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

is operative, although it may not be discriminated from simultaneous feelings. When this is the case, we say the feeling is unconscious; but this no more means that it is a purely physical process taking place outside the sphere of Sentience, than the immoral conduct of a man would be said to be mechanical, and not the conduct of a moral agent. There is undoubtedly a marked distinction expressed in the terms Consciousness and Unconsciousness, but it is not that of contrasts such as Mental and Physical, it is that of grades such as Light and Darkness. Just as Darkness is a positive optical sensation very different from mere privation—just as it replaces the sensation of Light, blends with it, struggles with it, and in all respects differs from the absence of all optical sensibility in the skin; so Unconsciousness struggles with, blends with, and replaces Consciousness in the organism, and is a positive state of the sentient organism, not to be confounded with a mere negation of Sentience; above all, not to be relegated to merely mechanical processes.

52 a. Remember that, strictly speaking, Consciousness is a psychological not a physiological term, and is only used in Physiology on the assumption that it is the subjective equivalent of an objective process. To avoid the equivoque of “unconscious sensation,” we may substitute the term “unconscious neural process”; and as all neural processes imply Sensibility, which in the subjective aspect is Sentience, we say that Sentience has various modes and degrees—such as Perception, Ideation, Emotion, Volition, which may be conscious, sub-conscious, or unconscious. When Leibnitz referred to the fact of “obscure ideas,” and modern writers expressed this fact as “unconscious cerebration,” the first phrase did not imply a process that was other than mental, the second phrase did not imply a process that was other than physiological: both indicated a mode of the process known as Consciousness under other modes. There are different neural elements grouped in Ideation and Emotion; there are different neural elements grouped in Consciousness, Sub-consciousness, and Unconsciousness; but one tissue with one property is active in all.

53. The nervous organism is affected as a whole by every affection of its constituent parts. Every excitation, instead of terminating with itself—as is the case in most physical processes—or with the motor impulse it excites, is propagated throughout the continuous tissue, and thus sends a thrill throughout the organism. The wave of excitation in passing onwards beats against variously grouped elements—temporary and permanent centres—disturbing their balance more or less, and liberating the energy of some, increasing the tension of others, necessarily affecting all. Those groups which have their energy liberated set up processes that are either discriminated as sensations, or are blended with the general stream, according to their relative energy in the consensus. Thus the impulse on reaching the centres for the heart, lungs, legs, and tail excites the innervation of these organs; but as these are only parts of the organism, and as all the parts enter the consensus, and Consciousness is the varying resultant of this ever-varying consensus, the thrill which any particular stimulus excites will be unconscious, sub-conscious, or conscious, in proportion to the extent of the irradiated disturbance, which will depend on the statical conditions of the centres at the moment. A sound sends a thrill which excites emotion, causes the heart to beat faster, the muscles to quiver, the skin-glands to pour forth their secretion; yet this same sound heard by another man, or the same man under other conditions, physical or historical, merely sends a faint thrill, just vivid enough to detach itself as a sensation from the other simultaneous excitations; and the same sound may excite a thrill which is so faint and fugitive as to pass unconsciously. Physiological and psychological inductions assure us that these are only differences of degree. The same kind of physiological effect accompanies the conscious and unconscious state. Every sensory impression, no matter whether discriminated or not, affects the circulation and develops heat. The blood-vessels of the part impressed expand, vessels elsewhere contract—a change in the blood pressure has been effected, which of course implies that the whole organism has been affected. Delicate instruments show that at the time a sensation is produced the temperature of the brain is raised. The same is true of ideation. Mosso has invented a method of registering the effect of thought on the circulation. He finds ideation accompanied by a contraction of the peripheral vessels proportionate to the degree of intellectual effort. A young man translating Greek showed greater contraction than when he was translating Latin. During sound sleep—when we are said to be unconscious—sudden noises always cause contraction of the peripheral vessels. Psychological observation assures us that the conscious and unconscious states were both consentient, and were both operative in the same degree. The absorbed thinker threads his way through crowded streets, and is sub-conscious and unconscious of the various sights, sounds, touches, and muscular movements which make up so large a portion of his sentient excitation at the time; yet he deftly avoids obstacles, hears the sound of a hurried step behind him, recognizes an interesting object directly it presents itself, and can even recall in Memory many of the uninteresting objects which he passed in sub-conscious and unconscious indifference.

54. On all grounds, therefore, we must say that between conscious, sub-conscious, and unconscious states the difference is only of degree of complication in the neural processes, which by relative preponderance in the consensus determine a relative discrimination. We can only discriminate one thrill at a time; but the neural excitations simultaneously pressing towards a discharge are many; and the conditions which determine now this, and now the other excitation to predominate by its differential pressure, are far beyond any mechanical estimate. I mention this because the advocates of the Reflex Theory maintain that the neural processes are the same whether a sensation be produced or not; and that since the same actions follow the external stimulation whether sensation be produced or not, this proves the actions to be purely mechanical. I reply, the neural processes are not the same throughout in the two cases—otherwise the effects would be the same. You might as well say, “Since the explosion of the gun is the same, whether shotted or not, a blank cartridge will kill”; but if you tell me that your gun killed the bird, I declare that the cartridge was not a blank one. Whether the explosion of the gun also produced terror in one bystander, curiosity in a second, and attracted no notice from a third, will be altogether another matter. In like manner the sensory impression which determines a movement may or may not be accompanied or followed by other sentient states; the fact of such movement is evidence of its sentient antecedent; and an external stimulus that will produce this neural process, and this consequent movement, must produce a feeling, although not necessarily a discriminated sensation. Now since, for discrimination, other neural processes must co-operate, we cannot say that in the two cases all the neural processes have been the same throughout; nor because of this difference can we say that the process of the undiscriminated sensation is a mechanical, not a sentient process. In the next problem this point will be argued more fully.

55. The need of recognizing Consciousness and Consentience as degrees of energy and complexity in sentient states is apparent when we consider animal phenomena. Has a bee consciousness? Has a snail volition? or are they both insentient mechanisms? All inductions warrant the assertion that a bee has thrills propagated throughout its organism by the agency of its nerves; and that some of these thrills are of the kind called sensations—even discriminated sensations. Nevertheless we may reasonably doubt whether the bee has sentient states resembling otherwise than remotely the sensations, emotions, and thoughts which constitute human Consciousness, either in the general or the special sense of that term. The bee feels and reacts on feelings; but its feelings cannot closely resemble our own, because the conditions in the two cases are different. The bee may even be said to think (in so far as Thought means logical combination of feelings), for it appears to form Judgments in the sphere of the Logic of Feeling—το νοητικὸν; although incapable of the Logic of Signs—το διανοητικον. We should therefore say the bee has Consentience, but not Consciousness—unless we accept Consciousness in its general signification as the equivalent of Sentience. The organism of the bee differs from that of a man, as a mud hut from a marble palace. But since underlying these differences there are fundamental resemblances, the functions of the two will be fundamentally alike. Both have the function of Sentience; as mud hut and palace have both the office of sheltering.

56. The question of Volition will occupy us in the next chapter. Restricting ourselves here to that of Consciousness, and recalling the distinction of the two meanings of the term, we now approach the question of Unconsciousness. Are we to understand this term as designating a purely physical state in contrast to the purely mental state of Consciousness; or only as designating a difference of degree? This is like asking whether Light and Darkness are both optical feelings, or one an optical feeling and the other a physical process? On the Reflex Theory, no sooner does a vital and mental process pass from the daylight of Consciousness, or twilight of Sub-consciousness, into the darkness of Unconsciousness, than the whole order of phenomena is abruptly changed, they cease to be vital, mental, and lapse into physical, mechanical processes. The grounds of this conclusion are, first, the unpsychological assumption that the unconscious state is out of the sphere of Sentience; and secondly, the unphysiological assumption that the Brain is the only portion of the nervous system which has the property of Sensibility. Restate the conclusion in different terms and its fallacy emerges: “organic processes suddenly cease to be organic, and become purely physical by a slight change in their relative position in the consensus; the organic process which was a conscious sensation a moment ago, when its energy was not balanced by some other process, suddenly falls from its place in the group of organic phenomena—sentient phenomena—to sink into the group of inorganic phenomena now that its energy is balanced.” Consider the parallel case of Motion and Rest in the objective sphere. They are two functions of the co-operant forces, one dynamic, the other static; although markedly distinguishable as functions, we know that they are simply the co-operant forces now unbalanced and now balanced; what we call Rest is also a product of moving forces, each of which is operant, and will issue in a definite resultant when its counter-force is removed. Motion and Rest are correlatives, and both belong to the sphere of Kinetics. In like manner Consciousness and Unconsciousness are correlatives, both belonging to the sphere of Sentience.213 Every one of the unconscious processes is operant, changes the general state of the organism, and is capable of at once issuing in a discriminated sensation when the force which balances it is disturbed. I was unconscious of the scratch of my pen in writing the last sentence, but I am distinctly conscious of every scratch in writing this one. Then, as now, the scratching sound sent a faint thrill through my organism, but its relative intensity was too faint for discrimination; now that I have redistributed the co-operant forces, by what is called an act of Attention, I hear distinctly every sound the pen produces.

57. The inclusion of Sub-consciousness within the sentient sphere is obvious; the inclusion of Unconsciousness within that sphere may be made so, when we consider its modes of production, and compare it with the extra-sensible conception of molecules and atoms. The Matter which is sensible as