Principles of mental physiology : with their applications to the training of the mind, and the study of its morbid conditions

Front matter

PRINCIPLES OF

MENTAL PHYSIOLOGY.

EXTRACTS FROM PRESS NOTICES OF THE FIRST EDITION.

Preface

my own Psychological views since I first put them forward, but, on the contrary, having found them confirmed and extended by the experience and reflection of twenty years, I set myself to revise my former exposition of them, with the idea of simply introducing such illustrations as might lead to the more ready apprehension of the principles I aimed to enforce, and of filling-up such deficiencies as it might seem most desirable to supply. But, as I proceeded with the work, I found it grow under my hands ; and it has at last so far exceeded the limits originally contemplated, as to become unsuitable to the Series for which it had been designed, from which it has been accordingly withdrawn, for issue as an independent Treatise.

I now send it forth as a contribution to that Science of Human Nature, which has yet (as it seems to me) to be built-up on a much broader basis than any Philosopher has hitherto taken as his foundation. To the character of a System of Psychology, this treatise makes no pretension whatever ; being simply designed to supplement existing Systems of Physiology and Metaphysics, by dealing with a group of subjects, which, occupying the border-ground between the two, have been almost entirely neglected in both. Hence, in treating of Sensation, I have not entered into those details on the Physiology of the Senses which are readily accessible elsewhere ; but have especially applied myself to the elucidation of the share which the Mind has, not only in the interpretation of Sense-impressions, but in the production of Sensorial states not less real to the Ego who experiences them than are those called-forth by external objects,

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— a topic of the greatest importance in reference to the value of all Testimony given under a Mental preconception. And, in like manner, I have done no more than enumerate a large proportion of those principal modes of Mental activity, which are commonly designated as Intellectual Faculties, Propensities, and Emotions; in order that I might have space to bring into clear view that distinction between their automatic and their volitional operation, which has long appeared to me the only sound basis, on the one hand, for Education and Self-discipline, and, on the other, for that Scientific study of the various forms of abnormal Mental activity, which, rightly cultivated, is probably the most promising field of Psychological inquiry.

It would be ungrateful were I not to take this opportunity of renewing the expression of the special obligations I owe, in the original construction of my “fabric of thought” on this great subject, to the writings and conversation of my valued friends the late Sir Henry Holland, Professor Laycock, Dr. J. D. Morell, and Dr. Noble. — To the first of these it had been my intention to dedicate this Treatise, the title of which he had kindly permitted me to borrow from one of his own ; and I have gladly, therefore, complied with the wish of his Family, that I should dedicate it to his Memory. No one can know the wonderful suggestiveness of Sir H. Holland’s scientific writings, who has not had the occasion (which has often occurred to myself) to trace back to them some of the best of the thoughts which he had honestly believed to be his own. This I have found

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particularly the case in regard to the subject of Attention ; the fundamental importance of which in relation to the Will, I first learned from him to appreciate.

Other obligations to later writers on Psychology are noted in their proper places : but all the general doctrines of importance herein set forth, will be found, I believe, either explicitly stated or clearly indicated in my original Outline; and in their fuller development I have preferred to draw either upon my own mental experience and that of others, or upon that very large group of abnormal phenomena, which has not yet (so far as I am aware) been discussed by any professed Psychologist, but of which the careful study seems to me absolutely essential to a due understanding of the relation of the Will to the Automatic activity of the Mind, and of both to the Physiological Mechanism. Some apology may be thought due for the introduction of so many old and familiar illustrations ; and especially for such numerous citations from the well-known work of Dr. Abercrombie on “ The Intellectual Powers.” But I have not hesitated to bring in old stories whenever they were specially to the point ; and I believe that in many instances I have been able to give them an entirely new application.

In conclusion I venture to ask for a fair measure of indulgence for such errors and shortcomings (especially on the Psychological side) as will doubtless be discovered in this Treatise ; on the ground that it has been impossible for me to devote to it that continuous thought, which is especially required for the systematic prosecution of any inquiry of this kind, and for the exposition of its results.

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Had I kept tlie work back longer in the hope of a more favourable opportunity for its production, I might have altogether lost, with the advance of years, the power of producing it. Such as it is, I offer it, on the one hand, to those who are interested in the progress of Psychological Science, and are disposed to widen its area of investigation ; * and, on the other, to those who desire a definite basis and aim in the Intellectual and Moral training either of others or themselves ; — with the hope that I may at any rate stimulate some other investigator to follow-out the path I have tried to open, who shall bring to the Scientific interpretation of Physiological phenomena a knowledge of Metaphysics to which I can lay no claim, and a Mind better trained in abstract thought.

February, 1874.

TO THE FOURTH EDITION.

Since the first issue of the following Treatise, the question of “ Human Automatism” has largely engaged the attention of that increasing portion of the public mind which interests itself in scientific enquiry. The Address of the eminent Physicist who occupied the Presidential chair at the Belfast Meeting of the British Association, embodied a philosophical creed of which it seems a necessary corollary, that all Mental as well as bodily activity, being the outcome of the “ potentialities ” of Matter, is subject to Physical conditions alone. — The distinguished Biologist who brilliantly expounded at the same Meeting the Cartesian doctrine that “ Animals are Automata,” explicitly maintained (in direct opposition to Descartes himself) that Man is only a more complicated and variously-endowed Automaton : his bodily actions being determined solely by Physical causes ; the succession of his Mental states depending entirely upon the molecular activities of his Cerebrum ; and the movements he is accustomed to regard as expressing his feelings, or as executing his intentions, having their real origin in Brain-changes, of which those feelings and intentions are the mere concomitant “ symbols xiv Preface to the Fourth Edition.

in consciousness.”* — Professor Huxley’s pronunciamento was soon followed by that of an able Mathematician, who brought to that profoundly difficult problem of u Body and Mind ” which has exercised the greatest intellects from Aristotle to J. S. Mill, the training of a skilled athlete, who knocks down with one vigorous blow any opponent unprepared for his peculiar mode of attack. Belying exclusively upon Physical experiences, Professor Clifford affirmed without the smallest hesitation, -j* that as the only thing which can possibly be conceived to influence Matter is either the position or the motion of surrounding matter, the statement “ that the Will influences Matter ” is simply “ nonsense;” an affirmation which assumes that Professor Clifford knows all about matter and its dynamical relations, and therefore has an unquestionable right to say that Mankind at large are wrong in the conviction that the movements of their Bodies are in any way directed by their Minds.

From the confidence with which what are asserted to be the inevitable conclusions of Physiological science, are now advanced in proof of the doctrine of Human Automatism, it might be supposed that some new facts of peculiar importance had been discovered, or some more cogent deductions drawn from the facts previously known. But after an attentive re-examination of the whole question, I find nothing in the results of more recent researches to shake the conviction at which I arrived nearly forty years ago,t of the

* “ Fortnightly Review,” November, 1874, p. 577.

+ “Fortnightly Review,” December, 1874, p. 728.

£ “On the Voluntary and Instinctive Actions of Living Beings,” in the Edinburgh Medical and Surgical Journal, No. 132 (1837).

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xv existence of a fundamental distinction, not only between the Rational actions of sentient beings guided by experience, and the Automatic movements of creatures whose whole life is obviously but the working of a mechanism, — but also between those actions (common to Man and intelligent brutes) which are determined by a preponderating attraction towards an object present to the consciousness, and those (peculiar, as I believe, to Man) in which there is, at one stage or another, that distinct purposive intervention of the self-conscious Ego which we designate Will, whereby the direction of the activity is modified.

What modern research seems to me to have done, is to elucidate the mechanism of Automatic action ; to define with greater precision the share it takes in the diversified phenomena of Animal life, psychical as well as physical ; and to introduce a more scientific mode of thought into the Physiological part of the enquiry. But in so far as those who profess to be its expositors ignore the fundamental facts of Consciousness on wdiich Descartes himself built up his philosophical fabric, dwelling exclusively on Physical action as the only thing with which Science has to do, and repudiating the doctrine (based on the universal experience of mankind) that the Mental states which we call Volitions and Emotions have a causative relation to Bodily changes, they appear to me to grasp only one half of the problem, to see only one side of the shield (§ 2). That the principle of the Conservation of Energy holds good not less in the Living body, than in the Inorganic world, I was myself among the earliest to

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maintain.* That in the most powerful Muscular effort which can he called forth by the Human Will, there is no more a creation of Energy than in an Automatic convulsion, I believe as firmly as Professor Clifford. And that the general tendency of modern Scientific research is to extend the domain of Law to every form of mundane change, — the belief in the Uniformity of Causation being now assumed as axiomatic in all scientific procedure, — I recognize as fully as Mr. Herbert Spencer (§ 574). This tendency could not be expressed more forcibly, than in the following citation from Mr. H. Sidgwick’s recent Treatise : —

“The belief that events are determinately related to the state of things immediately preceding them, is now held by all competent thinkers in respect of all kinds of occurrences except Human Volitions. It has steadily grown both intensively and extensively, both in clearness and certainty of conviction, and in universality of application, as the human mind has developed and human experience has been systematized and enlarged. Step by step, in successive departments of fact, conflicting modes of thought have receded and faded, until at length they have vanished everywhere, except from this mysterious citadel of Will.”f

Before enquiring, however, whether there is adequate ground for regarding the Human Will in this exceptional light, it may be well to consider what basis there is for the assumption that the range of Physical Causation extends itself from the sphere of Matter to that of Mind, — in other words, that Moral Causation and Physical Causation are convertible terms.

It may be fairly urged, on one side, that the tendency of

* “ On the Mutual Relations of the Vital and Physical Forces,” Philos. Transact., 1850.

f “The Methods of Ethics,” p. 47.

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XVII modern Scientific investigation has been to show that a verylarge proportion (if not the whole) of those changes whose succession constitutes our Mental life, are determinately related, on the one hand, to the Mental states which immediately preceded them, and, on the other, to the Material conditions of the Bodily organism. The pure Metaphysician, who studies the “ Laws of Thought ” in the abstract, as if Man consisted of Mind without Body, no more doubts the former, than the Physiologist, who works upwards from Body to Mind, and studies the successions of Consciousness as functions of the Nervous System, can question the latter. And the Psychologist, whose object (to use the words of Mr. Herbert Spencer) is to elucidate u not the connection between internal “ phenomena, nor the connection between external phe- “ nomena, but the connection between these two con- “ nections,” and who studies the relation between Psjxhical phenomena and Physical conditions through the whole range of the Animal kingdom, interpreting these phenomena by a scientific scrutiny of his own experiences, and applying the knowledge thus gained to the explanation of the actions of organisms whose constitution resembles his own (this enquiry being the special object of the present Treatise), finds himself irresistibly brought to the conclusion that Automatism* has a very large share in the life of every Human being ; and is thus naturally led to question whether there is any part of

* In the term “ Automatism,” as used here and elsewhere, I include not merely those Bodily but those Mental activities, which are determinate! y related to (or, in other words, are caused by) previous bodily or mental activities, to the exclusion of all choice or self-direction on the part of the Ego.

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Man’s action which is exempted l'rom the Law of Physical Causation.

The corrective to this view, however, appears to me to be furnished by the intelligent study of that large class of the phenomena of Human Nature, which lies patent to every trained observer in the ordinary course of events. For the more carefully he studies these phenomena, the more clearly is he led to see that, as has been pithily said by Emerson, “ Thoughts rule the World p and that, though the spheres of moral and physical Causation impinge (as it were) upon one another, they are in themselves essentially distinct. The influence of a great Idea conceived by a thinker in his closet, in dominating the action of an entire Nation, is utterly disproportioned to any conceivable play of molecular forces that can be excited by the Physical agency of the thinker in putting his idea into speech or writing. The Moral power of the u thoughts that breathe, and words that burn” in the utterances of the Poet, cannot be correlated, like the mechanical Energy exerted by his muscles in the writing of his verse, with the quantity of food he may have consumed in their production. And the new direction that may be given to the whole course of two lives, by the faintest expression of Emotion in a tone, a look, or a touch, cannot be brought to any common measure, either with those Muscular contractions, or with those molecular changes in Nervous matter, which are the Physical causes of its manifestation.

But to this it may be replied that, even when we look at Human action from its Mental side, without any regard to

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Physical antecedents, we cannot help recognizing in it the principle of Causation by character and circumstances ; and that without the power of prediction which we derive from organized experience, as is well stated by Mr. Sidgwiek (Op. cit. p. 48), social life would be impossible. But while every one admits the existence of Uniformities in Human action which constitute the basis of our Social fabric, every one also admits that the closest observation of these Uniformities, and the most sagacious analysis of their conditions, does not justify anything more than a “ forecast ” of the course of action, either of individuals or of communities, in any given contingency. “ Who would have thought that he would have done such a thing?” is our frequent exclamation in regard to some one of whom we considered that we had a most intimate knowledge : that “ the unexpected [in Politics] is what always happens,” has passed into a proverb. It is, of course, open for the Automatist to assert that the element of uncertainty here arises, as in the case of weather-forecasts, from the complexity of the conditions, and from our imperfect acquaintance with them ; and he might fairly urge, on general grounds, that if we could grasp the whole of the antecedents, and measure the potency of each, no u unconditioned ” or self-originating element would be found to have interfered with the regular sequence of cause and effect. But he has no right whatever to assume this. The whole history of Science shows that the investigation of u residual phenomena” has been a most fertile means of discovery in regard to agencies not previously suspected. And until it shall have been proved that

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there are no Human actions which cannot be accounted for by u unconditional sequence,” such an assumption cannot he admitted as an adequate disproof of the testimony borne by Human Consciousness to the opposite effect. “ It is im- “ possible for me to think,” says Mr. Sidgwick, (Op. cit. p. 51), “ in the moment of deliberate volition, that “my volition is completely determined by my formed cha- “ racter and the motives acting upon it. The opposite “ conviction is so strong as to be absolutely unshaken by “ the evidence brought against it. I cannot believe it to be “ illusory. * * * No amount of experience of the sway

“ of motives even tends to make me distrust my intuitive “ consciousness, that in resolving after deliberation I exer- “ cise free choice as to which of the motives acting on me “ shall prevail. Nothing short of absolute proof that this “ consciousness is erroneous, could overcome the force with “ which it announces itself as certain ; and I cannot perceive “ that such proof has been given.”

It is alleged, indeed, that the belief entertained by all men — except Philosophers — in their owm freedom of choice (within certain limits) between different modes of action, is an illusion of ignorant “ common sense,” which, like the vulgar belief that the sun moves round the earth, is utterly dispelled by the light of Science. But the two beliefs rest upon an entirely different basis. The latter, like other erroneous beliefs which arise in the exercise of our senses, is an inference from the facts of Consciousness, which a more enlarged experience (such as that afforded by almost every railway-journey) show's to be untenable : the

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xxi former is the immediate affirmation of Consciousness itself, the assurance of which, its constant recurrence under a great variety of conditions only serves to confirm.

The direct Testimony of Consciousness as to any one of its primal cognitions, must be held, as it seems to me, of higher account than the deductions of Reason from data afforded by other cognitions ; constituting, in fact, a “ base “ of verification ” to which all our logical triangulation must be worked back, if we desire to test its validity. And no fact of Consciousness as to which Mankind in general is in accord, can be disproved save by the contradiction afforded by some other primary cognition of superior validity. For, as has been truly said by John S. Mill, “ feeling and “ thought are much more real than anything else ; they “ are the only things which we directly know to be “real.”* We know nothing about matter, as Berkeley demonstrated, except by inference from the manner in which its states affect our consciousness ; “ itself we do not “ perceive ; we are not conscious of it.” And hence those so-called “ experiences,” on the basis afforded by which the whole fabric of Physical Science is built up, being really nothing else than “ assumptions to account for our sen- “ sations ” (Mill), can only be accepted as valid, in so far as they accord with those primal cognitions which we cannot dissociate from our own consciousness of personal agency. Thus, for example, when Professor Clifford affirms {toe. cit.) that no interaction can possibly take place between Bodily and Mental states, — the Physical facts going along by them- * “ Posthumous Essays,” p. 202.

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selves, and the Mental facts going' along by themselves, on two utterly different platforms, — he calls upon us to receive as the indubitable teaching of Science, the result of a process of reasoning based upon one set of experiences alone ; notwithstanding that this is completely contradicted by another set, which, as appealing much more directly to our own consciousness, has a stronger claim upon our acceptance. For all Mankind — except philosophers of Professor Clifford’s school — accept it as a fact u based on the normal il experience of healthy men” that running a pin into one’s flesh is the cause of that mental state which we call pain (Huxley, Op. cit, p. 674) ; a certain neurosis , or molecular change in the Nervous system, producing a corresponding psychosis , or affection of the Consciousness. And, conversely, since all Mankind — except the followers of Professors Huxley and Clifford — accept it as a fact “ based on the normal experience of healthy men,” that the state of mind which we term Volition is the cause of the muscular movement that gives expression to it — a psychosis producing the neurosis which calls forth Muscular contraction — I cannot see that this conviction can be nullified by any inference drawn from an order of facts that is capable of an entirely different interpretation. The doctrine propounded by Professor Huxley in his Belfast lecture, that the feeling we call Volition is not the cause of the voluntary act, but the “ symbol in consciousness ” of that state of the Brain which is the immediate cause of that act (like the blowing of the steam-whistle, which signals, but does not cause, the starting of the locomotive), and that the strongest Volition

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xxiu has therefore no power in itself to call forth a movement, seems to me to find its best answer in the explicit statement which he himself put forth not many years previously, that “ the belief that our Volition' counts for something as a con- “ dition in the course of events,” is one which u can be “ verified experimentally as often as we like to try,” and therefore “ stands upon the strongest foundation upon “ which any belief can rest, and forms one of our highest u truths.” *

When we come to examine the reasons latterly assigned by Professor Huxley for giving up this assured belief, we find them mainly based on the fact that certain actions which would be ordinarily accounted Volitional (as being initiated by an intentional effort) in Man, can be performed under circumstances which strongly indicate a purely Automatic causation.

Thus it has been shown by Goltz, that a Frog from which the Cerebrum has been removed, and which (according to ordinary Physiological doctrine) has consequently lost the power of voluntary movement, will jump when irritated, the direction of this movement being affected by the incidence of light upon its eyes ; though making no effort to feed itself, it will swallow food put into its mouth, and may thus be kept alive for weeks or months ; and will utter its croak when a particular part of its back is stroked. But further, although, when put on the hand, the Frog sits there crouched, perfectly quiet, and would remain so unless stimulated to action, yet (says Professor Huxley) “ if the hand be inclined very gently and slowly, so that the frog “ would naturally slip off, the creature’s forepaws are shifted on to the “ edge of the hand until he can just prevent himself frcm falling. If “ the turning of the hand be continued, he mounts up with great care “ and deliberation, putting first one leg forward, and then the other, “ until he balances himself with perfect precision upon the edge, and

* “ Lay Sermons,” p. 160.

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“ in the turning of the hand over he goes through the opposite set of “ operations, until he comes to he seated in security upon the back of

the hand.” — ( Fortnightly lievietv, Nov. 1874, p. 567).

Now, that Man is himself continually making yet more elaborate adjustments of his muscular movements, under circumstances which forbid the idea that they are in any way directed by his Conscious Will, is expressly shown in various parts of the present work. Some of these actions, as coughing (§47) and sucking (§ 48), are originally or primarily Automatic; and can he experimentally shown not to depend upon Cerebral instrumentality, except when performed in obedience to a Volitional mandate. Others, as walking erect (§§ 16-18), are originally performed under the conscious purposive direction of the mind ; but, when they have once become habitual, they may be repeated involuntarily, and even unconsciously, by a secondary or acquired Automatism, the mechanism of which has constructed itself in virtue of the tendency of the Nervous system to grow to the mode in which it is habitually exercised (§ 278). And this is equally true of those more special activities which have been acquired by “ training,” — such as rope-dancing (§ 381), music-playing (§ 194), juggling with halls (§ 194), &c. ; for these may be performed (as we are accustomed truly enough to say) “ mechanically ” by any individual by whom they have been so habitually repeated as to have become a u second nature.”

Of this general principle, of which numerous examples will hereafter come before the reader, the following singularly curious illustration, which I have lately received from a trustworthy source (a Clergyman in the North of Enghind), may be here presented : —

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“ While I was a student in Dublin University, I was at an evening “ party at which a lady was asked to play for dancing. Unfortunately “ she had taken far too much at supper; and was, in fact, after she “ had begun to play, so drunk as to be totally unable to rise off the “ stool. I was standing near the piano, and saw her eyes close, her “ head fall forward, and give every manifestation of sleep except snore “ aloud. But her playing went on in perfect time ; and, in fact, the “ difficulty was, when she had ended a waltz or quadrille, to make her “stop; for when she was shaken out of sleep, it was evidently her “ intention to go on the whole night. To set her going again, it was “ only necessary to place her hands on the keys, and she would begin “ a new quadrille, soon again relapsing into sleep, and yet continuing “ to play well. I was studying a deep course of Metaphysics at the “time, for my degree in those subjects in Trinity College; and the “ case made a great impression on my mind. I could not account for “ it on any of my then principles ; but I see it perfectly now.”

I have recently learned, too, that it is no uncommon experience in Telegraph offices, for transmitters of messages, when they have been for some time in the service, to work the instruments without conscious thought of what they are doing. “ They read the words,” says my informant, “pass them through their minds, and transfer them to “ the sending part of the apparatus, just as unconsciously and auto- “ matically as Wheatstone’s transmitter does. I have often found “myself,” he continues, “indulging in trains of thought, or even “ listening to a conversation that might be going on near me, and yet “ continue to ‘ receive ’ and ‘ send’ just as if I was giving my whole attention to the work; and when I came to see the messages after- “ wards, I knew that they had passed through my hands only by the “handwriting. Once, indeed, when on night duty, I became com- “ pletely unconscious whilst sending a long and monotonous ‘ group ’ “ message, consisting entirely of figures, and woke up bewildered;

' ‘ and had to ask the receiving station ‘ after what ? ’ before I could “ proceed. Some clerks believe that the work is done more accurately “when done automatically; but I scarcely think this justified by “ experience.”

However strange these statements may seem, they find their parallel in our own familiar experience. For almost every one who has been much in the habit of reading aloud, is well aware that he may continue to do this with perfect articulation, punctuation, emphasis, and intonation, while xxvi Preface to the Fourth Edition.

his mind is so completely engrossed by some entirely different subject, that, until his Attention is recalled to it, lie •is no more aware that he is reading, or conscious of the guidance he has been receiving from his visual sense, than is the philosopher of the pursuance of his walk whilst his whole mind is given to the solution of some knotty problem (§1 17). The only difference between the case of the reader-aloud and that of the telegraph-clerk, is that the words whose visual pictures have fallen on the retina, are expressed in the one case by acts of vocalisation, in the other by a special kind of finger-language. So, the case of the musical performer who continued to play quadrilles in her sleep, is analogous to that of the ambulatory thinker ; a previously acquired succession of movements, once initiated, going on without conscious direction; each movement being suggested by that which preceded it, and itself suggesting the next.