Popular Science Monthly/Volume 70/May 1907/Is the Mind in the Body?

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A NUMBER of years ago the eminent anatomist, Dr. Joseph Leidy, told me that a modern Maecenas had offered to pay for the finest microscopes if he would undertake a search in brains for ideas.

The professor, who never pretended to be either a psychologist or a philosopher, rejected the proposal on the ground that the investigation must be a profitless one. His common sense and common experience of mind and body led him to believe that mental phenomena are not things to be captured as the result of such a method of attack.

But what induced him to take this stand? Common sense and common experience, in some sense of the terms, men have always had—at any rate, they have had what may be called by these names from a very early period. And yet there was a time, and a very long time, during which such an investigation would not have impressed men of acuteness and learning as necessarily an absurd one.

There was a time during which, that is to say, men regarded minds as something frankly and unequivocally material. Something elusive, if you please; something too fine and subtle to be directly apparent to the senses; but, nevertheless, something just as material as wood or stone or flesh or bone, and just as really in this or that portion of space.

Almost at the dawn of reflective thought we find men identifying the mind with the breath which we inhale and exhale; and when, later, the time was ripe for the birth of an atomic theory, a crude and hasty one, it is true, but the forerunner of the one which was to appear later, we find them describing it as composed of atoms, which enter and leave the body as do other kinds of matter.

About four hundred years before Christ, Democritus, who was a man of scientific temper, even if of unavoidably limited scientific attainment, placed before the world his atomistic doctrine. A hundred years later that easy-going philosopher, Epicurus, adopted his theory, and founded a long-lived school. In the first century, B. C., the Roman poet, Lucretius, wrote his magnificent poem 'On Nature' and set forth in noble verse the Epicurean doctrine touching the universe of things physical and mental.

The nature of the mind and soul, says Lucretius, is bodily; for when it is seen to push the limbs, rouse the body from sleep, and alter the countenance and guide and turn about the whole man, and when we see that none of these effects can take place without touch nor touch without body, must we not admit that the mind and soul are of a bodily nature?

But of what sort of bodies must we conceive this part of a man to be composed? The mind acts with great nimbleness; it is very easily moved, so it is inferred that it consists of bodies very small, smooth and round:

The following fact, too, demonstrates how fine the texture is of which its nature is composed, and how small the room is in which it can be contained, could it only be collected into one mass: soon as the untroubled sleep of death has gotten hold of a man and the nature of the mind and soul has withdrawn, you can perceive then no diminution of the entire body either in appearance or weight; death makes all good save the vital sense and heat. Therefore the whole soul must consist of very small seeds and be inwoven through veins and flesh and sinews; inasmuch as, after it has all withdrawn from the whole body, the exterior contour of the limbs preserves itself entire and not a tittle of the weight is lost.[1]

Lucretius thinks that something analogous takes place 'when the flavor of a wine is gone, or when the delicious aroma of a perfume has been dispersed into the air.' Something is gone, but the weight of objects is not altered by the loss.

For hundreds of years it did not seem to men ridiculous to talk about the mind in this way. Yet they all had the common experiences of mental phenomena that we have. Nor was it the weakness of a single school to be thus grossly materialistic. The Stoic school, the great rival of the Epicurean, and also a long-lived one, was in its way as materialistic. The Stoics identified the soul of man with the warm breath that is found in his body.

Indeed, it is not too much to say that, among that very acute people, the Greeks, from whom we have gained so much, it did not seem at all unnatural to conceive of the mind of man as a breath, or a fire, or collection of fine small material particles. Some raised their voices in protest, but the protest was scarcely effectual.

Now, suppose someone had come to Lucretius and had initiated him into the mysteries of the microscope. Would he have scouted the idea of getting a direct vision of the 'seeds' that constituted the mind of man? I think not; there was certainly nothing in his doctrine to make the idea absurd to him. If, in general, invisible material things can be made visible, and the barrier set by their minuteness can be done away, why should not coughed-out soul atoms be captured and inspected?

But Professor Leidy was amused at the notion of the investigation proposed to him. Why was this? His experience of the mind was no more direct or complete than that of Lucretius. He had never given half as much thought to the nature of minds, for he was little interested in psychology. Nevertheless, his common sense—whatever that may be—led him to laugh at a way of looking at things that could not have struck Lucretius and many other able men as absurd at all.

It is extremely interesting to ask why the men of our day, I do not mean the professional psychologists, but the great mass of intelligent persons who do not care much for psychology, and who know little of philosophy, should take up certain ways of regarding things mental, and should unhesitatingly repudiate others which have once been popular. We can not in the least explain it by saying that their own experience of minds leads them to embrace such conclusions. As a rule, they do not reflect upon their experiences of their minds at all, and some of them are hardly capable of serious reflection upon the subject. As early as the seventeenth century, John Locke remarked that "the understanding, like the eye, whilst it makes us see and perceive all other things, takes no notice of itself; and it requires art and pains to set it at a distance, and make it its own object." To this modern psychologists will heartily subscribe.

The fact is that the average man's notions about the mind are a part of his share in the heritage of the race. He who knows something of the history of human thought finds in them the echoes of old philosophies—traces of theories sometimes the most fantastic. The common sense which guides men is the resultant attitude due to many influences, some of them dating very far back indeed.

I have said that, even among the ancient Greeks, there were protests against the materialization of the mind. Both Plato and Aristotle stood out against it, each in his own way. It is true that Plato distributes the soul through the body in a way that might strike an Epicurean as not unnatural—a part of it was below the diaphragm, a part of it in the chest, and a part of it in the head. But he does speak of this last and noblest part in somewhat the same tone as that in which men came later to speak of the human mind. Aristotle follows his teacher in regarding the reason, at least, as something to be carefully distinguished from everything material. However, it is interesting to note that he conceives of the divine reason, or first cause of motion, as touching the world without being touched by it.

May we not describe this last notion as material at one end, so to speak? If reason is so immaterial that it can not be touched by matter, what does it mean to say that it touches matter? But we must get used to queer ways of talking about minds, if we will follow the history of human thought. The seed dropped by Plato and Aristotle has grown into a tree when we come to Plotinus the Neo-Platonist, who lived in the third century after Christ.

Plotinus was-a man of mystical tendencies, but he was both learned and acute. He insists that the soul is an immaterial substance, and he tries to give us a notion of the way in which such a thing can be related to the body. To put it into the body, as Epicurus or Lucretius did, would be to deny its immateriality. This he can not do. To deny that it is related to the body at all is too much even for a philosopher.

In his perplexity he follows a middle course. He tells us that the soul is not in space and is not in things, in the strict sense. But in a certain sense it is in things, or is present to things. It is as a whole in the whole body, and is at the same time wholly in every part of the body; and is, thus, at once divisible and indivisible.

One may legitimately object to this curious doctrine, and criticize Plotinus as giving with one hand what he takes away with the other. It is easy to see what he tried to do, and what he actually did do. He tried to draw a clear distinction between mental phenomena and physical, and to tell us how they are related. He succeeded only in making of the soul an inconsistently material thing, existing in space in an inconceivable way.

But it will not do to treat Plotinus with contempt, and to pass over his doctrine as insignificant. He made an earnest attempt to draw a line between the mental and the physical—surely some such line ought to be drawn—and his influence upon men's minds has been enormous. His doctrine was taken up by Augustine, from whom it passed to the philosophers of the middle ages; and it came ultimately, after undergoing various modifications, to the modern philosophers. Distinct traces of it are to be found in some of the psychologies written at the present day and used in our colleges.

In the seventeenth century that remarkable man Descartes arrived at a fairly clear comprehension of the mechanism of the human body, and of the significance in it of the brain and the nerves. He concluded that the soul or mind has its 'chief seat' in the pineal gland in the brain, and that messages are carried to it from the various parts of the body. Yet he never ventured to put the soul quite frankly and unequivocally in the pineal gland. He still held that the soul was united to all the parts of the body 'conjointly'—the old Plotinic notion.

In other words, he did not go back to Lucretius, and he did not go forward to a clear distinction between mind and body. He remained halting in indecision; he left a dark place for his successors to illuminate with such light as they could furnish. They have been at the work ever since, and have had varying degrees of success.

Now the speculations of the philosophers, especially when they touch upon those things which are supposed to be of great moment to mankind, do not remain the property of the philosophers. They ooze out into general literature and become, so to speak, the common property of mankind. In the present instance, we find in the attitude of the majority of the cultivated persons who surround us to-day unmistakable traces both of the crude materialism which seems so natural to man when he first begins to think about the mind, and of the line of speculation indicated above. Men think of the mind as somehow in the body, in the brain; and yet they are not willing to admit that it is unequivocally in the body—in it as brain cells are, as blood corpuscles are, as are any of the material constituents of the body itself.

Ask the average undergraduate student—who can not be accused of having done much thinking for himself, but who holds the vague opinions that he has absorbed from those about him—ask him where his mind is, and he will probably answer that it is in his brain. Ask him, further, whether there is any hope of getting at it as one may hope to get at the material constituents of the brain, and I think he will say, No! It is there, and yet not exactly there; it is there in a Pickwickian sense. He feels as Dr. Leidy did, and his feeling has exactly the same foundation. It rests upon an ancient tradition.

What, then, is the relation of mind and brain? We seem to be left with an 'in' on our hands that is not really an in at all, but is something else. What is it? Our student can not tell us, nor can those from whom he has picked up his vague and inconsistent notions.

To those who wish to think clearly all this is naturally unsatisfactory. Those who busy themselves with the problem "are impelled to try to make the matter less vague. Now and then, even in our time, men go back, to accomplish this end, to something very like the ancient materialism which the world outgrew so long ago.

Thus we now and then hear it maintained that thought is a secretion of the brain. Half a century ago much was said about this, and to many the doctrine seemed plausible. It certainly does appear to make clearer the relation of mind and body, if we hold that mental phenomena are related to the brain as the saliva is related to the salivary gland. If we can say this, we may maintain that the mind is in the body in a literal and unambiguous sense of the word.

But may we legitimately speak thus? The secretion of a gland is a something so unequivocally material that it can be treated just like other material things. It can be collected into a test-tube and analyzed by the chemist. Has any one ever succeeded in filling a test-tube with mental phenomena? in bottling and analyzing in a laboratory pains and pleasures, memories and anticipations? Dr. Leidy, who knew a vast amount about the secretions of glands, did not confound ideas with secretions, and would not even attempt to treat them in the same way.

It is, indeed, too late in the world's history to try to revive the crude materialism of the past. Whatever else the philosophers have done, they have fixed our attention upon the striking distinction between mental phenomena and physical. He who has once grasped this may be a semi-materialist—an unconscious materialist—as is the plain man to-day, notwithstanding his assertion that the mind is immaterial; and as is his more learned neighbor the 'interactionist' psychologist, of whom I spoke in a recent paper in this journal.[2] But he can scarcely be a materialist out-and-out.

Hence, men have felt impelled to turn to other ways of making clear the relation of mind and body. Some have said that consciousness is a function of the brain; some, that it is the inside of that which, regarded from the outside, is brain-change; some, that it is the reality to which physical phenomena may be referred as appearance.

It is not well to let any one of these statements pass without scrutiny. What do we mean when we say that the mind is a function of the brain? Do we mean only that, given certain changes in the brain, certain mental phenomena come into being? It still remains to ask how the mental phenomena are related to the brain. Are they in there? and if not, where are they? or are they anywhere, in any intelligible sense of the word? The word 'function' is not a word to conjure with. We may call motion a function of brain molecules, if we choose; but evidently a memory or a feeling of pain is not a function of this kind, and the question still confronts us: What kind of a function is it?

As to the statement that mental phenomena may be regarded as the inside of that which, looked at from the outside, is brain-change—this we may take as merely 'a manner of speech,' as a something to say to troublesome persons who ask us difficult questions and must be answered at all hazards. When we say that seeds are inside of an orange, we know what we mean. They are things that occupy space, and can be found in the spaces that they occupy. A leather purse may be lined with silk, and it may contain silver; but try to line a leather purse with painful emotions, and to fill it with hopes and expectations! We play with the words 'inside' and 'outside' when we talk in this way, and it is not proper to play when one is philosophizing, some learned men to the contrary notwithstanding.

Nor should the words 'appearance' and 'reality' be abused recklessly. They have a proper meaning, and we ought to keep to it. We say that a tree seen at a distance looks small, but really is large; and we say that a stick stuck into water looks crooked, but really is straight. Certain experiences we look upon as appearances, and certain others, which for some reason we regard as more satisfactory or more normal, we speak of as realities. Both appearance and reality are given in sensation, and we observe a connection between them. They belong to the same order of experiences.

Thus, I may sit in the highest gallery of the opera house, and may say: What looks like a row of small shiny discs in the parquet is really a row of bald heads. Be it remarked that the reality in this case is a something that can unequivocally be located; it is in the parquet, and it occupies space. It can be seen close at hand, and it can be touched with the fingers. May I say that what seems to be a, brainchange in one of these heads really is a sensation of sound? Is the sensation of sound there? does it occupy space? is it literally in the head?

Evidently we are here again concerned only with 'a, manner of speech'—with a loose expression which cloaks one's ignorance, and which borrows what force it has from a false analogy. If we say that the sensation of sound is the 'reality' and the brain-change the 'appearance,' we abuse two respectable words, in common use, that nave a right to better treatment.

The truth is that it is better to recognize that mental phenomena must not be conceived after the analogy of material things at all. We may, of course, go on talking about mind and body as other people do. In common life a pedantic exactitude of expression is out of place. But when we try to be scientific we must strip off crude inherited materialisms, the echoes of a remote past.

The man who has done this the most completely is the parallelist. The limits of this paper prevent me from setting forth his doctrine, but I have elsewhere[3] tried to show simply and clearly just how much he has a right to mean by it. He denies frankly that the mind is in the body, as also that one has the right to hint, by the use of vague and ambiguous material analogies, that it is somehow in the body. It was a philosopher of the seventeenth century who first thought out the doctrine, but it was a scientist of the nineteenth century, Professor W. K. Clifford, who made it popular to us moderns. To him much of the credit for the present revival of the doctrine must be accorded.

  1. 'De Rerum Natura,' III., trans. Munro.
  2. Popular Science Monthly, February, 1907.
  3. 'An Introduction to Philosophy,' N. Y., 1906, chapter IX.