Problems of Life and Mind. Second series, George Henry Lewes [e book reading free TXT] 📗

were asked to use our toes as we use our fingers—to grasp, paint, sew, or write with them, we should find it not less impossible to control the movements of the toes in these directions, than to contract the iris, or cause a burst of perspiration to break forth. Certain movements of the toes are possible to us; but unless the loss of our fingers has made it necessary that we should use our toes in complicated and slowly acquired movements, we can do no more with them than the young infant can do with his fingers. Yet men and women have written, sewed, and painted with their toes. All that is requisite is that certain links should be established between sensations and movements; by continual practice these links are established; and what is impossible to the majority of men, becomes easy to the individual who has acquired this power. This same power can be acquired over what are called the organic actions; nevertheless the habitual needs of life do not tend towards such acquisition, and without some strong current setting in that direction, or some peculiarity of organization rendering it easy, it is never acquired. In ordinary circumstances the number of those who can write with their toes is extremely rare, the urgent necessity which would create such a power being rare; and rare also are the examples of those who have any control over the movement of the iris, or the action of a gland; but both rarities exist.

It would be difficult to choose a more striking example of reflex action than the contraction of the iris of the eye under the stimulus of light;214 and to ordinary men, having no link established which would guide them, it is utterly impossible to close the iris by any effort. It would be not less impossible to the hungry child to get on the chair and reach the food on the table, until that child had learned how to do so. Yet there are men who have learned how to contract the iris. The celebrated Fontana had this power; which is possessed also by a medical man now living at Kilmarnock—Dr. Paxton—a fact authenticated by no less a person than Dr. Allen Thomson.215 Dr. Paxton can contract or expand the iris at will, without changing the position of his eye, and without an effort of adaptation to distance.

To move the ears is impossible to most men. Yet some do it with ease, and all could learn to do it. Some men have learned to “ruminate” their food; others to vomit with ease; and some are said to have the power of perspiring at will.216 Now, if once we recognize a link of sensation and motion, we recognize a possible source of control; and if the daily needs of life were such that to fulfil some purpose the action of the heart required control, we should learn to control it. Some men have, without such needs, learned how to control it. The eminent physiologist, E. F. Weber of Leipzig, found that he could completely check the beating of his heart. By suspending his breath and violently contracting his chest, he could retard the pulsations; and after three or five beats, unaccompanied by any of the usual sounds, it was completely still. On one occasion he carried the experiment too far, and fell into a syncope. Cheyne, in the last century, recorded the case of a patient of his own who could at will suspend the beating of his pulse, and always fainted when he did so.

65. It thus appears that even the actions which most distinctly bear the character recognized as involuntary—uncontrollable—are only so because the ordinary processes of life furnish no necessity for their control. We do not learn to control them, though we could do so, to some extent; nor do we learn to control the motions of our ears, although we could do so. And while it appears that the involuntary actions can become voluntary, it is familiar to all that the voluntary actions tend, by constant repetition, to become involuntary. Thus involuntary actions, under certain limitations, may be controlled; on the other hand, the voluntary are incapable of being controlled under the urgency of direct stimulation. Both are reflexes.

Inasmuch as almost all actions are the products of stimulated nerve-centres, it is obvious that these actions are reflex—reflected from those centres. It matters not whether I wink because a sensation of dryness, or because an idea of danger, causes the eyelid to close: the act is equally reflex. The nerve-centre which supplies the eyelid with its nerve has been stimulated; the stimuli may be various, the act is uniform. At one time the stimulus is a sensation of dryness, at another an idea of danger, at another the idea of communicating by means of a wink with some one present; in each case the stimulus is reflected in a muscular contraction. Sensations excite other sensations; ideas excite other ideas; and one of these ideas may issue in an action of control. But the restraining power is limited, and cannot resist a certain degree of urgency in the original stimulus. I can, for a time, restrain the act of winking, in spite of the sensation of dryness; but the reflex which sets going this restraining action will only last a few seconds; after which, the urgency of the external stimulus is stronger than that of the reflex feeling—the sensation of dryness is more imperious than the idea of resistance—and the eyelid drops.

If a knife be brought near the arm of a man who has little confidence in the friendly intentions of him that holds it, he shrinks, and the shrinking is “involuntary,” i. e. in spite of his will. Let him have confidence, and he does not shrink, even when the knife touches his skin. The idea of danger is not excited in the second case, or if excited, is at once banished by another idea. Yet this very man, who can thus repress the involuntary shrinking when the knife approaches his arm, cannot repress the involuntary winking when the same friend approaches a finger to his eye. In vain he prepares himself to resist that reflex action; in vain he resolves to resist the impulse; no sooner does the finger approach, than down flashes the eyelid. Many men, and most women, would be equally unable to resist shrinking on the approach of a knife: the association of the idea of danger with the knife would bear down any previous resolution not to shrink. It is from this cause that timorous women tremble at the approach of firearms. An association is established in their minds which no idea is powerful enough to loosen. You may assure them the gun is not loaded; “that makes very little difference,” said a naïve old lady to a friend of mine. They tremble, as the child trembles when he sees you put on the mask. These illustrations show that the urgency of any one idea may, like the urgency of a sensation, bear down the resistance offered by some other idea; as the previous illustrations showed that an idea could restrain or control the action which a sensation or idea would otherwise have produced. According to the doctrines current, the Will is said to be operative when an idea determines an action; and yet all would agree that the winking which was involuntary when the idea of danger determined it, was voluntary when the idea of communicating with an accomplice in some mystification determined it.

66. There is no real and essential distinction between voluntary and involuntary actions. They all spring from Sensibility. They are all determined by feeling. It is convenient, for common purposes, to designate some actions as voluntary; but this is merely a convenience; no psychological nor physiological insight is gained by it; an analysis of the process discloses no element in a voluntary action which is not to be found in an involuntary action—except in the origin or degree of stimulation. In ordinary language it is convenient to mark a distinction between my raising my arm because I will to raise it for some definite purpose, and my raising it because a bee has stung me; it is convenient to say, “I will to write this letter,” and “this letter is written against my will—I have no will in the matter.” But Science is more exacting when it aims at being exact; and the philosopher, analyzing these complex actions, will find that in each case certain muscular groups have been set in action by different sensational or ideational stimuli. The action itself is that of a neuro-muscular mechanism, which mechanism works in the same way, whatever be the source of the original impulse. The stimulation may be incited directly from the periphery, or indirectly from a remote centre; and the action may be arrested by a peripheral or central stimulation: the reflex which ordinarily follows the excitation of a sensory nerve will be modified, or arrested, if some other nerve be at the same time stimulated. (See Law of Arrest, Prob. II. § 190.)

67. All actions are reflex, all are the operations of a mechanism, all are sentient, because the mechanism has Sensibility as its vital property. In thus preserving the integrity of the order of vital phenomena, and keeping them classified apart from physical and chemical phenomena, we by no means set aside the useful distinctions expressed in the terms voluntary and involuntary; any more than we set aside the distinction of vertebrate and invertebrate when both are classed under Animal, and separated from Plant, or Planet.

The mechanisms of the special Senses respond in special reactions; the mechanisms of special actions have also their several responses. The tail responds to stimulation with lateral movements, the chest with inspiration and expiration, and so on. These responses are called automatic, and have this in common with the actions of automata that they are uniform, and do not need the co-operation of Consciousness, though they do need the operation of Sensibility, and are thereby distinguished from the actions of automata. The facial muscles, and the limbs, also respond to stimulation in uniform ways, but owing to the varieties of stimulation the actions are more variable, and have more the character of volitional movements. With this greater freedom of possible action comes the eminently mental character of choice. In the cerebral rehearsal of an act not yet performed—its mental prevision—as when we intend to do something, yet for the moment arrest the act, so that there is only a nascent excitation of the motor process, there is a peculiar state of Consciousness expressive of this state of the mechanism: we call the prevision a motive—and it becomes a motor when the intention is realized, the nascent excitation becomes an unchecked impulse. The abstract of all motives we call Will. A motive is a volition in the sphere of the Intellect. In the sphere of Emotion it is a motor. Hence we never speak of the Will of a mollusc, or the motives of an insect, only of their sensations and motors. Yet it is obvious that the reflex in operation when a snail shrinks at the approach of an object is essentially similar to the reflex in operation when the baby shrinks, and this again is still more similar to that in operation when the boy shrinks: the boy has the idea of danger, which neither baby nor snail can have; the idea is a motive, which can be controlled by another idea; the baby and the snail can have no such motive, no such control—are they therefore automata?

68. If I see that a donkey has wandered into my garden, the motive which determines me to take a