiment and action is not restrained to voluntary mo­tion; the action of external objects on the soul is ever followed by the re-action of the soul on the body. Unable to restrain the emotions agitating it within, the soul displays them externally by impressions purely mechanical, and ever with a force proportioned to that of its sentiments. Thus in the violent passions, we are ever transported with strong and precipitate motions; but when all is placid and quiet within, all is calm and serene without.

Yet the man, who is ardent in his de­sires, is not ever impetuous in his actions. Vivacity of motion supposes only great organic elasticity of the fibres: impetuo­sity requires not only great organic elas­ticity of the fibres, but force and solidity of the organs likewise.

[Page 132]The duration of a passion is determin­ed by its objects. The sensual are ever momentaneous: those, which have some natural want for their cause, continue not after this want is supplied; the others are not more durable. But those, which are produced by the imagination, are incom­parably more constant; they reign through­out the day, and disappear not at night; they attend us when we retire to rest, and reign in the mind when all the senses are locked in sleep. This duration of the artificial passions, so long when compared to that of the sensual, depends on the or­ganization combined with the nature of their different objects.

It is the property of our pleasures mu­tually to destroy each other, on enjoyment, and to have no continuance without the assistance of novelty. The objects of sen­sual pleasures are extremely confined, compared to those which are imaginary; for the first are determined by nature, whilst imagination, ever active, can in­cessantly modify its objects, and present them under new appearances. Moreover, in [Page 133]the sensual passions, the sentiments which then engage the mind, are felt only by means of external objects; when these objects cease to act, the sentiment imme­diately becomes extinct. Thus in sensual love, the sweet emotions of the soul, and the spirits, are lost together: but in the artificial passions, the heated imagina­tion exaggerates objects, adorns and em­bellishes them; the soul, seized with an enthusiastic ardor, affects the body with strong emotions, and thereby retains its tender sentiments, even when pleasure is extinct.

Nature cannot long support the violence of an extremely active passion; the sentiments forming this passion vanish, and instantly re-appear. The cause of this phenome­non is physical. In every passion, whilst the soul is fixed on its objects, the^* or­gans are tense; this is observed even du­ring sleep, when the commerce of the soul with the body appears to be interrup­ted. In the agitation of a troublesome [Page 134]dream, the pulse becomes quicker, the complexion more lively, the body is va­riously agitated, Man awakes and finds himself in his bed, exhausted by fatigue, and wet with sweat and with his tears. In the passions, tension of the body ever ac­companies tension of the soul. This ten­sion of the sentient substance is not only determined by that of the organs of the body, but wholly depends on it; for when the body is affected with languor, the soul receives no strong sensation, it is insusceptible of it^*.

Let us then conclude, that if the soul cannot long sustain very strong emotions, it is because the fibres of the body cannot endure great tension for any length of time.

The violent passions consist in a se­ries of sentiments, which are interrupted, one instant, and renewed the next; the succession of these sentiments is perceived only at intervals.

[Page 135]The duration of each particular senti­ment, and that of their total successions, depend on the organization. For if the soul always requires the mediation of the body, to receive any strong sensation; if it be unable to fix itself without the con­currence of the other; it plainly appears, that the duration of every strong emotion of the mind, and that of all these emo­tions which are successively experienced, depends on that faculty of the body, whereby it continues tense a longer or shorter time; a faculty dependent on the different degrees of organic elasticity and solidity of the fibres.

Thus the soul, which is united to strong and elastic organs, is subject to violent and durable passions; that which is united to delicate organs, unable to endure long continued tension, passes incessantly from one impression to another; and never ex­periences any which is lasting.

In the violent passions, the soul is truly passionate, only when engaged with its objects; when it ceases to be affected thereby, the passion expires; yet the same [Page 136]internal disposition continues, even when the soul is engaged with a new sentiment. The cause of this phenomenon has been already shewn to be in that impression^*, which sensibility produces on the body, and which in its turn, from an effect be­comes a cause, preserving in the soul the sentiment which produced it, and recalling it there, if at any time its object dis­appear.

But this impression which the passions produce on our organs is not equally dura­ble in every individual. The more strong these emotions are, so much the more ap­parent is this effect; for the more strong is the impulse communicated to the ner­vous fluid by the soul, and the more ex­treme the tension of the fibres, so much the more is their elasticity weakened, the equilibrium between these two powers of the circulation destroyed, and the circu­lation itself obstructed. At this time the nervous fluid produces, especially in the plexus nervosi, a very great constriction, [Page 137]proper to continue the emotions of the soul.

The duration of this impression is at first, therfore, in a direct ratio of the de­gree of sensibility, afterwards in an inverse; for the more elastic the fibres are, so much the more they yield to the action of the nervous fluid, the more forcible like­wise is their re-action, and the equilibrium much sooner re-established. In estimating these relations, we find the duration of this impression to gain less by an excess of sensibility in the organs, than it is preju­diced by an excess of organic elasticity.

In a body delicate and vigorous, the soul must therefore be subject to passions the most violent and the least durable; in a body indelicate and robust, to those which are the most constant.

Hence the reason why men of great sen­sibility are easily provoked to anger, whilst the indelicate and robust are with diffi­culty inflamed. Hence the reason why the anger of the former is like a fire of stubble, which blazes and is soon extin­guished; while that of the others is of [Page 138]long continuance: once excited to fury, their souls cannot be appeased, resentment remains after revenge is gone, like the agitated ocean, which subsides not to a calm till a considerable space after the storm. But the duration of the passions is produced by many other causes. Whilst Man is intent upon the object of his pas­sion, as he is ever surrounded with beings adapted to distract him, he easily loses sight of it: this very frequently happens. During these moments of distraction, if the sensation which occasioned it be not very interesting, the passion must be re­garded as a latent fire, which instantly blazes forth on the least admission of air.

If the soul be strongly affected by these new objects, the passion revives not, but yields to some other sentiment. Thus the more sensible a man is, the more he is exposed to the impression of external ob­jects, and the more easily will his passions be extinguished.

This is the cause why the virtue of the sprightly is neither regular nor constant; [Page 139]it appears only at intervals, by starts, as if it had no source in the persons them­selves; they being obliged to be frequently recalled to the practice of it: while the virtue of the sedate and robust has the ap­pearance of constant habit.

On the other hand, while the passion is extremely violent, and any sentiment ty­rannizes in the soul, other objects have not power to disengage the attention.

The passions therefore, if they are, on one side, less constant in proportion as Man is more sensible; they are, on the other, more constant in proportion as he possesses greater sensibility.

This is observed more especially in the passions which have a sentiment of love for their basis: when the soul believes that its own happiness depends on the possession of some object, nothing can disengage it from thence; the powerful attractives of pleasure keep it intent on the be­loved object, and admits of no inter­ruption.

From these observations let us conclude, that,

[Page 140]A Man of extreme sensibility, who has only slight affections, must be the most fickle of human kind; he is never so con­stant, as when violently excited by some passion.

The force of the passions therefore depends on the sensibility of the fibres; their violence on their extreme sensibility, and their impe­tuousity on their sensibility combined with their force: the duration of the passions depends equally on the sensibility and elasticity of the fibres, and on their force and solidity. It is thus the physical part in Man gives cha­racter to our sentiments and passions.

How Organization renders MAN open-hearted, or a Dissembler.

To the preceding truths, I add another which arises immediately from them.

The same organic elasticity, which causes the extreme force of the passions, renders Man frank and open-hearted; for the soul cannot conceal its emotions, they rush out precipitately, and appear in his gesture, speech and voice; finally, the repressing of these emotions is ever painful, [Page 141]and even impossible, when the soul is strongly affected. Reserve is peculiar to souls united to organs of lax or very gross fibres; frankness, to souls united to or­gans of extreme organic elasticity.

Men of great sensibility and liveliness, always speak the language which springs from the heart, the language of truth; thus it is by warming the heart of him who is naturally cold, that is, by aug­menting his sensibility, by increasing the elasticity of his fibres, that wine banishes reserve and lays open the heart.

Thus no credit is to be given to persons of known dissimulation and habitual re­serve, unless in the paroxysms of passion. Then only are their words without dis­guise; in these moments, the violence of the emotions of the soul augments the tension of the fibres, affects them with a slight rigidity, frees them from the em­pire of the will^*, makes them drop the mask and appear without disguise.

When you press the chaste mistress of your heart to lay open her mind to you, [Page 142]although she submits with regret to the lessons of her mother, and to the severe laws of modesty, she nevertheless divulges not her true sentiments; she allows she has a friendship for you, and nothing more. But when wearied out with a long and painful resistance, the dissembling fair permits her lover to triumph; while love fires her veins; while she embraces her beloved with transports; clasps him in her arms; presses him to her eager bosom, and her humid lips attract and distil pleasure; her voice is broken and faultering, scarce­ly can she articulate a few words—ex­pressions of tenderness and love.

Observations on the Manner in which Orga­ganization renders MAN obdurate and cruel, compassionate and humane.

Let us again examine the effects of the primitive and organic elasticity of the fi­bres; for what a diversity in the moral character is produced by the different de­grees of these corporeal faculties! What surprising phenomena, of which they are the cause! Principles the most fertile! [Page 143]Principles! whose extent, when fully known, demonstrate them to be almost inexhaustible.

We do not compassionate the miserable, but from an idea of his sufferings; we have no idea of pain till we have experienced it ourselves: if, therefore, to bemoan others, we must have suffered ourselves, sensibili­ty is a disposition absolutely necessary to pity.

If united to gross organs, or to fibres too solid or too lax, the soul becomes obdu­rate and inflexible; when united to or­gans delicate, elastic and vigorous, it be­comes compassionate and tender. Hence pity, although an artificial sentiment, is nevertheless, in every individual, modified by the organization.

The greater the sensibility of Man, he may thence be the more humane; and by a very singular consequence, he may thence be the more cruel. For if, to bemaon others, we must be sensible ourselves, it is equally true, that we discover only that sen­sibility for others which we want not our­selves. The more sensible any one is, the more assiduous is he to avoid pain, the [Page 144]more eager after pleasure, the more en­grossed by himself, and the less concerned for others. If, in these cases, sensibility be fixed on the sensual or artificial passions, which have neither generosity, clemency, nor goodness, for their object; the voice of pleasure drowns that of pity; the heart is contracted and shrunk within itself, the soul, full of the object of its desires, denies its attention to every thing besides, and is no long either clement or humane. If the well-being of others be inconsistent with our own, these affections become more extreme; for if it be a consequence of the love of ourselves, to love those things which are beneficial, so likewise it must be, to hate those which are prejudicial to us. Thus they, whom we now look upon with indifference, become the object of our most extreme hatred, when we regard them as enemies; in the heat of passion we treat them with the greatest virulence, relentlessly seek their ruin, aggravate their misery, and view their sufferings with an eye of satisfaction.

The more sensible likewise Man is, the more fearful he is of pain, and the [Page 145]more timid; the fear of his enemy prompts him to complete his destruction, when­ever opportunity offers. Let us therefore conclude, that the more sensible a Man is, the more he is obnoxious to hatred, his cruelty is greater, and the more atrocious his character.

Another reason, which modifies pity in our hearts, is drawn from that disposition of the body which characterises the tem­per of the mind.

I have shewn that the melancholy hu­mour, by centering Man's thoughts in himself, renders him unsociable, obdurate and cruel.

That, which constitutes good humour, is much more favourable to pity; yet in some particular instances less so. In the gay, the sentiment of pleasure, ever pre­dominant in the soul, nourishes therein ideas of joy, and the sight of the unhap­py generates those of sadness. These therefore are weakened by the former, and consequently make not their full im­pression.

The disposition of the body, which constitutes serenity of temper, is much [Page 146]more favourable; as it leaves Man the en­tire liberty of his mental faculties, and changes not the impression of objects.

But of all dispositions of the body, that is the most favourable which constitutes the tender character, that disposition of the soul which determines it to compassion.

The Man who is constitutionally sad may be just and sincere; the gay may be equitable and meek; and a Man of a se­rene temper may possess the virtues of both. But it is only to the Man of a delicate constitution of body, that Nature has given a compassionate heart; on him only has she bestowed that noble propensity to clemency, that generosity of soul, which takes pleasure in mingling tears with the afflicted, in melting at another's woe, and relieving the oppressed.

Let us add, that it is the same disposi­tion of body which generates in our hearts, that goodness which prevents the requests of others, and that easy communicability of heart, which, in a moment, contracts the most durable friendships, produces that sensibility and tendency of mind, [Page 147]whose first emotions determine our lot, and decide the destiny of our lives.

Organization characterises the Manners.

I constantly return to the sensibility of our organs; so fertile is this principle, so many and so marvellous are its pheno­mena!

The love of happiness is the great and only principle of all our actions, but sen­sibility is the source, or rather the stan­dard, of our vices and of our virtues.

Men of the greatest sensibility may be the most cruel, the most vicious; but to them likewise has Nature given souls of the greatest virtue, of the noblest senti­ments, grandeur and magnanimity.

Men of a little sensibility are beings without virtue, lifeless carcasses wherein you can discover neither fire nor activity.

Farther Observations on the Manner in which Organization renders MAN frank and hasty, or timid and deceitful.

The sensations, which the soul receives from the general organ of feeling, are not confined to agreeable and painful impres­sions, the soul likewise perceives the vi­gour or languor of the body; and this sense of vigour and languor greatly di­versifies the moral character of Man.

The sense of vigour^*, combined with sensibility, renders Man ardent in his de­sires, precipitate in his designs, and im­petuous in his actions; whilst that of lan­guor renders him weak in his desires, slow in his resolutions, and indolent in his conduct.

[Page 149]Those who are vigorous and of great sensibility are therefore furious, vindic­tive, audacious and inconsiderate.

Those who are weak and of little sensi­bility are timid, crafty, indolent and pa­tient.

Organization determines the Force of the SOUL.

It has been already observed, that a de­licate body contains not a mind endued with force.

In treating of the force of the soul, I have destroyed the sophistry which has been used in the application of this term. I have proved, that, properly speaking, there are no minds endowed with force, since every Man is irresistibly subject to sensibility, and held in subjection by the passions. I have shewn, likewise, that in every individual, the force of the pas­sions is ever in proportion to sensibility, and that the sensibility of the soul is ever determined by that of the body. Fi­nally, I have demonstrated, that the force of the soul, if we chuse to make use of [Page 150]that expression, is in an inverse ratio of the sentient faculty.

The soul therefore is more in subjection in a body of delicate and great sensibility, than in a body which is indelicate and robust.

Organization determines the Capacity of the MIND.

There are some men, whose active souls receive few sensations without comparing them; these are the most ingenious.

There are others who compare only a certain kind of sensations; these are less ingenious than the former, and so much the less so, as their souls have a less pro­pensity to compare their sensations, and to form ideas therefrom. The souls of others again are so little active, and so greatly averse to thinking, that they neither com­pare [Page 154]nor combine any thing at first sight; they require sensations which are both strong, and many times repeated, before they are brought to compare them, and to form any idea: such, being more or less stupid, differ not from the weak minds, but in the small number of their ideas, which they so laboriously produce.

No man desires to know, but because he desires to be happy: he who is without desires, and without fears, will certainly not give himself the trouble of comparing his sensations, of combining his ideas, and reasoning therefrom.

Passion therefore is the cause of this activity of soul, this perpetual fermenta­tion of reason^*; without it, the mind, unaffected, unsupported, falls into a lan­guor, and is immersed in sloth.

[Page 155]The mind therefore thinks only when it has an interest in thinking: this interest may be of many kinds; one finds it in the pleasure which he receives from the knowledge of things; another in the plea­sure he takes in displaying his learning, and attracting regard; a third in the means of procuring the conveniences of life by his knowledge. But whatever the object may be, the passions ever ac­tuate the mind; by their activity its fa­culties unfold and rise to perfection. To arrive at excellence of any kind, Man must be animated by some passion; and the more violent his eagerness to succeed, the more efficacious are his efforts for that purpose. For only the violent passions produce illustrious, heroic and great men: he who is animated by no passion, does nothing to render himself illustrious, and is wholly insignificant. Men therefore are more or less ingenious, as they possess greater or less sensibility.

The human understanding is undoubt­edly greatly indebted to the passions; but if the passions are necessary to render the mind active, they are not sufficient to pro­duce [Page 156]a creative imagination, or a great genius: they can indeed render Man eager after success; but they supply not the qualities, which are necessary to the ac­quisition of it. Some physical dispositions therefore are required, together with the sensibility of our organs.

Let us inquire into the nature of these dispositions.

At our birth none of the mental facul­ties is unfolded, none in exercise^*, not even instinct. But whether the soul ex­isted before its union with the body, or whether it had any peculiar method of acquiring knowledge or not, it is most certain, that when once it has become subject to the laws of this union, it no longer retains aught of its former state, not even the remembrance of it.

Every man possesses the power of judg­ing; but even although we suppose that every man possessed it alike, the minds of individuals would not be less different; for the understanding can never proceed [Page 157]alone; but requires the concurrence of the sensitive faculty, or rather that of the sensations.

Examine the productions of the human mind, the most singular works of imagi­nation, even those which have the least analogy to nature; all have for their sub­ject, sensible objects, or relations of these objects. Almost all our thoughts are cor­poreal images, and of the most abstract ideas there is none which is not fixed by the senses; there is not throughout all nature a work of the pure intellect. If we desired, for instance, to form any idea of the Deity, or his attributes, we should consider him under human relations; at one time, as a beneficent father: at ano­ther, as a glorious King; now, as a be­nevolent master; then, as an offended Judge.

He who would rise to the first of Be­ings, and contemplate him in his essence without the aid of corporeal images, per­ceiving no relation between God and him­self, knows not how to form any notion of him, and is lost in the sublimity of the idea. Thus all religions are supported by [Page 158]a gross worship, which interposes mate­rial objects between the supreme Being and Man. One contemplates the Deity in his works, another worships him under an imaginary resemblance; for the heart, as well as the mind, is ever fixed by the intervention of the senses.

Thus likewise, when we form to our­selves a notion of the soul, we ever repre­sent it as a thin shade, or subtil matter; in short, as a corporeal being, if we form any image of it at all.

Whatsoever object we chuse, the case is the same; for let us employ our utmost efforts to form ideas wholly intellectual, or to conceive pure spirituality, the only consequence of the attempt is to involve the mind in greater darkness and confu­sion.

Every idea therefore is formed from the true or false relations of sensible objects; whence the understanding never operates without the concurrence of the sensations: in proportion as they are removed from their objects, the ideas we would convey become unintelligible; without their assistance our ideas either escape us, or they are ne­ver formed at all.

[Page 159]Let us conclude from the preceding, that the sensations are the basis of all our knowledge.

What a variety of minds therefore must be produced by the different structure of the organs of the senses, the only means whereby we can have communication with the various beings which surround us.

Our knowledge is neither increased nor perfected but by the comparing our sensations. The greater the number of sensations to be compared, so much the more numerous are our ideas; the more distinct these sensations, so much the more clear are our conceptions, and the more exact these comparisons, the more perfect our knowledge must be. On the contrary, the smaller the number of our sensations, the more confined is the sphere of mental activity, and the less numerous our ideas; not only from the privation of those ideas which are founded on the sensa­tions of the sense we are without: but from the privation of many others; for it is evident that, as all the parts of ha­ture are connected, the sensations of one sense often serve to discover the relations of the sensations of another sense.

[Page 160]The number of our ideas must there­fore be relative to the number and struc­ture of these organs: whence Man must be less intelligent, less ingenious, in proportion as he possesses a smaller number of senses, and as his senses are less exquisite.

Although there is an intimate relation between the number of sensations and that of ideas, this relation is not equal with regard to every sense; one sense may be confined whilst another is less so.

From a calculation of the number of the objects of the senses, the organ of smelling appears to be the most confined, and that of seeing the least so. The eye is of all the bodily organs the most com­prehensive, and takes in the greatest num­ber of objects; forms, dimensions, co­lours, are all within its district; the va­rieties it perceives in each of these modi­fications of matter infinitely surpass all those within the cognizance of the taste, smelling, hearing, and feeling; that is, of sounds^*, savours, odours, and sensa­tions [Page 161]from the touch. This is evident during sleep; for the many sensations which are retraced in the mind during rest, are so many images of visible objects. The sight therefore contributes more to know­ledge than any of our other senses.

With regard to the nature of our sensa­tions, it is very evident, that, from the different structure of the senses in different individuals, there must be a great diversi­ty in their respective impressions.

Every object must naturally produce on Man, an agreeable or painful impression; for every Man is a sensible being, and eve­ry sensible being must be susceptible of either pleasure or pain; but it does not therefore follow, that the same object should produce, in every individual, the same sensation; their respective senses not [Page 162]being of similar organization. In what­ever manner material objects affect the senses, it is certain, that the same objects affect them not equally in every individu­al, and consequently produce not in the soul the same impressions. The lilly is not beautiful to every eye, neither is the anana pleasant to every palate, nor the song of the nightingale to every ear. I shall not speak here of these diversities in the sensations of individuals, as their cause is utterly unknown; but shall attend to those which are more evident and better understood.

The chief differences between the sen­sations of different individuals consist in their delicacy, in the greatness of their image, and in the number of the objects composing the picture; the two last spe­cies of these differences are peculiar to the organ of sight, the other is common to all the senses.

The more delicate an organ is, the bet­ter it perceives those minute objects which escape organs which are less so. The de­licacy of the senses is often necessary to the acquisition of many sorts of know­ledge; [Page 163]we are indebted for the discovery of the Satellites of Jupiter, and other ce­lestial bodies, of the animalcula in liquors, and of the minutiae of anatomy, to those instruments which have been contrived to supply the imperfection of our senses. These supplements have advanced our knowledge in many respects beyond the point to which it had arrived a few ages ago, and have, in our times, conduced to the discovery of many great and impor­tant truths. But as a delicate organ is more susceptible of irritation, and less distinctly receives strong sensations than another that is less so, it loses on one side what it gains on another, and sometimes more. To what use would the faculty of seeing in the dark serve, if the light of day be painful to the sight; it is very evi­dent, that a person so circumstanced would lose by the exchange. With an eye, like­wise, which comprehends only a small prospect, we can discover particular beau­ties more distinctly, than with an eye which takes in an extensive circuit; but we see not so well the harmony of the [Page 164]whole^*. A too comprehensive organ sees detached parts imperfectly: an organ not sufficiently so discerns not their relations.

By entering into an examination of the sensations which are employed in the se­veral sciences, we might determine what particular structure of the senses is best a­dapted for each; but, in general, organs moderately delicate, adapted to compre­hend a moderate number of objects, and pos­sessed of every faculty (if I may be al­lowed the expression) in a mean propor­tional degree, are the most advantage­ously constructed. In cases where pene­tration depends on the number and dis­tinctness of the sensations, and on the comparing the sensations together, he whose senses are best constructed, must therefore have the greatest natural quali­fications.

‘But we perceive not, says a celebra­ted philosopher^†, that persons whose senses are dull, sight imperfect, hear­ing [Page 165]thick, and smelling greatly if not wholly decayed, have slower capacities than others.’

The observation is just, if understood of civilized nations; for how is it possible to perceive the advantage of a superior orga­nization of the senses in society, where Man can easily find means to supply the imper­fection of his senses? What defect is there of the organs, for which art affords not some remedy? The short-sighted are fur­nished with telescopes which bring near the most distant objects; the weak-sighted are supplied with microscopes, angiscopes, and other glasses, which make them distin­guish minute objects which would other­wise escape them. To persons of dull hearing, are given acoustic instruments; for those in whom the sense of smelling is decayed, or taste imperfect, are prepared concentrated odours, savours, juices and quintessences. Supplied with these sub­stitutes, is it strange that men, whose senses are imperfect, should become, in this respect, equal to those who have re­ceived from nature the most perfect organs? Take your observations from persons des­stitute [Page 166]of these resources of art, and then determine.

‘Nevertheless, he replies, Man is not the more ingenious for having exercised his ears and eyes.’

I shall prove hereafter (in opposition to the vulgar opinion) that our senses are not rendered more perfect by use: but sup­posing it to be true, what would our phi­losopher infer from his vague assertion against the advantage of well organized senses? Without doubt Man may have exercised his eyes and ears, yet not be more ingenious than another who has not; he may even possibly be less so: for the mere exercise of our senses can never in­crease our knowledge; they must have been also exercised on subjects which are not only important, but relative to some science.

Were a man to spend his whole life in examining grains of sand, he would not be less ignorant, although he might know their different configuration, than when he first began; but if, instead of this unpro­fitable and barren occupation, he had pas­sed the same length of time in examining [Page 167]plants, animalcula, and in forming such observations upon natural history, as have rendered Malpighi, Lewenhoeck and Mus­chenbroek so famous; do you suppose he would have profited nothing by this exer­cise? Do you imagine, that his knowledge would neither have been increased, nor his understanding improved? The least reflection would have discovered the futi­lity of these objections. However, it was necessary to employ some time in the re­futation of them; as the celebrity of the objector may be of great weight to the generality of readers. Let us conclude, that the better constituted the senses are, the more ingenious Man is, caeteris paribus.

Organization characterises the MIND.

Men not only differ one from another in the number of their ideas, but likewise in the nature of their knowledge. The difference of minds therefore depends not wholly on the multitude of its judgments, but on the manner in which they are formed.

[Page 168]Does a man judge without much reflec­tion, does he form his ideas upon relations which are apparent only? He is then su­perficial. Does he form his ideas upon true relations? He is a Man of sound under­standing. Does he mis-improve these re­lations? He is in this case of an erroneous understanding. Does he forge chimerical relations, which have neither reality nor probability? He is a fool. Does he too negligently compare his sensations? He is weak. Does he exercise his judgment on­ly upon refined ideas? He is a wit ^*. Does he exercise it on ideas difficult to be ac­quired? He is profound.

He, who has received from Nature the most exquisite, has no advantage over him who has received an inferior organization, unless he cultivate his mind. But if ani­mated with the same passion, they both [Page 169]apply themselves to study, their efforts will be attended with very different success. Whilst the former, without difficulty, sur­mounts the greatest obstacles, advances with a rapid flight in his progress towards truth, and easily penetrates the secrets of Nature; the attempts of the latter will be vain, he meets obstructions every mo­ment, and proceeds with tardy steps in the vast career of science.

I have already assigned some physical causes of the difference of minds; but many others far more important remain yet to be discovered.

Organization assistant or an Hindrance to the unfolding of the MENTAL FACUL­TIES.

It is unknown whether the soul, when disunited from the body, can perceive, think, or remember its sensations and ideas or not; but it is certain, that, when once it is united to the body, the unfolding of its faculties depends entirely on the state of the body with which it is yoked. Let us endeavour to discover the latent reasons of this important truth.

[Page 170]Without sensations there can be no ideas, as has been already demonstrated; but if all our ideas are founded on the sensations, they likewise depend on the understanding by which they are formed. The mind cannot form them in the same manner in every individual, nor can it form them always in the same manner in the same person.

When the impressions of objects are made on the organ, and the sensations are received by the soul, all the functions of the senses are discharged, but not all the functions of the body.

To judge of the relations of objects, we must distinguish these objects with care, examine and compare them under their different appearances: this requires attention.

Attention is the parent of all know­ledge: attention, by applying the mind to the consideration of beings, discovers to us their different properties: attention, by fixing it upon the different phenomena of Nature, investigates its unknown laws and its secret relations, which otherwise escape us: attention produces, from the [Page 171]various combinations of our observations, those sublime discoveries, those admirable inventions, those prodigies of science, those productions of genius, which have been in so many various ways beneficial to man­kind. Without attention every pheno­menon in nature is lost to us; in vain is the soul endued with such noble faculties, in vain does the universe offer its vast and wonderful volume to our sight.

Attention is strengthened by being con­centrated; it then suspends all the other faculties of the mind, and seems to have intire possession of the soul. On the con­trary, it is weakened by being divid­ed: when it has got half way in a geo­metrical demonstration, if any singular object affect our organs, the mind is in­stantly distracted, suffers itself to be en­grossed by this object, and after it has wan­dered a while, endeavours in vain to re­sume the thread of its former thoughts. Thus every sensation foreign to the object present in the mind, diverts and destroys the attention.

To examine objects, to reflect, to me­ditate, the mind must be perfectly calm; [Page 172]no sensation, no foreign sentiment, must then affect the soul. The first thing therefore necessary to the free exercise of thought, and to the unfolding of the intellectual faculties, is that the soul be united to a body, whose vital functions ^* are performed with ease, modera­tion, and regularity; that is, that the powers which cause circulation have a de­gree of organic elasticity, proportionate to the volume and consistence of the fluids.

But it is not enough that the soul be united to a body in perfect health, and ex­empt from disease; for, that the body may not distract the soul from the objects on which it is intent, the sensation which results from the action of our organs must be imperceptible. Thus the disposition most favourable to the reflection, is that state of the machine which constitutes serenity of temper: that, which causes gaiety, allures the mind towards outward objects^†; that, which causes sadness, attracts it within: the one prevents it from examining ob­jects, [Page 173]the other from combining their impressions; both distract it, and interrupt the series of its thoughts. Besides, with that disposition which constitutes sereni­ty, we can contemplate Nature with the greatest advantage, and discern what she really is.

It is only in retirement, and when the passions are at rest, that the soul can re­sign itself to profound meditation: it is only in those tranquil moments, when the soul retires within itself and is wrapt in silence, that we can meditate to ad­vantage.

They who have great sensibility, enjoy least of this liberty of mind; being con­tinually exposed to be acted on by objects, and being strongly affected by their slight­est impressions, they are almost always engaged by externals. This extreme sen­sibility, I allow, may be in some measure remedied by shunning every kind of noise, avoiding the light of day, and retiring to silence and solitude of the country, or by taking advantage of the stillness of the night. But these precautions are practica­ble in certain cases only; yet, though eve­ry [Page 174]precaution should be used, the sensible will still be more obnoxious to distraction: for the delicate and sensible are subject to more wants, more indispositions, and con­sequently to more frequent distractions, than those who are robust and of strong constitutions. Thus almost incessantly influenced by their various wants, and as constantly engaged in the gratification of them, as if unavoidably attached to pre­sent objects, they easily lose the remem­brance of the past, together with the power of considering and meditating on those objects which present themselves to the mind, or rather they never possess it. For during the perpetual flux of tumul­tous sensations which incessantly attract the attention outwardly, they can neither ex­amine nor meditate upon any subject what­ever.

It is therefore extremely difficult, if not impossible, for a soul united to very deli­cate organs, to employ itself in profound meditation, and to enjoy that liberty which is so necessary to the study of Nature.

Reflection is a state of the mind which requires a sufficient degree of sensibility to be strongly affected, but not enough to [Page 175]make it be irresistibly attracted by pre­sent objects. Only the Man whose soul is united to organs of moderate sensibility, can meditate at liberty and study with success.

Organization renders the Understanding ei­ther just, extensive, delicate, profound; or superficial, confined, erroneous and gross.

Our intellectual faculties are neither developed nor improved, but in propor­tion as the mind compares its sensations. The more it compares them, the more it discovers their relations, and the more numerous are our ideas; the more care­fully it examines them, so much the more perfect is our knowledge.

I have distinguished two powers of the understanding, that of perceiving and con­sidering objects, and that of pronouncing on their relations. The first is the basis of the second, and necessarily precedes it. What then is requisite to enable the mind to form a sound judgment of things? An accurate perception of them. It is therefore on the greater or less degree of attention we employ in examining [Page 176]objects, or rather on the different apti­tude of the mind for attention, combined with the time it is able to support it, that the justness of our judgments and the character of our ideas depend.

To acquire profound ideas, we must for a long time, and without distraction, contemplate the same objects, consider their relations, their difference, examine, compare and combine them in many dif­ferent shapes, that we may afterwards consider them under unobserved appear­ances, and discover their hidden relations.

I will not however say, that every great discovery has been made by gradual series of combinations and complicated observa­tions. Sometimes the mind overlooks the intermediate space, and perceives its ob­ject at a distance amidst surrounding darkness: but if in this manner it arrive at truth, it must nevertheless return to observation, to experience, and to this gradual series of combinations, to verify these new ideas, and connect them to o­thers which have been already acquired. Thus having at once traversed an immense space, it is afterwards obliged to pass over [Page 177]every intermediate degree which separates the two extremes, returning circularly to the point from whence it at first set out. Such is the progress of the human mind in discoveries of every sort.

Thus a person desirous to acquire new knowledge, or verify that which he has already acquired, can never accomplish his design, but by a long and close exami­nation of the phenomena of nature.

It is therefore only to attention more or less strong, more or less continued^*, that we owe the superficiality or profundity of ideas.

[Page 178]This different aptitude of the mind for attention, and the space of time it is able to support it, absolutely depend on organiza­tion: for the mind becomes fatigued just as the body does, and both at the same time.

It is unknown whether the soul is re­ally fatigued; for our knowledge of things is not sufficient to demonstrate whether an immaterial substance is, or is not, naturally susceptible of lassitude; but without the least doubt, the soul, when once it is unit­ed to the body, and during the whole con­tinuance of its union therewith, experi­ences a sense of fatigue as frequently as the body.

Might I have leave to offer my opinion upon so delicate a subject as this is, I would declare for the negative, and would support it thus.

Since the sense of lassitude is common to both soul and body when united, it is evident, that the soul must become fa­tigued together with the body.

The lassitude of the mind is partly the lassitude of the body itself^*, which is [Page 179]communicated to it by the general organ of feeling, and probably it is no more than this; for since the mind, to be in­tent, requires the fibres to be tense, and as the fibres are ever fatigued by their ten­sion, it is not to be wondered at that the soul should cease to be intent, when the fibres cease to be tense, or, which is the same, the mind ever appears fatigued when the body is tired, and the body is tired at all times when the mind is fatigued. Be­sides, we have no idea of the lassitude of the soul, but by the weakness of its thoughts and emotions, and by their short continu­ance on the same subject. When the bo­dy is tired, that is, when the organs are affected with languor, the functions of the soul must needs be languid, the ideas scarcely distinct, and the vivacity of the sentiments decayed^*. This has been al­ready explained.

[Page 180]It is therefore evident to me, that the lassitude of the soul is only lassitude of the body^*, and that in this phenomenon, as in many others, the reality is concealed by the appearance.

But whether it be so or not, this is cer­tain, that the mind is fatigued together with the body. This is an observation which universally prevails, yet no one has hitherto thought proper to deduce the na­tural consequences from it.

When the body is fatigued, admitting that the soul really fatigues the body by application, let us be ever so desirous to continue our meditation, and make what­ever [Page 181]efforts we please, we cannot long keep the mind fixed on the same object, nor fix it there for any time strongly. The soul therefore cannot continue its attention, when the fibres have lost their tension.

It is therefore erroneous to suppose, as many philosophers have done, that our aptitude for attention solely depends on the power of the passions. It is true, that the greater interest we take in applying ourselves to any particular study, the longer we can support attention; passion can then employ the whole strength of the body, but nothing more: hence let the passion be ever so violent, attention is always proportionate to the elasticity and force of the fibres.

Besides, forced attention is more preju­dicial than favourable to our study. In the first place, it cannot be very strong, from the painful sensation which ever ac­companies it: its duration likewise is very short; for when the organs are once wea­ried, they act but with little force; be­sides, the body is exhausted by those vio­lent efforts, and Man loses by its disordered state all the time which he endeavours to [Page 182]gain by this prolongation of attention, and sometimes even more.

Such are the physical causes of many diversities of mind; causes which have hitherto been unnoticed by philosophers, although they so naturally arise on exami­ning the phenomena I have now under­taken to explain. And here let us repeat our first principle, in order to a combina­tion of its effects, and that we may de­duce its proper consequences.

Attention is ever proportionate to the or­ganic elasticity and force of the fibres. To pro­duce profoundideas, the mind therefore must be united to organs composed of fibres which are both strong and elastic; the mind, if united to in-elastic and weak organs, is trifling and supercifial in its operations. Thus a Man, whose constitution is deli­cate and sensible, is not capable of pro­found disquisitions: too weak to sustain long meditation, and too sensible to lead a contemplative life, he beholds Na­ture without attending to particular parts, incessantly flies from object to object, glances upon them, and dips not beneath the surface.

[Page 183]However, I do not pretend to say, that every man of strong and vigorous consti­tution is thus profound; for, besides this physical disposition, his talents must be cultivated; all I would be understood to say is, that only a man of such a consti­tution of bodily organs can arrive at this state; others may, indeed, have a great number of just and solid ideas, but never those which are profound and well con­nected. That sublime knowledge, which is derived from the constant study of Na­ture, is what they are unable to acquire of themselves; on the contrary, they must be initiated in it by others: their minds may be congenial with the minds of Pope and Voltaire, but will never rise to the dignity of Newton's or de Montesquieu's; they may be called men of wit and learning, but never men of depth.

To be just, our ideas must be distinct; but these qualities are not always united. To conceive distinctly, it is sufficient that our sensations be well expressed, and that the mind be exact in pronouncing on their apparent relations; but to conceive justly, there is required a perfect knowledge of [Page 184]every relation necessary to form a solid judgment. Thus ideas may be distinct, yet not be just.

We may therefore from this cause, rea­son justly upon one article and falsely upon another; but in every case, where to dis­cover the true relations of beings, it is re­quisite that we attentively examine them; in every case where the knowledge of things is the result of a great number of complicated combinations; in every case where truth is difficultly obtained, and where there is a necessity of seeing much, if we desire to see well, the justness of our judgments depends on the capacity of the mind, and on its profoundness, or rather, justness and profoundness require the same degree of attention of the soul, and the same organic disposition of the body. With feeble and delicate organs, therefore, Man is incapable of this justness of judg­ment: too weak to consider objects under their various appearances successively, and too feeble to pursue the connexion of things, and to collect a multiplicity of ideas in the same point; he suffers many things to escape, from an inability to retain them, [Page 185]and examines hastily those which remain: thus passing slightly over many objects, and judging of the whole by his imper­fect knowledge of a part, he forms de­ductions necessarily false and inconclusive.

Ideas are particular or general relatively to their object. The same disposition of organs which is necessary to the acquisi­tion of profound ideas, is likewise ne­cessary to the acquisition of those which are universal: for the universality of ideas results from the multitude of relations, which the understanding perceives, unites and collects into one and the same point of view. The faculty of comprehending the system of Nature is therefore given only to those, whose fibres are endued with force and great organic elasticity.

Another effect of this organization of the body, which we could never have sus­pected and scarcely believe, although it is demonstrated, is, that it is absolutely ne­cessary to delicacy of sensations and ideas.

It is an opinion universally received by philosophers, that the senses are perfected by use, and that they are improved by seeing, feeling, tasting, &c. just as the mind is improved by reasoning.

[Page 186] ‘A painter, says one, sees, at first sight, the defects of a drawing, and the dif­ferent tints in a picture, although invisi­ble to other eyes.’

‘A shepherd, accustomed to number his flock, knows them from those of another, by marks which none but himself can discover.’

‘A man of a nice palate in liquors, distinguishes in the flavours of wines dif­ferences which are unnoticed by others.’

‘The ear of the musician who leads the orchestra is sensible of the least dissonance.’

‘And the words of a foreign language appear to one unaccustomed thereto, but a confusion of articulate sounds, which become afterwards distinct, by hearing them frequently repeated?’

If we maturely consider these pheno­mena, we shall find this pretended im­provement of the senses^*, which is at­tributed [Page 187]to exercise, to be very erroneous; for exercise neither changes the texture of our organs, nor adds to their delicacy. It is true that, by exercising the senses, a greater quantity of nervous fluid is de­termined into their organs, whereby their sensibility is increased: but he, who en­deavours to view minute objects for the first time, has the organ of sight equally tense with him who is accustomed to dis­tinguish them at the first glance, although he can neither see nor remark any thing. It is not therefore to the organ but to the soul which receives the sensation, that we are to attribute the cause of this phe­nomenon.

This pretended delicacy of the senses arises only from the attention which the mind gives to the smallest impressions of objects affecting it; for whether we ex­ercise our organs or not, the delicacy of the senses continues the same. But the [Page 188]mind, being attentive to the sensations it receives, gradually becomes able to dis­cern the smallest differences, which are too weak to be perceived by a single effort of the attention. Besides, it is not in the organs of sense that the soul perceives, but in itself; there the prospect of nature ex­ists. We must therefore look on sensibi­lity as a tablet, upon which are represented the images of the objects which affect us, and wherein the understanding perceives them. As these representations have parts of astronger or weaker colouring, more or less luminous, more or less distinct: so some of these^* more strongly engage the mind than others; those which are weak­ly coloured, and are the representations of very minute objects, are almost im­perceptible; such are not perceived at first sight, but must be sought for with atten­tion before they are found. If a painter perceive at the first glance the defects of a painting; if a shepherd easily distinguish his sheep; this proceeds from no other cause, than that both are accustomed to [Page 189]turn their attention to these objects more frequently than to any other. Thus a very great number of delicate sensations, re­ceived by a soul united to strong and e­lastic organs, are lost when united to or­gans destitute both of strength and vigour.

What I have said of the sensations is true in regard to ideas likewise; for it is only by long continued attention that we can make those delicate observa­tions, and acquire those refined ideas which escape the generality of men.

Thus the difference of the force and elasticity of our fibres is a new source of the diversity of minds.

Hitherto we have seen in what manner the corporeal influences the spiritual part, how the constitution of the body forms the character of the mind; but we have not yet concluded: let us make further re­searches into this subject, and endeavour to discover truths hitherto enveloped with extreme darkness.

The more we study the soul, the more we trace its progress in the exercise of its faculties, and the more we examine its operations; the more shall be forced [Page 190]to acknowledge the powerful influence of the corporeal on the intellectual part in Man.

Organization renders MAN rational or insane.

The mind undoubtedly possesses the fa­culty of thinking; and although all men were equally endowed therewith, organi­zation would not the less regulate the ex­ercise of this faculty: for thinking, when our thoughts are in regular succession, re­quires tension of the fibres; the mind ne­ver can proceed alone, but requires the concurrence of the organs to form a sound judgment of things, or to reflect. Thus depending on the senses for its unfolding, on the organic elasticity and force of the fibres for the character of its ideas; it likewise depends on the same organic elas­ticity of these organs, for the order of its thoughts and the mode of their succces­sion; this last dependency of the soul on the body is the cause of the principal di­versities in minds.

Regular thought ever requires a certain aegree of tension of the fibres; the mind can [Page 191]never proceed alone, but needs the concur­rence of our organs to form a sound judg­ment of things, or to reflect.

This principle, the importance whereof all who think justly must needs feel, now first presents itself; besides, it is so closely connected with the subject, that it re­quires to be fully explained, and to be es­tablished on the most demonstrative proofs. I therefore proceed to consider Nature in a manner never attempted before.

The mind is endued with the faculty of judging, but judges not always in the same manner; at one time its thoughts are connected with each other; at another they are without either continuance or connection; sometimes they succeed each other with rapidity, and sometimes the reverse.

Philosophers have attributed these phe­nomena to the soul, never supposing, what now appears a certain truth, that they wholly depend on the body. The mind judges not in any particular manner, but by means of some particular relations be­tween it and the disposition of our organs; this disposition determines the character of our thoughts.

[Page 192]Although ideas arise without our con­sent, and sometimes in opposition thereto, the mind always requires the assistance of the body to dispose them in succession, and determine them to some particular end.

When the body is exhausted with fa­tigue, when the head inclines forward on the breast, when the eyes are heavy and yield to the pleasing power of sleep, the blood steals through the veins with a gentle current, the sensations grow weak­er by degrees, the senses lose their viva­city, and the mind traces out faint images only, resembling the almost imperceptible contours drawn by a very light hand.

In sleep, all our faculties are in action, although the imagination appears to be the only acting power; but the sensations fol­low, and the thoughts succeed each other with rapidity and confusion, and we nei­ther compare nor are conscious of them: the mind, at that time, in appearance disengaged from matter, rambles after dif­ferent objects, and from their irregular assemblage, forms those empty images which compose our nocturnal illusions. [Page 193]On the contrary, in inflammatory fevers, when the blood rapidly circulates in the vessels, the sensations and ideas are strong­ly marked; nevertheless they succeed each other in confusion, whilst the soul neither compares nor is conscious of them. But with persons both healthy and awake, the sensations have a moderate degree of force, the ideas are distinct, the soul com­pares them, and disposes them in a regu­lar and orderly succession.

If we maturely consider these phenome­na, we shall discover their cause to consist in the different tone of the fibres, whilst asleep or awake, in a healthy or diseased state of the body. In sleep, this tone is too feeble to promote the justness of our thoughts, and the regularity of their suc­cession; in an inflammatory fever, the tone is, on the contrary, too strong: a regular succession of thoughts, therefore, always requires a certain degree of tension, or rather a moderate degree of organic elasticity.

As these ideas are too singular, these principles too new, to be received without farther confirmation, I shall proceed to [Page 194]give the clearest evidence of their truth. Man has two modes of existence, sleeping and waking; in this latter every spring of the machine is in action; in the former, those only which are allotted for the con­tinuation of the vital functions.

Sleep is essential to Man; it is the ne­cessary consequence of his constitution, and of the laws of the animal oeconomy: by these laws he passes from a sleeping to a waking state; by these laws likewise the time of waking necessarily succeeds that of repose, and both are independant of every external cause. For Man can subsist for a determinate space only, in either of these states: by continual watching, the inces­sant motion of the fibres would destroy their organic elasticity, and prevent their future reparation; so by continual sleep­ing, though the fibres are not fatigued, the nervous fluid would be gradually ex­hausted by the action of the organs of life, and would never be repaired.

The continuance of either of these two modes of existence, would therefore ne­cessarily be attended with a total cessation of vital motion.

[Page 195]At the approach of sleep, the muscles relax, the neck seems unable to support the head, the arms yield to their own weight, the senses become inactive, the whole body sinks into repose, and the blood circulates with a slow and gentle pace. By attending to the disposition of the organs of a man asleep, and to the pheno­mena accompanying it, we discover, that this state is produced by the defect of the organical elasticity of the fibres. This relaxation is even sensible to the touch, the skin of one asleep being more moist, and the fibres softer than when awake. But were this relaxation imperceptible by the senses, the simple examination of the causes of sleep will be sufficient to confirm the truth of the principle here established.

It is an incontestible fact, that every thing which impairs the organic elasticity of the fibres, occasions sleep; and that every thing which increases this elasticity prevents it. The loss of nervous fluid in coition is immediately followed by a slight drowsiness: after the conflicts of love, the vivacity of our motions is diminished, our desires are extinct, and we gradually sink into repose.

[Page 196]The loss of the same fluid by labour produces the same effect.

Though this loss of the nervous fluid be a principal cause of sleep, it is not the only one; let us repair it ever so much by fresh supplies of aliments, sleep will not be the less necessary; this may prevent it for a short time, but afterwards suffers it to return with new force. Thus the loss of nervous fluid is not alone produc­tive of it; since, not being exhausted of this fluid, Man sleeps not the less; sleep therefore is occasioned by a disposition pe­culiar to the solids; and this disposition is no other than the lassitude of the or­gans, produced by the tension of the fibres when awake, or by the reiterated extension and contraction of the muscles in motion.

Sleep therefore is caused by the diminu­tion of the organic elasticity of the solids, and by the diminution of their primitive elasticity; for it is certain, that an elastic body loses its primitive elasticity by fre­quent contraction. The fibres, after ex­treme tension, relax, and their organic elasticity being impaired, the circulation [Page 197]is slowly performed, the secretion of the nervous fluid is obstructed, as likewise its influx into the organs of sense and mo­tion; whence result a diminution of sen­sibility, a weakness, and a general languor of the sensations, desires and ideas^*.

Although all communication between the soul and the body appears interrupted during sleep, these two substances however have a constant relation one to the other. The senses are ever open to the action of external objects, and their slightest im­pressions are conveyed to the soul; but too weak to engage it, they only glance there­on without leaving any vestige behind; strong sensations only can awaken and en­gage it. These are phenomena peculiar to sleep, and proper to confirm what has been already said concerning its causes.

These truths however are supported by other phenomena. The fibres of persons greatly disposed to sleep are feeble, and it is by sleep that our existence commences. The infant, whose fibres are endued but [Page 198]with a very small degree of organic elas­ticity, sleeps continually; children, whose fibres are very weak, sleep more than they wake; in proportion as they advance in years, that is, in proportion as their fibres acquire strength and elasticity, they en­dure more easily the want of repose; wo­men, less strong and less vigorous than men, have likewise more occasion for sleep. Phlegmatic men^*, whose fibres have but a small degree of organic elasti­city, consume the half of life in that state, and people, when recovering from any disease, sleep almost continually.

Another cause is, that every thing which impairs the force of the circulation by decreasing the elasticity of the fibres, as heat, emollient liquors, and whatever be­numbs the solids, as sulphureous vapours, spirituous liquors and opium, ever pro­duces sleep.

In subjects which have died of a le­thargy, or of any sleepy disease, we find the head disordered, and the other parts sound.

[Page 199]Bonet^*, who has collected a vast number of observations of this kind, ‘found a great quantity of extravasated serosities in the brain of one who had died of a lethargy, so that the cortical substance and the meninges were covered therewith. In another subject, that had never been attacked but once with any sleepy affection, the internal part of the cerebrum was full of extravasated serosities. In others, he found scir­ruses and tumours in the cortical part of this viscus. Finally, in some that had been affected with an habitual le­thargy, the substance of the brain was found dry, and the vessels of the pia mater extremely distended with thick and grumous blood.’

These observations prove, that this con­tinual numbness is caused by the diminu­tion, or even by the total suppression of the influx of the nervous fluid into the organs of motion and sense; a natural effect of its vicious secretion, during the distension of the cortical substance of the [Page 200]brain, of the defect of the oscillatory motion of the distended meninges, of the compression of the medullary substance by the extravasated serosities, or the defect of this fluid as in a siccity of the brain. Be­sides it is well known, that the simple pressure of this viscus, after the removal of the cranium, produces sleep, by pre­venting the influx of the nervous fluid in­to the origin of the nerves, and conse­quently by weakening the organic elasti­city of the fibres, as the preceding causes^*. But the most conclusive reason is, that sleep cannot take place whilst the body is violently agitated, either by a fever, or by any violent passion, equally capable of producing a tension of the fibres.

If the relaxation of the fibres be the cause of sleep, the re-establishment of their organic elasticity by repose must be the cause of waking. This cause, which [Page 201]is necessarily deduced from the nature of things, I shall demonstrate by its pheno­mena.

On the conclusion of undisturbed sleep, the fibres insensibly become more tense, the complexion more lively, the circula­tion more quick, the impressions of ob­jects on the senses more strong, and the soul again communicates with external objects. When we have once fallen into a deep sleep, we are not awakened from it but by very lively sensations; but when the usual space of time allotted for rest is nearly expired, the least noise awakes us, and ever more easily, the nearer we are to the hour of awaking: so that the first de­gree of sleep is scarcely to be distinguish­ed from waking, and its last degree is confounded therewith. Sleep, therefore, comes on and goes off by insensible de­grees; similar, in this respect, to the ob­scurity of night, which gradually increases till it arrives at midnight darkness, and af­terwards decreases by the same gradation. Let us therefore conclude, that the fibres possess a greater degree of organic elasti­city in Man when awake than when a­sleep. [Page 202]It is then obvious, that whilst the fibres are relaxed, there is no regular se­ries of thoughts; the mind passes without any regularity over the sensations it has received, its thoughts succeed each other in confusion; and, if at any time they form a regular series, it is only whilst the fibres are tense. In the agitations of a painful dream, the thoughts are some­what regular; but in the mean time, Man is greatly disturbed, and, when he afterwards awakes, finds himself oppressed with fatigue, and wet with sweat and tears.

Thus it is only by the relaxation of the organic elasticity of our fibres, that sleep interrupts the succession of our ideas; the order of our thoughts therefore depends on the state of the body.

I imagine, the proofs already offered in support of this will be found satisfacto­rily conclusive; but that no proof may be wanting, and that the principle may be incontrovertibly established, let us examine the state of the body relatively to the suc­cession of the ideas in madmen, those liv­ing examples of the vagaries, or, if you will, of the rovings of this distempered state of human reason.

[Page 203]There are many species of madness, in every one of which the mind forms wrong judgments of things. In each spe­cies of madness, sensations and ideas of every kind are produced, but have neither order nor connexion; and in this incohe­rent succession, in this chaos of sensations and thoughts, the will acts not, but lets the images of things succeed each other in disorder. Attention not being suffi­ciently strong, the soul is not conscious of its thoughts; so that illusion is often admitted amongst, and intimately con­nected with them.

This, however, may be observed with re­spect to the several species of madness; that state of the soul, which is accidental in the one, is natural and constant in the other sorts: but all equally result from an ina­bility to attend; this inability I shall de­monstrate to be wholly dependent on the constitution of the body.

Physiologists have sought in dead ani­mals the causes of this disordered state of the soul in living animals, as if it proceeded from the unnatural confor­mation of some organ, which must ne­cessarily [Page 204]always exist, never dreaming that it might be occasioned by some change in the organic elasticity of the solids, the only principle by which these phenomena can be explained. A striking example of the ill-success of most physiological en­quiries, and a proof that our efforts to dis­cover truth serve often to mislead us, and to remove us to a great distance from it!

By comparing the state of the body of one that died in perfect enjoyment of rea­son, with that of one who died in a state of madness, we shall undoubtedly disco­ver many considerable differences; such as the distension of the vessels of the me­ninges; the inflammation of these mem­branes; the extravasation of lymph into the sinuses of the brain; the siccity of this viscus, and of the origin of the nerves; appearances commonly seen in the bodies of the latter, but never in those of the former. This difference, which is here supposed to be the cause, is only the ef­fect. Considered as the effect, it may conduct us to the knowledge of the true principle; but in our enquiries we shall proceed with greater success, by compar­ing [Page 205]the state of the solids of a man in perfect reason, with that of the solids of one who has lost it.

The different species of madness may be reduced to two; which are to be dis­tinguished not by those vagaries of reason which are common to both, but by the character of the thoughts; they are de­signed under two general denominations; furious madness, when the thoughts are daring, and the emotions of the soul vehe­ment; insanity or idiotism, when the emo­tions of the soul and the thoughts are weakly expressed.

There is a rigidity of the nervous sys­tem, when the rovings of the soul are at­tended with fury, as in frenzy, inflamma­tory fevers, drunkenness, and the hysteric affection; there is a debilitation thereof, when the same rovings are indicated in a tranquil and languid manner, as in insa­nity, dotage, and in that melancholy madness, which is occasioned by the use of narcotics. Every one may be convinced of this, by simply inspecting a body in these different states, and by examining the phenomena.

[Page 206]With regard to that affection of the mind which is produced by drunkenness, it is obvious, that spirituous liquors are peculiarly adapted to produce a rigidity in the fibres.

The saline particles with which these liquors are impregnated, and the spirits with which they abound, when received into the stomach, first irritate its mem­branes, and, being conveyed into the in­testines, irritate their coats: this irrita­tion is immediately followed by a spasm of these organs, propagated through­out the body, by the correspondence of the nervous system which affects every part, but more especially the meninges.

This violent tension of the meninges is presently after produced in a more direct manner: the salts and the spirits gradually pass into the fluids, and, being conveyed to the brain with the blood, increase the tension of its membranes, and the circula­tion is rendered more impetuous. This violent spasm, at intervals, compresses the cavity of the nerves, and interrupts, in whole or in part, the perflux of their fluid: [Page 207]hence proceed those irregular and convul­sive motions of the muscles, that stagger­ing and total loss of sense and motion, observed in persons who have died in a state of inebriation. By comparing the tone of the solids of a drunkard, with that of the solids of a temperate person, we find the fibres moderately tense in the latter, and extremely so in the former. In drunk­enness, the countenance appears inflamed, the eyes red and fiery, the vessels of the face distended, the limbs at first are flexi­ble, afterwards they are stiff and con­vulsed; the regularity of muscular motion is destroyed, the body is unstable, the senses are dull, the sight is troubled, and the objects looked upon seem to waver. Here, if we may judge by the senses, is an ex­treme tension of the fibres, which very nearly approaches to rigidity, and this ri­gidity is proved on the testimony of facts.

If this spasm be so visible in the strong and gross organs, what must it be in the fibres of the meninges, which are incom­parably more delicate and more sensible!

The effects, which are produced in the solids in drunkenness, by the irritating [Page 208]and caustic particles of the liquors which have been drunk, are produced in fevers in a much higher degree^*. In the hysteric passion, the spasm of the nervous system is ever considerably greater than in fevers; but this spasm arises not instantaneously: at first, a numbness is felt about the hips and loins, the abdomen and stomach are distended, a painful oppression is felt at the breast, anxieties at the heart, a gene­ral numbness and shivering of the whole body, violent pain is felt in the head, a tension in the forehead and temples, the sight is troubled, involuntary tears flow, respiration is difficult, the navel is drawn inwards, the heart palpitates, the pulse is hard and unequal, the extremities become cold, the oesophagus is closed, respiration interrupted, the voice dies away, the mouth is convulsed, the arms and hands are violently contracted, the body is con­torted, and every limb agitated with con­vulsive motions.

[Page 209]Finally, if we carefully examine the body of a madman, we shall find the fibres to be tense, the pulse extremely hard and unequal, the eyes fiery, as in rage, and the body affected with convul­sive motions, more or less strong, accord­ing to the force of the frenzy, but less ap­parent than in the diseases mentioned above; nor is their fury so extreme. This extraordinary vigour, these impe­tuous motions, these terrible convulsions which accompany drunkenness, the hys­teric passion, frenzy, and inflammatory fevers, are evidently the effects of the violent influx of the nervous fluid into the muscles, occasioned by the violent and ir­regular contraction of the irritated me­ninges, That there is a spasm, a rigidity in every case of this kind, is obvious from the attendant symptoms, and from the state of the organs of subjects which have not survived this disorder.

In the dissection of hysteric women, we almost always find every part of the body unaffected, the organs of generation [Page 210]excepted^*: ‘In some the testes have been found distended with a thick and yel­lowish liquor, of a very offensive smell; in others the testes, spermatic vessels, and vessels of the uterus, were distended with a whitish lymph, viscous and of a very pungent smell; in others, were found polypous excrescences adjoining to the uterus; the uterus itself has been observed nearly filled with a fluid, in colour as if tinged with saffron and cor­rupted; sometimes the membranes have been inflamed and distended with grumous and thick blood.’

From the symptoms accompanying this disease, it is evident, that the spasm of the nervous system, occasioning the dis­order of the functions of the body, begins at the uterus, which is irritated by the corrupted liquor contained in the sper­matic vessels, and is afterwards gradually propagated by the nerves to the other parts, [Page 211]even to the membranes of the brain, where it sometimes leaves visible marks of irri­tation.

‘In subjects which have died of in­flammatory fevers or of madness, many ramifications of the meninges have been found distended, and these membranes themselves inflamed^*; in others have been discovered many sanious serosities in the ventricles of the brain, many vesicles, or rather varices full of sanious lymph, and the plexus choroides in­flamed: in others the vessels of the me­ninges were livid and full of thick blood, many serosities were found in the ventri­cles of the brain, and a livid polypous concretion in the sinus falci-formis; the other parts of the body were sound, the brain alone being affected.’ This dilatation of the blood vessels, these va­rices, these distensions, these extravasa­tions of sanious serosities, and inflamma­tions of the membranes of the brain, are evidently the effects of violent, irregular, [Page 212]and obstructed circulation, occasioned by the spasm of the nervous system, and of the solids in general. For when a part is affected with a spasm, the vessels of which it is composed are violently contracted; and as the coats of the arteries are more strong than those of the veins, so much the more they resist their contraction; the blood continues to flow on to that part with ease, but in its return is ob­structed; whereby it accumulates in these vessels, and excessively distends them: hence these inflammations, distensions and varices. When the distension is extreme, the vessels permit their contained fluid to permeate their coats: hence those extra­vasations of the lymph, blood, and those polypous excrescences which proceed therefrom. Finally, if we observe that caustic acrids, as the hyosciamum, solanum verum, and generally every thing that ir­ritates the nerves and renders them rigid, either taken internally or applied outward­ly, produce the most terrible delirium and madness; whilst lenients and antispasmodic medicines restore reason, we shall be con­vinced, that this perturbed state of the [Page 213]mind is wholly produced by the spasm of the nervous system, but more especially by that of the membranes of the brain. Hence it is evident, that furious madness proceeds from a rigidity of the fibres; I shall now shew that insanity or idiotism is occasioned by their relaxation.

Insanity often succeeds madness, and that instantaneously; this phenomenon is very natural, as the violent tension of the fibres must be followed by their relaxation: when this debilitation is considerable, and the organic elasticity of the fibres is so greatly impaired, that it requires some considerable time before it can be restored, the mind recovers not the tone adapted for reason; it only changes the species of its folly. This is more particularly observed in inflammatory fevers, where furious madness opens the disease, and idiotism concludes it. Whilst the nerves are con­vulsed, and the circulation is vehement, Man acts with violence, his ideas are con­fused, he loses all knowledge, and utters, with a furious aspect, incoherent expres­sions: but when the morbid humours have taken another course, when the black [Page 214]poison which occasions his disease is dis­charged from his vessels; weakened by the violence his transports, he remains a long time destitute of strength, de­prived of reason, insensible either of the evil or danger of his condition, and is reduced to a state of infancy, which is of so much the longer duration, andthe debi­litation of the elasticity of his fibres is more extreme; for in these cases the ef­fect is ever equal to the cause.

To the foregoing may be added the analogy between the disposition of the soul and body during sleep, and the dis­position of these two substances during in­sanity. For this state of the soul, whilst Man is awake, perfectly corresponds to that whilst Man is asleep; the succession of sensations is the same; the exercise of thinking, and the action of the organs are the same likewise; in both, the fibres are relaxed, and the circulation languid: whence it appears, that these two states have similar causes.

This kind of insanity is oftentimes produced by excessive study, by violent passions, by a considerable loss of semen, [Page 215]and by every thing which debilitates the organic elasticity of the fibres. This is confirmed by comparative anatomy: for the state of dotage, that is, when the sensations and ideas are combined without order, is precisely the same as when the body is feeble, the strength is exhausted, and the organs are inelastic. It is there­fore obvious, that this alienation of mind is the effect of the extreme impairing of the organic elasticity of our solids

Furious madness proceeds from the rigidity of the fibres; idiotism or insanity from their relaxation; and the slate adapted for reason from their moderate elasticity: such are the secret causes of the order which obtains in our thoughts. Hence it appears, that a greater or less degree of tension of the fibres can make a man either rational or insane. Reason and madness must therefore depend on the mechanism of the body, and not in the least on the soul, as philo­sophers have falsely supposed.

Having contemplated these rovings of the soul, and discovered their causes in the different tones of the fibres, let us proceed to assign the reason of these phe­nomena.

[Page 216]A regular series of thoughts ever re­quires, in order to its formation, that the mind be intent on the object of its judgments; this intenseness of the mind is ever accompanied by that of the body. During meditation, the pulse beats more strongly than when we do not meditate, and so much the more strongly, as the soul is the more deeply engaged in medita­tion. Thus in cataleptics, whilst the soul is involved in the most profound re­flections, the blood circulates with greater freedom and force, the complexion be­comes more lively, respiration more free, and every function of the body is more perfectly performed. During meditation the whole body is violently tense, but par­ticularly the plexus nervosi, and the mem­branes of the brain.

Too great or too long application in­creases this tension, even so far as to ex­cite a stupor in the head, and kindle up a fever in the veins: studious persons fre­quently experience this, I myself have, many times.

The soul, during meditation, not only af­fects the body with a degree of tension, but [Page 217]without its concurrence cannot operate alone. In chronic diseases, during a state of convalescence, and after a considerable loss of semen, we can neither reflect nor meditate, whatever efforts we make; we think very little, and our ideas are vague and unconnected. Even immediately af­ter profound meditation, the mind being fatigued, indulges itself in roving, al­though the will oppose; we indeed con­tinue to think, but our thoughts are alto­gether irregular; we remain awake, but experience the effects of sleep; imagina­tion traces the same airy semblances, the same fugitive shades as during sleep.

No regular series of thoughts can be formed without a tension of the fibres: this tension has fixed bounds, determined limits, beyond which the succession of our ideas cannot proceed. When the fibres are too tense, as in drunkenness, in fevers, and in violent head aches, let us ever so much attempt to reflect, all our efforts are vain, the soul is either in a delirium or in a stupor. It has been proved, that in regular thought the understanding^* is sub­ject [Page 218]to the will; that this exercise of rea­son requires a certain tone of the solids; and that the tone of the solids necessary to reason has a certain extent: this tone, therefore, must be constantly existent in Man, whilst his organs are obedient to the will; but is not found either in a state of rigidity or relaxation, two states of the fibres which have this in common, that they both equally free the body from subjection to the will.

If we notice the power which certain aliments, fruits, and liquors have on the body, we shall be convinced that it is su­perior, or at least equal to that of the soul over the material substance to which it is united. Again, if we compare the empire of the different faculties of the soul over the body, we shall be convin­ced^*, that the power of sensibility is much greater than that of the will, and incomparably more so than that of the un­derstanding or imagination. That of sen­sibility and imagination is universal; that is, it influences both the muscular fibres and their fibrillae, the organs of sense and [Page 219]motion; whilst that of the will is restrain­ed to the latter of these only. But none of these faculties has any power over the body, but by the nervous fluid; when this is deficient, or when it has lost its energy, or even when the elasticity of the fibres is impaired, it is obvious, that the power of the will is at an end. Even when this fluid is violently impelled into the muscular fibres, either by sensibilty or by some other cause, with greater im­petuosity than the will can impel it; it is evident, that the rigidity is not removed, but confirmed thereby, if it proceed from a violent influx of the nervous fluid into the fibres.

Hence the reason why the violent passi­ons, as rage, fear, terror, affect us with a kind of momentary madness; why the efforts we make to reflect, when fatigued by meditation, only serve to increase our inability to think; in a word, why the rigidity and total relaxation of the solids deprive the soul of the free exercise of its faculties, and are the causes of madness, the degree and force whereof is proportioned to that of their principle.

[Page 220]Let us therefore conclude, that as the mind cannot act alone, it ever requires the concurrence of the corporeal organs to reflect and meditate, and that the unfolding of its faculties entirely depends upon organzation.

I have now only to offer a few observa­tions on the subsequent phenomena, to confirm what has been said on the same subject elsewhere^*. Certain hypochon­driacs see visions at mid-day, and with their eyes open: some fancy they behold a continued series of phantoms and hide­ous spectres, rapidly succeeding each other; others, a series of agreeable objects, flit­ting shades, female forms, magnificent scenes, which offer themselves in succes­sion, and are seen like objects really ex­isting; so that the deception of these vi­sionary representations is so strong, that they believe them to be realities.

When speaking of the colourings which the sentiments of the soul communicate to objects, and of the illusions of the passi­ons [Page 221]analogous to the facts related above, I observed, that physiologists had attributed these phenomena to the nervous fluid; and that, to account for it, they had imagin­ed, ‘that this fluid, which is naturally subject to the empire of the soul, be­comes its superior in these affections; that in the organ of sight particularly, it assumes every successive modification representative of objects, which had before affected it.’ I demonstrated, that physiologists improperly confound the operations of the senses with those of the mind; I likewise proved this phenome­non to be very simple, and only mysterious from our misapprehension of it. I ob­serve now, as I did then, that these visions of hypochondriacs are only sensations re­newed from the memory, the empty phan­toms of a soul violently agitated, wholly engrossed and misled by its pleasures or its pains, and unable to return within it­self to examine objects.

I have already proved, that the soul, when strongly affected by any object, is blind to every other, it being no longer able to attend thereto; I shall now offer a physical reason of this phenomenon.

[Page 222]It is only by attention, that we can dis­tinguish in the soul the real impressions of things from sensations re-produced. Be­sides, the presence of mind necessary to reflection, requires in the fibres a certain de­gree of tension, the medium between rigi­dity and relaxation. In inflammatory fe­vers, and in the hypochondriac disease, there is the same rigidity as in the inflam­mation of the stomach, contracted by the use of some acrid aliment, or by poison: for the irritation of this viscus affects the whole nervous system, and more especially the membranes of the brain. In all these cases, reason is extinct; for the will has no longer any power over the organs, as has been already shewn. Thus, aban­doned to itself, the mind employs itself in reviewing the objects which formerly af­fected it; but wanting the attention ne­cessary to discern whether their image be re-produced or not, it mistakenly imagines them present, and really existing.

When the spasm ceases, the mind in­stantly recovers its reason, these imaginary objects disappear, the deception ceases, the patient finds himself in his chamber, [Page 223]surrounded by his disconsolate friends, and relates to them the subject of his visions.

The same effects which are produced by acrid humours on the body in severs, and by irritating aliments in the inflammation of the stomach, are likewise produced by an inflamed imagination, and by violent passions; examples, which confirm this, daily occur to our observation.

When the soul is engrossed by any vio­lent passion, when the imagination forms a lively picture of the charms of a favou­rite object, represents it as the idol of the heart, adorns it with every attractive grace, and suffers it to make a deep impression on the mind; by degrees the charms, in which we have cloathed and decked it, dazzle the sight, and impose even on our­selves: then wholly engaged thereby, we are insensible to every other object, and misled fo these phantoms, we take our visions for realities.

Thus, in the extreme anxieties of a soul tormented by remorse, the guilty wretch continually revolves in his mind every crime he has committed, and re­mains a miserable victim to despair. Should [Page 224]sleep close his eyes; his sleep is only a frightful delirium, the consciousness of his crimes preys upon his heart, and terrifies him with horrid visions. He dreams he hears the groans of those he has de­stroyed, thinks he sees their ghosts rising from their tombs, and imprecating the justice of heaven on him; the darkness of hell covers the face of the earth, the furies hiss in his ears, shake their torches at him, and pursue and haunt him wherever he goes; devils, fiends, every moniter in fable beset his soul; harrassed with these horrible visions, the wretch awakes in affright, vents loud cries, starts back with horror at the ap­proach of his friends, whom now he knows not, and clasps the next thing he finds in his arms, and fancies he clings to the altar.

Thus it is that the passions produce visi­ons and trances; thus it is that enthusiasm is changed into a delirium, and thus it is that fanatic minds sometimes fancy them­selves inspired.

This discourse on the succession of our ideas, and the order which obtains in our [Page 225]thoughts, recalls me to the point from whence I first set out. I then proved that the depth, the justness and sublimity of ideas, required fibres strong and greatly elastic, and that these characters of our ideas varied together with the organization: but the different degrees of the strength and elasticity of these organs in different individuals, which at first appeared of so little consequence, produce other very surprising effects. This principle, simple as it is, abounds in consequences; it is this which enables us to discover truths, hitherto concealed from the learned, and involved in profound darkness. Let us endeavour to draw from this hidden source some additional knowledge, which may throw light on some very obscure subjects, and scatter flowers over the thorny paths of philosophy.

Organization renders Imagination the predo­minant Character of the MIND.

The exercise of regular thought is to the mind, what voluntary motion is to the body; that is, a state of constraint which [Page 226]the soul commonly yields to with reluc­tance, and ever endures with pain.

If we follow the mind in its operations, we shall observe, that when abandoned to its own activity, it acts without rule and without method; it never acts with order, but when necessity^* obliges it thereto, and returns to its former state immediately, when freed from restraint. What renders the regular exercise of thought more fatiguing than the irregular, is the attention which it requires; the dif­ficulty of fixing objects in the mind, in order to consider them^† without distrac­tion, and the efforts which are necessary to discern their different relations; efforts so much the more painful as the objects happen to be naturally volatile, and fall not within the cognizance of the senses. But what renders these efforts painful, is that tension of the fibres which this in­tenseness of the mind requires; for the tension of the fibres ever produces in the soul an unpleasing sentiment more or less [Page 227]strong, but ever proportionate to its force. We must therefore constantly recur to phy­sical causes, to account for these phenomena of the mind.

By following the mind in its operations, it is easy to discover, that when it ceases to consider objects attentively, it no longer judges of their true relations; in this case thought becomes imagination. Thus, of all the sciences, geometry requires the least aid from imagination, as it continually fixes the attention on one particular ob­ject^*.

I have demonstrated, that regular thought fatigues the mind much more^†, and much sooner than revery; I have likewise shewn, that when the mind is fatigued, it no longer fixes upon any object, and ceases to consider attentively^‡; I have shewn, [Page 228]that the attention of the mind is ever pro­portionate^* to the strength and organic elasticity of the fibres. Whence let us conclude, that a soul united to a delicate and feeble body must possess more imagination than judgment.

The transition from reason to imagina­tion is very easy. If the mind, during reflection, be distracted by any sensation, it loses sight of its objects, is engaged by some analogous relation, and wanders from one to another, till it entirely loses its first engagement; it at length perceives itself bewildered in the labyrinths of imagination, even whilst it fancies it­self attentively pursuing its former re­flections. The greater the sensibility, the more difficult it is to prevent these wanderings: whence it follows, that the Man whose organs are delicate and greatly sensible must possess more imagination than judgment.

If the transition from reason to imagi­nation be very easy, it is likewise very [Page 229]natural. Whatever our thoughts may be' some secret attractive, some hidden charm, recalls the mind to its favourite subject. The soul, ever delighted with pleasing sentiments, resigns itself wholly thereto, and its natural love of happiness prompts it to perpetuate the pleasure it takes there­in. The mind thus relishing those pleasures, wishes to increase them; where­fore it successively occupies itself in exa­mining, one after another, all the agreea­ble objects which are in any way connec­ted with those which affect it with de­light, and thus thought becomes imagi­nation. Man therefore has perpetual need to be on his guard against these wanderings, and the more so in proportion to his greater share of sensibility; for in this case the at­attraction of pleasure is most powerful. In this respect therefore, the soul which is united to very sensible and elastic organs, pos­sesses more of imagination than of judgment.

Organization characterises the THOUGHTS.

Organization not only determines our aptitude either for imagination or for [Page 230]judgment, but also often forms the cha­racter of our thoughts.

When the exercise of the understand­ing is wholly imagination, the nature of its images and ideas is ever determined^* by that of the sensation or sentiment, then affecting the mind. If this sentiment or sensation be agreeable, there is a series of pleasing illusions and agreeable images: if painful, there is a succession of sad and hideous representations. The same phe­nomenon is also evident during sleep: our dreams are pleasing or terrifying, accord­ing to the sensations we then experience.

If we take a retrospective view of what we have said concerning the succession of our ideas, when speaking of the exercise of our mental faculties, we shall find this phenomenon very simple. The mind, if left to itself, ever proceeds by analogies: the thoughts therefore must be gay, when the soul is affected with pleasure, and sad when affected with pain.

[Page 231]The impressions received by the organs of the body are conveyed to the soul, fix there, and serve as a point of departure, from whence it sets out when it commen­ces its future operations; from this time forwards it is engaged by analogous images and analogous thoughts only.

And as the soul ever perceives the dis­position of the body during sleep, although it appears to be then freed from its sub­jection to the senses; the same analogy must be observed in man asleep, as when awake. Hence the reason why the nature of dreams is ever analogous to the state of the body, and to the sensation then af­fecting the mind. Hence too, the reason why, when the sensation is agreeable, we enjoy during sleep a series of pleasing de­ceptions and agreeable images; but, when it is painful, are terrified with dismal thoughts and frightful illusions.

What has been said above concerning the imagination, is properly applicable to irregular thought only; its regular pro­ductions require the same physical dispo­sition which reason does.

The mind must compare and combine its sensations and its thoughts in many dif­ferent [Page 232]shapes, to form new productions therefrom; this requires attention, and consequently force and elasticity in the fibres. Thus imagination is weakened by degrees, together with the organic elasticity of the fibres: in proportion as they become more lax or more rigid, the mind cannot compare or combine its sensations, and becomes inac­tive; even so far as to be no longer able ei­ther to imagine or to invent; it then ceases to draw consequences from principles, and only acts by the aid of the senses.

Nevertheless, if regular imagination re­quires the elasticity of our organs, it re­quires it in a less degree than reason; for its objects are neither necessarily depen­dant on each other, nor closely connected its productions are only detached parts, where the mind has nothing to do but to weave them into one tissue. Finally, be­cause their connection depends not on the combination of a great number of thoughts or ideas which are naturally profound and difficult to be investigated, as those of reason commonly are; a single stroke of the pencil shall frequently serve to con­nect the parts of which the group is to be [Page 233]composed. And although regular imagi­nation may be a state of constraint like reason, it nevertheless fatigues the soul much less; for imagination has ever the choice of its subjects, and this choice is ever directed towards agreeable objects; whilst reason, ever tied down to follow nature, must needs frequently find an irksomeness from painful researches and dry reflections, and is ever busied in a disgustful employ­ment. Imagination therefore not only re­quires less attention than reason, but also possesses many pleasing attractives besides.

Imagination requires less force of the or­gans than reason, but a greater share of organic elasticity of the fibres, or rather a greater share of sensibility. For it is not always by a careful examination of ob­jects, nor by a series of many successive combinations, that the imagination forms new productions: the most happy strokes of fancy often present themselves to the mind spontaneously, when we least think, and are never the fruit of pains or plod­ding. It is therefore only by vaiously combining objects, by leaving (if I may be allowed the expression) the mind to [Page 234]rove at will, and by employing no more attention than is necessary to collect the result of its thoughts, and to se­lect therefrom such as are for its pur­pose. The greater our sensibility, the more liable we are to distraction, the more affected by analogies, the less at­tached to material objects, and the more capable of those happy, but fortuitous combinations, the true source of inge­nious sallies, and of the noblest produc­tions of the human mind.

Thus therefore men who have but lit­tle sensibility, and are of robust organs, can possess but a small share of imagina­tion: men, who are but little sensible, and yet delicate, must possess more. They, who are feeble and of great sensibility, yet greater: and they who are extremely vigorous and extremely sensible, most of all. Eager to rise above the sphere of the senses, these can alone soar above this low world, and with a bold wing traversing the boundless tracts of aether transport themselves to worlds unexplored before.

I have proved, that reason is not es­sential to the soul, and that the imagina­tion [Page 235]depends on the elasticity and force of the fibres, I shall now demonstrate, that remembrance and recollection are modes of the soul's existence, and wholly depen­dent on organization.

Remembrance and Recollection dependent on Organization.

Memory is almost always confounded with remembrance and recollection, qua­lities very different, and which ought to be carefully distinguished^* Memory, or the faculty of retaining our sensations and ideas, is peculiar to the soul, and inde­pendent of every physical cause: but remem­brance and recollection (the one where­of is the faculty of discerning our sensati­ons and ideas, when re-produced to be those which we have before received; and the o­ther, that of re-producing them at will) al­though intellectual powers, nevertheless wholly depend on organization.

[Page 236]Acute diseases of a long continuance ever impair both remembrance and recol­lection; chronic diseases are ever accom­panied with the same phenomenon; but more especially the hernia spinalis, when the tumor is opened, and even still more than this, those sleepy diseases which ensue from a considerable loss of semen^*. Great drinkers, apoplectics, those unfortunate per­sons who have undergone the operation of the trepan, those who have been covered after hanging, frequently pass the residue of life, unable either to remember or to recollect.

The microcephali, whose brain is of smaller dimensions than common, are ge­nerally destitute of these faculties.

Finally, in the history of the academy of sciences of Paris, Année 1701, pag. 57. we find the case of a child, eight years of age, that lost its^† memory by the ex­cessive heats of summer, and never reco­vered it whilst the heats continued.

[Page 237]Since the influence of the body on the soul has fixed and constant relations, the de­cay and loss of remembrance or recollection are therefore produced by causes common to every instance abovementioned. By what these cases have in common, it clearly ap­pears, that the cause of this decay, and loss of these powers, is only the diminu­tion of the organic elasticity of the ner­vous system, but more especially of the membranes of the brain; a diminution common to every subject here noticed, but produced in different ways. In the one, by a defect of the nervous fluid, as in microcephali, and those who have been ex­hausted by immoderate coition: in others, by a violent tension of the fibres, as in apoplectics, those who have been recalled to life after hanging, and those who have under gone the operation of the trepan: in others, by these two causes united, as in persons affected with acute or chronic diseases.

We shall be fully convinced of this truth, if we consider, that every thing which im­pairs the tone of the solids, either by vi­tiating the secretion of the nervous fluid in the brain, or restraining its action, pro­duces [Page 238]the same effect. The immoderate use of cooling liquors, spirits, opium, hy­osciamum, and other narcotics, long and profound sadness, fear, terror, and every other violent passion of the soul, too long continued watching, and too profound me­ditation, all which are adapted to destroy the elasticity of the fibres, occasion the loss of remembrance and recollection. Fi­nally, the decay, and even the loss of these powers, are often occasioned by ex­cessive heat; in this case, it is visibly pro­duced by the diminution of organic elasti­city. Every thing concurs to establish the loss of elasticity, as the cause of this phe­nomenon, as I have observed, in collect­ing the different observations made upon this subject, and reducing to fixed points their numerous variations.

If more proofs were required, I would here repeat what has been said elsewhere concerning the order of our thoughts. On the approach of sleep, and at the close of wearisome meditation, when the fibres relax and the circulation is languid, when the senses are inactive and every organ is at rest, the soul appears to be then detached from the body, and wanders without any [Page 239]scope; remembrance is lost, we recollect nothing, not even things which are the most familiar. When sleep closes the eyes, objects which affect us whilst awake are retraced in the mind, but the mind remembers them not, and this forgetful­ness is so much the more extreme as the sleep is more profound, that is, as the fi­bres are more relaxed; the mind recovers not these powers, till the elasticity of the fibres is re-established by repose.

But if the loss of remembrance and re­collection be often produced by the relax­ation of the fibres; it is sometimes occasi­oned by their rigidity. In inflammatory fevers, in drunkenness, nothing is remem­bered, nothing recollected. How fre­quently are seen persons when affected with either of these, that know not their friends, children, wives, and even forget their own name! How many have been reduced to the same miserable state from the irritation of the meninges by splinters of the crani­um, or by some extraneous body!

Remembrance and recollection, therefore, require a moderate degree of tension of the fibres, as does the regular exercise of thought. [Page 240]The reason of this phenomenon is easily comprehended. Memory is a passive fa­culty; but remembrance and recollection are the^* results of our several intellectual faculties combined. The one is the state of reflecting on the sensations and the ideas deposited in the memory: the other is a state of intenseness, by which the soul forces itself to recall these sensations and these ideas. Remembrance and recollec­tion therefore of necessity require atten­tion, and consequently a moderate degree of organic elasticity in the fibres. It is therefore obvious, that when the subjects of our observations have not the power of rendering the fibres tense, the mind is de­void of these powers.

Hence we must conclude, that remem­brance and recollection are determined by the tone of the solids, and even depend on organization.

Hitherto I have shown how the differ­ent degrees of the elasticity of the fibres contribute to the diversity of minds, and [Page 241]how this mechanism explains these phe­nomena, reconciles them to Nature, if I may be allowed the expression, and divests them of the marvellous; this cause, how­ever simple it may appear, produces ma­ny other very surprising effects.

Organization renders MAN intelligent or stupid.

Penetration, that noble faculty of the mind, by which we discern truth amidst the darkness surrounding it, by which we discover the most remote relations of things, depends on the tone of the fibres, and on the state of the body, equally with remembrance and recollection; for being wholly owing to the capacity of the mind^*, and to the number of ideas and sensations, it consequently must depend on the number of the senses, and on their good organization. ‘Nevertheless the senses of an idiot appear sound and well con­stituted; he has likewise, as other per­sons have, sensations of every kind, [Page 242]and he arranges them in the same order, when he acts like others: but he has but very few ideas, and is deficient in judgment and penetration.’

Penetration depends on the number of the senses, and their good organization; but de­pends not wholly thereon. To discover the relations of things, it is not sufficient to have a great number of sensations, there is also necessary the power of calling them to mind when occasion requires. With­out this faculty, the sensations deposited in the memory would be useless; without it, the mind could compare its present sensa­tions only, all its judgments would be de­termined by the senses, and Man no longer act as Man, but as the most stupid of beasts. Besides, the number of the senses and their good organization, penetration likewise requires the same elasticity and force in the fibres as recollection.

But even this will not suffice. To dis­cover the relations of things, the mind must compare them in their different as­pects, and variously combine them. Ex­cept this, admitting every other qualifica­tion, the best organized senses, the most [Page 243]ardent desire of attaining perfection; yet so long as Man continues unable to com­bine his sensations, it will be impossible for him to acquire knowledge. Penetra­tion therefore requires the same organic elas­ticity of the fibres as reflection.

Every man has a certain number of sensations, but all men have not equally the power of recalling, comparing, com­bining, and arranging them; qualities in­dispensibly necessary to the discovery of concealed relations. These qualities idiots have not; and this inability to recollect or reflect, is to be wholly attributed to the state of their organs.

If we compare the body of an idiot with the body of a rational person, we shall find many considerable diversities between them. The most conspicuous is the small dimensions of the cerebrum. Microcephali ^* are idiots by nature; they have neither conception nor judgment: on the contra­ry, macrocephali are very ingenious.

Another difference is the bulk of the body, in comparison of the size of the [Page 244]head. Extremely large and fat persons, are commonly but a small remove from stupidity; whilst small and lean persons are generally the reverse.

But all idiots are not so by nature; some gradually arrive at that state, the most in­genious equally with others. Acute dis­eases of long continuance^*, and likewise chronic diseases, impair the penetration. The considerable loss of nervous fluid, ei­ther by coition, by its discharge from the tumor of the hernia spinalis, or by exten­sive exercise, produces the same effects. Great drinkers, apoplectics, they who have undergone the operation of the tre­pan, they who have been recovered after hanging, remain very long without con­ception and without judgment.

Let us attend to the reason of these phe­nomena.

Microcephali are idiots, macrocephali ve­ry sagacious. But if penetration be ever proportionate to the dimensions of the brain, it is not from any particular orga­nization of this viscus, as some have ima­gined. [Page 245]The brain is only an organ of se­cretion, and is without relation to the soul, except by its secreting a greater or less quantity of the nervous fluid; and as its volume might more or less obstruct the ori­gin of the nerves, by compressing the mem­branes which surround it; it is only in these respects, that the brain can influence penetration.

It has been already shewn, that the ex­ercise of regular thought, such as is ne­cessary to penetration, requires a tension of the fibres, particularly of those of the meninges. This tension, this augmenta­tion of the organic elasticity of the solids, arises from the immediate influx of the nervous fluid impelled into these organs by the will. The more this fluid, so im­mediately subject to the soul in voluntary motion^*, abounds, the more strongly Man can apply his mind to reflection, and the longer continue it: for the power of the will on our organs, never prevails so far as to render them rigid. Hence it is [Page 246]evident, that microcephali, who are not abundantly supplied therewith, must ne­cessarily be stupid; and that macrocephali, who possess it in great abundance, must be perfectly the reverse. Hence it is, that large and very fat persons have in general but little sagacity; for the bulk of the body continually increases, and the size of the brain continues the same. This enor­mous bulk of body, compared to the di­mension of the brain, places them in the same class with microcephali.

This inability in microcephali, and in those who are extremely fat, to increase the organic elasticity of their fibres, often destroys the penetration of the most saga­cious. To this is owing that stupidity which affects those who have been reco­vered after hanging, apoplectics, those who have suffered the operation of the trepan, and hard drinkers. It is this, like­wise, which, after acute and chronic dis­eases, deprives men of the faculty of con­ception, and reduces them to a state of infancy.

Hence is the reason that, when an in­flammatory fever has consumed the ner­vous [Page 247]fluid, and fatigued our organs by vio­lent and precipitate motions, the mind is affected with a stupor, all its faculties are disordered, and all knowledge lost: this returns not, but in proportion as the body acquires strength, and arrives not to its former perfect state, till the body has en­tirely recovered its former vigour.

Hence the reason why the violent passi­ons, profound sadness, and narcotics, pro­duce a kind of momentary stupidity.

Hence the reason why some persons have become stupid, by imitating too affi­diously the gestures of folly.

It is therefore evident, that the extreme impair of the organic elasticity of the fibres generates stupidity, and that the penetration of every individual depends on his orga­nization.

Organization renders MAN sagacious or dull, sedate or volatile, and the Judgment, clear or confused.

Nature has greatly varied the degrees of the delicacy and vivacity of minds. Sa­gacity, that quickness of understanding, [Page 248]in discerning the reason of things, that admirable faculty of comprehending at once a multitude of objects, or rather of re­viewing them with rapidity, and penetrat­ing in an instant the most remote rela­tions, observes not the same gradation as penetration. This increases and decays by insensible degrees; the other has no progression, but has its existence confined, as it were, to an indivisible point.

Sagacity consists in readily discovering remote relations. Thus, besides the num­ber and order of our sensations and ideas necessary to discover those relations, it re­quires quick apprehension; hence, not only the same physical disposition is ne­cessary as in penetration, that is, force and organic elasticity of the fibres, but al­so the most perfect degree of this elastici­ty, or which is the same thing, that degree which is best adapted to second the acti­vity of the will: for the exercise of the understanding in penetration is voluntary. The regular exercise of thought, requires a certain organic tone of the fibres; but this tone is not limited to one particular point, it has a certain extent contained [Page 249]between the opposite extremes of relaxa­tion and rigidity. Madness and stupidity are produced by the extremes, wisdom holds the middle station, and its various degrees occupy the whole interval between them: there are therefore different de­grees in this intermediate space, in every one of which the soul may possess pene­tration. It is in that degree of elasticity, where the fibres have a greater aptitude to yield obedience to the will, that the dis­position to sagacity consists. Thus the abundance of nervous fluid ^*, the primitive elasticity of the fibres, and that degree where the equilibrium between these two powers is most perfect, must be the principle of saga­city, of invention, of that divine enthusiasm which animates genius, and distinguishes those who possess it from the herd of common wits. [Page 250]Sagacity therefore falls to the lot of those who are endued both with vigour and sen­sibility. These are the qualities which alone actuate those towering minds which soar to the first principles of science, and rapidly rush to the goal; whilst others lag far behind, and advance with slow and tardy steps.

In proportion as this equilibrium between these two powers is destroyed, the mind necessarily loses its sagacity; but in a diffe­rent manner; if the balance be in favour of the solids, if the fibres be either too lax or too rigid, the mind is less apt to recall the sensations and ideas deposited in the memory, or to compare them, and less readily discovers their remote relations. The mind is therefore less active, takes up longer time in its reflection, and is slower in tracing any analogy, or investigating any truth. Man, thus organized, may pos­sess judgment, but not wit. The farther he is from this perfect degree of organic elasticity, the more his activity of mind is diminished; he may even be at such a distance from it, as to possess no powers of imagina­tion at all. In this state he can pronounce [Page 251]on the relations of those objects only which immediately act on the senses; and principles, to such a person, are without consequences. Hence the reason why sal­lies of wit, happy flights of any kind, never occur to us when the mind is fa­tigued.

But when this equilibrium between the fibres and nervous fluid, which forms Man's disposition to sagacity, is destroyed, and the scale inclines to the latter, vivacity of mind becomes volatility. The soul being then strongly affected by the most minute^* objects, re-acts^† on the body with a force proportionate thereto, communicates to this fluid a very strong impulse which, acting upon weak fibres, renders them rigid, and destroys sagacity, together with the free exercise of the un­derstanding.

To this sensibility add the delicacy, which is inseparable from it, and which ren­ders us incapable of sustaining for any long [Page 252]time that laborious attention, which is often necessary to the discovery of remote relations. Thus too hasty in pronouncing on the relations of things, the mind al­ways falls short of the end which it de­sires to attain, forms forced reasonings, and continues for ever ignorant.

The ideas, to be just, must be distinct, al­though these qualities are not inseparable. Thus in every case where justness of our ideas requires them to be numerous, the mind, if united to a body of very deli­cate texture and extreme sensibility, can scarce conceive any thing distinctly. In a man so circumstanced, the mind has not time to examine throughly any of the objects as they offer: they shift so fast, that he has hardly time to perceive them.

Hence the mind can have only imper­fect notions of things, and all its know­ledge is but a confused huddle of errors and absurdities.

Organization contributes to render MAN either prudent or inconsiderate.

The soul united to weak, elastic and delicate organs, being continually acted upon by strong sensations and sentiments, displays them the moment it is affected by them^*. Such a person therefore is inca­pable of dissimulation. Endued with too great sensibility to dissemble, he is like­wise too much so to reflect, to secure his purposes, to comply with, and bend to cir­cumstances, or patiently pursue a scheme, till he finds some clue, which may serve to guide him. Hence he is incapable of that circumspection, which conceals hidden resources, till it sees a fit occasion to make use of them; he knows not what to con­ceal, but tells the whole of what he knows, and thus betrays his own secrets. Impru­dent in discourse, he is so likewise in his designs and actions; his ardor ever carries him to lengths little suited to his strength, and by the improper use he makes of it, almost all his efforts prove ineffectual; in [Page 254]a word, he is neither fit for executing nor for counsel.

Prudence therefore depends on that state of the machine, on that tone of the fibres which promotes the free exercise of thinking, by moderating the vivacity of the sensitive fa­culty. Only the Man, whose organs are thus formed, can be severe, yet gentle, tender, though not weak, and high-spiri­ted without being a bravado; he alone can conceal his designs under the veil of silence, and be at once communicative and discreet. This calm, this exter­nal serenity proceeds therefore from a natural coolness of temper; and it is to the want of sensibility in our organs, that this boasted wisdom, this prudence we va­lue ourselves so much upon are owing.

Why MAN appears to lose some of his mental Faculties without losing the others.

Some men lose the power of meditat­ing, yet retain their other faculties. Some lose remembrance, imagination, the power of reflection, yet retain that of recollec­tion and judgment: some forget one kind [Page 255]of ideas, one sort of knowledge, without prejudice to others: in a word, some seem to lose every mental power, instinct ex­cepted.

The most celebrated philosophers, to ac­count for these phenomena, have imagin­ed a system, plausible at first sight, but in reality exceedingly absurd. They have first supposed, contrary to truth, that each faculty of the soul has some particular or­gan for its seat, entirely disjoined from, and without relation to the others. They have afterwards laid it down as a maxim, that, when one of these organs is vitiated, the faculty resident therein is depraved likewise. Finally, to make this system quadrate with facts, they have concluded, that in the general disarrangement of the machine, every part of which is intimate­ly connected, these different organs, seats of the different faculties^* are not all af­fected at the same time.

To elucidate these phenomena, I shall not undertake a mysterious explanation, [Page 256]which supposes us to be endowed with know­ledge which we have not; nor imitate the explanations of others, which are equally repugnant to reason and experience. All these phenomena, which appear so whim­sical, and so impossible to account for, ac­cording to the system of these philoso­phers, are so very simple, according to that which is here established, that the only thing to be wondered at is their simplicity. We have seen that reason, imagination, re­membrance, recollection, penetration, sa­gacity, &c. are powers of the mind, de­pendent on the different tones of the or­ganic elasticity of the fibres. It is there­fore evident, that these effects must dis­appear with their causes. I shall attempt farther to develope this principle, and give it the clearest evidence of truth.

These faculties of the soul, viz. sensi­bility, will, memory, and understanding, have different functions, as has been al­ready proved; but these faculties unite and combine in many different manners: from these their combinations result thought, and the different operations of the mind. But unless they act conjunct­ly, [Page 257]Man has neither sentiments nor ideas; their separation destroys every operation of the mind, and, in appearance, annihilates the faculties themselves.

Although these different faculties mutu­ally combine, they however combine not all in the same act: according as their combination varies, so much the more different are their results. Besides, though our intellectual faculties are the sole prin­ciples of the operations of the soul, and although some are active of themselves, their exercise is nevertheless entirely de­pendent on the body. The mind cannot proceed alone: it ever requires a certain degree of organic elasticity in the fibres, to think, reflect, meditate, &c. From these different degrees of the organic elas­ticity of the fibres, results every diversity in the operations of the mind.

Regular thought ever requires a tension of the fibres: but to think on some parti­cular subjects, there is required a much greater degree of organic elasticity in the fibres, than to think on some others; as on metaphysical subjects, than on those of elementary geometry; there is likewise [Page 258]required a much greater degree of organic elasticity to meditate than to reflect, to imagine something new, than to judge of simple facts. Thus with one degree of organic elasticity Man can reflect, with another meditate; so with one he can imagine, and with another weaker degree, which leaves him unable to recall the ideas and sensations formerly deposited in the memory, he can pronounce on his pre­sent sensations only, and seems to have lost every faculty but instinct: with a degree, yet weaker than this, he is unable to com­bine two single sensations, and is destitute of every sentiment, even that of his own existence.

Thus Man may lose the power of me­ditation, and retain that of reflection; he may lose imagination, sagacity, and pene­tration, and retain good sense; lastly, he may lose judgment, and yet retain instinct.

Both remembrance and recollection re­quire the organic elasticity of the fibres; but not in an equal degree. Recollection requires the greater degree of tension of the two, as any one may be convinced by the efforts which a mind, exhausted by [Page 259]study, or during the state of convales­cence or drowsiness, vainly makes to re­call the most familiar ideas, such as when called to mind by being mentioned by others, it remembers to have before receiv­ed. This is very natural; for it requires more attention to fix on an absent ob­ject, than on one which is present; to re­call an analogy without the aid of the sen­ses, as in remembrance by the assistance of objects, than to discover its identity: Man therefore may lose recollection and yet retain remembrance.

Finally, a greater degree of organic e­lasticity is required to recall extraordinary ideas, than to recollect those which are fa­miliar; and abstract ideas than simple: so likewise Man may forget one particular sort of ideas, and yet retain another. Thus the different degrees of organic elasticity of the fibres produce new combinations, which interrupt the succession of our thoughts, disorder the chain of our ideas, and seem even to annihilate some of ous mental faculties, while they leave us the free exercise of others. This is the sim­ple and manifest cause of these singular phenomena.

[Page 260]The different degrees of organic elas­ticity required in the different operations of the mind, may be determined by com­paring the course of the fluids, the num­ber of pulsations, their different degrees of force and vivacity, in one man during meditation, in another during reflection, and in another during revery; and by comparing the course of the fluids, the number of pulsations, their different de­grees of force and vivacity in the same man in all these different states.

Thus having shewn the principles of these phenomena in the different tones of the fibres, having discovered the truth of these laws in Nature, we may easily proceed to estimate their effects: notwith­standing this subject may be extremely complicated, and may appear to have but little connection with mathematics, it is possible to determine their relations, and to subject them to a precise evaluation; the balance has been already pointed out, it now remains only to take the amount.

From what has preceded, it is certain that the propensities, the affections and cha­racter of the soul, folly, wisdom, stupidity, [Page 261]prudence, reason, imagination, recollection, remembrance, penetration, delicacy, sublimity, depth, sagacity and genius, are not qualities inherent in the mind, but modes of the soul's existence, depending on the state of the organs of the body; as for instance, colours, sounds, heat, cold, &c. are not essential attributes of matter, but qualities dependent on its texture, and on the motion of its constitu­ent corpuscles. It is therefore evident, that organization alone causes almost^* every difference which is observed between souls; that they receive their principal cha­racteristics from the corporeal organs; and that, supposing them really in their na­ture different from each other, this dif­ference would be of no effect, so long as they continue united to the body.

Thus every thing in Nature is influenced by physical laws.

Corporeal sensibility, the regular or disor­dered course of our fluids, primitive or or­ganic [Page 262]elasticity, the rigidity or relaxation of the fibres, the force or volume of the organs, are the causes of the surprising diversities in souls, and the secret principles of that great influ­ence of the soul on the body, and of the body on the soul, hitherto deemed an impenetrable mystery.

Such are the secret causes of that sin­gular harmony, which philosophers have observed between the two substances which form our being, but were unable to explain.

Such, in a word, are the true founda­tions, the solid basis of a science, where­in every thing appeared arbitrary, obscure and mysterious.

I would here conclude my work, were philosophers only to be my readers: to such it might be sufficient to explain the principles on which I ground my doctrine, and I might have spared myself the trou­ble of entering into these particulars which are necessary to elucidate them. But this were lost labour: since, for one reader who can develop the whole of a system by the mere outlines, there are a thou­sand who must see the whole chain of rea­soning, [Page 263]in order to comprehend the prin­ciples on which it is established.

To these it is necessary to enter into a minute discussion: it is not enough that they have given them a clue to guide them to the truth, and have the path pointed out to them; they must be, as it were, led by the hand through all the mazes of the labyrinth; otherwise they must una­voidably be bewildered in it.