Observations on Man (6th edition)/Part I/Chapter III/Section VI

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Observations on Man (6th edition) by David Hartley
Chapter III, Section VI

Section VI[edit]


Prop. XCII.—To examine how far Deviations from sound Reason, and Alienations of Mind, are agreeable to the foregoing Theory.

Mad persons differ from others, in that they judge wrong of past or future facts of a common nature; that their affections and actions are violent and different from, or even opposite to, those of others upon the like occasions, and such as are contrary to their true happiness; that their memory is fallacious, and their discourse incoherent; and that they lose, in great measure, that consciousness which accompanies our thoughts and actions, and by which we connect ourselves with ourselves from time to time. These circumstances are variously combined in the various kinds and degrees of madness; and some of them take place in persons of sound minds, in certain degrees, and for certain spaces of time: so that here, as in other cases, it is impossible to fix precise limits, and to determine where soundness of mind ends, and madness begins. I will make some short remarks, deduced from the theory of these papers upon the following states of mind, which all bear some relation to one another, and all differ from the perfection of reasoning natural to adults, according to the ordinary course of things, viz.

  1. The erroneousness of the judgment in children and idiots.
  2. The dotage of old persons.
  3. Drunkenness.
  4. The deliriums attending acute or other distempers.
  5. The frequent recurrency of the same ideas in a course of study or otherwise.
  6. Violent passions.
  7. Melancholy.
  8. Madness.
The Erroneousness of the Judgment in Children and Idiots.

Children often misrepresent past and future facts; their memory is fallacious; their discourse incoherent; their affections and actions disproportionate to the value of the things desired and pursued; and the connecting consciousness is in them as yet imperfect. But all this follows naturally from the observations made above concerning the methods in which we learn to remember and relate past facts, to judge of future ones, to reason, and to express ourselves suitably to each occasion; also in which our hopes and fears are made to depend upon symbols. No particular account is therefore required for these phænomena; they are strictly natural; and many of the chief reasons for the imperfection of the memory and judgment in children occurring perpetually, and being very obvious, it is not usually supposed, that any particular account is required. However, if an adult should become subject to a like erroneousness, it would evidently be one species of madness; as fatuity or idiotism is. Here the brain labours under such an original disorder, as either not to receive a disposition to the miniature vibrations in which ideas consist, and whence voluntary motions are derived, but with great difficulty; or if it receive such dispositions readily, they have not the usual permanency; in both which cases it is evident, that the memory, with all the faculties thereon depending, must continue in an imperfect state, such as is observed in idiots. The want of the connecting consciousness in children and idiots, and indeed in maniacs of various kinds, excites our pity in a peculiar manner, this connecting consciousness being esteemed a principal source and requisite of happiness. Their helplessness, and the dangers to which they are exposed without foreseeing them, contribute also to enhance our compassion.

Of Dotage.

The dotage of old persons is oftentimes something more than a mere decay of memory. For they mistake things present for others, and their discourse is often foreign to the objects that are presented to them. However, the imperfection of their memory in respect of impressions but just made, or at short intervals of past time, is one principal source of their mistakes. One may suppose here that the parts of the brain in which the miniature vibrations belonging to ideas have taken place, are decayed in a peculiar manner, perhaps from too great use, while the parts appropriated to the natural, vital, and animal motions remain tolerably perfect. The sinuses of the brain are probably considerably distended in these cases, and the brain itself in a languishing state; for there seems to be a considerable resemblance between the inconsistencies of some kinds of dotage, and those of dreams. Besides which it may be observed, that in dotage the person is often sluggish and lethargic; and that as a defect of the nutritive faculty in the brain will permit the sinuses to be more easily distended, so a distention of the sinuses, from this or any other cause, may impede the due nutrition of the brain. We see that, in old persons, all the parts, even the bones themselves, waste and grow less. Why may not this happen to the brain, the origin of all, and arise from an obstruction of the infinitesimal vessels of the nervous system, this obstruction causing such a degree of opacity, as greatly to abate, or even to destroy, the powers of association and memory? At the same time vibrations, foreign to the present objects, may be excited from causes residing in the brain, stomach, &c. just as in sleep.

Of Drunkenness.

The common and immediate effect of wine is to dispose to joy, i.e. to introduce such kinds and degrees of vibrations into the whole nervous system, or into the separate parts thereof, as are attended with a moderate continued pleasure. This it seems to do chiefly by impressing agreeable sensations upon the stomach and bowels, which are thence propagated into the brain, continue there, and also call up the several associated pleasures that have been formed from pleasant impressions made upon the alimentary duct, or even upon any of the external senses. But wine has also probably a considerable effect of the same kind, after it is absorbed by the veins and lacteals, viz. by the impressions which it makes on the solids, considered as productions of the nerves, while it circulates with the fluids in an unassimilated state, in the same manner, as has been already observed of opium; which resembles wine in this respect also, that it produces one species of temporary madness. And we may suppose, that analogous observations hold with regard to all the medicinal and poisonous bodies, which are found to produce considerable disorders in the mind; their greatest and most immediate effect arises from the impressions made on the stomach, and the disorderly vibrations propagated thence into the brain; and yet it seems probable, that such particles as are absorbed, produce a similar effect in circulating with the blood.

Wine, after it is absorbed, must rarefy the blood, and consequently distend the veins and sinuses, so as to make them compress the medullary substance, and the nerves themselves, both in their origin and progress; it must therefore dispose to some degree of a palsy of the sensations and motions; to which there will be a farther disposition from the great exhaustion of the nervous capillaments, and medullary substance, which a continued state of gaiety and mirth, with the various expressions of it, has occasioned.

It is moreover to be noted, that the pleasant vibrations producing this gaiety by rising higher and higher perpetually, as more wine is taken into the stomach and blood-vessels, come at last to border upon, and even to pass into, the disagreeable vibrations belonging to the passions of anger, jealousy, envy, &c. more especially if any of the mental causes of these be presented at the same time.

Now it seems, that, from a comparison of these and such like things with each other, and with what is delivered in other parts of these papers, the peculiar temporary madness of drunken persons might receive a general explanation. Particularly it seems natural to expect that they should at first be much disposed to mirth and laughter, with a mixture of small inconsistencies and absurdities; that these last should increase from the vivid trains which force themselves upon the brain, in opposition to the present reality; that they should lose the command and stability of the voluntary motions from the prevalence of confused vibrations in the brain, so that those appropriated to voluntary motion cannot descend regularly as usual; but that they should stagger, and see double: that quarrels and contentions should arise after some time; and all end at last in a temporary apoplexy. And it is very observable, that the free use of fermented liquors disposes to passionateness, to distempers of the head, to melancholy, and to downright madness; all which things have also great connexions with each other.

The sickness and head-ache which drunkenness occasions the succeeding morning, seem to arise, the first from the immediate impressions made on the nerves of the stomach; the second from the peculiar sympathy which the parts of the head, external as well as internal, have with the brain, the part principally affected in drunkenness, by deriving their nerves immediately from it.

Of Deliriums.

I come next to consider the deliriums which sometimes attend distempers, especially acute ones. In these a disagreeable state is introduced into the nervous system by the bodily disorder, which checks the rise of pleasant associations, and gives force and quickness to disgustful ones; and which consequently would of itself alone, if sufficient in degree, vitiate and distort all the reasonings of the sick person. But besides this, it seems, that, in the deliriums attending distempers, a vivid train of visible images forces itself upon the patient’s eye, and that either from a disorder in the nerves and blood-vessels of the eye itself, or from one in the brain, or one in the alimentary duct, or which is most probable, from a concurrence of all these. It seems also that the wild discourse of delirious persons is accommodated to this train in some imperfect manner; and that it becomes so wild, partly from the incoherence of the parts of this train, partly from its not expressing even this incoherent train adequately, but deviating into such phrases as the vibrations excited by the distemper in the parts of the brain corresponding to the auditory nerves, or in parts still more internal, and consequently the seats of ideas purely intellectual, produce by their associated influence over the organs of speech.

That delirious persons have such trains forced upon the eye from internal causes, appears probable from hence, that when they first begin to be delirious, and talk wildly, it is generally at such times only as they are in the dark, so as to have all visible objects excluded; for, upon bringing a candle to them, and presenting common objects, they recover themselves, and talk rationally, till the candle be removed again. For hence we may conclude, that the real objects overpower the visible train from internal causes, while the delirium is in its infancy; and that the patient relapses, as soon as he is shut up in the dark, because the visible train from internal causes overpowers that which would rise up, was the person’s nervous system in a natural state, according to the usual course of association, and the recurrent recollection of the place and circumstances in which he is situated. By degrees the visible train, from internal causes, grows so vivid, by the increase of the distemper, as even to overpower the impressions from real objects, at least frequently, and in a great degree, and so as to intermix itself with them, and to make an inconsistency in the words and actions; and thus the patient becomes quite delirious.

Persons inclining to be delirious in distempers are most apt to be so in going to sleep, and in waking from sleep; in which circumstances the visible trains are more vivid, than when we are quite awake, as has been observed above.

It casts also some light upon this subject, that tea and coffee will sometimes occasion such trains; and that they arise in our first attempts to sleep after these liquors.

As death approaches, the deliriums attending distempers abound with far more incoherencies and inconsistencies, than any other species of alienations of the mind; which may easily be conceived to be the natural result of the entire confusion and disorder which then take place in the nervous system. However, there are some cases of death, where the nervous system continues free from this confusion to the last, as far as the by-standers can judge.

The Frequent Recurrency of the same Ideas.

When a person applies himself to any particular study, so as to fix his attention deeply on the ideas and terms belonging to it, and to be very little conversant in those of other branches of knowledge, it is commonly observed, that he becomes narrow-minded, strongly persuaded of the truth and value of many things in his own particular study, which others think doubtful or false, or of little importance, and after some time subject to low spirits, and the hypochondriacal distemper. Now all this follows from observations already made. The perpetual recurrency of particular ideas and terms makes the vibrations belonging thereto become more than ordinarily vivid, converts feeble associations into strong ones, and enhances the secondary ideas of dignity and esteem, which adhere to them, at the same time that all these things are diminished in respect of other ideas and terms that are kept out of view; and which, if they were to recur in due proportion, would oppose and correct many associations in the particular study, which are made not according to the reality of things, and keep down our exorbitant opinions of its importance. The same perpetual recurrency of vibrations, affecting one and the same part of the brain, in nearly one and the same manner, must irritate it at last, so as to enter the limits of pain, and approach to the states peculiar to fear, anxiety, despondency, peevishness, jealousy, and the rest of the tribe of hypochondriacal passions.

Sleep, which presents ideas at hazard, as one may say, and with little regard to prior associations, seems to be of the greatest use in keeping off the hypochondriacal distemper in such persons: however, without a change of studies, this, with great narrow-mindedness, will probably come at last.

It follows from the same method of reasoning, that since the concerns of religion are infinite, so that we can never over-rate them, we ought to make the ideas, motives, and affections, of this kind, recur as often as possible. And if this be done in a truly catholic spirit, with all that variety of actions which our duty to God, our neighbour, and ourselves, requires, there will be no danger of introducing either narrow-mindedness or hypochondriacism. And it ought to be esteemed the same kind and degree of alienation of mind to undervalue a thing of great importance, as to over-value one of small.

Of Violent Passions.

Persons that are under the influence of strong passions, such as anger, fear, ambition, disappointment, have the vibrations attending the principal ideas so much increased, that these ideas cling together, i.e. are associated in an unnatural manner; at the same time that the eagerness and violence of the passion prevent the formation of such associations, or obscure them, if already formed, as are requisite for the right apprehension of the past and future facts, which are the objects of this passion. Violent passions must therefore disorder the understanding and judgment, while they last; and if the same passion return frequently, it may have so great an effect upon the associations, as that the intervention of foreign ideas shall not be able to set things to rights, and break the unnatural bond. The same increase of vibrations makes all the principal ideas appear to affect self, with the peculiar interesting concerns supposed to flow from personal identity; so that these vibrations exert a reflected influence upon themselves by these means. And thus it appears, that all violent passions must be temporary madnesses, and all habits of them permanent ones, agreeably to the judgment of the wise and good in these things. It appears also, that violent fits of passion, and frequent recurrences of them, must, from the nature of the body, often transport persons, so that they shall not be able to recover themselves, but fall within the limits of the distemper called madness emphatically.

Of Melancholy.

The next species of alienations of the mind is melancholy. Vapours, hypochondriacal, and hysterical disorders, are comprehended under this class. The causes of it are self-indulgence in eating and drinking, and particularly in fermented liquors, want of due bodily labour, injuries done to the brain by fevers, concussions, &c., too much application of the mind, especially to the same objects and ideas, violent and long-continued passions, profuse evacuations, and an hereditary disposition; which last we may suppose to consist chiefly in an undue make of the brain.

In women the uneasy states of the uterus are propagated to the brain, both immediately and mediately, i.e. by first affecting the stomach, and thence the brain. In men the original disorder often begins, and continues for a long time, chiefly in the organs of digestion.

The causa proxima of melancholy is an irritability of the medullary substance of the brain, disposing it upon slight occasions to such vibrations as enter the limits of pain; and particularly to such kinds and degrees, as belong to the uneasy passions of fear, sorrow, anger, jealousy, &c. And as these vibrations, when the passions are not in great excess, do not much transgress the limits of pleasure, it will often happen that hypochondriac and hysteric persons shall be apt to be transported with joy from trifling causes, and be, at times, disposed to mirth and laughter. They are also very fickle and changeable, as having their desires, hopes, and fears, increased far beyond their natural magnitude, when they happen to fall in with such a state of brain as favours them.

It often happens to these persons to have very absurd desires, hopes, and fears; and yet, at the same time, to know them to be absurd; and, in consequence thereof, to resist them. While they do this, we may reckon the distemper within the bounds of melancholy; but when they endeavour to gratify very absurd desires, or are permanently persuaded of the reality of very groundless hopes and fears, and especially if they lose the connecting consciousness in any great degree, and violate the rules of decency and virtue (the associations of this kind being overpowered, as it were, in the same manner as they are sometimes in dreams), we may reckon the distemper to have passed into madness, strictly so called; of which I now come to speak in a general brief way.

Of Madness.

The causes of madness are of two kinds, bodily and mental. That which arises from bodily causes is nearly related to drunkenness, and to the deliriums attending distempers. That from mental causes is of the same kind with temporary alienations of the mind during violent passions, and with the prejudices and opinionativeness, which much application to one set of ideas only occasions.

We may thus distinguish the causes for the more easy conception and analysis of the subject; but, in fact, they are both united for the most part. The bodily cause lays hold of that passion or affection, which is most disproportionate; and the mental cause, when that is primary, generally waits till some bodily distemper gives it full scope to exert itself. Agreeably to this, the prevention and cure of all kinds of madness require an attention both to the body and mind; which coincides in a particular manner with the general doctrine of these papers.

It is observed, that mad persons often speak rationally and consistently upon the subjects that occur, provided that single one which most affects them, be kept out of view. And the reason of this may be, that whether they first became mad, because a particular, original, mental uneasiness falls in with an accidental bodily disorder; or because an original, bodily disorder falls in with an accidental mental one; it must follow, that a particular set of ideas shall be extremely magnified, and, consequently, an unnatural association of sameness or repugnancy between them generated, all other ideas and associations remaining nearly the same. Thus, suppose a person, whose nervous system is disordered, to turn his thoughts accidentally to some barely possible good or evil. If the nervous disorder falls in with this, it increases the vibrations belonging to its ideas so much, as to give it a reality, a connexion with self. For we distinguish the recollection and anticipation of things relating to ourselves, from those of things relating to other persons, chiefly by the difference of strength in the vibrations, and in their coalescences with each other. When one false position of this kind is admitted, it begets more of course; the same bodily and mental causes also continuing; but then this process stops after a certain number of false positions are adopted from their mutual inconsistency (unless the whole nervous system be deranged); and it is often confined to a certain kind, as the irascible, the terrifying, &c.

The memory is often much impaired in madness, which is both a sign of the greatness of the bodily disorder, and a hindrance to mental rectification; and therefore a bad prognostic. If an opposite state of body and mind can be introduced early, before the unnatural associations are too much cemented, the madness is cured; if otherwise, it will remain, though both the bodily and mental cause should be at last removed.

Inquiries after the philosopher’s stone, the longitude, &c. to which men are prompted by strong, ambitious, or covetous desires, are often both cause and effect, in respect of madness. Excessive fits of anger and fear are also found often to hurry persons into madness.

In dissections after madness the brain is often found dry, and the blood-vessels much distended; which are arguments, that violent vibrations took place in the internal parts of the brain, the peculiar residence of ideas and passions; and that it was much compressed, so as to obstruct the natural course of association.

As in mad persons the vibrations in the internal parts of the brain are preternaturally increased, so they are defective in the external organs, in the glands, &c. Hence maniacs eat little, are costive, make little water, and take scarce any notice of external impressions. The violence of the ideas and passions may give them great muscular strength upon particular occasions, when the violent vibrations descend from the internal parts of the brain into the muscles, according to former associations of these with the voluntary motions (the same increase of vibrations in the internal parts of the brain, which hinders the ascending vibrations of sensation, augmenting the descending ones of motion). But maniacs are often very sluggish, as well as insensible, from the great prevalence of the ideal vibrations; just as persons in a state of deep attention are. An accurate history of the several kinds of madness from those physicians, who are much conversant with this distemper, is greatly wanted, and it would probably receive considerable light from this theory.

Religious considerations are the best preservative in hereditary or other tendencies to madness; as being the only sure means of restraining violent passions, at the same time that they afford a constant indefinite hope, mixed with a filial awe and fear; which things are eminently qualified to keep up a steadiness and sobriety of mind, and to incite us to such a course of action, as adds incessantly to the hope, and diminishes the fear. However, bodily labour, with a variety of mental occupations, and a considerable abstemiousness in the quantity and quality of diet, ought always to be joined.