§ 1. The Approach to the Problem. § 2. What Must Be Recognised from the Biological Side. § 3. What Must Be Recognised from the Humanist Side. § 4. Various Theories of the Relation of Mind and Body. § 5. Monistic Speculation along the Line of the Double-Aspect or Correlation Theory.
§ 1. The Approach to the Problem.
IT is with a heightened sense of responsibility that we turn to the ancient problem of the relation of body and mind. But it is a question in regard to which the biologist has something to say, and it cannot be evaded in a study of Animate Nature nor in prolegomena to a philosophy of Animate Nature. By the latter we mean a consistent thinking together of what we know and feel about Animate Nature along with what we know and feel about other orders of facts.
As the view to which a biologist is most naturally led may seem, at first sight, disappointing, and may even be misunderstood as a capitulation of the citadel of personality, we would plead that after we get past what seems to most thinkers the quite untenable position of crude materialism, with its Gothamite metaphysic, and what seems to most scientific workers the quite untenable position of subjective idealism, and the theory of epiphenomenalism, which is materialism in modern garb, the conclusion we come to does not imply any practical depreciation of the reality of the bodily system and activity on the one hand, or of spiritual values and the thought-life on the other. If we avoid the three fatal errors of false simplicity just mentioned, it is not perhaps of great moment what theorymonist or dualist, parallelist or animistwe are led to adopt. We must choose the interpretation which is most consistent with the rest of our thinking and experience.
What is familiar ground to the expert philosopher is full of pitfalls alike to the biologist and to the man in the street, and we probably do well to remind ourselves that the way we put the question of the relation between mind and body may be misleading. It is often asked: Is the body the real thing and the mind a derivative illusion? Or is the mind alone real and the body in some way dependent? These questions are badly put, for both bodily activity and the thought-life are real. A conviction of the actuality of the body as an agent to be reckoned with need not imply that the mind is in any way illusory. Nor need a conviction of the reality of the mind, readily reached by any one who has ever made up his mind, imply that the body is not substantial and effective. The practical truth is, that what we call the mind counts, and that what we call the body counts; or perhaps that what counts is body-mind or mind-body. So far there is general agreement. But are there two distinct and disparate real activitiesa player and an instrument, so to speak, or is there one order including both bodily and mental processes, metabolism and awareness of meaning? Is there interaction of two orders of being, or correlation within one order? (See Lloyd Morgan, 1915, p. 6.)
We know ourselves by our senses as organisms; we know ourselves also as thinking, feeling, purposing, endeavouring beings. For immediate experience there is unity. For scientific purposes, however, it seems almost necessary to separate off the two aspects, or processes, or systems, and the problem arises how we are to think of them in relation to one another. But the fact is that body and mind are alike abstractions. Prof. A. E. Taylor has said: The severance of the original unity of experience into a physical and a psychical aspect is entirely a product of our own abstraction-making intellect. Body and Soul are not given actualities of experience, but artificial mental constructions of our own (1903, p. 314).
Yet here again, while many of us are impressed in our experience with the inter-dependence rather than independence of these two aspectsbodily and mentalwe must admit that we do not find it an easy task to explain what we mean by the phrase two aspects in this particular connection. The words do not seem to grip.
In stating the problem Prof. Lloyd Morgan takes the case of the processes involved in seeing a candle. The rays of light affect the receptors of the retina, a physical relatedness (a), but as the stimulus passes by optic neurones to the visual centre in the occipital lobe of the cerebrum, there is a superadded physiological factor (b), so that the entire process may be called ab. But if we definitely take note of the candle and adjust ourselves deliberately to it there seems to be a third kind of relatedness, a psychical process, so that the whole process may be called abc. We have thus (1) the receptors in physical relation to the physical object; (2) the visual centre in physiological and physical relation to the receptors and through them to the object; and (3) something in psychical relation in some way to the visual centre, and through it to the receptors, and ultimately and essentially to the candle as representing the external world. This something we call the mind. (1915, p. 4) The mind is somehow a mid-term receiving messages from the object in the external world and issuing messages to the organs concerned in behaving appropriately to that object. Whenever the mind is thus effective in guidance we have what we called abc-process. The distinguishing feature in such guidance is a context of meaning within a sphere of interest. Using the term mind in this sense, we have to consider its relation to the processes that go on in the cortex of the brain, and, anticipating our subsequent discussion, we may say that there are two main views. According to the first there are two radically distinct and wholly disparate orders of beingthe mental order and the physical order, which interact. According to the second there is only one order within which there are distinguishable types of relatedness and of process, e.g., physical, physiological, and psychical. Any given term may be coincidentally related to other terms in these severally distinguishable ways. This is the abc-interpretation already suggested. On the second view the c process is always correlated with ab processes; on the first view the c process is independent of any physiological correlate.
§ 2. What Must Be Recognised from the Biological Side.
It is possible, as we have seen, to apply to a living body many of the methods of chemistry and physics, and to give chemical and physical descriptions of isolated observèd processes. The more that is done, the more will the distinctively vital stand out in relief. If it can be shown that the balsam's jerking out of its seeds admits of complete mechanical description in terms of tensions, elasticity, and the like the more obvious will be the distinctively vital factor in the sundew's fly-catching successes. But no adequate chemico-physical description has yet been given of any distinctively vital process. A new aspect of reality wells up within organisms, which are material systems none the less, and we require new concepts for its description. Even in their simplest forms organisms are integrated systems, capable of unified regulatory action and of registering experiences.
But just as the mechanical description has its limitations, so is it with the biological. In our study of Animal Behaviour we have seen evidence of the gradual disclosure of another aspect of reality which transcends the biological. Mentality wells up from the spring. It appears at first in traces only, so that we are not quite sure whether it is there or not, just as it is not very easy to be sure whether a calcareous Alga, or a dormant chrysalis, or a hibernating snail is living or not. But by and by there is a copious flow, and we have no hesitation in saying that the rook or the parrot, the dog or the elephant, has a mind of its own. The student of science is organically more interested in establishing the fact that the study of living things requires concepts which are not needed in the study of the heavenly bodies, than in a discussion of what, in principle, is meant by Life. Similarly he is more interested in establishing the fact that the study of animal behaviourand not in its higher reaches onlyrequires concepts which are not needed in the study of the everyday functions of the body, than in a discussion of what we mean by Mind. But we cannot be satisfied without at least facing the old problem of the relation between body and mind. It is in reality a metaphysical question, but the metaphysical interpretation must be consistent with what we know of the facts, and we shall begin by stating what must be recognised from the biological side.
Our theory of the relation of mind and body (if it be a relation) must be consistent with what we know of individual development. The intelligent mammal begins its individual life as a pinhead-like cell, and for a long time it must be admitted that psychological methods or formulæ are quite inapplicable. The developing ovum of a rabbit (fide Brachet) can go on developing for some time outside of the maternal body,it is a self-contained implicit organism. We do not understand how it is managed, but it has born with it the potentiality of the big brain and the intricate behaviour. There is a gradual emergence of reflexes, of tropisms, of spontaneous exertions, of experiments, of learning, of putting two and two together, of clever behaviour and, in man, of occasional wisdom. In our own case we are sure that as the minute structure of the cerebral cortex increases in complexity, the child becomes more intelligent; as the child becomes more intelligent, the cerebral cortex increases in complexity. Not a single nerve-cell is added after birth, but the inter-relations between the cells increase in number, and the brain becomes a labyrinth. There are no new nerve-cells, but there is normally no lack of new ideas in the growing boy.
(b) Our answer to the body and mind problem must be consistent with what we know of the historical facts. In the course of evolution the nervous system has become gradually more complex and behaviour gradually more masterly, wider in range, more fertile in resource. We do not wish to make too much of the nervous system, for the method of trial and error, for instance, is practised by animals with no nervous system at all, and a very definite capacity for learning may be exhibited by an animal, like a starfish, without a single ganglion in its body. But when we have made this admission we must advance to the other fact that evolution of brains and evolution of behaviour have proceeded hand in hand, in intimate correlation.
(c) The theory we frame as to the mind and body relation must be consistent with the fact of their functional inter-dependence. We express one side of this inter-dependence when we say, the spirit is willing, but the flesh is weak, which suggests the picture of a worn-out instrument unequal to the player's demands. We express another side of the inter-dependence when we say of our friend that he died in his prime, of a broken heart, having lost interest in life, which suggests the picture of a strong organisation or society crumbling away because of the resignation of one who was its heart and soul.
A large and a complex brain among Vertebrates is correlated with a dominance of intelligent behaviour. The more convolutions the greater the fulness and freedom of life. An intricate brain among Arthropods is correlated with subtlety of instinctive behaviour. Thus an important part of the ant's brain is big in the worker, smaller in the queen, and almost absent in the drone. Retardation or warping of the development of the nervous system is associated with enfeeblement or disharmony of mental life. Fatigue, or poisoning, or degeneration of the nervous system has its mental correlate. Injury to particular areas of the brain may bring about specific changes in behaviour, e.g., disorders of speech. It seems, for instance, that an area at the base of the third convolution on the left side of the brain is the seat of the impressions and processes associated with remembrance of the movements of articulation; that an area affecting the first and second left temporal convolutions is similarly associated with memory of the sound of words; that an area at the posterior part of the second parietal convolution on the left side is similarly associated with visual images of words and letters (see Bergson's Creative Evolution).
The senescence of the worker hive-bees after their all too strenuous short life is correlated with observable fatigue-changes in their brains, and the influence on the human nervous system of degeneracy of the thyroid gland is correlated with the semi-idiocy of cretinism. There is no question-begging in giving these illustrations of the way in which our mind's activity and development are bound up with the health and development of the body, for it is quite open to any one to hold that the brain, for instance, is the instrument in and through which the mind realises its desires and ideals. It may be held also, an expert psychologist writes, that the gradual failure of powers with old age or the temporary failure with illness or fatiguefailure which, though primarily physical, seems to reach to the very core of the mind's beingis defect not of the player, but of the instrument on which he plays, and through which alone his genius can find fitting expression (J. L. McIntyre; Hastings' Cyclopdia, vol. x, p. 778). Our present point is simply that, whatever be our theoretical interpretation, it must do justice to the facts of correlation. For whatever theory we adopt, these facts remain.
§ 3. What Must Be Recognised from the Humanist Side.
In pondering over the body and mind problem we must never lose sight of the supreme reality of mind. We need not dwell on the fact that we do not know anything of Nature save in the selective mirror of our minds; it is more important to insist on the positive reality of the thought-life, the most real fact in the world. There must surely be some bungling with words when the distinguished physiologist Prof. Jacques Loeb speaks of our existence being based on the play of blind forces and only a matter of chance, and of ourselves as only chemical mechanisms. Ideas are not impalpable will-o'-the-wisps, they have hands and feet. My mind to me a Kingdom is, not a dispensable emanation suspended tremulously over the physical, like the heat-haze over the cornfields. The starry firmament on high is scarce more awe-inspiring than the spiritual edificescientific and ethical, artistic and religiouswhich man has built outside himself. Neither in peace nor in war can we ignore the larger values of the true, the beautiful, and the good without imperilling body as well as soul. Whatever theory we adopt about body and mindmonist or dualist, correlationist or interactionist, organicist or animistthese facts remain.
One of Darwin's services was to show man's solidarity with the rest of creation, his affiliation to a mammalian stock. That this was a very important contribution to human thought is recognised almost unanimously, and no one any longer dreams that the dignity or value of a result is affected by the historical conditions of its becoming or evolution. Yet it seems fair to point out the risk, that focussing attention on the rock whence Man was hewn and the pit whence he was digged, may lead to an under-estimate of the apartness and uniqueness of Man as compared with the rest of creation. He is separated off by reason or the power of conceptual inference, by morality or the habit of controlling his conduct in reference to ideals, by the possession of true language or Logos. Man was the greatest of mutationsa new synthesis; and it is certain that in him organismal individuality finds a new and finer expression which we call Personality.
§ 4. Various Theories of the Relation of Mind and Body.
To the question how we are to think of our thought-life and our brain-life in relation to one another at least seven answers have been given, but we need not give all of them the same amount of attention. Two of them fall if we conclude, as we have done, that mechanistic formulation does not give an adequate account of the world of organisms. These two are (I) thoroughgoing materialism, and its modern representative, (II) epiphenomenalism. (I) According to thoroughgoing materialism, mind is fictitious and the only realities are matter and motion. Sensation, according to Hobbes, is nothing but motion; and the brain, according to Cabanis, secretes thought as the liver secretes bile. To this it may suffice to answer that the mechanical theory of organisms breaks down; that we cannot satisfactorily explain our thinking in terms of laws of matter and motion which are the results of our thinking; and that we cannot think clearly to ourselves the proposition that mind is a function of the brain, or that the motion of particles produces the emotion of joy.
(II) According to Huxley's epiphenomenalism, the stream of consciousness is like the chain of foam-bells on the river, called into existence by the real physico-chemical processes in the brain, and ceasing as these cease. The real causal sequence is to be found in the neuroses which are assumed to admit of mechanical formulation; the sequence of psychoses is due to that of the neuroses, for the elements of consciousness have no influence either on one another or on the activities of the creature. The psychoses are the shadows cast by the vanes of the cerebral windmill, or the creakings of the machinery, or at the best the electrical sparks which accompany the friction. There may seem to be two watches, but only one is going (the brain); when the going watch ticks there is an echoing tick in the other; nay more, by induction the going watch may cause movements of the hands of the watch which only seems to go. Perhaps the most generous image is, that the elements of consciousness are the short-lived foam-bells on the wonderful current of cerebral processes.
We cannot accept this view because it is wrapped up with the mechanistic hypothesis, because it hands over the reins of life to matter and motion, because it denudes the thought-life of all reality. When biologists become preoccupied with the psychical concomitants of blots in the brain, or with the localisation of particular mental functions in particular areas in the cerebral cortex, they are apt to lean towards epiphenomenalism, but this has to be corrected by trying to see life whole.
The epiphenomenalist theory (which regards mentality as a negligible phosphorescence of life) is to be rejected on common-sense grounds because we are sure that in human life consciousness and awareness of meaning count for much. It is rejected by most biologists because they cannot evade the conviction, we can hardly say conclusion, that mentality is pervasive throughout all creatures that exhibit genuine behaviour, associative memory, and profiting by experience; and because they find it difficult to believe in the elaboration and persistence of what is, on the epiphenomenalist theory, a useless by-play, counting for nought. And if it be asserted that the persistence and evolutionary elaboration may be accounted for because consciousness is the inevitable by-product of the all-important inter-relations of nerve-cells, then we have slipped back again into the slough of materialism. And it does not seem unfair to put to those who say that thinking is only the phosphorescence of an exuberant cerebral metabolism, the question, What, then, must the theory of epiphenomenalism be held to be? A will-o'-the-wisp looking at itself?
Against the theory that the mind does not count let us note the opinion of Professor Sherrington, one of the most distinguished investigators of the nervous system. In his important book The Integrative Action of the Nervous System, he says: The concomitance between certain nervous reactions and psychosis seems an alliance that strengthens the restless striving of the individual animal which is the passport of its species to continuance of existence (p. 333). Certain it is that if we study the process by which in ourselves this control over reflex action is acquired by an individual, psychical factors loom large, and more is known of them than of the purely physiological modus operandi involved in the attainment of the control (p. 390).
Only in the analytic laboratory or systematic museum can we rest satisfied with a view of Animate Nature which maintains that mind does not count. By sympathy if not by science we are sure that to leave mind out is a travesty of the facts. Especially in its higher reaches, life is suffused with feeling and meaning.
In his Birds and Man Mr. Hudson tells of what his brother once saw on a lonely sheep-farm on the southern frontier of Buenos Ayres. Immense numbers of upland geese in great flocks used to spend the cold months on the plains where he had his lonely hut; and one morning in August in the early spring of that southern country, some days after all the flocks had taken their departure to the south, he was out riding, and saw at a distance before him on the plain, a pair of geese. They were male and femalea white and a brown bird. Their movements attracted his attention and he rode to them. The female was walking steadily on in a southerly direction, while the male, greatly excited, and calling loudly from time to time, walked at a distance ahead, and constantly turned back to see and call to his mate, and at intervals of a few minutes he would rise up and fly, screaming, to a distance of some hundreds of yards; then finding that he had not been followed he would return and alight at a distance of forty or fifty yards in advance of the other bird, and begin walking on as before. The female had one wing broken, and, unable to fly, had set out on her long journey to the Magellanic Islands on her feet; and her mate, though called to by that mysterious imperative voice in his breast, yet would not forsake her; but flying a little distance to show her the way, and returning again and again, and calling to her with his wildest and most piercing cries, urged her still to spread her wings and fly with him to their distant home.
And on that sad, anxious way they would journey on to the inevitable end, when a pair or family of carrion eagles would spy them from a great distancethe two travellers left far behind by their fellows, one flying, the other walking; and the first would be left to continue the journey alone (Birds and Man. 2nd Ed., 1915, p. 214). The realm of animal life is crowded with this sort of thing.
(III) Also to be rejected is subjective idealism, which is the extreme antithesis of epiphenomenalism, and finds nothing real but the routine of personal conscious experience. This amounts to a denial of the existence of the physical world and of the possibility of science; it is the non-pos-sumus of solipsism.
(IV) A fourth viewcommon as a working-hypothesis at leastgoes by the name of psycho-physical parallelism. It admits the reality of both mental and cerebral processes, but regards them as concomitants merely, without interaction, two parallel causal chains, each complete in itself. We may think of two watches tied together, keeping perfect time, but constructed on different principles and using different notations. This view was subjected to what seems to us destructive criticism in Professor Ward's first course of Gifford Lectures on Naturalism and Agnosticism; but it is still held by some psychologists of distinction, either simply as a convenient way of formulating the facts, or with a metaphysical theory behind itnamely, an idealistic view of material phenomena.
Besides psycho-physical parallelism there are in the field three possible theories. One is much favoured by philosophers(V) the theory of psychical monism. Another view, (VI) the soul-theory or animism, does not seem to be favoured by many philosophers or by many scientific investigators, but may be true for all that. The remaining theory, much favoured by biologists, is (VII) the two-aspect or identity hypothesis. It seems to us that each of these theories has its particular advantages and its particular difficulties, and that a decision must at present be left with the individual according to his personal experience. In our judgment the biological facts mostly favour the two-aspect theory, but we have no assurance that it is the most valid.
(V) Psychical Monism. According to the doctrine of psychical monism, conscious process is the only reality, and though what we call physical objects and physical processes are also real, they owe their reality to being conscious processes or activities in disguise. We can formulate physical processes as if they consisted of the movements of bodies, but our formulation is purely symbolic. There are no things that move, nor things that have potential energy, there are no individualities outside the conscious stream. Things vanish away; things in themselves are regarded as mental in their nature. Needless to say, students of science are rarely attracted to this view. But it is to be suspected that the provocation to antipathy is in part due to confusing metaphysical and scientific language.
(VI) Animism. Of all the theories of the psycho-physical relation the oldest and perhaps the most attractive is animism, the soul-theory. In its clearest form it maintains the actuality of the soul as an embodied psychical being, which realises itself in interaction with the bodily organism. The soul is, apart from the bodily organisation, the ground of the unity of consciousness; it makes sensation, meaning, endeavour, and guidance possible. Its relation with the body is reciprocal, for while it controls the body, the bodily processes supply to it the content of consciousness. Interacting with the body, it develops into the centre of personality. It may conceivably attain to an existence independent of the life of its partner.
On Bergson's view, the brain is the medium between consciousness and the external conditions of life; it is the organ of attention to life, keeping the mind in contact with reality. But thought, he maintains, is in great part independent of the brain, and there is infinitely more in a human consciousness than in the corresponding brain. If the mental life thus transcends the cerebral life, if the brain serves simply to translate a small part of what goes on in mind, then personality is not permanently tethered to protoplasm.
The animist need not occupy the extreme position that the body is but an instrument on which the mind plays. Wiser and truer is the view that through the body the mind is educated, disciplined, and enriched. As Aliotta puts it, The body is not something with which the mind can dispense, it is not the forbidding prison which the Platonists depicted in such gloomy colours, it is no torture-chamber in which mind is doomed to expiate some mysterious crime, but rather the fertile soil in which alone the plant of spirituality can develop and blossom.
Among the advantages of animism we recognise (1) its emphasis on the supremacy and efficiency of what we call mind or spirit; (2) that it nevertheless faces the fundamental and all-pervading fact of body; (3) that its idea of interaction or reciprocal influence, though perhaps inconceivable, is a good working hypothesis, fitting many familiar facts; and (4) that it is congruent with that attractive and optimistic view of the world which assures us of the conservation of values. A spirited and scholarly defence of Animism has been furnished by Dr. W. MacDougall in his book on Body and Mind.
Difficulties in the Way of Animism. All the statements that have been proposed of the body and mind puzzle have their particular difficulties, and they are not awanting in the case of animism.
(a) The whole trend of science is to emphasise the influence of the bodily life on the thought-life, and although we are told that this only means that the soul cannot realise itself except in co-operating with its partner the body, we are haunted by the knowledge that particular defects in the instrument are terribly perturbing to the player.
(b) The experiences of mathematicians and other thinkers at a high level lead us to attach considerable importance to unconscious cerebration, to actual achievements on the part of the personality when the partner whose task is with thinking appears to be in abeyance.
(c) The characteristic feature of the animalistic theory is the idea of interaction, and this raises several serious difficulties. For how can the mind act on metabolism or metabolism on the mind? How can there be interaction between two disparate series? As Professor Stout (Manual of Psychology, Chap. III.) puts it, When we come to the direct connection between a nervous process, and a correlated conscious process, we find a complete solution of continuity. The two processes have no common factor. Their connection lies entirely outside of our total knowledge of physical nature on the one hand, and of conscious process on the other. It has been answered that the force of this difficulty is in the assumption that the two series are absolutely disparate, an assumption which the undeniable correspondence between the two series disproves. To positive vitalists there is no particular difficulty, for the non-material psychoid or entelechy which directs brain-processes will be readily susceptible to the influence of the mind; but this is a purely verbal relief, since it leaves us in face of the difficulty of the psychoid's or entelechy's capacity of acting on metabolism. We have admitted the difficulty of explaining what is meant by the two-aspect theory or the double-faced unity, but we are not sure that the idea of interaction is any more intelligible. We suggest, however, to those who uphold the idea, that the difficulty will appear less if it be recognised that the vital activities of the organism, considered apart from its psychical activities, are not susceptible of satisfactory mechanical description. When we have abandoned a mechanistic view of the organism, we have made a step of importance towards understanding what Professor Ward calls the internal or inter-subjective relation that the subject bears to its organism.
It is often said that animism involves a breach with the principle of the conservation of energy. If mind really counts, it is argued, work is done which the antecedent energy-conditions do not fully account for. If the mind acts on the brain in a way that tells, then some energy disappears from the books, for the mind is outside the sphere of energy-transformations. But to suppose that the mind acts on the material system without expending energy is, the critics of animism continue, to forsake scientific procedure, for the law of the conservation of energy cannot be broken.
Now we are not concerned in the defence of animism, but this criticism is not one that commends itself to us. The doctrine of the conservation of energy includes two propositions. In the first place, it suggests that the total amount of energy in the universe is a constant, but this is rather a pious opinion than an established fact. The less we say regarding the universality of the conservation of energy the better, for we do not know. But in the second place it is a regulative principle, based on experimental evidence, which states that in any closed physical system at work the energy expended in one way must be gained in another. The organism and its environment are comparable to the change-office outside an exhibition; there are ceaseless transformations, but the amount of cash is not only the same in the evening as in the morning, it is the same all through the day. The question is whether, with this regulative principle in view, we can think of mind acting on body or of body acting on mind?
Various answers have been given, and we shall take the worst first.