THE RELATIONS OF MIND AND BRAIN.*
'THOSE researches into the brain and nervous system, which have been prosecuted with the utmost energy, and with no small measure of success, during the present century, naturally sug- gest renewed discussion of the question how thinking is related to that organic apparatus with which it is, somehow or other, associated. From the days of Hume, and earlier, the Scotch have taken creditable interest in the philosophical problem of tracking the subtle and mysterious line where matter ends, and mind begins ; and it was time that the most metaphysical of British Universities should give us something fresh upon the subject. Dr. Calderwood goes over the ground with patient industry, with exemplary care, comprehensively, candidly. He tells us—nay, by a succession of very useful illustrations, he lets us see—what the anatomists and physiologists have been doing in this most difficult and most interesting pro- vince of scientific exploration. Turner, Quain, Wagner, Maudsley, Ferrier, Carpenter, Huxley, are put under contribu- tion, and he is equally conversant with the comments made upon the results of their investigations by such writers as G. H. Lewes and Professor Bain. When he has shown us all, however, -that the indefatigable anatomists and physiologists of an age when the enthusiasm of science is a thousand times more widely -diffused, and even more impassioned, than the enthusiasm of poetry, have been able to accomplish in the way of explaining the tie between consciousness and matter, we are constrained to -confess that it recalls to us Voltaire's summary of the meta- physical discoveries of the sages of all time,—Tres pea de chose. Spots have been marked on this lobe of the brain and on that which, when electrically stimulated, produce twitchings of the limbs. Other lobes of the brain have been distinguished—the frontal and the occipital—which do not respond to the electrode. Fine threads of white or grey matter have been traced from eye -andear and nostril to the brain, and it has been shown that, when these fine threads are cut, the eye no longer sees, the ear no longer hears, the nostrils no longer smell. Some of the fine threads in question have been proved to carry messages in from the finger-tips or toe-surfaces to the nerve-centre ; some of them have been proved to carry messages out from nerve-centre to toe and finger,—the former have been called sensory nerves, and the latter motor nerves. We know how the grey matter -and the white matter are placed in relation to each other under the panoply of the skull. We are familiar with the -cerebrum and the cerebellum, the corpus callosum and the medulla oblongata ; we can trace the fissure of Rolando, the Sylvian fissure, and a variety of sutures and convolutions. This, no doubt, is much. All honour to the explorers of these -dim continents, the Mungo Parks and Livingstones of this un- travelled Africa. But when we have heard the whole, we are bound to confess, with Professor Tyndall, that for us, as for our fathers, when speculative philosophy began, 3,000 years -ago, "the passage from the physics of the brain to the corre- sponding facts of consciousness is unthinkable."
It is mortifying to the self-conceit of genius, and. humbling to the pride of science, to know that the difficulty in question, on which the disciplined observation of many generations has been unable to shed one ray of light, can be appreciated by -any intelligent boy, and must have presented itself in the -earliest dawn of philosophy. Take the phenomenon—few, surely, are more rudimentary—which we call physical pain. Every one knows what that means, and yet the most acute philosopher will be puzzled if he attempts to take the expres- sion to pieces, and to assign a definite and rational sense to it. What idea have we of pain, except as a state of consciousness ? Absolutely none. It is exclusively in consciousness that we become aware of pain, as suffered by ourselves ; it is solely by inference from the signs of consciousness, sympathetically interpreted, that we affirm pain to be a fact in our fellow-men and the animals. Out of consciousness, is out of pain. That is a universal rule. We absolutely cannot think of matter feeling apart from consciousness. Has, then, the expression "physical pain," no meaning ? It were rash to answer in the affirmative. In the first place, we localise pain in various parts of the body. We are not more certainly conscious of pain than we are that the pain is in our ear, our throat, our leg, our arm. This localisa- tion is plainly physical. In the second place, there are suffer- ings which we cannot localise. Sorrow for a friend is not
• The Relations of Mind and Brain. By Henry Calderwood, LL.D., Professor of Moral Philosophy, University of Edinburgh. London Macmillan and Co. 1879. placed by consciousness in any part of the body. It is only by metaphor that love is put into the heart, jealousy into the eyes. We speak, therefore, with definite and in- telligible meaning, when we say that toothache is, and that remorse is not, a physical pain. But when it is asked why and in what manner molecules, which we cannot conceive as con- scious, affect us with conscious agony, our reply is silence. We can no more imagine one molecule suffering pain than a stone suffering pain, or a plurality of molecules suffering pain than a heap of stones suffering pain, or a particular arrange- ment and organisation of molecules suffering pain than a hurdy- gurdy wincing under its own cruel music.
So far as experiment affords any guidance in the case, it seems to negative the physicalness of the pain. When a finger is put into the flame of a candle, the pain does not follow in an indivisible moment of time. Were the arm to be cut away by a cannon-ball, so immediately after the finger had touched the flame that there had not been time to send on the message of the burning by the nerve to the brain, the pain in the finger would never be felt at all. This accounts for the well-known fact that gun-shot wounds are painless at the instant when the ball enters. A registering process—we call it a registering process, but we do not in the least know what it is—must take place in the nerve-centre, that is to say, in the brain, before the pain is felt. But it is never felt except in the finger. The brain itself does not feel. And yet, are we not bound to admit that the pain cannot be in the molecules of the finger, since these mole- cules are acted on by the flame or the shot without one twinge of pain, until the message has been transmitted to the nerve- centre? Do we not seem to be shut up to the conclusion that the pain is solely in consciousness, that matter is exclusively an instrument in the case, and that the real cause of the pain is the quality or nature of the awakening of consciousness? We are as far, however, as before from an answer to the question how a disturbance among molecules can awaken a painful consciousness. Nor is the difficulty lessened by the fact that consciousness can frustrate molecular action. In circumstances of great excitement, as in the tumult of battle, when the attention is absorbed in fighting, and there is not enough brain-energy left to do what we have called the registration, wounds are received without any experience of pain. The physical impact could not awaken the consciousness.
So much for the mere fact of pain. How mind and matter are concerned in it is a mystery too deep for all our physicists and all our spiritists to probe. But pain is, perhaps, the simplest of all the cases in which mind and matter co-operate, or combine, in a common result. If the materialist fails to lay his grasp on anything like proof that molecules can feel pain, how strong is the probability that he will fail to prove thought, imagination, reverence, wonder, invention, to be affairs of molecular condition or arrangement ! Accordingly, we need not be surprised to find Dr. Calderwood setting in array against the materialist a multitude of objections to the hypothesis that even the initial operations of thought can be performed by nerve-cells or by nerve-fibre. Accepting from Profeasor Bain the position that "discrimination is the very beginning of our intellectual life," and conceding to physiologists all they can pretend to make good in relation to nerve-fibre, he points out that, in merely touching successively, with the fore-finger, "a sheet of note-paper, a table-cloth, and an ink-bottle," we have discrimination of sensations, and that no material apparatus exists for the performance of this discrimination. "While sensation is only a particular and single experience, in accord- ance with the singleness of nerve-action on which it depends, consciousness distinguishes one sensation from another,—an exercise for which we have no provision in nerve-action." "The facts carry us quite beyond mechanical contrivance, inasmuch as one thing not only follows another, but one thing is compared with another ; that is, there is not only one thing distinct from another, but one thing is distinguished from another." Does the materialist allege that the successive sensations are ana- logous to electric shocks ? He is asked whether one electric shock has the capacity of comparing itself with another. Does he insist that the successive sensations leave indentations in the sensory cell? The reply is that even if this were proved—and we need scarcely say that there is not a shadow of evidence that the indentations exist—there is no form of inscription known or conceivable, in which each word is its own grammatical critic and interpreter, discriminating itself from the word going before and the word coming after, and connecting itself with both. If molecules are thus shown to be incapable of the simplest opera- tions in which thinking takes its rise, it may be imagined with what ease and conclusiveness Dr. Calderwood succeeds in showing that molecules cannot rationally be credited or debited with all that the mind of man has achieved in morality, religion, science, literature, and art.
Shall we say, then, that the victory of the believer in spirit, the advocate of mind, the immaterialist, or whatever else we may call him, over the materialist, is complete ? Shall we, with Dr. Calderwood, lay down the proposition as really too plain for dispute, that "mind is a superior order ef existence, per- forming work unapproachable under the laws of nerve-action," and that "the immateriality of the rational nature is clearly implied in the forms of activity which are peculiar to it ?" Shall we decide that mind is the man, and that matter, in bone and muscle, in brain and nerve, is but the organ of spirit? It seems not unreasonable to answer, yes. For the distinctive position of materialism, that matter takes the initiative in willing, thinking, feeling, or acting, there is not a trace of evidence. No doubt it is possible for the materialist to maintain that evidence in its support may one day be forthcoming, and that research in the region of the brain has unveiled an unoccupied territory, in which the evidence wanted may sooner or later be found. "A central governing power" is gener- ally admitted to have some special connection with the frontal lobes of the cerebrum. Remove these lobes, the animal, pre- viously alert and energetic, becomes apathetic. Its power of will has vanished. These lobes do not respond, as do the lobes connected with the movements of the limbs, to electric stimula- tion. It is, therefore, certain that, neither dynamically nor in- strumentally, is electricity the organ of thought. The materialist suggests that "beyond the range of season-motor activity, there are still other correlated cells and fibres by the action of which thought and volition are induced." But this is a purely hypothetical notion, and cannot stand for one moment against the clear consciousness of will as a spiritual agent. Even if the intellectual-volitional or volitional-intellectual fibres and cells dreamed of by the materialist were discovered, he might be challenged to prove that they acted dynamically, not instru- mentally,—that they gave orders to the spirit, instead of taking orders from it.
Let us not, however, proclaim too jubilantly the sovereignty of mind over matter. That sovereignty is of a strangely qualified, limited, perplexing kind. If we put out of consideration, for argument's sake, the proof, sound or fallacious, that extra-human existences of a spiritual order act, or have acted, directly on the soul, there is no particle of evidence that mind can act on mind, except by means of matter. The materialist may allege that he, at least, sees, feels, touches matter, and may challenge the immaterialist to say whether he ever saw or touched a spirit. Nay, he may reduce his opponent to painful straits, by simply insisting upon an articulate statement as to what spirit is. The immaterialist must have recourse to a series of negatives, suggested by particular aspects or properties of matter. Spirit is not tangible, is not ponderable, is not coloured, is not extended. Is the primal fount, then, of all the energy in the universe to be described only, the materialist may ask, by an amplified confession that it is not describable ? The immaterialist is forced to lay hands on the matter he has been spurning, and to turn spirit into something which, though inconceivable, may yet be spoken about, by arraying it in the imagery of matter. Though mind is not extended, he says that it collects itself ; though it is imponderable, he says that it is light or heavy ; though it is without colour, he says that it is brilliant or sombre ; though it has no dimensions, he calls it profound or shallow, high or low, cold or hot, tranquil or vol- canic. It is easy to prove, against Professor Bain, that there can be no such thing as a mental side and a physical side of the same phenomenon, inasmuch as a physical side can always be measured, whether in inches or the millionth-parts of inches, whereas it is impossible to attach anything like sense or mean- ing to such an expression as half an inch of feeling or a yard of the spiritual power by which we solve a problem of Euclid. But it is quite impossible to find any description of a mental phenomenon that shall not be liable to the same objection,— namely, that it denotes by material imagery what can be known only by its comprehensive negation of all material qualities.
Nor is this the worst. We might be content to speak of mind in terms borrowed from matter, if we could be sure of exempting mind, as an actual living entity, from bondage
to matter. But how is this to be done ? Dr. Calderwood does- not doubt that, though the physiological exhibition of the proof is very far from complete, proof is possible that every mental state is associated with some corresponding molecular state. The mind can control the body to a marvellous extent, but the strongest mind in the species would succumb to half-a-gallon of whiskey or a pint of hemlock-juice. Dr. Calderwood tells us of a clergyman who became morally scandalous, was subjected to ecclesiastical discipline, and ended in an asylum. After death his brain was found to have been wasting, the membrane adhered to the grey matter, and the blood-vessels were like quills. He mentions another case of a man who was misan- thropic, queer, morosely solitary. This disagreeable person had his head accidentally broken. A lot of brain protruded and sloughed off. On regaining his health, he was cheerful and sociable, married a wife, and lived, we presume, happily ever after. No doubt is suggested by Dr. Calderwood as to the physical explanation of both these cases, and who will maintain that the influence could, in either, have been controlled by the will? Intoxication and many forms of lunacy exhibit will and reason in chaotic disorder ; and many a man has dreaded the moment when, from growing physical malady, the atmosphere of madness would envelope him, and he would will, with burn- ing intensity, to kill his neighbour or himself. While, there- fore, we have a right to say that the brain and the body in general are but the organ of mind, we must admit that the way in which mind and its organ are connected is something sal generis, something unique, something unthinkable.. There- is no other instance known in which the state of the organ or instrument imparts itself to the power using the organ. The telegraphic wires may be out of order, but that affects only their capacity to carry messages, not the power of the telegraphist to send them. An inflamed brain maddens a man. On the whole, however, Dr. Calderwood seems to us to make good his position "that man possesses a higher order of life than the physical, yet in entire harmony with his physi- cal organism, and so governing it that the two constitute a unity of being." If abnormal states of mind and body, such as those produced by intoxication or disease, arc left out of account, this will go far to explain the phenomena presented by the union of mind and body.
Dr. Calderwood's is an able and excellent book, amply de- serving perusal. We think, however, that his eye is not quite- sharp enough in discerning the difficulties of his subject, and that his logic is not always masterly in dealing with them. His account, for example, of the cerebral operations of animals is eminently interesting, but he is nothing short of obtuse in his non-perception of a difficulty which most of his readers must agree with us in feeling,—namely, that of establishing, in- view of his own facts, any difference of essential importance between the mind of man and the mind of animals. He- states, for instance, the following facts as perfectly an- thentic. A dog belonging to a United Presbyterian Minister killed the fowls while the family were at church, and buried them in the garden. The bodies were found. " The dog," says Dr. Calderwood, "was taken to the garden, and im- mediately confessed his guilt. His master took him to his library, and having shut the door, began a reprimand after this fashion:—' What a wicked thing you have done in murdering the liens! You are a minister's dog, and should have been an example to other dogs, instead of doing such a thing as this. Then, this is Sabbath-day, and the deed is all the worse on ac- count of the day on which it has been done.' rhus admonished,. the dog was put out at the door, and the door shut. Next morning he was found dead." A veterinary surgeon was con- sulted, and declared that the dog had died of a broken heart.- So far, Dr. Calderwood. We can only say that, if the minister and the veterinary-surgeon spoke the whole truth, and nothing but the truth, and were correct as to the dog's comprehension of the reprimand and consequent death, the dog was as truly a reasoning and feeling animal as any minister that ever signed the Confession of Faith.
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