CHAPTER VI

HOW THE UNDERMIND WORKS

The Three Levels: Intelligence in the Lower Cen-
tres: Co-operation of the Overmind with the
Lowest Level: Co-operation of all
Three Levels.

We have seen that anatomy illustrates the psychological fact that the whole mind, both conscious and subconscious, is of one stuff, since it has the power of passing along the neurons, and is therefore nervous energy. Anatomy further enables us to say that mind, albeit of one stuff, does act on different levels, and that there are lower nervous centres (in the region of the undermind) which control the common functions of the body.

We may obtain a clearer notion of this by adopting Dr. Hughlings Jackson's division of the nervous system into three levels - the higher-level nervecentres, the middle, and the lower. Physiology reveals such a threefold division in the human brain itself, namely the cortex or upper brain, the midbrain or basal ganglia, and the lower brain or medulla. We may show this roughly in a diagram, thus

We must, however, not forget that this is a rough division, of which we can merely say that it does correspond with certain psychological and physiological facts. There is no hard and fast line between the three levels thoughts, feelings, and memories are constantly shifting backwards and forwards between the overmind and the undermind, for instance; and there is (as in blushing or in any voluntary action of the muscles) constant communication between the highest level and the lowest. Furthermore, each of these levels may be capable of further subdivision: in the highest level, for instance, voluntary action may be fine or base. We could not divide the noble workings of the human spirit into such concrete categories, since we should be dealing with a different plane: were we indeed able to give everything scientific classification we should probably have to put a divine level — a region, shall we say? of the Holy Ghost-containing every good gift, and every perfect gift" of religion, morality, science, and art, right above the top level of our diagram. None the less for practical purposes we can take the threefold division of the brain, and speak confidently of certain activities working mainly in certain centres, and together forming the mind.

Intelligence in the Lower Centres

The control of our bodily functions is mental, though it is subconscious. We have now to ask two questions: Is the work of this lowest level in the undermind merely mechanical, or does it show signs

of intelligent adaptation? And further, is the action of the lowest level correlated in actual experience with the middle level and with the conscious mind?

The functions of the body are controlled, we have said, by the lower centres; they belong to the bottom region of the undermind. It is nervous energy in the lower centres that produces the act of respiration, the beating of the heart, the regulation of the vasomotor system, the processes of secretion, excretion, and the rest.1 This action is mental because it is done by nerve-force, assisted by the independent action of living cells, of which we shall speak in the next chapter. But we do not by this mean that these processes are done by what we ordinarily call conscious intelligence; they are largely "automatic," that is to say, there is imprinted in each centre at or before birth a habit — or an instinct which is the result of the long exercise of generation after generation. We may express this in the words of a French writer, who says of respiration:

2

"Dans les lobes, dans les neurones des circonvolutions se trouvent en quelque sorte imprimés par suite d'une longue rétentivité et la notion du mécanisme respiratoire et le souvenir du besoin de l'hématose." 3

Down here, then, at the bottom of the undermind, there is enough "intelligence" and enough con

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1 For the sake of clearness I speak generally of lower centres, avoiding detail about the ganglia of the sympathetic and so forth.

2 Even when an organ is mechanically stimulated by the passing of a chemical substance from another organ, the source is still mental, for the chemical substance is itself secreted by nervous action in the originating organ.

3 Prof. A. Charrin, Les Défenses Naturelles de l'Organisme," 1898, p. 292.

sciousness" to do the work required just so much and no more; and to this subconscious mentality we ordinarily refuse the word consciousness, though indeed there is consciousness of a sort in every living organism. What sort of lower consciousness these centres possess may be imagined by considering the lower animals, whose life is entirely subconscious. Perhaps, for instance, the ganglia of the human heart have a slightly higher consciousness than a jellyfish, since they certainly have a higher nervous organism.

But the lower centres do not act altogether mechanically; they regulate their organs and act appropriately to their conditions. The digestive centres, for instance, have to discriminate between the heterogeneous food supplies that we give them to deal with; the vaso-motor system is constantly changing the supply of blood in different parts of the body with the most precise adjustment according to the varying circumstances of the moment.1 The circulation of the blood may sound at first mechanical enough (granted the initial wonder of the heart), and indeed most text-books describe it as the result merely of the action of a system of elastic tubes, connected with a self-acting force-pump; but "it is such views as these that degrade physiology and obscure the marvels of the body." "2 As a matter of fact the circulation never runs for two minutes in

1 For instance, in the regulation of the temperature, a balance must be struck between the gain of heat and the loss. "As in all such cases, the nervous system is arbitrator. By keeping a hand on both these processes, it maintains the temperature constant.' Rebmann and Seiler, The Human Frame, Eng. Trans., 2nd ed., 1901, p. 87.

2 Dr. A. T. Schofield, The Force of Mind, 1902, p. 54.

the same manner; the blood flows through the innumerable miles of capillaries which pervade nearly every tissue of the body, and these have to be opened or closed in different parts of the body with every change of temperature or position; at one moment they strengthen the brain for the work it is doing, at another they divert the necessary blood for muscular action or for the chemical processes of digestion.1 And of all these ingenious operations the conscious mind is unaware-if we had to direct them all, we should be doing nothing else day and night. But they are done with the required amount of care and discrimination in some region of the undermind.

No doubt many such acts are purely reflex, and there is a reflex element in them all; but there is also certainly an association in some. And in any case to say a thing is reflex does not remove it from the realm of intelligence, for the highest mental activities are also reflex: Keats' Ode to a Nightingale was a reflex action due to the song of that fowl — plus a rather considerable amount of asso

1 The effect of hypnotic suggestion upon the vaso-motor system shows how impossible is the old mechanical idea: e.g., the experiments of Professors Bernheim and Beaunis, and of Professor Forel who has by suggestion restored arrested secretions at a fixed hour (Revue de l'Hypnotisme, 1889, p. 298), of Dr. Burot who has lowered the temperature of a hand as much as 10°C. (Ibid, 1890, p. 278), of Drs. KrafftEbing, Bourru, Focachon, Ramadier, and others. Burot supposes that the mechanism employed is the constriction of the brachial artery, beneath the biceps: "How can it be," he asks, "that when one merely says to the subject, 'your hand will become cold,' the vaso-motor nervous system answers by constricting the artery to the degree necessary for achieving the result desired? That is a thing which passes our imagination."