Revival: Psychology: Normal and Morbid (1901)

Charles Arthur Mercier

• Publisher: Routledge
• Year: 2018
• Print ISBN: 9781138553842
• eBook ISBN: 9781351346139
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

Insanity is no exception to the rule which requires a knowledge of the normal as an indispensable preliminary to a knowledge of the abnormal. This book, published in 1901, aimed to provide the first systematic examination of the disorders of the mind as arranged and correlated with the normal types from which they arringly depart.

Thought

The second of the primitive divisions or faculties of mind consists of those states of consciousness that correspond neither with the reception of motion into nor with the emission of motion from the highest nerve regions, but with the rearrangement or redistribution of motion in them; that is to say, with the decompositioh and combination that the motion undergoes. It is by this rearrangement of motion that the acts, operated by the motion emitted, are adapted to the circumstances which impress motion upon the organism. An approaching cart impresses, on the eye and ear, motion which is carried to the supreme nerve tract. From this tract are emitted currents of motion, so directed and combined, that the body is removed out of the way of the cart. Between the reception of motion by the supreme nerve tract and the emission of motion from it, is interposed a process by which the outgoing currents are combined and directed in such a way that the resulting act is adapted to the circumstances from which the motion arises. The individual impressed does not lie down in the road, nor stand still, nor mark time, nor walk up against the cart. He gets out of the way. The process of regulating conduct to circumstances is called Intelligence, and when it occurs in the highest nerve regions, it has, like other material processes in those regions, a conscious accompaniment, which, in this instance, is called Thought or Thinking.

That Intelligence is the outcome of the rearrangement or redistribution, that is to say, of the composition and resolution of motion, is pretty evident. In the great majority of adapted acts, the amount of motion is far greater than the amount received. When an approaching cart comes into view, the amount of motion that impinges on the retina is so infinitesimally small that, if it could be accurately measured, it would require a prodigious number of decimal figures to express it in foot-pounds. In order to produce the movement of the body out of the way of the cart, much motion must be added to and combined with that received; and although all of this motion is not added in the nervous system, yet some of it is undoubtedly added there. What is true of this case is true of every case in which adapted movements follow impressions. When a cricketer strives to catch a ball, some of the motion which is reflected from the ball on to the retina is distributed in the nervous system so as to arouse movements of the legs, some of it is so distributed as to arouse movements of the head and eyes, some to arouse movements of the arms and hands. The incident motion is, in the nervous system, resolved, or redistributed, and, without such resolution or redistribution of incident motion, adaptation of conduct to circumstances is impossible.

Further consideration reveals the fact that while the redistribution of motion is necessary to the adaptation of conduct to circumstances, it is also the sole factor that is necessarily involved in this adaptation. Given the power of receiving and of emitting motion, then the power of adapting the mode of emission to the circumstances which impress the motion can be only the redistribution of motion; that is to say, its combination with other motion simultaneously arriving or already resident in the organism, and its resolution into several streams, or currents, or modes of motion.

When we seek the factors which condition this redistribution of motion, it is obvious that they can be found only in the physical constitution or molecular arrangement of the medium in which the motion takes place. When a ray of light passes through a crystal of Iceland spar, it is split into two rays, which follow divergent paths. This resolution of motion is conditioned by the physical constitution of the spar. In passing through other translucent media the ray remains undivided, or, if divided, its resolvents pursue paths different from those that they follow through the spar. When a ray of light impinges upon a metallic surface, it is partly reflected, partly absorbed, and partly diffracted ; and the resolution which the ray thus undergoes is conditioned absolutely by the state of the surface of the metal ; that is to say, by its physical constitution. So when a wave of motion passes through any portion of the nervous system, the direction which the motion will take, its composition or its resolution, depends entirely upon the physical constitution of the portion of the nervous system through which it passes.

Now the physical constitution of the nervous system exhibits, with respect to the manner in which it affects traversing fasciculi of motion, a twofold structure. In parts the arrangement of the elements of the grey matter is so fixed, so definitely and completely organised, that motion incident upon these parts pursues a course as definite and as invariable as that of a ray of light through a crystal of Iceland spar. Once arrived within the confines of this organised territory, the path of the motion, its composition or resolution, is determined, fixed, invariable, and predictable, and suffers no interference from errant waves of motion. Just so the shape of the iron bar that issues from a rolling machine is seen to result inevitably from the conditions to which it has been subject.

In a different region of the nervous system—in that region which on several accounts is called the highest—the constitution of the tissue is widely different. Here the disposition of the routes in which entering waves of motion are directed is not so severely restricted. Instead of travelling in predetermined paths, which permit of no diversion or interference with its direction, a wave of motion is free to become diffused, and is subject to the influence of other diffused waves traversing the tissue in directions so various and in amounts so diverse that the course of any one may appear wholly capricious and undetermined. Just so the shape and movement of a wreath of smoke appear to be capricious and indeterminate, although they are actually conditioned by rigid laws.

In both parts of the nervous system the path and distribution of the motion is conditioned by the molecular structure ; but in one part this structure is fixed, rigid, consolidated, and the path and distribution of the motion invariable, while in the other the molecular structure is plastic, it is embryonic, it is unformed, but in course of formation under the influence of incident motion; it is so little determinate and so much liable to modification that two successive waves of entering motion, similar in amount and similar in direction, may issue in very different directions and combinations, find so give rise to very different sets of movements, to very different forms of conduct.

Between these two forms, or rather stages, of organisation there lie stages of every intermediate degree, from those which are just beginning to be organised, and to admit of the easier passage of motion in some directions than in others, to those whose organisation is almost complete, and admits of the modification of their action only to a slight extent and by powerful influences.

At the one end of the scale is the structure by which the heart's action is produced, structure so completely organised that, so long as its constitution remains intact, it admits of variation neither in the direction nor in the composition nor resolution of the motion which it distributes, the only variation possible being in the rate of action, which is manifestly dependent on the rate of arrival of motion. Approximating to this structure are those which actuate the movements of the pupils, of the blood vessels, and other hollow viscera ; of breathing, of coughing, of blinking, and all those that are commonly included under the title of reflex acts. Less completely organised, and therefore more liable to modification by external influences, are the nervous structures which actuate the automatic movements, as of locomotion, of articulation, of ingrained handicrafts, and so forth. Less determinate still are the structures through which are actuated the habitual and less oft-repeated acts ; while for wholly novel acts there is no readymade mechanism provided. They are actuated by motion which issues from the highest nerve regions in combinations determined from moment to moment by the force and direction of the waves of motion which happen to be prevalent there at the time.

It appears, therefore, that while all acts are dependent on the molecular constitution of the nervous system from which the actuating motion issues, some acts are completely determinate, owing to the fixed and determinate structure of the actuating tissue; while others are more or less indeterminate owing to the more or less plastic and indeterminate structure on whose activity they depend. It will be convenient if we designate determinate structure by the term mechanism.

It will be seen that a very large number of adaptations of acts to circumstances—that is, of intelligent acts—depend more or less upon mechanism as thus defined. The sudden closure of the eye in adaptation to the approach of a foreign body, the movements of equilibration in adaptation to the force of gravity, are actuated by fully formed mechanisms. The movements of articulation, of acquired handicrafts, and a thousand other movements, are actuated by partly formed mechanisms. Each such mechanism is a potential adaptation of acts to circumstances. It is by the activity of the mechanism that the adaptation is made. Before the mechanism is formed, the adaptation is extremely imperfect, as we see in the efforts of children learning to walk, to talk, to read, etc. But when the adaptation is not required, when there is no need for winking, for walking, for speaking, for writing, no adaptation is made ; the mechanism remains inactive. Such mechanisms are, of course, structural memories, but it is obvious that they may be regarded also as structural intelligence. They are adaptations in posse of acts to circumstances, though they may not be adaptations in esse. When they become functionally active; when they are the seat of activity; when motion passes through them—then they are adaptations in esse : then they give rise to acts, and the act, which is operated by the motion that they emit, is adapted to the circumstances which impressed upon the organism the motion that they receive. The functional activity of such a mechanism may be regarded as active intelligence.

The nervous mechanisms which effect the movements of the viscera are for the most part fully formed, while of those that actuate conduct but few are so complete as not to admit of modification in conformity with variations in the circumstances to be dealt with. Where there is no variation in the circumstances, and where these circumstances have been sufficiently often repeated in the life of the race, the mechanism has become completed, and the action follows as unfailingly and as unvaryingly upon receipt of the impression as the discharge of the loaded gun follows upon the pulling of the trigger. With such inevitable unvaryingness the eyelids close on the rapid and near approach of an object. With such inevitable unvaryingness the arms are thrust out when the body is falling forwards. With such inevitable unvaryingness follows the jerk of withdrawal upon a sudden painful impression.

But the great bulk of the circumstances which impress motion upon the organism are variable within narrower or wider limits, and consequently the great bulk of the mechanisms which have grown up in dealing with these circumstances retain more or less of their original plasticity. In some respects fully organised, so that in those respects the activity that they produce is unvarying, in other respects they remain plastic, so that in these respects the activity resulting from their action is capable of modification to meet the varying impressions made by the circumstances.

Of such mechanisms the nervous system of each animal contains a number proportioned to the variety of circumstances to which it has habitually to adapt itself, and of these mechanisms some exist fully formed at birth, while others are only partially organised at that time, and others again are wholly formed in the lifetime of the individual. The mechanism for walking is fully formed in the chick at birth, as are the mechanisms for crying and sucking in the human infant. But the mechanisms for walking, articulation, and handicrafts are, in the human organism, formed after birth, and never attain to the completeness of organisation of the congenital mechanisms.

The great majority of the structural mechanisms which actuate conduct are formed during the life of the individual, and in every individual there are, especially in early life, many mechanisms in course of formation. The question at once arises, How are these mechanisms formed ? And obscure as the process is, and defective as is our knowledge, both of the structure and of the recondite processes of the nervous system, the question admits of an answer which, if not complete, may be taken as correct as far as it goes. Briefly, the mechanisms are structural memories, and their formation is subject to the same laws that determine the formation of other memories. When a ray of light passes through a crystal of Iceland spar it passes, as is supposed, between the molecules of the spar, and without disturbing them from their position. The motion is the motion of the ether, which occupies the interstices of the molecules, and not that of the molecules themselves. It is otherwise with the passage of motion through the nervous system. The motion is motion, not of the ether, but of the molecules themselves, and is communicated from molecule to molecule. When motion passes through the nervous system the molecules are disturbed. If stationary, they are moved into new positions; if, as is more probable, they are already in motion, their motion undergoes perturbation. Now (see Memory) when motion is incident upon an organic body so as to distort it beyond the limits of its elasticity, the distortion remains after the motion ceases. In the case of the embryonic or unmechanised nerve tissue it appears that the effect of this distortion is such as to facilitate the subsequent passage of motion in the same path. If a wave of motion has once pursued a certain course, then subsequent motion incident upon the same spot will tend to follow the same course. If a wave of motion has at any point in its course been deflected or split up, or combined with another wave, or meets and discharges a magazine of motion, then at that same point a subsequent wave will tend to undergo a similar modification. And every successive wave of motion that pursues that path and undergoes successive modifications in its course will facilitate the passage of subsequent waves along the same path, will increase their tendency to receive similar modifications at the same points. At the same time, there will occur, or rather, as a part of the same change there must occur, an increasing immunity of the same wave of motion from disturbance by increments of motion that are extraneous to the mechanism in course of formation. It is evident that if the wave of motion tends more and more to pursue a given course and to undergo given modifications, it tends less and less to be disturbed from that course and to undergo modifications that are incompatible with the given modifications. So that by the repeated passage of motion along a given course, the structure of that part of the nervous system through which it passes becomes so modified that the course becomes more and more determinate, less and less subject to modification. But a structure such that motion in passing through it pursues a determinate course is a mechanism. So that nervous mechanisms are formed, we find, by the repeated passage of motion along a certain course. In other words, when an adjustment to circumstances has once been effected, its repetition is more easily effected than its original formation ; and with every subsequent repetition facility is increased until a maximum is reached which indicates the formation of a mechanism for its accomplishment. The mechanism once completed, no further increase in the facility of the adjustment can occur. Thus we find that when an adjustment is frequently repeated, a certain degree of facility is rapidly attained, but that the facility does not increase indefinitely. The rate of increase soon slackens, and at length a standard is reached, beyond which no increase takes place. This series of events is familiar to everyone. Everyone attains to a certain facility of equilibration, although very few attain to that perfection which is evidenced in gracefulness of gait; and beyond that degree of facility peculiar to himself, no amount of practice in walking will take him. Everyone attains to a certain fluency and distinction of articulation, which is great in some and less in others ; but for each one there is a standard, beyond which no amount of practice will carry him. So that the old saying, “ Practice makes perfect/ expresses, as do most current sayings, an approximation to the truth, but not the exact truth. Practice does of necessity bring improvement, and sufficient practice will ensure improvement up to the maximum capacity of the practiser, but it will not ensure perfection except in the exceptionally endowed.

Once an adjustment of conduct to circumstances has been made, the organisation of a nervous mechanism by which the repetition of that adjustment is facilitated is a simple affair. What still remains to be explained is the original formation of an entirely new adjustment to circumstances, a process to which the term Intelligence will be allowed less grudgingly than to the structural mechanisms to which we have hitherto applied it—the process whose mental accompaniment is the process of Thinking. When a new adjustment to circumstances is made, what is the process that takes place in the nervous system ? Let us take a concrete instance. When a sheet of postage stamps is bought, the stamps cannot be used until they have been separated from each other. Hitherto they have always been separated either by cutting them with scissors or by folding them, and tearing, or cutting them with a knife, down the fold. But these methods are defective, since scissors or knives are not always at hand, and the tear is apt to run irregularly and to tear the stamps in two. At length a man hits upon the expedient of dividing the stamps by lines of perforations, in which lines a tear will be directed and limited, without the aid either of cutting instruments or of a preliminary folding of the sheet. How, we have to ask, is this new adjustment to circumstances arrived at? and what is the nervous process by which it is actuated ? The circumstances—the sheet of stamps, and the continuity of each stamp with its neighbours, the letters each awaiting a single stamp—impress upon tfye organism motion, which pursues its customary paths and rouses whatever activities are potential in the structure that it passes through.

The course that the stream of moti...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication Page
• Table of Contents
• Introduction
• Sensation
• Thought
• Volition
• Memory
• Pleasure and Pain
• Subject-Consciousness
• Index