Philosophy of the Unconscious

by Eduard Von Hartmann

  If we now ask how, of all the Central organs subserving the regulation of the bodily movements with respect to their situation in space, it is precisely the auditory ganglion that has come to be the most important, the key to this enigma must lie herein, that the specific sense of equilibrium is in the closest connection with the organ of hearing, and therefore has also been assigned for its central representation in the first degree to the same ganglion as the sense of hearing. This sense of equilibrium is located in the three semi-circular canals, which must be termed a manometer for the inner hydrostatic pressure variously exerted in the direction of the three axes situated at right angles to one another, and whose injury calls forth the same phenomena of giddiness and rotatory movements as those of the cerebellum itself. This organ of equilibrium ascertains the right position of the head in respect of the line of gravity, and as the attitude of the body in relation to the head is determined by sensations of touch, indirectly the position of the body as a whole. It is clear that this sense of equilibrium could only be developed pari passu with the evolution of the corresponding centre, and that this correlative development of the cerebellum must consist in the unfolding of reflex tendencies with a view to the regulation of the deportment according to the sensation of equilibrium. Thus the development of the centre for the sense of equilibrium soon outstripped that of the centre for the sense of hearing in the Hind-brain, and whilst the sense of hearing probably found pretty early a second central representation in the Fore-brain, the centre of equilibrium set itself with other subsidiary aids to fulfil its own task, in the first place, in alliance with the nervous bundles of the sense of touch of the whole body, in the second place, in conjunction with the sense of sight.

  From this connection there also results an explanation of the circumstance that among vertebrate animals living in water and air the development of the cerebellum is, on the whole, more considerable than in animals living on the surface of the earth. For in creeping and walking the sense of touch aided by the horizontal surface of the ground already affords a tolerable support, which makes the regulation according to the sense of equilibrium to appear less urgent, but in flying, and quite specially in swimming in deep water, the sense of equilibrium affords the chief, if not the sole, foundation of regulation.

  In man the original connection of cerebellum and sense of hearing is, strictly speaking, only displayed in two points—firstly, in that the nervous constitution of the organ of hearing is developed in the embryo from the vesicle of the Hind-brain; and, secondly, in that the musical rhythm received through the ear involuntarily impels to rhythmical movements. We shall not go far wrong if we designate the cerebellum the centre for dancing, and the fact that a weary troop marches on with fresh elasticity with the striking up of military music is explained by the fact that, instead of the fatigued cerebrum, corpora striata, and optic thalami, now the cerebellum as fresh organ especially undertakes the innervation of the muscles. Although almost all the senses seem to possess a tolerably perfect central representation in the cerebellum, yet on its destruction the sense-perception of the cerebral hemispheres is not affected. This is proved by the latter receiving no class of sense-perceptions (not even those of hearing) through the medium of the cerebellum in the sense in which they receive the visual perceptions through the medium of the corpora quadrigemina.

  The hemispheres of the cerebellum are, with the exception of the hemispheres of the cerebrum, the sole centre, which has developed a cortical layer of grey matter, and this circumstance points to the fact that the passage from the compact nuclear formation to that of a superficial distribution serves in both cases the same end. This end can only be the reflexion of the provinces of the body in provinces of the grey cortical layer. A compact nucleus is more adapted to the collection of impressions streaming in from the periphery into an indivisible whole. Where, however, the point in question is how to act on any single province of the whole body apart from the rest, a superficial distribution of the acting layer will be a more suitable formation for the distinct separation of the motor innervation of different provinces than a compact nucleus affording no facilities for the separation of the several parts. Although the attempt to prove the mirroring of the provinces of the body in the cortical layer of the cerebellum has not as yet succeeded, we shall still be obliged to assume it, relying on the analogy of the cortical layer of the cerebrum, where this proof has recently been forthcoming for the several parts.

  Whether the functions of the cerebellum are really exhausted with the performances of which we have spoken must be considered as at least doubtful. In any case, it is in the vertebrate animal kingdom the first centre to be developed, and even in man the most highly developed centre next to the Fore-brain, and it would certainly be rash to assert that our knowledge had at present exhausted the purpose of this organ.

  10. The Fore-Brain. —By the experiments of Fritsch and Hitzig definite centres of innervation have been proved to exist in the grey cortical layer of the cerebral hemispheres for particular groups of muscles (e.g., for the extensors of the fore-leg, the flexors of the fore-leg, the muscles of the neck, the muscles of the hind-leg, &c.), lying together in a limited part of the anterior and lateral surface (W., p. 16S). The places in question have already reacted on weak galvanic currents, and if the stimulation of other parts has not hitherto been followed by motor or sensory effects, that perhaps lies partly in an unsuitable intensity and quality of the stimuli applied, partly in the rapid blunting of the irritability in consequence of the exposure of the brain. Extirpation of the motor centre alluded to causes disturbance of the movements in question of some duration, but, in course of time, a normal state of things recurs.

  Another part of the anterior lobes has long been known by pathological observations as a centre of language. Speechlessness or aphasia is divided into an atactic and an amnesic kind; in the former the patient will not succeed in giving the conception which floats before his mind its linguistic sign; in the latter, different words are confused with one another. Perhaps this difference points to two different centres, which must co-operate in the function of language (W., p. 230).—Further supports for the exact determination of the distribution of the central seat of perception and innervation are still entirely wanting, and the assertions of phrenology rest on weak foundations.1

  In the large hemispheres more than in any other part of the brain the several groups of ganglia can act vicariously for one another, and therefore injuries and disturbances, which do not at the same time affect the corpora striata or the peduncle of the cerebrum, disappear more easily and completely than in any other centre whatsoever. Considerable losses of substance of both hemispheres, or onesided loss of a whole hemisphere, are sustained by pigeons without permanent change in their behaviour, and by rabbits and dogs with a certain loss of intelligence. Even in man total destruction of a cerebral lobe without palpable disturbance has often been observed, although here more widespread injuries of both sides are always sure to be accompanied by motor disturbances, more rarely by those of the senses or of the psychical functions (W., p. 222).

  These facts prove that, although specific tendencies to definite functions are found in the cortical layer of the cerebrum at certain places, these specific energies have here still only a relative, not an absolute, importance; that here, too, they are only a consequence of habituation to a certain kind of action continued for generations, whose nature again is conditioned by the commissural connections and the stimuli conveyed by the same (W., p. 231). If these connections and the relations to the rest of the nervous system depending thereon change, in spite of the (partly innate, partly individually acquired) dispositions in a short time other specific functions are exercised by the parts concerned, so that no break occurs in the psychical and organic functions as a whole.

  This substitution is favoured partly by the anatomically uniform nature of the grey cortical substance in all parts of the hemispheres, partly by the extraordinarily rich and numerous conn
ections of the several parts with one another. These connections, if we disregard the fibres of the Corona forming the continuation of the ascending path, are of three kinds: (1) the callosal fibres which form commissures between similarly situated parts of both hemispheres; (2) the arcuate fibres which unite the cortical surface of neighbouring sinuses; and (3) the longitudinal commisures which put remote parts of each single hemisphere into communication with one another (W., p. 157).

  It is only the abundance and excellence of these paths which makes possible such a facile psychical communication of all the ganglionic cells of the anterior brain with one another, that their more vivid perceptions flow together into a single consciousness by the act of communication and comparison, which, e.g., does not obtain between the perceptions of the cerebellum and those of the fore-brain. Now, as that consciousness which philosophises and writes books is the consciousness of the cerebral hemispheres, it is evident that it cannot know anything directly of a consciousness of the cerebellum; it is an ignoring of the impossibility of gazing directly into the consciousness of the cerebellum with the philosophising consciousness, when Wundt and others think they can from this fact deny a consciousness of the cerebellum and of the sensory centres (W., p. 713–715). Undoubtedly there exist paths of communication between all the other nerve-centres and the cerebral hemispheres, so that not merely all peripheral provinces of the body, but also all subordinate central organs obtain representation in them; but these connections must, for teleological considerations, be rendered difficult in order that the whole advantage of the division of labour among independent centres, and the disburdening from common work thereby effected, and the concentration on mental interests, may not be lost again for the fore-brain. Either, therefore, the existing paths will serve only for transmitting commands to the executive sub-officers, or (as on the part of the corpora quadrigemina) to conduct the synthetically prepared material of sensation, or only specially powerful and strong impressions are telegraphed to the fore-brain. In all cases, however, the large hemispheres are conscious of the stimuli conducted from other centres (just as those directly received from sense organs) only as their own stimulations, for what is perceived is only the modification of one’s own condition by the stimulus. Reciprocal action is wanting in the same sense in which it takes place among the ganglion-cells of the hemispheres, and from which the compound phenomenon of a consciousness of a higher stage of individuality results through the comparison of both perceptions in both cells. In lower animals, e.g., the Cyclostome fishes (Myxine and Petromyzon), where no one of the five parts of the brain has attained decided predominance, but all five regulate their affairs separately, such co-ordination as there is being due to simple superposition, although the parts are not without organic connection, there can be just as little talk about an indivisible consciousness as representative of the organic unity of the individual as in a tapeworm, a piece of coral, or an oak tree, although in these instances the relations between the different consciousnesses become ever looser. The Myxine has not one but five brain-consciousnesses, which only in their totality, along with the numerous consciousnesses of the spinal cord and other cells, represent the whole psychical life of the animal. Man is altogether in the same case; one of those five, however, the consciousness of his cerebral hemispheres, has been so uniquely developed in advance of all the others, and has acquired such a predominance over the latter, that it includes in itself not only qualitatively and quantitatively the chief part of the psychical life of the individual man, but also has become, by taking the lead in the government of the motor muscles, the psychical counterpart of the organic unity of the human individuality. Wundt altogether mistakes these relations when he lays down the false proposition that the consciousness of a coherent nervous system must always be a single one, and that therefore within a nervous system different co- or sub-ordinate kinds of consciousness may be assumed to be impossible (714 above, 715 below).

  It was mentioned above that the fore-brain is originally an olfactory ganglion; in the human embryo the development of the nervous foundation of the organ of smell still proceeds from the most anterior vesicle of the brain. Even in the cartilaginous fishes the olfactory organ is prominently developed, and the anterior part of the Fore-brain is prolonged into two “olfactory lobes” which in many higher vertebrata unite to form an “olfactory bulb.” In man, where not only the hemispheres have attained an extraordinary size as organs of ideational activity, but also the sense of smell falls into the background as compared with the other senses, the olfactory centre is also of moderate size, and is tolerably concealed in the basal part of the head of the corpora striata. The circumstance that fibres of the olfactory nerve as well as bundles of motor-fibres of the peduncle of the cerebrum meet here leads us to conclude, that from this spot those reflexes are effected which are initiated by odorous impressions (W., p. 202).

  The remaining mass of the corpora striata, together with the nucleus lenticularis, is to be regarded as an intermediary for the conduction of the impulses of the will from the lobes of the hemispheres to the muscles (W., p. 203). This is confirmed both by vivisection and in the case of man by pathological evidence, as also by the parallelism of the development of the hemispheres and corpora striata in the animal kingdom. The disturbances of movement of the nature of paralysis after apoplectic fits spring very frequently from apoplectic inhibitions of function in the corpora striata, and in man the result of disease of the corpora striata and of the motor parts of the hemispheres is pretty much alike, save that in the latter case recovery takes place much more easily. The corpora striata are accordingly (apart from the olfactory centre) to be designated centres for the co-ordination of voluntary movements (initiated by the hemispheres). They execute on a single voluntary impulse combined movements, whose mode of combination may be partly innate, partly acquired by practice, but which are still always felt as voluntary movements so far as the hemispheres are conscious of their impulse of innervation, and merely not conscious of the intermediary functions concerned in the execution of the mandate.

  11. The Co-operation and Subordination of the Nerve-centres .—Having in the preceding sections examined the functions of the different parts of the nervous system, we are in a position to render an account to ourselves of the purposive connection of the whole.

  Whoever should approach the organism of the higher vertebrata with the preconceived opinion that in it, as in the plant, everything is accomplished by democratic co-operation of cell-individuals with equal rights, would, when he considered the intensive concentration of the sway of the higher over the lower elements and of the cerebral hemispheres over the whole, be convinced that he was possessed by prejudice. Whoever, on the other hand, from the standpoint of a one-sided psychology should bring with him the opposite opinion that a single central organ guides and governs all, that nothing happens without its order, and everything happens only as it has been prescribed even to the smallest detail, would again have to be taught by the facts that, in spite of a rigid centralisation for the common interests of the collective organism, and in spite of a certain sovereignty of the supreme authority, this latter is yet relieved of all pettifogging details, because the principle of the self-government of subordinate spheres is thoroughly carried out in a remarkable manner. The whole organism is only developed and preserved by the continual self-activity of all the single individual cells, as the state only by the self-activity of all the citizens; but the social activity of these individuals is not, as in the simple form of a small democratic republic, uniformly distributed, but graduated in many ways.

  The individuals arrange themselves in groups or families of the most diverse form, each of which represents a higher stage of individuality, and endeavours to fulfil a higher individual aim; the groups likewise coalesce into circles, and these into provinces, and the provinces obtain a government of their own through special functionaries. As such a province we may understand the sum of those parts of the organism which are traver
sed and innervated by one and the same nerve. The magistracy of the provincial government of such a province would be the first centre in the spinal cord (or in the brain) with which the particular nerve comes in contact, i.e., into which it enters or from which it springs. These provincial governments now have further governing-bodies, which however are only distinguished partially by local demarcation from the sub-offices pertaining to them, in another part by qualitative separation of their departments like the various ministries within the same central government. Lastly, over these different provinces is enthroned the chief of the executive, who, however, has at the same time reserved to himself a province of his own for independent work. The various ministers here, however, form no council, but each rules independently over his own sphere; and although between related provinces direct communication takes place to facilitate common functions, yet the establishment of complete unanimity is not left to their collective agreement, but is assured by the direction which they collectively receive from the highest power in the state.