The physiology of mind : being the first part of a third edition, revised enlarged and in great part rewritten, of "The physiology and pathology of mind"

Front matter

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Preface

The first edition of my work on the Physiology and Pathology of Mind was published in the year 1867. A second edition appeared in the following year, which was in due time exhausted, and the book has been out of print for some years. The delay in the publication of a third edition has been owing mainly to the occupations of active professional life, which have hindered the bestowal of the systematic work of revision and enlargement made necessary by the progress of physiological and psychological knowledge ; but partly also to a lack of enthusiasm in the labour, arising from a conviction that what was of value in the book had either been said already, or would anyhow very soon be said, by some one else. The current of psychological thought having set so strongly in physiological channels, it is pretty certain that the reflections which one person has had, however original they may seem to him, some other person has had, has now, or will very soon have. One is happily, too, more critical, as well as less enthusiastic

PREFACE.

and confident, at forty than at thirty years of age ; and a result of the more sober mood is that what seemed very important, and much needing to be said, at the earlier date, does not seem of so much consequence, or anywise to press for delivery, at the later date.

There was another inhibitory reflection, occasioned by a contemplation of the revolution in psychological method, which has been going on for some time now, and of the entirely different aspects which many psychological questions have assumed in consequence. The changes that have taken place have been so great and so rapid that a book written ten years ago must necessarily, unless re -written, be much out of date now.

In the preface to the first edition, the aim of the work was declared to be twofold : " first, to treat of mental phenomena from a physiological rather than from a metaphysical point of view ; and, secondly, to bring the manifold instructive instances presented by the unsound mind to bear upon the interpretation of the obscure problems of mental science — to do what I could to put a happy end to the 'inauspicious divorce' between the Physiology and Pathology of Mind." The way in which the fulfilment of the first part of this twofold aim was prosecuted did not fail to provoke much criticism, of the direct and indirect sort, from those who assumed that it was a reck-

PREFACE. vfi less attempt to discard entirely the psychological method of inquiry into mental phenomena, and to employ the physiological method exclusively. No doubt the energetic exposition of the shortcomings of the psychological method and the earnest advocacy of the physiological method lent some countenance to that supposition, but it was none the less directly contrary to the distinct enunciation of that which was advocated in the first chapter as the proper method of the study of mind, and with the method actually pursued in the execution of the work throughout. It was not possible to set forth adequately the fruitfulness and the rich promise of the physiological method, and to elevate it to its rightful position, without exposing the shortcomings of the psychological method, and degrading it to a lower rank than that which it had usurped.

The physiological method has made such great way that it stands not now in need either of defence or advocacy ; and the result cannot fail to be, as regards this book, that the exposition of its merits, made with all the vehemence of youthful enthusiasm, must look like a superfluous assertion of claims which are not seriously contested, while the record of acquisitions which have become part of the general body of thought certainly requires not the aggressive prominence which it had.

To adapt this edition in some measure to these

PREFACE.

new conditions, I have, while incorporating the entire substance of previous editions, omitted or modified various expressions and passages which seemed objectionable as they stood, and have sought to maintain the level of a more sober style ; and, in order to bring it even with the present state of knowledge, the original matter has been carefully revised and largely added to. The consequence has been that what was the First Part of former editions, treating of the Physiology of Mind, and had been written in the first instance in order to lay a foundation for the Second Part, which dealt with the Pathology of Mind, has grown so much, and attained by its growth such an independent character, as to render it advisable to make it a separate volume.

This volume is, then, presented as a treatise on the physiology of mind, and may stand on its own account as such, quite apart from the second volume which, following in due season, will be occupied entirely with the pathology of mind, and with the accomplishment of the second part of the twofold aim. Or, if it be thought too ambitious a thing to call it a treatise, let it be looked upon as a disquisition, by the light of existing knowledge, concerning the nervous structures and functions which are the probable physical foundations, or the objective aspects, of those natural phenomena which appear in consciousness as feelings and

PREFACE.

thoughts, and are known only in that way — that is to say, subjectively. Should any one choose to declare that the book is neither Physiology nor Psychology, but an ill-conceived medley, and be offended at what is offered to him, I am not careful to answer in that matter ; I am more wishful, in my unwisdom, that it should be in conformity with nature than with the divisions of sciences which he and those who think with him labour to impose upon nature by way of amendment upon its continuity and unity. It may not be amiss perhaps to caution the reader that he allow not the book to obtain by implication, either from physiology or from psychology, more authority than it is fairly entitled to ; I desire only that it may stand on its own bottom as an exposition of the aspects, be they right or wrong, in which the author's study and reflection have led him to view the matters which are discussed in its pages.

Chapter I. On The Method Of The Study Of Mind

Aspects of nature terrible to man in the infancy of thought ; whence superstitious feelings and fancies regarding nature. As these disappear metaphysical entities are assigned as natural causes, and man deems himself the " measure of the universe." Finally, the interrogation and interpretation of nature, after the inductive method, begin ; fruitful results of this method. Its adoption was the extension to the intellect of the law of internal adaptation to external relations. Any proposition concerning the unconditioned or absolute is nonsense. Is the inductive method, objectively applied, available for the study of Mind ? Difficulties in the way of such application. Development of biography, and absence of any progress in metaphysics, are evidences of its value. Discussion of the claim of Psychology to be inductive. Its method of interrogating self-consciousness palpably inadequate ; contradictory results of its use, and impossibility of applying it inductively. Observation of animals, of children, of the lower races of men, and of insane persons has been entirely neglected. Self-consciousness unreliable in the information which it does give, and incompetent to give any account of a large part of mental activity : gives no account of the mental phenomena of the infant, of the uncultivated adult, and of the insane ; no account of the bodily conditions which underlie every mental manifestation ; no account of the large field of unconscious mental action exhibited, not only in the unconscious assimilation

CONTENTS.

of impressions, but in the registration of ideas and their associations, in their latent existence and influence when not active, and in their recall into activity ; and no account of the influence organically exerted upon the brain by other organs of the body. Mind a consensus of affective, intellectual, and active functions, and the basis of the affective functions is in the organic life : mind a direct function of brain, but every organic function represented in the brain. Defects of psychological nomenclature. Incompetency of self-consciousness further displayed by examination of its real nature ; its method to be dethroned, not discarded. Physiology cannot any longer be ignored ; henceforth necessary to associate the Physiological with the Psychological method ; the former being really the more important and fruitful method. The study of the plan of development of Mind, the study of it forms of degeneration in the insane and in criminals, the study of its progress and regress, as exhibited in history, and the study of biography, should not be neglected. The union of empirical and rational faculties, really advocated by Bacon as his method, is strictly applicable to the investigation of mental as of other natural phenomena. Development of mind in nature a process of organic evolution : unity and continuity in nature. The question of relative value of inductive or deductive reasoning often a question of the capacity of him who uses it ; difference between genius and mediocrity. Conclusion — Notes.

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Chapter II. Mind And The Nervous System

The term " Mind " used in different senses : in its scientific sense, as a natural force ; and in its popular sense, as an abstraction made into a metaphysical entity. The brain certainly the organ of the Mind, and the nervous cells the immediate agents of mental function. A correlative change in nerve element accompanies each mental state ; chemical composition of nerve element being extremely complex and unstable. Mental power an organized result in the proper centres— a mental organization. No nerve in lowest animal forms ; perception of stimulus being the direct physical effect in a homogeneous substance. The differentiation

CONTENTS.

of tissues in higher animals demands special means of intercommunication : the nervous system, at first very simple, subserving this function. With increasing complexity of organization, a corresponding complexity of the nervous system. Organs of special senses appear, in very rudimentary form at first, by differentiation of the general sense of touch ; corresponding central nervous ganglia constitute entire brain in Invertebrata. Sensorimotor function. Discriminations of organic susceptibility or sensibility. Relation of consciousness to sensibility. Rudiments of cerebral hemispheres and rudimentary ideation and emotion in fishes. Convolution of the grey matter of the hemispheres in the higher mammals, and corresponding increase of intelligence in them. Differences in the size of the brain, and in the complexity of its convolutions, in different races of men, and in different individuals of the same race ; corresponding differences in intellectual development. Human embryonic development conforms with general plan of development of Vertebrata. Discrimination of nervous centres : (a) primary, or Ideational ; (b) secondary, or Sensorial ; (c) tertiary, or Reflex ; (d) quaternary, or Organic. The evidence of the different functions of these centres is anatomical, physiological, experimental, and pathological. Lockhart Clarke on the structure of the convolutions in man. Discriminating observation of mental phenomena necessary, and metaphysical conception of Mind no longer tenable. Definitions of mind. Mind never met with apart from brain. Differences of matter in dignity and corresponding modes of force. Mind the most dependent of all the natural forces ; relations of mental force in nature. Concluding remarks. — Notes. Page']'] — 135

Chapter III. The Signal Cord And Reflex Action

Spinal cord not a conducting organ only, but contains nervous centres of reflex or automatic movements. Earliest movements of infant are reflex. Illustrations of reflex movements in the decapitated frog. Pfliiger's experiments on the frog, and discussion of the theory that the spinal cord has sensorial functions. So-called design of an act not necessarily evidence of will or

CONTENTS.

consciousness. Examples of inhibitory function. The nature of the idea of design. Spinal cord is educated, and becomes the centre of many acquired or secondary automatic movements ; illustrations. The motor faculties mostly acquired in man by education and exercise, but innate in many animals. Bearing of instances of acquired adaptation of means to end on the doctrine of final causes. Motor faculties are exhausted by exercise, and require periodical rest for restoration of power by nutrition. Quantitative and qualitative relation of reaction to the impression. Innate potentiality of nerve-element, and acquired potentiality. Hereditary transmission of acquired faculties implants the germ of innate endowment. Continuous function of spinal cord : it acts (a) on muscles ; (b) on vessels : (c) on elements of a tissue; (d) on other nerve-centres. Pfliiger's laws of reflex movements. Causes of disorder of function of spinal cord : (a) original differences of constitution ; (l>) excessive action ; (c) quantity and quality of the blood ; (d) eccentric irritation ; (e) interruption of its connection with the brain. Close sympathy between different parts of the nervous system. Clear conceptions of the functions of spinal centres indispensable to the study of the functions of the higher nervous centres. — Notes Pqgc 136—185

Chapter IV. The Sensory Centres And Sensation

Collections of grey matter constituting the sensory ganglia intervene between the spinal centres and the supreme hemispherical ganglia. Sensorium commune. Anatomical relations of different grey nuclei yet uncertain, but nerve-fibres certainly connected with their cells. Sensory ganglia with connected motor nuclei the centres of independent reaction— of sensori-motor movements : examples. Such movements are primary and secondary automatic : examples. Instinctive acts of animals are sensori-motor. Relation of consciousness to sensori-motor action : examples to illustrate this relation, and discussion of them. Greater acuteness of sense in animals than in man, and consequent reactions

CONTENTS.

to impressions of which he is not sensible. Development of sense in man by special cultivation. The origin and nature of instincts. The law of heredity, and the law of variation. Transformation of rational into instinctive acts. Relation of sensation to perception. The dawn of perception. The ideas of object and subject : the conception of the ego. Development of perception by synthesis of sensations. Sensations act as symbols in sensori-motor action. Composite nature of mature sensation. The idea of organization necessary to the just interpretation of sensation ; assimilation and differentiation. No positive evidence of intelligence and volition in the sensory ganglia : uncertain whether they possess consciousness or not. The division made between psychology and physiology is artificial. Consciousness a concomitant of mental function, not the essential factor in it. Subordination of the sensory centres to the cerebral ganglia. Causes of disorder of the sensory ganglia : (a) original defects ; (&) excessive stimulation ; (c) quantity and quality of blood ; (J) reflex irritation ; (<■) influence of cerebral hemispheres (?). Concluding remarks on the analogy between the functions of the sensory centres and of the spinal centres. — Notes.

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Chapter V. The Supreme Cerebral Centres And Ideation

Cortical centres of the hemispheres the centres of Ideation. Emotion and volition. Speculations concerning the functions of different convolutions. Pathological observations and inferences. Experiments on animals, and the results. Anterior convolutions are connected with motor, posterior with sensory, tracts. Path of a psychical reflex act. The cerebral correlate of idea. Formation of concrete and abstract ideas. Animals have not abstract ideas, and the lowest savages have few or none. The so-called fundamental or innate ideas. The probable mechanism of ideation, and of the formation of concepts from precepts. Reflex cerebral function — how far an explanation. Different modes of operation of idea : (a) on movements, voluntary and involuntary, conscious and unconscious ; (l>) on the sensory ganglia, — physiologically,

CONTENTS.

as a regular part of mental function ; pathologically, ill the production of hallucinations ; {c) on the functions of nutrition and secretion : illustrations ; {d) on other ideas : reflection or deliberation. Relation of consciousness to Ideational activity. Comparison of ideas with movements in regard to their association, their relation to consciousness, the time required for their performance, and the limited power which the mind has over them. The nature and influence of attention : voluntary and involuntary attention. Motor innervation an essential factor in attention. The physical conditions of an act of attention. Localization of consciousness in the brain. The character of the particular association of Ideas determined by (a) the individual nature, (l>) special life-experience. General laws of association of ideas. Fundamental or innate ideas. The uniformity of nature. Acquisition of ideas through the accumulated experiences of the race and of the individual. The individual's particular association of ideas — need of an individual psychology. Concluding remarks on the illustration of the law of progress from the general to the special in development, afforded by the development of ideas. — Notes Tage 259 — 347

Chapter VI. On Emotions Or Affections Of Mind

Relation of emotion to idea. Emotions are based in the organic life. Influence of state of nerve-element upon emotion. Idea favourable to self-expansion is agreeable ; an idea opposed to self-expansion is disagreeable or painful. Appetite or desire for agreeable stimulus, and repulsion to or avoidance of painful stimulus, as motives of action. Desire is self-conscious appetite. The operation of the sexual appetite. Equilibrium between individual and his surroundings not accompanied with desire. Desires furnish the impulses to action ; the function of the intellect is regulative. Character of the emotion determined by the nature of external stimulus, and by the condition of the nerve-element, original and acquired. Original nature as determined by [a) the race ; (i) the culture ol the epoch ; (e) ancestral qualities ; (J) bodily temperament. The ccensesthesis. The mental or psychical tone. The complex nature of emotional

CONTENTS.

aptitudes, and their resolution or retrograde metamorphosis. Effects of organic viscera upon the emotions ; such effects are complex and non-intermittent, and cannot be studied by the subjective method. Influence of condition of blood upon the emotional tone. The expressions of the emotions : (a) in muscular movements ; (b) in changes of nutrition and secretion ; (c) in ideational activity. Action of disordered emotion. Emotions and passions. The evolution in the mental life of the fundamental instincts of self-preservation and propagation. The moral feeling — its origin and development. The moral law and the law of natural selection. The progress from the general and simple to the special and complex, in the evolution of the emotions. — Notes Page 348 — 40S

Chapter VII. On Volition

Will, like every other natural force, has a cause. Free-will or necessity : discussion of question. The reason and utility of the doctrine of free-will. The will not a single, undccomposable faculty of uniform power, but varies as its cause varies : differs in quantity and quality, according to the preceding reflection. According to the common view of it, an abstraction is made info a metaphysical entity. The design in the particular volition is a result of a gradually effected mental organization : a physical necessity, not transcending or anticipating, but conforming with, experience. Erroneous notions as* to the autocratic power of will. Its actual power considered (1) over movements, and (2) over the mental operations. I. Over movements : (a) no power over the involuntary movements essential to life ; (/') no power to effect voluntary movements until they have been acquired by practice ; (c) cannot control the means, can only will the event. z. Over mental operations : (a) the formation of ideas and of their associations independent of it ; (l>) its impotency in the early stages of mental development — in the young child and in the savage ; (c) cannot call up a particular train of thought, or dismiss a train of thought, except through associations of ideas which are beyond its control, and sometimes not at all. As many centres of volitional reaction in the brain as there are centres of

CONTENTS.

ideas. Volition built up from residua of previous volitions of a like kind. Volitional control is an instance of inhibitory function in the highest nerve-centres. To the freest action ot the will there are necessary an unimpeded association of ideas and a strong personality. Character not determined by the will, but determining it in the particular act. Relation of emotion to volition. Character determines belief as well as conduct. Modification of character. The history of a man declares his character. Differences in the quality and energy of the will. The character of the reformer, and the conditions of a successful reform. Extensive and intensive reformers . Will the highest force in nature ; its highest function creative— initiating a new development of nature.— Notes ^^409—462

Chapter VIII. On Actuation

Movement follows sensation. Movements leave behind them residua in the motor centres, whence a repository of latent or abstract movements. Motorium commune. Motor residua or intuitions intervene between motive and act, and are related to conception on the reactive side as sensation is on the receptive side. Actuation proposed for the psychological designation of this department. Motor intuitions mostly innate in animals, acquired in man. Illustrations from vision, speech, the phenomena of hypnotism, paralysis, insanity, &c. The effects of bodily attitudes upon mental states. The acquisition of speech. Aphasia : the pathological conditions of its phenomena, and their signification in relation to motor intuitions. Condilion of intelligence in aphasia. Thought possible without verbal language. Motor hallucinations. Co-ordinate convulsions. The muscular sense : its relation to the motor intuitions, and the essential part which it plays in mental function. Morbid disorder of the muscular sense. The will acts upon muscles indirectly through the motor nervous centres. Orderly subordination of nervous centres in the expression of the will in action. Natural differences between different persons in the power of expression by speech or otherwise. The origin, nature, and development of language. — ■ Notes Page 463— 511

CONTENTS.

Chapter IX. On Memory And Imagination

Definition and organic condition of memory. Memory exists in every organic element of the body — an organic registration of impressions. Conception of a mental organization necessary to an understanding of its phenomena. Relation of consciousness to memory. No memory of that which we have not had experience of, and no experience ever entirely forgotten. Physiological ideas of assimilation and differentiation necessary to the interpretation of its formation. Memory and recollection. Consciousness of the possession of what we do not actually remember. Imagination : its nature and function. The conditions of its highest development. Relation of memory to imagination. Fancy. Power of imagination built up by the assimilation not only of the like in ideas, but also of the relations of ideas. The one-making faculty. Its productive or creative power is, in its highest display, involuntary and unconscious : it is the supreme manifestation of organic evolution. Differences in the character of memory in different persons. Manifold disorders to which memory is liable. The memory of early youth and of old age. No exact memory of pain : why? — Notes Page ^iz — 540

THE

PHYSIOLOGY OF MIND

Chapter I. On The Method Of The Study Of Hind

Faust.

The right estimate of his relations to external nature har ever been to man a matter of difficulty and uncertainty In the savage state of his infancy he feels himself sc little in the presence of nature's vastness, so helpless in conflict with its resistless forces, so overawed by the spectacle of its serenely inexorable course, that he falls down in abject prostration before its various powers The earth of a sudden heaves beneath his trembling feet and his shattered dwellings bury him in their ruins ; the swelling waters overpass their accustomed boundaries and indifferently sweep away his property or his life ; the furious hurricane ruthlessly destroys the labours of years; and famine or pestilence, regardless of his streaming eyes and piteous prayers, stalks in desolating march through a panic-stricken people. In the deep consciousness of his individual powerlessncss he falls down in an

THE PHYSIOLOGY OF MIND. [chap.

agony of terror and worships the causes of his sufferings : he deifies the powers of nature, builds altars to propitiate the angry Neptune, and, by offering sacrifices of that which is most dear to him, even his own flesh and blood, hopes to mitigate the fury of Phoebus Apollo and to stay the dreadful clang of his silver bow. When the army of the King of Assyria, coming up against Jerusalem to destroy it, is devastated by pestilence, it is the angel of the Lord which goes out in the night and smites in the camp of the Assyrians an hundred fourscore and five thousand, so that they are all dead corpses in the morning. In like manner, when any case of sudden death occurs now among the Bongos of Central Africa, it is some old woman who has allied herself with the witches to do evil, for it is deemed certain that a strong man would not die unless he were bewitched.* Everything appears supernatural when man knows nothing of the natural; palsied with fear, he cannot observe and investigate ; himself he feels to be insignificant and helpless, while to nature he looks up with awe-struck apprehension as mysterious and almighty. Reflect on the fearful feelings which any apparent exception to the regular course of nature — the appearance of a comet, the occurrence of an earthquake or of an eclipse — even now produces in many uncultivated minds, on the superstitious dread which follows such unfamiliar event, and it will not be difficult to realize the extreme mental prostration of primitive mankind.

Through familiarity, however, consternation after a while subsides, and the spirit of inquiry follows upon that of reverence; the prostrate being rises from his

* Schweinfurth's Heart of Africa, vol. i. p. 310. When the North American chief Picheto was one night much alarmed by the violence of the storm, he got up and offered some tobacco to the thunder, entreating it to stop.— Tanner, Narrative of a Captivity among the North American Indians, p. 136.

knees to examine into the causes of events. Experience, sooner or later, reveals the uniformity with which they come to pass; he discovers more or less of the laws of their occurrence, and perceives that he can by applying his knowledge avoid much of the damage which he has hitherto suffered — that he can, by attending to theii laws, even turn to his profit those once dreaded physical forces. Now it is that man begins to feel that he has a much higher position in nature than in his infancy he had imagined ; for a time he looks upon himself as belonging to the same order as the things around him ; and he emancipates himself in great part from the dominion of the priests in whom he had hitherto believed as the sacred propitiators of the gods whom his fears had fashioned. When his creeds are seen to spring from an imperfection of intellect, the prayers founded on them are abandoned as marking an imperfection of will.

Thales of Miletus is said to have been the first who, in this advance amongst the Greeks, laid aside the priestly character and stood forth as a pure philosopher ; and those who immediately followed him, and constituted the Ionian school of philosophy, having an instinctive feeling of the unity between man and nature, did seek objectively for a first principle of things — the cipx>? — common to him and the rest of nature. This slow and tedious method was soon, however, abandoned for the easier and quicker method of deduction from consciousness : abstractions were made from the concrete by the active mind ; and the abstractions being then projected out of the mind into objective realities, were looked upon and applied as actual entities in nature. Anaximander, diving into his own mind and finding something inconceivable there, gave to it the name of the Infinite, and, transferring it outwards, was thenceforth content to pronounce it to be the true origin of all things ; whilst Pythagoras, going perhaps still further into the unmeaning, proclaimed numbers, which are mere arbitrary symbols, to be actual existences and the essences of things.

Thus it was that man, forgetful of his early humility, rose by degrees to the creation of a god after his own image, and to the construction of the laws of an external world after the pattern of his own thoughts : he worshipped a god who was of like passions with himself, suspicious, jealous, revengeful, kindled to anger by neglect, appeased by praise and sacrifice, while such motives as he felt to influence his own actions were held also to be the principles governing the relations of external objects; natural phenomena being explained by sympathies, loves, discords, hates. As the child attributes life to the dead objects around it, speaking to them and thinking to receive answers from them, so mankind, in the childhood of thought, assigned its subjective feelings to objective nature, entirely subordinating the physical to the metaphysical : it was but another form of that anthropomorphism by which the Dryad was placed in the tree, the Naiad in' the fountain, Atropos with her scissors near the running life-thread, and a Sun-god enthroned in the place of a law of gravitation. As was natural, man, who thus imposed his laws upon nature, socn lost all his former humility, and from one erroneous extreme passed to the opposite : as once he fell abjectly down in an agony of fear, so now he rose proudly up in an ecstasy of conceit.

The assertion that man is the measure of the universe was the definite expression of this metaphysical stage of human development. But it was a state that must plainly be fruitless of real knowledge; there could be no general agreement among men when each one looked into his own mind, and, arbitrarily framing the principles of external nature out of what he thought he found there, evolved the laws of the world out of the depths of his own consciousness. Disputes must continually arise about words when words have not definite meanings •

1.1 THE METHOD OF THE STUDY OF MIND. 5

and the unavoidable issue must be Sophistry and Pyrrhonism. This has been so ; the history of the human mind shows that systems of scepticism have alternated regularly with systems of philosophy. Fruitful of empty ideas and wild fancies, philosophy has not been unlike ' those barren women who would fain have the rumbling of wind to be the motion of offspring.