1. The peculiarity of the Reflex Theory is its exclusion of Sensibility from the actions classed as reflex; in consequence of which, the actions are considered to be “purely mechanical.” No one denies that most of the reflex actions often have conscious sensations preceding and accompanying them, but these are said not to be essential to the performance of the actions, because they may be absent and the actions still take place. It is notorious that we breathe, wink, swallow, etc., whether we are conscious of these actions or not. Our conclusion therefore is that these peculiar states of Consciousness are accessory, not essential to the performance of these actions. The fact is patent, the conclusion irresistible. But now consider the equivoque: because an action takes place without our being conscious of it, the action is said to have had no sensation determining it. This, which is a truism when we limit Consciousness to one of the special modes Of Sensibility, or limit sensation to this limited Consciousness, is a falsism when we accept Consciousness as the total of all combined sensibilities, or Sensation as the reaction of the sensory mechanism. That a reflex action is determined by the sensory mechanism, no one disputes;468 whether the reaction of a sensory mechanism shall be called a sensation or not, is a question of terms. I have shown why it must be so called if anything like coherence is to be preserved in physiological investigations; and I have more than once suggested that the fact of intellectual processes taking place at times with no more consciousness than reflex actions, is itself sufficient to show that a process does not lapse from the mental to the mechanical sphere simply by passing unconsciously.
Inasmuch as an organism is a complex of organs, its total function must be a complex of particular functions, each of which may analytically be treated apart. Vitality is the total of all its physiological functions, and Consciousness the total of all its psychological functions. But inasmuch as it is only in its relation to the whole that each part has functional significance, and cannot therefore be isolated in reality, as it is in theory—cannot live by itself, act by itself, independently of the organism of which it is an organ, there is strict accuracy in saying that no particular sensation can exist without involving Consciousness; for this is only saying that no sensory organ can react without at the same time involving a reaction of the general sensorium. But since this general sensorium is simultaneously affected by various excitations each of which is a force, every sensation, perception, emotion, or volition is a resultant of the composition of these forces; and as there can be only one resultant at a time, to be replaced by another in swift succession, this one represents the state of Consciousness, and this state may or may not be felt under the peculiar mode named “Consciousness,” in its special meaning. In other words, the reaction of a sensory organ is always sentient, but not always consentient.
2. Let us illustrate this by the sensation of musical tone. When we hear a tone we are affected not only by469 the fundamental tone, representing the vibrations of the sounding body as a whole, but also by the harmonics or overtones, representing the vibrations of the several parts of that whole. It is these latter vibrations which give the tone its timbre, or peculiar quality; and as the harmonics are variable with the variable structure of the vibrating parts, two bodies which have the same fundamental tone may have markedly different qualities. There are some tones which are almost entirely free from harmonics; that is to say, their harmonics are too faint for our ear to appreciate them, though we know that the vibrations must be present. Apply this to the excitations of the sensorium. Each excitation will have its fundamental feeling, and more or less accompanying thrills of other feelings: it is these thrills which are the harmonics, giving to each excitation its specific quality; but they may be so faint that no specific quality is discriminated. A fly settles on your hand while you are writing, the faint thrill which accompanies this excitation of your sensory nerve gives the specific sensation of tickling, and this causes you to move your hand with a jerk. If your attention is preoccupied, you are said to be unconscious of the sensation, and the jerk of your hand is called a reflex action; but if your attention is not preoccupied, or if the thrill is vivid, you are said to be conscious of the sensation, and the action is no longer reflex, but volitional. Obviously here the difference depends not on the sentient excitation by an impression on the nerve, but on the state of the general sensorium and its consequent reaction. Had not the impression been carried to the sensorium, no movement would have followed the fly’s alighting on your hand, because no sensation (sensory reaction) would have been excited; the hypothesis of a purely mechanical reflex is quite inadmissible.
3. Or take another case. It sometimes happens that470 we fall asleep while some one is reading to us aloud. The sounds of the reader’s voice at first awaken the familiar thrills which give the tones their quality, and the words their significance; but gradually as sleep steals over us, the organism ceases to react thus; the words lose more and more of their significance, the tones lose more and more of their harmonics; at last we pass into the state of unconsciousness—we cease to hear what is read. But do we cease to feel? We have not heard, but we have been affected by the sounds. Not by distinguishable sensations; nevertheless a state of the general Sensibility has been induced. To prove that we have been affected is easy. Let the reader suddenly cease, and if our sleep be not too profound, we at once awake. Now, unless the sound of his voice had affected us, it is clear that the cessation of that could not have affected us. Or let us suppose our sleep to be unbroken by the cessation of the sound; even this will not prove that we have been unaffected by the sounds, it will merely prove that those sounds, or their cessation, did not excite a conscious state. For let the reader, in no louder tone, ask, “Are you asleep?” and we start up, with round eyes, declaring, “Not at all.” Nay, should even this question fail to awaken us, the speaker need only utter some phrase likely to excite a thrill—such as, “There’s the postman!” or, “I smell fire!” and we start up.
I remember once trying the experiment on a wearied waiter, who had fallen asleep in one of the unoccupied boxes of a tavern. His arm rested on the table, and his head rested on his arm: he snored the snore of the weary, in spite of the noisy laughter and talk of the guests. I called out “Johnson,” in a loud tone. It never moved him. I then called “Wilson,” but he snored on. No sooner did I call “waiter,” than he raised his head with a sleepy “yessir.” Now, to suppose, in this case, that he471 had no sensation when the words “Johnson” and “Wilson” reached his ears, but had a sensation when the word “waiter” reached his ears, is to suppose that two similar causes will not produce a similar effect. The dissyllable “Johnson” would excite as potent a reaction of his sensory organ as the dissyllable “waiter”; but the thrills—the reflex feelings—were different, because the word “Johnson” was not associated in his mind with any definite actions, whereas the word “waiter” was so associated as to become an automatic impulse.231
4. Two sisters are asleep in the same bed, and a child cries in the next room. The sounds of these cries will give a similar stimulus to the auditory nerve of each sister, and excite a similar sensory reaction in each. Nevertheless, the one sister sleeps on undisturbed, and is said not to hear the cry. The other springs out of bed, and attends to the child, because she being accustomed to attend on the child and soothe it when crying, the primary sensation has excited secondary sensations, thrills which lead to accustomed actions. Could we look into the mind of the sleeping sister, we should doubtless find that the sensation excited by the child’s cry had merged itself in the general stream, and perhaps modified her dreams. Let her become a mother, or take on the tender duties of a mother, and her vigilance will equal that of her sister; because the cry will then excite a definite reflex feeling, and a definite course of action. But this very sister, who is so sensitive to the cry of a child, will be undisturbed by a much louder noise; a dog may bark, or a heavy wagon thunder along the street, without causing her to turn in bed.232
472 Although during sleep the nervous centres have by no means their full activity, they are always capable of responding to a stimulus, and sensation will always be produced. When the servant taps at your bedroom door in the morning, you are said not to hear the tap, if asleep; you do not perceive it; but the sound reaches and rouses you nevertheless, since when the second tap comes, although no louder, you distinctly recognize it. In etherized patients, sensation is constantly observed returning before any consciousness of what is going on returns. “I was called,” says Mr. Potter, “to give chloroform to a lady for the extraction of ten teeth. The first five were extracted without the slightest movement, but as the operation proceeded, sensation returned, and I was obliged to use considerable force to keep her in the chair during the extraction of the last tooth. She came to herself very shortly after, and was delighted to find she had got over all her troubles without having felt it the least in the world.”233
5. We do not see the stars at noonday, yet they shine. We do not see the sunbeams playing among the leaves on a cloudy day, yet it is by these beams that the leaves and all other objects are visible. There is a general illumination from the sun and stars, but of this we are seldom aware, because our attention falls upon the illumined objects, brighter or darker than this general tone. There is a sort of analogy to this in the general Consciousness, which is composed of the sum of sensations excited by the incessant simultaneous action of internal and external stimuli. This forms, as it were, the daylight of our existence. We do not habitually attend to it, because attention falls on those particular sensations of pleasure or of pain, of greater or of less intensity, which usurp a prominence among the objects of the sensitive panorama. But just473 as we need the daylight to see the brilliant and the sombre forms of things, we need this living Consciousness to feel the pleasures and the pains of life. It is therefore as erroneous to imagine that we have no other sensations than those which we distinctly recognize—as to imagine that we see no other light than what is reflected from the shops and equipages, the colors and splendors which arrest the eye.
The amount of light received from the stars may be small, but it is present. The greater glory of the sunlight may render this starlight inappreciable, but it does not render it inoperative. In like manner the amount of sensation received from some of the centres may be inappreciable in the presence of more massive influences from other centres; but though inappreciable it cannot be inoperative—it must form an integer in the sum.
6. The reader’s daily experience will assure him that over and above all the particular sensations capable of being separately recognized, there is a general stream of Sensation which constitutes his feeling of existence—the Consciousness of himself as a sensitive being. The ebullient energy which one day exalts life, and the mournful depression which the next day renders life a burden almost intolerable, are feelings not referable to any of the particular sensations, but arise from the massive yet obscure sensibilities of the viscera, which form so important a part of the general stream of Sensation. Some of these may emerge into distinct recognition. We may feel the heart beat, the intestines move, the glands secrete; anything unusual in their action will force itself on our attention.
“What we have been long used to,” says Whytt, “we become scarcely sensible of; while things which are new, though much more trifling, and of weaker impression, affect us remarkably. Thus he who is wont to spend his474 time in the country is surprisingly affected, upon first coming into a populous city, with the noise and bustle which prevail there: of this, however, he becomes daily less sensible, till at length he regards it no more than they who have been used to it all their lifetime. The same seems to be the case also with what passes within our bodies. Few persons in health feel the beating of their heart, though it strikes against their ribs with considerable force every second; whereas the motion of a fly upon one’s face or hands occasions a very sensible and uneasy titillation. The pulsation of the great aorta itself is wholly unobserved by us; yet the unusual beating of a small artery in any of the fingers becomes very remarkable.”
7. A large amount of sensation is derived from the muscular sense, yet we are not aware of the nice adjustments of the muscles, regulated by this sensibility, when we sit or walk. No sooner are we placed in an exceptional position, as in walking on a narrow ledge, than we become distinctly aware of the effort required to preserve equilibrium. It is not the novelty of the position which has increased our sensibility; that has only caused us to attend to our sensations. In like manner, the various streams of sensation which make up our general sense of existence, separately escape notice until one of them becomes obstructed, or increases in impetuosity. When we are seated at a window, and look out at the trees and sky, we are so occupied with the aspects and the voices of external Nature, that no attention whatever is given to the fact of our own existence; yet all this while there has been a massive and diffusive feeling arising from the organic processes; and of this we become distinctly aware if we close our eyes, shut off all sounds, and abstract the sensations of touch and temperature—it is then perceived as a vast and powerful stream of sensation, belonging to none of the special Senses, but to the System as a whole.475 It is on this general stream that depend those well-known but indescribable states named “feeling well” and “feeling ill”—the bien être and malaise of every day. Of two men looking from the same window, on the same landscape, one will be moved to unutterable sadness, yearning for the peace of death; the other will feel his soul suffused with serenity and content: the one has a gloomy background, into which the sensations excited by the landscape are merged; the other has a happy background, on which the sensations play like ripples on a sunny lake. The tone of each man’s feeling is determined by the state of his general consciousness. Except in matters of pure demonstration, we are all determined towards certain conclusions as much by this general consciousness as by logic. Our philosophy, when not borrowed, is little more than the expression of our personality.
8. Having thus explained the relation of particular sensations to the general state of Consciousness considered as the function of the whole organism, we may henceforward speak of particular sentient states, as we speak of particular organs and functions, all the while presupposing that the organs and functions necessarily involve the organism, since apart from the organism they have no such significance. The reaction of a sensory organ is therefore always a sentient phenomenon. Apart from the living organism there can be no such vital reaction, but only a physical reaction. It is commonly supposed that sensation is simply the molecular excitation of the cerebrum; yet no one will maintain that if the cerebrum of a corpse be excited, by a galvanic current sent through the optic nerve, for instance, this excitation will be a sensation. Whence we may conclude that it is not the physical reaction or stimulus which constitutes sensation, but the physiological reaction of the living organism.
476 9. Now this is the point which the advocates of the Reflex Theory, implicitly or explicitly, always deny. Let us trace the origin of the fallacy, if possible. When we remove the eye from a recently killed animal, and let a beam of light fall on it, the pupil contracts. This is a purely mechanical action; no one would suggest that a sensation determined it. When we remove the leg, and irritate its nerve, the leg is jerked out. This is also a purely mechanical action. When we remove the brain from an animal, and pinch its toes, the leg is withdrawn or the pincers are pushed aside. Is this equally a purely mechanical action? And if not, why not?
The Reflex Theory would have us believe that all three cases were mechanical, at least in so far as they were all destitute of sentient co-operation, the ground for this conclusion being the hypothesis that the brain is the exclusive seat of sensation. The Reflex Theory further concludes that since these, and analogous actions, are performed when the brain is removed, they, being thus independent of sentience, may be performed when the brain is present without any co-operation of sentience. The grounds for this conclusion being the facts that in the normal state of the organism there are many actions of which we are sometimes conscious, and at other times unconscious; and some actions—such as the dilatation and contraction of the pupil—of which we are never conscious. This observation of parts detached from the organism seems confirmed by observation of actions passing in our own organisms, both converging to the conclusion that the actions in question are purely mechanical, involving no sentience whatever. We are taught, therefore, that there is besides the sentient mechanism, to which all conscious actions are referred, a reflex mechanism, to which all unconscious actions are referred. The cerebro-spinal axis, acting as a whole, constitutes the first;477 the spinal axis, acting without the co-operation of the cerebrum, constitutes the second.
10. Before proceeding with our exposition of the theory it may be well to state two considerations which must be constantly in view. If it should appear that there is any reasonable evidence for refusing to limit Sensibility to the cerebrum—and this evidence I shall adduce—the Reflex Theory must obviously be remodelled. Nor is this all. We might see overwhelming evidence in favor of the hypothesis that the cerebrum is the exclusive seat of Sensibility, and still reject as a fallacy the conclusion that because certain actions can be performed in the absence of the cerebrum, therefore those actions in the normal organism are likewise performed without cerebral co-operation. I mean that it is a fallacy to conclude from the contractions of the pupil, and the jerking of the leg, when eye and leg are detached from the organism, that therefore when eye and leg form integral parts of the organism, such contractions and jerkings are mechanical reflexes without sentient conditions. And the fallacy is analogous to that which would conclude from the observations of a mechanical automaton, that similar appearances in a vital organism were equally automatic and mechanical. So long as both sets of phenomena are apprehended simply as they appear to the sense of sight, they may be indistinguishable; but no sooner do we apprehend them through other modes, and examine the modes of production of the phenomena, than we come upon cardinal differences. A limb detached from the organism is like a phrase detached from a sentence: it has lost its vital significance, its functional value, in losing its connection with the other parts. The whole sentence is necessary for the slightest meaning of its constituent words, and each word is a language-element only when ideally or verbally connected with the other words478 required to form a sentence; without subject, predicate, and copula, no sentence can be formed. So the organic connexus of parts with a living whole is necessary for the simplest function of each organ; and a limb, or any other part, is a physiological element only when (ideally or really) an integral of a vital whole. The organism may be truncated by the removal of certain parts, as the sentence may be abbreviated by the removal of certain phrases; but so long as subject, predicate, and copula remain, there is a meaning in the sentence; and so long as the organic connexus needful for vitality remains, there will be vital function. The eye detached from the organism is no longer a part of the living whole, it no longer lives, its phenomena cease to be vital, its movements cease to have sentient conditions. The movements of the pupil may seem to be the same as those of the living eye; but when we come to examine their modes of production, we learn that t............